NPRs Research

very initial steps...

2007-10-05T16:36:00.000Z

State College, Wednesday.

The afternoon seminar was by Mocioiu (Penn State) who talked about me favourite sub-atomic particle, neutrinos. The discussion was mainly focussed on what we've learnt about neutrinos over the last 10 years, and it seems, quite lot such as - non-zero masses, flavour switching, physics beyond the SM of PP (and this is even before taking cosmological results into account!). Now, instead of trying to understand neutrinos from the Sun, we are beginning to get in a position to understand the Sun from neutrinos (inner fusion processes etc.) She also talked about atmospheric neutrinos from *VERY* high energy cosmic rays (>10^9 Gev), and current experiments aiming to detect them. However, the bottom line of this (for me) was that no-one has yet to see a single very high energy neutrino from a cosmic ray and the most distantly detected neutrinos are still from 1987A...

Thursday a.m.
Spent most of the morning trying to write a potential introduction to, ahem, my next paper. Basically trying to motivate a cross-clustering analysis of LRGs and QSOs...

Thursday p.m.
Got a little bit side-tracked in doing a lit review for current/past papers on the Alcock-Paczynski effect, only to discover Bohdan Paczynski actually died earlier this year :-(

Worked a little bit more on my PSU TLT and am realising that this needs to be finished before I can start working on my LBNL talk!!

Already struggling...

2007-10-03T19:26:00.000Z

Well, it seems as if getting back into daily postings is gonna be tricky...

Yesterday:
- V. good talk by Nemmen (UFRGS, Brasil) about models and modelling jets produced by supermassive black holes in nearby giant ellipticals (e.g. Allen et al. 2006). He basically made a good case that the spins of these black holes needs to be high (a=0.75 -1), with thick ADAFs, which to me, isn't *that* surprising. (Nemmen et al., 2007, MNRAS, 377, 1652)

- Continued to get up to `proper' speed with the SDSS and CAS/DAS.

- Went over some absolutely basic celestial sphere geometry/astronomy

Today.

- Sat in on an Astro 291 class in case I have to cover for Don on Friday. Was good to go over the basics of Planck distributions, leading to L = Area.sigma.T^4 and then to work out how many x-ray photons one can expect to emit in a human lifetime (clue: really not that many...)

Half an orbit

2007-10-02T03:04:00.000Z

Good evening and welcome back to NPRs Research.

After some time (6 months, ahem!) I thought it was a grand idea to get the ol' blog fired back up and see what we can do.

For those that don't know, I successfully handed in and defended my thesis at Durham University in May/June of this year, and have now been at Penn State University, working with Don Schneider for the past 2 and a bit months.

So, what's the grand plan? Well, if I'd knew I'd tell you, but basically, for starters and in four words, Sloan Digital Sky Survey.

To that end, I re-read the Stoughton et al. (2002) Early Data Release (EDR) paper today, as well as got to grips with the main papers in Xiaohui Fan's recent collection, regarding the high-redshift (z>5.7) quasars in the SDSS and the epoch of reionization. Then just as I was potentially about to so something useful, the server died. Ah well, looks like we're back to normal already...

Is Pluto a planet?

2007-04-03T12:18:00.000Z

All (known) bodies in the Solar System larger than 200 miles in diameter.

AATAC 07B

2007-03-07T12:30:00.000Z

The first version of me AAOmega LRG clustering paper has been posted to the AAOmega LRG BAO collaboration and have already had some really good comments back from key members.
This is all geared towards the AATAC 07B deadline next week (March 15th) and will be very interesting to see once more what happens.

As a slight spin-off from the w(theta) work that myself and Sawangwit (Durham) have been doing, I've been corresponding with Martin White (Berkeley) and Michael Brown (Princeton) regarding their Bootes NOAO Deep Wide-Field Survey (NDWFS, e.g. White et al. 2007 and Brown et al. 2007 ). The preliminary result is that the HOD models they employ from the clustering results to infer merger rates of >L*red galaxies, could match my 2SLAQ LRG xi(r) real-space correlation function very nicely (with the obvious health warning about comparing data/models with compeltely different selections). What this means we'll still need to have a think about!

LRGs vs. ELGs

2007-02-23T14:59:00.000Z

Hot off the press... (and therefore still very prelim)

With the help of Angulo et al. (2007) I think we *finally* have a delta_w estimation for (what would have been/still could be) an LRG ATLAS BAO Survey versus a WiggleZ Emission Line Galaxy (ELG) Survey.
Basically, given the parameters which should appear in due course in Ross et al. (2007a), (as well as looking at Parkinson et al. (2007) and the method of Angulo 07), I/we think the LRG delta _w would be 8.4% vs. an ELG value of 11.5% (essentially for equal telescope time).

However, this is all fairly academic since only one project at the mo has got the green-light ...

Why I'm proud to be Scottish...

2007-02-23T14:57:00.000Z

The only link to NPRs Research this has, is both are primarily connected to statistics and alcohol. Ahem.

All good things...

2007-02-19T14:59:00.000Z

After 7 plus years, my time in Durham is drawing to a close, especially as pasteurs new beckon...

However, to this end, there will be many send offs. This starts tonight with "The End of an Era" as Dr. Scales, Dr. Butterley and myself have a couple of beers with old friends.

The week of "celebration" looks set to continue on Friday with a potential school outing to Wet n Wild.
The boys in Room 311 are so looking forward to this event, they've even set up a wiki. Superb!

Meanwhile, the AAOmega Pilot/Clustering paper is now looking v. nice with good comments from Cannon (AAO), Wake (Durham) and of course El Shankso (Durham).

w(theta)'s

2007-02-12T11:46:00.000Z

Well, it's back to that old favourite of the Supervisor - w(theta)'s!! Now, normally, I wouldn't be too bothered about the whole thing, but I have to keep reminding myself that Tom was publishing papers on w(theta) (Shanks, 1980) in the month I was getting born!! so, the current issue is why does my AAOmega LRG w(theta) of the riz-selected galaxies have a lower amplitude than the equivalent 2SLAQ sample. Possible explanations include not quite getting ride of the unclustered stars in the projected function, or a more remote possibility, some real evolution, as can be seen by this recent paper.

late time ISW

2007-02-05T18:34:00.000Z

Excitement in the office late on this afternoon. Shanks (Durham) got very motivated about the connection between the ISW effect, SZ effect and (the lack of) lambda. Some choice Scottish words were muttered but the bottom line is Sawangwit and Bielby will (possibly) have a trio of really nice papers by then end of the month.

If nothing else, will make Enrique Gaztanaga's seminar on Wednesday definitely worth attending.

mulling things over...

2007-02-01T10:47:00.000Z

Dear Loyal readers,

All too often I have to apologise for lack of recent posts. This time is no exception.

The little bit of research news I do have is that with my recent work on Spitzer data, Alexander (Durham) and I have a very good chat about the connections between SMGs (a la Swinbank, Coppin and Geach - aka Athos, Porthos, and Aramis) and their connection to local ULIRGs - and consequently their BH fueling and growth rates. The link to quasars and BH growth phases is still v. much up for grabs and I would love to give you the punchline here but this is Dave's work and is due out shortly.

Also giving a shout out to a fellow quasi-collaborator, Angulo (2007) is shaping up v. nicely. Basically, this work takes the AMAZING Millenium Simulation, sprinkles in a little bit of the ol' semi-analytic model and basically tells you what error you're likely to get on a BAO survey, given certain things i.e. halo mass, (linear) object bias, the z-space distortions and so on. Again, watch this space!

Burns Night

2007-01-25T17:38:00.000Z

The best bits are at the start and end:

Some hae meat and canna eat,

And some would eat that want it;

But we hae meat, and we can eat,

And sae the Lord be thankit.

Then this:

Fair fa' your honest, sonsie face,               (sonsie = cheeky)
Great chieftain o' the puddin-race!
Aboon them a' ye tak your place,                 (aboon = above)
Painch, tripe, or thairm:
Weel are ye wordy o' a grace
As lang's my arm.

etc. etc. etc.

Of course, the Loyal Toast...

Hmmm. Then a toast to the "lassies" (whatever they are...)
and then maybe some dancing.

Crazy!!!

(PS In case you were wondering, yes, this post has very little to nothing to do with astronomy or thesis writing....)

Things I'm finding out when writing-up (1)

2007-01-23T17:43:00.000Z

A reason not to wholly go on citation counts.

This paper apparently only has 87 citations. WTF??

Desperate Housewives

2007-01-17T22:52:00.000Z

Just relaxing this evening, catching the end of Desperate Housewives (one of Dez's favs! ;-)

Anyway, another v. good day at the office, fuelled by the ever-efficient Prof TS and some good, early-doors feedback on the AAOmega clustering Letter/paper. Thanks to Sawangwit (Durham) for providing some v. nice Bruzual-Charlot models for my riz-plots. Have a couple of things to check first thing tomorrow morning but things looking kinda nice.

For the third, sorry, I think fourth attempt, am trying to get the easymosiac going on the Spitzer COSMOS 8micron data.

In other news, Bielby (Durham) now has >500 LBGs. Nice. Very nice. Room 301 is rivaling, maybe even leading, the other postgrad offices. Hee hee hee!!

not much news really

2007-01-16T17:52:00.000Z

Current page count: 112

Not mega-progress, but Ross et al. (2007a) is coming along v. nicely and in "prelim-final" draft stage with the supervisor...

TBs Viva on Thursday, 18th January, 9am.
DSs Viva is apparently on a Wednesday....

Good luck boys!!

When the night has come and the land is dark and the moon is only light we'll see...

2007-01-08T17:21:00.000Z

Happy and Healthy New Years Everyone!!

Hmmm, what will oh7 bring.....

Well, now that I'm (kinda) in full writing-up mode, the "research" nature of this blog will probably take a slight hit, but instead to replace that we're gonna have a "Thesis Progress Monitor" - courtesy of
Butterley and Saunter (Durham). Ha ha ha!!!!

Anyway, NPRs thesis is currently 108 pages in length (probably an errorbar of about 2 pages on that due to formatting etc.). The chapters are basically all in place and I'm beginning to get that nice "seeing how everything fits into the bigger picture" feeling.

Said thesis will probably not win any prizes but I'm really feel it will be worth a PhD qualification.

A Christmas Carol

2006-12-21T16:26:00.000Z

Well, everyone is off but Room 301 (Messers Ross, Bielbly and Sawangwit) are still hard at it with the Boss cracking the whip....

However, results are coming thick and fast. I'm continuing on thinking about the cosmic infrared background, ULIRGs at z~2 and the tie to star-formation/black hole fueling... Meanwhile, coming to a theatre near your in early 2007, Ross et al. 2007a continues to just get better and better.

Also, Bielby (Scarborough) is about to find huge SZ effects that'll bring down WMAP . Superb!

And then it's Vic at 6pm and Ricardos at 6:30pm. What a way to end the year!

So, NPRs Research is off on its hols for a couple of weeks but don't worry loyal readers, we will be returning in the New Year.....

Lots of love and cosmic kisses,
nic

Done (2).

2006-12-20T19:10:00.000Z

Dez has printed out and submitted.

I'm off tae join the boys for a celebratory curry and drink... ("the keg is the fridge" ;-)

The Bone was right about something....

2006-12-20T19:07:00.000Z

Writing postdoc apps really gets the creative juices flowing!!

Been investigating ULIRG clustering today. Fascinating stuff.
Fan et al (2004), Farrah et al. (2006, x2) and the on-going link-in with QSO (Croom et al. 2005) and obviously LRG (Zehavi et al, 2005; Ross et al. 2006) clustering.
Had some really good ideas too for future projects....

I also appreciate now why everyone has been going on about this "wee IR space satellite"!!

Done. (1)

2006-12-19T19:37:00.000Z

Tim has finished his thesis!!

Get in!!!

He came and told me this. And then also said he was bored.

(DJS so so nearly there...)

Good news/Bad News

2006-12-19T19:28:00.000Z

Good news. I now know (as much as one can in these sort of things) exactly what I need to get done to finish my thesis. Get in. I think it's gonna be a good 'un.

Bad news. For various reasons (e.g. continued job apps!!!!, football, Nozbo baiting*, ULIRG paper reading, going over weak lensing principles, door key logistics, double checking our Groop nite oot, wishing folk off for the Festive Period, blogging) I did nothing today towards this goal.
Ah well.

"72 hours of telescope time, that's an awful lot for a 4m project..."
"Why does Subaru produce four times as many papers as Gemini?"
"Globs, what are they good for exactly?"
and potentially the worst of all...
"Newcastle are crap"

Some names and numbers

2006-12-17T22:15:00.000Z

My curosity got the better of me and like a bad cat, I just
couldn't resist....

FIRST AUTHOR PAPERS
(NASA ADS statistics, 17th December 2006, 22:15 GMT)

Ross, NP: 1 paper (0 published); 0 cites; 0 normalised cites
Crain, RA: 1 (0); 0; 0
Norris, MA: 1 (1); 3; 1
Bett, P: 1 (0); 4; 1
Geach, JE: 3 (2); 6; 1
Radburn-Smith, DJ: 2 (2); 9; 3
Angulo, R: 1 (1); 18; 3
Harker, G: 1 (1); 29; 6
Libeskind, NI: 3 (3); 32; 5
Frith, WJ: 6 (6); 56; 23

Shanks, T: ~63; 858; 299
Ellis, RS: ~114; 1388; 656
Frenk, CF: ~40; 1643; 521
Smail, IR: ~55; 2249; 529
Cole, SM; ~29; 2614; 794

Peebles, PJE: 178+ papers/booksl; >11970 cites, >10,000 normalised

Notes: ~ implies not just papers but conference proceedings etc.

Anyone else I should include??

0612400

2006-12-14T20:25:00.000Z

I would say to the House, as I said to those who have joined this Government, 'I have nothing to offer but blood, toil, tears and sweat.'

IMBHs

2006-12-13T14:17:00.000Z

IMBHs - The evidence is growing!! (astro-ph paper today here)

Also, the COSMOS team has obviously been scared by my recent Spitzer work in their field and has a host of papers out today as well.

Job apps proceed in earnst!

Job apps

2006-12-12T15:52:00.000Z

I would think most people would agree that very few things on this tiny wee blue earth are more boring than jobs apps. However, I the world we live in, they are (obviously) vital.

Today/this week is (polishing) job apps week....

An un-refereed paper with nearly 1000 citations...

2006-12-08T16:53:00.000Z

This unrefereed paper has (as of 15:55 GMT, 12th December 2006) 933 citations.

Discuss!

100*

2006-12-08T14:55:00.000Z

Durham. Friday.

Crain (Durham) not only kept the high FLT standard up, he pushed the envelope and took it to the limit one more time. The motivation for the current work was wondering what processess, AGN feedback, "gastrophysics" etc., affect properties of dwarf galaxies - those galaxies where the current theoretical LFs still slightly disagree with observations. We were treated to a quick review of this paper and then presented with some new work and adjoining movies. A very recently completed gas dynamic movie showed the formation, re-ionisation and then merger of two dwarfs (galaxies). Sweet. The talk was both stimulating, information and present with the usual Crain panash. Watch out world, this boy's gonna take some stopping.....

Crikey!!

2006-12-07T11:49:00.000Z

Crikey!! There's been a lot of good stuff going on recently.

First off, the "Water on Mars" story. Obviously, I'm very sceptical bout some dodgey NASA publicity shots (where some grad student has no doubt photoshopped a slightly lighter grey smudge onto a greyscale image, for funding reasons...) but to be honest, Mars most very likely did have a simple compound such as H20 present at some point in its history. This does NOT mean that life is just around the corner though!!!!

Then there was the Wednesday seminar by Kennicutt (IOA) talking about - and showing some spectacular images - from the SINGS Survey. I'll try and get old of some of the sweet ass images in due course but this all tied in v. nicely as an overview and general motivation for the work I've been doing with Spitzer COSMOS data.

Spitzer-COSMOS field

2006-12-05T12:46:00.000Z

Well, COSMOS team, you may have had all the telescope team, reduced data, expertise, postdocs etc. etc. etc. but (with big thanks to Metcalfe, Norris and Bielby, all Durham ;-) I'm well on your heels. Once I get the Geachbo in on this, all that effort may have been for nothing.... hee hee hee

(finally) bearing fruits....

2006-12-05T12:42:00.000Z

(What I think is) another really nice 2SLAQ paper got posted to astro-ph Monday.

Check out Sadler et al. and quoting the last sentence of the abstract, "the evolution seen in the low-power radio-galaxy population implies that the total energy input into massive early-type galaxies from AGN heating increases with redshift, and was roughly 50% higher at z~0.55 (and up to a factor of two higher at z~1) than in the local universe."

i.e. AGN-galaxy feedback models beware!!

What's wrong with advertising??

2006-12-04T16:01:00.000Z

United Nuclear.

"Together we can observe/model the galaxy!"

2006-12-03T13:43:00.000Z

Once again this weeks FLTs (Friday Lunchtime Talks) continued the trend of high quality presentations of which there have been several lately and that I've got used to in the XGal Group at Durham.

Geach (Durham) gave a very sexy little number on "Exploring the z > 1 Universe with WFCAM near-IR narrowband surveys", essentially describing how with a sleak H2S1 narrow-band filter, his team is going after a nice big sample of z~2.2 galaxies in the COSMOS and Subaru Deep Fields via locating H-alpha. Very nice. There was claims also for potentially discovering z~9 galaxies (since this is where Ly-alpha would fall in their narrow-band) but with a K-band limiting magnitude of "only" 20.5, I wasn't sure how this was going to work unless lensing comes into play again (which of course this lot are world experts!).

Almeida's (Durham) talk I was really looking forward to as it was on "The properties of Luminous Red Galaxies in hierarchical galaxy formation model". Superb! Essentially Almeida has run simulations with GALFORM using two different models. There is the Baugh et al. (2005) model (with top-heavy IMFs among its many features) and the Bower et al. (2006) model (with AGN feedback incorporated). These two models predict a wide range of galaxy properties and they can be compared to those observed from the SDSS at z~0.24 (see eg the v. nice paper by Barber et al. ) and then at redshift z~0.5 (where good ol' 2SLAQ is in its prime).

For me, the bottom line is this. Both models do a pretty good job on most properties (e.g. Luminosity functions, stellar mass, ages) with the Baugh model probably being "truer" to real life. A couple of properties, metalicity and for me, the z~0.5 clustering don't quite seem to completely line up, but the reproduction tio the Masjedi et al. (2006) result is mega-impressive. This suggests that there is/can be more than one LRG per halo.

The theoretical sizes seems to give the biggest headache for these models as the sizes of the simlutaed galaxies are still (substantially) underestimated. All in all, when this gets polished off and finished, I think it's gonna be a VERY nice piece of work. BTW, this all still fits in with the "the most massive galaxies formed early on and have done v. little since" idea which I'm now (along with many others) convinced by.

On a more general note, the continued "Observers vs. Theory" rhetoric sometimes pisses me off - and each side is as bad as the other. Lucey (Durham) is one of the main protaginists for the "the theorists just fiddle their models to get the right answer" while comments such as those from Frenk (Durham) of "the simulations will tell you the right answer" is equally as annoying! Surely it's the synergy between observation and theory (and instrumentation) that make the group at Durham so powerful. Baugh, Almeida, Wake and myself have greatly benefitted from the discussions from both sides of the aisle.

Finally, on much more mundane methods, I re-submitted Ross et al. on Friday (yay!), though did not post to astro-ph as intended (boo!). The refs comments and suggestions have ended up being v. helpful and hoepfully have turned a good paper in to a great one (tee hee hee!! ;-)

Class A drugs

2006-12-01T12:11:00.000Z

A great philosopher once wrote
Naughty, naughty, very naughty
Ha ha ha ha ha

There's a guy in the place
He's got a bittersweet face
And he goes by the name of Ebeneezer Goode
His friends call him Eezer and he is the main geezer
And he'll vibe about the place like no other man could
He's refined, he's sublime, he makes you feel fine
Though very much maligned and misunderstood
But if you know Eezer he's a real crowd pleaser
He's ever so good, he's Ebeneezer Goode
You can see that he's mischievious, mysterious and devious
When he circulates amongst the people in the place
But once you know he's fun and something of a genius
He gives a grin that goes around from face to face to face
Backwards and then forwards, forwards and then backwards
Eezer is the geezer who loves to muscle in
That's about the time the crowd all shout the name of Eezer
As he's kotcheled in the corner, laughing by the bass bin

Eezer Goode, Eezer Goode
He's Ebeneezer Goode
Eezer Goode, Eezer Goode
He's Ebeneezer Goode
Eezer Goode, Eezer Goode
He's Ebeneezer Goode
Eezer Goode, Eezer Goode
He's Ebeneezer Goode
He's Ebeneezer Goode

Has anybody got any veras
Lovely
Ha ha ha ha ha
Ha ha ha ha ha

A great philosopher once wrote
Naughty, naughty, very naughty
Ha ha ha ha ha

Ebeneezer Goode, leading light of the scene
Know what I mean, see
He created the vibe
He takes you for a ride and as if by design
The party ignites like he's comin alive
He takes you to the top, shakes you all around
Then back down, you know as he gets mellow
Then as smooth as the groove that is making you move
He glides into your mind with a sunny Hello
A gentleman of leisure, he's there for your pleasure
But go easy on old Eezer he's the love you could lose
Extraordinary fellow, like Mr. Punchinello
He's the kind of geezer who must never be abused
When you're in town and Ebeneezer is around
You can sense a presence in the sound of the crowd
He gets them all at it, the party starts rocking
The people get excited it's time to shout loud

(Massive) Galaxy/Quasar evolution solved!

2006-11-29T12:21:00.000Z

Last paragraph in Section 4 of this paper.

Ah well. Looks like we all need to start looking for new jobs...

There are more things in heaven and earth, Horatio

2006-11-28T10:39:00.000Z

Wake (Durham) and I think we may have discovered something interesting about the 2SLAQ LRG Radio galaxy population. The clustering strength of the Radio matched 2SLAQ LRGs seems to be stronger than the "regular" LRG population. On closer inspection, this still is the case, even when we take into account the higher luminosity of the radio sample. If this result holds, this could be very interesting (and potentially a nice little paper...)

On a slight departure from this blogs regular theme - and a potentially more controverstial note - discussions with Watling (Durham) last night led me to question the validity of the Apollo missions.

However, for virtually every conspiracy theory on tinternet, there is another site de-bunking it and Bad Astronomy is as good as any for this one. It still cracks me up mind (as JPS pointed out) that on the Moon footage, as Neil Armstrong is trying to make an historical recording, you just see Buzz space-hopping about in the background, having the time of his life. And why not!

"SDSS-III"

2006-11-27T14:39:00.000Z

Sometimes things that really should seem pretty effing easy, really just take me ages to program up. This seems to be the case for the latest estimates of my AAOmega "field-to-field" errors. I also suspect that one of the fields (d05) is dominating the fit....

Hogg's Research (in some ways, the parental page to NPR's Research) mentioned "SDSS-III" recently. I first heard about this at (the now infamous) Frontiers conference. The plan is to use the Sloan telescope, LRGs (I think) and possibly photo-z's (??) to go after Dark Energy and indeed the equation of state parameter w (where P = w \rho) at z=~0.6 and z=~0.3. This is all very exciting, because a) it is exactly what we wanted to do with AAOmega b) this is all right up my street. Anyway, I have my own thoughts on all of this, which will no doubt eeek out over time....

Maybe I really do care about globs...

2006-11-26T15:13:00.000Z

Afternoon all.

First off, a couple of comments about "Globular Clusters Systems and Elliptical Galaxies", which was the title of one of the Friday lunchtime talks. Norris (Durham) convinced us that the colour-metallicity link in globs is not straight-forward (are these things ever) with the former essentially being bi-modal, the latter not. Thus when you study a sample of ~100s of globular clusters from around 8 or so nearby elliptical galaxies, you conclude the globs formed *very* early on, in situ with the galaxy itself. The glob-spiral link is still up for debate though. Very nice stuff. Maybe we all should care about globs after all...

Gao (Durham) gave the other FLT, which can basically be summed up by saying "we have no clue when, how or where the very first generation of starts formed".

On the paper front, after a horrible Wednesday but really good Thursday and Friday, the referees comments and subsequent corrections have been finished. The paper has gone back to the 2SLAQ collaboration for one (*final*) time and may well appear on astro-ph before the end of term. Yay!!

Those sneaky hobbitses

2006-11-21T10:57:00.000Z

We had our Friday Lunchtime talks today (it's Tuesday, something to do with dinosaur hunters, branes and Dome C....)

Crighton (Durham) talked about "The latest estimate of the primordial deuterium abundance" and essentially said a) D/H is reasonably hard to do b) we're probably underestimating the systematics when using QSO absorbtion sight-lines to do this sorta stuff c) in general, we're probably underestimating systematics when it comes ot (light) element abundances. Thus BBNS measurements (including 7Li, ahem) is probably in line with CMB Omega_b estimates, and the Universe is safe for another day.
Meanwhile, I'm left to wonder how much a varying fine-strucutre constant screws all this up.

Stott (Durham) got the juices flowing with a overview of his current research, "Evolution of Red Sequence galaxies in X-ray luminous clusters out to z=0.5". A comparison between the "local", z~0.1 LACRS (Las Campanas Cluster Redshift Survey) and MACS (Massive Cluster Survey) at z~0.5 is the primary driver.
JPS wowed us with pictures of galaxy lenses ("here, here and here") and poised the question, "we see little red things in today's clusters, but why don't we see them in clusters at redshifts of a half???". Some sweet stuff.

Let me get this right....

2006-11-14T22:02:00.000Z

NASA (with a little bit of help from the nice folk at ESA) are planning to put a 6 1/2 tonne contraption on top of a heavy life Arianne 5 rocket. Then, they'll light the blue touch paper and retire, so that said contraption with its nano-precision optics experiences upto 10G while blasting off, in an effort to get to this pseudo-mythical "Lagrangian 2" point in deep space. L2 is so far away that no shuttle can reach it, indeed, anything can happen before you even get there.

However, if you do reach this point roughly 1.5 million kms from the Earth, that's when the fun starts. The solar panels have to deploy. This I surmise then gives the contraption spacecraft enough power to open its sun-brolley (which incidentally is the size of about 4 tennis courts). After this various motors (or whatever) have to whizz, purr, whine such that a 6.5m beryllium primary mirror opens, perhaps to within micron-accuracy precision accuracy. All the while, the secondary snaps down into place like a flimsy picnic table, all for the bargain price of $10 billion probably by the time it all gets done.

And if you don’t believe any of this me, just look here.

(Oh, yeah, and did I mention this will find the first galaxies that ever formed over 12 billion years ago, directly observe planets actually in the very initial stages of being build around nearby stars, and general revolutionise astronomy, science and personkinds understanding of the majestic awe that is the Universe).

The two greatest redshift surveys ever, or a house of cards???

2006-11-13T17:57:00.000Z

Dear breaders (blog-readers),

As some, all or none of you might be aware, I received the referees report for my 2SLAQ LRG clustering paper last week. On the whole, the feedback was (very) positive and am sure the refs comments will make it stronger, better paper. Muchos appreciatas.

However, me being a Hibs daft footy fan and playing for Ustinov AFC, I always like a good "discussion" with the referee and this might seem to be no different. Essentially what is at stake is the entire legacy of the SDSS and 2dFGRS. I kid you not.

The question, my friends is, "In any given redshift survey, what determines the maximum scale at which your survey can probe?" (Answers on a postcard/email/blog comment post. Winner gets an honourable mention in the Ross et al. acknowledgments!! ;-)

I have my own ideas - thanks Cole (Durham) for help here - but if I'm/we're incorrect, not only are my results capoot, the whole house of cards will tumble too!!

I drove all night...

2006-11-12T13:49:00.000Z

Sunday. In the office, listening to Roy Orbison, which now automatically makes me think of JEG - eeek!!

Yup, it's squeaky bum time.

Setting a few things up to run overnight. Nothing too fancy. Re-doing me CV
(academic and non-academic) and actually making me feel pretty good about myself.

;-)

referees report

2006-11-09T10:51:00.000Z

After a couple of semi-hectic days earlier on this week, yesterday and today are spent answering
the referees report for me baby. Things looking pretty healthy and will be hoping to get the vast majority of this done by the weekend.

Meanwhile, having been discussing with Bielby (Durham) clever ways in which to do BAO measurements at redshift~3, where his v. nice sample of 400 LBGs are. This was all inspired by this paper.

back to errors

2006-10-31T18:29:00.000Z

Been a quiet couple of days recently. After the excitement of the discovery of the Ross-Shanks supercluster (which of course is well-know to the COSMOS team!) I've started my attempts on calculating errors on the AAOmega data. This should be relatively straight-forward, but I've heard that one before!

Also Sadler (Sydney) sent round here latest draft of her paper on Radio galaxies in the 2SLAQ LRG Survey.
This, coupled with noises coming out of Princeton, with an imminent Mandelbaum lensing paper, keeps everything nicely on the boil.

The Ross-Shanks Supercluster (2)

2006-10-26T15:08:00.000Z

Not to be out done by all the very pretty pictures floating around the Durham boys' blogs at the mo, I've stiched together a image of (what I'm calling the) Ross-Shanks supercluster, named after it's two maniac discovers.

Supercluster image.

The image is approximately 180 arcseconds on the side, is a composite created by the STIFF package (cheers Noz and JG) using imaging from the Suprime-Cam instrument on Subaru. The B, r' and i' bands are used.

The Ross-Shanks Supercluster

2006-10-23T20:30:00.000Z

w(theta) from AAOmega *finally* done (how the fook was that so hard to do?!?!?!)

Clustering/bias evolution was last weeks in-thing but still v. relevant.

Spiral LRGs in COSMOS - we shall see!!

Meanwhile, re-looking at the COSMOS data and doing a very basic wedge plot Shanks and I are claiming discovery of the Ross-Shanks supercluster at z~0.67 RA=150.05, Dec=+2.5. So there.
(Let's not worry about the fact the nearly every major telescope in every EM-band has been pointing at this structure for the `proper' COSMOS survey.... ;-)

What's it gonna be? So hold me tight and don't let go!!

Radio cross-correlation and VVDS

2006-10-19T13:14:00.000Z

Managed to finished off the 2SLAQ LRG-Radio Source cross-correlation for Sadler (Sydney) yesterday. Looks as if the Radio sources are more strongly clustered than the LRG autocorrelation, though, as always some more checks are needed. However, as suggested by Croom (Sydney), this can lead (via some assumptions!) to DM halo masses. V. interesting.

Also v. interesting was Meneux (INAF-IASF Milano, INAF-OA Merate) short seminar re-capping the recent results from the VIMOS VLT Deep Survey. Anyway, more about this later once I've considered the thesis implications (if any!!)

ill

2006-10-18T09:11:00.000Z

Sorry to report that there's not been much on the research front. Basically a cross between muchos faffing and lying in bed all of yesterday being a bit ill. :-(

My so-called friends.

2006-10-12T15:44:00.000Z

Hmmmmmmmm.

It turns out that Prof. Stephen Hawking did not phone me today. Gutted. It turns out I was the butt of a very cruel practical joke from my so-called friends. (These are the same "friends" that forced me to run a half marathon the other week....)

Anyway, let it be said that a couple of bored postgrads, with too much time on their hands, a Mac, telephone and a "sense of humour", can do a pretty good SH impression. You have been warned.

In other news, pretty pictures are on hold at the mo as I return to the w(theta) issue. However, this time it is for our AAOmega data and I'm reminding myself how much I love/hate the ol' SDSS CAS.

WOW!!

2006-10-12T11:21:00.000Z

WOW!!!

I've just received a phonecall from none other than *THE* Professor Stephen Hawking!!!
Just made my blindin' day.

He said he was looking for new personal assistant and I had been highly recommended by Prof. Shanks.

However, he also said my work was a pile of **** and that I should have a "Nice Day".
These last two comments have obviously made me suspicious it wasn't him afterall :-(

stiff in batch mode?

2006-10-11T21:18:00.000Z

Slow day for numerous reasons and interuptions - grrrrr!!!!

Seems like "the mask" for the S11 field doens't make a huge amount of difference, but always nice to do things properly. Would be cool to get a decent correlation length but how exactly am I gonna work out the errors??

Need to get stiff working in batch mode. Otherwise it's me combining Subaru Bri bands for over 100 z~0.7 LRGs. Ouch!

pretty pictures

2006-10-10T15:02:00.000Z

Had a good one the day.

The a.m. was spent getting the S11 data into the AAOmega xi(s) and I think I've just about managed to do this.

The p.m. was spent downloading public data from the COSMOS site and have proceeded to make a dozen or so pretty postage stamp pictures. Will continue with this endeavour tomorrow and would be v. sweet to have my piccys do some science for me....!!

cracked on

2006-10-09T20:53:00.000Z

Cracked on with the AAOmega clustering getting the first sensible real-space correlation function.

Had a two hour meeting with El Supervisor discussing ways to finish the thesis "in a flourish" and in 3 months. This didn't include redshift z~7 galaxies (sadly) but he did mention that I have enough material and it's a matter on too much stuff out there rather than too little.

Butterley (Durham) raised a good point late on, wondering how much astronomical data goes unused. We both suspected it could well be quite a lot.

submitted

2006-10-05T09:05:00.000Z

Thursday, October 5th 2006. 09:53. After just over 3 years of PhD work, The 2SLAQ Luminous Red Galaxy Survey: The 2-Point Correlation Function and Redshift-Space Distortions paper was submitted to MNRAS.

I then took a 5 minutes break to read about the BBC News website and then it was back to the grindstone.

Dr. Brown

2006-10-04T20:25:00.000Z

Just a quick post to say well done and a great big Aussie "Good on yer mate" to Tony.

After a (relatively short) 2 hour viva voce this a.m., The Bone emergerd unscaythed and with only some minor corrections. No doubt Walkabout, the new Freshers and most of Durham will also know all about this one by the end of the night!!

Numb Encore

2006-10-03T18:37:00.000Z

Good day. Convinced myself (and TS) enough about the w(theta) issues. However, Shanks (Durham) got fixedated on a couple of points at ~200 arcmin scales. Now, as usual, he makes a good point - that in physical scales, the 2SLAQ LRG is much wider than deep, so the w(theta) is as good an estimator as xi(r) - and so is another thing worth investigating, but not right now!!

new blogs!!

2006-10-03T10:56:00.000Z

Just a quick note to give a shout out to some recent blogs that have come to my attention.

The links should be updated on th right, so surf away and if there are any comments, queries or just general chat, as always, let us know!

The Blue Boy

2006-10-03T10:42:00.000Z

Monday. Pretty good progress made in the day (must have been something to do with El Supervisor being in the office all-day long doing CTIO apps!!) and am now reasonably convinced that there is no angular systematic in the w(theta). (I didn't think so before but evidence is always nice).

Tuesday. Had a couple of thoughts overnight about how to tidy-up a couple of things again re: the w(theta), Jon Loveday's comments and the Limbers formula stuff. Be so nice to get everything v. close by Thursday lunchtime.

2hours 5minutes

2006-10-02T07:32:00.000Z

Morning,

Just a quick early-doors post to let you know that the Great North Run was completed in said time. Superb day out, really capturing a lot which is wholesome, altruistic and generally good about the human spirit.

Gonna be a very busy week. Friday didn't see much getting done, apart from the first tentative steps to see if there is an angular systematic in the 2SLAQ w(theta). This would be very interesting to know and I think there's a (relatively) simple way to find out.

The LRG-Radio cross-correlation also is still waiting to be re-checked.

Apparently, all the new PhD students could arrive today. Time to be leaving me thinks...

back from London

2006-09-29T09:05:00.000Z

Just a quick early(ish) morning post to say Crain (Durham) and I are back from the Royal Society Communication Day.

We had fantastic time and felt the RS course itself was very well run and well worth the effort. More updates and piccys should appear in due course and over the weekend, both here and at the iccmofos.

However, it's right back into it this morning and there are more positive comments being received about the 2SLAQ clustering paper. Among several other co-authors who I'm chuffed to have on my first paper, Eisenstein (Arizona) is on-board which is a huge bonus, especially since this is the most cited astrophysics paper over the last year of so.

progress

2006-09-25T13:51:00.000Z

Afternoon all,

Just a wee post to let you know that Thursday saw a major breakthrough with the AAOmega clustering. A simple mistake in my coding (quelle surprise) was screwing everything up. I think I now have the proof the LRG clustering at z~0.7 is the same in strength as at more local z<0.3 redshifts (a la SDSS).

Friday saw the dentist, who has always been v. interest in my academic persuits, giving me teeth a clear bill of health. Though, it is very tricky to describe galaxy clustering in detail while "opening wide " and in the midst of a check-up.

Today, progress is finally being made on the LRG-Radio x-correlation though I have no major claims as yet.

However, thoughts this week are definitely turning to the small matter of 21.0824 km to be run this Sunday...

ASTRONOMY IN BUNG SHOCKER!!

2006-09-21T13:40:00.000Z

Bung taking is rife in astronomy - from PhD places to first year vivas all the way to the top. However, this reporter never even began to imagine the scale of the underhand deals that take place and at all levels of the game.

"Well, I've never been offered one, but how do you think I got to my position," laughed one senior astronomer, who for legal reasons can only be named as Prof. S.

"Oh sure," said one current PhD student, called Mr. RB in our investigations, "[Bill] Frith can get you a long way in this game." Mr. RB continued, "Also, I knew that since the person doing my interview was from Bolton, we could come to some sort of agreement." As a result, Mr. RB is now sailing into his second year as a postgrad.

One very well respected post-doc, who wished to remain anonymous, said the reason for the perceived corruption is that "it's because the stakes are so low".

Yet, since none of these allegations can be conclusively proven at the moment, the investigations have been put on temporary hold. However, it woud be fair to expect more news and revelations in the coming days, weeks and months.

Undercover

2006-09-20T09:59:00.000Z

After last nights Panorama programme, I'm going undercover to see how rife bung-taking is in astronomy. I have a feeling the results could be shocking. The investigation will start at the lowest rungs in the game (a.k.a. Shanks' PhD students) and aim to work it's way up from there....

In other news, I think I'm only a step away from working out an integral constraint on the 2SLAQ LRGs.

Still have the radio X-cor to do for Croom and Sadler (Sydney). D'oh.

I wonder if astronomy TACs take bungs??

2006-09-19T21:55:00.000Z

Well, I don't know if I'm trying to be an idiot but while there are fifty-one other things I should be doing, I'm sitting up, going late into the night writing Gemini and ESO VLT proposals. While I was told today that I need model predictions, a better science driver and essetially a 50m telescope with MCAO, in the Spirit of Shanks (an extremely rare single malt, aged >25 years),
I'm gonna blow the hatches and go ahead anyway.

Other activites today included replying to Don Schneider's (PennState) generally minor comments on paper. Other big name on board!!

Astronomy in Timbuktu

2006-09-18T11:54:00.000Z

(from Friday, Sept 15th 2006)

After a day of not achieving masses, had a small break-through late on. For some (still very unknown reason) the DRs in the COSMOS field are "dodgey". However, doing a Peebles-Hauser (1974) DD/RR calculation will bypass this current problem and the resulting xi(s) estimate is perhaps believable. Yay!

Had a v. interesting historical astronomy talk by Thebe Medupe (Cape Town) all about African astronomy and how dominant it what European's call the Middle Ages (~11th = ~ 15th Centuries). Timbuktu (in Mali) was essentially a large oasis of scholars studying astronomy, mathematics and law.

A-ha

2006-09-13T15:38:00.000Z

Think I've fixed my AAOmega w(theta) Full/COSMOS/d05 field discrepancy. All 3 w(theta) estimates now agree (obviously within the errors!) and as usual in astronomy, solving one puzzle opens the door to several others. So I ask myself, if the angular and radial masks of said fields are sound, why do I continue to get a very flat xi(s) estimation??

Been re-reading Masjedi et al. again. I really like this paper and the conclusions about the v. low LRG-LRG merger rate still has me thinking... (AAT deadline Friday 1pm...)

The d05 and COSMOS field

2006-09-12T13:41:00.000Z

After doing a pretty basic but robust modelling of the N(z) of the data in the d05 and COSMOS field, I think I might have my first reasonable approximation of a xi(s) for the riz AAOmega data. There still seems to be (serious) issues regarding the COSMOS field (and subsequently the whole sample) but the d05 data is looking v. promising.

Among the telescope deadlines, I'm gonna to try and do a little bit of work for Croom and Sadler (both Sydney) on the radio clustering of the 2SLAQ LRGs this week.

k+a galaxies

2006-09-08T12:05:00.000Z

Well, the 2SLAQ Survey is really firing on all cylinders now. Roseboom et al. appeared on the pre-prints this a.m. The way I read it, the bottom line is that "simple" star-formation activity (which manifests itself in the appearance of k+a and em+a LRG spectra) is not sufficient to explain the bulk of mass growth in early types from z~1. Thus "dry" mergers (i.e. mergers which have very little gas associated with them e.g. Bell et al. 2005) probably play a major role in this early type mass build-up.

As far as my stuff goes, the current wall I'm trying to walk around is that of creating a decent mask for our March (!!) AAOmega data. I thinking of giving up on the "bullseye" idea and going back to simple squares.

Have a good weekend.

CVs

2006-09-06T12:55:00.000Z

Just been to a v. good careers talk from Alexander (Durham) and was thinking I'd probably
want a CV like this at some point in my life.

Nice.

BTTF numbers

2006-09-05T10:33:00.000Z

I'm sure some other physics student has done this simple calc but:

Rest Mass of a De Lorean DMC-12: 1230 kg (equivalent to 1.107 x 10^20 Joules).

Kinetic Energy of said De Lorean travelling at 39.33952 ms = 934,415 J

Therefore, total energy of the moving car = ~1.107x 10^20 Joules.

Energy of lightning bolt that struck the clock tower = 1.21 Gigawatts.

At this point I get confused. How does a flux capacitor work??

It's been a while....

2006-09-04T16:45:00.000Z

Good morning everyone!!

So, after my month long hiatus (I was on my sell-out "Supenova" tour, but more about that later), the old blog might get going again.

Just a couple of wee bits to update you on. The z-space paper has gone collaboration wide this
afternoon. Publish and be damned some might say.
The Sloan had a trio of "biggees" last week, here, here and here.

What else? Well the "bias" chat in these papers has led to some possible ideas for PATT applications and the ol' KDC idea is still a possibility (however distant and infeasable it might be).

On a work related but non-cosmo note, rain (Durham) and I have booked our accomo for our RS Media Day jaunt. Just have to polish up that 4 minute blockbuster of a speech now!

Things you should know...

2006-08-02T15:55:00.000Z

1) Jim Peebles is the definition of awesome.

2) LRGs are a long way from being "sorted" and a "well understood" population of galaxies.

3) Comic Frontiers.

4) The "confetti to gold" story of Space Shuttle launches is actually sorta true!

5) It's raining quite heavily in Durham. And we're on the Prince Bishop this evening...

LOST LUGGAGE UPDATE

2006-07-17T11:14:00.000Z

As I'm sure a few of the loyal blog readers will be aware, on my return from Germany, British Airways managed to mis-place by rucksack. However, after some very nice work by a close associate of mine who was down in Heathrow last week, the said backpack was recovered and is now back in my possession. WHOO HOO!!! It was still in the "Misplaced Luggage" hold at Terminal One and Lord knows if I would have ever seen it again apart from the brilliant spot that led to its recovery.

So tips for not losing luggage: 1) Place a name/address tag inside the bag. 2) Don't pack 1 litre Munchen stein beer glasses that look like a bomb or a dodgey coke package and 3) Don't fly BA (at least until they
get their act majorly together at Terminal Five....)

Phew! It's a Scorcher!!

2006-07-17T11:05:00.000Z

Global warming does exist. We have know about it since the early 1970s. Anyone who says, or worse, believes otherwise is either in the pockets of the oil industry or still believes Omega_Matter = 1.

After having thought (for the umpteenth time) the redshift-space distortion paper was finished, Shanks still thinks it is worth trying to fit some more double power-laws to the w(theta) or wp(sigma)'s. Holey-shmoly.

The Shuttle is due to land in a couple of hours or so.

I am now 26. By hook or by crook I will get my PhD finished when I'm this age!!

"Final" comments

2006-07-05T10:00:00.000Z

The redshift-space distortions paper is finished and I'm waiting for Shanks' (Durham) "final" comments. Not before bloody time.

Sadler (Sydney) has emailed her draft paper on Radio Properties of the 2SLAQ galaxies and evolution of the Radio LF. Potentially a couple of nice conclusions if everything holds with implications for AGN and good ol' feedback. Well let you know more when I do!

velocity dispersions

2006-06-30T09:11:00.000Z

Still trying to figure out exactly why turning fixing a value for galaxy clutser velocity dispersions has a different effect than letting it float and finding a the best-fit minimum value. Puzzling. Very puzzling.

Shanks (Durham) gave Observers' Lunch today on "Lensing and the CMB". Although I've always liked his maverik style and the questioning of fundamental idioms - e.g. is the search for the dark matter particle like the search for the neutrino (successful) or the EM ether (unsuccessful but then leading to SR)?? - I have trouble with the current lensing model than desperatly struggles to reproduce the CMB power spectrum. Fully admitting that there could be a number of different things going on with respects to foregrounds (SZ effect and
the like) which have to be brought under better control.

In non-astronomy news, Germany play Argentina today in Berlin for a place in the World Cup Semi-final. Does it really seem a week ago?

We're Back!

2006-06-27T21:19:00.000Z

Dear Loyal Readers,

Well, I'm back from Munchen and Berlin (sans baggage*) and having had an awesome time with the Brazillian samba beats, Tunisian horns and Bavarian spaceships it has been back down to earth with a bump. Which is a kinda weird thing considering the objects we're studying.

Not much has happened over the last couple of days. I've finally begun to decipher da Angela's distortion chi-squared code and have left a couple of things running overnight. We'll finally see how much difference the Hamilton and LS estimators *really* have...

Also helped Shanks on a piece for the AAO Newsletter bout our run in March. Curiously, they want it in Word format (WFT!!!) which has proved the most hassle.

Hawaii 5 0

2006-06-15T20:04:00.000Z

Dear all,

Once again v. sorry for the lack of posts of late, and indeed this will be the last one for at least a week.

Good news is that the redshift-space distortions paper is basically done, well at least my first version of it, and if pigs fly and Jose's code is okay overnight, we should be sending it collaboration wide presently. Hurray!

Two pretty decent talks this week Ellis (Caltech), Baldry (Liverpool John Moors) which I'd love to go into more details but that'll have to wait.

And AstroGrid workshop today. Had quite a good laugh but am still struggling even as we speak to get the workflows doing a simple simple task.

Anyway, have fun over the next week or so and speak later!

Cheers,
nic

ARGH!!!! (Part 2)

2006-06-12T21:47:00.000Z

ARGH!!! Just when I thought I was one step, one graph and \subsection{} away from completing the redshift-space distortion paper, I discover I've forgot to reset xi_sigma_pi_LS and I have correlation functions that are multiples of each other. Fook!

Anyway, it's so close now and the end of this week has to be a pretty hard deadline to get this done by - don't stand so close to me!!

Oooo, and Ellis (Caltech) is speaking tomorrow. Really looking forward to that and if Shanks (Durham) gets going - now that's a real Royal Rumble!!

In other news, I finally took home Mullaney's (Durham) home smoked bacon. Gonna go well with me eggs tomorrow!!

ARGH!! (Part 1)

2006-06-08T16:46:00.000Z

What is the co-moving distance of a galaxy with redshift z=0.3410 given Omega_M = 0.3 and Omega_Lambda=0.7 in a flat Universe???? Is it 939.45, 940.3 or 940.93 h^-1 Mpc???

Anyway, whatever it is, this has severly annoyed me today as just when I thought I was putting the final touches to all my graphs, there seems to be a slight issue with co-moving distances and co-ordinate transform. However, I really don't think (and really do hope) that this will have much, if any bearing on the final redshift-space measurements.

In other news, the DES is coming!! Both the CTIO and VISTA versions. Castander (IEEC, Barcelona) gave a comprehenisve seminar on the subject this lunchtime - but will this be competitive on the timescales we're talking about??

P.S. The network started having real problems last night and this post didn't published until this morning.

Royal Rumble

2006-06-07T10:09:00.000Z

In an attempt to satisfy a regular readers request for more Middleton (Durham) related stories, here is a paper from astro-ph yesterday relating to the spin of GRS1915+105. McClintock et al. (astro-ph/0606076) claim a much higher value for the dimensionless spin parameter (a > 0.98) than Middelton et al. (astro-ph/0601540).
However, I have it on very good authority that the Middleton group are "not convinced" and this reporter thinks a Battle Royale is on the cards....

In related, non-astronomy news, Middleton has agreed to an "Erg-off" with Shone (Durham).
Gentlemen, start your engines!!

paper

2006-06-06T09:32:00.000Z

Everything else is on hold until I get this paper DONE. There are a lot of tweaks I can still do but really have to push now to get it past Shanks.

Apologies

2006-06-04T16:08:00.000Z

Dear Loyal Readers,

Many apologies are due to the last week of non-posts. Sorry. Slightly ironically this is because I had a pretty productive week analysing my jackknife samples which ended up with a Omega_m-beta plot from Jose late on Friday evening. To summarise, at the moment a simple least squares fit to wp(sigma) and xi(r) I think favour a single power-law more (r_0 = 7.2+0.8-0.7, gamma = 1.78+0.14-0.10) but a double-power law cant be ruled out. Jose's first esimations from fitting the redshift-space distortions suggest Omega_M = 0.2, beta=0.5, velocity dispersion 400 km/s.

Other highlights of the week were another good Wednesday seminar from Ferguson (Edinburgh) talking about what we can learn by looking at very local galaxies (in this case M31 and M33) and if you see tidal stream features (M31 you do, M33 you dont).

Also, I gave a Observers' Lunch talk on Hopkins, Richards and Hernquist (astro-ph/0605678) "An Observational Determination of the Bolometric Quasar Luminosity Function" which makes some very strong but credible claims about quasar and black hole properties such as "birthrate" number and space density evolution, M* break-mass and "downsizing".

brightening up??

2006-05-26T14:37:00.000Z

Jackknifes are ready! Had a long discussion this morning with Biebly about what exactly the covariance is and how you calculate it. This was v. informative because now, not being satisfied that I know what IDL is doing, I'm going to modify some of my own code to work out the best-fit line with the covariances taken into account.

UEFA Co-efficients

2006-05-25T15:02:00.000Z

But first Luminosity Functions. There have been calls from Shanks to produce a LF for the AAOmega data. Now after having a wee chat with Wake, there are two levels to this. The first is that it is (relatively) easy to perform a 1/Vmax calculation and get a LF. However, this on its own isn't a great scientific achievement. What you want to do is compare this number and see how the LF evolves. This is the second level and comparing AAOmega LRGs to 2SLAQ LRGs could be done but the delta_lookback time is <1 Gyr which in astronomy terms is nothing. Comparing AAOmega LRGs to SDSS LRGs would be sweet but is going to be nigh on impossible.

Meanwhile, I've been figuring out how the hell UEFA work out their seedings in the European and UEFA Cup. Have a wee gander here.

www.talk107.co.uk

2006-05-24T18:00:00.000Z

I hate it when you run a code for three or four days and then discover you hadn't reset your RR counter and all your xi(s)'s tend to one at large scales. :-( Gutted. Hopefully fixed code and Bielby is running some of the calculations on his machine. Muchos Apprecieatas.

Wolfe (Chicago), of the Sachs-Wolfe affect, gave a enjoyable talk on Damped Lyman-Alpha (DLAs) systems in the Hubble Ultra Deep Field. Shanks is convinced that essentially Lyman-Break Galaxies (LBGs) are today's spirals at redshift~3. Wolfe talked about the (neutral gas?) threshold a galaxy has to be at before star-formation can take place and how all observations so far indicated a low SF density for DLAs (rho_star_dot for DLAs <10^-2.4 M_solar per year per Mpc^3 versus 10^-1.7 - 10^-0.8 M_solar per year per Mpc^3 for LBGs). This very low SF density then throws up problems for metal production ("DLAs are alpha-element enhanced) and heating-cooling rates in these systems.

All very interesting and a bit complicated!

Tomorrow: finish prepping codes for *final* xi(r) jackknifes (still worried bout the IDL linfit routine...)

B.T.W. I think I've found the best radio programme in the world: Drive-Time on talk 107 radio, 4pm-7pm. "Upping the Auntie with Simon Pia & Heather Dee". Superb for a New Town boy.

reminding myself

2006-05-23T17:05:00.000Z

This morning was spent looking at the 120 or so match-ups between GALEX and the 2SLAQ/AAOmega LRGs. Couldn't find any trend of FUV-NUV colour vs. redshift, but there again would you expect to?

This afternoon I reminded myself of the SQL queries I used when doing the S11 COMBO-17 comparisons.
Tomorrow, the jackknifes should be ready!

Hard Rock Hallelujah

2006-05-22T20:01:00.000Z

Well, the computers finally came back online and got my jackknife program running. Sheesh, I could have done this AT LEAST A YEAR AGO and have to ask myself why I didn't. Anyway, well take all 31 jack-knife samples all the way to xi(r) and then work out the covariance from there...

Had a wee bit of "fun" playing with GALEX data. It's a bit odd that some of the nice GR1 SQL features (such as the link to SDSS DR3) haven't quite been upgraded into GR2. Anyway, will wait until the full AIS data is released.
First look there seems to be ~100 LRGs (2SLAQ and AAOmega) with GALEX FUV and NUV imaging.

Anyway, if this astronomy malarkey doesn't work out there is always, sex, drugs and this.

The Morning Post

2006-05-22T08:20:00.000Z

So, as has been mentioned in other illustrious blogs (the Mofos), the computers were down over the weekend in the Durham Astronomy department. This has particularly annoyed me since I spent all of Friday modifying my code to run for 48 hours and to pick up the results this a.m. What compounds this situation is that the link to the FORTRAN compiler license is broken so I can't even re-compile my program and get it going again.

And it is blooming miserable outside. Fud.

hee hee hee

2006-05-19T21:43:00.000Z

Some have commented this blog is a bit "dry". Well, screw you guys.

However I, to quote the Constitution "shall from time to time" deviate from my "research" and post a Challenge on this blog. ALL commers welcome and a small prize (possibly in the shape of a 567 ml glass of alcoholic beverage) shall be offered to the winner*.

So, this weeks challenge is very very simple:

Please send me the best 3 websites in hyper-space**

I shall be looking for: humour factor, geek factor, "Can-I-send-this-to-me-Gran" factor as well
as that mysterious X-factor (WETF that is).

All enteries get "Honourable Mentions" and the Winner gets said pint.
And hey, if you are the only entry, well, de fault are the two most beautiful words in the English language.

Good Night and Good Luck!!

Conditions:
The judge's decision is final. Share prices can go up as well as down.
*If you do not live in the UK, or do not drink, I shall post you £2 equivalent in UK Sterling to your desired address.
**Hyper-space is an abstract idea per se so don't spend too long looking for in it or for it...

Eto'o 76, Belletti 80

2006-05-17T21:29:00.000Z

Made some progress today on the npt code. Fook, this is beginning to be one of "those" weeks but I just don't have many more weeks left.

Conselise (Nottingham) gave a very interesting (though not to say I believed it all) talk this afternoon on morphologies, stellar masses and merger rates of "massive" (10^10-11) galaxies. Bit tired right now (ah....) so will have a think about this some more and report later.

another frustrating day

2006-05-16T20:29:00.000Z

Why, oh why, oh why, oh why?!?!?!?!? Just when I thought it was a simple case of typing "FORMAT" instead of "format" (classic) I then begin to realise that there is something else up and the bloomin' DR counts are still screwy. I'm satisfied my correl_five code is correctly outputting numbers, Wake is satisfied (and I am too) that the npt is fine but what then is happening when I compare the random-random distributions and find the number of DR pairs are less than DD pairs. Oh dear me. Bet The Doctor never has this problem and that's why he gets so much done.

Anyway, "first" thing tomorrow, my own (x,y,z) random points, 1000 and then 10,000 of them and let's see where that leaves us. Sorry if this is turning into a bloan (cross between a blog and a moan).

Some more interesting papers today on the pre-print server.
Cimatti et al. (astro-ph/0605353) commenting on the build-up of mass from z~1 after re-examining rest-frame B-band COMBO-17 and DEEP2 luminosity functions (LFs) of early-type galaxies. From the abstract, "At each redshift there is a critical mass above which virtually all ETGs appear to be in place, and this fits well in the now popular "downsizing" scenario. However, ``downsizing'' does not appear to be limited to star formation, but the concept may have to be extended to the mass assembly itself as the build-up of the most massive galaxies preceeds that of the less massive ones". This seems to fit quite nicely with Wake's recent result and will be v. interesting to hear how it fits in with Conselise (Nottingham) talking tomorrow.

The other paper that caught my eye and that I read was Rigopoulou et al. (astro-ph/0605355) and the discrepancy in the last graph between recent z~3 LBG observations and the ol' theoretical models.

"Eloi, Eloi, lama sabachthani?"

2006-05-15T18:40:00.000Z

What a frustrating day. Have realised that the "all-singing-all-dancing" npt code doesn't seem to calculate xi(sigma,pi) correctly!! There seems to be an order of magnitude difference between DR pairs which leads to ~unity values of xi and high wp(sigma)'s. ARGH!!! Really not sure what to do. Just when I thought there was only a couple more bridges to cross, this happens!!
If I cannae figure oot what's up with the npt code for the DRs (and RRs????!) then I might just have to resort to what I wanted to do this time last year!! Fook!!!!

On the wires today were Padmanabhan's (Princeton) and Blake's (UBC) photo-z LRG Power spectra papers (astro-ph/0605302 and 0605303). They are basically looking at exactly the same things (angular power spectra with LRGs, photo-z's being estimated from training sets and then some "fancy maths" to get the 3D power spectrum). Well, if correct and they have a handle on all their systematics, photometeric calibrations and other selection issues, then these are (very) powerful pieces of work. However, what I don't understand straight off the bat is how, if you are claiming, at best delta_z = 0.03 on your photo-z, can you then split your sample into bins of 0.05 width (e.g. 0.45 < z <0.50) ????

That goal was perfection

2006-05-14T15:20:00.000Z

Oh dear. It is grey and raining outside on a fairly relaxing and very quiet Sunday afternoon.

Thursday and Friday were spent continuing working on xi(sigma,pi) refinements and lo and behold, Shanks read my paper and made some good useful comments. After finishing off a couple of things on Monday morning, it'll be full head steam ahead as I feel we really are close but just have to take a deep breath and finish it off.

Have just been checking out various astronomy websites (Spitzer, GMT, ESO) but have very little of any value to report. Sorry.

understanding perldl

2006-05-10T21:38:00.000Z

Hmmm. Not my most productive day ever. Spent the morning going back over the .pl scripts I have to calculate covariance matrices and correlation functions to make sure all the errors tallied to the right bins. They did and I do essentially now have (for the first ever time) a xi(s) for the entire 2SLAQ LRG Sample 8 with proper jackknife errors. Bout ruddy time too.

Lunchtime talk was given by the IPPP and the statement to discuss was "WMAP3 rules out inflation models with potentials greater than or equal to phi^4." Hmmmm, interesting but didn't quite understand (like many of the audience) what assumptions go into making this claim. Also "racetrack" potentials are still favoured. However, it does seem as if n_s is red...

Spent most of the afternoon reading-up on basic astrophysics and jotting down a few things for my "Employmen Information Package".

Shanks in Nottingham today. Nuff said.

Tomorrow am: Bulk up jots and re-jig Statement of Research Interests.
Tomorrow pm: FITS files and sodding xi(sigma, pi) (leftover from today!)

Serbia and Montenegro vs. Ivory Coast

2006-05-09T20:14:00.000Z

I officially published the AAOmega LRG Pilot Catalogue today. Well, at least sent a file with 1360 objects observed by AAOmega with positions, redshifts, "qops" and magnitudes galore to those in Australia that have been requesting said data. Nice to have been in charge of that from conception to publication. Now to write it up properly!! Bielby is working on the ELGs from the Pilot run and we should have those by the end of the week.

3 really nice contributions to "Observers' Lunch" today. Alexander (IoA -> Durham) talking about Chandra 2Ms exposure, obscured AGN, dusty tori and Spitzer galaxies. Mullaney giving us a first glimpse into what some of his first year work has been on (AGN spectra modelling from radio to X-rays) and Schurch reviewing the discovery announced at NAM2006 of a new type of pulsar which no-one has any idea about. Cool.

Still waiting for feedback from Shanks....

Tomorrow: 1) xi(sigma,pi) .fits files and 30 calculations of wp(sigma) 2) Employment Information Package!!

From Paris to Berlin

2006-05-08T20:31:00.000Z

....and every disco I get in.

Produced a nice graph of Poisson errors vs. Jackknifes today. Very comparable on "small" scales (<5 Mpc) but then the Poisson errors (badly) underestimate the spread on the larger scales and my hump of 3 points at ~40 Mpc have the largest errorbars. Superb.

Been looking at the COMBO-17 galaxies we got redshifts for. Looks like there could be something here as the COMBO photoz's seem to be systematically smaller than the spectroscopic AAOmega qop 3's.

Shanks did not read my paper over the weekend. Maybe tomorrow...

Sunday evening blues

2006-05-07T17:54:00.000Z

Glorious Friday was spent running the npt code for me deprojected correlation function jackknifes. Left the RR case running over the weekend.

Lunchtime talks were by Angulo and Helly, who talked about BAO predictions from semi-analytic models ("ICC1340") and (lack of evidence for) cirlces in the CMB and a non-infinite Universe. Anyway, nice to know that we live in a Universe which is at least 26 Gpc big (what that means exactly I'm not entirely sure).

Gave the latest draft of the paper to Shanks. Let's see if he reads it over the weekend....

Fortuna Imperatrix Mundi, Fortune Plango Vulnera Una

2006-05-04T20:34:00.000Z

I did some maths today. Begun to get my head around covariance and correlation matrices and that Numerical Receipes book is a good as anything. Feel I understand now where all the covariances link in, at least as far as the "Normal Formulae" go.

Also - and I apologies to those that think I am a heathen for only doing this now - had my first good experience today with IDL. Thanks Norris and da Angela (both Durham). As such, have a nice least squares function waiting for me tomorrow!

However, late this evening figured out why I've been so worried about this whole thing. Essentially I'm still only working out variances and covariances on the redshift-space correlation function (de-projected or otherwise). However, you still have to collapse/integrate this to get wp(sigma) and then INTERPOLATE to get the real-space correlation function. Argh! And how the errors carry through is anyones "guess".

bruised feet

2006-05-04T08:14:00.000Z

Went back to editing/tidying-up and writing the redshift-space distortion paper today. In the process of do so and re-doing an N(z) histogram, discovered that I could improve the random catalogue redshift distribution so it matched the LRG data much more closely. Achieved this and re-calculated (once a friggin' 'gain) the correlation function. Have stated to look into the errors again and how to manipulate the covariance matrix but that can be Thursday job.

hiding behind my jumper

2006-05-02T22:08:00.000Z

More work on the thesis today, which consisted of re-writing the ol' paper. Realised that the logic in the Results section is a bit screwy so had a go at re-ordering this into a sensible progression.

Not much more news. Wasn't a slow day as such, just really "erg-ging" so tae speak. Had an IPPP talk at lunch which was kinda interesting again about WMAP3 but had heard most of the stuff before. Still always worth going to these things as you do always tend to learn or reinforce something.