instruments that trace large-scale mass distributions

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Rich Savage
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Joined: September 28 2004
Affiliation: University of Warwick
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instruments that trace large-scale mass distributions

Post by Rich Savage » October 08 2004

Hi folks,

What current and forthcoming instruments do/will do a good job of tracing the universe's mass distribution? Here are a few thoughts, questions and suggestions, just to get the ball rolling:

ASTRO-F (forthcoming). The far-IR all-sky surveyor being launched by the Japanese next summer; it'll see of order a million galaxies out to z>1, using 6 observing bands.

Sloan Digital Sky Survey (current)

AAOmega spectrograph (forthcoming) The replacement for 2dF (and other instruments on the AAT), it should be able to do million-object surveys over most of the southern sky.

What can you do with WMAP (Planck) data?

Other big galaxy surveys.

cluster surveys?

Lensing surveys?


With apologies for anything I've missed - of course, the best way to remedy that is to post the correction, along with details of whatever it is!

All contributions welcomed.

Best regards,

Rich

Sarah Bridle
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Joined: September 24 2004
Affiliation: University College London (UCL)
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Galaxy surveys

Post by Sarah Bridle » October 08 2004

Hi Rich,

Imaging surveys coming up, all of ~5000 sq degrees, ~2008 -10. Could all be classed as galaxy surveys, cluster surveys and weak lensing surveys (ie. analyse the same imaging data in various ways).

DES (Dark Energy Survey) http://home.fnal.gov/~annis/astrophys/deCam/

PanSTARRS

DarkCAM, and optical camera for VISTA.

Also KIDS seems similar although I know less about it.

Longer term you have LSST and SKA.

Ongoing is CFHTLS.

Sarah

Rich Savage
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Joined: September 28 2004
Affiliation: University of Warwick
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Re: Galaxy surveys

Post by Rich Savage » October 08 2004

Sarah Bridle wrote:Imaging surveys coming up, all of ~5000 sq degrees, ~2008 -10. Could all be classed as galaxy surveys, cluster surveys and weak lensing surveys (ie. analyse the same imaging data in various ways).
Sarah
Hi Sarah,

Thanks, they all look really interesting! UKIDSS is a near-IR survey starting next year, on UKIRT. They're going to do five surveys, covering a total of 7500 square degrees in the northern sky. Their website http://www.ukidss.org/ says its basically the near-IR version of SDSS. Indeed, I think it's covering 4000 sq. degrees of the same sky as Sloan.

I have a question about weak lensing: what are the major constraints on doing this with suvey data? What sort of resolution do you need, do you know?

Best regards,

Rich

PS Ooh, just remembered I was going to mention WISE (Wide-field Infrared Survey Explorer), which is an all-sky mid-IR satellite that NASA are proposing to do. Not sure what stage of funding it's at, but I've found the following website useful:
http://www.astro.ucla.edu/~wright/WISE/

Bruce Bassett
Posts: 26
Joined: November 24 2004
Affiliation: SAAO/UCT

instruments that trace large-scale mass distributions

Post by Bruce Bassett » November 25 2004

Hi Rich,

One other nice survey is KAOS - mainly a dark energy experiment using baryon oscillations but will also get of order a million galaxy redshifts out to z ~ 3 so will allow us to study the evolution of the matter power spectrum and the Hubble constant as a function of redshift.

Two KAOS websites:

Current flash version (still in development):
http://www.dsg.port.ac.uk/~bruce/kaos/ - (needs a reasonable connection)

Original NOAO web site (a bit out of date but lots of technical details including the purple book): http://www.noao.edu/kaos/

Cheers,
Bruce

Rich Savage
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Affiliation: University of Warwick
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Re: instruments that trace large-scale mass distributions

Post by Rich Savage » November 26 2004

Hi Bruce,

*reads links*

Wow, that looks really impressive! I remember Bob (Nichol) has mentioned it before, when he's popped by to Sussex :-)

This might be a daft question and/or one with an answer somewhere in the purple book (in which case I apologise in advance!), but would it be feasible to do a huge area (say 5-10 thousand square degree) survey of targets that are really quick (say of order and hour) to get spectra for. I have no idea if such target a target list would exist (although there will be an awful lot of large area coverage in the next few years), but if it did then I guess that would give you 10 million objects out to redshifts of a few tenths?

Best regards,

Rich

Bruce Bassett
Posts: 26
Joined: November 24 2004
Affiliation: SAAO/UCT

instruments that trace large-scale mass distributions

Post by Bruce Bassett » November 27 2004

Hi Rich,

So lets consider a 10,000 sq degree survey with redshifts out to say z < 0.5 with 10 million redshfits....

As you say, target selection is going to be a real issue but even more would be the scientific motivation for such a survey. SDSS will have about this area with of course much lower densities. So you would need an application that required the much higher surface density of galaxies.

Increasing the surface density beats down shot noise but the gains are fairly small beyond the SDSS density I suspect.

Beyond KAOS there is SKA of course, which will get every galaxy out to high redshift (of order 1 billion redshifts if I remember right).

Cheers
Bruce

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