Re: Dark Energy Project First Light

[droege@snapmail.us]

Chris and all,

Just because I go to meetings and sit through the theory discussions does
not mean that I understand it.  I have the comfort that most there could
not move a signal from a telescope to the control room.

OK, my limited understanding.  It is like the cosmic microwave background.
 One does a detailed survey looking for structure in the nearly smooth
microwave background to learn about the big bang.

For dark energy one does the same thing only looking for the distribution
of galaxies by color.  We will be covering the same sky that a survey at
the South Pole is doing at the far infra red.  OK, I could be 100% wrong. 
This just from siting through meetings.

Tom Droege

OK, I copy here the material from the web site:

The Dark Energy Survey

    * Send this page to somebody
    * Print this page

Is the dark energy a cosmological constant?

Context

The discovery that the universe is accelerating, not slowing down from the
mass it contains, is the surprise that sets the initial research program
of 21st Century cosmology. The Dark Energy Survey is a next generation sky
survey aimed directly at understanding this mystery. Our quarry is the
dark energy, the reasons the universe is accelerating.

Instrument

We will build an extremely red sensitive 500 Megapixel camera, a 1 meter
diameter, 2.2 degree field of view prime focus corrector, and a data
aquisition system fast enough to take images in 17 seconds. The cage
containing the system mounts at the prime focus of the Blanco 4-meter
telescope at CTIO, a southern hemisphere NOAO telescope. The instrument
will become a general user instrument, available to the astronomical
community. We will use it to conduct a large scale sky survey.

Survey

Over 5 years we will use 30% of the available time on the telescope to
pursue a high precision multi-bandpass wide area survey, designed to
produce photometric redshifts from 0.2 < z < 1.3. The survey g,r,i,z data
will cover 5000 sq-degrees, with 4000 sq-degrees overlapping the
Sunyaev-Zeldovich CMB survey being conducted by the South Pole Telescope.

Science

Our 4 science goals aim at extracting cosmological information on the dark
energy from 1) cluster counting and spatial distribution of clusters at
0.1 < z < 1.3, 2) the shifting of the galaxy spatial angular power spectra
with redshift, 3) weak lensing measurements on several redshift shells to
z~1, and 4) 2000 supernovae at 0.3 < z < 0.8.

Impact

The signature of dark energy being a cosmological constant is that the
dark energy density remains constant while the universe expands;
technically that w=-1 and that dw/dt = 0. We aim at a 5%-15% precision
measurement in w from each of our experiments, and a 30% measurment in w'.
Combined, they provide both stronger constraints and a check on systematic
errors.

Created by annis


>
> Tom,
>
> You get an award for the subject line.
>
> Just happens I'll be out for beer Wends night at the local
> microbrewery.
> I'll tell everyone they are at the West Coast
> Internet virtual "Dark Energy First Light celebration".
> You can tell the people at your end that there are some
> guys out in California that you don't know who are
> calibrating.
>
> I figure I'm not the only one wondering how you are going
> to photograph dark energy.  Could you post a 15 second exective
> summary on how they get from dark energy to IR photons?
> I'm sure once you have the photon everyone on the TASS list would
> understand.  It's that first step that seem inpossible
>
> --- droege@snapmail.us wrote:
>> The Dark Energy Project at Fermilab has seen first light using Mark
>> IV
>> electronics.  To celebrate, I am having a First Light beer and pizza
>> party
>> at the Tass H location Wedmesdau night.
>>
>> If any of you active tass members are nearby I would like to invite
>> you to
>> join the party and meet the astronombers and physicists involved in
>> this
>> monster camera project.
>>
>> The camera will contain about 64 2k x 4k IR sensitive CCDs.  If you
>> would
>> like to come, plese reply and I will give you directions.
>>
>> Tom Droege
>>
>>
>
> Chris Albertson
>   Home:   310-376-1029  chrisalbertson90278@yahoo.com
>   Cell:   310-990-7550
>   Office: 310-336-5189  Christopher.J.Albertson@aero.org
>   KG6OMK
>
>
>
>
> __________________________________
> Celebrate Yahoo!'s 10th Birthday!
> Yahoo! Netrospective: 100 Moments of the Web
> http://birthday.yahoo.com/netrospective/
>
>