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Re: An update on the french meeting
Dear all,
On 17-Jul-01 JJ Kavelaars wrote:
> If one of the patches is 10x10 then
> I think there shouldn't be any additional patches needed.
>
As it was discussed in Paris, the 10x10 is NOT
a WL request, but a request from clusters (2 pt clus-clus correlation
function) and those looking at very large scale on galaxy distribution.
So the 10x10 deg^2 and 4 6x6 deg^2 are independent specificications,
with different scientific goals.
WL DOES NOT request angular scale larger than 6 degrees and I showed
that:
- beyond 6 degrees systematics largely dominate over the cosmic
shear signal, so signal on scale larger than 6 degrees is not possible
to reach , even assuming improvment of the shear measurement by a factor
larger than 3 (this is the limit we fixed as possible improvement based on
realistic assumptions from the imrpovmenets over the period 1993 to 2000)
- beyond 6 degrees the signal on the power spectrum from kappa is
totally dominated by cosmic variance.
- the power spectrum of cosmic shear contains useful informations
on cosmological scenario (lambda, effective quintescence, SUGRA or
RP quintesence fields) only on scale smaller than 6-5 degrees down to
arcminute scales.
- 4 6x6 vs 10 x10 is BY FAR much better for the cosmic variance,
so WL does not want to switch from 4 6x6 to 10x10 deg^2 field. In
term of cosmic variance that would be a big mistake.
All the best
Yannick
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PLEASE NOTE: NEW OFFICE AND PHONE NUMBER: April 10, 2001 [NEW CHANGE!!]
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Yannick Mellier Tel : (33) 1 44 32 81 40
Institut d'Astrophysique de Paris Fax : (33) 1 44 32 80 01
98 bis boulevard Arago Switchboard: (33) 1 44 32 80 00
75014 Paris Office : 210A (2nd floor)
France
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