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Optical

Page history last edited by Olga Melnyk 6 years, 4 months ago

Page maintained by: Pompei E., Elyiv A., Melnyk O.

 

OPTICAL OBSERVATIONS

 

Northern field (LSS field)

 

The northern field has been observed by several ground and space based facilities.

Table below contains the observations with main parameters and coverage maps.

Also we provide a link to the data, when publicly available. Details see in the footnotes.

 

Survey

RA (J2000)

DEC (J2000)

Wavelength

Coverage

deg2

Depth

5 sigma

mag (AB)

Availability/

[name of table in DB]

Relevant paper

Map

CFHTLS W1

02:25:59.00

-04:29:40

u'

g

r

i

z

21(1)

25.3

25.5

24.8

24.5

23.6

Y(2,7)

CFHT Field A(3) 

02:22:24.62 -03:15:38.27

g

r

z

0.4

26.8

26.3

24.8

Y

CFHT Field B(3) 

02:26:14.23 -03:15:48.87

g

r

z

0.9

26.7

26.3

25.3

Y

CFHT Field C(3) 

02:16:14.47 -03:15:45.87

g

0.9

26.8

Y

Subaru

deep field

02:18:00

-05:00:00

B

V

R

i

z

1.3

28.4

27.8

27.7

27.7

26.7

Y

 

 

Ueda et al.

(2008)


SDSS DR8  02:25:59.00  -04:29:40 

u

g

r

i

25(4)

 

22.0

22.2

22.2

21.3

20.5 

Y(5)

 

 
HSC Wide (Deep) 02:25:59.00   -04:29:40  

g

r

i

z

25(7)(6) 

~26.0 (27.0)

~26.0 (27.0)

~26.0 (27.0)

~26.0 (27.0)

~26.0 (27.0)

Planned  

 

(1) full W1 consists of 72 sq. deg

(2) DR7 is publicly available

(3) A,B,C fields are not reprocessed in the last CFHTLS release

(4)SDSS DR8 covers all LSS field
(5) Only photometric information is available, the spectra will be released in DR9 (July 2012)
(6) The Wide survey is a part of 1200 deg2 survey, the 7 deg2 Deep is a part of LSS
(7) Public photo-z are available at  http://www.cfhtlens.org/

 

Some more info on the CFHT new data:

 

CFHTLenS photo-z's have been optimized for weak lensing. The stacks are mean and the images are PSF homogenized so that gives a lower outlier rate. The masks are quite conservative, but really accurate.

Magnitude limit of the photo-z analysis: i'AB ~ 24.7.

Limitfor trusted objects: i'AB < 22.5

Object analysis limited within the photo-z range: 0.2 < z < 1.3

Reference paper: Heymans et al., 2012 

 

CFHTLS-T0007 is quite well documented and for galaxy studies, it has to advantage to have been extensively tested from previous release: star/gal separation, galaxy clustering. It also includes some holes that were previously missing (and still missing in CFHTLenS). Other important points:

The photometric calibration has been improved since previous releases.

The comparison with SDSS gives an offset in u of -0.05, in gri of 0.01 and in z of 0.02.

The rms compared to SDSS is below 0.01 in all bands, which gives a very homogenous photometry across the field. 

For i < 22.5, sigma = 0.04(1+z) and the outlier rate is 5% up to redshift 1.0. 

The release is well documented and for *galaxy studies*, it has to advantage to have been extensively tested from

previous release, in particular for star/gal separation and galaxy clustering. It also includes some holes that were previously missing (and still missing in CFHTLenS).

Access to photo-z catalogues: here

IMPORTANT: Read the documentation file FIRST!!!

 

 

 

Southern field (BCS field)

 

The southern field has a (36.9o)2 of completed optical imaging in 4 filters. In this table, a summary of the observations, their depth and the location where the data can be retrieved is given.

BCS region has been built into coadds tile by tile where each tile corresponds to a 36'x 36', and these tiles are on 34' centers, i.e. 2' overlaps between neighboring tiles, see maps below. 

 

Survey

RA (J2000)

DEC (J2000)

Wavelength

Coverage

deg2

Depth

5 sigma

mag (AB),

exp. time (s)

Availability/

[name of table in DB]

Relevant paper

Map

BCS

23:30:00  

-55:00:00

g

r

i

z

25(7)

24.75

24.65

24.35

23.05

Y

[bcsru

Menanteau et al.

(2009) 

Desai et al. (2012)

see more here

DES 23:30:00   -55:00:00 

g

r

i

z

25(8) 

25.7, 800 

25.1, 800

24.7, 1000
23.2, 1000

23.0, 500

N

 
DECam 23:30:00  -55:00:00  

g

r

i

z

 

 26.0, 1500

25.5, 1600

25.5, 4000

25.0, 8000

N  

 

(7) Full coverage is 29 deg2 

(8) part of a 5000 deg2 survey

 

 

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