Transcript Leiden Oktober 2005 - Royal Observatory, Edinburgh

Surveys of high-z galaxies and galaxy clusters
with Herschel and SCUBA-2
Eelco van Kampen
University of Innsbruck, Austria
Dust emission: far-IR & sub-mm
PACS SPIRE
Dusty star-forming
galaxies emit much
of their light at IR to
mm wavelengths
Stars
Figure compiled by
Mari Polletta
r
Dust
IRAC
MIPS
SCUBA-2
SHADES: SCUBA half-degree survey
2 fields – Lockman Hole & SXDF @ 850 micron
120 sources with unbiased (deboosted) flux densities
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Estimating the angular correlation function w()
DD  2DR  RR
w(θ) from the Landy & Szalay (1993) estimator:
RR

Lockman Hole
SXDF

Kent reduction noise maps
Random catalogues from the noise maps
S > 5 mJy
Procedure:
1. generate a uniformly distributed point source distribution
2. assign a flux according to number counts of Coppin et al. (2006)
3. add random (Gaussian) noise using the noise map
4. keep sources in the random catalogue with S > 2.5σmap
Random cat. + SHADES cat.  w(θ)
DD  2DR  RR
RR

S > 5 mJy

Lockman
S > 6 mJy
Kent reduction data only
Fitting to

DD  2DR  RR
RR

non-linear 2-fitting using the Levenberg-Marquardt method


the fitting includes the integral constraint taken from a look-up table

fitting functions are the angular correlation function w() = (/A) and the
sky-averaged correlation function:
2

w ( )  2  w( ) d
 0



the sky-averaging produces correlated errors, which is taken into account
by using the full covariance matrix to construct an alternative 2-statistic
SHADES clustering measurement
Lockman >6mJy
SXDF >6mJy
Large dots and solid line (fit) for the angular correlation function w(θ)=(θ/A)
Stars and dashed line (fit) for the sky-averaged angular correlation <w>Ω(θ)
Lockman: A = 11.0" +/- 8.7"
 = 0.76 +/- 0.31
SXDF: A = 27.4" +/- 14.7”
 = 0.91 +/- 0.43
(both estimates from the sky-averaged angular correlation functions)
Model-data comparison for SHADES
Fit to slope and
amplitude for 25 mocks
for four different galaxy
formation models
van Kampen et al. (2005)
Model-data comparison for SHADES
Lockman Hole
SXDF
SCUBA-2
SCUBA-2 is a new generation imager for the JCMT
• Novel scanning mode to realise large-area surveys
• Imaging of the sky at 450 and 850m simultaneously
• A large (>50 arcmin2) field-of-view
• Sensitivity governed by the sky background
• Provide fully-sampled images of the sky in ~ 4 seconds
SCUBA-2 will bring “CCD-style” imaging to the JCMT for the first time
SCUBA-2 Cosmology Legacy Survey
SHADES
2 years
5 years
Survey fields
850 m survey:
field
450 m survey:
RA
area
[deg2]
XMM-LSS
2
5
ECDFS
3
Cosmos
field
RA
area
[deg2]
UDS
2
<0.25
3
ECDFS
3
<0.25
10
2
Cosmos
10
<0.25
Lockman
10
4
GOODS-N
12
0.05
Bootes
14
2
Akari-NEP
18
0.02
EGS
14
1
SA22
22
0.02
ELAIS-N1
16
2
Akari-NEP
18
1
Field selection (partly) driven by
complementary data of the
required depth; e.g., KAB=25
H1K: proposed Herschel 1000 sq. degree survey
H1K fields (white blocks) superimposed on the IRAS 100 micron maps
In the north the outlines of the other surveys are: 2dFGRS - continuous blue; VIKING/KIDS - cyan; GAMA - magenta ;
SDSS - yellow. The red circle shows the area covered by the Coma cluster.
In the south the surveys are: 2dFGRS - continuous blue; VIKING/KIDS - cyan; Dark Energy Survey - magenta;
South Pole Telescope - dashed blue.
A blank field (850 micron @ JCMT)
Add a (proto-)cluster at z=2.5
Another blank field (850 micron @ JCMT)
Add a proto-cluster at z=3.8
Galaxy evolution in and around clusters
The z=0.5
galaxy cluster
J0717.9
Subaru SuprimeCam VRz image with galaxy surface density contours
in red and the area of the ACS field outlined in green. The ACS field
traces the filamentary structure evident from the density contours
(Rich & Ebeling 2007)
Panoramic imaging in and around clusters
Subaru BVRI
imaging of A851 and
its infall region by
Kodama et al. 2001.
Red dots are at the
cluster redshift
according to their
photometric redshifts.
Exploit unique capabilities of Herschel
Figure compiled by
Mari Polletta
Herschel Open-Time Key-Programme
proposal to study the cluster infall region
 use well-defined rich cluster sample at z≈0.5
 map the infall region around these clusters out
to around 5 Mpc (depending on cluster mass)
 measure SFR and LIR for each galaxy
 measure stellar masses from near-IR (follow-up
or existing)
 remove interlopers (foreground/background)
 define environment
A survey of panoramic surveys
Target fields for the Herschel proposal
“Studying galaxy evolution where it happens”
Summary
Only far-IR and sub-mm observations allow us to
survey dusty star-formation at high redshifts and
in over-dense regions.
The future is blobby !