the sirtf swire survey swire is a shallow/moderate depth survey of ~70 sq. degrees in all 7 sirtf...
Post on 19-Dec-2015
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The SIRTF SWIRE Survey SWIRE is a shallow/moderate depth survey of ~70 sq. degrees in all 7 SIRTF imaging bands
5 sensitivities:
17.5 mJy160 m
2.75 mJy70 m
0.45 mJy24 m
32.5 Jy8.0 m
27.5 Jy5.8 m
9.7 Jy4.5 m
7.3 Jy3.6 m SIRTF is ideally designed for detailed study of the history of star formation
MIPS is optimized for star-forming galaxies and AGN
IRAC is optimized for old and/or reddened stellar populations
SWIRE Science Goals
To enable fundamental studies of cosmology and galaxy evolution in the Mid- and Far-IR for 0.5<z<2.5:
• Evolution of star-forming and passively evolving galaxies with time in the context of structure formation models
• Spatial distribution and clustering of evolved galaxies, starbursts and AGN, and the evolution of their clustering
• Evolutionary relationship between galaxies and AGN, and the contribution of AGN accretion energy to the cosmic backgrounds
SWIRE Survey Design
• The 1<z<2.5 universe is less well studied than the z>3 universe
• Galaxy evolution must be studied in the context of environment
SWIRE will sample:
– Several hundred >100 Mpc co-moving volumes
– Redshift range 0.5<z<2.5
– 7 target fields to combat cosmic variance
The SIRTF SWIRE Survey
Plotting only every 10th galaxy
SFRs for galaxies; compared to integrated SFH (which is normalized by volume)
The Power of the Mid-IR
As the 7.7m PAH feature redshifts into the 24m filter
feature in the predicted f24m< 2mJy counts.
Gordon et al.
IRAC Observation Plan
For a 10 sq deg area, need 24 AORs for two coverages
• Each AOR: 1.75º x 30
6 columns by 21 rows, grid spacing 300
two cycling dithers at each map grid point
• Total coverage: 4x30 sec per point
MIPS Observation Plan
• Optimization at 24 and 70m due to confusion limit at 160m.
• Medium scan rate: 4 second exposures
– 10x redundancy at 24 and 70 microns
– filled 160 m map
• Two epochs
– redundancy
– asteroid/transient removal; destriping
The Importance of Field Selection:
Schlegel et al. 1998 DIRBE-calibrated IRAS 100m map
B100 Contours at 1 and 2 MJy/sr
||=45 contours
Cirrus/NH/extinction must be minimized
Seb Oliver
SWIRE Field Selection
FIELD RA
J2000
Dec ISSA
MJy/sr
E(B-V) Size
Sq. deg
ELAIS-S1 00h38m30s -44d00m00s <0.4 0.008 15
XMM-LSS 02h21m00s 05d00m00s 1.1 0.027 10
Chandra-S 03h32m00s -28d16m00s <0.4 0.001 5
Lockman Hole 10h45m00s +58d00m00s <0.4 0.006 15
Lonsdale Hole 14h38m00s +59d15m00s <0.4 0.012 10
ELAIS-N1 16h13m30s +55d16m00s <0.4 0.007 10
ELAIS-N2 16h36m48s +41d01m45s <0.4 0.007 5
Sensitivity, Cirrus and Confusion Noise
Table A-2: Expected SWIRE Performance: Noise and Sensitivity Wavelength Cirrus noise, 1 #
(1 Mjy/sr at 100 m) Extragalactic* Confusion noise, 1
SWIRE photometric sensitivity, 1
3.6 m 18 nJy 35 nJy 1.4 Jy 4.5m 40 nJy 33 nJy 1.9 Jy 5.8 m 60 nJy 31 nJy 5.5 Jy 8.0 m 300 nJy 43 nJy 6.5 Jy 24m 2.0 Jy 4.8 Jy 0.09 mJy 70m 0.1 mJy 1.3 mJy 0.55 mJy 160m 2.0 mJy 19 mJy 3.5 mJy
Bold: dominant noise term # model of Gautier * derived from Xu et al. model confusion distribution
Supporting Observations
Optical, NIR: NOAO, ESO, Palomar, INT, 2dF, Keck
Three Tiers:
r' 25 70 sq deg
g'r'i'Ks 26 / 25 / 24 / 19.5 12+
g'r'i' 27 / 26 / 25 3+
Supporting Observations
Radio: Median predicted flux is 43Jy
Too deep for large area coverage
Selected very deep VLA in small areas:
• 3 @ 3Jy rms
• 3@ 7.5Jy rms
X-ray: Selection wrt existing/planned deep Xray surveys:
Lockman Hole
Chandra-S
ELAIS
XMM-LSS
Anticipated Early SWIRE Results
BRK magnitude distributions
observations: Cohen et al. 2000, Hogg et al. 2000
ISO 15m sample of Aussel et al. (1999).
Examples of Additional Science made possible
• Hundreds of field brown dwarfs, especially T (“methane”) dwarfs
• 50-60 circumstellar debris disks (to 100 pc), and HR4796A analogs to 1kpc
•Thermal emission at 8 and 24m from main belt asteroids as small as 1km
• Serendipitous discoveries; rare objects to 1-in-104 to 1-in-106
Identifying SIRTF Sources
Confusion and cirrus noise dominate FIR/submm observations
Good complement comes from deep radio surveys to locate the UV-O-NIR counterparts
– median SWIRE 20cm depth is ~ 75 Jy
– impossible for VLA over large areas
– the Square Kilometer Array can map:
1 sq deg
10 nJy rms, 24 hours or 1 Jy rms, 2 minutes
10-30 mas beam