Transcript swire
The SIRTF SWIRE Survey SWIRE is a shallow/moderate depth survey of ~70 sq. degrees in all 7 SIRTF imaging bands 5 sensitivities: 3.6 m 7.3 Jy 4.5 m 9.7 Jy 5.8 m 27.5 Jy 8.0 m 32.5 Jy 24 m 0.45 mJy 70 m 2.75 mJy 160 m 17.5 mJy 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) SWIRE Simulated Image; Shupe, Fang & Xu Lockman Hole (preliminary pointing) The Power of the Mid-IR Gordon et al. As the 7.7m PAH feature redshifts into the 24m filter feature in the predicted f24m< 2mJy counts. 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: Cirrus/NH/extinction must be minimized Schlegel et al. 1998 DIRBE-calibrated IRAS 100m map B100 Contours at 1 and 2 MJy/sr Seb Oliver |b|=45 contours 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 3.6 m 4.5m 5.8 m 8.0 m 24m 70m 160m Cirrus noise, 1 # (1 Mjy/sr at 100 m) 18 nJy 40 nJy 60 nJy 300 nJy 2.0 Jy 0.1 mJy 2.0 mJy Bold: dominant noise term # model of Gautier Extragalactic* Confusion noise, 1 35 nJy 33 nJy 31 nJy 43 nJy 4.8 Jy 1.3 mJy 19 mJy SWIRE photometric sensitivity, 1 1.4 Jy 1.9 Jy 5.5 Jy 6.5 Jy 0.09 mJy 0.55 mJy 3.5 mJy * 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). Photometric Redshifts 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-in104 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 10-30 mas beam or 1 Jy rms, 2 minutes 14Gyr – galaxy evolution – 2 Gyr AGN starbursts mergers SWIRE: – 105-106 galaxies – 104-105 AGN large scale structures – hundreds of 100 Mpc-scale cells Kauffmann et al swire