Deep Far-IR Surveys with Spitzer (and expectations for Herschel photometry) David T. Frayer (IPAC/NHSC), S-COSMOS*, FIDEL*, SWIRE, and xFLS Legacy Teams
BACKGROUND/MOTIVATION for FIR at high-z (1):LIRGs/ULIRGs numbers increase dramatically at z~1-2 Le’Floch et al. 2005: LIRGs ULIRGs Daddi et al. 2007 Caputi et al. 2007
BACKGROUND/MOTIVATION for FIR at high-z (2): Wide-Range of FIR/MIR Ratios xFLS 24um sample, Sajina et al. 2007 (see Jeyhan Kartaltepe’s talk/paper for the properties of the 70-um selected sample in COSMOS)
BACKGROUND/MOTIVATION for FIR at high-z (3): 24um+UV tend to overestimate the total L(IR) and SFRs at high luminosities need FIR [or radio measurements] for total L(IR) Papovich et al. 2007
SWIRE (49 sq-deg) Ultra-Deep 70um Counts in GOODS-N xFLS (4 sq-deg) S-COSMOS, 2.5 sq-deg) FIDEL (0.55 sq-deg) Ultra-deep 70um counts in GOODS-N (10’x10’) measured down to 1.2 mJy directly resolving about 60% of the EBL at 70um. Frayer et al. 2006
160um Counts(limited by confusion), Frayer et al. (2009) q=5 confusion level
Spitzer MIPS Extragalactic Confusion Measurements Empirical q=5 “photometric” confusion measurement, i.e., noise fluctuations below S_lim=5*sigma. Frayer et al. 2006, 2009
IR Luminosity Function FIDEL-70um, Magnelli et al. 2009 24um 2-3x fewer ULIRGs at high-z compared to conclusions from previous 24um studies
Star-Formation History (FIDEL-70um) 24um-only data inaccurate, including 70 um is better, Herschel should improve this further by measuring the total Lir directly. LIRGs ULIRGs Magnelli, et al. 2009
xFLS IR-Radio Relationship Local ratio expected at z=0.2 Frayer et al. 2006
S-COSMOS: IR to Radio, Sargent et al. 2009 Observed q70 (S70/S[20cm]): Blue=starbursts Red=“AGN”
K-corrected q70, Sargent et al. 2009 Corrections difficult at high-z due to inaccurate SED models/extrapolations need to measure the peak of the SEDs with Herschel.
Herschel is working PACS M51:
Concluding Remarks • Spitzer accounted for the evolution of the IR energy budget (to first order). • Confirmed IR-radio relationship to z~2. • Herschel will measure the cold dust and constrain the SEDs better. • Radio astronomy will be very active in the coming decade in studying the evolution of galaxies (e.g., eVLA , ALMA, and GBT observations that will measure SFRs and M(gas) and constrain the evolution and chemistry of high-z galaxies).