Published on August 29, 2007
Submm properties of high-redshift galaxies: Submm properties of high-redshift galaxies IDA submm workshop Copenhagen Dec 20-21, 2004 Kirsten Kraiberg Knudsen Max-Planck-Institute für Astronomie Why are submm observations important for cosmology?: Why are submm observations important for cosmology? About half the activity at z andgt; 1 is obscured by dust Extragalactic background radiation: (Steidel et al., 1999) Cosmic star formation history: Slide3: Dust + CO detection z=6.42 (1148+52) 3’ MAMBO VLA CO 3-2 46.6149 GHz Off channels rms = 60 µJy Prodigious dust and molecular gas formation within 0.9 Gyr of big bang (Walter et al., 2003; Bertoldi et al., 2003) Dust + CO detection z=6.42 ( 1148+52) S_250 = 5.0 mJy =andgt; L_FIR = 1.2e13 L_sun, M_dust=7e8 M_sun S Dv = 0.2 Jy km/s =andgt; M(H_2) = 2e10 M_sun 5 mJy 0.2 Jy km/s Submillimetre Cosmology: Submillimetre Cosmology Sources do not fade much from z = 1 to 8 Galaxies up to z ~ 10 detectable Submm samples have high proportion of high-z galaxies Luminosities without precise redshifts Deeper surveys probe fainter galaxies, not higher z Large negative k-correction: From bright to faint submm galaxies: From bright to faint submm galaxies Rob’s talk: bright sources with f850 andgt; 5 mJy Limitation: The blank field confusion limit for the JCMT 850m: ~ 2 mJy To probe fainter with the current instrumentation use: gravitational lensing Submm/mm cosmology pre-2005: Submm/mm cosmology pre-2005 ~10 surveys with SCUBA and a few with MAMBO (blank field surveys and lensing surveys) Number counts: successful for andgt; 0.1 mJy Clustering of SMGs – challenged by limited survey areas Understanding the nature of the submm population identification of submm galaxies getting redshifts getting spectral line data (stay tuned for Thomas’ talk) comparison with results on z andlt; 0.2 galaxies Understanding their role in galaxy formation+evolution link between SMGs and other high-z galaxy populations development of numerical codes for galaxy formation Submm detections of other high-z galaxy populations Number counts: Number counts The Leiden-SCUBA Lens Survey: 12 clusters + 1 blank field (71 arcmin2) Turn-over between bright and faint. Dominant contribution to EBL is f850 ~ 0.5 –2.5 mJy NUMBER COUNTS FROM THIS SURVEY WILL APPEAR IN A PUBLICATION SOON. - kirsten. Number counts – fainter and at more ’s: Number counts – fainter and at more ’s For immediate progress: other ’s 350m with SHARC-II (CSO) and new bolometer array at APEX 450m with SCUBA-2 (JCMT) Longer term progress: fainter sources (f850 andlt; 1 mJy) ALMA (high resolution and sensitivity needed!) (complication: small field-of-view) more FIR wavelengths: Herschel Clustering: Clustering Measuring the clustering of SMGs: Where do SMGs form? Comparison with other high-z galaxy populations Attempts with current data: 8 mJy-survey (Scott et al., 2003) Canada-UK Deep SCUBA Survey (Webb et al., 2003) MAMBO survey of 8 mJy survey (Greve et al., 2004) SMGs come in pairs upper limits on correlation length Nature of SMGs: Nature of SMGs What triggers/drives the prodigious star formation rates observed in submillimetre-selected galaxies? The role of SMGs? Do they represent a short-lived phase of the evolution of e.g. massive galaxies? Are the there differences between the bright and faint SMGs? Slide11: Kneib, van der Werf, Knudsen et al., 2004 (A2218) Faint SMGs (1) – SMMJ16359+6612 Faint SMGs (2): Faint SMGs (2) Arc in cluster MS0451-0305 (Borys et al., 2004) f850 ~ 0.4 mJy redshift z ~ 2.9 LBG and ERO pair Source plane seperation of 10 kpc - possibly interacting system Faint SMGs (3) – SMM J10570-03361: Faint SMGs (3) – SMM J10570-03361 (Knudsen, 2004; van Dokkum et al., 2004) z = 2.423 stellar mass ~ 3x1011 M H Distant red galaxy J-Kandgt;2.3 Slide14: D Deep multi-wavelength data is absolutely necessary! Submm observations of other high-z galaxy populations (1): Submm observations of other high-z galaxy populations (1) Lyman Break Galaxies (LBGs) Selects galaxies with redshift z andgt; 3 (e.g. Steidel et al., 1999) Two LBGs detected individually (Westphal-MMD11 and cB58) No significant detection in stacking analysis; expected contribution to submm EBL 2-5% (andlt;20% for 1andlt;zandlt;5) (Chapman et al., 2000; Webb et al., 2003) Extremely Red Objects (EROs) – (I-Kandgt;4 or R-Kandgt;5.3) Selects galaxies with redshift z andgt; 1 (e.g. Cimatti et al., 1999) Average flux: andlt;f850andgt; ~ 0.8 mJy ; contribution to submm EBL ~ 30% (Knudsen 2004; Webb et al., 2004; Wehner et al., 2002) Submm observations of other high-z galaxy populations (2): Submm observations of other high-z galaxy populations (2) Distant Red Galaxies (DRGs) – J-K andgt; 2.3 Selects galaxies with redshift z andgt; 2 (van Dokkum et al. 2004 and Förster Schreiber et al., 2004) Source density similar to that of SMGs (~ 3-4 arcmin-2) Average flux : andlt;f850andgt; ~ 1.2 mJy ; contribution to submm EBL ~ 20-25% (Knudsen, 2004) Submm detection of individual high-z galaxies will in most cases require more sensitive and higher resolution instruments such as ALMA. Submm selected QSO: SMM J04135+10277: Submm selected QSO: SMM J04135+10277 Knudsen, van der Werf andamp; Jaffe, 2003 Summary: Summary The JCMT 850µm confusion limit can be pushed using gravitational lensing. The dominant contribution to EBL from SMG population comes from f850 ~ 0.5-2.5 mJy. Faint SMGs typically have Lya absorption. Detection and identification of faint SMGs will benefit tremendously from future telescope and instrumentation facilities such as ALMA. Statistical detection of EROs and DRGs with average flux ~ 1 mJy and contribution to EBL of ~ 20-30%.