The star formation history of mass-selected galaxies in the COSMOS field

Transcription

1 IR Emission, ISM and Star Formation, MPIA, Heidelberg February 22 nd 2010 The star formation history of mass-selected galaxies in the COSMOS field The IR-radio relation as a key to understanding galaxy evolution Alexander Karim, MPIA Heidelberg with Eva Schinnerer, Alejo Martinez-Sansigre, Mark Sargent, Arjen van der Wel, Hans-Walter Rix, Olivier Ilbert, Vernesa Smolcic, Chris Carilli, Maurilio Pannella, Eric Murphy [...]

2 Cosmic star formation Dunne et al. (2009) SFRD [MSun/yr/Mpc 3 ] 1 + z z Brinchmann et al. (2004)

3 Cosmic star formation SFRD [MSun/yr/Mpc 3 ] 1 + z Dunne et al. (2009) Gonzalez et al. (2009) z Brinchmann et al. (2004)

4 The 3.6um photo-z catalog by O. Ilbert & M. Salvato (2009): ~200,000 sources with photo-z / stellar masses (from best fit Bruzual & Charlot, 2003 SED) in the COSMOS field. AGN candidates removed (various criteria). Flux limit: 1uJy <=> mab(3.6um)=23.9 Log10(M* [Msol]) photometric redshift Ilbert et al., 2009 Subdivided by restframe [M(NUV)-M(r)]temp colors: Quiescent > 3.5, Star forming < 3.5

5 The 3.6um photo-z catalog by O. Ilbert & M. Salvato (2009): ~200,000 sources with photo-z / stellar masses (from best fit Bruzual & Charlot, 2003 SED) in the COSMOS field. AGN candidates removed (various criteria). Flux limit: 1uJy <=> mab(3.6um)=23.9 Log10(M* [Msol]) photometric redshift Ilbert et al., 2009 Subdivided by restframe [M(NUV)-M(r)]temp colors: Quiescent > 3.5, Star forming < 3.5

6 The 3.6um photo-z catalog by O. Ilbert & M. Salvato (2009): ~200,000 sources with photo-z / stellar masses (from best fit Bruzual & Charlot, 2003 SED) in the COSMOS field. AGN candidates removed (various criteria). Flux limit: 1uJy <=> mab(3.6um)=23.9 Log10(M* [Msol]) photometric redshift Ilbert et al., 2009 Subdivided by restframe [M(NUV)-M(r)]temp colors: Quiescent > 3.5, Star forming < 3.5

7 The 3.6um photo-z catalog by O. Ilbert & M. Salvato (2009): ~200,000 sources with photo-z / stellar masses (from best fit Bruzual & Charlot, 2003 SED) in the COSMOS field. AGN candidates removed (various criteria). Flux limit: 1uJy <=> mab(3.6um)=23.9 Log10(M* [Msol]) photometric redshift Ilbert et al., 2009 Subdivided by restframe [M(NUV)-M(r)]temp colors: Quiescent > 3.5, Star forming < 3.5

8 Image Stacking (radio continuum) Take advantage of mass-complete sample AND a dust unbiased tracer for star formation going beyond the radio sensitivity limit!

9 Image Stacking (radio continuum) Take advantage of mass-complete sample AND a dust unbiased tracer for star formation going beyond the radio sensitivity limit! Linear color gradient ujy

10 Image Stacking (radio continuum) Take advantage of mass-complete sample AND a dust unbiased tracer for star formation going beyond the radio sensitivity limit! Total 20cm flux density alpha 20cm luminosity Local calibration of IR/radio relation SFR Divide by median M * of sample Linear color gradient ujy Specific SFR

11 SSFR-M * relation over cosmic time Normal galaxies Normal galaxies Log10(SSFR [1/Gyr]) Log10(M* [MSun]) Redshift z

12 SSFR-M * relation over cosmic time Star forming galaxies Normal galaxies Log10(SSFR [1/Gyr]) Log10(M* [MSun]) Redshift z

13 SSFR-M * relation over cosmic time Log10(M* [MSun]) Log10(M* [MSun]) Log10(SSFR [1/Gyr]) Log10(SSFR [1/Gyr]) Normal galaxies Star forming galaxies 1 + z 1 + z

14 SSFR-M * relation over cosmic time SFR ~ M * 0.4 x (1+z) 4.2 SFR ~ M * 0.7 x (1+z) 3.5 Log10(M* [MSun]) Log10(M* [MSun]) Log10(SSFR [1/Gyr]) Log10(SSFR [1/Gyr]) Normal galaxies Star forming galaxies 1 + z 1 + z

15 IR/radio relation (SF galaxies) Does it hold at high z also for,normal galaxies? Stacking of all samples also at 24 and 70um q24[70]=log10(ftot(24[70]um)/ftot(20cm)) ~10x deeper analysis compared to Sargent et al. (2010)

16 IR/radio relation (SF galaxies) Does it hold at high z also for,normal galaxies? Stacking of all samples also at 24 and 70um q24[70]=log10(ftot(24[70]um)/ftot(20cm)) ~10x deeper analysis compared to Sargent et al. (2010) q24 (observed) q70 (observed) Redshift High LTIR results (Sargent et al. 2010) still valid for lower mass systems IT WORKS!!! Redshift

17 Total 24/70um flux density SFRs: Radio vs IR emission IR template SED TIR (8-1000um) luminosity from 24um or 24+70um SFR

18 Log(LTIR [LSun]) from 24um (Chary & Elbaz, 2001) SFRs: Radio vs IR emission Log(LTIR [LSun]) from 24um+70um (Chary & Elbaz, 2001)

19 Log(LTIR [LSun]) from 24um (Chary & Elbaz, 2001) Log(LTIR [LSun]) from 24um (M82) SFRs: Radio vs IR emission Log(LTIR [LSun]) from 24um+70um (Chary & Elbaz, 2001)

20 Log(LTIR [LSun]) from 24um (Chary & Elbaz, 2001) SFR(20cm) [MSun/yr] SFRs: Radio vs IR emission Bell (2003) Log(LTIR [LSun]) from 24um+70um (Chary & Elbaz, 2001) SFR(TIR) [MSun/yr] from 24um+70um

21 Log(LTIR [LSun]) from 24um (Chary & Elbaz, 2001) SFR(20cm) [MSun/yr] SFRs: Radio vs IR emission Damen et al. (2009) Bell (2003) Log(LTIR [LSun]) from 24um+70um (Chary & Elbaz, 2001) SFR(TIR) [MSun/yr] from 24um+70um LTIR(24um) slightly too high at high LTIR(24+70um) Excellent agreement of 20cm & 24+70um TIR SFRs at all z and M*!

22 Log(LTIR [LSun]) from 24um (Chary & Elbaz, 2001) SFR(20cm) [MSun/yr] SFRs: Radio vs IR emission Damen et al. (2009) Bell (2003) Log(LTIR [LSun]) from 24um+70um (Chary & Elbaz, 2001) SFR(TIR) [MSun/yr] from 24um+70um LTIR(24um) slightly too high at high LTIR(24+70um) Excellent agreement of 20cm & 24+70um TIR SFRs at all z and M*!

23 Summary & Conclusion Results (SFH of normal galaxies) Rich and mass-complete sample + stacked radio continuum emission (dust unbiased SFR tracer, not severely confusion noise limited) Co-evolving (S)SFRs of normal (SF) galaxies at all probed masses; no evidence for change of SFR-M* relation with cosmic time and no clear sign for a turnover of evolutionary behavior at z > 2 Results (IR/radio relation) No hints for evolution of IR/radio relation for SF galaxies at z < 3 based on stacking at 24 and 70um Perfect agreement of radio continuum and TIR(24+70um) derived SFRs at all probed masses and redshifts