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Part 3 The History of Stellar Formation in the Universe

Part 3 The History of Stellar Formation in the Universe. 1) Multi-wavelength views of the past active star formation phases. 2) Galaxy build up with cosmic time. 3) General constraints from the cosmological fossil remnants of the past activity (stars, metals, background radiations)

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Part 3 The History of Stellar Formation in the Universe

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  1. Part 3The History of Stellar Formation in the Universe • 1) Multi-wavelength views of the past active star formation phases. • 2) Galaxy build up with cosmic time. • 3) General constraints from the cosmological fossil remnants of the past activity (stars, metals, background radiations) • 4) Future Perspectives

  2. Log Ψ(m) 1) Constraining the high-M part of stellar initial mass function through direct SFR determination

  3. Looking at the past ... Hα based local SFR in (normal) Sp/Ir galaxies Comoving Star Formation Rate & Metal Production Rate Densities as a function of redshift (comic time), as inferred from UV-continuum observations (Madau et al.)

  4. Sferoidal Galaxies Disk Galaxies The past of the universe made available to direct inspection for the fist time. The evolutionary history of S.F. first determined.

  5. LW3 12-18m filter z=0 0.5 1 1.5 2 Typical source spectra THE INFRARED SPACE OBSERVATORY (1996-98) First access to the high-z universe in wavebands from 10 to 200 μm … exploratory mission … K-corrections

  6. HDF-North image overlayed by the ISOCAM LW3 15  contours by Aussel et al. 1999 2 arcmin

  7. COMPARISON OF SENSITIVITIES 80 Elbaz and Cesarsky (2003)

  8. The ISO deep 12 – 18 µm LW3 Lockman survey 22’x22’ field total time: 43 ksec redundance factor ~7 283 sources detected between 0.1 and 8. mJy (5sigma) 9% of sources are stars 85% of optical identifications in r’ (r’<24.5) Credits to: G. Rodighiero, C. Lari, D. Fadda, D. Elbaz, H. Aussel, C. Cesarsky, S. Berta

  9. The LOCKMAN HOLE as seen by PHOT at 95 μm (Rodighiero et al. 2003) 44 arcmin THE SURVEY area : ~40´ x 40´ number of sources detected:36(above 4 sigma). 10 sources present both CAM and RADIO counterparts. minimum flux level: ~30 mJy N E

  10. Optical identifications of LW3 deep sources: The main contributors to the Cosmic Infrared Background (mean redshift z~0.7) Interacting sources Single sources

  11. JCMT 15m The SCUBA 37 element bolometer array at =850 

  12. Spectral Energy Distributions of Sub-mm selected sources

  13. Effects of K-correction in the millimeter (Blain et al. 2002)

  14. Optical: Palomar 200 UBI SCUBA smoothed to 20” resolution (Note: the brightest SCUBA source has no visible counterpart) SCUBA sources in the field of the cluster A1835

  15. Timescales for the formation of stars in IR-selected starbursts (A.F. et al. 2003) Most of these luminous galaxies shoud have experienced several episods of SF tSF  M*/SFR

  16. Quiescent phase of SF during most of the Hubble time, slowly building stars from the regular flow of gas in rotational supported galaxy disks Thin-disk geometry => moderate dust extinction, originates the optical BKG Transient starbursting phases, recurrently triggered by galaxy mergers and interactions Violent relaxation, generation of galaxy spheroids Large-scale redistribution of the dusty ISM into the inner galactic regions => high extinction => origin of CIRB A 2-phase SF: origing of galactic disks and spheroids Quiescent star-formation Active bursts of SF

  17. IR-starbursts UV-optical galaxies Optical & X-ray AGNs Evolution of the comoving luminosity density (A.F. et al. 2001)

  18. The Space Infrared Telescope Facility (SIRTF) • Innovative payload design & mission orbit • Earth-trailing heliocentric orbit, simply drifting behind Earth as it circles the Sun. • SIRTF will drift away from Earth at the rate of ~ 0.1 AU/year. The drifting heliocentric orbit places SIRTF in "deep space," where the ambient temperatures are about 30 to 40 K. • SIRTF can carry much less liquid helium cryogen than it would need in an Earth orbit. • Large instantaneous view of the celestial sky

  19. Spitzer vs. ISO Fluxes @ 15-16 m Legenda: HDF-N, HDF-S, and the Marano surveys (Elbaz et al. 1999, and the references therein); the gravitational lensing cluster survey (Altieri et al. 1999); ELAIS-S1 (Gruppioni et al. 2002); and the Lockman and Lockman Shallow surveys (Rodighiero et al. 2004). Good new: calibration & basic results: OK

  20. SUMMARY OF FAR-IR EXPLORATIONS • Star-formation activity in galaxies over very wide fraction of Hubble time • Fast increase of comoving SFR from local to z ~ 1 • From z ~ 1 to z ~ 3-4 it does not increase any more, wide plateau (likely to very high-z) • Concomitant Starburst and AGN activity [AGN/SB global fraction ~ 10-20%, still with large uncertainty => the AGN/SB duty cycle ~ 10-20%] • Cosmic evolution of emissivity remarkably dependent on the luminosity class

  21. 24 m Spitzer map of 775 arcmin2 of overlap between MIPS and COMBO-17 (Le Floch et al. 2005)

  22. Total infrared luminosities of the MIPS 24 µm sources identified with a redshift at 0<z <1.2 (+ symbols), derived using luminosity-dependent SED templates. Photo-z from COMBO-17. IR luminosities translated to “IR-equivalent SFR” assuming the calibration from Kennicutt (1998). Thick solid line: luminosity limit for 24 µm flux of 0.08mJy (80% survey completeness).

  23. The evolutionary 15 mu luminosity function (LeFloch et al.)

  24. Measuring the bolometric fluxes Correlations of the MIR and => MIR flux as a measure of the Star Formation Rate

  25. UV-optical selected The Spitzer-recovered SFR history at z=0 to 1 (LeFloch et al.)

  26. MIPS 24 m filter z= 0 ISO 15 m 0.5 1 Typical source spectra Spitzer (MIPS) 24µm : much better response to high-redshift dust emission than ISO

  27. Perez-Gonzales et al. (2005) For a total of ~8000 sources at 24 m Examples of the photometric redshift estimations

  28. L=L0(1+z)nL = 0 (1+z)nD

  29. History of stellar formation from far-IR observations

  30. Clear indications by Spitzer far-IR surveys of strong luminosity dependence of the cosmological evolution SCUBA galaxies

  31. Log Ψ(m) 2) Constraining the low-M part of stellar initial mass function through indirect SFR determination

  32. - 100% - 10% log ρ(>z) - 1% The cumulative stellar mass density vs. Star Formation Rate

  33. z=1.27 1Gyr 3 Gyr 5 Gyr 7Gyr t=9Gyr Photometric estimates of the stellar mass in high-z galaxies

  34. Simulations of Spitzer/IRAC observations to constrain the stellar mass in high-z galaxies G. Rodighiero, S. Berta, P. Cassata, S. Berta, M. Vaccari, M. Nonino, E. Vanzella, E. Hatziminaoglou, J. Antichi, S. Cristiani, A.F.

  35. 5302 IRAC sources with S3.6µm > 1 µJy inside the Spitzer/ACS common area of 160 sq. arcmin., all morphologically selected. Reference sample includes 1478 IRAC sources with S3.6µm > 10 µJy (75% have a K-band counterpart). 47% spectroscopic redshifts (+ photo-z)

  36. Luminosity & stellar mass functions (A.F. et al. 2005)

  37. M > 1010Mo Integral quantity Differential quantity Integrated comoving stellar mass density as a function of redshift, split by morphology, with a mass cutoff at Mo > 1010Mo. The solid horizontal line marks the local stellar mass density as measured by Cole et al. (2001) over the same mass range.

  38. Late-type galaxies Early-type galaxies Evolutionary mass functions by morphological type

  39. Discovery of the Cosmic Infrared Background (CIRB) (Hauser et al. 1998; Puget et al. 1996) λ=100 μm

  40. COBE HST (opt)=17 nW/msr (IR)=40 nW/msr Relating the cosmic fossil remnants with the history of cosmological star formation • The CIRB + Optical Backgrounds vs. the local stellar mass density

  41. Can explain the CIRB+COB without conflicts with local stellar and metal density with reasonable IMFs =>

  42. SUMMARY • Evolutionary patterns for both galaxies and AGNs fairly well established, thanks to extensive multi- approach. • Star-formation activity in galaxies over very wide fraction of Hubble time: • fast increase of comoving SFR from local to z ~ 1 • from z ~ 1 to z ~ 3-4 it does not increase any more, wide plateau (likely to very high-z). • Concomitant Starburst and AGN activity [AGN/SB global fraction ~ 10-20%], evident in SCUBA sources. • Cosmic evolution of emissivity remarkably dependent on the luminosity class for galaxies & AGNs. • Galaxy evolution depends on (stellar & total) mass, higher M & L objects evolving on a faster cosmic track. • First (yet qualitative) evidence that evolutionary SFR and the progress of stellar mass build up in galaxies, provide entirely consistent views. • However, there we still miss a critical ingredient, the I.M.F.

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