1. Conference summary Catherine Cesarsky ESO Moriond, March 2005

2. When UV meets infrared (and everything from gamma rays to radio) Do we see the same sources in UV and IR?

3. GALEX 24 micron MIPS IRAC GOODS

4. Summary 1. By selection, UV galaxies and IR galaxies have very different characteristic IR/UV ratios (the means differ by a factor of 10). 2. The morphological and stellar mass distributions of the two populations have good overlaps (> 70%). IR galaxies tend to be more massive and earlier types, with an excess of interacting galaxies, and UV galaxies to be less massive and later types. 3. UV galaxies are less clustered than IR galaxies. 4. Galaxies with the highest SFR (>100 M /yr, L tot > 10 12 L ), are missed in the UV samples. 5. A population of low metallicity (< 1/10 solar), low mass (<10^9 M ) dwarf UV galaxies (prototype I Zw 18) are `IR quiet’, with the IR/UV ratio ~ 0.3 or less. They occupy only a few percent of a UV selected sample. ๏ ๏ ๏

5. Moriond 2005 VC UV/mid-IR comparison of two LIRGs Charmandaris, Le Floc’h, Mirabel, ApJ, 2004, 600, L15 At z~2: UV --> R-/I- band & ISO/CAM 7μm -> Spitzer/MIPS24. The poor spatial at z~2 will result in blending of the emission from the unresolved interacting components. An increased scatter will thus be introduced in the observed optical to mid-IR colors of these galaxies, leading to a systematic underestimation of their dust content. 7μm/UV ~ 800:10:357μm/UV ~ 330:160:190 Images: HST/STIS UV - Contours: ISOCAM 7μm

6. Do we need UV to understand star formation ? YES, at least in some cases (low obscuration)

7. Rest UV Traces Star Formation Over Large Range of Specific Star Formation & SFR/Area What gives???  gas ranges 20:1   gas 1.4 ranges 70:1 Milky Way Luminous UV Galaxies Low Surface Brightness Galaxies Early Type Gals

8. Shortcut to SFH b-parameter vs. NUV-r color –Obtain b from color alone –Works when no spectra are available –Valuable for high z –Spread in x-direction due to internal extinction NUV-r  b Rest UV Traces Star Formation Over Large Range of Specific Star Formation

9. H  and UV radial profiles Thilker, Meuer, et al Radial profile differences seen in other galaxies Not all galaxies show H  deficit UV Ha

10. Star clusters as indicators/ demonstrators of star formation

11. Do we need IR to understand star formation? YES, especially for the brightest galaxies

12. Can the different star formation indicators be reconciled? Sometimes…

13. Ha/UV in SDSS Treyer, Johnson, et al. Ha/UV shows systematic trend Higher L UV, Blue NUV-r L(Ha)/L(UV)~Kennicutt Low L UV, Red NUV-r L(Ha)/L(UV) > Kennicutt

14. OII line & UV luminosities underestimate SFR values by factors 5 to 100 for starbursts & LIRGs ! SFRs as estimated by UV, [OII] & IR (Hammer et al, Venice 2003, proceedings, astro-ph/0401246)

15. SFR NUV vs. SFR dust Quite good agreement on average but... log SFR dust (M sun yr -1 ) log SFR NUV (M sun yr -1 )

16. ● At low values of A NUV, the dust emission underestimates the total SFR because of the non negligible NUV emission. ● At high values of A NUV, the NUV emission underestimates the total SFR. Problem with A NUV ? Two different trends are observed: log SFR NUV (M sun yr -1 ) log SFR NUV /SFR dust

17. Estimating extinctions and SFRs at z ~1 (Flores et al, 2004, A&A 415, 885) FORS2/ISAAC: 16 ISO galaxies, 0.4< z <1 - extinction corrected H  SFRs are close to mid-IR estimates (Elbaz et al, 2002) for SFR < 150 M O /yr (i.e. below ULIRGs)  more robust SFR estimates -luminous IR galaxies (not ULIRGs) dominates the cosmic star formation density at z~1 (confirmed by Spitzer, Le Floch et al, 2004 )  less than 20% of the star formation density is coming from extremely dust enshrouded regions

18. Deep IR surveys: do we understand what we see? Probably, but…

19. EBL: optical vs IR

20. CIRB~ 1.5 OPT IGL In local universe, about 30% bolometric light in IR; LIRGs, ULIRGs produce 2% of bolometric luminosity However,distant universe is IR. Due to LIRGs? How distant?

21. LW3 z=0 0.5 1 1.5 2 Typical galaxy spectra K-corrections LW3 15  LW2 6.7 

22. CIRB peak: 140  m Individual galaxies peak: 60 to 100  m Peak shifted to 140  m if z=0.4 to 1.3 ( ~0.85) 15  m 8  m z=0.85  z=0 140  m 80  m ISOCAM deep surveys in LW3 (12-18  m): Ideal to detect redshifted PAH for z~0.85 (or in general at z<1.5)

23. Number Counts Roughly in agreement with ISOCAM results Some confused ISOCAM sources are resolved by Spitzer The HDF-N pilot study is not an unbiased survey Marleau et al. (2004) find 24  m number counts peak at fainter flux than 15  m counts difference b/w 15 and 24  m counts is not the result of confusion of ISOCAM sources or systematic differences between the observatories

24. From the MIR ? Local universe : correlation MIR – LIR Local universe : correlation MIR – LIR (Elbaz et al, 2002) correlation radio-MIR correlation radio-MIR (Codon 1992, Yun et al, 2001) or radio is a tracer of LIR or radio is a tracer of LIR MIR + local templates or correlations => FIR=> LIR => SFR MIR + local templates or correlations => FIR=> LIR => SFR Chary & Elbaz 2001 Kennicutt 1998 Chary & Elbaz 2001 Kennicutt 1998 Dale & Helou, 2002 Lagache et et al, 2004 Lagache et et al, 2004 …….. …….. M82 (disque) (Laurent et al. 2000) 15  m vs IR IR vs IRAS 12  mIR vs ISOCAM 15  m

25. 24  m Spitzer-MIPS 15  m ISOCAM SED of a LIRG at z=0.69 (LIR~10 11.1 L ,SFR~22 M  yr-1) The PAH bump exists at z=0.7

26. ** 50 % stars born z<1.5 (70 % universe age) 36 %@ z<1 (57 %) 67 %@ z<2 (76 %) Proportion of present-day stars born in LIRGs > 50 % ==> Common phase experienced by all/most galaxies... LIRGs and cosmic star formation

27. General 24  m differential counts (this work, Chary et al. 2004, Papovich et al. 2004)

28. Model predictions S 24 /S 15 as a function of z, S 24 S > 2-3 mJy dominated by objects with S 24 /S 15  2-2.5 objects with S 24 /S 15  2-2.5 S  0.3 mJy dominated by objects with S 24 /S 15  1.5 objects with S 24 /S 15  1.5 S 2-3 -> NEW POPULATION ! -> NEW POPULATION ! S > 2-3 mJy dominated by objects with S 24 /S 15  2-2.5 objects with S 24 /S 15  2-2.5 S  0.3 mJy dominated by objects with S 24 /S 15  1.5 objects with S 24 /S 15  1.5 S 2-3 -> NEW POPULATION ! -> NEW POPULATION !

29. R-band mag versus Flux@24μm Rencontres de Moriond, March 6-12th 2005 80% completeness limit at 24μm  VERY hard to be complete in the redshift identification at any 24μm flux, using VVDS/GOODS/COMBO-17

30. IR luminosities in the CDFS 2635 sources with redshifts * Modest IR emitters at 0<z<0.5 * ULIRGs : quite rare at 0<z<1 * LIRGS: significant contribution at z>0.5 * More « normal » starbursts are not negligible neither 80% completeness limit Rencontres de Moriond, March 6-12th 2005

31. Star formation history at z<1  LIRGs/ULIRGs dominate beyond z~0.7 Chary & Elbaz 2001 Blain et al. 2002 Lagache et al. 2004... _ _ _ _ _ ULIRGs total L >10 L. 11 IR L <10 L. 11 IR Rencontres de Moriond, March 6-12th 2005 Compilation by Hopkins 2004

32. Star formation history at z<1  LIRGs/ULIRGs dominate beyond z~0.7 AGN contribution ?? * ISO/XMM : <20% (Fadda et al. 2002) * X-ray +IR bkg synthetic models : <5% (e.g., Silva et al. 2004) First Spitzer results : <15% of sources flagged as AGNs by VVDS & COMBO-17 (see also SWIRE, Franceschini et al. 2005) Rencontres de Moriond, March 6-12th 2005

33. * 55~65 % of 24μm sources at z<1 for flux>80μJy Summary * At 0<z<1, L* evolves at least by (1+z) (  exclude a pure density evolution) 3.5 * IR luminous galaxies start to dominate the SFRH at z>0.6 * LIRGs+ULIRGs = 70% of SFR at z=1 * Need a better understanding of IR SEDs : IRS GTO, MIPS SED mode... Cornell University - Ithaca, December 1st 2004

34. Is galaxy formation (the building up of galaxies) regular or episodic? Mostly episodic, even if we don’t know for sure why.

35. LIRGs: potentially double their masses in ~0.8 Gyr SFR: [OII] 3727 Open symbols From BE00: Brinchman & Ellis 2000 SFR: IR & H  Red dots: LIRGs (20-200 M O /yr) Full squares: starbursts (<20M/yr)

36. How to account for the high LIRG fraction (15% of intermediate mass galaxies) ? A specific population ? LIRGs are continuously forming stars during 3.3 Gyrs (z=1  z=0.4)  they would multiply their masses by 2 x (3.3/0.8)=8.2 !!  BUT no trace of recent formation of massive galaxies, dominated by E/S0, with 3 10 11 <M star <310 12 M O

37. Do we understand ultra luminous star forming galaxies? Yes, although debate on role of AGN not completely closed

38. Moriond 2005 VC The first 18 low-resolution IRS spectra of ULIRGs Diversity! is the name of the game…

39. Highly luminous (ULIRG) systems Highly luminous (ULIRG) systems SFR ~ 1000 M  yr -1 SFR ~ 1000 M  yr -1 Massive systems Massive systems Evidence for outflowing winds Evidence for outflowing winds Progenitors of massive elliptical galaxies? Results of submm surveys

40. Do we understand Luminous star forming galaxies? Errrrr, well…

41. Stellar properties of distant LIRGs b parameter: SFR/ = 5 +/-3 Burst duration ~ 10 8 years Burst stellar mass fraction ~ 5-10 % M/Lz ~ 0.3 (SDSS 1.6) Stellar masses: ~ 5 x10 10 M 

42. Large UVLGs = LIRGs ? UV Luminosity Density from UVLG x30 from z=0 to z=1 25% of FUV luminosity density at z=1 from UVLG SFR from LIRGs x20 from z=0 to z=1 > 70% of dust-enshrouded SFR density at z=1 from LIRGs Goldader et al. (2002) Burgarella et al. (2005)

43. Conclusions The most UV luminous galaxies in the combined GALEX/SDSS sample comprise two populations:  Large UVLGs – rare, massive disk systems  Compact UVLGs – small systems undergoing intense star formation Compact UVLGs appear similar in many respects to Lyman break galaxies  UV Luminosity, star formation rate (selected)  Size  UV extinction  Stellar mass, velocity dispersion  Metallicity Compact UVLGs may be useful analogs for LBGs

44. UV Luminous Galaxies (UVLGs) Dramatic Evolution to z=3 (DS, Ilbert, Arnouts et al) (1+z) 2.5 Luminosity density of UV luminous (LBG-analog) galaxies shows dramatic evolution: (1+z) 5 L FUV,bol > 10 10 L sol SFR > 10 M sol /yr Steeper than QSO LD evolution (Boyle+ Madau et al) UVLGs produce a significant fraction of LD at z = 1 Total

45. GALEX AIS + IRAS  Bivariate SF Luminosity Function 1000 GALEX+IRAS galaxies LBG

46. Do AGNs play a role in galaxy evolution? Yes.

47. Chandra allows to separate the X-ray emission from the nucleus and the star-forming ring

48. Jet-Induced Star Formation in Centaurus A S. G. Neff et al. New GALEX data: –Deep (~27 mag rms) –Wide field (1.2 o ) FUV emission (1500A) detected: –along jet(s) for >25 kpc (shocks) –where jet hits cold clouds (young stars) –where inner jet is disrupted (???) –possibly around radio lobes (young stars?) FUV (1500A) NUV (2300A) 5 kpc ~

49. Minkowski’s Object (cf. van Breugel) FUV + HI Neff, Schiminovich et al.

50. Results for 65 Sey2: for central (median) 174 pc (65 Sey 2); 121 pc (14-rest) Heterogeneous star formation histories. ● 10 SSP BC03 ages, Z=1 and 2.5 solar, plus a power law FC. Some, dominated by old stars (t>2.5Ga), to 80% of the optical light; Some show strong component of intermediate age stars (100Ma<t<1.4Ga); Young clusters are ubiquitous (t<25Ma), in some cases to more than 50% of the light at 4020A and in several to 20%. Strong FC component also present. This could be a genuine monster or a dusty young burst. At least 3 of the 4 components present with significant strength (more than 10%) in any one galaxy. A simple Ell galaxy + a power law (used many times before) does not apply to the bulk of Sey 2s.

51. Benson (2003) Problem can be solved with extreme super-winds >5x10 49 erg per solar mass required

52. Massive X-ray outflow in PDS 456 Reeves et al. (2003) XMM EPIC pn/MOS

53. Conclusions  Overwhelming evidence for  CDM  hierarchical structure formation  Problems with semi-analytical galaxy formation models - mechanism required to terminate SF in massive gals - plus other problems…  AGN feedback is a likely solution - may be related to the origin of the M/  relation - could also explain high-mass cut-off & cluster heating problem

54. Are galaxies sensitive to their large scale environment? Discussed yesterday.

55. Other problem: How to reconcile integrated and small scale properties?

56. V. Lebouteiller – Moriond 2005 Blue Compact Dwarfs Refs : Lebouteiller et al. (2003), Lecavelier et al. (2003), Aloisi et al. (2003), Thuan et al. (2005), Thuan et al. (2002), Lee et al. (2003)  NGC1705  NGC253  IZw18  IZw36  Markarian59  SBS0335-052 [N/H][O/H] [Si/H] [P/H] [Ar/H][Fe/H] H II region (opt. +IR em. lines) H I region (UV abs. lines) 6/18

57. Distant star formation: what came first? Consensus (purely theoretical): 1000 Mo stars