1. June 4, 2015Dusty2004 Spitzer Space TelescopeCen A Elliptical and (other) early-type galaxies T. Wiklind ESA/STScI

2. June 4, 2015Dusty2004 Spitzer Space TelescopeCen A 1.Cold gas in elliptical/S0 galaxies What we know today 2.What are the issues? Origin of early-type galaxies? Relation between AGN and dense gas? Connection with cooling flows Cold dust 3. Observations needed for progress Herschel ALMA

3. June 4, 2015Dusty2004 The gas content of elliptical galaxies Elliptical galaxies are gas-rich objects Type of gas Temp K Density cm -3 Mass M o Fraction Hot10 7 0.110 >0.8 Warm10 4 10 2 10 4 - 10 5 >0.5 Cool10 2 10 2 - 10 3 10 7 - 10 10 0.1 - 0.2 Dust<10 2 >10 3 10 5 - 10 7 ~0.8

4. June 4, 2015Dusty2004 Cold ISM in lenticular galaxies: Atomic hydrogen: Molecular hydrogen: Dust emission: 30-40% of far-infrared selected S0’s 25% of far-infrared selected S0’s 40-60% at 100  m (IRAS) Optical features (?) Main problem: no unbiased (or with biased controlled) survey has been done to date. Needed:survey with well-defined mass limit preferably without far-infrared bias One study has been done with a volume limited sample: S0, <20 Mpc, non-peculiar, non-Virgo Detection rate ~80% for CO emission (Welch & Sage 2003). No correlation between molecular mass and blue luminosity.

5. June 4, 2015Dusty2004 Oosterloo et al. 2002 HI in dust-lane ellipticals: Regular HI disks, extended well outside the optical boundary. Well-behaved kinematics. Long-lived features.

6. June 4, 2015Dusty2004 NGC759 CO(1-0)observed with PdB (Wiklind et al. 1997) Unresolved CO emission, implying > 10 9 M o of molecular gas gas ring with r~3” inferred and confirmed optically (B-I image) (Vlasyuk & Sil’chenko 2000)

7. June 4, 2015Dusty2004 NGC759 observed with Plateau de Bure (Wiklind et al. 1997) Unresolved CO emission, implying > 10 9 M o of molecular gas gas ring with r~3” inferred and confirmed optically (B-I image) (Vlasyuk & Sil’chenko 2000)

8. June 4, 2015Dusty2004 Gas in lenticulars (Pogge & Eskridge 1998) Molecular gas has the same distribution as the ionized gas while HI can be extended. Some lenticulars with atomic gas show no evidence of star formation (Pogge & Eskridge 1998)

9. June 4, 2015Dusty2004 Blue cores in early-types (de Mello et al. 2004) GOODS/ACS I z phot ~ 0.6

10. June 4, 2015Dusty2004 GOODS/ACS I + B + WFPC2 U Blue cores in early-types (de Mello et al. 2004) z phot ~ 0.6

11. June 4, 2015Dusty2004 The origin of elliptical galaxies Elliptical galaxies contain an old stellar population, necessarily formed at high z Two formation scenarios: (1) monolithic collapse at early times, followed by passive evolution (2) hierarchical merging, with rather late formation epoch Very luminous galaxies with extreme star formation rates are found in submm surveys at redshifts 2-3

12. June 4, 2015Dusty2004 Cimatti et al. 2004 Four elliptical galaxies at z = 1.6 - 1.9 Spectroscopically confirmed Ages ~1-1.7 Gyr (z f ~ 3) M * ~ 1-3 10 11 M o Too few such systems are predicted in hierarchical models

13. June 4, 2015Dusty2004 Chandra Deep Field South including parts of GOODS-S and UDF SIMBA observation  =1200  m rms ~0.5 mJy/beam Bergström et al. 2004

14. June 4, 2015Dusty2004 Excellent fit: Starburst galaxy at z>7, SFR ~ 500 M o /yr; M * ~ 10 12 M o Age ~ 0.5 Gyr Not so good fit: Evolved elliptical at z~3 Passive evolution, no star formation Age ~ 1-2 Gyr (z f ~ 5-7) A proto-elliptical at z>7? Submm galaxies at high redshift : High star formation rates ~10 3 M o /yr (or more) Massive systems with gas masses ~10 10 -10 11 M o (CO observations) If SFR sustained ~10 8 yrs they will form ~10 11 M o in stars For more info: Mobasher et al. 2004 Submm galaxies could be proto-ellipticals forming through either monolithic collapse or major merger events

15. June 4, 2015Dusty2004 Images from John Hibbard’s web page http://www.cv.nrao.edu/~jhibbard/ Central 7” of NGC 7252 with HST/WFPC2 Whitmore et al. 1992

16. June 4, 2015Dusty2004 About 15% of radio galaxies contain a cold ISM(molecular gas+dust). Same as FIR selected E (Lima et al 2000; Leon et al. 2002) Both centrally concentrated and extended gas distributions with masses from ~10 8 - 10 10 M o Despite large gas masses RG fall on the Fundamental Plane No clear correlation with L B. Correlation with AGN activity? Most RG’s do not have significant amounts of cold gas… Six high redshift radio galaxies have been found to contain molecular gas (z=0.2 - 3.8) (Papadopoulos et al. 2000; de Breuck et al 2003; Greve et al. 2004). HzRG may be starburst galaxies: large molecular gas mass (10 11 M o ) and high L FIR (>10 12 L o ) Radio galaxies Low redshift High redshift

17. June 4, 2015Dusty2004 NGC1275 (Per A) contains >10 9 M o of molecular gas, but unknown if connected to cooling flow or on-going merger (Lazareff et al. 1989) Molecular gas has recently been detected in 16+ cooling flow galaxies (Edge et al. 2001; Salome & Combes 2003, 2004) Molecular gas masses are 10 8 - 10 10 M o, too small to account for total cooling flow deposition Strong correlation between molecular gas and H  emission (Salome & Combes 2003) Less strong correlation between molecular gas mass and mass deposition rates (but only the central part observed) Molecular gas in cooling flow galaxies Salome & Combes 2003

18. June 4, 2015Dusty2004 Dust emission is detected in many cooling flow (e.g. Edge et al. 1999) Heating by AGN or star formation? IRAM PdB images show extended CO(1-0) and CO(2-1) emission in A1795. Apparently along the radio jet (Salome & Combes 2004). Molecular gas in cooling flow galaxies contd. Salome & Combes 2004

19. June 4, 2015Dusty2004 IRAS detected emission in ~40% of elliptical galaxies (Knapp et al. 1986) M d ~ 10 5 - 10 7 M o, T d ~ 30K ISO sample of 54 early-type galaxies (39 E’s) with detection rate ~50% (Temi et al. 2004). ISO + SCUBA gives similar result (Leeuw et al. 2004) FIR luminosity not well correlated with optical luminosities (same as IRAS results) Two dust components: (1) A warm component with T d ~ 40 K (2) A cool component with T d ~ 17-20 K Total dust mass 10x larger than inferred from IRAS data With ~constant gas-to-dust mass ratio, more cold molecular gas is implied Dust in elliptical galaxies

20. June 4, 2015Dusty2004 Leeuw et al. 2002

21. June 4, 2015Dusty2004 What can Herschel and ALMA do? ALMA Distribution and kinematics of molecular gas in ellipticals (study the structure of E potential) - Radio galaxies: is the molecular gas Necessary for activity? - Cooling flows: How is the gas related to the hot gas? Is it forming stars? Where does it form? Molecular gas in ellipticals as a function of redshift. Merger rate? (need HST/JWST for morphology) Herschel Complete and unbiased surveys of cold ISM in ellipticals / radio galaxies Detailed SEDs (+ long bolometers) to derive dust components/mass Fine-structure lines to study the physics of the cool ISM/star formation (Malhotra et al. 2000) Occurance of hot/cold dust in cooling flows distribution / heating agent