Luminous Infrared Galaxies

Transcription

1 Luminous Infrared Galaxies FIRSED April 3, 2013

2 The Great Observatories All-sky LIRG Survey (GOALS) IRAS-detected galaxies with f 60μm > 5.24 Jy & b > 5 o 201 galaxies with L IR L HST, Chandra ~ 88 LIRGs; Spitzer, Galex, Herschel ~ 201 LIRGs FIRSED April 3, 2013

3 Luminous & Ultraluminous Infrared Galaxies LIRGs: L IR [ μm] L ; ULIRGs: LIR L Spiral galaxies which show an increasing tendency to be involved in interactions or mergers with increasing luminosity Rich in optically-visible star clusters NGC 5257/8

4 Luminous & Ultraluminous Infrared CO(1 0) Galaxies Contours = HI CO(1 0) Spiral galaxies which show an increasing tendency to be involved in interactions or mergers with increasing luminosity Rich in optically-visible star clusters Rich in dust, and both neutral and star-forming molecular gas

5 Luminous & Ultraluminous Infrared Galaxies Contours = HI AGN Mrk 231 Spiral galaxies which show an increasing tendency to be involved in interactions or mergers with increasing luminosity Rich in optically-visible star clusters Rich in dust, and both neutral and star-forming molecular gas Evidence of Active Galactic Nuclei (AGN) activity

6 U/LIRGs and luminosity function log Φ (Mpc 3 M bol 1 ) IRAS BGS IRAS 1Jy ULIGs Mrk Seyferts Mrk Starburst cds PG QSOs Normal galaxies log L bol (L ). The local space density of LIRG is low and overtakes that of normal galaxies beyond a Lbol ~ L

7 U/LIRGs and the Main Sequence Starbursts Main Sequence LIR > L + LIR L The high end luminosity of the LIRG population lie above the main sequence with SFR ~ 100s if the IR is tracing only star formation

8 Ultraluminous IR Galaxies & the evolution of QSOs? Gas-rich Disk Progenitors with seed SMBH (Sanders et al. 1988)

9 Ultraluminous IR Galaxies & the evolution of QSOs? Enhanced Star Formation; SMBH building (Sanders et al. 1988)

10 Ultraluminous IR Galaxies & the evolution of QSOs? Optically luminous QSO phase (Sanders et al. 1988)

11 Evolutionary byproduct Elliptical/SO Galaxy (e.g., Barnes & Hernquist 1992)

12 Gas-rich Progenitors Starburst/AGN; Dust-enshrouded phase; cool IR colors Dust-clearing; AGN-dominant phase; warm IR colors Elliptical Byproduct

13 SED evolution: Cool Warm (f25μm/f60μm < 0.20) (f25μm/f60μm 0.20) Dust-enshrouded phase Dust-clearing phase

14 The importance of IR for LIRG studies νirlir / νoptlopt as Lbol (Sanders & Mirabel 1996): see Vivian U s talk for an update

15 The importance of IR for LIRG studies The SFR(UV) vs. SFR(IR) discrepancy grows with increasing LIR (Howell et al. 2010)

16 An imaging census of light from a LIRG HST Far-UV Unobscured massive star formation 5 kpc (Inami et al. 2010)

17 HST Optical Unobscured star formation 5 kpc (Inami et al. 2010)

18 HST Optical Unobscured star formation 5 kpc (Kim et al. 2013)

19 1.6μm HST NIR embedded NRG sources + old stellar population 5 kpc (Inami et al. 2010)

20 Spitzer mid-ir Embedded Star Formation & AGN Dust emission 5 kpc (Inami et al. 2010)

21 Spitzer mid-ir Embedded Star Formation & AGN Dust emission 0.4 IIZw096 source D - IRS SL only [NeII] Flux density (Jy) PAH [SIV] Rest wavelength (microns) 5 kpc (Inami et al. 2010)

22 Chandra X-ray Embedded Star Formation & AGN F E 1 10 CGCG Energy (kev) 5 kpc (Inami et al. 2010)

23 JVLA Embedded Star Formation & AGN 5 kpc (Barcos et al. 2013)

24 1.6μm Cycle 0 CO(6 5) Stay Tuned ALMA Dust continuum distribution star-forming molecular gas tracers (Stierwalt et al. 2013)

25 Isolated System?

26 Mid-Stage - progenitors intact NGC 5257/8

27 Mid-Stage - overlapping disks, double AGN + outflow (Mazzarella et al. 2012)

28 Late Stage - single nucleus, weak AGN NGC 2623 (Evans et al. 2008)

29 The utility of IR/submm/radio emission assessment of the ionization mechanisms/source(s) in obscured regions and the optical depth towards these regions assessment of the physical state in molecular clouds measurement of the physical sizes of active regions and thus the IR surface brightness measurement of the kinematics of the gas, and thus a assessment of rotation (e.g. for dynamical mass estimated) and importance of infall/outflow in obscured regions...at wavelengths that are energetically important

30 SED as a function of telescope λ coverage JWST ALMA Spitzer JVLA Herschel Mrk 231 Arp 220 JWST, ALMA and JVLA provide sub- resolution

31 The utility of IR/submm/radio emission 1. Spitzer: AGN/Starburst diagnostics (see Veilleux s talk) 2. Herschel: the [C II]/FIR decrement 3. Herschel: CO SLED 4. ALMA: CO(6 5) emission

32 (1) AGN-Starburst diagnostics: ISO data high/low ionization destruction by AGN (Genzel et al. 1998)

33 AGN-Starburst diagnostics ISO (Genzel et al. 1998)

34 AGN-Starburst diagnostics ISO Spitzer (Genzel et al. 1998; Armus et al. 2007)

35 AGN-Starburst diagnostics PAH Spitzer absorption by ionizing source E.g., Strength of PAH anti-correlated with AGN strength (Armus et al. 2007)

36 AGN-Starburst diagnostics low-ionization [Ne II] high-ionization [Ne V] E.g., [Ne V] / [Ne II] correlated with AGN strength (Armus et al. 2007)

37 Spitzer IRS: AGN vs. starburst diagnostics Mid-IR diagnostics used: [NeV]/[NeII], [OIV]/[NeII], 6.2 μm PAH EQW & MIR continuum ratios (e.g., Veilleux et al. 2009) Punchline 1: Based on the MIR: 10% of local LIRGs have dominant AGN Punchline 2: AGN are responsible for 12% of LIR of LIRGs in the local Universe Is the mid-ir a sufficiently long wavelength to diagnose AGN/ starburst fractions? (Petric et al. 2011; see Veilleux s talk for more in-depth discussion)

38 (2) The [C II] 158μm/FIR decrement in U\LIRGs L[C II] is ~ 1% of LFIR in normal, star-forming galaxies Major coolant in the neutral ISM ionization potential = ev (e.g., Luhman et al. 2003)

39 [C II]/FIR vs. the star formation efficiency 10 1 [C II] 158µm 10 2 FIR [CII]/FIR Line flux / FIR LFIR/M(H2) = star formation efficiency [CII]/FIR as the star formation efficiency Similar decrements are seem HII galaxy for other forbidden submm lines LINER Seyfert & QSO Blue Compact Dwarf (Gracia-Carpio et al. 2011)

40 low [C II]/FIR galaxies have high ionization parameters (U) high ionization / low ionization warmer dust Figure 3. Ratio of [N ii] 205µm to IR luminosity is plotted against((a)and(d))ir luminosity,(b)iras 60µm/100µm color,and(c)[oiii] 88µm/[Nii] 205µm flux ratio. The symbols are the same as in Figure 2 except that here larger circles represent ULIRGs. The symbols enclosed by an additional red circle in panels (a) and (b) are the same sources as shown in panels (c) and (d). Equation (1) is shown by the dashed line in panel (a). The ordinate of panel (d) is a nominal value after the correction for the hardness effect (using the equation shown in this panel). Mrk 231 is outside the plotted range of panel (d). (A color version of this figure is available in the online journal.)... as inferred from the [OIII] / [NII]...and dust temperature only 5 evhigherthanthatneededfortheformationofn ++, and thus the [O iii]/[n ii] lineratiosareevenstrongerindicator of the hardness. Furthermore, this ratio is insensitive to the gas density (Rubin 1984). Except for M82 (Duffy et al. 1987) and Mrk 231 (Fischer et al. 2010), all of the [O iii] 88 µmfluxesare was calculated according to the fitted L (Zhao et al. 2013; Diaz-Santos et al. 2013; see also Abel et al. 2009; Gracia-Carpio [O iii] /L [N ii] L [N ii] /L 2011) IR adopted from Brauher et al. (2008). the real scatter in the L [N ii] L IR relation might probably be even smaller for these galaxies. To obtain a direct view of how much the scatter can be reduced, we also display the hardness-corrected L [N ii] /L IR,which relation, for the [O iii]sample in Figure 3(d) (arbitrarily scaled). Comparing to Figure 3(a), one can see that the scatter is reduced

41 low [C II]/FIR galaxies are optically thick 1140 BRANDL ET AL. =ln(fobs/fcont)9.7μm [CII]/FIR as optical depth Fig. 10. IRS spectra of Mrk 52, NGC 7714, NGC 1222, NGC 7252, NGC (Diaz-Santos 2146, et NGCal. 520, 2013; NGC 3628, and spectra NGC 4945 arranged - Brandl to illustratet the gradual al. 2006) effect of increasing silicate absorption from top to bottom. The flux densities F k have been arbitrarily scaled for better comparison. increasing optical depth Fig. Fig. 6 to and to th extinctio malized starbur emissi to NG depres cate ab found Am (botto far the et al. 2 depth i depend strong

42 low [C II]/FIR galaxies have compact IRemitting regions Fit to SB-dominated U/LIRGs low PAH EQW - AGN-dominant U/LIRGs [CII]/FIR as the compactness of the MIR emission (Diaz-Santos et al. 2013)

43 [CII] PAH HII Region H+ H+ H+ H+ H+ H+ H+ H+ H+ H+ UV H o PAH e- PAH H+ H+ >>[CII]<< H o H o H o >>[CII]<< PAH [CII] H o FIR H+ H+ Molecular Cloud [CII] PAH [CII] Ho H o PDR As U, the gas opacity in the HII regions chance of UV photons dust FIR photons high, especially if the starburst region is optically thick

44 U/LIRGs with high SSFRs Main Sequence Starbursts = SFR/M*... form their stars in warm, compact, optically thick regions (Diaz-Santos et al. 2013)

45 U\LIRGs with high SSFRs radio calibrated sizes... form their stars in warm, compact, optically thick regions (Elbaz et al. 2011)

46 TIES OF COMPACT STARBURSTS 5 U\LIRGs with high SSFRs 1140 BRANDL ET AL. Figure 5. The specific star formation rate of each galaxy plotted as a function of radio spectral index (generally) measured between 1.49 and 8.44 GHz (see Table 1). Sources having 8.44 GHz brightness temperatures larger than K, indicating the presence of an AGN, are identified by filled circles. We additional identify those sources categorized as being AGN dominated by their low 6.2 µm PAHEQW(circleswithcrosses);note,eachof the sources with an 8.44 GHz brightness temperature larger than Kalsohasa6.2µm PAHEQW< 0.27 µm. Thesolidline is a fit to the non-agn sources, as identified by either their high 8.44 GHz brightness temperature or low 6.2 µm PAH EQW,ofthe form ssfr = η(1 e α α MS )+ssfr MS e α α MS (see 4.2), which is forced to fit through the typical radio spectral index (α MS 0.8) and specific star formation rate (ssfr MS 0.25 Gyr 1 )ofz 0 star-forming galaxies (diamond). The corresponding error bars indicate the 1σ dispersions of these values. the sample increases as the radio spectral index flattens. While a general trend does exist, it is worth noting that the entire sample lies well above the z 0 main sequence. The minimum and mean specific star formation rates among the sample are a factor of 2.5 and 15 times larger than the z 0 main sequence value, respectively. However, many sources have radio spectral indices consistent with normal star-forming galaxies (i.e., α 0.8; Condon 1992). Thus, it seems that a flat radio spectral index does indicate that a source is above the main α is correlated with radio extent... form their stars in warm, compact, optically thick regions Fig. 10. IRS spectra of Mrk 52, NGC 7714, NGC 1222, NGC 7252, NGC 2146, NGC 520, NGC 3628, and NGC 4945 arranged to illustrate the gradual effect of increasing silicate absorption from top to bottom. The flux densities F k have been arbitrarily scaled for better comparison. increasing optical depth (Murphy et al. 2013) Fig. Fig. 6 to and to th extinctio malized starbur emissi to NG depres cate ab found Am (botto far the et al. 2 depth i depend strong

47 (3) The CO Spectral Line Energy Distribution - Mrk 231 Transitions up to J = observed Model: dense gas clump in a 560 pc radius star-forming disk exposed to UV + X-rays from an AGN heating the inner 160 pc. (van der Werf et al. 2010)

48 The Herschel-ALMA Overlap Band 8 Band 9 Band 10 Early Science Full Science Mrk 231 (van der Werf et al. 2010)

49 (4) ALMA observations of IIZw μm far-uv near-ir mid-ir 5 kpc CO(6 5) >95% of the emission centered on a single, resolved source If the molecular gas is distributed in a rotating disk, M dyn = 3.3 x 10 9 M sun (Inami et al. 2010; Stierwalt et al. 2013)

50 ALMA observations of IIZw μm far-uv near-ir mid-ir 5 kpc Source LIR L size pc μir L kpc -2 IIZw096 7x x x10 12 Orion core 2x x10 12 CO(6 5) M82 3x x75 9x10 11 (Inami et al. 2010; Stierwalt et al. 2013)

51 outflows: e.g., SMA results Dec. offset [arcsec] Dec. offset [arcsec] (a) Arp 220 HCO + (4-3) 0.33" x 0.28" 300 pc (c) Arp 220 CO(3-2) 0.34" x 0.28" R.A. offset [arcsec] (b) Arp 220 HCO + (3-2) 0.45" x 0.34" 300 pc (d) Arp mm 0.34" x 0.28" 300 pc R.A. offset [arcsec] Intensity [mjy beam -1 ] Arp 220 E HCO + (4-3) 1 σ HCO + (3-2) 1 σ CO(3-2) CO(3-2), 0.5" data 1 σ Velocity (radio, LSR) [km s -1 ] HCN(4-3) Velocity Intensity [mjy beam -1 ] Arp 220 W HCO + (4-3) 1 σ HCO + (3-2) 1 σ CO(3-2) CO(3-2), 0.5" data 1 σ HCN(4-3) Velocity Velocity (radio, LSR) [km s -1 ] gas disk has an inner region with significant outflow motion and outer region dominated by rotation dense absorbing gas deep with the gas disk source of acceleration - mechanical energy from supernovae or radiation pressure from an AGN (Sakamoto et al. 2009)

52 Summary U\LIRGs have complex substructures which vary as a function of wavelength Mid-IR diagnostics has provided insight to the relative importance of starburst and AGN to the IR output of U/ LIRGs At the high luminosity end, the star formation in U/LIRGs is compact and highly dust-enshrouded ALMA will enable the study of the star-forming molecular gas and dust, the importance of starburst and AGN heating to the chemistry observed in molecular clouds, the extent of the star-forming regions, the feedback in the form of molecular outflows