today : our galactic nucelus Ultra-Luminous IR Galaxies (ULIRGs) high-z submillimeter galaxies and QSO’s starbursts and AGN fueling Galactic center circumnuclear disk - CND Paschen α (stars removed) Pα ==> ionized mini-spiral 1 pc BH (Sgr A* ) : 4x106 M¤ L < 106 L¤ ionized spiral (Paschen α) dense H2 clumps (HCN) CND : 1 – 3 pc radius MH2 ~ 5x105 (~ GMC) n ~ 107 – 8 cm-3 (tidally stable) τorbit = 105 yr , τdyn = 104 yr no evidence of SF ? !! Christopher etal 2005 1 pc luminous IR Galaxies (Sanders & Mirabel 96, ARAA) Annual Reviews ULIRGS HyperLIRGS 9:20 12-13 SANDER2 AR12-18 10 L¤ Arp220, Mrk 231, NGC6240 >1013 L¤ IR1520+32 1988ApJ...325...74S 1998 z = 0 Galaxy Luminosity functions 756 SANDERS & MIRABEL optical –2 IRAS BGS IRAS 1Jy ULIGs Mrk Seyferts Mrk Starburst ! cDs Normal galaxies –4 –3 –1 log " (Mpc Mbol ) PG QSOs ! ! –6 IR –8 –10 9 10 11 log L bol 12 13 (L . ) Figure 1 The luminosity function for infrared galaxies compared with other extragalactic objects. References: IRAS RBGS (Sanders et al 1996a), IRAS 1-Jy Survey of ULIGs (Kim 1995), PalomarGreen QSOs (Schmidt & Green 1983), Markarian starbursts and Seyfert galaxies (Huchra 1977), and normal galaxies (Schechter 1976). Determination of the bolometric luminosity for the optically IR optical LFIR high luminosity tail: Φ ∝ L-2.35 ρ (z) ∝ (1+z)5 ± 2.5 HST ACS Bi imaging – Evans etal 2008 LIR Observed SEDs Low-z ULIRGs Sanders etal 88 LIR / MH2 LUMINOUS INFRARED GALAXIES 773 Table 3 IRAS galaxy properties versus L ir 10.5–10.99 No. of objectsa Morphology echnology on 03/04/12. For personal use only. Separationb Opt Spectra L ir /L B c L ir /L �CO c merger close pair single (?) [kpc] Seyfert 1 or 2 LINER H II [L ⊙ (K km s−1 pc2 )−1 ] 50 12% 21% 67% 36. 7% 28% 65% 1 37 11.0–11.49 11.5–11.99 log(L ir /L ⊙ ) 50 32% 36% 32% 27. 10% 32% 58% 5 78 30 66% 14% 20% 6.4 17% 34% 49% 13 122 12.0–12.50 40 95% 0% 5% 1.2 34% 38% 28% 25 230 a Objects in the IRAS BGS plus additional ULIGs from Kim & Sanders (1996). Mean projected separation of nuclei for mergers and close pairs only. c Mean values. b higher L è merging doubleappears nuclei in molecularincreasing gas; at the lowfreq. end ofofthis range the & luminosity to be domincreasing fraction with AGN-like emission lines inated by starbursts with Seyferts becoming increasinglyopt. important at higher luminosities. Those objects that reach the highest infrared luminosities, L ir > 1012 L ⊙ , contain exceptionally large central concentrations of molecular gas; because of heavy dust obscuration it is hard to distinguish the relative roles of starburst and AGN activity, although the conditions are clearly optimal for fuel- Low-z ULIRGs : LIR / MH2 èSF efficiency NGC 6240: merger of 2 massive disk galaxies w/ xray sources (AGN) in each nucleus HST B and I bands (F450W, F814W) with Hα Near-infrared K band image, Keck adaptive optics XRAY (CXO) 0.5 – 1.5 kev 5.4 arcsec 1.5 – 5 kev 5 – 8 kev Arp 220 distance 77 Mpc LIR ~ 2x1012 L¤ (HST/ACS) (Subaru/Suprime-cam) Arp 220 (@77 Mpc) -- L = 2x1012 L¤ double nuclei – 300 pc apart 3x109 M¤ H2 on each, counter-rot. HST : 1.1, 1.6, 2.2μm 1 arcsec = 300pc inclined , opaque disk obscuring nuclear star cluster Arp 220 -- mm-wave imaging : CO and dust counter-rotating nuclear disks Sakamoto etal 1999 Arp 220 HCN (4-3) from ALMA project with Swarnima total HCN flux east : 91 Jy km/s west : 199 Jy km/s mean velocity è counter-rotating nuclei Arp 220 properties Arp 220 E Arp 220 W size < 100 pc 120 x 70 pc TB(CO) 38 K 37 K ΔV 540 km/s 480 km/s Mdyn 4x109 M¤ 3x109 M¤ Mgas ~2x109 M¤ ~2x109 M¤ total Mgas 5x109 M¤ high gas mass fraction high area filling – not cloudy filled gas disks AV ~ 2000 !! mag perp. to disk maximal rate of SF : gasè* on a dynamical timescale MISM / τorbit è 104 Msun yr-1 -- Arp 220 if SF efficiency high or rapid AGN accretion L would be higher what’s wrong ?? something is limiting SF ... nuclear starburst structure •  ISM dissipative => disk •  uniform (not cloudy) distribution observed ! V ~ 70 km / s " thickness,h ~ 20 # 50 pc (assuming hydrostatic equil.) rad. press. gravity self-regulating: SFR $" Prad. $" h$" density %" SFR % M L L & ' 2 and Prad ' 2 " max ~ 200 # 500 L( M R R dust radiation pressure limited SB : Frad. "L / c =! g 4#G"M L$ "L > 1 for > 500 (w/ dust abs. ! for 5µm) "M M$ Arp 220 -- ΣL / ΣM ~ 1012 / 2x109 ~ 500 L¤ / M¤ ==> radiatively self-regulated starburst can only avoid how ? moving out to high redshift ... molecular gas and dust at high z cumulative # per yr submillimeter galaxies – SMGs detected in dust continuum several classes of objects – most interesting high-z ULIRGs negative k-correction è easy to see higher z sliding up the RJ tail flux 2000ASPC..200...81H z=2 observed fluxes (arp 220) vs redshift 1 0 submillimeter galaxies – apparent dust temp. & IR luminosity easy to recognize lensed objects wide range of excitation in high z galaxies unlensed sources CO spatial maps w/ velocity field CO Maps Velocities some w/ rotation gradients some w/ high dispersion H2 contents at z ~2 Tacconi etal 2010 – sample of 23 massive spirals @ z = 1-3 (not IR or SF selected) 34% 44% fgas = MH2 / (MH2 + M* ) how to pick out starbursts ? timescales and concentration must be physically motivated ! e.g. specific SF rate , sSFR = SFR/M* = 1/τ* meaningless unless τ* compared w/ something e.g. τcosmic , τgalaxy prefer τISM = MISM/SFR if short compared to τ* or τgal, then bursting ISM – fundamental to rejuvenation and activity in galaxies SF, SN , AGN outstanding ?’s replenishment relationship of phases – mechanism of transformation star / planetary formation interesting astrophysics – shock front , turbulence , magnetic effects