Studying AGN & QSOs with HST

Transcription

1 Studying AGN & QSOs with HST

2 AGN/Quasars with HST Ac9ve galaxies and quasars: studies of the ac9ve phenomena themselves, and of the proper9es of the host galaxies that harbor them. AGN: A galaxy nucleus that shows evidence for accre9on onto a supermassive black hole

3 Taxonomy UV/opt/IR luminosity: Quasars (Lnuc > Lgal) Strong AGN (Lnuc < Lgal) Weak AGN (Lnuc << Lgas) Radio Luminosity (jet power) Radio Quiet (LR < 1e 4 Lopt) Radio Loud (LR > 0.1 Lopt) Viewing Angle Broad + Narrow Lines (can see BLR) (type 1) Narrow lines only (can t see BLR) (type 2)

4 Viewing perspec9ve BLR ~ pc NLR 10 pc 1 kpc Wadsmorth Publishing

5 Quasars & QSOs Most are found between z = 2 4 Now more than 60 at z > 5.7. Most distant z ~ 7 Typical QSO L > x L MW Triggered by gas flowing on SMBH at a high rate Currently rate of gas consump9on must be much less

6 QSO spectrum QSO con9nuum rela9vely flat Broad emission features produced by the QSO (near SMBH and accre9on disk) (highly redshifed) Can be Intrinsic absorp9on lines (CIV) Intervening absorp9on lines

7 Co evolu9on of SMBHs and Galaxies M bh σ Rela9on Ferrarese & Merris 2000, Gebhardt 2000, Tremaine 2002 β = / 0.29 α = σ 0 = 200 km/s [local quiescent galaxies] Kormendy & Ho 2013 (GOOD REVIEW!!) Magorrian 98 rel n

8 Other correla9ons should exist? Stanley

9 Black Hole Mass Determina9on: 1) Reverbera9on Mapping Temporal offsets between con9nuum and emission line variability allow one to determine the distance from the BH to the broad emission line region (BLR) R Blandford & McKee 1982 Peterson 1993

10 Courtesy M. Bentz r = characteris9c size of the BLR

11 NGC 4151 The observable UV/op9cal con9nuum and ionizing con9nuum vary in phase. (~ 6 days = r/c) Bentz

12 Reverbera9on cont d Assuming the emission lines are broadened primarily by the virial gas mo9ons in the graivta9onal poten9al: Line width, V from BLR broad emission line + assump9on of virializa9on at BLR M BH = f r V 2 / G

13 2) Single epoch virial BH mass es9mators Reverbera9on mapping reveals correla9on between BLR size, R, and luminosity of con9nuum (Kaspi 2000, 2005) R α L ϒ, ϒ = 0.5 BLR Size Virial Theorem : M = f v 2 R/G Kaspi 2005 FWHM of the broad Hβ (MgII) Means can find masses using single epoch spectra a =0.91, b = 0.5, c = 2 Vestergaard & Peterson 2006 Feng Shen

14 Bulge Velocity dispersion Emission line surrogates from the NLR : [OIII] line Assumes NLR gas orbits in the gravita9onal poten9al of the host galaxy bulge Green & Ho 2005 showed that σ OIII tends to overpredict σ * (contamina9on from AGN) Lower ioniza9on lines OII, SII also work (but large scaser) New results: Shen

15 Evolu9on with Z? When are the rela9ons established? Line is the local rela9on from Tremaine 2002 Colored points are average M BH and σ per redshif bin Blue HO3: 0.1 < z < 0.8 Hβ for M BH, OIII for σ open circles Red MO2 : 0.4 < z < 1.35 Mg II for M BH, OII for σ closed circles Seems to suggest posi9ve evolu9on (BH growth precedes that of bulge) Huge debate about this. Salviander 2013 SDSS DR7

16 SDSS Reverbera9on Mapping project 0.1 < z< 1.09 Spectroscopically monitor 88 QSOs with the SDSSIII BOSS spectrograph New σ * measurements decomposed spectra into host and QSO Rela9on *does* exist at high z Slope is much shallower than local rela9on bias No strong evolu9on with redshif, but the rela9on may get flaser at higher z Shen

17 Tight Rela9ons Mean: BH affects galaxy structure at scales that are much larger than its own sphere of influence from gravity alone ~ 100 pc vs Rbulge = 2 Kpc SMBHs and Galaxy coevolu9on is established at z ~ 1

18 Exploring Galaxy Assembly & SMBH Growth with HST A) What are the hosts of QSOs? B) What triggers QSOs? C) SMBHs & Galaxy coevolu9on? What regulates the correla9ons (M sigma)?

19 A) QSO Hosts? HST showed that QSO hosts are galaxies

20 B) What Triggers QSOs? Cause must be more common at high z Need to explain co evolu9on of SMBH and galaxy Two Leading theories Mergers (major or minor) Gravita9onal instabili9es in galaxy disks

21 Hopkins+ 2006, H op kins et a l. Merger Hypothesis: F IG. 1. An sc he ma ti c ou t li ne o f t h e p h as es of gro wth i n a t y pi ca l g alax y u n d erg oin g a gas -rich majo r m erger. Im age Cre di t: (a ) NOAO/ AUR A/NS F; (b ) R E U p ro g ra m /NOAO/AURA/ NSF; (c ) NAS A/ST ScI/AC S Sci en ce Tea m; (d) Op ti ca l (le ft): NA SA/ STScI/R. P. van d er M arel & J. Gerssen ; X-ray (rig h t): NASA/C XC /MP E /S. Ko m oss a et al.; (e) Left : J. B ah c al l/m. Disn e y/ NASA; Ri g h t: Gemin i Ob serv ato ry /NS F/Un iv ersity o f Hawaii In stitu te fo r As tro no m y; (f) J. B ah call/m. Dis n ey /NASA; (g ) F. Sch weizer (CIW / DTM ); (h ) NOAO/ AURA/ NSF.

22 Gravita9onal Instabili9es High z gas disks have high gas densi9es, con9nuously fed by streams (50% gas frac9ons) Gas disks are unstable Q ~1, forming giant star forming clumps and transient perturba9ons Gravita9onal torques from these perturba9ons lead to inflows Inflow rates ~10 M /yr (1+z) 3/2 Ends when cosmological accre9on rate declines and the system become stellar dominated Bournaud (2011), Dekel (2009)

23 Differen9a9ng between the two scenarios with HST: high spa9al resolu9on imaging Predict different host galaxy morphologies Distorted disks with 9dal structures VS Star forming disk galaxies composed of clumpy disks and growing spheroids Quiescent merger remnant vs Star forming Disk (Red/Green sequence vs Blue Cloud) Predict different distribu9ons of cool gas and SF in the environment of SMBH

24 QSO with shells

25 Lack of Evidence for Mergers? QSOs found in CANDELS about normal looking galaxies (except for top lef) 26 out of 30 showed no obvious signs of mergers

26 Abstract Proposal A Facts Problem Goal HST Fixes Problem Broader Impact

27 Proposal A Strengths: The proposers have iden9fied very interes9ng objects with spa9ally resolved host galaxies as part of their survey of very bright LBGs. Because of their spa9ally resolved nature, study of the host morphology seems natural. Weaknesses: On the other hand, with only three targets, 12 orbits seems like a fairly large investment. Furthermore, the proposal lays out extremely lofy goals (e.g., find evidence of cold flows) that seem difficult to achieve with only measurements of host galaxy morphology. It is not clear why these targets are par9cularly suited to be the smoking gun of cold flows, nor how exactly the proposed observa9ons would provide compelling evidence of these flows.

28 C) SMBH & Galaxy Co Evoln at high redshif ~ 40 known QSOs at z > 6 M bh > 1e9 M Universe < 1 Gyr old Host galaxies of QSOs at z ~ 6 should have ULIRG proper9es (verified by CO, Submm observa9ons) What are their SFRs? Li et al. 2007: several major mergers, forms the SMBH at z ~ 6.5 in the most massive halo in a 3 Gpc 3 box Environment?

29 New challenge M bh = (1.24 +/ 0.19) x M Wu (!!! 1e9 was hard!!!)

30 Mass in context Most massive QSO SMBH at z > 6.3 Isn t super high z, but *much more massive* (Originally thrown out since bright enough to be in 2MASS!) May suggest that BHs grow faster than hosts at high z Wu

31 Proposal B Strengths: This is a fascina9ng object that deserves to be studied in more detail. The proposed science goals can provide valuable insight into the proper9es of the host galaxy in the very early universe, reioniza9on, and early structure forma9on. The panel appreciated the discussion of the previously successful method of PSF subtrac9on. Weaknesses: The coordinated parallels were not strongly jus9fied. It was unclear how representa9ve this extraordinary object is and how to interpret the observa9ons. This target is from the op9cally selected SDSS sample which is incomplete; a discussion of whether similarly massive candidates may be in IR surveys such as WISE would have been helpful. There was also some concern that the PSF subtrac9on would not be as successful due to, e.g. Poisson noise, because the target is brighter than the example in the proposal. The achievability of this from the ground with AO was not ruled out.