The ubiquitous UV murmurs of sleeping supermassive BHs Dani Maoz With: Neil Nagar, Heino Falcke, Andrew Wilson

Peterson et al. (2004)

High-L accretion physics: (geometrically ) thin accretion disk

Manners 2002 accretion disk?

Kormendy & Gebhardt 2001

M32; Ho, Terashima, & Ulvestad (2003) M BH =2.5x10 6 M sun L X =10 36 erg/s =3x10 -9 L Edd stellar mass loss: ~10 -6 M sun /yr Bondi accretion: ~3x10 -7 M sun /yr L acc =(    erg/s

ADAF CDAF ADIOS Outflow “RIAF” Ho (2003) if very large or very small, thermal instability, high T, inefficient cooling, other accretion solutions: geometrically thick accretion disks

What is the connection between active and “normal” galactic nuclei? (AGNs and NGNs): How can SMBHs sleep so quietly?

One way to progress: study the subtle signs of activity from “normal” nuclei demographics, accretion physics SMBH history

The most common manifestation of (possibly) non-stellar nuclear activity is LINERs

QSO

Seyfert 1

Seyfert 2

LINER (low ionization nuclear emission-line region)

SDSS; Kaufmann et al. (2003)

LINERs are very common in bulges Many of our best friends are LINERs…

M87

NGC 4594

At least 1/2 of LINERs have a compact radio source.... Nagar et al. (2002)

...at least 1/2 of which are time variable... Nagar et al. (2002)

Nagar et al. (2003)...and at milli-arcsec resolution the cores remain unresolved – T B ~10 8 K -- and sometimes have jetlike structures.

Terashima & Wilson (2003) Unresolved (1”) nuclear X-ray source...

...in about 1/2 of LINERs... Ho et al. (2001)

...with flux falling ~ on AGN L(Ha) vs L X relation.

~1/4 of LINERs have broad (variable) Ha wings NGC 4579; Barth et al. (2001)

But.... -what about all those “~1/2’s”? -many LINERs have not revealed AGN signatures

Do LINERs have anything to do with the BH? LINERs can be excited by: Photoionization by an AGN Ferland & Netzer (1983); Halpern & Steiner (1983); Filippenko & Halpern (1984); Ho et al. (1993) Photoionization by stars – WR stars: Terlevich & Melnick (1985); O-stars: Filippenko & Terlevich (1992); Shields (1992); Schultz & Fritsch (1994) Young starburst: Barth & Shields (2000) Post-AGB stars: Binnette et al. (1994); Taniguchi et al. (2000) Shocks Koski & Osterbrock (1976); Heckman (1980); Aldrovandi & Contini (1984); Dopita & Sutherland (1996)

Maybe SMBHs and LINERs are both common in galactic nuclei but an optical LINER spectrum is not directly related to the accretion process.

LINER definition based on optical emission lines; Excitation determined by far-UV light; Look in the UV!

Nuclear UV sources in nearby LINER galaxies: 330 nm 250 nm

NGC 404NGC 3642NGC 4203 M81 NGC 4258 NGC 4736

Nucleus is obscured by dust in all LINERs w/0 UV nucleus; Probably all LINERs have UV nucleus Pogge et al. (2000)

UV spectrum of LINERs NGC 4579; Barth et al. (1996)

Maoz et al. (1998)

NGC 1741B starburst

So, how to distinguish stellar from nonstellar? VARIABILITY! (defining characteristic of AGNs) Monitor in UV a sample of LINERs:

Snapshot Monitoring with HST/ACS/HRC in at 2500 Ang and 3300 Ang

The sample: (all) 17 LINERs with known UV nuclei L(UV)~10^(39-41) erg/s Includes all kinds: LINERs 1 / 2, radio / X-ray detected / undetected, AGN-like / starburst-like, pure / transition types.

Big worry: detector stability Boffi et al. 2004: ACS stable in UV to < 1% !

Results: F330 f250 “historical” (5~10 yr earlier) level

Summary of results: 1. 11/15 vary significantly on short (month) timescales, typical amplitudes ~10% 2. Correlated variations in 2500 A and 3300 A 3. Long timescale (years-decade) variations common, amplitudes factor few 4. Only 3/17 vary neither on long or short timescales, but even these may be due to sparse sampling 5. All LINER types vary

Conclusion: LINERs are indeed genuine signposts of nonstellar activity (i.e., AGNs). SMBHs in most “normal” galaxies are producing (in one way or another) a LINER spectrum. Variable UV flux gives lower limit on AGN UV luminosity – can constrain accretion models

Nagar et al. (2001) ADAFs predict wrong radio slope; radio emission probably dominated by jets Also, wrong slope in X-rays Terashima & Wilson (2003) Perhaps UV is also from jets?

NGC 4736: a binary/merging BH? b nucleus

6 60 pc

3C 75 7 kpc

NGC pc

Conclusions: 1.Most LINERs are excited by some nonstellar phenomenon near the SMBH (accretion, jets) 2. Sharpens demographic picture and allows probe of accretion process, hence SMBH growth history 3. Possible detection of closest/nearest binary AGN

Ho, Filippenko, & Sargent 1993

radio loudness L bol /L Edd Ho (2002)