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)

MBH=2.5x106 Msun

LX=1036 erg/s

=3x10-9 LEdd

stellar mass loss:~10-6 Msun/yr

Bondi accretion:~3x10-7 Msun/yr

Lacc=(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

Mç

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 – TB~108K -- and sometimes have jetlike structures.

Terashima & Wilson (2003)

Unresolved (1”) nuclear X-ray source...

...in about 1/2 of LINERs...

Ho et al. (2001)

Ho et al. (2001)

...with flux falling ~ on AGN L(Ha) vs LX 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 404 NGC 3642 NGC 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 2002-2003 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

660 pc

3C 75

7 kpc

NGC 6240

700 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

Lbol/LEdd

Ho (2002)