RADIATIVELY INEFFICIENT ACCRETION DISKS IN LLAGN WHERE TO LOOK FOR THEM

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RADIATIVELY INEFFICIENT ACCRETION DISKS IN
LLAGNWHERE TO LOOK FOR THEM

• Marco Chiaberge
• Space Telescope Science Institute
• and INAF-IRA
• Alessandro Capetti INAF Torino Observatory
• Duccio Macchetto STScI-ESA
• Roberto Gilli INAF- Bologna Observatory
• Bill Sparks - STScI

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• THE HST VIEW OF LLAGN

The nuclei of LLRG, Seyferts and LINERS Where to
look for RIAFs
2. NGC 4565 Are we finally detecting RIAF in
the optical?
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• Accretion disks
• standard Shakura-Sunyaev
• efficient radiative cooling ? L/Mc2 0.1
• geometrycally thin, optically thick disks
• L lt LE 1.3 x 1038 M/Msun erg/s

.
Observed in QSO and Seyfert galaxies SED Blue
bump IR bump (hot dust)

• RIAF (ADAF, CDAF, ADIOS, etc)
• m Mc2/ LE lt mcrit , ????????
• L/ LE ltlt 1
• geometrically thick, optically thin

.
.
.
Where can we find them? SXT?, Galactic center?,
LINERS?, LLRG?, Seyferts?
SED synchrotron peak, IC peak(s), Bremsstrahlung
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The Galactic center - ADAF model (with winds)
Quataert Narayan 1999
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LLAGN
Nearby galaxies with some evidence for AGN
activity Faint
compact radio cores L(H?) lt
1040 erg s-1 (Ho et al. 1997)
Radio quiet
Radio loud
Low Luminosity Radio Galaxies (LLRG) (FR I
morphology)
OIII / OII lt 1
LINERs
Low Ionization Nuclear Emission-line Regions
OIII / OII gt 1
Seyferts
(e.g. Heckman et al. 1980, Kewley et al. 2006)
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THE RADIO-OPTICAL CORE CORRELATION
OF FR I NUCLEI
For MBH 108 M? the nuclei set the upper
limit to the disk luminosity Ldisk lt 10-5 Ledd
Chiab, Capetti Celotti 1999, Capetti et al.
2002, Verdoes-Kleijn et al. 2001
NON-THERMAL SYNCHROTRON EMISSION FROM THE BASE OF
THE JET
?
Slope 0.9 ? 0.1 ??r - o 0.6 - 0.9
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LLAGN in the local universe
LINERs d lt 19 Mpc from the Palomar
sample of nearby galaxies
21/25 have HST images
SEYFERT 1 data from Ho Peng 2001
Palomar sample (dmed 20 Mpc)
CfA sample (dmed 80 Mpc)
25/32 have HST images
FR I radio galaxies from the 3CR catalog
THE LOCAL AGNs ARE WELL REPRESENTED BY THESE 3
SAMPLES
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Low luminosity radio galaxies (FRI) are
unobscured
(D. Macchettos talk) They do
not host radiatively efficient accretion disks
BUT
Synchrotron radiation from the jet dominates
(at all wavelengths!!)
WHAT ABOUT THE OTHER CLASSES OF LLAGN
IN THE LOCAL UNIVERSE?
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Compact radio cores in LINERs and Seyferts

Unresolved on the mas scale
TB gt 108 K
Flat
radio spectrum ?? 0.0 - 0.6 (F???-?)
The radio
cores are variable
Radio cores are synchrotron emission from a
jet (Nagar et al 2002, Falcke et al.
1999,
Anderson et al. 2004)
SIMILAR TO THE CORES OF RADIO GALAXIES
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LLAGN - Seyfert 1 nuclei
NGC 5033 - HST WFPC2 - V band
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LLAGN - LINER nuclei
Unresolved nuclei in 40 of the objects
NGC 4278 - HST WFPC2- I band
NGC 4589 - HST WFPC2- I band
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15
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LLAGN IN THE RADIO-OPTICAL PLANE
Sy1
Radio quiet
FR I
Radio loud
LINERs
Chiab et al 2005
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Elliptical galaxies with core profiles and
compact radio emission
Balmaverde Capetti 2006
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BLACK HOLE MASS VS. RADIO LOUDNESS
RL
Radio-loud AGN in the SDSS have MBHgt 108
Msun (Mc Lure and Jarvis 2004)
FR I
SY 1
RQ
LINER
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ACCRETION EFFICIENCY VS. RADIO LOUDNESS
LEdd 1.3 x 1038 (MBH/M?) erg s-1
FR I
SY 1
LINERs
SY1 NUCLEI ARE NOT RL
o
RIAF?
The nuclear radio loudness traces the emission
process
RL
RQ
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• NGC 4565 (Chiab, Gilli, Macchetto Sparks
  2006)
• Low luminosity Seyfert d 9.7 Mpc
• Included in the Ho et al. 1997 sample (Palomar)
• Moderate absorption in the X-rays NH 2.5 x
  1021 cm-2
• Only NARROW emission lines (Seyfert 2)
• Compact 5GHz radio emission (VLBI)
• Flat ?0.15 radio spectrum

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IR 1.6 ?m NICMOS
OPTICAL (4500 A) WFPC2
NGC 4565 AS SEEN WITH THE HUBBLE SPACE TELESCOPE
U-BAND 3300 A ACS/HRC
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1. What is the origin for absorption?
NH 2.5 x 1021 cm-2
AV 1.2
NGC 4565 is a spiral galaxy seen almost edge-on
?? 10º In the Galaxy at b 10º AV
1.0-2.0
No need for nuclear obscuration
NGC 4565 is an unobscured Seyfert 2
(e.g. Laor 2003, Elitzur Sholsman 2006)
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NGC4565 in the radio-optical plane
Optical excess w.r.t. synchrotron emission Optica
l radiation from the accretion process?
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NGC 4565 BH mass 2.8 x 107 Msun
Low L /Ledd low radiative
efficiency and/or low
accretion rate
RQ
RL
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SED OF NGC 4565 COMPARED TO OTHER SEYFERT
GALAXIES
The SED is unusual No IR thermal excess No blue
bump
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• NGC4565 IN THE FUNDAMENTAL PLANE
• OF BLACK HOLE ACTIVITY
• (Merloni et al 2003, Falcke et al. 2004)

QSOs

• Correlations are
• to be used with care!!
• (Chiaberge, in prep)

LLAGN
XRBs
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CONCLUSIONS

• FRI RADIO GALAXIES NUCLEI ARE JET DOMINATED
• IF THEY HOST A RIAF, WE CANT DETECT IT

2. WE SHOULD SEARCH FOR RIAFs AMONG LLAGN WITH
RADIO QUIET NUCLEI (SEYFERT AND LINERS)
IN HOW MANY OBJECTS CAN WE DETECT THEM?
3. IN NGC 4565 WE ARE MOST LIKELY OBSERVING (FOR
THE FIST TIME?) AN ADAF-LIKE (RIAF) ACCRETION
PROCESS IN THE OPTICAL
4. NGC4565 IS AN UNOBSCURED SY2 unobscured
Sy2 do exist