Abstract
We perform an exploratory study of the physical properties of accretion flows and jets in low-luminosity active galactic nuclei (LLAGNs) by modelling the spectral energy distributions (SEDs) of 12 LLAGNs in low-ionization nuclear emission-line regions (LINERs). These SEDs we constructed from high-resolution radio, X-ray and optical/ultraviolet (UV) observations of the immediate vicinity of the black hole. We adopt a coupled accretion-jet model comprising an inner advection-dominated accretion flow (ADAF) and an outer standard thin disc. We present best-fitting models in which either the ADAF or the jet dominates the X-ray emission.Six sources in our sample display an optical-UV excess with respect to ADAF and jet models; this excess can be explained as emission from the truncated disc with transition radii 30-225 RS in four of them. In almost all sources the optical emission can also be attributed to unresolved, old stellar clusters with masses ̃107-108 M⊙. We find evidence for a correlation between the accretion rate and jet power and an anticorrelation between the radio loudness and the accretion rate. We confirm previous findings that the radio emission is severely underpredicted by ADAF models and explained by the relativistic jet. We find evidence for a non-linear relation between the X-ray and bolometric luminosities and a slight IR excess in the average model SED compared to that of quasars. We suggest that the hardness of the X-ray spectrum can be used to identify the X-ray emission mechanism and discuss directions for progress in understanding the origin of the X-rays.
| Original language | English (US) |
|---|---|
| Article number | stt2388 |
| Pages (from-to) | 2804-2827 |
| Number of pages | 24 |
| Journal | Monthly Notices of the Royal Astronomical Society |
| Volume | 438 |
| Issue number | 4 |
| DOIs | |
| State | Published - Mar 1 2014 |
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All Science Journal Classification (ASJC) codes
- Astronomy and Astrophysics
- Space and Planetary Science
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Spectral models for low-luminosity active galactic nuclei in LINERs : The role of advection-dominated accretion and jets. / Nemmen, Rodrigo S.; Storchi-Bergmann, Thaisa; Eracleous, Michael.
In: Monthly Notices of the Royal Astronomical Society, Vol. 438, No. 4, stt2388, 01.03.2014, p. 2804-2827.Research output: Contribution to journal › Article
TY - JOUR
T1 - Spectral models for low-luminosity active galactic nuclei in LINERs
T2 - The role of advection-dominated accretion and jets
AU - Nemmen, Rodrigo S.
AU - Storchi-Bergmann, Thaisa
AU - Eracleous, Michael
PY - 2014/3/1
Y1 - 2014/3/1
N2 - We perform an exploratory study of the physical properties of accretion flows and jets in low-luminosity active galactic nuclei (LLAGNs) by modelling the spectral energy distributions (SEDs) of 12 LLAGNs in low-ionization nuclear emission-line regions (LINERs). These SEDs we constructed from high-resolution radio, X-ray and optical/ultraviolet (UV) observations of the immediate vicinity of the black hole. We adopt a coupled accretion-jet model comprising an inner advection-dominated accretion flow (ADAF) and an outer standard thin disc. We present best-fitting models in which either the ADAF or the jet dominates the X-ray emission.Six sources in our sample display an optical-UV excess with respect to ADAF and jet models; this excess can be explained as emission from the truncated disc with transition radii 30-225 RS in four of them. In almost all sources the optical emission can also be attributed to unresolved, old stellar clusters with masses ̃107-108 M⊙. We find evidence for a correlation between the accretion rate and jet power and an anticorrelation between the radio loudness and the accretion rate. We confirm previous findings that the radio emission is severely underpredicted by ADAF models and explained by the relativistic jet. We find evidence for a non-linear relation between the X-ray and bolometric luminosities and a slight IR excess in the average model SED compared to that of quasars. We suggest that the hardness of the X-ray spectrum can be used to identify the X-ray emission mechanism and discuss directions for progress in understanding the origin of the X-rays.
AB - We perform an exploratory study of the physical properties of accretion flows and jets in low-luminosity active galactic nuclei (LLAGNs) by modelling the spectral energy distributions (SEDs) of 12 LLAGNs in low-ionization nuclear emission-line regions (LINERs). These SEDs we constructed from high-resolution radio, X-ray and optical/ultraviolet (UV) observations of the immediate vicinity of the black hole. We adopt a coupled accretion-jet model comprising an inner advection-dominated accretion flow (ADAF) and an outer standard thin disc. We present best-fitting models in which either the ADAF or the jet dominates the X-ray emission.Six sources in our sample display an optical-UV excess with respect to ADAF and jet models; this excess can be explained as emission from the truncated disc with transition radii 30-225 RS in four of them. In almost all sources the optical emission can also be attributed to unresolved, old stellar clusters with masses ̃107-108 M⊙. We find evidence for a correlation between the accretion rate and jet power and an anticorrelation between the radio loudness and the accretion rate. We confirm previous findings that the radio emission is severely underpredicted by ADAF models and explained by the relativistic jet. We find evidence for a non-linear relation between the X-ray and bolometric luminosities and a slight IR excess in the average model SED compared to that of quasars. We suggest that the hardness of the X-ray spectrum can be used to identify the X-ray emission mechanism and discuss directions for progress in understanding the origin of the X-rays.
UR - http://www.scopus.com/inward/record.url?scp=84894357249&partnerID=8YFLogxK
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U2 - 10.1093/mnras/stt2388
DO - 10.1093/mnras/stt2388
M3 - Article
AN - SCOPUS:84894357249
VL - 438
SP - 2804
EP - 2827
JO - Monthly Notices of the Royal Astronomical Society
JF - Monthly Notices of the Royal Astronomical Society
SN - 0035-8711
IS - 4
M1 - stt2388
ER -