THE RELATION OF OPTICAL/ULTRAVIOLET AND X-RAY EMISSION IN LOW-LUMINOSITY ACTIVE GALACTIC NUCLEI

Journal Article · Sat Oct 01 04:00:00 EDT 2011 · Astrophysical Journal

DOI:https://doi.org/10.1088/0004-637X/739/2/64; COUNTRY OF INPUT: INTERNATIONAL ATOMIC ENERGY AGENCY (IAEA)· OSTI ID:21587493

We study the relation of optical/UV and X-ray emission in the low luminosity active galactic nuclei (LLAGNs), using a sample of 49 sources including 28 local Seyfert galaxies and 21 low-ionization nuclear emission-line regions with optical/UV spectral luminosity at wavelength {lambda} = 2500 A, 23.0 {<=} log L{sub {nu}(2500A)}(erg s{sup -1} Hz{sup -1}) {<=} 27.7, and X-ray spectral luminosity at 2 keV, 20.5 {<=} log L{sub {nu}(2keV)} {<=} 25.3. Strong correlations are found between the X-ray luminosity and the optical/UV-to-X-ray index, {alpha}{sub ox}, with the optical/UV luminosity, with slopes very similar to the findings for the luminous AGNs in previous works. The correlation between {alpha}{sub ox} and L{sub {nu}(2keV)} is very weak, as is that found for the luminous AGNs in the majority of previous similar works. We also study the relation between {alpha}{sub ox} and the Eddington ratio L{sub bol}/L{sub Edd} for our sample and find a significant anti-correlation for the sources with L{sub bol}/L{sub Edd} {approx}< 10{sup -3}, which is opposite to the correlation between the two variables for the luminous AGNs. Using the advection-dominated accretion flow (ADAF) model, we roughly reproduce this anti-correlationship for the two variables for the LLAGNs. This result strongly supports the ADAF as a candidate for the accretion mode in LLAGNs.

• OSTI ID: 21587493
• Journal Information: Astrophysical Journal, Journal Name: Astrophysical Journal Journal Issue: 2 Vol. 739; ISSN ASJOAB; ISSN 0004-637X
• Country of Publication: United States
• Language: English

Related Subjects

79 ASTRONOMY AND ASTROPHYSICS
ACCRETION DISKS
CORRELATIONS
ELECTROMAGNETIC RADIATION
EMISSION
GALAXIES
GALAXY NUCLEI
IONIZING RADIATIONS
LUMINOSITY
OPTICAL PROPERTIES
PHYSICAL PROPERTIES
RADIATIONS
SEYFERT GALAXIES
ULTRAVIOLET RADIATION
X RADIATION