J/A+A/619/A95 X-ray/UV ratio of AGN (Chiaraluce+, 2018)
The X-ray/UV ratio in active galactic nuclei: dispersion and variability.
Chiaraluce E., Vagnetti F., Tombesi F., Paolillo M.
<Astron. Astrophys. 619, A95 (2018)>
=2018A&A...619A..95C 2018A&A...619A..95C (SIMBAD/NED BibCode)
ADC_Keywords: Active gal. nuclei ; QSOs ; X-ray sources ; Ultraviolet
Keywords: galaxies: active - quasars: general - X-rays: galaxies
Abstract:
The well established negative correlation between the αOX
spectral slope and the optical/UV luminosity, a by product of the
relation between X-rays and optical/UV luminosity, is affected by a
relatively large dispersion. The main contributions can be variability
in the X-ray/UV ratio and/or changes in fundamental physical
parameters. We want to quantify the contribution of variability within
single sources (intra-source dispersion) and that due to variations of
other quantities different from source to source (inter-source
dispersion). We use archival data from the XMM-Newton Serendipitous
Source Catalog (XMMSSC, Cat. IX/50) and from the XMM-OM Serendipitous
Ultra-violet Source Survey (XMMOM-SUSS3, Cat. II/340). We select a
sub-sample in order to decrease the dispersion of the relation due to
the presence of Radio-Loud and Broad Absorption Line objects, and to
absorptions in both X-ray and optical/UV bands. We use the Structure
Function (SF) to estimate the contribution of variability to the
dispersion. We analyse the dependence of the residuals of the relation
on various physical parameters in order to characterise the
inter-source dispersion. We find a total dispersion of σ∼0.12
and we find that intrinsic variability contributes for 56 percent of
the variance of the αOX-LUV relation. If we select only
sources with a larger number of observational epochs (>2) the
dispersion of the relation decreases by approximately 15 percent. We
find weak but significant dependences of the residuals of the relation
on black-hole mass and on Eddington ratio, which are also confirmed by
a multivariate regression analysis of αOX as a function of UV
luminosity and black-hole mass and/or Eddington ratio. We find a weak
positive correlation of both the αOX index and the residuals
of the αOX-LUV relation with inclination indicators, such as
the FWHM(Hβ) and the EW[OIII], suggesting a weak increase of
X-ray/UV ratio with the viewing angle. This suggests the development
of new viewing angle indicators possibly applicable at higher
redshifts. Moreover, our results suggest the possibility of selecting
a sample of objects, based on their viewing angle and/or black-hole
mass and Eddington ratio, for which the αOX-LUV relation is as
tight as possible, in light of the use of the optical/UV-X-ray
luminosity relation to build a distance modulus (DM)-z plane and
estimate cosmological parameters.
Description:
We present the Reference sample of simultaneous UV and X-ray data
obtained matching the XMM-OM Serendipitous Ultra-violet Source Survey
(XMMOM-SUSS3, Page et al., 2012MNRAS.426..903P 2012MNRAS.426..903P, Cat. II/340) with the
MEXSAS2 Catalogue (Serafinelli et al., 2017FrASS...4...21S 2017FrASS...4...21S). The
latter is an upgrade of the Multi-epoch X-ray Serendipitous AGN Sample
(MEXSAS, Vagnetti et al., 2016, Cat. J/A+A/593/A55), derived from the
DR6 of the XMM-Newton Serendipitous Source Catalogue (Rosen et al.,
2016A&A...590A...1R 2016A&A...590A...1R, Cat. IX/50), identified with AGNs from SDSS DR7Q
(Schneider et al., 2010AJ....139.2360S 2010AJ....139.2360S, Cat. VII/26) and SDSS DR12Q
(Paris et al., 2017A&A...597A..79P 2017A&A...597A..79P, Cat. VII/279) quasar catalogues,
and provides black-hole mass, Eddington ratio and bolometric
luminosity derived from Shen et al. (2011, Cat. J/ApJS/194/45) and
Kozlowski (2017, Cat. J/ApJS/228/9). The Reference sample contains
data for 1095 AGN observed from 1 to 15 epochs.
File Summary:
--------------------------------------------------------------------------------
FileName Lrecl Records Explanations
--------------------------------------------------------------------------------
ReadMe 80 . This file
table2.dat 110 1095 The Reference sample
--------------------------------------------------------------------------------
See also:
II/340 : XMM-OM Serendipitous Source Survey Catalogue, XMM-SUSS2.1
(Page+ 2014)
IX/46 : XMM-Newton Serendipitous Source Catalogue 3XMM-DR5
(XMM-SSC, 2016)
IX/50 : XMM-Newton Serendipitous Source Catalogue 3XMM-DR6
(XMM-SSC, 2016)
VII/260 : The SDSS-DR7 quasar catalog (Schneider+, 2010)
VII/279 : SDSS quasar catalog: twelfth data release (Paris+, 2017)
J/ApJS/194/45 : QSO properties from SDSS-DR7 (Shen+, 2011)
J/A+A/593/A55 : MEXSAS catalogue (Vagnetti+, 2016)
J/ApJS/228/9 : Physical parameters of ∼300000 SDSS-DR12 QSOs (Kozlowski, 2017)
Byte-by-byte Description of file: table2.dat
--------------------------------------------------------------------------------
Bytes Format Units Label Explanations
--------------------------------------------------------------------------------
1- 4 I4 --- MEXSAS2 Source number in the MEXSAS2 catalogue
7- 25 A19 --- Name SDSS source name (JHHMMSS.ss+DDMMSS.s)
27- 34 F8.4 deg RAdeg Right ascension of the SDSS
identification (J2000)
36- 42 F7.4 deg DEdeg Declination of the SDSS
identification (J2000)
44- 48 F5.3 --- z Redshift
50- 54 F5.2 [Msun] logMBH ? log black hole mass
56- 60 F5.2 [10-7W] logLbol ? log bolometric luminosity
62- 66 F5.2 --- logL/LEdd ? log Eddington ratio
68- 69 I2 --- Nepo Number of observing epochs
71- 77 F7.1 d Time Time of observation (MJD)
79- 83 F5.2 [10-7W/Hz] logLUV log monochromatic luminosity at 2500Å
85- 88 F4.2 [10-7W/Hz] e_logLUV Error log monochromatic luminosity
at 2500Å
90- 94 F5.2 [10-7W/Hz] logLX log monochromatic luminosity at 2keV
96- 99 F4.2 [10-7W/Hz] e_logLX Error log monochromatic luminosity at 2keV
101-105 F5.2 --- aox X-ray-to-optical index
107-110 F4.2 --- e_aox Error X-ray-to-optical index
--------------------------------------------------------------------------------
Acknowledgements:
Elia Chiaraluce, elia.chiaraluce (at) inaf.it
(End) Elia Chiaraluce [INAF-IAPS, Roma, Italy] Patricia Vannier [CS] 05-Nov-2018