J/ApJ/801/45 Quasars properties and reverberation mapping (Hernitschek+, 2015)
Estimating black hole masses in hundreds of quasars.
Hernitschek N., Rix H.-W., Bovy J., Morganson E.
<Astrophys. J., 801, 45 (2015)>
=2015ApJ...801...45H 2015ApJ...801...45H (SIMBAD/NED BibCode)
ADC_Keywords: QSOs ; Active gal. nuclei ; Galaxies, photometry ; Redshifts ;
Equivalent widths
Keywords: galaxies: photometry - quasars: supermassive black holes
Abstract:
We explore the practical feasibility of active galactic nucleus (AGN)
broadband reverberation mapping and present first results. We lay out
and apply a rigorous approach for the stochastic reverberation mapping
of unevenly sampled multi-broadband flux measurements, assuming that
the broad-line region (BLR) line flux is contributing up to 15% in
some bands, and is directly constrained by one spectroscopical epoch.
The approach describes variations of the observed flux as the
continuum, modeled as a stochastic Gaussian process, and emission line
contribution, modeled as a scaled, smoothed, and delayed version of
the continuum. This approach can be used not only to interpolate in
time between measurements, but also to determine confidence limits on
continuum-line emission delays. This approach is applied to Sloan
Digital Sky Survey observations in Stripe 82 (S82), providing flux
measurements that are precise to 2% at ∼60 epochs over ∼10 yr. The
strong annual variations in the epoch sampling prove a serious
limitation in practice. In addition, suitable redshift ranges must be
identified where strong, broad emission lines contribute to one
filter, but not to another. By generating and evaluating
problem-specific mock data, we verify that S82-like data can constrain
τdelay for a simple transfer function model. In application to
real data, we estimate τdelay for 323 AGNs with 0.225<z<0.846,
combining information for different objects through the ensemble-scaling
relationships for BLR size and black hole mass. Our analysis
tentatively indicates a 1.7 times larger BLR size of Hα and Mg II
compared to Kaspi et al. (2000ApJ...533..631K 2000ApJ...533..631K; 2007ApJ...659..997K 2007ApJ...659..997K) and
Vestergaard (2002ApJ...571..733V 2002ApJ...571..733V; 2006ApJ...641..689V 2006ApJ...641..689V), but the
seasonal data sampling casts doubt on the robustness of the inference.
Description:
We present novel empirical relationships for estimating the BLR sizes
in AGNs developed using multi-epoch photometry combined with
single-epoch spectroscopy. The found that scaling relationships
between line widths and luminosity are based on empirical
relationships between the broad-line region (BLR) size and
luminosities in various bands by Kaspi et al. (2000ApJ...533..631K 2000ApJ...533..631K),
Bentz et al. (2013ApJ...767..149B 2013ApJ...767..149B), and Vestergaard (2002ApJ...571..733V 2002ApJ...571..733V).
To obtain more definite results on the RBLR-L and MBH-L relations, we
evaluate well-defined subsamples of reverberation-mapped AGN, as shown
in the Tables 2-5.
File Summary:
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FileName Lrecl Records Explanations
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ReadMe 80 . This file
table2.dat 124 29 Sample 1 Properties and Reverberation Mapping
Results z=0.225-0.291, with i Band: Hα,
z Band: Continuum
table3.dat 124 68 Sample 2 Properties and Reverberation Mapping
Results z=0.555-0.591, with g Band: Mg II,
r Band: Continuum
table4.dat 124 111 Sample 3 Properties and Reverberation Mapping
Results z=0.592-0.6999, with g Band: Mg II,
r Band: Continuum
table5.dat 124 115 Sample 4 Properties and Reverberation Mapping
Results z=0.7-0.846, with g Band: Mg II,
r Band: Continuum
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See also:
VII/69 : Asiago Catalogue of QSOs (Barbieri+ 1983)
J/ApJ/613/682 : AGN central masses and broad-line region sizes
(Peterson+, 2004)
J/ApJ/669/791 : Quasar black hole masses (Wilhite+, 2007)
J/A+A/525/A37 : Variability indexes of QSOs in SDSS Stripe 82
(Meusinger+, 2011)
J/ApJ/805/96 : SDSS-RM project: velocity dispersions of QSOs (Shen+, 2015)
Byte-by-byte Description of file: table2.dat table3.dat table4.dat table5.dat
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Bytes Format Units Label Explanations
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1- 18 I18 --- ID objid SDSS unique object identifier
20- 25 F6.4 --- z Redshift
27- 34 E8.3 0.1nm EW Rest frame equivalent width of broad line
36- 41 E6.3 0.1nm e_EW Uncertainty in EW
43- 52 E10.6 10+3km/s FWHM(Hb) ? FWHM of broad Hβ line
54- 59 E6.2 10+3km/s e_FWHM(Hb) ? Uncertainty in FWHM(Hb)
61- 67 F7.4 [10-7W] logL5100 Log luminosity at 5100Å (erg/s)
69- 74 F6.4 [10-7W] e_logL5100 Uncertainty in logL5100
76- 83 E8.5 173AU RBLRk BLR (broad-line region) size, computed from
Kaspi relation (2000ApJ...533..631K 2000ApJ...533..631K), in
rest frame, in light-days units
85- 90 E6.3 173AU E_RBLRk ? Upper limit uncertainty in RBLRk
92- 97 E6.3 173AU e_RBLRk ? Lower limit uncertainty in RBLRk
99-106 E8.4 173AU RBLR BLR size own computed from all points
within the 68% confidence interval, in
rest frame, in light-days units
108-115 E8.4 173AU E_RBLR Upper limit uncertainty in RBLR
117-124 E8.4 173AU e_RBLR Lower limit uncertainty in RBLR
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History:
From electronic version of the journal
(End) Prepared by Tiphaine Pouvreau [CDS] 25-Aug-2017