J/ApJ/896/122 BAT AGN Spectroscopic Survey. XVIII. Periodic var. (Liu+, 2020)
The BAT AGN Spectroscopic Survey.
XVIII. Searching for supermassive black hole binaries in X-rays.
Liu T., Koss M., Blecha L., Ricci C., Trakhtenbrot B., Mushotzky R.,
Harrison F., Ichikawa K., Kakkad D., Oh K., Powell M., Privon G.C.,
Schawinski K., Shimizu T.T., Smith K.L., Stern D., Treister E., Urry C.M.
<Astrophys. J., 896, 122 (2020)>
=2020ApJ...896..122L 2020ApJ...896..122L
ADC_Keywords: Active gal. nuclei; X-ray sources; Surveys
Keywords: Active galaxies ; Surveys ; X-ray sources
Abstract:
Theory predicts that a supermassive black hole binary (SMBHB) could be
observed as a luminous active galactic nucleus (AGN) that periodically
varies on the order of its orbital timescale. In X-rays, periodic
variations could be caused by mechanisms including relativistic
Doppler boosting and shocks. Here we present the first systematic
search for periodic AGNs using 941 hard X-ray light curves (14-195keV)
from the first 105 months of the Swift Burst Alert Telescope (BAT)
survey (2004-2013). We do not find evidence for periodic AGNs in
Swift-BAT, including the previously reported SMBHB candidate
MCG+11-11-032. We find that the null detection is consistent with the
combination of the upper-limit binary population in AGNs in our
adopted model, their expected periodic variability amplitudes, and the
BAT survey characteristics. We have also investigated the
detectability of SMBHBs against normal AGN X-ray variability in the
context of the extended ROentgen Survey with an Imaging Telescope
Array (eROSITA) survey. Under our assumptions of a binary population
and the periodic signals they produce, which have long periods of
hundreds of days, up to 13% true periodic binaries can be robustly
distinguished from normal variable AGNs with the ideal uniform
sampling. However, we demonstrate that realistic eROSITA sampling is
likely to be insensitive to long-period binaries because longer
observing gaps reduce their detectability. In contrast, large
observing gaps do not diminish the prospect of detecting binaries of
short, few-day periods, as 19% can be successfully recovered, the vast
majority of which can be identified by the first half of the survey.
File Summary:
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FileName Lrecl Records Explanations
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ReadMe 80 . This file
table1.dat 59 941 Variability properties of the BAT AGN sample
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See also:
J/ApJ/633/L77 : SWIFT/BAT detections of AGN (Markwardt+, 2005)
J/ApJ/681/113 : Swift BAT survey of AGNs (Tueller+, 2008)
J/ApJS/186/1 : 4th IBIS/ISGRI soft gamma-ray survey catalog (Bird+, 2010)
J/A+A/523/A61 : INTEGRAL all-sky survey of X-ray sources (Krivonos+, 2010)
J/ApJS/186/378 : Hard X-ray survey from Swift-BAT 2004-2006 (Tueller+, 2010)
J/ApJ/746/L22 : Dual AGNs in the nearby Universe (Koss+, 2012)
J/ApJS/207/19 : Hard X-ray survey from Swift-BAT 6yrs (Baumgartner+, 2013)
J/A+A/563/A57 : Long-term variability of AGN at hard X-rays (Soldi+, 2014)
J/MNRAS/453/1562 : CRTS close supermassive black hole binaries (Graham+, 2015)
J/ApJ/813/82 : z<0.06 broad-line AGN emission-line measures (Reines+, 2015)
J/ApJ/815/L13 : Compton-thick AGNs from 70-month Swift/BAT (Ricci+, 2015)
J/ApJ/850/74 : Swift/BAT AGN Spectroscopic Survey. I. (Koss+, 2017)
J/ApJS/233/17 : Swift/BAT AGN spectroscopic survey. V. X-ray (Ricci+, 2017)
J/ApJS/235/4 : 105-month Swift-BAT all-sky hard X-ray survey (Oh+, 2018)
Byte-by-byte Description of file: table1.dat
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Bytes Format Units Label Explanations
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1- 4 I4 --- Seq [1/1632] Swift-BAT 105-month catalog ID
6- 18 A13 --- SWIFT BAT name of the source (JHHMM+DDMMA or
JHHMM.m+DDMM)
20- 26 F7.3 deg RAdeg BAT right ascension of the source (J2000)
28- 34 F7.3 deg DEdeg BAT declination of the source (J2000)
36- 43 F8.4 10-7 Sigxs2 [0/414.51] Excess variance (1)
45- 45 A1 --- Var? Whether the source is classified as
intrinsically variable ("Y"=220 occurrences)
47- 53 F7.2 % fvar [10/2007.6]? Fractional variability (2)
55- 59 A5 --- Type Whether the intrinsic variability can be
characterized by red noise or white noise
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Note (1): Excess variance σxs2=S2-σerr2.
A negative value is forced to be zero.
Note (2): Fractional variability fvar=(σxs/)*100%
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History:
From electronic version of the journal
References:
Koss et al. Paper I. 2017ApJ...850...74K 2017ApJ...850...74K Cat. J/ApJ/850/74
Berney et al. Paper II. 2015MNRAS.454.3622B 2015MNRAS.454.3622B
Oh et al. Paper III. 2017MNRAS.464.1466O 2017MNRAS.464.1466O
Lamperti et al. Paper IV. 2017MNRAS.467..540L 2017MNRAS.467..540L
Ricci et al. Paper V. 2017ApJS..233...17R 2017ApJS..233...17R Cat. J/ApJS/233/17
Trakhtenbrot et al. Paper VI. 2017MNRAS.470..800T 2017MNRAS.470..800T
Shimizu et al. Paper VIII. 2018ApJ...856..154S 2018ApJ...856..154S
Powell et al. Paper IX. 2018ApJ...858..110P 2018ApJ...858..110P
Ichikawa et al. Paper XI. 2019ApJ...870...31I 2019ApJ...870...31I Cat. J/ApJ/870/31
Ricci et al. Paper XII. 2018MNRAS.480.1819R 2018MNRAS.480.1819R
Bar et al. Paper XIII. 2019MNRAS.489.3073B 2019MNRAS.489.3073B
Smith et al. Paper XV. 2020MNRAS.492.4216S 2020MNRAS.492.4216S
Paliya et al. Paper XVI. 2019ApJ...881..154P 2019ApJ...881..154P Cat. J/ApJ/881/154
Baek et al. Paper XVII. 2019MNRAS.488.4317B 2019MNRAS.488.4317B
Liu et al. Paper XVIII. 2020ApJ...896..122L 2020ApJ...896..122L This catalog
Rojas et al. Paper XIX. 2020MNRAS.491.5867R 2020MNRAS.491.5867R
Koss et al. Paper XX. 2021ApJS..252...29K 2021ApJS..252...29K Cat. J/apJS/252/29
Gupta et al. Paper XXVII. 2021MNRAS.504..428G 2021MNRAS.504..428G
(End) Prepared by [AAS], Emmanuelle Perret [CDS] 29-Oct-2021