J/MNRAS/466/3309 X-ray flux variability of AGN (Rani+, 2017)
X-ray flux variability of active galactic nuclei observed using NuSTAR.
Rani P., Stalin C.S., Rakshit S.
<Mon. Not. R. Astron. Soc., 466, 3309-3322 (2017)>
=2017MNRAS.466.3309R 2017MNRAS.466.3309R (SIMBAD/NED BibCode)
ADC_Keywords: Active gal. nuclei ; X-ray sources
Keywords: galaxies: active - BL Lacertae objects: general - galaxies: jets -
galaxies: nuclei - galaxies: Seyfert - X-rays: galaxies
Abstract:
We present results of a systematic study of flux variability on hourly
time-scales in a large sample of active galactic nuclei (AGN) in the
3-79keV band using data from Nuclear Spectroscopic Telescope Array.
Our sample consists of four BL Lac objects (BL Lacs), three flat
spectrum radio quasars (FSRQs) 24 Seyfert 1, 42 Seyfert 2 and eight
narrow line Seyfert 1 (NLSy1) galaxies. We find that in the 3-79keV
band, about 65 per cent of the sources in our sample show significant
variations on hourly time-scales. Using the Mann-Whitney U-test and
the Kolmogorov-Smirnov test, we find no difference in the variability
behaviour between Seyfert 1 and 2 galaxies. The blazar sources (FSRQs
and BL Lacs) in our sample are more variable than Seyfert galaxies
that include Seyfert 1 and Seyfert 2 in the soft (3-10keV), hard
(10-79keV) and total (3-79keV) bands. NLSy1 galaxies show the
highest duty cycle of variability (87 per cent), followed by BL Lacs
(82 per cent), Seyfert galaxies (56 per cent) and FSRQs (23 per cent).
We obtained flux doubling/halving time in the hard X-ray band less
than 10 min in 11 sources. The flux variations between the hard and
soft bands in all the sources in our sample are consistent with zero
lag.
Description:
The goal of this work is to find the hard X-ray flux variations in
different types of AGN. For this we have used the data from NuSTAR.
NuSTAR, launched in 2012 June, is the first focusing hard X-ray
telescope. It has a field of view 13x13-arcmin2. It consists of two
co-aligned X-ray detector pairs with corresponding focal plane modules
FPMA and FPMB.1NuSTAR observations of all AGN that have become public
before 2015 March have been used in this work. Our sample thus
consists of 81 AGN, among these four are BL Lacs, three are FSRQs, 24
are Seyfert 1 galaxies, 42 are Seyfert 2 galaxies and eight are narrow
line Seyfert 1 (NLSy1) galaxies. The details of the sources used in
this study are given in Table 1.
File Summary:
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FileName Lrecl Records Explanations
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ReadMe 80 . This file
table1.dat 63 81 Information on the sources studied for
flux variability
table2.dat 95 30 Characteristics of flux variations of
BL Lac objects
table3.dat 95 7 Characteristics of flux variations of FSRQs
table4.dat 95 28 Characteristics of flux variations of
Seyfert 1 galaxies
table5.dat 95 36 Characteristics of flux variations of
Seyfert 2 galaxies
table6.dat 95 14 Characteristics of flux variations of
NLSy1 galaxies
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Byte-by-byte Description of file: table1.dat
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Bytes Format Units Label Explanations
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1- 20 A20 --- Name Name
22- 23 I2 h RAh Right ascension (J2000)
25- 26 I2 min RAm Right ascension (J2000)
28- 31 F4.1 s RAs Right ascension (J2000)
33 A1 --- DE- Declination sign (J2000)
34- 35 I2 deg DEd Declination (J2000)
37- 38 I2 arcmin DEm Declination (J2000)
40- 41 I2 arcsec DEs Declination (J2000)
43 A1 --- n_Vmag [*] Note on Vmag (1)
44- 48 F5.2 mag Vmag ? V magnitude
50- 54 F5.3 --- z Redshift
56- 63 A8 --- Type Type
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Note (1): The quoted magnitudes are the V-band magnitudes taken from
Veron-Cetty & Veron (2010A&A...518A..10V 2010A&A...518A..10V, Cat. VII/258) except for those
appended with a asterisk (*) for which it is from NED
(http://ned.ipac.caltech.edu/).
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Byte-by-byte Description of file: table[23456].dat
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Bytes Format Units Label Explanations
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1- 20 A20 --- Name Name
22- 29 A8 --- Type Type
31- 41 I11 --- ObsID Observation ID
43- 52 A10 "date" Obs.date Observation date
54- 59 I6 s Texp Exposure time
61- 65 F5.3 --- FvarS Flux variation in soft band, 3-10keV
67- 71 F5.3 --- e_FvarS rms uncertainty on FvarS
73- 77 F5.3 --- FvarH Flux variation in hard band, 10-79keV
79- 83 F5.3 --- e_FvarH rms uncertainty on FvarH
85- 89 F5.3 --- FvarT Flux variation in total band, 3-79keV
91- 95 F5.3 --- e_FvarT rms uncertainty on FvarT
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History:
From electronic version of the journal
(End) Patricia Vannier [CDS] 13-Nov-2019