X-ray flux variability of active galactic nuclei observed using NuSTAR

Abstract

We present results on a systematic study of flux variability on hourly time-scales in a large sample of active galactic nuclei (AGN) in the 3-79 keV band using data from Nuclear Spectroscopic Telescope Array. Our sample consists of 4 BL Lac objects (BL Lacs), 3 flat spectrum radio quasars (FSRQs) 24 Seyfert 1, 42 Seyfert 2 and 8 narrow line Seyfert 1 (NLSy1) galaxies. We find that in the 3-79 keV band, about 65% of the sources in our sample show significant variations on hourly time scales. Using Mann-Whitney U-test and 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 (3-10 keV), hard (10-79 keV) and total (3-79 keV) bands. NLSy1 galaxies show the highest duty cycle of variability (87%), followed by BL Lacs (82%), Seyfert galaxies (56%) and FSRQs (23%). 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.

15 pages, 7 figures, 10 tables, accepted for publication in MNRAS

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Cited by in corpus (13)

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• Numerical Analysis of Long-term Variability of AGN Jets through RMHD Simulations
• Study of correlation between optical flux and polarization variations in BL Lac objects
• Mid-infrared Variability of gamma-ray emitting blazars
• Estimation of the size and structure of the broad line region using Bayesian approach
• Dust Reverberation Mapping of Z229-15
• NuSTAR observations of the unidentified INTEGRAL sources: constraints on the Galactic population of HMXBs
• Changing look AGN Mrk 590: Broad line region and black hole mass from photometric reverberation mapping
• The blazar sequence revised