X-ray Flux and Spectral Variability of Blazar H 2356-309

Wani, Kiran A.; Gaur, Haritma

doi:10.3390/galaxies8030059

Cited by 3 publications

(2 citation statements)

References 48 publications

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“…Among the 55 HBLs in TeVcat, 19 have been observed by XMM-Newton from its launch until 2022 March. Of these, we excluded four of the sources previously studied by members of the group (e.g Mrk 421; Priyana Noel et al 2022, PKS 2155Bhagwan et al 2014Bhagwan et al , 2016Wani & Gaur 2020;and PG 1533+113;Dhiman et al 2021). We also did not analyze the shorter observations with exposure time less than 10 ks and those longer observations which were affected heavily by background flaring such that the good exposure time was below 10 ks.…”

Section: Data Selection Criteriamentioning

confidence: 99%

“…Variations in flux on timescales from days to a few weeks to even a few months are termed short-term variability (STV), while flux variations seen over greater timespans are termed long-term variability (e.g., Gupta et al 2004). In recent years, we have studied the IDV of blazars in X-ray bands by utilizing timing data from various X-ray telescopes: Chandra (Aggrawal et al 2018), NuSTAR (Pandey et al 2017(Pandey et al , 2018, Suzaku (Zhang et al 2019(Zhang et al , 2021, and XMM-Newton (Gaur et al 2010;Kalita et al 2015;Bhagwan et al 2016;Gupta et al 2016;Wani & Gaur 2020;Dhiman et al 2021).…”

Section: Introductionmentioning

confidence: 99%

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Study of X-Ray Intraday Variability of HBL Blazars Based on Observations Obtained with XMM-Newton

Gupta

Jithesh

et al. 2022

ApJ

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We present an extensive study on the X-ray intraday variability of 10 teraelectronvolt-emitting high synchrotron peaked blazars (HBLs): 1ES 0229+200, 1ES 0414+009, PKS 0548-322, 1ES 1101-232, 1H 1219+301, H 1426+428, Mrk 501, 1ES 1959+650, PKS 2005-489, and 1ES 2344+514 made with 25 XMM-Newton pointed observations during its operational period. Intraday variability has been estimated in three energy bands: soft (0.3–2 keV), hard (2–10 keV), and total (0.3–10 keV). Although seven out of 10 teraelectronvolt HBLs exhibited some intraday variability at 3σ levels, no major variations exceeding 6% were detected. We explored the spectral properties of the sample by extracting the hardness ratio from the soft and hard bands; no significant variations in the hardness ratio were observed in any source. We performed power spectral density analyses on the variable light curves by fitting power laws, yielding slopes lying in the range of 1.11–2.93 for different HBLs. We briefly discuss possible emission mechanisms and carry out rough estimates for magnetic fields, electron Lorentz factors, and emission region sizes for seven of these HBLs.

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Section: Data Selection Criteriamentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Study of X-Ray Intraday Variability of HBL Blazars Based on Observations Obtained with XMM-Newton

Gupta

Jithesh

et al. 2022

ApJ

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Analysis of Bright Source Hardness Ratios in the 4 yr Insight-HXMT Galactic Plane Scanning Survey Catalog

Wang,

Liao,

Guan

et al. 2024

Res. Astron. Astrophys.

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We conduct a statistical analysis of the hardness ratio (HR) for bright sources in the 4 yr Galactic Plane Scanning Survey (GPSS) catalog of Insight-HXMT. Depending on the stable (variable) flux F s (F v) or spectrum S s (S v) of each source, the bright sources are classified into three groups: F v&S v, F v&S s, and F s&S s. Our study of the HR characteristics in different types of sources reveals that accretion-powered neutron star (NS) low-mass X-ray binaries (LMXBs) exhibit softer energy spectra than NS high-mass X-ray binaries (HMXBs), but harder energy spectra than black hole (BH) binaries in most cases. This difference is probably due to their different magnetic field strengths. Additionally, F v&S v LMXBs tend to be harder than F v&S s LMXBs below 7 keV, while the opposite is true for HMXBs. Our results suggest that LMXBs may dominate unclassified sources, and NS binaries are likely to be the primary type of X-ray binaries with ambiguous compact stars. By comparing the HR of transient sources in their outburst and low-flux states, it is found that the averaged HR of four sources in the two states are roughly comparable within uncertainties. We also investigate the spatial properties of the three groups and find that F v&S v sources are mainly located in the longitude of $-20^\circ<l<9^\circ$, F v&S s sources cross the Galactic Plane, and F s&S s sources are predominantly concentrated in 19°<l<42°. In addition, analyzing the HR spatial distributions shows the absorption of soft X-rays (primarily below 2 keV) in the Galactic Plane.

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X-ray timing and spectral variability properties of blazars S5 0716 + 714, OJ 287, Mrk 501, and RBS 2070

Mohorian

Bhatta

Adhikari

et al. 2021

Monthly Notices of the Royal Astronomical Society

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The X-ray emission from blazars has been widely investigated using several space telescopes. In this work, we explored statistical properties of the X-ray variability in the blazars S5 0716+714, OJ 287, Mkn 501 and RBS 2070 using the archival observations from the XMM-Newton telescope between the period 2002–2020. Several methods of timing and spectral analyses including fractional variability, minimum variability timescale, power spectral density analyses and countrate distribution were performed. In addition, we fitted various spectral models to the observations as well as estimated hardness ratio. The results show that the sources are moderately variable within the intra-day timescale. Three of the four sources exhibited a clear bi-modal pattern in their countrate distribution revealing possible indication of two distinct countrate states, that is, hard and soft countrate states. The slope indices of the power spectral density were found to be centered around 0.5. Furthermore, the spectra of the sources were fitted with single power-law, broken power-law, log-parabolic and black-body+log-parabolic models (the latter only for OJ 287). We conclude that for most of the observations log-parabolic model was the best fit. The power spectral density analysis revealed the variable nature of PSD slopes in the source light curves. The results of this analysis could indicate the non-stationary nature of the blazar processes on intra-day timescales. The observed features can be explained within the context of current blazar models, in which the non-thermal emission mostly arises from kilo-parsec scale relativistic jets.

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X-ray Flux and Spectral Variability of Blazar H 2356-309

Cited by 3 publications

References 48 publications

Study of X-Ray Intraday Variability of HBL Blazars Based on Observations Obtained with XMM-Newton

Study of X-Ray Intraday Variability of HBL Blazars Based on Observations Obtained with XMM-Newton

Analysis of Bright Source Hardness Ratios in the 4 yr Insight-HXMT Galactic Plane Scanning Survey Catalog

X-ray timing and spectral variability properties of blazars S5 0716 + 714, OJ 287, Mrk 501, and RBS 2070

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