X-Ray Spectral Variability of 13 TeV High-energy-peaked Blazars with XMM-Newton

We present a comprehensive study of the X-ray spectral variability observed in 13 TeV photon-emitting high-energy-peaked BL Lacertae objects (HBLs). These data come from 54 XMM-Newton EPIC-pn pointed observations made during its operational period from 2001 June through 2023 July. We performed spect...

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Main Authors: P. U. Devanand, Alok C. Gupta, V. Jithesh, Paul J. Wiita, Archana Gupta
Format: Article
Language:English
Published: IOP Publishing 2025-01-01
Series:The Astrophysical Journal Supplement Series
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Online Access:https://doi.org/10.3847/1538-4365/adc10d
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author P. U. Devanand
Alok C. Gupta
V. Jithesh
Paul J. Wiita
Archana Gupta
author_facet P. U. Devanand
Alok C. Gupta
V. Jithesh
Paul J. Wiita
Archana Gupta
author_sort P. U. Devanand
collection DOAJ
description We present a comprehensive study of the X-ray spectral variability observed in 13 TeV photon-emitting high-energy-peaked BL Lacertae objects (HBLs). These data come from 54 XMM-Newton EPIC-pn pointed observations made during its operational period from 2001 June through 2023 July. We performed spectral studies in the energy range of 0.6–10 keV by fitting X-ray spectra of the pointed observations with power-law and log-parabolic (PL and LP) models. We found at a 99% confidence level that 31 of these X-ray spectra were best fitted with a range of LP models with local photon indices (at 1.0 keV), α  ≃ 1.75–2.66, and convex curvature parameter β  ≃ 0.02–0.25. PL models with photon index Γ ≃ 1.78–2.68 best described the spectra of 14-pointed observations. Nine PN spectra resulted in negative curvature parameters in fitting an LP model, and eight among them were significant ( β ≥ 2 β _err ). We fitted broken power-law models to these eight X-ray spectra and found spectral hardening in the range of ΔΓ ≃ 0.06−0.54 for these observations. EPIC-MOS spectra were also studied for those eight observations to search for similar trends, and we were able to find them in only two, one observation each of PKS 0548-322 and Mrk 501. This indicates the possibility of the coexistence of an inverse Compton component along with the dominant synchrotron component for these two observations. We also performed correlation studies between various LP spectral parameters and briefly discuss their possible implications.
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spelling doaj-art-40f581af076b4d288accedb36f2d77bf2025-08-20T03:53:38ZengIOP PublishingThe Astrophysical Journal Supplement Series0067-00492025-01-0127812010.3847/1538-4365/adc10dX-Ray Spectral Variability of 13 TeV High-energy-peaked Blazars with XMM-NewtonP. U. Devanand0https://orcid.org/0000-0003-3337-4861Alok C. Gupta1https://orcid.org/0000-0002-9331-4388V. Jithesh2https://orcid.org/0000-0002-6449-9643Paul J. Wiita3https://orcid.org/0000-0002-1029-3746Archana Gupta4Aryabhatta Research Institute of Observational Sciences (ARIES) , Manora Peak, Nainital 263001, India; Department of Applied Physics/Physics, Mahatma Jyotiba Phule Rohilkhand University , Bareilly 243006, IndiaAryabhatta Research Institute of Observational Sciences (ARIES) , Manora Peak, Nainital 263001, IndiaDepartment of Physics and Electronics, Christ University , Hosur Main Road, Bengaluru 560029, IndiaDepartment of Physics, The College of New Jersey , 2000 Pennington Road, Ewing, NJ 08628-0718, USADepartment of Applied Physics/Physics, Mahatma Jyotiba Phule Rohilkhand University , Bareilly 243006, IndiaWe present a comprehensive study of the X-ray spectral variability observed in 13 TeV photon-emitting high-energy-peaked BL Lacertae objects (HBLs). These data come from 54 XMM-Newton EPIC-pn pointed observations made during its operational period from 2001 June through 2023 July. We performed spectral studies in the energy range of 0.6–10 keV by fitting X-ray spectra of the pointed observations with power-law and log-parabolic (PL and LP) models. We found at a 99% confidence level that 31 of these X-ray spectra were best fitted with a range of LP models with local photon indices (at 1.0 keV), α  ≃ 1.75–2.66, and convex curvature parameter β  ≃ 0.02–0.25. PL models with photon index Γ ≃ 1.78–2.68 best described the spectra of 14-pointed observations. Nine PN spectra resulted in negative curvature parameters in fitting an LP model, and eight among them were significant ( β ≥ 2 β _err ). We fitted broken power-law models to these eight X-ray spectra and found spectral hardening in the range of ΔΓ ≃ 0.06−0.54 for these observations. EPIC-MOS spectra were also studied for those eight observations to search for similar trends, and we were able to find them in only two, one observation each of PKS 0548-322 and Mrk 501. This indicates the possibility of the coexistence of an inverse Compton component along with the dominant synchrotron component for these two observations. We also performed correlation studies between various LP spectral parameters and briefly discuss their possible implications.https://doi.org/10.3847/1538-4365/adc10dBlazarsBL Lacertae objectsX-ray active galactic nuclei
spellingShingle P. U. Devanand
Alok C. Gupta
V. Jithesh
Paul J. Wiita
Archana Gupta
X-Ray Spectral Variability of 13 TeV High-energy-peaked Blazars with XMM-Newton
The Astrophysical Journal Supplement Series
Blazars
BL Lacertae objects
X-ray active galactic nuclei
title X-Ray Spectral Variability of 13 TeV High-energy-peaked Blazars with XMM-Newton
title_full X-Ray Spectral Variability of 13 TeV High-energy-peaked Blazars with XMM-Newton
title_fullStr X-Ray Spectral Variability of 13 TeV High-energy-peaked Blazars with XMM-Newton
title_full_unstemmed X-Ray Spectral Variability of 13 TeV High-energy-peaked Blazars with XMM-Newton
title_short X-Ray Spectral Variability of 13 TeV High-energy-peaked Blazars with XMM-Newton
title_sort x ray spectral variability of 13 tev high energy peaked blazars with xmm newton
topic Blazars
BL Lacertae objects
X-ray active galactic nuclei
url https://doi.org/10.3847/1538-4365/adc10d
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