NuSTAR View of TeV Blazar Mrk 501
Abstract
"We report the results of flux and spectral variability studies of all seven <i>Nuclear Spectroscopic Telescope Array (NuSTAR)</i> observations of TeV <inlineformula><math display=""inline""><semantics><mrow><mi>γ</mi><mo></mo></mrow></semantics></math></inlineformula>ray emitting blazar Markarian (or Mrk) 501. We found strong evidence of intraday variability in 379 keV Xray light curves (LCs) of Mrk 501 during four out of these seven observations. We examined spectral variability using a modelindependent hardnessratio analysis and found a general “harderwhenbrighter” behaviour in two observations. We also investigated the nature of 379 keV Xray spectra of TeV blazar Mrk 501 and found that five out of seven spectra are well described by the curved logparabola models with photon indices (at 10 keV) <inlineformula><math display=""inline""><semantics><mrow><mi>α</mi><mo>∼</mo></mrow></semantics></math></inlineformula> 2.122.32 and a curvature <inlineformula><math display=""inline""><semantics><mrow><mi>β</mi><mo>∼</mo></mrow></semantics></math></inlineformula> 0.150.28. The two other spectra are somewhat better represented by simple powerlaw models with photon indices 2.70 and 2.75. We briefly discuss available physical models to explain our results."
 Publication:

Galaxies
 Pub Date:
 July 2020
 DOI:
 10.3390/galaxies8030055
 arXiv:
 arXiv:2007.14600
 Bibcode:
 2020Galax...8...55P
 Keywords:

 Astrophysics  High Energy Astrophysical Phenomena
 EPrint:
 13 pages, 3 figures, 3 tables, published in special issue "XRay Flux and Spectral Variability of Blazars" of Galaxies journal