@article{4b67e9f8cf51420c87cc6b0f9988bcab,
title = "X-ray spectra, light curves and SEDs of blazars frequently observed by Swift",
abstract = "Blazars research is one of the hot topics of contemporary extragalactic astrophysics. That is because these sources are the most abundant type of extragalactic γ-ray sources and are suspected to play a central role in multimessenger astrophysics. We have used Swift xrtproc, a tool to carry out an accurate spectral and photometric analysis of the Swift-XRT data of all blazars observed by Swift at least 50 times between December 2004 and the end of 2020. We present a database of X-ray spectra, best-fit parameter values, count rates and flux estimations in several energy bands of over 31 000 X-ray observations and single snapshots of 65 blazars. The results of the X-ray analysis have been combined with other multifrequency archival data to assemble the broad-band Spectral Energy Distributions (SEDs) and the long-term light curves of all sources in the sample. Our study shows that large X-ray luminosity variability on different time-scales is present in all objects. Spectral changes are also frequently observed with a {\textquoteleft}harder-when-brighter{\textquoteright} or {\textquoteleft}softer-when-brighter{\textquoteright} behaviour depending on the SED type of the blazars. The peak energy of the synchrotron component (νpeak) in the SED of HBL blazars, estimated from the log-parabolic shape of their X-ray spectra, also exhibits very large changes in the same source, spanning a range of over two orders of magnitude in Mrk421 and Mrk501, the objects with the best data sets in our sample.",
keywords = "Astronomical data bases: catalogues, Galaxies: BL Lacertae objects, Galaxies: active, Methods: data analysis, Quasars: general, X-rays: galaxies",
author = "Paolo Giommi and M. Perri and M. Capalbi and V. D{\textquoteright}Elia and {Barres de Almeida}, U. and Brandt, {C. H.} and Pollock, {A. M.T.} and F. Arneodo and {Di Giovanni}, A. and Chang, {Y. L.} and O. Civitarese and {de Angelis}, M. and C. Leto and F. Verrecchia and N. Ricard and {Di Pippo}, S. and R. Middei and Penacchioni, {A. V.} and R. Ruffini and N. Sahakyan and D. Israyelyan and S. Turriziani",
note = "Funding Information: PG acknowledges the support of the Technische Universit{\"a}t M{\"u}nchen – Institute for Advanced Studies, funded by the German Excellence Initiative (and the European Union Seventh Framework Programme under grant agreement number 291763) and the support by the Excellence Cluster ORIGINS, which is funded by the Deutsche Forschungsgemeinschaft (DFG, German Research Foundation) under Germany{\textquoteright}s Excellence Strategy – EXEC-2094 - 390783311. CHB acknowledges the support of ICRANet and the Brazilian government, funded by the CAPES Foundation, Ministry of Education of Brazil under the project BEX 15113-13-2. UBdA acknowledges the support of a CNPq Productivity Research grant number 311997/2019-8 and a Serrapilheira Institute grant number Serra – 1812-26906. He also acknowledges the receipt of a FAPERJ Young Scientist Fellowship number E-26/202.818/2019. RM acknowledges the financial support of INAF (Istituto Nazionale di Astrofisica), Osservatorio Astronomico di Roma, ASI (Agenzia Spaziale Italiana) under contract to INAF: ASI 2014-049-R.0 dedicated to SSDC. NS acknowledges the support by the Science Committee of RA, in the frames of the research project number 20TTCG-1C015. Publisher Copyright: {\textcopyright} 2021 The Author(s).",
year = "2021",
month = nov,
day = "1",
doi = "10.1093/mnras/stab2425",
language = "English (US)",
volume = "507",
pages = "5690--5702",
journal = "Monthly Notices of the Royal Astronomical Society",
issn = "0035-8711",
publisher = "Oxford University Press",
number = "4",
}