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Article: Observation of X-ray variability in the BL Lacertae object 1ES 1959+65

TitleObservation of X-ray variability in the BL Lacertae object 1ES 1959+65
Authors
KeywordsBl Lacertae Objects: Individual (1Es 1959+65)
X-Rays: Galaxies
Issue Date2002
PublisherInstitute of Physics Publishing Ltd. The Journal's web site is located at http://iopscience.iop.org/2041-8205
Citation
Astrophysical Journal Letters, 2002, v. 571 n. 2 I, p. 763-770 How to Cite?
AbstractThis paper reports X-ray spectral observations of a relatively nearby (z = 0.048) BL Lac object 1ES 1959+65, which is a potential TeV emitter. The observations include 31 short pointings made by the Unconventional Stellar Aspect (USA) experiment on board the Advanced Research and Global Observation Satellite (ARGOS), and 17 pointings by the Proportional Counter Array (PCA) on board the Rossi X-Ray Timing Explorer (RXTE). Most of these observations were spaced by less than 1 day. 1ES 1959+65 was detected by the ARGOS USA detector in the range 1-16 keV, and by the PCA in the 2-16 keV range but at different times. During the closely spaced RXTE observations beginning on 2000 July 28, the ending of one flare and the start of another are visible, associated with spectral changes, where the photon index Γ ranges between ∼ 1.4 and ∼ 1.7, and the spectrum is harder when the source is brighter. This implies that 1ES 1959+65 is an X-ray-selected BL Lac type (XBL) blazar, with the X-ray emission likely to originate via the synchrotron process. The USA observations reveal another flare that peaked on 2000 November 14 and doubled the flux within a few days, again associated with spectral changes of the same form. The spectral variability correlated with the flux and timing characteristics of this object that are similar to those of other nearby BL Lac objects and suggest relativistic beaming with a Doppler factor δ ≥ 1.6 and magnetic fields on the order of a few milligauss. We also suggest that the steady component of the X-ray emission - present in this object as well as in other XBLs - may be due to the large-scale relativistic jet (such as measured by Chandra in many radio-loud active galactic nuclei) but pointing very closely to our line of sight.
Persistent Identifierhttp://hdl.handle.net/10722/188350
ISSN
2023 Impact Factor: 8.8
2023 SCImago Journal Rankings: 2.766
ISI Accession Number ID
References

 

DC FieldValueLanguage
dc.contributor.authorGiebels, Ben_US
dc.contributor.authorBloom, EDen_US
dc.contributor.authorFocke, Wen_US
dc.contributor.authorGodfrey, Gen_US
dc.contributor.authorMadejski, Gen_US
dc.contributor.authorReilly, KTen_US
dc.contributor.authorSaz Parkinson, PMen_US
dc.contributor.authorShabad, Gen_US
dc.contributor.authorBandyopadhyay, RMen_US
dc.contributor.authorFritz, GGen_US
dc.contributor.authorHertz, Pen_US
dc.contributor.authorKowalski, MPen_US
dc.contributor.authorLovellette, MNen_US
dc.contributor.authorRay, PSen_US
dc.contributor.authorWolff, MTen_US
dc.contributor.authorWood, KSen_US
dc.contributor.authorYentis, DJen_US
dc.contributor.authorScargle, JDen_US
dc.date.accessioned2013-09-03T04:03:32Z-
dc.date.available2013-09-03T04:03:32Z-
dc.date.issued2002en_US
dc.identifier.citationAstrophysical Journal Letters, 2002, v. 571 n. 2 I, p. 763-770en_US
dc.identifier.issn2041-8205en_US
dc.identifier.urihttp://hdl.handle.net/10722/188350-
dc.description.abstractThis paper reports X-ray spectral observations of a relatively nearby (z = 0.048) BL Lac object 1ES 1959+65, which is a potential TeV emitter. The observations include 31 short pointings made by the Unconventional Stellar Aspect (USA) experiment on board the Advanced Research and Global Observation Satellite (ARGOS), and 17 pointings by the Proportional Counter Array (PCA) on board the Rossi X-Ray Timing Explorer (RXTE). Most of these observations were spaced by less than 1 day. 1ES 1959+65 was detected by the ARGOS USA detector in the range 1-16 keV, and by the PCA in the 2-16 keV range but at different times. During the closely spaced RXTE observations beginning on 2000 July 28, the ending of one flare and the start of another are visible, associated with spectral changes, where the photon index Γ ranges between ∼ 1.4 and ∼ 1.7, and the spectrum is harder when the source is brighter. This implies that 1ES 1959+65 is an X-ray-selected BL Lac type (XBL) blazar, with the X-ray emission likely to originate via the synchrotron process. The USA observations reveal another flare that peaked on 2000 November 14 and doubled the flux within a few days, again associated with spectral changes of the same form. The spectral variability correlated with the flux and timing characteristics of this object that are similar to those of other nearby BL Lac objects and suggest relativistic beaming with a Doppler factor δ ≥ 1.6 and magnetic fields on the order of a few milligauss. We also suggest that the steady component of the X-ray emission - present in this object as well as in other XBLs - may be due to the large-scale relativistic jet (such as measured by Chandra in many radio-loud active galactic nuclei) but pointing very closely to our line of sight.en_US
dc.languageengen_US
dc.publisherInstitute of Physics Publishing Ltd. The Journal's web site is located at http://iopscience.iop.org/2041-8205en_US
dc.relation.ispartofAstrophysical Journal Lettersen_US
dc.subjectBl Lacertae Objects: Individual (1Es 1959+65)en_US
dc.subjectX-Rays: Galaxiesen_US
dc.titleObservation of X-ray variability in the BL Lacertae object 1ES 1959+65en_US
dc.typeArticleen_US
dc.identifier.emailSaz Parkinson, PM: pablosp@hku.hken_US
dc.identifier.authoritySaz Parkinson, PM=rp01803en_US
dc.description.naturelink_to_subscribed_fulltexten_US
dc.identifier.doi10.1086/340065en_US
dc.identifier.scopuseid_2-s2.0-0010044190en_US
dc.relation.referenceshttp://www.scopus.com/mlt/select.url?eid=2-s2.0-0010044190&selection=ref&src=s&origin=recordpageen_US
dc.identifier.volume571en_US
dc.identifier.issue2 Ien_US
dc.identifier.spage763en_US
dc.identifier.epage770en_US
dc.identifier.isiWOS:000175830800015-
dc.publisher.placeUnited Kingdomen_US
dc.identifier.scopusauthoridGiebels, B=8834452900en_US
dc.identifier.scopusauthoridBloom, ED=7102733236en_US
dc.identifier.scopusauthoridFocke, W=7003889095en_US
dc.identifier.scopusauthoridGodfrey, G=35228901000en_US
dc.identifier.scopusauthoridMadejski, G=35373279300en_US
dc.identifier.scopusauthoridReilly, KT=10640545300en_US
dc.identifier.scopusauthoridSaz Parkinson, PM=8948464400en_US
dc.identifier.scopusauthoridShabad, G=6603215912en_US
dc.identifier.scopusauthoridBandyopadhyay, RM=7005269280en_US
dc.identifier.scopusauthoridFritz, GG=7102517424en_US
dc.identifier.scopusauthoridHertz, P=7006530585en_US
dc.identifier.scopusauthoridKowalski, MP=7103377351en_US
dc.identifier.scopusauthoridLovellette, MN=6602728724en_US
dc.identifier.scopusauthoridRay, PS=7401892043en_US
dc.identifier.scopusauthoridWolff, MT=7403308674en_US
dc.identifier.scopusauthoridWood, KS=7401835806en_US
dc.identifier.scopusauthoridYentis, DJ=6602273515en_US
dc.identifier.scopusauthoridScargle, JD=6603849454en_US
dc.identifier.issnl2041-8205-

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