J/MNRAS/454/1525ivo://CDS.VizieR/J/MNRAS/454/1525doi:10.26093/cds/vizier.74541525CDSPonti G.De Marco B.Morris M.R.Merloni A.Munoz-Darias T.Clavel M.,Haggard D.Zhang S.Nandra K.Gillessen S.Mori K.Neilsen J.Rea N.,Degenaar N.Terrier R.Goldwurm A.2024-08-15T20:15:45Z2018-01-15T09:37:10ZCDS support team

CDS, Observatoire de Strasbourg, 11 rue de l'Universite, F-67000 Strasbourg, France

cds-question@unistra.frmilky-way-galaxyx-ray-sourcesephemeridesWe present a study of the X-ray flaring activity of Sgr A* during all the 150 XMM-Newton and Chandra observations pointed at the Milky Way centre over the last 15 years. This includes the latest XMM-Newton and Chandra campaigns devoted to monitoring the closest approach of the very red Br{gamma} emitting object called G2. The entire data set analysed extends from 1999 September through 2014 November. We employed a Bayesian block analysis to investigate any possible variations in the characteristics (frequency, energetics, peak intensity, duration) of the flaring events that Sgr A* has exhibited since their discovery in 2001. We observe that the total bright or very bright flare luminosity of Sgr A* increased between 2013 and 2014 by a factor of 2-3 (~3.5{sigma} significance). We also observe an increase (~99.9 percent significance) from 0.27+/-0.04 to 2.5+/-1.0/d of the bright or very bright flaring rate of Sgr A*, starting in late summer 2014, which happens to be about six months after G2's pericentre passage. This might indicate that clustering is a general property of bright flares and that it is associated with a stationary noise process producing flares not uniformly distributed in time (similar to what is observed in other quiescent black holes). If so, the variation in flaring properties would be revealed only now because of the increased monitoring frequency. Alternatively, this may be the first sign of an excess accretion activity induced by the close passage of G2. More observations are necessary to distinguish between these two hypotheses.2015MNRAS.454.1525Phttps://cdsarc.cds.unistra.fr/viz-bin/cat/J/MNRAS/454/1525CatalogResearchIsServedByTAP VizieR generic serviceIsServedByConesearch servicerelated-toB/chandra : The Chandra Archive Log (CXC, 1999-2014)B/xmm : XMM-Newton Observation LogJ/ApJ/589/225 : Chandra X-ray sources toward Galactic Center (Muno+, 2003)J/ApJS/181/110 : Galactic center X-ray sources (Muno+, 2009)https://cds.unistra.fr/vizier-org/licences_vizier.htmlhttps://vizier.cds.unistra.fr/viz-bin/VizieR-2?-source=J/MNRAS/454/1525https://vizier.iucaa.in/viz-bin/VizieR-2?-source=J/MNRAS/454/1525http://vizieridia.saao.ac.za/viz-bin/VizieR-2?-source=J/MNRAS/454/1525https://vizier.cds.unistra.fr/viz-bin/votable?-source=J/MNRAS/454/1525https://vizier.iucaa.in/viz-bin/votable?-source=J/MNRAS/454/1525http://vizieridia.saao.ac.za/viz-bin/votable?-source=J/MNRAS/454/1525GETtext/xml+votablehttps://tapvizier.cds.unistra.fr/TAPVizieR/tapCone search capability for table J/MNRAS/454/1525/Chandra (List of all Chandra observations on Sgr A* performed between 1999 and 2014)https://vizier.cds.unistra.fr/viz-bin/conesearch/J/MNRAS/454/1525/Chandra?https://vizier.iucaa.in/viz-bin/conesearch/J/MNRAS/454/1525/Chandra?http://vizieridia.saao.ac.za/viz-bin/conesearch/J/MNRAS/454/1525/Chandra?GETtext/xml+votable180.050000true266.41667-29.007780.005555555555555556Cone search capability for table J/MNRAS/454/1525/tablea4 (List of all XMM-Newton observations with Sgr A* in the field of view, considered in this work)https://vizier.cds.unistra.fr/viz-bin/conesearch/J/MNRAS/454/1525/tablea4?https://vizier.iucaa.in/viz-bin/conesearch/J/MNRAS/454/1525/tablea4?http://vizieridia.saao.ac.za/viz-bin/conesearch/J/MNRAS/454/1525/tablea4?GETtext/xml+votable180.050000true266.41665-29.006390.0055555555555555566/28830https://cdsarc.cds.unistra.fr/viz-bin/moc/J/MNRAS/454/1525?format=asciiX-raydefaultJ/MNRAS/454/1525/ChandraList of all Chandra observations on Sgr A* performed between 1999 and 2014recnoRecord number assigned by the VizieR team. Should Not be used for identification.meta.recordintObsIDObservation identifiermeta.id;obs.param;obscharMode[I SH S] Instrument set-up (not in tablea4.dat) (1)instrcharTExp? Total exposure time (not in tablea4.dat)kstime.duration;obs.exposurefloatnullableExpCleaned exposure timekstime.duration;obs.exposurefloatObs.dateObservation date/time (YYYY-MM-DDThh:mm:ss)meta.notecharNb[1/10] Number of different blocks detected in our Bayesian block analysismeta.numberintNf[0/4] Number of flaring blocksmeta.numberfloatNblock[1/10]? Block numbermeta.idintnullableMJD1? Modified Julian Date, block start timedtime.epochdoublenullableMJD2? Modified Julian Date, block stop timedtime.epochdoublenullableDur? Durationstime.durationfloatnullableCR? Mean observed count rateph/sphot.count;em.X-rayfloatnullablee_CR? 1{sigma} uncertainty in CRph/sstat.errorfloatnullableFl? Fluence after subtraction of the average contribution of the non-flaring blocks (10^-10^erg/cm^2^)1e-13J.m**-2phot.fluence;em.gamma.hardfloatnullableTFl? Total flare fluence (10^-10^erg/cm^2^)1e-13J.m**-2phot.fluence;em.gamma.hardfloatnullable_RAPosition (as computed from The Chandra Archive Log Catalog, Cat. B/chandra) (right ascension part)degpos.eq.ra;meta.main_DEPosition (as computed from The Chandra Archive Log Catalog, Cat. B/chandra) (declination part)degpos.eq.dec;meta.mainJ/MNRAS/454/1525/tablea4List of all XMM-Newton observations with Sgr A* in the field of view, considered in this workMJD1? Modified Julian Date, block start timedtime.epochdoublenullablerecnoRecord number assigned by the VizieR team. Should Not be used for identification.meta.recordintObsIDObservation identifiermeta.id;obs.param;obscharExpCleaned exposure timekstime.duration;obs.exposurefloatObs.dateObservation date/time (YYYY-MM-DDThh:mm:ss)meta.notecharTime1? Start time (only in tablea4.dat)kstime.epochfloatnullableTime2? End time (only in tablea4.dat)kstime.epochfloatnullableNb[1/10] Number of different blocks detected in our Bayesian block analysismeta.numberintNf[0/4] Number of flaring blocksmeta.numberfloatn_Nf[a] Note on Nf (only in tablea4.dat) (2)meta.notecharNblock[1/10]? Block numbermeta.idintnullableMJD2? Modified Julian Date, block stop timedtime.epochdoublenullableDur? Durationstime.durationfloatnullableCR? Mean observed count rateph/sphot.count;em.X-rayfloatnullablee_CR? 1{sigma} uncertainty in CRph/sstat.errorfloatnullableFl? Fluence after subtraction of the average contribution of the non-flaring blocks (10^-10^erg/cm^2^)1e-13J.m**-2phot.fluence;em.gamma.hardfloatnullableTFl? Total flare fluence (10^-10^erg/cm^2^)1e-13J.m**-2phot.fluence;em.gamma.hardfloatnullable_RAPosition (as computed from XMM-Newton Observation Log Catalog, Cat. B/xmm) (right ascension part)degpos.eq.ra;meta.main_DEPosition (as computed from XMM-Newton Observation Log Catalog, Cat. B/xmm) (declination part)degpos.eq.dec;meta.main