During a close encounter between a star and a supermassive black hole,the star can get disrupted by the black hole's tidal forces,resulting in a tidal disruption event(TDE).The accretion of the star's material onto the black hole produces strong emission in different wavelength regimes.Here we report the discovery with the Roentgen Satellite(ROSAT)of an X-ray-selected transient source in an optically non-active galaxy.At the location R.A.:13h 31m57s.66 and decl.:-32°43′19″7 a sudden rise in X-ray luminosity by a factor of 8 within 8 days has been observed.Additionally,a very soft X-ray spectrum with a blackbody temperature kT = 0.1 keV and a peak luminosity of at least 1 × 1043 erg s-1 suggests a TDE interpretation,and the observed properties are very similar to previously identified soft X-ray(ROSAT)TDEs.An optical spectrum taken of the galaxy at the position of RXJ133157.6324319.7 six years after the X-ray outburst does not show any emission lines as would be expected from a persistent active galactic nucleus.The redshift of the galaxy is determined to be 0.051 based on absorption lines.It is therefore likely a member of the galaxy cluster A3560.The rise in X-ray luminosity happens within 8 days and thus appears to be fast for such an event.No X-ray emission was detected 170 days before and 165 days after the event,and none was detected 25 yr later with the Neil Gehrels Swift Observatory.The change in X-ray luminosity is at least a factor of 40.

J.Hampel;S.Komossa;J.Greiner;T.H.Reiprich;M.Freyberg;T.Erben

Argelander-Institut für Astronomie,Auf dem Hügel 71,D-53121 Bonn,Germany;Max-Planck Institut für Radioastronomie,Auf dem Hügel 69,D-53121 Bonn,Germany;National Astronomical Observatories,Chinese Academy of Science,Beijing 100101,China;Max-Planck Institute für Extraterrestrische Physik,Gieβenbachstrasse 1,D-85748 Garching,Germany

天文和天体物理学研究

[1]J.Hampel;S.Komossa;J.Greiner;T.H.Reiprich;M.Freyberg;T.Erben-.A New X-Ray Tidal Disruption Event Candidate with Fast Variability)[J].天文和天体物理学研究,2022(05):28-35

supermassive,Roentgen,ROSAT,31m57s,decl,TDEs,RXJ133157,A3560,Neil,Gehrels

New,Ray,Tidal,Disruption,Event,Candidate,Fast,Variability,During,close,encounter,between,star,hole,can,get,disrupted,by,tidal,forces,resulting,disruption,event,accretion,material,onto,produces,strong,emission,different,wavelength,regimes,Here,report,discovery,Satellite,ray,selected,transient,source,optically,active,galaxy,At,location,13h,sudden,rise,luminosity,within,days,has,been,observed,Additionally,soft,spectrum,blackbody,temperature,kT,keV,peak,least,erg,suggests,interpretation,properties,are,similar,previously,identified,An,taken,position,six,years,after,outburst,does,not,show,any,lines,would,expected,from,persistent,galactic,nucleus,redshift,determined,absorption,It,therefore,likely,member,cluster,happens,thus,appears,fast,such,No,was,detected,before,none,yr,later,Swift,Observatory,change

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