J/A+A/664/A158ivo://CDS.VizieR/J/A+A/664/A158doi:10.26093/cds/vizier.36640158CDSReynolds T.M.Mattila S.Efstathiou A.Kankare E.Kool E.Ryder S.,Pena-Monino L.Perez-Torres M.A.2022-08-29T10:17:05Z2022-08-25T08:48:34ZCDS support team

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

cds-question@unistra.frgalaxiesinfrared-sourcesEnergetic nuclear outbursts have been discovered in luminous and ultraluminous infrared galaxies (U/LIRGs) at unexpectedly high rates. To investigate this population of transients, we performed a search in mid-IR data from the Wide-field Infrared Survey Explorer (WISE) satellite and its NEOWISE survey to detect and characterise luminous and smoothly evolving transients in a sample of 215 U/LIRGs. We report three new transients, all with {Delta}L>10^43^erg/s, in addition to two previously known cases. Their host galaxies are all part of major galaxy mergers, and through radiative transfer model fitting we find that all have a significant contribution from an active galactic nucleus (AGN). We characterised the transients through measurements of their luminosities and resulting energetics, all of which are between 10^50.9^erg and 10^52.2^erg. The IR emission of the five transients was found to be consistent with re-radiation by the hot dust of emission at shorter wavelengths, presumably originating from an accretion event, onto the supermassive black hole. The corresponding transient rate of (1.6-4.6)x10^-3^/yr/galaxy is over an order of magnitude higher than the rate of large amplitude flares shown by AGN in the optical. We suggest that the observed transients are part of a dust-obscured population of tidal disruption events (TDEs) that have remained out of the reach of optical surveys due to the obscuring dust. In one case, this is supported by our radio observations. We also discuss other plausible explanations. The observed rate of events is significantly higher than optical TDE rates, which can be expected in U/LIRG hosts undergoing a major galaxy merger with increased stellar densities in the nuclear regions. Continued searches for such transients and their multi-wavelength follow-up is required to constrain their rate and nature.2022A&A...664A.158Rhttps://cdsarc.cds.unistra.fr/viz-bin/cat/J/A+A/664/A158CatalogResearchIsServedByTAP VizieR generic serviceIsServedByConesearch servicehttps://cds.unistra.fr/vizier-org/licences_vizier.htmlhttps://vizier.cds.unistra.fr/viz-bin/VizieR-2?-source=J/A+A/664/A158https://vizier.iucaa.in/viz-bin/VizieR-2?-source=J/A+A/664/A158http://vizieridia.saao.ac.za/viz-bin/VizieR-2?-source=J/A+A/664/A158https://vizier.cds.unistra.fr/viz-bin/votable?-source=J/A+A/664/A158https://vizier.iucaa.in/viz-bin/votable?-source=J/A+A/664/A158http://vizieridia.saao.ac.za/viz-bin/votable?-source=J/A+A/664/A158GETtext/xml+votablehttps://tapvizier.cds.unistra.fr/TAPVizieR/tapCone search capability for table J/A+A/664/A158/tablea1 (U/LIRGs used for the study)https://vizier.cds.unistra.fr/viz-bin/conesearch/J/A+A/664/A158/tablea1?https://vizier.iucaa.in/viz-bin/conesearch/J/A+A/664/A158/tablea1?http://vizieridia.saao.ac.za/viz-bin/conesearch/J/A+A/664/A158/tablea1?GETtext/xml+votable180.050000true2.472625.92390.0055555555555555566/226 231 286 295 538 627 629 650 700 747 1130 1276 1521 1677 1701-1702 1865 1918 2309 2363 2433 2518 2680 3364 3446 3824 3934 4993 5116 5130 5523 5816 5865 6098 6348 6781 7552 7763 8106 8111 8266 8482 8562 8673 8997 9133 9770 9895 10081 10144 10210 10281 10357 10404 10453 10465 10628 10716 11029 11101 11180 11206 11908 12537 13021 13184 13459 13523 13632 13925 14164 14948 15323 15333 15570 16045 16091 16690 16755 16758 17075 17183 17252 17492 17506 17736 17904 18406 18432 18714 18753 18897 18932 19283 19619 20060-20061 20118 20208 20254 20371 20875 20895-20896 21016 21416 21747 22468 22654 22721 22792 23339 23921 24123 24144 24232 24293 24584 24631 24855 24958 25136 25462 25610 26028 26035 26198 26264 26298 26324 26811 26932 27340 27537 28188 28393 28999 29439 29680 29937 30027 30383 30580 30810 30822 30879 31081 31158 31430 31503 31971 32187 32548 32740 34010 34397 34531 34627 34695 35067 35576 35602 35608 36188 37113 37559 37564 37821 38129 38139 38246 38285 38786 38887 38935 39472 39960 40082 40801 41276 41402 41430 41982 42010 42855 42923 43078 43082 43107 43147 43298 43389 43564 43677 43925 43994 44066 44626 44671 45387 46077 46079 46130 46296 46399 46794 46811 46882 47029 47162 47235 47543 47854 48665https://cdsarc.cds.unistra.fr/viz-bin/moc/J/A+A/664/A158?format=asciiInfrareddefaultJ/A+A/664/A158/tablea1U/LIRGs used for the studySimbadNameSimbad column added by the CDSmeta.idcharnullablerecnoRecord number assigned by the VizieR team. Should Not be used for identification.meta.recordintRBGSRBGS namemeta.id;meta.maincharAllWISEAllWISE name (JHHMMSS.ss+DDMMSS.s)meta.idcharRAJ2000Rigth ascension (J2000)degpos.eq.ra;meta.mainDEJ2000Declination (J2000)degpos.eq.dec;meta.mainDistDistanceMpcpos.distancefloatLIRInfrared luminositylog(solLum)phys.luminosity;em.IRfloat