OPTICAL DISCOVERY OF PROBABLE STELLAR TIDAL DISRUPTION FLARES

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dc.contributor.authorvan Velzen, Sjoert
dc.contributor.authorFarrar, Glennys R
dc.contributor.authorGezari, Suvi
dc.contributor.authorMorrell, Nidia
dc.contributor.authorZaritsky, Dennis
dc.contributor.authorÖstman, Linda
dc.contributor.authorSmith, Mathew
dc.contributor.authorGelfand, Joseph
dc.contributor.authorDrake, Andrew J
dc.date.accessioned2021-10-08T07:20:36Z
dc.date.available2021-10-08T07:20:36Z
dc.date.issued2011
dc.description.abstractUsing archival Sloan Digital Sky Survey (SDSS) multi-epoch imaging data (Stripe 82), we have searched for the tidal disruption of stars by supermassive black holes in non-active galaxies. Two candidate tidal disruption events (TDEs) are identified. The TDE flares have optical blackbody temperatures of 2 Multiplication-Sign 10{sup 4} K and observed peak luminosities of M{sub g} = -18.3 and -20.4 ({nu}L{sub {nu}} = 5 Multiplication-Sign 10{sup 42}, 4 Multiplication-Sign 10{sup 43} erg s{sup -1}, in the rest frame); their cooling rates are very low, qualitatively consistent with expectations for tidal disruption flares. The properties of the TDE candidates are examined using (1) SDSS imaging to compare them to other flares observed in the search, (2) UV emission measured by GALEX, and (3) spectra of the hosts and of one of the flares. Our pipeline excludes optically identifiable AGN hosts, and our variability monitoring over nine years provides strong evidence that these are not flares in hidden AGNs. The spectra and color evolution of the flares are unlike any SN observed to date, their strong late-time UV emission is particularly distinctive, and they are nuclear at high resolution arguing against these being first cases of a previously unobserved class of SNemore » or more extreme examples of known SN types. Taken together, the observed properties are difficult to reconcile with an SN or an AGN-flare explanation, although an entirely new process specific to the inner few hundred parsecs of non-active galaxies cannot be excluded. Based on our observed rate, we infer that hundreds or thousands of TDEs will be present in current and next-generation optical synoptic surveys. Using the approach outlined here, a TDE candidate sample with O(1) purity can be selected using geometric resolution and host and flare color alone, demonstrating that a campaign to create a large sample of TDEs, with immediate and detailed multi-wavelength follow-up, is feasible. A by-product of this work is quantification of the power spectrum of extreme flares in AGNs.« less
dc.identifier.apacitationvan Velzen, S., Farrar, G. R., Gezari, S., Morrell, N., Zaritsky, D., Östman, L., ... Drake, A. J. (2011). OPTICAL DISCOVERY OF PROBABLE STELLAR TIDAL DISRUPTION FLARES. <i>The Astrophysical Journal</i>, 741(2), 73 - 177. http://hdl.handle.net/11427/34965en_ZA
dc.identifier.chicagocitationvan Velzen, Sjoert, Glennys R Farrar, Suvi Gezari, Nidia Morrell, Dennis Zaritsky, Linda Östman, Mathew Smith, Joseph Gelfand, and Andrew J Drake "OPTICAL DISCOVERY OF PROBABLE STELLAR TIDAL DISRUPTION FLARES." <i>The Astrophysical Journal</i> 741, 2. (2011): 73 - 177. http://hdl.handle.net/11427/34965en_ZA
dc.identifier.citationvan Velzen, S., Farrar, G.R., Gezari, S., Morrell, N., Zaritsky, D., Östman, L., Smith, M. & Gelfand, J. et al. 2011. OPTICAL DISCOVERY OF PROBABLE STELLAR TIDAL DISRUPTION FLARES. <i>The Astrophysical Journal.</i> 741(2):73 - 177. http://hdl.handle.net/11427/34965en_ZA
dc.identifier.issn0004-637X
dc.identifier.issn1538-4357
dc.identifier.ris TY - Journal Article AU - van Velzen, Sjoert AU - Farrar, Glennys R AU - Gezari, Suvi AU - Morrell, Nidia AU - Zaritsky, Dennis AU - Östman, Linda AU - Smith, Mathew AU - Gelfand, Joseph AU - Drake, Andrew J AB - Using archival Sloan Digital Sky Survey (SDSS) multi-epoch imaging data (Stripe 82), we have searched for the tidal disruption of stars by supermassive black holes in non-active galaxies. Two candidate tidal disruption events (TDEs) are identified. The TDE flares have optical blackbody temperatures of 2 Multiplication-Sign 10{sup 4} K and observed peak luminosities of M{sub g} = -18.3 and -20.4 ({nu}L{sub {nu}} = 5 Multiplication-Sign 10{sup 42}, 4 Multiplication-Sign 10{sup 43} erg s{sup -1}, in the rest frame); their cooling rates are very low, qualitatively consistent with expectations for tidal disruption flares. The properties of the TDE candidates are examined using (1) SDSS imaging to compare them to other flares observed in the search, (2) UV emission measured by GALEX, and (3) spectra of the hosts and of one of the flares. Our pipeline excludes optically identifiable AGN hosts, and our variability monitoring over nine years provides strong evidence that these are not flares in hidden AGNs. The spectra and color evolution of the flares are unlike any SN observed to date, their strong late-time UV emission is particularly distinctive, and they are nuclear at high resolution arguing against these being first cases of a previously unobserved class of SNemore » or more extreme examples of known SN types. Taken together, the observed properties are difficult to reconcile with an SN or an AGN-flare explanation, although an entirely new process specific to the inner few hundred parsecs of non-active galaxies cannot be excluded. Based on our observed rate, we infer that hundreds or thousands of TDEs will be present in current and next-generation optical synoptic surveys. Using the approach outlined here, a TDE candidate sample with O(1) purity can be selected using geometric resolution and host and flare color alone, demonstrating that a campaign to create a large sample of TDEs, with immediate and detailed multi-wavelength follow-up, is feasible. A by-product of this work is quantification of the power spectrum of extreme flares in AGNs.« less DA - 2011 DB - OpenUCT DP - University of Cape Town IS - 2 J1 - The Astrophysical Journal LK - https://open.uct.ac.za PY - 2011 SM - 0004-637X SM - 1538-4357 T1 - OPTICAL DISCOVERY OF PROBABLE STELLAR TIDAL DISRUPTION FLARES TI - OPTICAL DISCOVERY OF PROBABLE STELLAR TIDAL DISRUPTION FLARES UR - http://hdl.handle.net/11427/34965 ER - en_ZA
dc.identifier.urihttp://hdl.handle.net/11427/34965
dc.identifier.vancouvercitationvan Velzen S, Farrar GR, Gezari S, Morrell N, Zaritsky D, Östman L, et al. OPTICAL DISCOVERY OF PROBABLE STELLAR TIDAL DISRUPTION FLARES. The Astrophysical Journal. 2011;741(2):73 - 177. http://hdl.handle.net/11427/34965.en_ZA
dc.language.isoeng
dc.publisher.departmentDepartment of Mathematics and Applied Mathematics
dc.publisher.facultyFaculty of Science
dc.sourceThe Astrophysical Journal
dc.source.journalissue2
dc.source.journalvolume741
dc.source.pagination73 - 177
dc.source.urihttps://dx.doi.org/10.1088/0004-637X/741/2/73
dc.subject.otherastrophysics
dc.subject.othercosmology and astronomy
dc.subject.otherblack holes
dc.subject.othercolor
dc.subject.othergalactic evolution
dc.subject.othergalaxies
dc.subject.othergalaxy nuclei
dc.subject.otherluminosity
dc.subject.otherspectra
dc.subject.otherstars evolution
dc.subject.otheroptical properties
dc.subject.otherorganoleptic properties
dc.subject.otherphysical properties
dc.titleOPTICAL DISCOVERY OF PROBABLE STELLAR TIDAL DISRUPTION FLARES
dc.typeJournal Article
uct.type.publicationResearch
uct.type.resourceJournal Article
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