TY - JOUR
T1 - Swift J2058.4+0516: Discovery of a Possible Second Relativistic Tidal Disruption Flare?
T2 - Discovery of a Possible Second Relativistic Tidal Disruption Flare?
AU - Cenko, S. Bradley
AU - Krimm, Hans A.
AU - Horesh, Assaf
AU - Rau, Arne
AU - Frail, Dale A.
AU - Kennea, Jamie A.
AU - Levan, Andrew J.
AU - Holland, Stephen T.
AU - Butler, Nathaniel R.
AU - Quimby, Robert M.
AU - Bloom, Joshua S.
AU - Filippenko, Alexei V.
AU - Gal-Yam, Avishay
AU - Greiner, Jochen
AU - Kulkarni, S.~R.
AU - Ofek, Eran O.
AU - Olivares E., Felipe
AU - Schady, Patricia
AU - Silverman, Jeffrey M.
AU - Tanvir, Nial R.
AU - Xu, Dong
PY - 2012/6/15
Y1 - 2012/6/15
N2 - We report the discovery by the Swift hard X-ray monitor of the transient source Swift J2058.4+0516 (Sw J2058+05). Our multi-wavelength follow-up campaign uncovered a long-lived (duration months), luminous X-ray (L X, iso ≈ 3 × 1047 erg s–1) and radio (νL ν, iso ≈ 1042 erg s–1) counterpart. The associated optical emission, however, from which we measure a redshift of 1.1853, is relatively faint, and this is not due to a large amount of dust extinction in the host galaxy. Based on numerous similarities with the recently discovered GRB 110328A/Swift J164449.3+573451 (Sw J1644+57), we suggest that Sw J2058+05 may be the second member of a new class of relativistic outbursts resulting from the tidal disruption of a star by a supermassive black hole. If so, the relative rarity of these sources (compared with the expected rate of tidal disruptions) implies that either these outflows are extremely narrowly collimated (θ < 1°) or only a small fraction of tidal disruptions generate relativistic ejecta. Analogous to the case of long-duration gamma-ray bursts and core-collapse supernovae, we speculate that rapid spin of the black hole may be a necessary condition to generate the relativistic component. Alternatively, if powered by gas accretion (i.e., an active galactic nucleus (AGN)), Sw J2058+05 would seem to represent a new mode of variability in these sources, as the observed properties appear largely inconsistent with known classes of AGNs capable of generating relativistic jets (blazars, narrow-line Seyfert 1 galaxies).
AB - We report the discovery by the Swift hard X-ray monitor of the transient source Swift J2058.4+0516 (Sw J2058+05). Our multi-wavelength follow-up campaign uncovered a long-lived (duration months), luminous X-ray (L X, iso ≈ 3 × 1047 erg s–1) and radio (νL ν, iso ≈ 1042 erg s–1) counterpart. The associated optical emission, however, from which we measure a redshift of 1.1853, is relatively faint, and this is not due to a large amount of dust extinction in the host galaxy. Based on numerous similarities with the recently discovered GRB 110328A/Swift J164449.3+573451 (Sw J1644+57), we suggest that Sw J2058+05 may be the second member of a new class of relativistic outbursts resulting from the tidal disruption of a star by a supermassive black hole. If so, the relative rarity of these sources (compared with the expected rate of tidal disruptions) implies that either these outflows are extremely narrowly collimated (θ < 1°) or only a small fraction of tidal disruptions generate relativistic ejecta. Analogous to the case of long-duration gamma-ray bursts and core-collapse supernovae, we speculate that rapid spin of the black hole may be a necessary condition to generate the relativistic component. Alternatively, if powered by gas accretion (i.e., an active galactic nucleus (AGN)), Sw J2058+05 would seem to represent a new mode of variability in these sources, as the observed properties appear largely inconsistent with known classes of AGNs capable of generating relativistic jets (blazars, narrow-line Seyfert 1 galaxies).
KW - accretion, accretion disks, black hole physics, galaxies: nuclei, X-rays: bursts, X-rays: individual: Sw J1644+57, Astrophysics - High Energy Astrophysical Phenomena
U2 - 10.1088/0004-637X/753/1/77
DO - 10.1088/0004-637X/753/1/77
M3 - Article
SN - 0004-637X
VL - 753
SP - 77
JO - Astrophysical Journal
JF - Astrophysical Journal
ER -