| Title | The Rise and Fall of ASASSN-18pg: Following a TDE from Early to Late Times |
| Authors | Holoien, Thomas W. -S. Auchettl, Katie Tucker, Michael A. Shappee, Benjamin J. Patel, Shannon G. Miller-Jones, James C. A. Mockler, Brenna Groenewald, Daniel N. Hinkle, Jason T. Brown, Jonathan S. Kochanek, Christopher S. Stanek, K. Z. Chen, Ping Dong, Subo Prieto, Jose L. Thompson, Todd A. Beaton, Rachael L. Connor, Thomas Cowperthwaite, Philip S. Dahmen, Linnea French, K. Decker Morrell, Nidia Buckley, David A. H. Gromadzki, Mariusz Roy, Rupak Coulter, David A. Dimitriadis, Georgios Foley, Ryan J. Kilpatrick, Charles D. Piro, Anthony L. Rojas-Bravo, Cesar Siebert, Matthew R. Velzen, Sjoert van |
| Affiliation | Carnegie Inst Sci, 813 Santa Barbara St, Pasadena, CA 91101 USA Univ Copenhagen, Niels Bohr Inst, DARK, Lyngbyvej 2, DK-2100 Copenhagen, Denmark Univ Melbourne, Sch Phys, Parkville, Vic 3010, Australia ARC Ctr Excellence All Sky Astrophys 3 Dimens AST, Canberra, ACT, Australia Univ Calif Santa Cruz, Dept Astron & Astrophys, Santa Cruz, CA 95064 USA Univ Hawaii, Inst Astron, 2680 Woodlawn Dr, Honolulu, HI 96822 USA Curtin Univ, Int Ctr Radio Astron Research, GPO Box U1987, Perth, WA 6845, Australia South African Astron Observ, POB 9, ZA-7935 Cape Town, South Africa Southern African Large Telescope Fdn, POB 9, ZA-7935 Observatory, South Africa Ohio State Univ, Ctr Cosmol & AstroParticle Phys CCAPP, 191 W Woodruff Ave, Columbus, OH 43210 USA Ohio State Univ, Dept Astron, 140 West 18th Ave, Columbus, OH 43210 USA Peking Univ, Kavli Inst Astron & Astrophys, Yi He Yuan Rd 5, Beijing 100871, Peoples R China Univ Diego Portales, Nucleo Astron, Fac Ingn & Ciencias, Av Ejercito 441, Santiago, Chile Millennium Inst Astrophys, Santiago, Chile Princeton Univ, Dept Astrophys Sci, 4 Ivy Lane, Princeton, NJ 08544 USA Pomona Coll, Dept Phys & Astron, 610 N Coll Ave, Claremont, CA 91711 USA Carnegie Observ, Las Campanas Observ, Casilla 601, La Serena, Chile Univ Warsaw, Astron Observ, Al Ujazdowskie 4, PL-00478 Warsaw, Poland Interuniv Ctr Astron & Astrophys, Pune 411007, Maharashtra, India NYU, Ctr Cosmol & Particle Phys, New York, NY 10003 USA |
| Keywords | TIDAL DISRUPTION EVENT STARS SPECTROGRAPH TELESCOPE EVOLUTION MASSES FLARE POLARIZATION CALIBRATION RESOLUTION |
| Issue Date | Aug-2020 |
| Publisher | ASTROPHYSICAL JOURNAL |
| Abstract | We present nearly 500 days of observations of the tidal disruption event (TDE) ASASSN-18pg, spanning from 54 days before peak light to 441 days after peak light. Our data set includes X-ray, UV, and optical photometry, optical spectroscopy, radio observations, and the first published spectropolarimetric observations of a TDE. ASASSN-18pg was discovered on 2018 July 11 by the All-Sky Automated Survey for Supernovae (ASAS-SN) at a distance ofd = 78.6 Mpc; with a peak UV magnitude ofm 14, it is both one of the nearest and brightest TDEs discovered to-date. The photometric data allow us to track both the rise to peak and the long-term evolution of the TDE. ASASSN-18pg peaked at a luminosity ofL 2.4 x 10(44)erg s(-1), and its late-time evolution is shallower than a flux proportional to t(-5/3)power-law model, similar to what has been seen in other TDEs. ASASSN-18pg exhibited Balmer lines and spectroscopic features consistent with Bowen fluorescence prior to peak, which remained detectable for roughly 225 days after peak. Analysis of the two-component H alpha profile indicates that, if they are the result of reprocessing of emission from the accretion disk, the different spectroscopic lines may be coming from regions between similar to 10 and similar to 60 lt-days from the black hole. No X-ray emission is detected from the TDE, and there is no evidence of a jet or strong outflow detected in the radio. Our spectropolarimetric observations indicate that the projected emission region is likely not significantly aspherical, with the projected emission region having an axis ratio of greater than or similar to 0.65. |
| URI | http://hdl.handle.net/20.500.11897/591148 |
| ISSN | 0004-637X |
| DOI | 10.3847/1538-4357/ab9f3d |
| Indexed | SCI(E) |
| Appears in Collections: | 科维理天文与天体物理研究所 |
