The Rise and Fall of ASASSN-18pg: Following a TDE from Early to Late Times

Research output: Contribution to journalJournal articleResearchpeer-review

Documents

  • Fulltext

    Submitted manuscript, 5.19 MB, PDF document

  • Thomas W. -S. Holoien
  • Katie Auchettl
  • Michael A. Tucker
  • Benjamin J. Shappee
  • Shannon G. Patel
  • James C. A. Miller-Jones
  • Brenna Mockler
  • Daniel N. Groenewald
  • Jason T. Hinkle
  • Jonathan S. Brown
  • Christopher S. Kochanek
  • K. Z. Stanek
  • Ping Chen
  • Subo Dong
  • Jose L. Prieto
  • Todd A. Thompson
  • Rachael L. Beaton
  • Thomas Connor
  • Philip S. Cowperthwaite
  • Linnea Dahmen
  • And 13 others
  • K. Decker French
  • Nidia Morrell
  • David A. H. Buckley
  • Mariusz Gromadzki
  • Rupak Roy
  • David A. Coulter
  • Georgios Dimitriadis
  • Ryan J. Foley
  • Charles D. Kilpatrick
  • Anthony L. Piro
  • Cesar Rojas-Bravo
  • Matthew R. Siebert
  • Sjoert van Velzen

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.

Original languageEnglish
Article number161
JournalAstrophysical Journal
Volume898
Issue number2
Number of pages19
ISSN0004-637X
DOIs
Publication statusPublished - 1 Aug 2020

    Research areas

  • Black holes, Accretion, Galaxy accretion disks, Black hole physics, Supermassive black holes, Tidal disruption, TIDAL DISRUPTION EVENT, STARS, SPECTROGRAPH, TELESCOPE, EVOLUTION, MASSES, FLARE, POLARIZATION, CALIBRATION, RESOLUTION

ID: 247873449