학술논문
PS18kh: A New Tidal Disruption Event with a Non-Axisymmetric Accretion Disk
Document Type
Working Paper
Author
Holoien, T. W. -S.; Huber, M. E.; Shappee, B. J.; Eracleous, M.; Auchettl, K.; Brown, J. S.; Tucker, M. A.; Chambers, K. C.; Kochanek, C. S.; Stanek, K. Z.; Rest, A.; Bersier, D.; Post, R. S.; Aldering, G.; Ponder, K. A.; Simon, J. D.; Kankare, E.; Dong., D.; Hallinan, G.; Reddy, N. A.; Sanders, R. L.; Topping, M. W.; Bulger, J.; Lowe, T. B.; Magnier, E. A.; Schultz, A. S. B.; Waters, C. Z.; Willman, M.; Wright, D.; Young, D. R.; Dong, Subo; Prieto, J. L.; Thompson, Todd A.; Denneau, L.; Flewelling, H.; Heinze, A. N.; Smartt, S. J.; Smith, K. W.; Stalder, B.; Tonry, J. L.; Weiland, H.
Source
The Astrophysical Journal, 880, 120 (2019)
Subject
Language
Abstract
We present the discovery of PS18kh, a tidal disruption event (TDE) discovered at the center of SDSS J075654.53+341543.6 ($d\simeq322$ Mpc) by the Pan-STARRS Survey for Transients. Our dataset includes pre-discovery survey data from Pan-STARRS, the All-Sky Automated Survey for Supernovae (ASAS-SN), and the Asteroid Terrestrial-impact Last Alert System (ATLAS) as well as high-cadence, multi-wavelength follow-up data from ground-based telescopes and Swift, spanning from 56 days before peak light until 75 days after. The optical/UV emission from PS18kh is well-fit as a blackbody with temperatures ranging from $T\simeq12000$ K to $T\simeq25000$ K and it peaked at a luminosity of $L\simeq8.8\times10^{43}$ ergs s$^{-1}$. PS18kh radiated $E=(3.45\pm0.22)\times10^{50}$ ergs over the period of observation, with $(1.42\pm0.20)\times10^{50}$ ergs being released during the rise to peak. Spectra of PS18kh show a changing, boxy/double-peaked H$\alpha$ emission feature, which becomes more prominent over time. We use models of non-axisymmetric accretion disks to describe the profile of the H$\alpha$ line and its evolution. We find that at early times the high accretion rate leads the disk to emit a wind which modifies the shape of the line profile and makes it bell-shaped. At late times, the wind becomes optically thin, allowing the non-axisymmetric perturbations to show up in the line profile. The line-emitting portion of the disk extends from $r_{\rm in}\sim60r_{\rm g}$ to an outer radius of $r_{\rm out}\sim1400r_{\rm g}$ and the perturbations can be represented either as an eccentricity in the outer rings of the disk or as a spiral arm in the inner disk.
Comment: 27 pages, 13 figures, 8 tables. Updated to reflect changes made in the published version. A table containing the host-subtracted photometry presented in this manuscript is included in machine-readable format as an ancillary file
Comment: 27 pages, 13 figures, 8 tables. Updated to reflect changes made in the published version. A table containing the host-subtracted photometry presented in this manuscript is included in machine-readable format as an ancillary file