PS18kh: A New Tidal Disruption Event with a Non-axisymmetric Accretion Disk
PS18kh: A New Tidal Disruption Event with a Non-axisymmetric Accretion Disk
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DOI：
10.3847/1538-4357/ab2ae1
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发表时间：
2018-08
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通讯作者：
T. Holoien;M. Huber;B. Shappee;M. Eracleous;K. Auchettl;J. Brown;M. Tucker;K. Chambers;C. Kochanek;K. Stanek;A. Rest;A. Rest;D. Bersier;R. Post;G. Aldering;K. Ponder;J. Simon;E. Kankare;D. Dong;G. Hallinan;N. Reddy;R. Sanders;M. Topping;Pan-Starrs;J. Bulger;T. Lowe;E. Magnier;A. Schultz;C. Waters;M. Willman;D. Wright;D. Young;Asas-Sn;S. Dong;J. Prieto;J. Prieto;T. Thompson;L. Denneau;H. Flewelling;A. Heinze;S. Smartt;K. Smith;B. Stalder;J. Tonry;H. Weiland
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作者：
T. Holoien;M. Huber;B. Shappee;M. Eracleous;K. Auchettl;J. Brown;M. Tucker;K. Chambers;C. Kochanek;K. Stanek;A. Rest;A. Rest;D. Bersier;R. Post;G. Aldering;K. Ponder;J. Simon;E. Kankare;D. Dong;G. Hallinan;N. Reddy;R. Sanders;M. Topping;Pan-Starrs;J. Bulger;T. Lowe;E. Magnier;A. Schultz;C. Waters;M. Willman;D. Wright;D. Young;Asas-Sn;S. Dong;J. Prieto;J. Prieto;T. Thompson;L. Denneau;H. Flewelling;A. Heinze;S. Smartt;K. Smith;B. Stalder;J. Tonry;H. Weiland
我们介绍了在SDSS J075654.53+341543.6（d = 322 Mpc）中心发现的PS18 kh潮汐破裂事件的发现。我们的数据集包括来自Pan-STARRS，超新星全天空自动调查和小行星陆地撞击最后警报系统的发现前调查数据，以及来自地面望远镜和Swift的高节奏，多波长后续数据，从峰值光之前的56天到之后的75天。PS18 kh的光学/紫外辐射非常适合作为黑体，温度范围从T 12，000 K到T 25，000 K，其峰值亮度为L 8.8 × 1043 erg s−1。PS18 kh在整个观测期间的辐射E =（3.45 ± 0.22）× 1050 erg，上升至峰值时释放E =（1.42 ± 0.20）× 1050 erg。PS18 kh的光谱显示出一个不断变化的四方形/双峰Hα发射特征，随着时间的推移变得更加突出。我们用非轴对称吸积盘模型来描述Hα线的轮廓及其演化。我们发现，在早期的高吸积率导致磁盘发出风修改的形状的线轮廓，使其钟形。在晚些时候，风变得光学薄，允许非轴对称扰动显示在线轮廓。盘的线发射部分从环60 rg延伸到外半径1400 rg，并且扰动可以表示为盘的外环中的偏心率或内盘中的螺旋臂。
We present the discovery of PS18kh, a tidal disruption event discovered at the center of SDSS J075654.53+341543.6 (d ≃ 322 Mpc) by the Pan-STARRS Survey for Transients. Our data set includes pre-discovery survey data from Pan-STARRS, the All-sky Automated Survey for Supernovae, and the Asteroid Terrestrial-impact Last Alert System as well as high-cadence, multiwavelength 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 ≃ 12,000 K to T ≃ 25,000 K and it peaked at a luminosity of L ≃ 8.8 × 1043 erg s−1. PS18kh radiated E = (3.45 ± 0.22) × 1050 erg over the period of observation, with (1.42 ± 0.20) × 1050 erg being released during the rise to peak. Spectra of PS18kh show a changing, boxy/double-peaked Hα emission feature, which becomes more prominent over time. We use models of non-axisymmetric accretion disks to describe the profile of the Hα 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 rin ∼ 60rg to an outer radius of rout ∼ 1400rg 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.