Abstract for Proposal 095300

Unveiling TDE Accretion Disks at Late Times with UV Spectroscopy and XMM-Newton

The tidal disruption of a star by a supermassive black hole produces broadband emission as the debris forms a disk and accretes. Most previous work has focused on observations near maximum light when the accretion disk may be obscured by a reprocessing layer. However, recent observations have shown that long-lived UV plateaus may be common in these events at late times as the unobscured accretion disk becomes visible. We propose the first STIS UV spectroscopic observations on these timescales combined with XMM-Newton observations to diagnose the properties of the accretion disk, the spectral shape of the ionizing continuum, and how these are reflected in the broad emission lines. These observations will open a new window of investigation into late-time multiwavelength properties of TDEs and will strengthen connections between previous work on AGN accretion and newly formed TDE accretion disks.



Details on Observing Strategy and Trigger Criteria
Trigger criteria: - Our trigger criteria are for TDEs with UV emission consistent with a late-time plateau (>200 days after optical discovery), with a target time frame of 200–500 d after discovery

Required reaction time: - Reaction time 15-30 days

Observing strategy: - HST and XMM within 15 days