AstroNote 2019-88

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DRAFT
2019-09-05 02:52:28
Type: Object/s-Discovery/Classification
Classification of AT2019meg as a tidal disruption event, evidence for an increasing temperature
Authors: Sjoert van Velzen (UMD), Suvi Gezari (UMD), Charlotte Ward (UMD), Sara Frederick (UMD), Erica Hammerstein (UMD), S. Bardley Cenko (UMD)
Abstract:
We classify AT2019meg as a tidal disruption event based on our optical spectra and NUV data from Swift/UVOT. The optical spectrum shows broad Halpha and Hbeta emission and a blue continuum, as well as narrow lines from the star-forming galaxy host at z=0.152. The Swift+ZTF data yield a high blackbody temperature (~3e4 K) that appears to be increasing ~1 month after peak.

As part of our systematic search of TDEs in ZTF data (van Velzen et al. 2019), we obained an optical spectrum of the nuclear transient AT2019meg on 2019 Jul 31 with SEDM. Our first SEDM specturm is consistent with the report in AstroNote 2019-59 (posted 2019 Aug 01), which mentioned a blue continuum and flagged this transient as interesting based on its luminosity and light curve shape. We obtained a second spectrum on 2019 Aug 27 with DCT, which shows a persistent blue continuum, and broad Halpha and Hbeta emission lines consistent with a hydrogen-rich tidal disruption event spectrum (TDE-H). 

We obtained Swift observations on 2019 Aug 20 and 2019 Sep 04, and measure an increasing blackbody temperature from the ZTF difference flux and the host-subtracted Swift/UVOT photometry from 10^4.3 K to 10^4.5 K in the first and second Swift epoch, respecively. The Swift/XRT images show no X-ray detection. However, in analog with the TDE ASASSN-15oi, we might expect an increase in the X-ray counts in the next few months. TOO XMM/Newton observations have been triggered. 

Show current TNS values
CatalogNameReported RAReported DECReported Obj-TypeReported RedshiftHost NameHost RedshiftRemarksTNS RATNS DECTNS Obj-TypeTNS Redshift
TNS2019meg [ZTF19abhhjcc]18:45:16.178+44:26:19.14TDE0.15218:45:16.180+44:26:19.21