Swift Observations of the TDE ASASSN-14li Show That It Remains Bright in UV and X-rays

ATel #8309; T. W.-S. Holoien (Ohio State), D. Grupe (Morehead State) K. Z. Stanek, C. S. Kochanek, J. S. Brown, D. Godoy-Rivera (Ohio State), B. J. Shappee (Hubble Fellow, Carnegie Observatories), J. L. Prieto (Diego Portales; MAS), D. Bersier (LJMU), Subo Dong, Ping Chen (KIAA-PKU)
on 20 Nov 2015; 06:07 UT
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Credential Certification: Thomas Holoien (tholoien@astronomy.ohio-state.edu)

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We have analyzed new Swift UVOT and XRT observations of the TDE ASASSN-14li (Holoien et al. 2015, MNRAS, in press), which has re-emerged from behind the Sun. The new UVOT data, obtained on 2015-11-14, show that the transient has faded only slightly in all UV filters during the ~3 months it was unobservable. Measurements for the last two Swift epochs are given in the tables below:

2015-11-14 data:

 
Filter   Mag     Unc 
  V     15.82   0.071 
  B     16.44   0.054 
  U     16.53   0.073 
 UVW1   17.05   0.076 
 UVM2   17.13   0.067 
 UVW2   16.99   0.067 

2015-08-12 data:

 
Filter   Mag     Unc 
  U     16.59   0.073 
 UVW1   16.92   0.085 
 UVM2   17.05   0.085 
 UVW2   16.80   0.058 

ASASSN-14li is also still clearly detected in the XRT data with a flux of 1.28e-11 ergs/s/cm^2 in the 0.3-10 keV band. This is a slightly higher flux than was measured previously (0.82e-11 ergs/s/cm^2 on 2015-08-12).

Further observations in all wavelengths are highly encouraged.

We thank the Swift team for approving and promptly scheduling these observations.