Host Galaxy Line Diagnostics for the Candidate Tidal Disruption Events
  XMMSL1 J111527.3+180638 and PTF09axc
  We present results of our analysis of spectra of the host galaxies of the
candidate Tidal Disruption Events (TDEs) XMMSL1 J111527.3+180638 and PTF09axc
to determine the nature of these transients. We subtract the starlight
component from the host galaxy spectra to determine the origin of the nuclear
emission lines. Using a Baldwin-Phillips-Terlevich (BPT) diagram we conclude
that the host galaxy of XMMSL1 J111527.3+180638 is classified as a Seyfert
galaxy, suggesting this transient is likely to be caused by (extreme)
variability in the active galactic nucleus. We find that the host of PTF09axc
falls in the 'star-forming' region of the BPT-diagram, implying that the
transient is a strong TDE candidate. For both galaxies we find a WISE-colour
difference of $W1-W2<0.8$, which means there is no indication of a dusty torus
and therefore an active galactic nucleus, seemingly contradicting our BPT
finding for the host of XMMSL1 J111527.3+180638. We discuss possible reasons
for the discrepant results obtained through the two methods.
