TDE Hosts are Green and Centrally Concentrated: Signatures of a Post-Merger System. (arXiv:2010.10738v2 [astro-ph.HE] UPDATED)
<a href="http://arxiv.org/find/astro-ph/1/au:+Hammerstein_E/0/1/0/all/0/1">Erica Hammerstein</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Gezari_S/0/1/0/all/0/1">Suvi Gezari</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Velzen_S/0/1/0/all/0/1">Sjoert van Velzen</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Cenko_S/0/1/0/all/0/1">S. Bradley Cenko</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Roth_N/0/1/0/all/0/1">Nathaniel Roth</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Ward_C/0/1/0/all/0/1">Charlotte Ward</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Frederick_S/0/1/0/all/0/1">Sara Frederick</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Hung_T/0/1/0/all/0/1">Tiara Hung</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Graham_M/0/1/0/all/0/1">Matthew Graham</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Foley_R/0/1/0/all/0/1">Ryan J. Foley</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Bellm_E/0/1/0/all/0/1">Eric C. Bellm</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Cannella_C/0/1/0/all/0/1">Christopher Cannella</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Drake_A/0/1/0/all/0/1">Andrew J. Drake</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Kupfer_T/0/1/0/all/0/1">Thomas Kupfer</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Laher_R/0/1/0/all/0/1">Russ R. Laher</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Mahabal_A/0/1/0/all/0/1">Ashish A. Mahabal</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Masci_F/0/1/0/all/0/1">Frank J. Masci</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Riddle_R/0/1/0/all/0/1">Reed Riddle</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Rojas_Bravo_C/0/1/0/all/0/1">César Rojas-Bravo</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Smith_R/0/1/0/all/0/1">Roger Smith</a>
We study the properties of the galaxies hosting the first 19 tidal disruption
events (TDEs) detected with the Zwicky Transient Facility (ZTF) within the
context of a carefully constructed, representative host galaxy sample. We find
that the ZTF sample of TDE hosts is dominated by compact “green valley”
galaxies. After we restrict the comparison sample to galaxies with a similar
concentration, as measured by Sersic index, we find this green valley over
representation is even larger. That is, concentrated red sequence galaxies are
not producing TDEs at elevated levels. We present host galaxy spectra which
show that E+A galaxies are overrepresented in the ZTF sample by a factor of
$approx$22, which is lower than previous TDE host galaxy studies have found.
We find that this overrepresentation can be fully accounted for when taking
into account the masses, colors, and S’ersic indices of the ZTF TDE hosts. The
combination of both green colors and high S’ersic index of the typical TDE
host galaxy could be explained if the TDE rate is temporarily enhanced
following a merger that leads to a higher central concentration of stars.
We study the properties of the galaxies hosting the first 19 tidal disruption
events (TDEs) detected with the Zwicky Transient Facility (ZTF) within the
context of a carefully constructed, representative host galaxy sample. We find
that the ZTF sample of TDE hosts is dominated by compact “green valley”
galaxies. After we restrict the comparison sample to galaxies with a similar
concentration, as measured by Sersic index, we find this green valley over
representation is even larger. That is, concentrated red sequence galaxies are
not producing TDEs at elevated levels. We present host galaxy spectra which
show that E+A galaxies are overrepresented in the ZTF sample by a factor of
$approx$22, which is lower than previous TDE host galaxy studies have found.
We find that this overrepresentation can be fully accounted for when taking
into account the masses, colors, and S’ersic indices of the ZTF TDE hosts. The
combination of both green colors and high S’ersic index of the typical TDE
host galaxy could be explained if the TDE rate is temporarily enhanced
following a merger that leads to a higher central concentration of stars.
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