| 16th of March 2022 |
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| ATNF Colloquium |
| Tracing the first massive black hole seeds and their merger-driven growth with the Zwicky Transient Facility |
| Charlotte Ward (University of Maryland) |
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Abstract:
Over the last 3 years, the Zwicky Transient Facility (ZTF) has
demonstrated the capability of wide-field time-domain surveys to
discover the important black hole populations which trace the
formation of the first massive black hole seeds and their
merger-driven growth. For instance, our search for off-nuclear active
galactic nuclei (AGN) in ZTF revealed 9 supermassive black holes
(SMBHs) which may have been ejected from their host galaxy by
gravitational wave recoil from SMBH mergers with misaligned
spins. Likewise, our search for variable intermediate mass black holes
(IMBHs) in dwarf galaxies found 200 new IMBH candidates, most of which
could not have been found via their spectroscopic signatures
alone. Finally, our study of periodically variable AGN with
double-peaked broad emission lines revealed how single AGN can mimic
SMBH binaries and mergers. We found these rare black holes amongst
large populations of AGN in part by using innovative forward modelling
techniques to improve photometric sensitivity and measure the
separations between variable objects and their host galaxies. Our work
is an exciting precursor to the Legacy Survey of Space and Time which
we expect to detect substantially larger populations of recoiling SMBH
and IMBH candidates.
The top images above show ZTF light curves of two variable AGN with double-peaked Balmer broad lines. The bottom images show spectra and models of Hα emission from the accretion disk of two off-nuclear AGN candidates. |