Confirming the First Supermassive Black Hole in a Dwarf Starburst Galaxy
Abstract
In the modern universe, supermassive black holes lie at the heart of most, if not all, galaxies with bulges. However, the birth and growth of the first "seed" black holes, back in the earlier universe, is observationally unconstrained. Reines et al. {2011} have recently discovered a candidate million-solar mass black hole in the bulgeless dwarf starburst galaxy Henize 2-10, offering the first opportunity to study a growing black hole in a nearby galaxy much like those in the infant universe. The case for an accreting black hole in Henize 2-10 is strong {e.g. co-spatial non-thermal radio and hard X-ray point sources}, but not watertight. Our proposal aims to confirm {or refute} the presence of this candidate black hole using STIS optical spectroscopy to trace the kinematics and ionization conditions in its immediate vicinity. Existing HST observations show a marginally resolved H-alpha knot coincident with the radio and X-ray point source, so our primary aim is to detect a compact rotating disk of ionized gas, directly yielding a black hole mass. Our secondary aim is to find evidence for AGN-related emission line signatures at the location of the H-alpha knot, and possibly along a narrow jet-like filament. Confirming the presence of a supermassive black hole in Henize 2-10 with these HST observations has immediate implications for our understanding of the birth and early evolution of the first black holes in the high-redshift universe.
- Publication:
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HST Proposal
- Pub Date:
- October 2011
- Bibcode:
- 2011hst..prop12584R