Deep Chandra Observations of the Compact Starburst Galaxy Henize 2-10: X-Rays from the Massive Black Hole
Abstract
We present follow-up X-ray observations of the candidate massive black hole (BH) in the nucleus of the low-mass, compact starburst galaxy Henize 2-10. Using new high-resolution observations from the Chandra X-ray Observatory totaling 200 ks in duration, as well as archival Chandra observations from 2001, we demonstrate the presence of a previously unidentified X-ray point source that is spatially coincident with the known nuclear radio source in Henize 2-10 (I.e., the massive BH). We show that the hard X-ray emission previously identified in the 2001 observation is dominated by a source that is distinct from the nucleus, with the properties expected for a high-mass X-ray binary. The X-ray luminosity of the nuclear source suggests the massive BH is radiating significantly below its Eddington limit (∼10{}-6 {L}{Edd}), and the soft spectrum resembles other weakly accreting massive BHs including Sagittarius A*. Analysis of the X-ray light curve of the nucleus reveals the tentative detection of a ∼9 hr periodicity, although additional observations are required to confirm this result. Our study highlights the need for sensitive high-resolution X-ray observations to probe low-level accretion, which is the dominant mode of BH activity throughout the universe.
- Publication:
-
The Astrophysical Journal
- Pub Date:
- October 2016
- DOI:
- 10.3847/2041-8205/830/2/L35
- arXiv:
- arXiv:1610.01598
- Bibcode:
- 2016ApJ...830L..35R
- Keywords:
-
- accretion;
- accretion disks;
- galaxies: active;
- galaxies: dwarf;
- galaxies: nuclei;
- X-rays: general;
- Astrophysics - High Energy Astrophysical Phenomena;
- Astrophysics - Astrophysics of Galaxies
- E-Print:
- Accepted for publication in ApJ Letters. 7 pages, 4 figures