An Ultraluminous Supersoft Source in a Dwarf Galaxy of A85: An Intermediate-mass Black Hole Candidate
| Autor: | Marko Mićić, Dacheng Lin, Jimmy Irwin |
|---|---|
| Rok vydání: | 2022 |
| Předmět: |
High Energy Astrophysical Phenomena (astro-ph.HE)
Cosmology and Nongalactic Astrophysics (astro-ph.CO) Space and Planetary Science Astrophysics::High Energy Astrophysical Phenomena FOS: Physical sciences Astrophysics::Solar and Stellar Astrophysics Astronomy and Astrophysics Astrophysics::Earth and Planetary Astrophysics Astrophysics::Cosmology and Extragalactic Astrophysics Astrophysics - High Energy Astrophysical Phenomena Astrophysics::Galaxy Astrophysics Astrophysics - Cosmology and Nongalactic Astrophysics |
| Zdroj: | The Astrophysical Journal. 928:117 |
| ISSN: | 1538-4357 0004-637X |
| DOI: | 10.3847/1538-4357/ac56df |
| Popis: | We study a large sample of dwarf galaxies using archival Chandra X-ray observations, with the aim of detecting accreting intermediate-mass black holes (IMBHs). IMBHs are expected to inhabit dwarf galaxies and to produce specific signatures in terms of luminosity and X-ray spectra. We report the discovery of an X-ray source associated with an Abell 85 dwarf galaxy that fits the IMBH description. The stellar mass of the host galaxy is estimated to be 2 $\times$ 10$^8$ $M_\odot$, which makes it one of the least massive galaxies to potentially host an accreting black hole. The source is detected in the soft band, under 1 keV, while undetected at higher energies. The X-ray luminosity is $\approx$ 10$^{41}$ erg s$^{-1}$, making it almost three orders of magnitude more luminous than the most luminous stellar-mass supersoft emitters. From the galaxy stellar mass vs. black hole mass relation, we estimate the mass to be within the intermediate regime. Another method that resulted in an intermediate mass relies on the fact that supersoft emission is expected to be associated with high accretion rates, approaching the Eddington limit. We suggest that the observed offset of the X-ray source from the galactic center ($\approx$ 1.8 kpc) is due to galaxy interactions, and we present evidence from the literature that supports the relation between black hole activity and galaxy interactions. Accepted for publication in ApJ |
| Databáze: | OpenAIRE |
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