Chandra Survey of Nearby Galaxies: A Significant Population of Candidate Central Black Holes in Late-type Galaxies

Journal Article · Tue Jun 20 04:00:00 EDT 2017 · Astrophysical Journal

DOI:https://doi.org/10.3847/1538-4357/AA7634· OSTI ID:22876093

She, Rui; Feng, Hua ^[1]; Ho, Luis C. ^[2]

---

1. Department of Engineering Physics and Center for Astrophysics, Tsinghua University, Beijing 100084 (China)
2. Kavli Institute for Astronomy and Astrophysics, Peking University, Beijing 100087 (China)

Based on the Chandra data archive as of 2016 March, we have identified 314 candidate active galactic nuclei in 719 galaxies located closer than 50 Mpc, among them late-type galaxies (Hubble types Sc and later) that previously had been classified from optical observations as containing star-forming (H ii) nuclei. These late-type galaxies comprise a valuable subsample to search for low-mass (≲10{sup 6} M{sub ⊙}) central black holes. For the sample as a whole, the overall dependence of the fraction of active nuclei on galaxy type and nuclear spectral classification is consistent with previous results based on optical surveys. We detect 51 X-ray cores among the 163 H ii nuclei and estimate that, very conservatively, ∼74% of them with luminosities above 10{sup 38} erg s{sup −1} are not contaminated by X-ray binaries; the fraction increases to ∼92% for X-ray cores with a luminosity of 10{sup 39} erg s{sup −1} or higher. This allows us to estimate a black hole occupation fraction of ≳21% in these late-type galaxies, many of which are bulgeless.

• OSTI ID: 22876093
• Journal Information: Astrophysical Journal, Journal Name: Astrophysical Journal Journal Issue: 2 Vol. 842; ISSN ASJOAB; ISSN 0004-637X
• Country of Publication: United States
• Language: English

Related Subjects

79 ASTRONOMY AND ASTROPHYSICS
BLACK HOLES
CLASSIFICATION
GALAXY NUCLEI
LUMINOSITY
MASS
SEYFERT GALAXIES
STARS
X-RAY GALAXIES