The demographics of central massive black holes in low-mass early-type galaxies. Issue Volume 14:Issue S353(2019) (June 2019)

• Record Type: Journal Article
• Authors: Nguyen, Dieu D.
• Editors: Valluri, Monica; Sellwood, J. A.
• Is Part Of: Proceedings of the International Astronomical Union. Volume 14:Issue S353(2019)
• Page Start: 286
• Page End: 288
• Publication Date: 2019-06
• Subjects: intermediate mass black holes, -- stellar dynamics, -- early-type galaxies; Astronomy -- Congresses; Astronomy -- Periodicals; 520
• DOI: 10.1017/S1743921319009001
• Languages: English
• ISSNs: 1743-9213

Abstract

Abstract: The existence intermediate mass black holes (IMBH, M BH ≲ 10 6 M ⊙ ) at the centers low-mass galaxies with stellar masses between (1–10)×10 M ⊙ are key to constraining the origin of black hole (BH) seeds and understanding the physics deriving the co-evolution of central BHs and their host galaxies. However, finding and weighing IMBH is challenging. Here, we present the first observational evidence for such IMBHs at the centers of the five nearest early-type galaxies (D < 3.5 Mpc, ETGs) revealed by adaptive optics kinematics from Gemini and VLT and high-resolution HST spectroscopy. We find that all five galaxies appear to host IMBHs with four of the five having masses below 1 million M ⊙ and the lowest mass BH being only ∼7, 000 M ⊙ . This work provides a first glimpse of the demographics of IMBHs in this galaxy mass range and at velocity dispersions < 70 km/s, and thus provides an important extension to the bulge mass and galaxy dispersion scaling relations. The ubiquity of central BHs in these galaxies provides a unique constraint on BH seed formation scenarios, favoring a formation mechanism that produces an abundance of low-mass seed BHs.