A Normal Supermassive Black Hole in NGC 1277

Journal
Date Issued
2016
Author(s)
Graham, Alister W.
•
Durré, Mark
•
Savorgnan, Giulia A. D.
•
Medling, Anne M.
•
Batcheldor, Dan
•
Scott, Nicholas
•
Watson, Beverly
•
DOI
Abstract
The identification of galaxies with “overly massive” black holes requires two measurements: a black hole mass (Mbh) and a host spheroid mass ({M}{{sph,\ast }}). Here we provide our measurements for NGC 1277. Our structural decomposition reveals that NGC 1277 is dominated by a “classical” spheroid with a Sérsic index n = 5.3, a half-light radius {R}{{e,major}}=2.1 {{kpc}}, and a stellar mass of 2.7× {10}11\quad {M}☉ (using {M}*/{L}V=11.65, Martín-Navarro et al.). This mass is an order of magnitude greater than originally reported. Using the latest Mbh-n, Mbh-{M}{{sph,\ast }}, and Mbh-σ relations, the expected black hole mass is, respectively, ({0.57}-0.40+1.29)× {10}9\quad {M}☉ , ({1.58}-1.13+4.04)× {10}9\quad {M}☉ , and ({2.27}-1.44+4.04)× {10}9\quad {M}☉ (using σ = 300 km s-1) for which the “sphere-of-influence” is 0.″31. Our new kinematical maps obtained from laser guide star assisted, adaptive optics on the Keck I Telescope dramatically reaffirm the presence of the inner, nearly edge-on, disk seen in the galaxy image. We also report that this produces a large velocity shear (∼400 km s-1) across the inner 0.″2 (70 pc) plus elevated values of \sqrt{{σ }2+{V}2} across the inner (+/- 3\buildrel{\prime\prime}\over{.} 8)× (+/- 0\buildrel{\prime\prime}\over{.} 6) region of the galaxy. Our new multi-Gaussian expansion (MGE) models and Jeans Anisotropic MGE analysis struggled to match this extended component. Our optimal black hole mass, albeit a probable upper limit because of the disk is 1.2 × 109 M☉ (M/{L}V=12.3). This is an order of magnitude smaller than originally reported and 4 times smaller than recently reported. It gives an {M}{{bh}}/{M}{{sph,\ast }} ratio of 0.45% in agreement with the median (≈0.5%) and range (0.1%-5.0%) observed in non-dwarf, early-type galaxies. This result highlights the need for caution with inner disks.
Volume
819
Issue
1
Start page
43
Uri
Url
Issn Identifier
0004-637X
Ads BibCode
2016ApJ...819...43G
Rights
open.access
File(s)
Loading...
Thumbnail Image
Name

Graham_2016_ApJ_819_43.pdf

Description
PDF editoriale
Size

3.45 MB

Format

Adobe PDF

Checksum (MD5)

727106fe94f96fdc7ff0ba2efac974d7