A1 Refereed original research article in a scientific journal
The black hole-bulge mass relation in the megamaser host galaxies
Authors: Ronald Läsker, Jenny E. Greene, Anil Seth, Glenn van de Ven, James A. Braatz, Christian Henkel, K. Y. Lo
Publisher: IOP PUBLISHING LTD
Publication year: 2016
Journal: Astrophysical Journal
Journal name in source: ASTROPHYSICAL JOURNAL
Journal acronym: ASTROPHYS J
Article number: 3
Volume: 825
Issue: 1
Number of pages: 40
ISSN: 0004-637X
eISSN: 1538-4357
DOI: https://doi.org/10.3847/0004-637X/825/1/3
Abstract
We present Hubble Space Telescope (HST) images for nine megamaser disk galaxies with the primary goal of studying photometric BH-galaxy scaling relations. The megamaser disks provide the highest-precision extragalactic BH mass measurements, while our high-resolution HST imaging affords us the opportunity to decompose the complex nuclei of their late-type hosts in detail. Based on the morphologies and shapes of the galaxy nuclei, we argue that most of these galaxies' central regions contain secularly evolving components (pseudo-bulges), and in many cases we photometrically identify co-existing "classical" bulge components as well. Using these decompositions, we draw the following conclusions. (1) The megamaser BH masses span two orders of magnitude (10(6) - 10(8) M-circle dot) while the stellar mass of their spiral host galaxies are all similar to 10(11)M(circle dot) within a factor of three. (2) The BH masses at a given bulge mass or total stellar mass in the megamaser host spiral galaxies tend to be lower than expected when compared to an extrapolation of the BH-bulge relation based on early-type galaxies. (3) The observed large intrinsic scatter of BH masses in the megamaser host galaxies raises the question of whether scaling relations exist in spiral galaxies.
We present Hubble Space Telescope (HST) images for nine megamaser disk galaxies with the primary goal of studying photometric BH-galaxy scaling relations. The megamaser disks provide the highest-precision extragalactic BH mass measurements, while our high-resolution HST imaging affords us the opportunity to decompose the complex nuclei of their late-type hosts in detail. Based on the morphologies and shapes of the galaxy nuclei, we argue that most of these galaxies' central regions contain secularly evolving components (pseudo-bulges), and in many cases we photometrically identify co-existing "classical" bulge components as well. Using these decompositions, we draw the following conclusions. (1) The megamaser BH masses span two orders of magnitude (10(6) - 10(8) M-circle dot) while the stellar mass of their spiral host galaxies are all similar to 10(11)M(circle dot) within a factor of three. (2) The BH masses at a given bulge mass or total stellar mass in the megamaser host spiral galaxies tend to be lower than expected when compared to an extrapolation of the BH-bulge relation based on early-type galaxies. (3) The observed large intrinsic scatter of BH masses in the megamaser host galaxies raises the question of whether scaling relations exist in spiral galaxies.
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