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Title: THE NGC 404 NUCLEUS: STAR CLUSTER AND POSSIBLE INTERMEDIATE-MASS BLACK HOLE

Abstract

We examine the nuclear morphology, kinematics, and stellar populations in nearby S0 galaxy NGC 404 using a combination of adaptive optics assisted near-IR integral-field spectroscopy, optical spectroscopy, and Hubble Space Telescope imaging. These observations enable study of the NGC 404 nucleus at a level of detail possible only in the nearest galaxies. The surface brightness profile suggests the presence of three components: a bulge, a nuclear star cluster (NSC), and a central light excess within the cluster at radii < 3 pc. These components have distinct kinematics with modest rotation seen in the NSC and counter-rotation seen in the central excess. Molecular hydrogen emission traces a disk with rotation nearly orthogonal to that of the stars. The stellar populations of the three components are also distinct, with half of the mass of the NSC having ages of {approx}1 Gyr (perhaps resulting from a galaxy merger), while the bulge is dominated by much older stars. Dynamical modeling of the stellar kinematics gives a total NSC mass of 1.1 x 10{sup 7} M{sub sun}. Dynamical detection of a possible intermediate-mass black hole (BH) is hindered by uncertainties in the central stellar mass profile. Assuming a constant mass-to-light ratio, the stellar dynamical modelingmore » suggests a BH mass of <1 x 10{sup 5} M{sub sun}, while the molecular hydrogen gas kinematics are best fitted by a BH with a mass of 4.5{sup +3.5}{sub -2.0} x 10{sup 5} M{sub sun}. Unresolved and possibly variable dust emission in the near-infrared and active galactic nucleus-like molecular hydrogen emission-line ratios do suggest the presence of an accreting BH in this nearby LINER galaxy.« less

Authors:
;  [1];  [2];  [3];  [4]; ;  [5];  [6]; ;  [7];  [8]
  1. Harvard-Smithsonian Center for Astrophysics, 60 Garden Street Cambridge, MA 02138 (United States)
  2. Sub-department of Astrophysics, University of Oxford, Denys Wilkinson Building, Keble Road, Oxford, OX1 3RH (United Kingdom)
  3. European Southern Observatory, Karl-Schwarzschild-Str. 2, 85748 Garching (Germany)
  4. Institute of Astronomy, University of Cambridge, Madingley Road, Cambridge CB3 0HA (United Kingdom)
  5. National Optical Astronomy Observatory, 950 North Cherry Ave., Tucson, AZ 85719 (United States)
  6. Jeremiah Horrocks Institute, University of Central Lancashire, Preston, Lancashire, PR1 2HE (United Kingdom)
  7. Gemini Observatory, 670 N. A'ohoku Place Hilo, HI 96720 (United States)
  8. Herzberg Institute of Astrophysics, 5071 West Saanich Road, Victoria, BC V9E 2E7 (Canada)
Publication Date:
OSTI Identifier:
21448885
Resource Type:
Journal Article
Journal Name:
Astrophysical Journal
Additional Journal Information:
Journal Volume: 714; Journal Issue: 1; Other Information: DOI: 10.1088/0004-637X/714/1/713; Journal ID: ISSN 0004-637X
Country of Publication:
United States
Language:
English
Subject:
79 ASTROPHYSICS, COSMOLOGY AND ASTRONOMY; BLACK HOLES; DUSTS; GALAXIES; GALAXY NUCLEI; HYDROGEN; MASS; ROTATION; SIMULATION; SPECTROSCOPY; STAR CLUSTERS; STARS; TELESCOPES; ELEMENTS; MOTION; NONMETALS

Citation Formats

Seth, Anil C, Caldwell, Nelson, Cappellari, Michele, Neumayer, Nadine, Bastian, Nate, Olsen, Knut, Blum, Robert D, Debattista, Victor P, McDermid, Richard, Stephens, Andrew, and Puzia, Thomas. THE NGC 404 NUCLEUS: STAR CLUSTER AND POSSIBLE INTERMEDIATE-MASS BLACK HOLE. United States: N. p., 2010. Web. doi:10.1088/0004-637X/714/1/713.
Seth, Anil C, Caldwell, Nelson, Cappellari, Michele, Neumayer, Nadine, Bastian, Nate, Olsen, Knut, Blum, Robert D, Debattista, Victor P, McDermid, Richard, Stephens, Andrew, & Puzia, Thomas. THE NGC 404 NUCLEUS: STAR CLUSTER AND POSSIBLE INTERMEDIATE-MASS BLACK HOLE. United States. doi:10.1088/0004-637X/714/1/713.
Seth, Anil C, Caldwell, Nelson, Cappellari, Michele, Neumayer, Nadine, Bastian, Nate, Olsen, Knut, Blum, Robert D, Debattista, Victor P, McDermid, Richard, Stephens, Andrew, and Puzia, Thomas. Sat . "THE NGC 404 NUCLEUS: STAR CLUSTER AND POSSIBLE INTERMEDIATE-MASS BLACK HOLE". United States. doi:10.1088/0004-637X/714/1/713.
@article{osti_21448885,
title = {THE NGC 404 NUCLEUS: STAR CLUSTER AND POSSIBLE INTERMEDIATE-MASS BLACK HOLE},
author = {Seth, Anil C and Caldwell, Nelson and Cappellari, Michele and Neumayer, Nadine and Bastian, Nate and Olsen, Knut and Blum, Robert D and Debattista, Victor P and McDermid, Richard and Stephens, Andrew and Puzia, Thomas},
abstractNote = {We examine the nuclear morphology, kinematics, and stellar populations in nearby S0 galaxy NGC 404 using a combination of adaptive optics assisted near-IR integral-field spectroscopy, optical spectroscopy, and Hubble Space Telescope imaging. These observations enable study of the NGC 404 nucleus at a level of detail possible only in the nearest galaxies. The surface brightness profile suggests the presence of three components: a bulge, a nuclear star cluster (NSC), and a central light excess within the cluster at radii < 3 pc. These components have distinct kinematics with modest rotation seen in the NSC and counter-rotation seen in the central excess. Molecular hydrogen emission traces a disk with rotation nearly orthogonal to that of the stars. The stellar populations of the three components are also distinct, with half of the mass of the NSC having ages of {approx}1 Gyr (perhaps resulting from a galaxy merger), while the bulge is dominated by much older stars. Dynamical modeling of the stellar kinematics gives a total NSC mass of 1.1 x 10{sup 7} M{sub sun}. Dynamical detection of a possible intermediate-mass black hole (BH) is hindered by uncertainties in the central stellar mass profile. Assuming a constant mass-to-light ratio, the stellar dynamical modeling suggests a BH mass of <1 x 10{sup 5} M{sub sun}, while the molecular hydrogen gas kinematics are best fitted by a BH with a mass of 4.5{sup +3.5}{sub -2.0} x 10{sup 5} M{sub sun}. Unresolved and possibly variable dust emission in the near-infrared and active galactic nucleus-like molecular hydrogen emission-line ratios do suggest the presence of an accreting BH in this nearby LINER galaxy.},
doi = {10.1088/0004-637X/714/1/713},
journal = {Astrophysical Journal},
issn = {0004-637X},
number = 1,
volume = 714,
place = {United States},
year = {2010},
month = {5}
}