VERY LARGE ARRAY LIMITS FOR INTERMEDIATE-MASS BLACK HOLES IN THREE GLOBULAR CLUSTERS

The observational evidence for central black holes in globular clusters has been argued extensively, and their existence has important consequences for both the formation and evolution of the cluster. Most of the evidence comes from dynamical arguments, but the interpretation is difficult, given the short relaxation times and old ages of the clusters. One of the most robust signatures for the existence of a BH is radio and/or X-ray emission. We observed three globular clusters: NGC6093 (M80), NGC6266 (M62), and NGC7078 (M15), with the Very Large Array (VLA) in the A and C configuration with a 3-σ noise of 36, 36, and 25 μJy, respectively. We find no statistically significant evidence for radio emission from the central region for any of the three clusters. NGC6266 shows a 2-σ detection. It is difficult to infer a mass from these upper limits due to uncertainty about the central gas density, accretion rate, and accretion model.

[1]  Luis C. Ho,et al.  Radio Emission from the Intermediate-Mass Black Hole in the Globular Cluster G1 , 2007, 0704.1458.

[2]  David Pooley,et al.  X-Rays from the Globular Cluster G1: Intermediate-Mass Black Hole or Low-Mass X-Ray Binary? , 2006, astro-ph/0605049.

[3]  K. Gebhardt,et al.  Surface Brightness Profiles of Galactic Globular Clusters from Hubble Space Telescope Images , 2006, astro-ph/0604251.

[4]  L. Ho,et al.  An Intermediate-Mass Black Hole in the Globular Cluster G1: Improved Significance from New Keck and Hubble Space Telescope Observations , 2005, astro-ph/0508251.

[5]  P. Hopkins,et al.  The Evolution of the MBH-σ Relation , 2005, astro-ph/0506038.

[6]  L. Ho,et al.  Dwarf Seyfert 1 Nuclei and the Low-Mass End of the MBH-σ Relation , 2004, astro-ph/0412575.

[7]  T. Maccarone,et al.  Finding Faint Intermediate-Mass Black Holes in the Radio Band , 2004, astro-ph/0412014.

[8]  T. Maccarone.  Radio emission as a test of the existence of intermediate‐mass black holes in globular clusters and dwarf spheroidal galaxies , 2004, astro-ph/0403530.

[9]  W. Priedhorsky,et al.  M31 Globular Cluster X-Ray Sources: XMM-Newton and Chandra Results , 2004, astro-ph/0402619.

[10]  M. Colpi,et al.  Probing the Presence of a Single or Binary Black Hole in the Globular Cluster NGC 6752 with Pulsar Dynamics , 2003, astro-ph/0309017.

[11]  T. D. Matteo,et al.  A Fundamental plane of black hole activity , 2003, astro-ph/0305261.

[12]  Matthew Bierbaum,et al.  Formation of Massive Black Holes in Dense Star Clusters. I. Mass Segregation and Core Collapse , 2003, astro-ph/0308449.

[13]  P. Hut,et al.  A Dynamical Model for the Globular Cluster G1 , 2003, astro-ph/0301469.

[14]  J. Makino,et al.  On the Central Structure of M15 , 2002, astro-ph/0210133.

[15]  Puragra Guhathakurta,et al.  Hubble Space Telescope Evidence for an Intermediate-Mass Black Hole in the Globular Cluster M15. I. STIS Spectroscopy and WFPC2 Photometry , 2002, astro-ph/0209314.

[16]  Simon F. Portegies Zwart,et al.  The Runaway Growth of Intermediate-Mass Black Holes in Dense Star Clusters , 2002, astro-ph/0201055.

[17]  M. Miller,et al.  Production of intermediate-mass black holes in globular clusters , 2001, astro-ph/0106188.

[18]  F. Camilo,et al.  Detection of Ionized Gas in the Globular Cluster 47 Tucanae , 2001, astro-ph/0107206.

[19]  USRA,et al.  Chandra Limits on X-Ray Emission Associated with the Supermassive Black Holes in Three Giant Elliptical Galaxies , 2001, astro-ph/0106326.

[20]  Toshikazu Ebisuzaki,et al.  UvA-DARE ( Digital Academic Repository ) Missing Link Found ? The " Runaway " Path to Supermassive Black Holes , 2001 .

[21]  G. Kauffmann,et al.  The Correlation between black hole mass and bulge velocity dispersion in hierarchical galaxy formation models , 2000, astro-ph/0007369.

[22]  Ralf Bender,et al.  A Relationship between Nuclear Black Hole Mass and Galaxy Velocity Dispersion , 2000, astro-ph/0006289.

[23]  D. Merritt,et al.  A Fundamental Relation between Supermassive Black Holes and Their Host Galaxies , 2000, astro-ph/0006053.

[24]  W. Goss,et al.  Deep VLA Images of Globular Clusters , 1991 .

[25]  G. Illingworth,et al.  Dynamical models for M15 without a black hole , 1977 .

[26]  J. Norris,et al.  Evidence for a Central Massive Object in the X-Ray Cluster M15 , 1976 .