SIGNATURE OF AN INTERMEDIATE-MASS BLACK HOLE IN THE CENTRAL MOLECULAR ZONE OF OUR GALAXY

We mapped the high-velocity compact cloud CO-0.40-0.22 in 21 molecular lines in the 3 mm band using the Nobeyama Radio Observatory 45 m radio telescope. Eighteen lines were detected from CO-0.40-0.22. The map of each detected line shows that this cloud has a compact appearance (d=~3 pc) and extremely broad velocity width (DV=~100 km/s). The mass and kinetic energy of CO-0.40-0.22 are estimated to be 10^{3.6} M_sun and 10^{49.7} erg, respectively. The representative position-velocity map along the major axis shows that CO-0.40-0.22 consists of an intense region with a shallow velocity gradient and a less intense high-velocity wing. Here, we show that this kinematical structure can be attributed to a gravitational kick to the molecular cloud caused by an invisible compact object with a mass of ~10^5 M_sun. Its compactness and the absence of counterparts at other wavelengths suggest that this massive object is an intermediate-mass black hole.

[1]  R. V. D. Bosch,et al.  The Dynamical Mass-to-Light Ratio Profile and Distance of the Globular Cluster M15 , 2005, astro-ph/0512503.

[2]  T. Okajima,et al.  A Stellar-Mass Black Hole in the Ultraluminous X-Ray Source M82 X-1? , 2006, astro-ph/0610430.

[3]  A. Miyazaki,et al.  A Hyperenergetic CO Shell in the Galactic Center Molecular Cloud Complex , 2001 .

[4]  K. Kamegai,et al.  A NEW LOOK AT THE GALACTIC CIRCUMNUCLEAR DISK , 2011 .

[5]  N. Gehrels,et al.  FIRST EVIDENCE FOR SPECTRAL STATE TRANSITIONS IN THE ESO 243-49 HYPERLUMINOUS X-RAY SOURCE HLX-1 , 2009, 0909.4458.

[6]  U. Cambridge,et al.  Weighing the black holes in ultraluminous X‐ray sources through timing , 2008, 0804.3378.

[7]  J. M. Miller,et al.  X-Ray Spectroscopic Evidence for Intermediate-Mass Black Holes: Cool Accretion Disks in Two Ultraluminous X-Ray Sources , 2003 .

[8]  C. Brogan,et al.  Low-mass black holes as the remnants of primordial black hole formation , 2012, Nature Communications.

[9]  A. R. Rivolo,et al.  Mass, luminosity, and line width relations of Galactic molecular clouds , 1987 .

[10]  J. Whiteoak,et al.  A catalogue of Hα-emission regions in the southern Milky Way , 1960 .

[11]  M. Kamionkowski,et al.  X-rays from isolated black holes in the Milky Way , 2001, astro-ph/0109539.

[12]  S. L. Shapiro,et al.  Star clusters containing massive, central black holes. III - Evolution calculations , 1979 .

[13]  K. Kamegai,et al.  ASTE CO J = 3–2 SURVEY OF THE GALACTIC CENTER , 2012 .

[14]  K. Kamegai,et al.  A Large Expanding Molecular Arc in the Sagittarius B1 Complex , 2009 .

[15]  A. Miyazaki,et al.  A Large-Scale CO Survey of the Galactic Center , 1998 .

[16]  K. Gebhardt,et al.  The Dynamical M/l-profile and Distance of the Globular Cluster M15 , 2005 .

[17]  A. Miyazaki,et al.  Aperture Synthesis Imaging of a High-Velocity Compact Cloud near the Galactic Center , 2008 .

[18]  S. Djorgovski,et al.  Surface photometry in cores of globular clusters , 1984 .

[19]  A. Brandenburg,et al.  SHEAR-DRIVEN INSTABILITIES IN HALL-MAGNETOHYDRODYNAMIC PLASMAS , 2010, 1012.5284.

[20]  Karl Gebhardt,et al.  Gemini and Hubble Space Telescope Evidence for an Intermediate-Mass Black Hole in ω Centauri , 2008 .

[21]  A. Miyazaki,et al.  A High-Velocity Molecular Cloud near the Center of the Galaxy , 1998, astro-ph/9810434.

[22]  L. Chomiuk,et al.  NO EVIDENCE FOR INTERMEDIATE-MASS BLACK HOLES IN GLOBULAR CLUSTERS: STRONG CONSTRAINTS FROM THE JVLA , 2012, 1203.6352.

[23]  F. Bauer,et al.  A Chandra Catalog of X-Ray Sources in the Central 150 pc of the Galaxy , 2006, astro-ph/0601627.

[24]  Aya Kubota,et al.  Accretion Disk Spectra of Ultraluminous X-Ray Sources in Nearby Spiral Galaxies and Galactic Superluminal Jet Sources , 2003 .

[25]  M. Seta,et al.  KINEMATICS OF SHOCKED MOLECULAR GAS ADJACENT TO THE SUPERNOVA REMNANT W44 , 2013, 1307.6276.

[26]  I. Chilingarian,et al.  A supermassive black hole in an ultra-compact dwarf galaxy , 2014, Nature.

[27]  Giuseppina Fabbiano,et al.  Populations of X-Ray Sources in Galaxies , 2006 .

[28]  I. Mirabel,et al.  A catalogue of ultraluminous X-ray sources in external galaxies , 2005 .

[29]  K. Kamegai,et al.  HIGH VELOCITY COMPACT CLOUDS IN THE SAGITTARIUS C REGION , 2014, 1402.1335.

[30]  Makoto Nagai,et al.  A CO J = 3–2 Survey of the Galactic Center , 2007 .

[31]  Makoto Nagai,et al.  HIGH RESOLUTION MAPPINGS OF THE L = 1.3 ◦ COMPLEX IN MOLECULAR LINES : DISCOVERY OF A PROTO-SUPERBUBBLE , 2007 .

[32]  Eugene Serabyn,et al.  THE GALACTIC CENTER ENVIRONMENT , 1996 .

[33]  Y. Yamamoto,et al.  AKARI-CAS—Online Service for AKARI All-Sky Catalogues , 2011 .

[34]  R. Genzel,et al.  MONITORING STELLAR ORBITS AROUND THE MASSIVE BLACK HOLE IN THE GALACTIC CENTER , 2008, 0810.4674.

[35]  Jessica R. Lu,et al.  Measuring Distance and Properties of the Milky Way’s Central Supermassive Black Hole with Stellar Orbits , 2008, 0808.2870.

[36]  L. Ho,et al.  Coevolution (Or Not) of Supermassive Black Holes and Host Galaxies: Supplemental Material , 2013, 1304.7762.

[37]  Puragra Guhathakurta,et al.  Hubble Space Telescope Evidence for an Intermediate-Mass Black Hole in the Globular Cluster M15. II. Kinematic Analysis and Dynamical Modeling , 2002, astro-ph/0209315.

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

[39]  T. P. Roberts,et al.  X-ray observations of ultraluminous X-ray sources , 2007, 0706.2562.