Enhanced HCN (1-0) Emission in the Type-1 Seyfert Galaxy NGC 1097

The central kpc region of the low-luminosity type-1 Seyfert galaxy NGC 1097 has been observed in the CO (1–0) and HCN (1–0) lines with the Nobeyama Millimeter Array and the NRO 45m telescope. We have found a striking enhancement of the HCN emission toward the active nucleus of NGC 1097; a large fraction of the CO emission comes from a circumnuclear starburst ring (r ∼ 10 �� or 700pc at D =1 4.5Mpc), whereas the HCN emission is dominated by a strong unresolved peak at the nucleus. The HCN-to-CO integrated intensity ratio on the brightness temperature scale, RHCN/CO, is about 0.11 in the aperture of the 45 m telescope beams (15 �� for CO and 19 �� for HCN), but reaches 0.34 in the smaller aperture (10 �� ×4. 4). These CO and HCN properties in NGC 1097 are similar

[1]  A. Tielens.  The Physics and Chemistry of the Interstellar Medium , 2005 .

[2]  K. Kohno,et al.  Diffuse and Gravitationally Stable Molecular Gas in the Post-Starburst Galaxy NGC 5195 , 2002, astro-ph/0206400.

[3]  N. Kuno,et al.  Radial Distributions of the HCN/CO Ratio in Nearby CO Bright Galaxies , 2002 .

[4]  J. Reunanen,et al.  Near-infrared spectroscopy of nearby Seyfert galaxies — I. First results , 2001, astro-ph/0111463.

[5]  M. Imanishi.  3-4 Micron Spectroscopy of Seyfert 2 Nuclei to Quantitatively Assess the Energetic Importance of Compact Nuclear Starbursts , 2001, astro-ph/0112299.

[6]  H. Awaki,et al.  Estimation of Central Black Hole Masses in Low-Luminosity Active Galactic Nuclei , 2001 .

[7]  D. Hartmann,et al.  The Milky Way in Molecular Clouds: A New Complete CO Survey , 2000, astro-ph/0009217.

[8]  L. Ho,et al.  CENTRAL KILOPARSEC OF STARBURSTS AND AGN: THE LA PALMA CONNECTION , 2001 .

[9]  A. Eckart,et al.  Distribution and Kinematics of the Circumnuclear Molecular Gas in the Seyfert 1 Galaxy NGC 3227 , 2000 .

[10]  Noriyuki Kawaguchi,et al.  1-GHz Bandwidth Digital Spectro-Correlator System for the Nobeyama Millimeter Array , 2000 .

[11]  R. Booth,et al.  Dense molecular gas in Seyfert galaxies , 2000 .

[12]  A.Eckart,et al.  Distribution and Kinematics of the Circum-nuclear Molecular Gas in the Seyfert 1 Galaxy NGC 3227 , 1999, astro-ph/9911487.

[13]  D. Sokoloff,et al.  Magnetic field as a tracer of sheared gas flow in barred galaxies , 1999, Nature.

[14]  Y. Taniguchi,et al.  CO Survey of a Distance-limited Seyfert Sample. I. The Data , 1998 .

[15]  K. Kohno,et al.  Dense Molecular Gas Associated with the Circumnuclear Star-forming Ring in the Barred Spiral Galaxy NGC 6951 , 1998, astro-ph/9808229.

[16]  C. Leitherer,et al.  Ultraviolet-Optical Observations of the Seyfert 2 Galaxies NGC 7130, NGC 5135, and IC 3639: Implications for the Starburst-Active Galactic Nucleus Connection , 1998, astro-ph/9806107.

[17]  E. Seaquist,et al.  Physical Conditions of the Molecular Gas in Seyfert Galaxies , 1998 .

[18]  G. Rieke,et al.  Molecular Gas, Morphology, and Seyfert Galaxy Activity , 1997 .

[19]  Dayton L. Jones,et al.  The Nature of the Optical Jets in the Spiral Galaxy NGC 1097 , 1997 .

[20]  C. Leitherer,et al.  A Powerful Nuclear Starburst in the Seyfert Galaxy Markarian 477: Implications for the Starburst-Active Galactic Nucleus Connection , 1997 .

[21]  A. V. Filippenko,et al.  Evidence for a Precessing Accretion Disk in the Nucleus of NGC 1097 , 1997, astro-ph/9705176.

[22]  L. Blitz,et al.  Synthesis Imaging of Dense Gas in Nearby Galaxies , 1996, astro-ph/9610103.

[23]  L. Colina,et al.  X-Ray Emission of Active Galactic Nuclei with Circumnuclear Star-forming Rings: NGC 1097 and NGC 7469 , 1996 .

[24]  K. Kohno,et al.  Aperture Synthesis CO and HCN Observations of M51: Dense Molecular Disk around a Low-Luminosity Active Galactic Nucleus , 1996 .

[25]  K. Makishima,et al.  Detection of Excess Hard X-Ray Emission from the Optical Jet Galaxy NGC 1097 , 1996 .

[26]  J. Baldwin,et al.  Nuclear rings in active galaxies , 1996 .

[27]  Timothy A. D. Paglione,et al.  The Distribution of the Dense Clouds in the Starburst Nucleus of NGC 253 , 1995 .

[28]  George H. Rieke,et al.  Low-luminosity and obscured seyfert nuclei in nearby galaxies , 1995 .

[29]  L. Blitz,et al.  High-Resolution Berkeley-Illinois-Maryland Association Observations of CO, HCN, and 13CO in NGC 1068 , 1995 .

[30]  L. Ho,et al.  Hubble Space Telescope Observations of Circumnuclear Star-Forming Rings in NGC 1097 and NGC 6951 , 1995 .

[31]  D. Terndrup,et al.  Multiband Images of the Barred Galaxy NGC 1097 , 1995, astro-ph/9503067.

[32]  R. Terlevich,et al.  The origin of the blue continuum in type 2 Seyferts: reflection or star-forming tori? , 1995 .

[33]  Leo Blitz,et al.  Dense gas in the bulges of external galaxies , 1993 .

[34]  R. Genzel,et al.  The Nature of the dense obscuring material in the nucleus of NGC 1068 , 1993 .

[35]  J. Jackson,et al.  Dense molecular gas toward the nucleus of the Seyfert galaxy NGC 1068 , 1993 .

[36]  C. Telesco,et al.  The genesis of starbursts and infrared emission in the centers of galaxies , 1993 .

[37]  Robert Antonucci,et al.  Unified models for active galactic nuclei and quasars , 1993 .

[38]  N. Scoville,et al.  Twin peaks of CO emission in the central regions of barred galaxies , 1992 .

[39]  Simon J. E. Radford,et al.  Dense Molecular Gas and Starbursts in Ultraluminous Galaxies , 1992 .

[40]  J. Hulst,et al.  H I in Barred Spiral Galaxies. I. NGC 1365 , 1989 .

[41]  C. Viau,et al.  Aviation gasoline: comparative subchronic nephrotoxicity study in the male rat. , 1988, Toxicology letters.

[42]  R. Tully.  Nearby Galaxies Catalog , 1988 .