Molecular Gas and Radio Jet Interaction: a Case Study of the Seyfert 2 AGN M51

We observed multiple CO transition lines and the HCN(1-0) line at ∼ 1′′ (∼ 34 pc) or higher resolution toward the Seyfert 2 nucleus of M51 using the IRAM Plateau de Bure Interferometer (PdBI) and the Submillimeter Array (SMA). All the images show very similar overall molecular gas distribution; there are two discrete clouds at the eastern and western sides of the nucleus, and the western cloud exhibits an elongated distribution and velocity gradient along the radio jet. In addition, high HCN(1-0)/CO(1-0) brightness temperature ratios of about unity have been observed, especially along the radio jet, similar to those observed in shocked molecular gas in our Galaxy. This strongly indicates that the molecular gas along the jet is shocked, that the radio jet and the molecular gas are interacting, and the jet is entraining both diffuse (CO) and dense (HCN) molecular gas outwards from the circumnuclear region. This is the first clear imaging of the outflowing molecular gas entrained by the AGN jet, and showing the detailed physical status of outflowing molecular gas. Since a relatively high HCN(1-0)/CO(1-0) ratio has been observed in the high velocity wing of ultraluminous infrared galaxies, it can also be explained by a similar mechanism to those we describe here.

[1]  Astrophysics,et al.  RESOLVING THE BRIGHT HCN(1−0) EMISSION TOWARD THE SEYFERT 2 NUCLEUS OF M51: SHOCK ENHANCEMENT BY RADIO JETS AND WEAK MASING BY INFRARED PUMPING? , 2014, 1410.7863.

[2]  A. Fuente,et al.  Molecular line emission in NGC 1068 imaged with ALMA - II. The chemistry of the dense molecular gas , 2014, 1407.4940.

[3]  A. Fuente,et al.  Molecular line emission in NGC 1068 imaged with ALMA: I. An AGN-driven outflow in the dense molecular gas , 2014, 1405.7706.

[4]  R. Neri,et al.  ALMA observations of feeding and feedback in nearby Seyfert galaxies: an AGN-driven outflow in NGC 1433 (Corrigendum) , 2013, 1309.7486.

[5]  D. Meier,et al.  ALMA FOLLOWS STREAMING OF DENSE GAS DOWN TO 40 pc FROM THE SUPERMASSIVE BLACK HOLE IN NGC 1097 , 2013, 1304.6722.

[6]  S. García-Burillo,et al.  Physical properties of dense molecular gas in centres of Seyfert galaxies , 2012, 1205.4242.

[7]  R. Neri,et al.  Detection of HCN, HCO+, and HNC in the Mrk 231 molecular outflow. Dense molecular gas in the AGN wind , 2011, 1111.6762.

[8]  R. Neri,et al.  SUBMILLIMETER ARRAY/PLATEAU DE BURE INTERFEROMETER MULTIPLE LINE OBSERVATIONS OF THE NEARBY SEYFERT 2 GALAXY NGC 1068: SHOCK-RELATED GAS KINEMATICS AND HEATING IN THE CENTRAL 100 pc? , 2011, 1105.6089.

[9]  D. Iono,et al.  DISENTANGLING THE CIRCUMNUCLEAR ENVIRONS OF CENTAURUS A. II. ON THE NATURE OF THE BROAD ABSORPTION LINE , 2010, 1007.2061.

[10]  R. Genzel,et al.  STELLAR AND MOLECULAR GAS KINEMATICS OF NGC 1097: INFLOW DRIVEN BY A NUCLEAR SPIRAL , 2009, 0903.0313.

[11]  D. Iono,et al.  DISENTANGLING THE CIRCUMNUCLEAR ENVIRONS OF CENTAURUS A. I. HIGH-RESOLUTION MOLECULAR GAS IMAGING , 2009, 0901.1656.

[12]  R. Genzel,et al.  MOLECULAR GAS STREAMERS FEEDING AND OBSCURING THE ACTIVE NUCLEUS OF NGC 1068 , 2008, 0809.4943.

[13]  K. Kohno,et al.  Interferometric 12CO J = 2-1 Image of the Nuclear Region of Seyfert 1 Galaxy NGC 1097 , 2008, 0805.3648.

[14]  D. Iono,et al.  Tracing star formation in galaxies with molecular line and continuum observations , 2008, 0805.1801.

[15]  Kotaro Kohno,et al.  Dense gas in normal and active galaxies , 2008 .

[16]  S. Muller,et al.  The Circumnuclear Molecular Gas in the Seyfert Galaxy NGC 4945 , 2007, 0709.3960.

[17]  S. Muller,et al.  Jet-disturbed molecular gas near the Seyfert 2 nucleus in M 51 , 2007, 0704.0947.

[18]  R. Neri,et al.  Molecular gas in NUclei of GAlaxies (NUGA) - VI. Detection of a molecular gas disk/torus via HCN in the Seyfert 2 galaxy NGC 6951? , 2007, astro-ph/0701403.

[19]  J. Vinkó,et al.  Distance estimate and progenitor characteristics of SN 2005cs in M51 , 2006, astro-ph/0608430.

[20]  D. Iono,et al.  Submillimeter Array 12CO (J = 3-2) Interferometric Observations of the Central Region of M51 , 2004, astro-ph/0407643.

[21]  L. Bradley,et al.  Physical Conditions in the Narrow-Line Region of M51 , 2003, astro-ph/0312067.

[22]  T. Mahoney,et al.  Dense Molecular Gas and Star Formation in Nearby Seyfert Galaxies , 2002 .

[23]  K. Menten,et al.  Water Maser Emission from the Active Nucleus in M51 , 2001, astro-ph/0109154.

[24]  M. Wright,et al.  A Multiline Aperture Synthesis Study of Orion-KL , 1996 .

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

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

[27]  T. Umemoto,et al.  The outflow in the L1157 dark cloud : evidence for shock heating of the interacting gas , 1992 .

[28]  P. Crane,et al.  THE RADIO JET IN M51 , 1992 .

[29]  J. Miller,et al.  Spectropolarimetry and the nature of NGC 1068 , 1985 .