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MOLECULAR GAS AND RADIO JET INTERACTION: A CASE STUDY OF THE SEYFERT 2 AGN M51
MATSUSHITA, SATOKI,TRUNG, DINH-V,BOONE, FRDERIC,KRIPS, MELANIE,LIM, JEREMY,MULLER, SEBASTIEN The Korean Astronomical Society 2015 天文學論叢 Vol.30 No.2
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.
ASIAA EXTRAGALACTIC STUDY WITH THE SMA
MATSUSHITA SATOKI,MAO RUI-QING,MULLER SEBASTIEN,CHOU CHUEN- YI,SAWADA-SATOH SATOKO,TRUNG DINH-VAN,LIM JEREMY,HSIEH PEI-YING,PECK ALISON B. The Korean Astronomical Society 2005 Journal of The Korean Astronomical Society Vol.38 No.2
We present CO(3-2), CO(2-1), and 230 GHz (1.3 mm) continuum images of nearby galaxies taken with the Submillimeter Array (SMA). Our main topic is to study the relation between higher-J molecular gas (e.g., CO J=3-2, 2-1) and nuclear activities (e.g., active galactic nuclei [AGNs] and starbursts). The nearby Seyfert 2 galaxy M51 shows strong CO(3-2) emission from the circumnuclear molecular gas, with an intensity twice as strong as that of the CO(1-0) emission. Strong CO(3-2) emission enhancement suggests that the circum nuclear molecular gas in M51 is warm and dense, which may be related to the AGN activities. Molecular gas in the nearby moderate starburst galaxy NGC 6946 is distributed along the large-scale bar or spiral arms and along the minibar, and the multi-J CO line images show very similar distribution to each other. For this galaxy, there is no clear enhancement in higher-J lines as seen in M51, which may be because NGC 6946 does not have clear AGN activities. Based on the results of these two galaxies, the physical conditions of the circum nuclear molecular gas may be related to the AGN activities. We also observed the nearby edge-on starburst galaxy NGC 3628 and the starburst/Seyfert composite galaxy NGC 4945 with the CO(2-1) line and 230 GHz (1.3 mm) continuum emission. These information will give us some hints for understanding the relation between nuclear activities and circum nuclear molecular gas and dust.
THE GALACTIC-SCALE MOLECULAR OUTFLOWS IN STARBURST GALAXIES NGC 2146 AND NGC 3628
TSAI, AN-LI,MATSUSHITA, SATOKI The Korean Astronomical Society 2015 天文學論叢 Vol.30 No.2
Starburst galaxies have strong star formation activity and generate large scale outflows which eject a huge amount of gas mass. This process affects galaxy activity, and therefore, the detailed study of nearby starburst galaxies could provide valuable information for the study of distant ones. So far there have been only a few studies of galactic-scale molecular outflows due to the sensitivity limitation of telescopes. Our study provides two nearby examples, NGC 2146 and NGC 3628. We used Nobeyama Millimeter Array (NMA) CO(1-0) data, Chandra soft X-ray data, and NMA 3 mm data to study the kinematics of molecular outflows, their interaction with ionized outflows, and the star forming activity in the starburst region. We found that the gas ejected through molecular outflows is much more significant than that used to form stars.
Song, Yoogeun,Pu, Hung-Yi,Hirotani, Kouichi,Matsushita, Satoki,Kong, Albert K. H.,Chang, Hsiang-Kuang Oxford University Press 2017 Monthly notices of the Royal Astronomical Society. Vol.471 No.1
<P>We investigate the acceleration of electrons and positrons by magnetic-field-aligned electric fields in the polar funnel of an accreting black hole (BH). Applying the pulsar outer-gap theory to BH magnetospheres, we find that such a lepton accelerator arises in the immediate vicinity of the event horizon due to frame-dragging, and that their gamma-ray luminosity increases with decreasing accretion rate. Furthermore, we demonstrate that the gamma-ray flux is enhanced along the rotation axis by more than an order of magnitude if the BH spin increases from a = 0.90M to a = 0.9999M. As a result, if a ten-solar-mass, almost-maximally rotating BH is located within 3 kpc, when its accretion rate is between 0.005 and 0.01 per cent of the Eddington rate, its high-energy flare becomes detectable with the Fermi/Large Area Telescope, provided that the flare lasts longer than 1.2 months and that we view the source nearly along the rotation axis. In addition, its very high energy flux is marginally detectable with the Cherenkov Telescope Array, provided that the flare lasts longer than a night and that our viewing angle is about 45 deg with respect to the rotation axis.</P>
Tan, Qing-Hua,Gao, Yu,Zhang, Zhi-Yu,Greve, Thomas R.,Jiang, Xue-Jian,Wilson, Christine D.,Yang, Chen-Tao,Bemis, Ashley,Chung, Aeree,Matsushita, Satoki,Shi, Yong,Ao, Yi-Ping,Brinks, Elias,Currie, Malco American Astronomical Society 2018 The Astrophysical journal Vol.860 No.2
<P>We present HCN J = 4 -> 3 and HCO+ J = 4 -> 3 maps of six nearby star-forming galaxies, NGC 253, NGC 1068, IC 342, M82, M83, and NGC 6946, obtained with the James Clerk Maxwell Telescope as part of the MALATANG survey. All galaxies were mapped in the central 2' x 2' region at 14 '' (FWHM) resolution (corresponding to linear scales of similar to 0.2-1.0 kpc). The L-IR-L'(dense) relation, where the dense gas is traced by the HCN J = 4 -> 3 and the HCO+ J = 4 -> 3 emission, measured in our sample of spatially resolved galaxies is found to follow the linear correlation established globally in galaxies within the scatter. We find that the luminosity ratio, L-IR/L'(dense), shows systematic variations with L-IR within individual spatially resolved galaxies, whereas the galaxy-integrated ratios vary little. A rising trend is also found between L-IR/L'(dense) ratio and the warm-dust temperature gauged by the 70 mu m/100 mu m flux ratio. We find that the luminosity ratios of IR/HCN (4-3) and IR/HCO+ (4-3), which can be taken as a proxy for the star formation efficiency (SFE) in the dense molecular gas (SFEdense), appear to be nearly independent of the dense gas fraction (f(dense)) for our sample of galaxies. The SFE of the total molecular gas (SFEmol) is found to increase substantially with f(dense) when combining our data with those on local (ultra) luminous infrared galaxies and high-z quasars. The mean L'(HCN(4-3))/L'(HCO+(4-3)) line ratio measured for the six targeted galaxies is 0.9 +/- 0.6. No significant correlation is found for the L'(HCN(4-3)) L'(HCO+(4-3)) ratio with the star formation rate as traced by L-IR, nor with the warm-dust temperature, for the different populations of galaxies.</P>