@article {2015A\&A...574A..85A, title = {{High resolution observations of HCN and HCO$^{+}$J = 3-2 in the disk and outflow of Mrk 231. Detection of vibrationally excited HCN in the warped nucleus}}, journal = {Astronomy and Astrophysics}, volume = {574}, year = {2015}, month = {feb}, pages = {A85}, abstract = {
Aims: Our goal is to study molecular gas properties in nuclei and large scale outflows/winds from active galactic nuclei (AGNs) and starburst galaxies.
Methods: We obtained high resolution (0.{\#779}25 to 0.{\#779}90) observations of HCN and HCO$^{+}$J = 3 {\rarr} 2 of the ultraluminous QSO galaxy Mrk 231 with the IRAM Plateau de Bure Interferometer (PdBI).
Results: We find luminous HCN and HCO$^{+}$J = 3 {\rarr} 2 emission in the main disk and we detect compact (r {\l}sim} 0{\textquoteright}{\textquoteright}\&dotbelow;1 (90 pc)) vibrationally excited HCN J = 3 {\rarr} 2{$ν$}$_{2}$ = 1f emission centred on the nucleus. The velocity field of the vibrationally excited HCN is strongly inclined (position angle PA = 155{\deg}) compared to the east-west rotation of the main disk. The nuclear (r {\l}sim} 0.{\#779}1) molecular mass is estimated to 8 {\times} 10$^{8}$ M$_{\&sun;}$ with an average N(H$_{2}$) of 1.2 {\times} 10$^{24}$ cm$^{-2}$. Prominent, spatially extended ({\gsim}350 pc) line wings are found for HCN J = 3 {\rarr} 2 with velocities up to {\plusmn} 750 km s$^{-1}$. Line ratios indicate that the emission is emerging in dense gas n = 10$^{4}$-5 {\times} 10$^{5}$ cm$^{-3}$ of elevated HCN abundance X(HCN) = 10$^{-8}$-10$^{-6}$. The highest X(HCN) also allows for the emission to originate in gas of more moderate density. We tentatively detect nuclear emission from the reactive ion HOC$^{+}$ with HCO$^{+}$/HOC$^{+}$ = 10-20.
Conclusions: The HCN {$ν$}$_{2}$ = 1f line emission is consistent with the notion of a hot, dusty, warped inner disk of Mrk 231 where the {$ν$}$_{2}$ = 1f line is excited by bright mid-IR 14 {$μ$}m continuum. We estimate the vibrational temperature T$_{vib}$ to 200-400 K. Based on relative source sizes we propose that 50\% of the main HCN emission may have its excitation affected by the radiation field through IR pumping of the vibrational ground state. The HCN emission in the line wings, however, is more extended and thus likely not strongly affected by IR pumping. Our results reveal that dense clouds survive (and/or are formed) in the AGN outflow on scales of at least several hundred pc before evaporating or collapsing. The elevated HCN abundance in the outflow is consistent with warm chemistry possibly related to shocks and/or X-ray irradiated gas. An upper limit to the mass and momentum flux is 4 {\times} 10$^{8}$ M$_{\&sun;}$ and 12L$_{AGN}$/c, respectively, and we discuss possible driving mechanisms for the dense outflow. Based on observations carried out with the IRAM Plateau de Bure Interferometer. IRAM is supported by INSU/CNRS (France), MPG (Germany) and IGN (Spain).The reduced data cubes are only available at the CDS via anonymous ftp to http://cdsarc.u-strasbg.fr (ftp://130.79.128.5) or via http://cdsarc.u-strasbg.fr/viz-bin/qcat?J/A+A/574/A85}, keywords = {galaxies: active, galaxies: evolution, galaxies: individual: Mrk 231, ISM: jets and outflows, ISM: molecules, quasars: general}, doi = {10.1051/0004-6361/201423987}, url = {http://adsabs.harvard.edu/abs/2015A\%26A...574A..85A}, author = {Aalto, S. and S. Garc{\'\i}a-Burillo and Muller, S. and Winters, J.~M. and Gonzalez-Alfonso, E. and van der Werf, P. and Henkel, C. and F. Costagliola and Neri, R.} } @article {2014A\&A...570A..28V, title = {{Molecular line emission in NGC 1068 imaged with ALMA. II. The chemistry of the dense molecular gas}}, journal = {Astronomy and Astrophysics}, volume = {570}, year = {2014}, month = {oct}, pages = {A28}, abstract = {
Aims: We present a detailed analysis of Atacama Large Millimeter/submillimeter Array (ALMA) Bands 7 and 9 data of CO, HCO$^{+}$, HCN, and CS, augmented with Plateau de Bure Interferometer (PdBI) data of the \~{}200 pc circumnuclear disc (CND) and the \~{}1.3 kpc starburst ring (SB ring) of NGC 1068, a nearby (D = 14 Mpc) Seyfert 2 barred galaxy. We aim to determine the physical characteristics of the dense gas present in the CND, and to establish whether the different line intensity ratios we find within the CND, as well as between the CND and the SB ring, are due to excitation effects (gas density and temperature differences) or to a different chemistry.
Methods: We estimate the column densities of each species in local thermodynamic equilibrium (LTE). We then compute large one-dimensional, non-LTE radiative transfer grids (using RADEX) by using only the CO transitions first, and then all the available molecules to constrain the densities, temperatures, and column densities within the CND. We finally present a preliminary set of chemical models to determine the origin of the gas.
Results: We find that, in general, the gas in the CND is very dense ({\gt}10$^{5}$ cm$^{-3}$) and hot (T{\gt} 150 K), with differences especially in the temperature across the CND. The AGN position has the lowest CO/HCO$^{+}$, CO/HCN, and CO/CS column density ratios. The RADEX analyses seem to indicate that there is chemical differentiation across the CND. We also find differences between the chemistry of the SB ring and some regions of the CND; the SB ring is also much colder and less dense than the CND. Chemical modelling does not succeed in reproducing all the molecular ratios with one model per region, suggesting the presence of multi-gas phase components.
Conclusions: The LTE, RADEX, and chemical analyses all indicate that more than one gas-phase component is necessary to uniquely fit all the available molecular ratios within the CND. A higher number of molecular transitions at the ALMA resolution is necessary to determine quantitatively the physical and chemical characteristics of these components. Tables 5-11 are available in electronic form at http://www.aanda.org}, keywords = {galaxies: active, galaxies: individual: NGC 1068, galaxies: ISM, galaxies: nuclei, molecular processes, radio lines: galaxies}, doi = {10.1051/0004-6361/201424116}, url = {http://adsabs.harvard.edu/abs/2014A\%26A...570A..28V}, author = {Viti, S. and S. Garc{\'\i}a-Burillo and Fuente, A. and Hunt, L.~K. and Usero, A. and Henkel, C. and Eckart, A. and Mart{\'\i}n, S. and Spaans, M. and Muller, S. and Combes, F. and Krips, M. and Schinnerer, E. and Casasola, V. and F. Costagliola and Marquez, I. and Planesas, P. and van der Werf, P.~P. and Aalto, S. and Baker, A.~J. and Boone, F. and Tacconi, L.~J.} } @article {217, title = {{Molecular line emission in NGC 1068 imaged with ALMA. II. The chemistry of the dense molecular gas}}, journal = {\aap}, volume = {570}, year = {2014}, pages = {A28}, keywords = {galaxies: active, galaxies: individual: NGC 1068, galaxies: ISM, galaxies: nuclei, molecular processes, radio lines: galaxies}, doi = {10.1051/0004-6361/201424116}, author = {Viti, S. and Garcia-Burillo, S. and Fuente, A. and Hunt, L.~K. and Usero, A. and Henkel, C. and Eckart, A. and Mart{\'\i}n, S. and Spaans, M. and Muller, S. and Combes, F. and Krips, M. and Schinnerer, E. and Casasola, V. and Costagliola, F. and Marquez, I. and Planesas, P. and van der Werf, P.~P. and Aalto, S. and Baker, A.~J. and Boone, F. and Tacconi, L.~J.} } @article {2012A\&A...537A..44A, title = {{Detection of HCN, HCO$^{+}$, and HNC in the Mrk 231 molecular outflow. Dense molecular gas in the AGN wind}}, journal = {Astronomy and Astrophysics}, volume = {537}, year = {2012}, month = {jan}, pages = {A44}, abstract = {
Aims: Our goal is to study gas properties in large-scale molecular outflows and winds from active galactic nuclei (AGNs) and starburst galaxies.
Methods: We obtained high-resolution (1.{\textquoteright}{\textquoteright}55 {\times} 1.{\textquoteright}{\textquoteright}28) observations of HCN, HCO$^{+}$, HNC 1-0 and HC$_{3}$N 10-9 of the ultraluminous galaxy (ULIRG) Mrk 231 with the IRAM Plateau de Bure Interferometer.
Results: We detect luminous emission from HCN, HCO$^{+}$ and HNC 1-0 in the QSO ULIRG Mrk 231. All three lines show broad line wings - which are particularly prominent for HCN. Velocities are found to be similar ( {\ap} {\plusmn} 750 km s$^{-1}$) to those found for CO 1-0. This is the first time bright HCN, HCO$^{+}$ and HNC emission has been detected in a large-scale galactic outflow. We find that both the blue- and red-shifted line wings are spatially extended by at least 0.{\textquoteright}{\textquoteright}75 ({\gt}700 pc) in a north-south direction. The line wings are brighter (relative to the line center intensity) in HCN than in CO 1-0 and line ratios suggest that the molecular outflow consists of dense (n {\gt} 10$^{4}$ cm$^{-3}$) and clumpy gas with a high HCN abundance X(HCN) {\gt} 10$^{-8}$. These properties are consistent with the molecular gas being compressed and fragmented by shocks in the outflow. Alternatively, HCN is instead pumped by mid-IR continuum, but we propose that this effect is not strong for the spatially extended outflowing gas. In addition, we find that the rotation of the main disk, in east-west direction, is also evident in the HCN, HCO$^{+}$ and HNC line emission. An unexpectedly bright HC$_{3}$N 10-9 line is detected inside the central 400 pc of Mrk 231. This HC$_{3}$N emission may emerge from a shielded, dust-enshrouded region within the inner 40-50 pc where the gas is heated to high temperatures (200-300 K) by the AGN. Based on observations carried out with the IRAM Plateau de Bure Interferometer. IRAM is supported by INSU/CNRS (France), MPG (Germany) and IGN (Spain).}, keywords = {galaxies: active, galaxies: evolution, galaxies: individual: Mrk 231, ISM: molecules, quasars: general, radio lines: ISM}, doi = {10.1051/0004-6361/201117919}, url = {http://adsabs.harvard.edu/abs/2012A\%26A...537A..44A}, author = {Aalto, S. and S. Garc{\'\i}a-Burillo and Muller, S. and Winters, J.~M. and van der Werf, P. and Henkel, C. and F. Costagliola and Neri, R.} }