@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.} } @article {2012A\&A...546A..68A, title = {{Winds of change - a molecular outflow in NGC 1377?. The anatomy of an extreme FIR-excess galaxy}}, journal = {Astronomy and Astrophysics}, volume = {546}, year = {2012}, month = {oct}, pages = {A68}, abstract = {
Aims: Our goal was to investigate the molecular gas distribution and kinematics in the extreme far-infrared (FIR) excess galaxy NGC 1377 and to address the nature and evolutionary status of the buried source.
Methods: We used high- (0{\textquoteright}{\textquoteright}65 {\times} 0{\textquoteright}{\textquoteright}52, (65 {\times} 52 pc)) and low- (4{\textquoteright}{\textquoteright}88 {\times} 2{\textquoteright}{\textquoteright}93) resolution SubMillimeter Array (SMA) observations to image the $^{12}$CO and $^{13}$CO 2-1 line emission.
Results: We find bright, complex $^{12}$CO 2-1 line emission in the inner 400 pc of NGC 1377. The $^{12}$CO 2-1 line has wings that are tracing a kinematical component that appears to be perpendicular to the component traced by the line core. Together with an intriguing X-shape of the integrated intensity and dispersion maps, this suggests that the molecular emission of NGC 1377 consists of a disk-outflow system. Lower limits to the molecular mass and outflow rate are M$_{out}$(H$_{2}$) {\gt} 1 {\times} 10$^{7}$ M$_{\&sun;}$ and {\.M} {\gt} 8 M$_{\&sun;}$ yr$^{-1}$. The age of the proposed outflow is estimated to be 1.4 Myr, the extent to be 200 pc and the outflow speed to be V$_{out}$ = 140 km s$^{-1}$. The total molecular mass in the SMA map is estimated to M$_{tot}$(H$_{2}$) = 1.5 {\times} 10$^{8}$ M$_{\&sun;}$ (on a scale of 400 pc) while in the inner r = 29 pc the molecular mass is M$_{core}$(H$_{2}$) = 1.7 {\times} 10$^{7}$ M$_{\&sun;}$ with a corresponding H$_{2}$ column density of N(H$_{2}$) = 3.4 {\times} 10$^{23}$ cm$^{-2}$ and an average $^{12}$CO 2-1 brightness temperature of 19 K. $^{13}$CO 2-1 emission is found at a factor 10 fainter than $^{12}$CO in the low-resolution map while C$^{18}$O 2-1 remains undetected. We find weak 1 mm continuum emission of 2.4 mJy with spatial extent less than 400 pc.
Conclusions: Observing the molecular properties of the FIR-excess galaxy NGC 1377 allows us to probe the early stages of nuclear activity and the onset of feedback in active galaxies. The age of the outflow supports the notion that the current nuclear activity is young - a few Myr. The outflow may be powered by radiation pressure from a compact, dust enshrouded nucleus, but other driving mechanisms are possible. The buried source may be an active galactic nucleus (AGN) or an extremely young (1 Myr) compact starburst. Limitations on size and mass lead us to favor the AGN scenario, but additional studies are required to settle this question. In either case, the wind with its implied mass outflow rate will quench the nuclear power source within the very short time of 5-25 Myr. It is possible, however, that the gas is unable to escape the galaxy and may eventually fall back onto NGC 1377 again.}, keywords = {galaxies: active, galaxies: evolution, galaxies: individual: NGC 1377, galaxies: starburst, ISM: molecules, radio lines: ISM}, doi = {10.1051/0004-6361/201118052}, url = {http://adsabs.harvard.edu/abs/2012A\%26A...546A..68A}, author = {Aalto, S. and Muller, S. and Sakamoto, K. and Gallagher, J.~S. and Mart{\'\i}n, S. and F. Costagliola} } @article {2011A\&A...527A.150L, title = {{A survey of HC$_{3}$N in extragalactic sources. Is HC$_{3}$N a tracer of activity in ULIRGs?}}, journal = {Astronomy and Astrophysics}, volume = {527}, year = {2011}, month = {mar}, pages = {A150}, abstract = {Context. HC$_{3}$N is a molecule that is mainly associated with Galactic star-forming regions, but it has also been detected in extragalactic environments.
Aims: To present the first extragalactic survey of HC$_{3}$N, when combining earlier data from the literature with six new single-dish detections, and to compare HC$_{3}$N with other molecular tracers (HCN, HNC), as well as other properties (silicate absorption strength, IR flux density ratios, C ii flux, and megamaser activity).
Methods: We present mm IRAM 30 m, OSO 20 m, and SEST observations of HC$_{3}$N rotational lines (mainly the J = 10-9 transition) and of the J = 1-0 transitions of HCN and HNC. Our combined HC$_{3}$N data account for 13 galaxies (excluding the upper limits reported for the non-detections), while we have HCN and HNC data for more than 20 galaxies.
Results: A preliminary definition {\textquoteright}{\textquoteright}HC$_{3}$N-luminous galaxy{\textquoteright}{\textquoteright} is made based upon the HC$_{3}$N/HCN ratio. Most (\~{}80\%) HC$_{3}$N-luminous galaxies seem to be deeply obscured galaxies and (U)LIRGs. A majority (\~{}60\% or more) of the HC$_{3}$N-luminous galaxies in the sample present OH mega- or strong kilomaser activity. A possible explanation is that both HC$_{3}$N and OH megamasers need warm dust for their excitation. Alternatively, the dust that excites the OH megamaser offers protection against UV destruction of HC$_{3}$N. A high silicate absorption strength is also found in several of the HC$_{3}$N-luminous objects, which may help the HC$_{3}$N to survive. Finally, we find that a high HC$_{3}$N/HCN ratio is related to a high dust temperature and a low C ii flux. Appendix is only available in electronic form at http://www.aanda.org}, keywords = {galaxies: active, galaxies: ISM, galaxies: starburst, ISM: molecules, radio lines: galaxies, radio lines: ISM}, doi = {10.1051/0004-6361/201015565}, url = {http://adsabs.harvard.edu/abs/2011A\%26A...527A.150L}, author = {Lindberg, J.~E. and Aalto, S. and F. Costagliola and P{\'e}rez-Beaupuits, J.-P. and Monje, R. and Muller, S.} } @article {2010A\&A...515A..71C, title = {{Vibrationally excited HC$_{3}$N in NGC 4418}}, journal = {Astronomy and Astrophysics}, volume = {515}, year = {2010}, month = {jun}, pages = {A71}, abstract = {
Aims: We investigate the molecular gas properties of the deeply obscured luminous infrared galaxy NGC 4418. We address the excitation of the complex molecule HC$_{3}$N to determine whether its unusually luminous emission is related to the nature of the buried nuclear source.
Methods: We use IRAM 30 m and JCMT observations of rotational and vibrational lines of HC$_{3}$N to model the excitation of the molecule by means of rotational diagrams.
Results: We report the first confirmed extragalactic detection of vibrational lines of HC$_{3}$N. We detect 6 different rotational transitions ranging from J = 10-9 to J = 30-29 in the ground vibrational state and obtain a tentative detection of the J = 38-37 line. We also detect 7 rotational transitions of the vibrationally excited states v$_{6}$ and v$_{7}$, with angular momenta ranging from J = 10-9 to 28-27. The energies of the upper states of the observed transitions range from 20 to 850 K. In the optically thin regime, we find that the rotational transitions of the vibrational ground state can be fitted for two temperatures, 30 K and 260 K, while the vibrationally excited levels can be fitted for a rotational temperature of 90 K and a vibrational temperature of 500 K. In the inner 300 pc of NGC 4418, we estimate a high HC$_{3}$N abundance, of the order of 10$^{-7}$.
Conclusions: The excitation of the HC$_{3}$N molecule responds strongly to the intense radiation field and the presence of warm, dense gas and dust at the center of NGC 4418. The intense HC$_{3}$N line emission is a result of both high abundances and excitation. The properties of the HC$_{3}$N emitting gas are similar to those found for hot cores in Sgr B2, which implies that the nucleus ({\l}t}300 pc) of NGC 4418 is reminiscent of a hot core. The potential presence of a compact, hot component (T = 500 K) is also discussed.}, keywords = {galaxies: active, galaxies: evolution, galaxies: starburst, globular clusters: individual: NGC 4418, ISM: molecules, radio lines: ISM}, doi = {10.1051/0004-6361/200913370}, url = {http://adsabs.harvard.edu/abs/2010A\%26A...515A..71C}, author = {F. Costagliola and Aalto, S.} }