@article {2015ApJ...799...11X, title = {{ALMA Observations of Warm Dense Gas in NGC 1614 - Breaking of the Star Formation Law in the Central Kiloparsec}}, journal = {The Astrophysical Journal}, volume = {799}, year = {2015}, month = {jan}, pages = {11}, abstract = {We present ALMA Cycle-0 observations of the CO (6-5) line emission and of the 435 {$μ$}m dust continuum emission in the central kiloparsec of NGC 1614, a local luminous infrared galaxy at a distance of 67.8 Mpc (1$\{$$^{\prime \prime }$$\}$= 329 pc). The CO emission is well resolved by the ALMA beam (0.{\textquoteright}{\textquoteright}26 {\times} 0.{\textquoteright}{\textquoteright}20) into a circumnuclear ring, with an integrated flux of f $_{ CO(6-5)}$ = 898 ({\plusmn} 153) Jy km s$^{-1}$, which is 63({\plusmn} 12)\% of the total CO (6-5) flux measured by Herschel. The molecular ring, located between 100 pc {\l}t} r {\l}t} 350 pc from the nucleus, looks clumpy and includes seven unresolved (or marginally resolved) knots with median velocity dispersion of \~{}40 km s$^{-1}$. These knots are associated with strong star formation regions with {$Σ$}$_{SFR}$ \~{} 100 M $_{\&sun;}$ yr$^{-1}$ kpc$^{-2}$ and {$Σ$} $_{Gas}${\tilde} 10$^{4}$ $\{$M$\}$\_{\sun} pc$^{-2}$. The non-detections of the nucleus in both the CO (6-5) line emission and the 435 {$μ$}m continuum rule out, with relatively high confidence, a Compton-thick active galactic nucleus in NGC 1614. Comparisons with radio continuum emission show a strong deviation from an expected local correlation between {$Σ$}$_{Gas}$ and {$Σ$}$_{SFR}$, indicating a breakdown of the Kennicutt-Schmidt law on the linear scale of \~{}100 pc. The National Radio Astronomy Observatory is a facility of the National Science Foundation operated under cooperative agreement by Associated Universities, Inc.}, keywords = {galaxies: active, galaxies: evolution, galaxies: general, galaxies: interactions, galaxies: ISM, galaxies: magnetic fields, galaxies: nuclei, galaxies: starburst, submillimeter: galaxies}, doi = {10.1088/0004-637X/799/1/11}, url = {http://adsabs.harvard.edu/abs/2015ApJ...799...11X}, author = {Xu, C.~K. and Cao, C. and Lu, N. and Gao, Y. and Diaz-Santos, T. and R. Herrero-Illana and Meijerink, R. and Privon, G. and Zhao, Y.-H. and Evans, A.~S. and K{\"o}nig, S. and Mazzarella, J.~M. and Aalto, S. and Appleton, P. and Armus, L. and Charmandaris, V. and Chu, J. and Haan, S. and Inami, H. and Murphy, E.~J. and Sanders, D.~B. and Schulz, B. and van der Werf, P.} } @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 {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 {2011A\&A...528A..30C, title = {{Molecules as tracers of galaxy evolution: an EMIR survey. I. Presentation of the data and first results}}, journal = {Astronomy and Astrophysics}, volume = {528}, year = {2011}, month = {apr}, pages = {A30}, abstract = {
Aims: We investigate the molecular gas properties of a sample of 23 galaxies in order to find and test chemical signatures of galaxy evolution and to compare them to IR evolutionary tracers.
Methods: Observation at 3 mm wavelengths were obtained with the EMIR broadband receiver, mounted on the IRAM 30 m telescope on Pico Veleta, Spain. We compare the emission of the main molecular species with existing models of chemical evolution by means of line intensity ratios diagrams and principal component analysis.
Results: We detect molecular emission in 19 galaxies in two 8 GHz-wide bands centred at 88 and 112 GHz. The main detected molecules are CO, $^{13}$CO, HCN, HNC, HCO$^{+}$, CN, and C$_{2}$H. We also detect HC$_{3}$N J = 10-9 in the galaxies IRAS 17208, IC 860, NGC 4418, NGC 7771, and NGC 1068. The only HC$_{3}$N detections are in objects with HCO$^{+}$/HCN {\l}t} 1. Galaxies with the highest HC$_{3}$N/HCN ratios have warm IRAS colours (60/100 {$μ$}m {\gt} 0.8). The brightest HC$_{3}$N emission is found in IC 860, where we also detect the molecule in its vibrationally excited state. We find low HNC/HCN line ratios ({\l}t}0.5), that cannot be explained by existing PDR or XDR chemical models. The intensities of HCO+ and HNC appear anti-correlated. No correlation is found between the HNC/HCN line ratio and dust temperature. All HNC-bright objects are either luminous IR galaxies (LIRG) or Seyferts. Galaxies with bright polycyclic aromatic hydrocarbons (PAH) emission show low HNC/HCO$^{+}$ ratios. The CO/$^{13}$CO ratio is positively correlated with the dust temperature and is generally higher than in our galaxy. The emission of CN and C$^{18}$O is correlated.
Conclusions: Bright HC$_{3}$N emission in HCO$^{+}$-faint objects may imply that these are not dominated by X-ray chemistry. Thus the HCN/HCO$^{+}$ line ratio is not, by itself, a reliable tracer of XDRs. Bright HC$_{3}$N and faint HCO$^{+}$ could be signatures of embedded star-formation, instead of AGN activity. Mechanical heating caused by supernova explosions may be responsible for the low HNC/HCN and high HCO$^{+}$/HCN ratios in some starbursts. We cannot exclude, however, that the discussed trends are largely caused by optical depth effects or excitation. Chemical models alone cannot explain all properties of the observed molecular emission. Better constraints to the gas spacial distribution and excitation are needed to distinguish abundance and excitation effects. Appendices are only available in electronic form http://www.aanda.org}, keywords = {evolution, galaxies: active, galaxies: evolution, galaxies: ISM, ISM: molecules}, doi = {10.1051/0004-6361/201015628}, url = {http://adsabs.harvard.edu/abs/2011A\%26A...528A..30C}, author = {F. Costagliola and Aalto, S. and M. Rodr{\'\i}guez and Muller, S. and Spoon, H.~W.~W. and Mart{\'\i}n, S. and M. A. P{\'e}rez-Torres and Alberdi, A. and Lindberg, J.~E. and Batejat, F. and J{\"u}tte, E. and van der Werf, P. and Lahuis, F.} }