@article {214, title = {{Exploring the molecular chemistry and excitation in obscured luminous infrared galaxies: An ALMA mm-wave spectral scan of NGC 4418}}, journal = {ArXiv e-prints}, year = {2015}, keywords = {Astrophysics - Astrophysics of Galaxies}, author = {Costagliola, F. and Sakamoto, K. and Muller, S. and Mart{\'\i}n, S. and Aalto, S. and Harada, N. and van der Werf, P. and Viti, S. and Garcia-Burillo, S. and Spaans, M.} } @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 {215, title = {{Probing highly obscured, self-absorbed galaxy nuclei with vibrationally excited HCN}}, journal = {ArXiv e-prints}, year = {2015}, keywords = {Astrophysics - Astrophysics of Galaxies}, author = {Aalto, S. and Costagliola, F. and Gonzalez-Alfonso, E. and Muller, S. and Sakamoto, K. and Fuller, G.~A. and Garcia-Burillo, S. and van der Werf, P. and Neri, R. and Spaans, M. and Combes, F. and Viti, S. and Muehle, S. and Armus, L. and Evans, A. and Sturm, E. and Cernicharo, J. and Henkel, C. and Greve, T.~R.} } @article {2014A\&A...567A.125G, title = {{Molecular line emission in NGC 1068 imaged with ALMA. I. An AGN-driven outflow in the dense molecular gas}}, journal = {Astronomy and Astrophysics}, volume = {567}, year = {2014}, month = {jul}, pages = {A125}, abstract = {
Aims: We investigate the fueling and the feedback of star formation and nuclear activity in NGC 1068, a nearby (D = 14 Mpc) Seyfert 2 barred galaxy, by analyzing the distribution and kinematics of the molecular gas in the disk. We aim to understand if and how gas accretion can self-regulate.
Methods: We have used the Atacama Large Millimeter Array (ALMA) to map the emission of a set of dense molecular gas (n(H$_{2}$) {\sime} 10$^{5 - 6}$ cm$^{-3}$) tracers (CO(3-2), CO(6-5), HCN(4-3), HCO$^{+}$(4-3), and CS(7-6)) and their underlying continuum emission in the central r \~{} 2 kpc of NGC 1068 with spatial resolutions \~{}0.3{\Prime} - 0.5{\Prime} (\~{}20-35 pc for the assumed distance of D = 14 Mpc).
Results: The sensitivity and spatial resolution of ALMA give an unprecedented detailed view of the distribution and kinematics of the dense molecular gas (n(H$_{2}$) {\ge} 10$^{5 - 6}$cm$^{-3}$) in NGC 1068. Molecular line and dust continuum emissions are detected from a r \~{} 200 pc off-centered circumnuclear disk (CND), from the 2.6 kpc-diameter bar region, and from the r \~{} 1.3 kpc starburst (SB) ring. Most of the emission in HCO$^{+}$, HCN, and CS stems from the CND. Molecular line ratios show dramatic order-of-magnitude changes inside the CND that are correlated with the UV/X-ray illumination by the active galactic nucleus (AGN), betraying ongoing feedback. We used the dust continuum fluxes measured by ALMA together with NIR/MIR data to constrain the properties of the putative torus using CLUMPY models and found a torus radius of 20$^{+6}$$_{-10}$pc. The Fourier decomposition of the gas velocity field indicates that rotation is perturbed by an inward radial flow in the SB ring and the bar region. However, the gas kinematics from r \~{} 50 pc out to r \~{} 400 pc reveal a massive (M$_{mol}$\~{} 2.7$^{+0.9}$$_{-1.2}$ {\times} 10$^{7}$ M$_{\&sun;}$) outflow in all molecular tracers. The tight correlation between the ionized gas outflow, the radio jet, and the occurrence of outward motions in the disk suggests that the outflow is AGN driven.
Conclusions: The molecular outflow is likely launched when the ionization cone of the narrow line region sweeps the nuclear disk. The outflow rate estimated in the CND, dM/dt\~{} 63$^{+21}$$_{-37}$ M$_{\&sun;}$ yr$^{-1}$, is an order of magnitude higher than the star formation rate at these radii, confirming that the outflow is AGN driven. The power of the AGN is able to account for the estimated momentum and kinetic luminosity of the outflow. The CND mass load rate of the CND outflow implies a very short gas depletion timescale of {\l}e}1 Myr. The CND gas reservoir is likely replenished on longer timescales by efficient gas inflow from the outer disk. Based on observations carried out with ALMA in Cycle 0.}, keywords = {galaxies: individual: NGC 1068, galaxies: ISM, galaxies: kinematics and dynamics, galaxies: nuclei, galaxies: Seyfert, radio lines: galaxies}, doi = {10.1051/0004-6361/201423843}, url = {http://adsabs.harvard.edu/abs/2014A\%26A...567A.125G}, author = {S. Garc{\'\i}a-Burillo and Combes, F. and Usero, A. and Aalto, S. and Krips, M. and Viti, S. and Alonso-Herrero, A. and Hunt, L.~K. and Schinnerer, E. and Baker, A.~J. and Boone, F. and Casasola, V. and Colina, L. and F. Costagliola and Eckart, A. and Fuente, A. and Henkel, C. and Labiano, A. and Mart{\'\i}n, S. and Marquez, I. and Muller, S. and Planesas, P. and Ramos Almeida, C. and Spaans, M. and Tacconi, L.~J. and van der Werf, P.~P.} } @article {218, title = {{Molecular line emission in NGC 1068 imaged with ALMA. I. An AGN-driven outflow in the dense molecular gas}}, journal = {\aap}, volume = {567}, year = {2014}, pages = {A125}, keywords = {galaxies: individual: NGC 1068, galaxies: ISM, galaxies: kinematics and dynamics, galaxies: nuclei, galaxies: Seyfert, radio lines: galaxies}, doi = {10.1051/0004-6361/201423843}, author = {Garcia-Burillo, S. and Combes, F. and Usero, A. and Aalto, S. and Krips, M. and Viti, S. and Alonso-Herrero, A. and Hunt, L.~K. and Schinnerer, E. and Baker, A.~J. and Boone, F. and Casasola, V. and Colina, L. and Costagliola, F. and Eckart, A. and Fuente, A. and Henkel, C. and Labiano, A. and Mart{\'\i}n, S. and Marquez, I. and Muller, S. and Planesas, P. and Ramos Almeida, C. and Spaans, M. and Tacconi, L.~J. and van der Werf, P.~P.} } @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 {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 {221, title = {{High-resolution mm and cm study of the obscured LIRG NGC 4418 . A compact obscured nucleus fed by in-falling gas?}}, journal = {\aap}, volume = {556}, year = {2013}, pages = {A66}, keywords = {galaxies: active, galaxies: individual: NGC 4418, galaxies: ISM, galaxies: kinematics and dynamics, galaxies: starburst}, doi = {10.1051/0004-6361/201220634}, author = {Costagliola, F. and Aalto, S. and Sakamoto, K. and Mart{\'\i}n, S. and Beswick, R. and Muller, S. and Kl{\"o}ckner, H.-R.} } @article {2013A\&A...556A..66C, title = {{High-resolution mm and cm study of the obscured LIRG NGC 4418 . A compact obscured nucleus fed by in-falling gas?}}, journal = {Astronomy and Astrophysics}, volume = {556}, year = {2013}, month = {aug}, pages = {A66}, abstract = {Context. Understanding the nature of the power-source in luminous infrared galaxies (LIRG) is difficult due to their extreme obscuration. Observations at radio and mm wavelengths can penetrate large columns of dust and gas and provide unique insights into the properties of the compact obscured nuclei of LIRGs.
Aims: The aim of this study is to constrain the dynamics, structure, and feeding of the compact nucleus of NGC 4418, and to reveal the nature of the main hidden power-source: starburst or active galactic nucleus (AGN).
Methods: We obtained high spatial resolution observations of NGC 4418 at 1.4 and 5 GHz with MERLIN, and at 230 and 270 GHz with the SMA in very extended configuration. We used the continuum morphology and flux density to estimate the size of the emitting region, the star formation rate, and the dust temperature. Emission lines were used to study kinematics through position-velocity diagrams. Molecular emission was studied with population diagrams and by fitting a local thermal equilibrium (LTE) synthetic spectrum.
Results: We detect bright 1-mm-line emission from CO, HC$_{3}$N, HNC, and C$^{34}$S and 1.4 GHz absorption from HI. The CO 2-1 emission and HI absorption can be fit by two velocity components at 2090 and 2180 km s$^{-1}$. We detect vibrationally excited HC$_{3}$N and HNC, with T$_{vib}$ \~{} 300 K. Molecular excitation is consistent with a layered temperature structure, with three main components at 80, 160, and 300 K. For the hot component we estimate a source size of less than 5 pc. The nuclear molecular gas surface density of 10$^{4}$M$_{\&sun;}$ pc$^{-2}$ is extremely high and similar to that found in the ultra-luminous infrared galaxy (ULIRG) Arp220.
Conclusions: Our observations confirm the presence of a molecular and atomic in-flow, previously suggested by Herschel observations, which is feeding the activity in the center of NGC 4418. Molecular excitation confirms the presence of a very compact, hot dusty core. If a starburst is responsible for the observed IR flux, this has to be at least as extreme as the one in the ULIRG Arp 220, with an age of 3-10 Myr and a star formation rate {\gt}10 M$_{\&sun;}$ yr$^{-1}$. If an AGN is present, it must be extremely Compton-thick. Appendix A is only available in electronic form at http://www.aanda.org}, keywords = {galaxies: active, galaxies: individual: NGC 4418, galaxies: ISM, galaxies: kinematics and dynamics, galaxies: starburst}, doi = {10.1051/0004-6361/201220634}, url = {http://adsabs.harvard.edu/abs/2013A\%26A...556A..66C}, author = {F. Costagliola and Aalto, S. and Sakamoto, K. and Mart{\'\i}n, S. and Beswick, R. and Muller, S. and Kl{\"o}ckner, H.-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 {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...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.} } @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.} }