The Dense Molecular Gas in the Circumnuclear Disk of NGC 1068

Kamenetzky, J.; Glenn, J.; Maloney, Philip R.; Aguirre, James E.; Bock, J. J.; Bradford, C. M.; Earle, L.; Inami, Hanae; Matsuhara, Hideo; Murphy, E. J.; Naylor, B. J.; Nguyen, Hien; Žmuidzinas, J.

doi:10.1088/0004-637x/731/2/83

Cited by 44 publications

(71 citation statements)

References 44 publications

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“…We caution, however, that these findings -in particular the numbers shown below -are rather uncertain, and will be only indicative. Instead of the Bayesian probability, which is the integral of all probabilities in the parameter space (e.g., Weiß et al 2005;Hailey-Dunsheath et al 2012;Kamenetzky et al 2011;Rangwala et al 2011), we analyze the trend of the solutions with the highest likelihood. The maximum likelihood function of a given parameter (or given parameters) is based on the best fitting results in the whole parameter space.…”

Section: Discussionmentioning

confidence: 99%

Physical conditions of molecular gas in the Circinus galaxy Multi-JCO and Ci³PP₀observations

Zhang

Henkel

Gao

et al. 2014

A&A

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We report mapping observations of the 12 CO J = 3 → 2, 4 → 3, 6 → 5, and 7 → 6 transitions and the C i 3 P 1 → 3 P 0 (C i) 492 GHz transition toward the central 40 ×40 region of the Circinus galaxy, using the Atacama Pathfinder EXperiment (APEX) telescope. We also detected 13 CO J = 3 → 2 at the central position of Circinus. These observations are to date the highest CO transitions reported in Circinus. With large velocity gradient (LVG) modeling and likelihood analysis we try to obtain density, temperature, and column density of the molecular gas in three regions: the nuclear region (D < 18 ∼ 360 pc), the entire central 45 (D < 45 ∼ 900 pc) region, and the star-forming (S-F) ring (18 < D < 45 ). In the nuclear region, we can fit the CO excitation with a single excitation component, yielding an average condition of n H 2 ∼ 10 3.2 cm −3 , T kin ∼ 200 K, and d /dr ∼ 3 km s −1 pc −1 . In the entire 45 region, which covers both the nucleus and the S-F ring, two excitation components are needed with n H 2 ∼ 10 4.2 cm −3 and 10 3.0 cm −3 , T kin ∼ 60 K and 30 K, and M H 2 ∼ 2.3 × 10 7 M and 6.6 × 10 7 M , respectively. The gas excitation in the S-F ring can also be fitted with two LVG components, after subtracting the CO fluxes in the 18 nuclear region. The S-F ring region contributes 80% of the molecular mass in the 45 region. For the entire 45 region, we find a standard conversion factor of N(H 2 )/I CO 1→0 = 0.37 × 10 20 cm −2 (K km s −1 ) −1 , about 1/5 of the Galactic disk value. The luminosity ratios of C i and 12 CO J = 3 → 2 (R CI/CO 3→2 ) in Circinus basically follow a linear trend, similar to that obtained in high-redshift galaxies. The average R CI/CO J = 3 → 2 in Circinus is found to be ∼0.2, lying at an intermediate value between non-AGN nuclear regions and high-redshift galaxies.

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Section: Discussionmentioning

confidence: 99%

Physical conditions of molecular gas in the Circinus galaxy Multi-JCO and Ci³PP₀observations

Zhang

Henkel

Gao

et al. 2014

A&A

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“…In addition to RADEX, we use a Bayesian likelihood code (Ward et al 2003;Panuzzo et al 2010;Kamenetzky et al 2011). The Bayesian likelihood code determines the most probable solutions for the physical conditions of the molecular gas by comparing the RADEX calculated and the observed 12 CO and 13 CO line fluxes.…”

Section: Likelihood Analysismentioning

confidence: 99%

LUMINOUS INFRARED GALAXIES WITH THE SUBMILLIMETER ARRAY. IV.¹²COJ= 6-5 OBSERVATIONS OF VV 114

Sliwa

Wilson

Krips

et al. 2013

ApJ

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We present high-resolution (∼2. 5) observations of 12 CO J = 6-5 toward the luminous infrared galaxy VV 114 using the Submillimeter Array. We detect 12 CO J = 6-5 emission from the eastern nucleus of VV 114 but do not detect the western nucleus or the central region. We combine the new 12 CO J = 6-5 observations with previously published or archival low-J CO observations, which include 13 CO J = 1-0 Atacama Large Millimeter/submillimeter Array cycle 0 observations, to analyze the beam-averaged physical conditions of the molecular gas in the eastern nucleus. We use the radiative transfer code RADEX and a Bayesian likelihood code to constrain the temperature (T kin ), density (n H 2 ), and column density (N12 CO ) of the molecular gas. We find that the most probable scenario for the eastern nucleus is a cold (T kin = 38 K), moderately dense (n H 2 = 10 2.89 cm −3 ) molecular gas component. We find that the most probable 12 CO to 13 CO abundance ratio ([ 12 CO]/[ 13 CO]) is 229, which is roughly three times higher than the Milky Way value. This high abundance ratio may explain the observed high 12 CO/ 13 CO line ratio (>25). The unusual 13 CO J = 2-1/J = 1-0 line ratio of 0.6 is produced by a combination of moderate 13 CO optical depths (τ = 0.4-1.1) and extremely subthermal excitation temperatures. We measure the CO-to-H 2 conversion factor, α CO , to be 0.5 +0.6 −0.3 M (K km s −1 pc 2 ) −1 , which agrees with the widely used factor for ultra luminous infrared galaxies of Downes & Solomon (α CO = 0.8 M (K km s −1 pc 2 ) −1 ).

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“…García-Burillo et al 2002;Wang 2004;Usero et al 2004;Fuente et al 2008;Aalto et al 2011;Martín et al 2011;Aladro et al 2013;Costagliola et al 2011;Kamenetzky et al 2011;Watanabe et al 2014). A common trend observed in recent surveys is a chemical diversity and complexity that is hard to explain with a one-component gas phase.…”

Section: Introductionmentioning

confidence: 99%

“…Usero et al 2004;Israel 2009;Kamenetzky et al 2011;Hailey-Dunsheath et al 2012;Aladro et al 2013). Interferometric observations of CO, as well as HCN, HCO + , CS, and SiO (e.g.…”

Section: Introductionmentioning

confidence: 99%

Molecular line emission in NGC 1068 imaged with ALMA

Viti

García‐Burillo

Fuente

et al. 2014

A&A

142

225

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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 (>10 5 cm −3 ) and hot (T > 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.

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The Dense Molecular Gas in the Circumnuclear Disk of NGC 1068

Cited by 44 publications

References 44 publications

Physical conditions of molecular gas in the Circinus galaxy Multi-JCO and Ci³PP₀observations

Physical conditions of molecular gas in the Circinus galaxy Multi-JCO and Ci³PP₀observations

LUMINOUS INFRARED GALAXIES WITH THE SUBMILLIMETER ARRAY. IV.¹²COJ= 6-5 OBSERVATIONS OF VV 114

Molecular line emission in NGC 1068 imaged with ALMA

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The Dense Molecular Gas in the Circumnuclear Disk of NGC 1068

Cited by 44 publications

References 44 publications

Physical conditions of molecular gas in the Circinus galaxy Multi-JCO and Ci3PP0observations

Physical conditions of molecular gas in the Circinus galaxy Multi-JCO and Ci3PP0observations

LUMINOUS INFRARED GALAXIES WITH THE SUBMILLIMETER ARRAY. IV.12COJ= 6-5 OBSERVATIONS OF VV 114

Molecular line emission in NGC 1068 imaged with ALMA

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Physical conditions of molecular gas in the Circinus galaxy Multi-JCO and Ci³PP₀observations

Physical conditions of molecular gas in the Circinus galaxy Multi-JCO and Ci³PP₀observations

LUMINOUS INFRARED GALAXIES WITH THE SUBMILLIMETER ARRAY. IV.¹²COJ= 6-5 OBSERVATIONS OF VV 114