Distributions of molecules in the circumnuclear disk and surrounding starburst ring in the Seyfert galaxy NGC 1068 observed with ALMA

Abstract

Sensitive observations with ALMA allow astronomers to observe the detailed distributions of molecules with relatively weak intensity in nearby galaxies. In particular, we report distributions of several molecular transitions including shock and dust related species (${}^{13}$CO $J$ = 1--0, C${}^{18}$O $J$ = 1--0, ${}^{13}$CN $N$ = 1--0, CS $J$ = 2--1, SO $J_N$ = 3${}_2$--2${}_1$, HNCO $J_{Ka,Kc}$ = 5${}_{0,5}$--4${}_{0,4}$, HC${}_3$N $J$ = 11--10, 12--11, CH${}_3$OH $J_K$ = 2${}_K$--1${}_K$, and CH${}_3$CN $J_K$ = 6${}_K$--5${}_K$) in the nearby Seyfert 2 galaxy NGC 1068 observed with the ALMA early science program. The central $\sim$1 arcmin ($\sim$4.3 kpc) of this galaxy was observed in the 100 GHz region covering $\sim$96--100 GHz and $\sim$108--111 GHz with an angular resolution of $\sim 4"\times 2"$ (290 pc$\times$140 pc) to study the effects of an active galactic nucleus and its surrounding starburst ring on molecular abundances. Here, we present images and report a classification of molecular distributions into three main categories: (1) Molecules concentrated in the circumnuclear disk (CND) (SO $J_N$ = 3${}_2$--2${}_1$, HC${}_3$N $J$ = 11--10, 12--11, and CH${}_3$CN $J_K$ = 6${}_K$--5${}_K$), (2) Molecules distributed both in the CND and the starburst ring (CS $J$ = 2--1 and CH${}_3$OH $J_K$ = 2${}_K$--1${}_K$), (3) Molecules distributed mainly in the starburst ring (${}^{13}$CO $J$ = 1--0 and C${}^{18}$O $J$ = 1--0). Since most of the molecules such as HC${}_3$N observed in the CND are easily dissociated by UV photons and X-rays, our results indicate that these molecules must be effectively shielded. In the starburst ring, the relative intensity of methanol at each clumpy region is not consistent with those of ${}^{13}$CO, C${}^{18}$O, and CS. This difference is probably caused by the unique formation and destruction mechanisms of CH${}_3$OH.

21 pages, 4 figures, accepted for publication to PASJ

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Cited by in corpus (14)

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• A Multi-Transition Study of Molecules toward NGC 1068 based on High-Resolution Imaging Observations with ALMA
• A statistical study of giant molecular clouds traced by ${}^{13}$CO, C${}^{18}$O, CS, and CH${}_3$OH in the disk of NGC 1068 based on ALMA observations
• Diverse nuclear star-forming activities in the heart of NGC 253 resolved with ten-pc scale ALMA images
• A molecular line survey toward the nearby galaxies NGC 1068, NGC 253, and IC 342 at 3 mm with the Nobeyama 45 m radio telescope: The data
• ALMA Observations of Atomic Carbon [C I] (${{}^3\mathrm{P}}_1\to {{}^3\mathrm{P}}_0$) and Low-$J$ CO Lines in the Starburst Galaxy NGC 1808
• Spatially resolved star-formation relations of dense molecular gas in NGC 1068
• Merger-induced Shocks in the Nearby LIRG VV 114 through Methanol Observations with ALMA
• Sulfur-bearing species in molecular clouds
• A 3 mm Spectral Line Survey toward the Barred Spiral Galaxy NGC 3627
• λ = 2 mm spectroscopy observations toward the circumnuclear disk of NGC 1068