ALMA multiline observations toward the central region of NGC 613

Abstract

We report ALMA observations of molecular gas and continuum emission in the 90 and 350 GHz bands toward a nearby Seyfert galaxy NGC 613. Radio continuum emissions were detected at 95 and 350 GHz from both the circum-nuclear disk (CND) ($r\le 90$ pc) and a star-forming ring (250 pc $\le r\le 340$ pc), and the 95 GHz continuum was observed to extend from the center at a position angle of $20^{\circ }\pm 8^{\circ }$. The archival 4.9 GHz data and our 95 GHz data show spectral indices of $\alpha \le -0.6$ and $-0.2$ along the jets and in the star-forming ring; these can be produced by synchrotron emission and free-free emission, respectively. In addition, we detected the emission of CO(3-2), HCN(1-0), HCN(4-3), HCO${}^{+}$(1-0), HCO${}^{+}$(4-3), CS(2-1), and CS(7-6) in both the CND and ring. The rotational temperatures and column densities of molecules derived from $J=1-0$ and $4-3$ lines of HCN and HCO${}^{+}$ and $J=2-1$ and $7-6$ of CS in the CND and ring were derived. Furthermore, a non-LTE model revealed that the kinetic temperature of $T_{\mathrm{k}}=350-550$ K in the CND is higher than $T_{\mathrm{k}}=80-300$ K in the ring, utilizing the intensity ratios of HCN, HCO${}^{+}$, and CS. The star-formation efficiency in the CND is almost an order of magnitude lower than those at the spots in the star-forming ring, while the dominant activity of the central region is the star formation rather than active galactic nuclei. We determined that the large velocity dispersion of CO extending toward the north side of the CND and decomposing into blueshifted and redshifted features is probably explained by the effect of the radio jets. These results strongly suggest that the jets heat the gas in the CND, in which the feedback prevents star formation.

37 pages, 22 figures, 6tables, Accepted for publication in PASJ

References in corpus (13)

• The Critical Density and the Effective Excitation Density of Commonly Observed Molecular Dense Gas Tracers
• Molecular line emission in NGC1068 imaged with ALMA. I An AGN-driven outflow in the dense molecular gas
• A multi-transition HCN and HCO+ study of 12 nearby active galaxies: AGN versus SB environments
• A 2 mm spectral line survey of the starburst galaxy NGC 253
• Molecular line emission in NGC1068 imaged with ALMA: II. The chemistry of the dense molecular gas
• A SINFONI view of Galaxy Centers: Morphology and Kinematics of five Nuclear Star Formation Rings
• ALMA Imaging of HCN, CS and dust in Arp 220 and NGC 6240
• Ethynyl (C2H) in massive star formation: Tracing the initial conditions?
• Multi-molecule ALMA observations towards the Seyfert 1 galaxy NGC 1097
• Submillimeter-HCN Diagram for an Energy Diagnostics in the Centers of Galaxies
• Optical Depth Estimates and Effective Critical Densities of Dense Gas Tracers in the Inner Parts of Nearby Galaxy Discs
• The unbearable opaqueness of Arp 220
• Thick Disks, and an Outflow, of Dense Gas in the Nuclei of Nearby Seyfert Galaxies

Cited by in corpus (12)

• ALMA observations of molecular tori around massive black holes
• GASP. XXII The molecular gas content of the JW100 jellyfish galaxy at z~0.05: does ram pressure promote molecular gas formation?
• ALMA captures feeding and feedback from the active galactic nucleus in NGC613
• Dense molecular gas in the starburst nucleus of NGC 1808
• ALMA [CI] observations toward the central region of a Seyfert galaxy NGC 613
• Understanding if molecular ratios can be used as diagnostics of AGN and starburst activity: The case of NGC 1068
• The nuclear region of NGC 613. I -- Multiwavelength analysis
• A multi-scale investigation into the diagnostic potential of the HCN/HCO${}^{+}$ ratio for AGN and starburst activity in nearby galaxies
• The nuclear region of NGC 613 -- II. Kinematics and stellar archaeology
• Molecular gas dynamics around nuclei of galaxies
• X-ray and CO-Derived Column Densities in AGN: A Study of Obscuration Properties in CTAGN and Non-CTAGN
• High resolution mapping of molecular tori with ALMA