0
views
0
recommends
+1 Recommend
0 collections
    0
    shares
      • Record: found
      • Abstract: found
      • Article: not found

      A 2–3 mm high-resolution molecular line survey towards the centre of the nearby spiral galaxy NGC 6946

      Read this article at

      Bookmark
          There is no author summary for this article yet. Authors can add summaries to their articles on ScienceOpen to make them more accessible to a non-specialist audience.

          Abstract

          The complex physical, kinematic, and chemical properties of galaxy centres make them interesting environments to examine with molecular line emission. We present new 2 − 4″ (∼75 − 150 pc at 7.7 Mpc) observations at 2 and 3 mm covering the central 50″ (∼1.9 kpc) of the nearby double-barred spiral galaxy NGC 6946 obtained with the IRAM Plateau de Bure Interferometer. We detect spectral lines from ten molecules: CO, HCN, HCO +, HNC, CS, HC 3N, N 2H +, C 2H, CH 3OH, and H 2CO. We complemented these with published 1 mm CO observations and 33 GHz continuum observations to explore the star formation rate surface density Σ SFRon 150 pc scales. In this paper, we analyse regions associated with the inner bar of NGC 6946 – the nuclear region (NUC), the northern (NBE), and southern inner bar end (SBE) and we focus on short-spacing corrected bulk (CO) and dense gas tracers (HCN, HCO +, and HNC). We find that HCO +correlates best with Σ SFR, but the dense gas fraction ( f dense) and star formation efficiency of the dense gas (SFE dense) fits show different behaviours than expected from large-scale disc observations. The SBE has a higher Σ SFR, f dense, and shocked gas fraction than the NBE. We examine line ratio diagnostics and find a higher CO(2−1)/CO(1−0) ratio towards NBE than for the NUC. Moreover, comparison with existing extragalactic datasets suggests that using the HCN/HNC ratio to probe kinetic temperatures is not suitable on kiloparsec and sub-kiloparsec scales in extragalactic regions. Lastly, our study shows that the HCO +/HCN ratio might not be a unique indicator to diagnose AGN activity in galaxies.

          Related collections

          Most cited references152

          • Record: found
          • Abstract: not found
          • Article: not found

          Astropy: A community Python package for astronomy

            Bookmark
            • Record: found
            • Abstract: not found
            • Article: not found

            Star Formation in the Milky Way and Nearby Galaxies

              Bookmark
              • Record: found
              • Abstract: not found
              • Article: not found

              Binary Companions of Evolved Stars in APOGEE DR14: Search Method and Catalog of ∼5000 Companions

                Bookmark

                Author and article information

                Journal
                Astronomy & Astrophysics
                A&A
                EDP Sciences
                0004-6361
                1432-0746
                March 2022
                March 23 2022
                March 2022
                : 659
                : A173
                Article
                10.1051/0004-6361/202142624
                b4749153-5c65-455f-8a4a-1677e7c44638
                © 2022

                https://www.edpsciences.org/en/authors/copyright-and-licensing

                History

                Comments

                Comment on this article