Dense Gas in the Outer Spiral Arm of M51
| dc.contributor.author | CHEN, Hao | |
| hal.structure.identifier | FORMATION STELLAIRE 2017 | |
| dc.contributor.author | BRAINE, J. | |
| hal.structure.identifier | Chinese Academy of Sciences [Changchun Branch] [CAS] | |
| dc.contributor.author | GAO, Yu | |
| dc.contributor.author | KODA, Jin | |
| hal.structure.identifier | Institut National des Sciences Appliquées - Rennes [INSA Rennes] | |
| dc.contributor.author | GU, Qiusheng | |
| dc.date.issued | 2017 | |
| dc.identifier.issn | 0004-637X | |
| dc.description.abstractEn | There is a linear relation between the mass of dense gas, traced by the HCN(1-0) luminosity, and the star formation rate (SFR), traced by the far-infrared luminosity. Recent observations of galactic disks have shown some systematic variations. In order to explore the SFR-dense gas link at high resolution ($\sim 4"$, $\sim 150$ pc) in the outer disk of an external galaxy, we have mapped a region about 5 kpc from the center along the northern spiral arm of M51 in the HCN(1-0), HCO$^+$(1-0) and HNC(1-0) emission lines using the Northern Extended Millimeter Array (NOEMA) interferometer. The HCN and HCO$^+$ lines were detected in 6 giant molecular associations (GMAs) while HNC emission was only detected in the two brightest GMAs. One of the GMAs hosts a powerful HII region and HCN is stronger than HCO$^+$ there. Comparing with observations of GMAs in the disks of M31 and M33 at similar angular resolution ($\sim 100$ pc), we find that GMAs in the outer disk of M51 are brighter in both HCN and HCO$^+$ lines by a factor of 3 on average. However, the $I_{HCN}/I_{CO}$ and $I_{HCO^+}/I_{CO}$ ratios are similar to the ratios in nearby galactic disks and the Galactic plane. Using the Herschel 70 $\mu$m data to trace the total IR luminosity at the resolution of the GMAs, we find that both the L$_{IR}$-L$_{HCN}$ and L$_{IR}$-L$_{HCO^+}$ relations in the outer disk GMAs are consistent with the proportionality between the L$_{IR}$ and the dense gas mass established globally in galaxies within the scatter. The IR/HCN and IR/HCO$^+$ ratios of the GMAs vary by a factor of 3, probably depending on whether massive stars are forming or not. | |
| dc.language.iso | en | |
| dc.publisher | American Astronomical Society | |
| dc.subject.en | Astrophysics - Astrophysics of Galaxies | |
| dc.title.en | Dense Gas in the Outer Spiral Arm of M51 | |
| dc.type | Article de revue | |
| dc.identifier.doi | 10.3847/1538-4357/836/1/101 | |
| dc.subject.hal | Planète et Univers [physics]/Astrophysique [astro-ph]/Astrophysique galactique [astro-ph.GA] | |
| dc.identifier.arxiv | 1612.00459 | |
| bordeaux.journal | The Astrophysical Journal | |
| bordeaux.page | id. 101 | |
| bordeaux.volume | 836 | |
| bordeaux.issue | 1 | |
| bordeaux.peerReviewed | oui | |
| hal.identifier | hal-01409623 | |
| hal.version | 1 | |
| hal.popular | non | |
| hal.audience | Internationale | |
| hal.origin.link | https://hal.archives-ouvertes.fr//hal-01409623v1 | |
| bordeaux.COinS | ctx_ver=Z39.88-2004&rft_val_fmt=info:ofi/fmt:kev:mtx:journal&rft.jtitle=The%20Astrophysical%20Journal&rft.date=2017&rft.volume=836&rft.issue=1&rft.spage=id.%20101&rft.epage=id.%20101&rft.eissn=0004-637X&rft.issn=0004-637X&rft.au=CHEN,%20Hao&BRAINE,%20J.&GAO,%20Yu&KODA,%20Jin&GU,%20Qiusheng&rft.genre=article |
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