Relationship between the Line Width of the Atomic and Molecular ISM in M33
| dc.contributor.author | KOCH, Eric | |
| dc.contributor.author | ROSOLOWSKY, Erik | |
| hal.structure.identifier | Caltech Division of Geological and Planetary Sciences | |
| dc.contributor.author | SCHRUBA, Andreas | |
| dc.contributor.author | LEROY, Adam | |
| dc.contributor.author | KEPLEY, Amanda | |
| hal.structure.identifier | FORMATION STELLAIRE 2019 | |
| dc.contributor.author | BRAINE, J. | |
| dc.contributor.author | DALCANTON, Julianne | |
| dc.contributor.author | JOHNSON, Megan | |
| dc.date.issued | 2019-02-17 | |
| dc.identifier.issn | 0035-8711 | |
| dc.description.abstractEn | We investigate how the spectral properties of atomic (H I) and molecular (H2) gas, traced by CO(2-1), are related in M33 on 80 pc scales. We find the H I and CO(2-1) velocity at peak intensity to be highly correlated, consistent with previous studies. By stacking spectra aligned to the velocity of H I peak intensity, we find that the CO line width (σHWHM = 4.6 ± 0.9 km s-1; σHWHM is the effective Gaussian width) is consistently smaller than the H I line width (σHWHM = 6.6 ± 0.1 km s-1), with a ratio of ˜0.7, in agreement with Druard et al. (2014). The ratio of the line widths remains less than unity when the data are smoothed to a coarser spatial resolution. In other nearby galaxies, this line width ratio is close to unity which has been used as evidence for a thick, diffuse molecular disk that is distinct from the thin molecular disk dominated by molecular clouds. The smaller line width ratio found here suggests that M33 has a marginal thick molecular disk. From modelling individual lines-of-sight, we recover a strong correlation between H I and CO line widths when only the H I located closest to the CO component is considered. The median line width ratio of the line-of-sight line widths is 0.56 ± 0.01. There is substantial scatter in the H I-CO(2-1) line width relation, larger than the uncertainties, that results from regional variations on <500 pc scales, and there is no significant trend in the line widths, or their ratios, with galactocentric radius. These regional line width variations may be a useful probe of changes in the local cloud environment or the evolutionary state of molecular clouds. | |
| dc.language.iso | en | |
| dc.publisher | Oxford University Press (OUP): Policy P - Oxford Open Option A | |
| dc.title.en | Relationship between the Line Width of the Atomic and Molecular ISM in M33 | |
| dc.type | Article de revue | |
| dc.identifier.doi | 10.1093/mnras/stz484 | |
| dc.subject.hal | Planète et Univers [physics]/Astrophysique [astro-ph]/Astrophysique galactique [astro-ph.GA] | |
| dc.identifier.arxiv | 1902.05007 | |
| bordeaux.journal | Monthly Notices of the Royal Astronomical Society | |
| bordeaux.volume | 485 | |
| bordeaux.issue | 2324-2342 | |
| bordeaux.peerReviewed | oui | |
| hal.identifier | hal-02051728 | |
| hal.version | 1 | |
| hal.popular | non | |
| hal.audience | Internationale | |
| hal.origin.link | https://hal.archives-ouvertes.fr//hal-02051728v1 | |
| bordeaux.COinS | ctx_ver=Z39.88-2004&rft_val_fmt=info:ofi/fmt:kev:mtx:journal&rft.jtitle=Monthly%20Notices%20of%20the%20Royal%20Astronomical%20Society&rft.date=2019-02-17&rft.volume=485&rft.issue=2324-2342&rft.eissn=0035-8711&rft.issn=0035-8711&rft.au=KOCH,%20Eric&ROSOLOWSKY,%20Erik&SCHRUBA,%20Andreas&LEROY,%20Adam&KEPLEY,%20Amanda&rft.genre=article |
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