Rie Miura

NRO M 33 All-Disk Survey of Giant Molecular Clouds (NRO MAGiC). I. H I to H2 Transition

We present the results of the Nobeyama Radio Observatory (NRO) M 33 All-Disk (30 0 � 30 0 or 7.3 kpc � 7.3 kpc) Survey of Giant Molecular Clouds (NRO MAGiC) based on 12 CO (J = 1–0) observations using the NRO 45 m telescope. The spatial resolution of the resultant map is 19: 3, corresponding to 81 pc, which is sufficient to identify each Giant Molecular Cloud (GMC) in the disk. We found clumpy structures with a typical spatial scale of � 100 pc, corresponding to GMCs, and no diffuse, smoothly distributed component of molecular gas at this sensitivity. The overall distribution of molecular gas roughly agrees with that of H I. However, a closer inspection of the CO and H I maps suggests that not every CO emission is associated with local H I peaks, particularly in the inner portion of the disk ( r< 2 kpc), although most of the CO emission is located at the local H I peaks in the outer radii. We found that most uncovered GMCs are accompanied by massive star-forming regions, although the star-formation rates (SFRs) vary widely from cloud to cloud. The surface density of the azimuthally averaged H I gas exhibits a flat radial distribution. However, the CO radial distribution shows a significant enhancement within the central 1–2 kpc region, which is very similar to that of the SFR. We obtained a map of the molecular fraction, fmol =Σ H2 =(ΣH I +Σ H2 ), with a resolution of 100 pc. This is the first fmol map covering an entire galaxy with a GMC-scale resolution. We found that fmol tends to be high near the center. The correlation between fmol and gas surface density shows two distinct sequences. The presence of two correlation sequences can be explained by a difference of metallicity; i.e., higher (� 2-fold) metallicity in the central region ( r< 1.5 kpc) than in the outer parts. Alternatively, difference in the scale height can also account for the two sequences; i.e., the scale height increases at the outer disk.

Enhancement of CO(3-2)/CO(1-0) ratios and star formation efficiencies in supergiant H II regions

We present evidence that super giant HII regions (GHRs) and other disk regions of the nearby spiral galaxy, M33, occupy distinct locations in the correlation between molecular gas,

Temperature Variations of Cold Dust in the Triangulum Galaxy M 33

\Sigma_{\rm H_2}

Tests of star formation metrics in the low metallicity galaxy NGC 5253 using ALMA observations of H30 line emission

, and the star formation rate surface density,

13CO(J = 1–0) On-the-Fly Mapping of the Giant H II Region NGC 604: Variation in Molecular Gas Density and Temperature due to Sequential Star Formation

\Sigma_{\rm SFR}

NRO M 33 All-Disk Survey of Giant Molecular Clouds (NRO MAGiC). II Dense Gas Formation

. This result is based on wide field and high sensitivity CO(3-2) observations at 100 pc resolution. Star formation efficiencies (SFE), defined as

ASTE CO(3-2) Observations of the Southern Barred Spiral Galaxy NGC 986: a Large Gaseous Bar Filled with a Dense Molecular Medium

\Sigma_{\rm SFR}

ALMA Observations toward the Starburst Dwarf Galaxy NGC 5253. I. Molecular Cloud Properties and Scaling Relations

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Molecular Gas and Star Formation Properties in Early Stage Mergers: SMA CO(2-1) Observations of the LIRGs NGC 3110 and NGC 232

\Sigma_{\rm H_2}

Gas, dust, stars, star formation, and their evolution in M 33 at giant molecular cloud scales

, in GHRs are found to be about 1 dex higher than in other disk regions. The CO(3-2)/CO(1-0) integrated intensity ratio is also higher than the average over the disk. Such high SFE and CO(3-2)/CO(1-0) can reach the values found in starburst galaxies, which suggests that GHRs may be the elements building up a larger scale starburst region. Three possible contributions to high SFEs in GHR are investigated: (1) the