CO(
                    <i>J</i>
                    = 1-0) IMAGING OF M51 WITH CARMA AND THE NOBEYAMA 45 m TELESCOPE

Koda, Jin; Sawada, Tsuyoshi; Wright, M. C. H.; Teuben, Peter; Corder, Stuartt; Patience, J.; Scoville, N. Z.; Meyer, Jennifer Donovan; Egusa, Fumi

doi:10.1088/0067-0049/193/1/19

Cited by 70 publications

(112 citation statements)

References 24 publications

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“…As a test of our calibration strategy, we compared the flux within the hybrid synthesis data cube with recent CO surveys of M51 by BIMA (Helfer et al 2003) and CARMA (Koda et al 2011). Although conceptually straightforward, this comparison must be done with care since each data set has different angular resolution, channel width, noise characteristics, and field of view.…”

Section: Flux Calibrationmentioning

confidence: 99%

THE PLATEAU DE BURE + 30 m ARCSECOND WHIRLPOOL SURVEY REVEALS A THICK DISK OF DIFFUSE MOLECULAR GAS IN THE M51 GALAXY

Pety

Schinnerer

Leroy

et al. 2013

ApJ

157

175

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We present the data of the Plateau de Bure Arcsecond Whirlpool Survey, a high spatial and spectral resolution 12 CO (1-0) line survey of the inner ∼10 × 6 kpc of the M51 system, and the first wide-field imaging of molecular gas in a star-forming spiral galaxy with resolution matched to the typical size of giant molecular clouds (40 pc). We describe the observation, reduction, and combination of the Plateau de Bure Interferometer (PdBI) and IRAM-30 m "short spacing" data. The final data cube attains 1. 1 resolution over the ∼270 × 170 field of view, with sensitivity to all spatial scales from the combination of PdBI and IRAM-30 m data, and a brightness sensitivity of 0.4 K (1σ ) in each 5 km s −1 -wide channel map. We find a CO luminosity of 9 × 10 8 K km s −1 pc 2 , corresponding to a molecular gas mass of 4 × 10 9 M for a standard CO-to-H 2 conversion factor. Unexpectedly, we find that a large fraction of this emission, (50 ± 10)%, arises mostly from spatial scales larger than 36 1.3 kpc. Through a series of tests, we demonstrate that this extended emission does not result from a processing artifact. We discuss its origin in light of the stellar component, the 12 CO/ 13 CO ratio, and the difference between the kinematics and structure of the PdBI-only and hybrid synthesis (PdBI + IRAM-30 m) images. The extended emission is consistent with a thick, diffuse disk of molecular gas with a typical scale height of ∼200 pc, substructured in unresolved filaments that fill ∼0.1% of the volume.

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Section: Flux Calibrationmentioning

confidence: 99%

THE PLATEAU DE BURE + 30 m ARCSECOND WHIRLPOOL SURVEY REVEALS A THICK DISK OF DIFFUSE MOLECULAR GAS IN THE M51 GALAXY

Pety

Schinnerer

Leroy

et al. 2013

ApJ

157

175

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“…As for M51a, the detailed information of the CARMA + NRO45 observations and data reduction is described in Koda et al (2009bKoda et al ( , 2011. At the final resolution of the combined map (3.…”

Section: Carma and Nro45 Co (J = 1-0) Datamentioning

confidence: 99%

THE SUPER-LINEAR SLOPE OF THE SPATIALLY RESOLVED STAR FORMATION LAW IN NGC 3521 AND NGC 5194 (M51a)

Liu

Koda

Calzetti

et al. 2011

ApJ

Self Cite

132

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We have conducted interferometric observations with the Combined Array for Research in Millimeter Astronomy (CARMA) and an on-the-fly mapping with the 45 m telescope at Nobeyama Radio Observatory (NRO45) in the CO (J = 1-0) emission line of the nearby spiral galaxy NGC 3521. Using the new combined CARMA + NRO45 data of NGC 3521, together with similar data for NGC 5194 (M51a) and archival SINGS Hα, 24 μm THINGS H i, and Galaxy Evolution Explorer/Far-UV (FUV) data for these two galaxies, we investigate the empirical scaling law that connects the surface density of star formation rate (SFR) and cold gas (known as the Schmidt-Kennicutt law or S-K law) on a spatially resolved basis and find a super-linear slope for the S-K law when carefully subtracting the background emissions in the SFR image. We argue that plausibly deriving SFR maps of nearby galaxies requires the diffuse stellar and dust background emission to be subtracted carefully (especially in the mid-infrared and to a lesser extent in the FUV). Applying this approach, we perform a pixel-by-pixel analysis on both galaxies and quantitatively show that the controversial result whether the molecular S-K law (expressed as) is super-linear or basically linear is a result of removing or preserving the local background. In both galaxies, the power index of the molecular S-K law is super-linear (γ H 2 1.5) at the highest available resolution (∼230 pc) and decreases monotonically for decreasing resolution. We also find in both galaxies that the scatter of the molecular S-K law (σ H 2 ) monotonically increases as the resolution becomes higher, indicating a trend for which the S-K law breaks down below some scale. Both γ H 2 and σ H 2 are systematically larger in M51a than in NGC 3521, but when plotted against the de-projected scale (δ dp ), both quantities become highly consistent for the two galaxies, tentatively suggesting that the sub-kpc molecular S-K law in spiral galaxies depends only on the scale being considered, without varying among spiral galaxies. A logarithmic function γ H 2 = −1.1 log[δ dp /kpc] + 1.4 and a linear relation σ H 2 = −0.2[δ dp /kpc] + 0.7 are obtained through fitting to the M51a data, which describes both galaxies impressively well on sub-kpc scales. A larger sample of galaxies with better sensitivity, resolution, and broader field of view are required to test the general applicability of these relations.

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“…Nevertheless, 3 galaxies in our sample have adequate CO(3−2) maps to further our study. As part of the JCMT Nearby Galaxies Legacy Survey (Wilson et al 2009 Koda et al (2011) have published a high-resolution single-dish CO(1−0) map which we adopt. Additional CO(1−0) observations of several galaxies in the sample have been published by Kuno et al (2007).…”

Section: Appendix D: Impact Of Different Co Transitionsmentioning

confidence: 99%

Towards understanding the relation between the gas and the attenuation in galaxies at kpc scales

Boquien

Boselli

Buat

et al. 2013

A&A

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Context. Understanding the relation between the attenuation and the gas is fundamental for interpreting the appearance of galaxies. This can now be done down to a local scale in the local Universe, thanks to the high spatial resolution achievable from the farultraviolet (FUV) to the far-infrared (FIR). More importantly, this relation is also crucial for predicting the emission of galaxies. This is essential in semi-analytic models that link dark matter from large cosmological simulations, to the baryonic matter which we can observe directly. Aims. The aim of the present paper is to provide new and more detailed relations at the kpc scale between the gas surface density and the face-on optical depth directly calibrated on galaxies, in order to compute the attenuation not only for semi-analytic models, but also for observational models as new and upcoming radio observatories are able to trace gas ever farther away in the Universe. Methods. We have selected a sample of 4 nearby resolved galaxies and a sample of 27 unresolved galaxies from the Herschel Reference Survey and the Very Nearby Galaxies Survey, for which we have a large set of multi-wavelength data from the FUV to the FIR including metallicity gradients for resolved galaxies, along with radio HI and CO observations. For each pixel in resolved galaxies and for each galaxy in the unresolved sample, we compute the face-on optical depth from the attenuation determined with the CIGALE spectral energy distribution fitting code and an assumed geometry. We determine the gas surface density from HI and CO observations with a metallicity-dependent X CO factor. Results. We provide new, simple-to-use relations to determine the face-on optical depth from the gas surface density, taking the metallicity into account, which proves to be crucial for a proper estimate. The method used to determine the gas surface density or the face-on optical depth has little impact on the relations except for galaxies that have an inclination over 50• . Finally, we provide detailed instructions on how to efficiently compute the attenuation from the gas surface density taking into account possible information on the metallicity. Conclusions. Examination of the influence of these new relations on simulated FUV and IR luminosity functions shows a clear impact compared to older, more-frequently used relations, which in turn could affect the conclusions drawn from studies based on large-scale cosmological simulations.

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CO( J = 1-0) IMAGING OF M51 WITH CARMA AND THE NOBEYAMA 45 m TELESCOPE

Cited by 70 publications

References 24 publications

THE PLATEAU DE BURE + 30 m ARCSECOND WHIRLPOOL SURVEY REVEALS A THICK DISK OF DIFFUSE MOLECULAR GAS IN THE M51 GALAXY

THE PLATEAU DE BURE + 30 m ARCSECOND WHIRLPOOL SURVEY REVEALS A THICK DISK OF DIFFUSE MOLECULAR GAS IN THE M51 GALAXY

THE SUPER-LINEAR SLOPE OF THE SPATIALLY RESOLVED STAR FORMATION LAW IN NGC 3521 AND NGC 5194 (M51a)

Towards understanding the relation between the gas and the attenuation in galaxies at kpc scales

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