Radio Continuum Observations of Local Star-Forming Galaxies Using the Caltech Continuum Backend on the Green Bank Telescope

Rabidoux, K.; Pisano, D. J.; Kepley, Amanda A.; Johnson, K. E.; Balser, Dana S.

doi:10.1088/0004-637x/780/1/19

Cited by 16 publications

(18 citation statements)

References 47 publications

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“…In fact, the 0.19 dex in dispersion we observed for q 33 is similar to that found in Condon et al (1991) at 1.49 GHz. The tighter dispersion found for our global measurements compared to the local ones of Rabidoux et al (2014) appears to corroborate the global nature of the IR-radio correlation. Note as well that q 32.5 GHz does not appear to correlate with SFR S .…”

Section: Nature Of the 33ghz Radio Emissionsupporting

confidence: 81%

A 33 GHz Survey of Local Major Mergers: Estimating the Sizes of the Energetically Dominant Regions from High-resolution Measurements of the Radio Continuum

Barcos-Muñoz

Leroy

Evans

et al. 2017

ApJ

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We present Very Large Array observations of the 33 GHz radio continuum emission from 22 local ultraluminous and luminous infrared (IR) galaxies (U/LIRGs). These observations have spatial (angular) resolutions of 30-720pc (0 07-0 67) in a part of the spectrum that is likely to be optically thin. This allows us to estimate the size of the energetically dominant regions. We find half-light radii from 30pc to 1.7kpc. The 33 GHz flux density correlates well with the IR emission, and we take these sizes as indicative of the size of the region that produces most of the energy. Combining our 33 GHz sizes with unresolved measurements, we estimate the IR luminosity and star formation rate per area and the molecular gas surface and volume densities. These quantities span a wide range (4 dex) and include some of the highest values measured for any galaxy (e.g.,  -). Consistent with previous work, contrasting these data with observations of normal disk galaxies suggests a nonlinear and likely multivalued relation between star formation rate and molecular gas surface density, though this result depends on the adopted CO-to-H 2 conversion factor and the assumption that our 33 GHz sizes apply to the gas. Eleven sources appear to exceed the luminosity surface density predicted for starbursts supported by radiation pressure and supernova feedback; however, we note the need for more detailed observations of the inner disk structure. U/LIRGs with higher surface brightness exhibit stronger [C II] 158 μm deficits, consistent with the suggestion that high energy densities drive this phenomenon.

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Section: Nature Of the 33ghz Radio Emissionsupporting

confidence: 81%

A 33 GHz Survey of Local Major Mergers: Estimating the Sizes of the Energetically Dominant Regions from High-resolution Measurements of the Radio Continuum

Barcos-Muñoz

Leroy

Evans

et al. 2017

ApJ

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“…Using Eq. 2 and assuming an H II dominated [C II] luminosity this corresponds to star formation rates between 0.16 and 0.65 M yr −1 within the central 500 pc, similar to the range of 0.4-0.6 M yr −1 derived byRabidoux et al (2014). If we assume that the [C II] luminosity is produced not only in the ionized gas, but stems from all phases, we find significantly lower star formation rates of 0.03 and 0.13 M yr −1 .…”

supporting

confidence: 81%

“…Gas flows along the spiral arms onto the nuclear ring, triggering star formation at the rate of ∼ 0.1M yr −1 . Recently, Rabidoux et al (2014) used thermal and nonthermal 33 GHz luminosities to derive star formation rates of 0.4-0.6 M yr −1 within the central 23 . The volume inside the ring is dominated by the massive central nuclear star cluster.…”

Section: Kinematics In the Nucleus Of Ic 342mentioning

confidence: 99%

[CII] 158$μ$m and [NII] 205$μ$m emission from IC 342 - Disentangling the emission from ionized and photo-dissociated regions

Röllig,

Simon,

Güsten

et al. 2016

Preprint

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Context. Atomic fine-structure line emission is a major cooling process in the interstellar medium (ISM). In particular the [C II] 158µm line is one of the dominant cooling lines in photon-dominated regions (PDRs). However, it is not confined to PDRs but can also originate from the ionized gas closely surrounding young massive stars. The proportion of the [C II] emission from H II regions relative to that from PDRs can vary significantly. Aims. We investigate the question of how much of the [C II] emission in the nucleus of the nearby spiral galaxy IC 342 is contributed by PDRs and by the ionized gas. We examine the spatial variations of starburst/PDR activity and study the correlation of the [C II] line with the [N II] 205µm emission line coming exclusively from the H II regions. Methods. We present small maps of [C II] 158µm and [N II] 205µm lines recently observed with the GREAT receiver on board SOFIA. We present different methods to utilize the superior spatial and spectral resolution of our new data to infer information on how the gas kinematics in the nuclear region influence the observed line profiles. In particular we present a super-resolution method to derive how unresolved, kinematically correlated structures in the beam contribute to the observed line shapes. Results. We find that the emission coming from the ionized gas shows a kinematic component in addition to the general Doppler signature of the molecular gas. We interpret this as the signature of two bi-polar lobes of ionized gas expanding out of the galactic plane. We then show how this requires an adaptation of our understanding of the geometrical structure of the nucleus of IC 342.Examining the starburst activity we find ratios I([C II])/I( 12 CO(1 − 0)) between 400 and 1800 in energy units. Applying predictions from numerical models of H II and PDR regions to derive the contribution from the ionized phase to the total [C II] emission we find that 35-90% of the observed [C II] intensity stems from the ionized gas if both phases contribute. Averaged over the central few hundred parsec we find for the [C II] contribution a H II-to-PDR ratio of 70:30. Conclusions. The ionized gas in the center of IC 342 contributes more strongly to the overall [C II] emission than is commonly observed on larger scales and than is predicted. Kinematic analysis shows that the majority of the [C II] emission is related to the strong but embedded star formation in the nuclear molecular ring and only marginally emitted from the expanding bi-polar lobes of ionized gas.

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“…Gas flows along the spiral arms onto the nuclear ring, triggering star formation at the rate of ∼0.1 M yr −1 . Recently, Rabidoux et al (2014) used thermal and nonthermal 33 GHz luminosities to derive star formation rates of 0.4−0.6 M yr −1 within the central 23 . The volume inside the ring is dominated by the massive central nuclear star cluster.…”

Section: Data Overviewmentioning

confidence: 99%

[C II] 158μm and [N II] 205μm emission from IC 342

Röllig

Simon

Güsten

et al. 2016

A&A

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Context. Atomic fine-structure line emission is a major cooling process in the interstellar medium (ISM). In particular the [C II] 158 µm line is one of the dominant cooling lines in photon-dominated regions (PDRs). However, it is not confined to PDRs but can also originate from the ionized gas closely surrounding young massive stars. observed with the GREAT receiver on board SOFIA.We present different methods to utilize the superior spatial and spectral resolution of our new data to infer information on how the gas kinematics in the nuclear region influence the observed line profiles. In particular we present a super-resolution method to derive how unresolved, kinematically correlated structures in the beam contribute to the observed line shapes. Results. We find that the emission coming from the ionized gas shows a kinematic component in addition to the general Doppler signature of the molecular gas. We interpret this as the signature of two bi-polar lobes of ionized gas expanding out of the galactic plane. We then show how this requires an adaptation of our understanding of the geometrical structure of the nucleus of IC 342. Examining the starburst activity we find ratios I([C II])/I( 12 CO(1−0)) between 400 and 1800 in energy units. Applying predictions from numerical models of H II and PDR regions to derive the contribution from the ionized phase to the total [C II] emission we find that 35−90% of the observed [C II] intensity stems from the ionized gas if both phases contribute. Averaged over the central few hundred parsec we find for the [C II] contribution a H II-to-PDR ratio of 70:30. Conclusions. The ionized gas in the center of IC 342 contributes more strongly to the overall [C II] emission than is commonly observed on larger scales and than is predicted. Kinematic analysis shows that the majority of the [C II] emission is related to the strong but embedded star formation in the nuclear molecular ring and only marginally emitted from the expanding bi-polar lobes of ionized gas.

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Radio Continuum Observations of Local Star-Forming Galaxies Using the Caltech Continuum Backend on the Green Bank Telescope

Cited by 16 publications

References 47 publications

A 33 GHz Survey of Local Major Mergers: Estimating the Sizes of the Energetically Dominant Regions from High-resolution Measurements of the Radio Continuum

A 33 GHz Survey of Local Major Mergers: Estimating the Sizes of the Energetically Dominant Regions from High-resolution Measurements of the Radio Continuum

[CII] 158$μ$m and [NII] 205$μ$m emission from IC 342 - Disentangling the emission from ionized and photo-dissociated regions

[C II] 158μm and [N II] 205μm emission from IC 342

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