All‐Sky 4.85 GHz Flux Measurements of H<scp>ii</scp>Regions

Kuchar, T. A.; Clark, F. O.

doi:10.1086/304697

Cited by 110 publications

(136 citation statements)

References 14 publications

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“…Directly south of W 28, the ultracompact HII region W 28A2 is a prominent radio source, and is positioned within 0.1 • of the centroid of HESS J1800−240B. The other HII regions G6.1−0.6 (Kuchar & Clark 1997) and 6.225−0.569 (Lockman 1989) are also associated with radio emission.…”

Section: Nanten and Other Observations Of Molecular Cloudsmentioning

confidence: 95%

Discovery of very high energy gamma-ray emission coincident with molecular clouds in the W 28 (G6.4-0.1) field

Aharonian

Akhperjanian

Bazer‐Bachi

et al. 2008

A&A

239

238

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Aims. Observations of shell-type supernova remnants (SNRs) in the GeV to multi-TeV γ-ray band, coupled with those at millimetre radio wavelengths, are motivated by the search for cosmic-ray accelerators in our Galaxy. The old-age mixed-morphology SNR W 28 (distance ∼2 kpc) is a prime target due to its interaction with molecular clouds along its northeastern boundary and other clouds situated nearby. Methods. We observed the W 28 field (for ∼40 h) at very high energy (VHE) γ-ray energies (E > 0.1 TeV) with the HESS. Cherenkov telescopes. A reanalysis of EGRET E > 100 MeV data was also undertaken. Results from the NANTEN 4 m telescope Galactic plane survey and other CO observations were used to study molecular clouds. Results. We have discovered VHE γ-ray emission (HESS J1801−233) coincident with the northeastern boundary of W 28 and a complex of sources (HESS J1800−240A, B and C) ∼0.5 • south of W 28 in the Galactic disc. The EGRET source (GRO J1801−2320) is centred on HESS J1801−233 but may also be related to HESS J1800−240 given the large EGRET point spread function. The VHE differential photon spectra are well fit by pure power laws with indices Γ ∼ 2.3 to 2.7. The spectral indices of HESS J1800−240A, B, and C are consistent within statistical errors. All VHE sources are ∼10 in intrinsic radius except for HESS J1800−240C, which appears pointlike. The NANTEN 12 CO(J = 1−0) data reveal molecular clouds positionally associating with the VHE emission, spanning a ∼15 km s −1 range in local standard of rest velocity. Conclusions. The VHE/molecular cloud association could indicate a hadronic origin for HESS J1801−233 and HESS J1800−240, and several cloud components in projection may contribute to the VHE emission. The clouds have components covering a broad velocity range encompassing the distance estimates for W 28 (∼2 kpc) and extending up to ∼4 kpc. Assuming hadronic origin and distances of 2 and 4 kpc for cloud components, the required cosmic-ray density enhancement factors (with respect to the solar value) are in the range ∼10 to ∼30. If situated at 2 kpc distance, such cosmic-ray densities may be supplied by SNRs like W 28. Additionally and/or alternatively, particle acceleration may come from several catalogued SNRs and SNR candidates, the energetic ultra compact HII region W 28A2, and the HII regions M 8 and M 20, along with their associated open clusters. Further sub-mm observations would be recommended to probe in detail the dynamics of the molecular clouds at velocites >10 km s −1 and their possible connection to W 28. Key words. gamma rays: observationsEnergy spectra are only available in electronic form at

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Section: Nanten and Other Observations Of Molecular Cloudsmentioning

confidence: 95%

Discovery of very high energy gamma-ray emission coincident with molecular clouds in the W 28 (G6.4-0.1) field

Aharonian

Akhperjanian

Bazer‐Bachi

et al. 2008

A&A

239

238

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“…The radio nebula list was compiled from: G -Reifenstad III et al (1970), Downes et al (1980), Lockman (1989) and Kuchar & Clark (1997), CTB -Wilson & Bolton (1960) and Wilson (1963), andW -Westerhout (1958). We also indicate some infrared nebulae related to sources in the AFGL and IRAS catalogues.…”

Section: Search Methodsmentioning

confidence: 99%

New infrared star clusters in the Northern and Equatorial Milky Way with 2MASS

Bica

Dutra

Soares

et al. 2003

A&A

201

216

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Abstract. We carried out a survey of infrared star clusters and stellar groups on the 2MASS J, H and K s all-sky release Atlas in the Northern and Equatorial Milky Way (350The search in this zone complements that in the Southern Milky Way (Dutra et al. 2003a). The method concentrates efforts on the directions of known optical and radio nebulae. The present study provides 167 new infrared clusters, stellar groups and candidates. Combining the two studies for the whole Milky Way, 346 infrared clusters, stellar groups and candidates were discovered, whereas 315 objects were previously known. They constitute an important new sample for future detailed studies.

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“…The source IRAS 16070−5107 is associated with a clump in the field of G331. One clump is associated with the radio continuum source G331.4+00.0, which was observed in an all-sky survey of HII regions at 4.85 GHz (Kuchar & Clark 1997). We retrieved C 18 O (1-0) data from the Three-mm Ultimate Mopra Milky way Survey (ThrUMMS 6 ) and found that the emission in the lower left-hand corner in G331 (see Fig.…”

Section: Comments On Individual Irdcs (Based On Gaussclumps)mentioning

confidence: 96%

The mass distribution of clumps within infrared dark clouds. A Large APEX Bolometer Camera study

Gómez

Wyrowski

Schüller

et al. 2014

A&A

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Aims. We present an analysis of the dust continuum emission at 870 μm in order to investigate the mass distribution of clumps within infrared dark clouds (IRDCs). Methods. We map six IRDCs with the Large APEX BOlometer CAmera (LABOCA) at APEX, reaching an rms noise level of σ rms = 28 -44 mJy beam −1 . The dust continuum emission coming from these IRDCs was decomposed by using two automated algorithms, Gaussclumps and Clumpfind. Moreover, we carried out single-pointing observations of the N 2 H + (3-2) line toward selected positions to obtain kinematic information. Results. The mapped IRDCs are located in the range of kinematic distances of 2.7-3.2 kpc. We identify 510 and 352 sources with Gaussclumps and Clumpfind, respectively, and estimate masses and other physical properties assuming a uniform dust temperature. The mass ranges are 6-2692 M (Gaussclumps) and 7-4254 M (Clumpfind), and the ranges in effective radius are ∼0.10-0.74 pc (Gaussclumps) and 0.16-0.99 pc (Clumpfind). The mass distribution, independent of the decomposition method used, is fitted by a power law, dN/dM ∝ M α , with an index (α) of −1.60 ± 0.06, consistent with the CO mass distribution and other high-mass star-forming regions.

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All‐Sky 4.85 GHz Flux Measurements of HiiRegions

Cited by 110 publications

References 14 publications

Discovery of very high energy gamma-ray emission coincident with molecular clouds in the W 28 (G6.4-0.1) field

Discovery of very high energy gamma-ray emission coincident with molecular clouds in the W 28 (G6.4-0.1) field

New infrared star clusters in the Northern and Equatorial Milky Way with 2MASS

The mass distribution of clumps within infrared dark clouds. A Large APEX Bolometer Camera study

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