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Triggered star formation around HII regions could be an important process. The Galactic HII region RCW 79 is a prototypical object for triggered high-mass star formation. We take advantage of Herschel data from the surveys HOBYS, "Evolution…

We present a survey of 56 massive star-forming regions in the 44 GHz methanol maser transition made with the Karl G. Jansky Very Large Array (VLA); 24 of the 56 fields showed maser emission. The data allow us to demonstrate associations, at…

Star-forming regions are usually studied in the context of Galactic surveys, but dedicated observations are sometimes needed when the study reaches beyond the survey area. Here, we studied the G345.5+1.5 region, which is located slightly…

Astrophysics of Galaxies · Physics 2019-03-27 M. Figueira , C. López-Calderón , L. Bronfman , A. Zavagno , C. Hervías-Caimapo , N. Duronea , L-Å. Nyman

Context. Class II methanol masers at 6.7 and 12.2 GHz occur close to high-mass young stellar objects (HMYSOs). When they are observed simultaneously, such studies may contribute to refining the characterisation of local physical conditions.…

Astrophysics of Galaxies · Physics 2021-04-28 M. Durjasz , M. Szymczak , P. Wolak , A. Bartkiewicz

We derive the molecular properties for a sample of 301 Galactic HII regions including 123 ultra compact (UC), 105 compact, and 73 diffuse nebulae. We analyze all sources within the BU-FCRAO Galactic Ring Survey (GRS) of 13CO emission known…

Using data from the all-sky Wide-Field Infrared Survey Explorer (WISE) satellite, we made a catalog of over 8000 Galactic HII regions and HII region candidates by searching for their characteristic mid-infrared (MIR) morphology. WISE has…

Astrophysics of Galaxies · Physics 2015-06-18 L. D. Anderson , T. M. Bania , Dana S. Balser , V. Cunningham , T. V. Wenger , B. M. Johnstone , W. P. Armentrout

HII regions are the ionized spheres surrounding high-mass stars. They are ideal targets for tracing Galactic structure because they are predominantly found in spiral arms and have high luminosities at infrared and radio wavelengths. In the…

Astrophysics of Galaxies · Physics 2015-09-09 L. D. Anderson , L. A. Hough , T. V. Wenger , T. M. Bania , Dana S. Balser

Using the Owens Valley and Nobeyama Radio Observatory interferometers, we carried out an unbiased search for hot molecular cores and ultracompact UC HII regions toward the high-mass star forming region G19.61--0.23. In addition, we…

Astrophysics · Physics 2009-11-10 R. S. Furuya , R. Cesaroni , S. Takahashi , M. Momose , L. Testi , H. Shinnaga , C. Codella

Ultra compact HII (UCHII) regions are indicators of high-mass star formation sites and are distributed mainly in the Galactic plane. We intend to investigate the possible contribution of the forthcoming ESA Planck mission to the science of…

Solar and Stellar Astrophysics · Physics 2015-05-14 P. Leto , G. Umana , C. Trigilio , C. S. Buemi , S. Dolei , P. Manzitto , L. Cerrigone , C. Siringo

We have used the Australia Telescope Compact Array (ATCA) to make observations of a sample of eight young ultra-compact HII regions, selected on the basis that they have associated class II methanol maser emission. We have made observations…

Astrophysics · Physics 2009-11-10 S. P. Ellingsen , S. S. Shabala , S. E. Kurtz

We present observations of the H91$\alpha$ recombination line emission towards a sample of nine HII regions associated with 6.7-GHz methanol masers, and report arcsecond-scale emission around compact cores. We derive physical parameters for…

Astrophysics · Physics 2009-11-11 Stanislav Shabala , Simon Ellingsen , Stan Kurtz , Larry Forbes

We present the results of a survey of a small sample (14) of low-mass protostars (L_IR < 10^3 Lsun) for 6.7 GHz methanol maser emission performed using the ATNF Parkes radio telescope. No new masers were discovered. We find that the lower…

Astrophysics · Physics 2009-11-11 Tyler L. Bourke , A. R. Hyland , Garry Robinson

We present deep 3.6 cm radio continuum observations of the HII region W40 obtained using the Very Large Array in its A and B configurations. We detect a total of 20 compact radio sources in a region of 4 x 4 arcmin, with 11 of them…

Astrophysics of Galaxies · Physics 2015-05-19 Luis F. Rodríguez , Steven A. Rodney , Bo Reipurth

The formation of hypercompact (HC) HII regions is an important stage in massive star formation. Spectral line and continuum observations can explore its dynamic conditions. We present high angular resolution observations carried out with…

Astrophysics of Galaxies · Physics 2014-09-29 Chuan-Peng Zhang , Jun-Jie Wang , Jin-Long Xu , Friedrich Wyrowski , Karl M. Menten

The Australia Telescope Compact Array (ATCA) has been used to make the first extensive search for the class I methanol masers at 9.9 GHz. In total, 48 regions of high-mass star formation were observed. In addition to masers in W33-Met…

Astrophysics of Galaxies · Physics 2015-05-18 M. A. Voronkov , J. L. Caswell , S. P. Ellingsen , A. M. Sobolev

A sensitive broadband molecular line survey of the Sagittarius B2(N) star-forming region has been obtained with the HIFI instrument on the Herschel Space Observatory, offering the first high-spectral resolution look at this well-studied…

A survey of young bipolar outflows in regions of low-to-intermediate-mass star formation has been carried out in two class I methanol maser transitions: 7_0-6_1A+ at 44 GHz and 4_{-1}-3_0E at 36 GHz. We detected narrow features towards NGC…

Astrophysics of Galaxies · Physics 2015-05-18 S. V. Kalenskii , L. E. B. Johansson , P. Bergman , S. Kurtz , P. Hofner , C. M. Walmsley , V. I. Slysh

Using the Very Large Array (VLA) at 3.6~cm we identify four new compact radio sources in the vicinity of the cometary HII region G78.4+2.6 (VLA~1). The four compact radio sources (named VLA~2 to VLA~5), have near-infrared counterparts, as…

Astrophysics of Galaxies · Physics 2010-06-22 Citlali Neria , Yolanda Gomez , Luis F. Rodriguez

We present a complete sample of molecular clumps containing compact and ultra-compact (UC) HII regions between \ell=10\degr and 60\degr\ and $|b|<1\degr, identified by combining the the ATLASGAL submm and CORNISH radio continuum surveys…

The Purple Mountain Observatory 13.7 m radio telescope has been used to search for 95 GHz (8$_0$--7$_1$A$^+$) class I methanol masers towards 1020 Bolocam Galactic Plane Survey (BGPS) sources, leading to 213 detections. We have compared the…

Astrophysics of Galaxies · Physics 2017-08-23 Wenjin Yang , Ye Xu , Xi Chen , Simon P. Ellingsen , Dengrong Lu , Binggang Ju , Yingjie Li