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Methanol masers at 6.7 GHz have been found exclusively towards high-mass star forming regions. Recently, some Class 0 protostars have been found to display conditions similar to what are found in hot cores that are associated with massive…

Astrophysics · Physics 2009-11-13 J. D. Pandian , S. Leurini , K. M. Menten , A. Belloche , P. F. Goldsmith

We conducted a HI 21cm absorption study of a sample of 147 nearby (z < 0.1) low-power radio sources with $10\,\mathrm{mJy} < S_{1.4\,\mathrm{GHz}} < 30\,\mathrm{mJy}$ and $\log(P_{1.4\,\mathrm{GHz}}/\mathrm{W\,Hz^{-1}}) = 20.5-23.7$, using…

Astrophysics of Galaxies · Physics 2026-03-06 Yang Su , Qingzheng Yu , Taotao Fang , Junfeng Wang , Jianfeng Wu , Bo Zhang

Methanol masers at 6.7 GHz are well known tracers of high-mass star-forming regions. However, their origin is still not clearly understood. We aimed to determine the morphology and velocity structure for a large sample of the maser emission…

Astrophysics of Galaxies · Physics 2016-03-02 Anna Bartkiewicz , Marian Szymczak , Huib J. van Langevelde

The classic HII region M17 is one of the best studied across the electromagnetic spectrum. We present sensitive, high angular resolution observations made with the Jansky Very Large Array (JVLA) at 4.96 and 8.46 GHz that reveal the presence…

Solar and Stellar Astrophysics · Physics 2015-06-05 Luis F. Rodriguez , Ricardo F. Gonzalez , Gabriela Montes , Hassan M. Asiri , Alejandro C. Raga , Jorge Canto

We use SCUBA 850 micron and CO observations to analyze the surroundings of three Galactic ring-like HII regions, KR 7, KR 81, and KR 120 (Sh 2-124, Sh 2-165 and Sh 2-187), with the aim of finding sites of triggered star formation. We find…

Astrophysics of Galaxies · Physics 2015-05-27 Kim Arvidsson , Charles R. Kerton

We aim to investigate the chemistry of internal photon-dominated regions surrounding deeply embedded hypercompact and ultracompact HII regions. We search for specific tracers of this evolutionary stage of massive star formation that can be…

We characterize the molecular environment of candidate massive young stellar objects (MYSOs) signposted by methanol masers. Single pixel observations of 10 transitions of HCO^+, CO and CS isotopomers were carried out, using the IRAM 30m…

Astrophysics · Physics 2009-11-13 M. Szymczak , A. Bartkiewicz , A. M. S. Richards

I present here the summary of results from a survey by De Buizer (2003) searching for outflows using near-infrared imaging. Targets were massive young stellar objects associated with methanol masers in linear distributions. Presently, it is…

Astrophysics · Physics 2007-05-23 James M. De Buizer

We present molecular line observations made with the IRAM 30-m telescope of the immediate surroundings of a sample of 11 candidate high-mass protostars. These observations are part of an effort to clarify the evolutionary status of a set of…

Astrophysics · Physics 2009-11-06 J. Brand , R. Cesaroni , F. Palla , S. Molinari

We have examined methanol emission from Orion KL with of the {\em Herschel}/HIFI instrument, and detected two methanol bands centered at 524 GHz and 1061 GHz. The 524 GHz methanol band (observed in HIFI band 1a) is dominated by the isolated…

Abridged. Methods. We made use of the Karl G. Jansky Very Large Array (VLA) in the B configuration at K band, and in the A configuration at both Ku and C bands, in order to image the radio continuum emission towards 25 H$_2$O maser sites…

Solar and Stellar Astrophysics · Physics 2018-11-14 A. Sanna , L. Moscadelli , C. Goddi , V. Krishnan , F. Massi

We present the results of studies of a new class of 6.7 GHz methanol maser sources with a ring-like emission structure discovered recently with the EVN. We have used the VLA to search for water masers at 22 GHz and radio continuum at 8.4…

Astrophysics of Galaxies · Physics 2015-03-18 A. Bartkiewicz , M. Szymczak , H. J. van Langevelde , J. M. De Buizer , Y. Pihlström

Massive star-forming regions exhibit a rich chemistry with complex gas distributions, especially on small scales. While surveys have yielded constraints on typical gas conditions, they often have coarse spatial resolution and limited…

In the early days of methanol maser discoveries the 9(2)-10(1) A+ transition at 23.1 GHz was found to exhibit maser characteristics in the northern star-forming region W3(OH), and probable maser emission in two other sources. Attention…

Astrophysics · Physics 2009-11-10 D. M. Cragg , A. M. Sobolev , J. L. Caswell , S. P. Ellingsen , P. D. Godfrey

We present Very Large Array 7 mm continuum observations of four Ultra-Compact (UC)HII regions, observed previously at 1.3 cm, in order to investigate the nature of the compact radio sources associated with these regions. We detected a total…

We report simultaneous single-dish surveys of 22 GHz H2O and 44 and 95 GHz class I CH3OH masers toward 299 Red MSX Sources in the protostellar stage. The detection rates are 45% at 22 GHz, 28% at 44 GHz, and 23% at 95 GHz. There are 15, 53,…

Astrophysics of Galaxies · Physics 2018-05-23 Chang-Hee Kim , Kee-Tae Kim , Yong-Sun Park

Aims: We searched for the molecular outflows from fifteen molecular clouds associated with ultra-compact and compact HII (UCHII/HII) regions and discussed possible gas heating mechanism. Methods: Mapping observations of CO $J=3-2$ and…

Astrophysics · Physics 2009-11-13 Sheng-Li Qin , Jun-Jie Wang , Gang Zhao , Martin Miller , Jun-Hui Zhao

Context: NGC7538 is known to host a 6.7 and 12.2GHz methanol maser cospatial with a Ultra Compact (UC) HII region, IRS1. Aims: We report on the serendipitous discovery of two additional 6.7GHz methanol masers in the same region, not…

Astrophysics · Physics 2007-05-23 M. Pestalozzi , V. Minier , F. Motte , J. Conway

As part of the GLOSTAR survey we have used the VLA in its B-configuration to observe the part of the Galactic plane between longitudes of 28d and 36d and latitudes from -1d to +1d at the C-band (4--8 GHz). To reduce the contamination of…

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