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We have used the Australia Telescope Compact Array (ATCA) to make new observations of the 36.2-GHz ($4_{-1}\rightarrow3_0$E) methanol transition toward NGC 4945 and NGC 253. These observations have revealed the presence of new maser…

Astrophysics of Galaxies · Physics 2021-10-20 Tiege McCarthy , Simon Ellingsen , Shari Breen , Maxim Voronkov , Xi Chen , Hai-Hua Qiao

We present ground-based 2.1 to 4.2 microns observations of four low-mass protostars. We searched for the 4.1 microns OD stretch band, characteristic of solid HDO in grain mantles. We did not detect solid HDO in any of the four sources, but…

Astrophysics · Physics 2009-11-10 B. Parise , T. Simon , E. Caux , E. Dartois , C. Ceccarelli , J. Rayner , A. G. G. M. Tielens

The aim of this study is to investigate the distribution and excitation of the methanol gas around Cep A and to describe the physical conditions of the region. In addition the large scale abundance distribution is determined in order to…

We report results of 6.7 GHz methanol maser monitoring of 139 star-forming sites with the Torun 32 m radio telescope from June 2009 to February 2013. The targets were observed at least once a month, with higher cadences of 2-4 measurements…

Astrophysics of Galaxies · Physics 2017-12-20 Marian Szymczak , Mateusz Olech , Rafał Sarniak , Paweł Wolak , Anna Bartkiewicz

We present sub-arcsecond observations toward the massive star forming region G75.78+0.34. We used the Very Large Array to study the centimeter continuum and H2O and CH3OH maser emission, and the Owens Valley Radio Observatory and…

Astrophysics of Galaxies · Physics 2015-06-15 Alvaro Sanchez-Monge , Stan Kurtz , Aina Palau , Robert Estalella , Debra Shepherd , Susana Lizano , Jose Franco , Guido Garay

Context: High-mass young stellar objects (HMYSOs) can undergo accretion episodes that strongly affect the star evolution, the dynamics of the disk, and its chemical evolution. Recently reported extraordinary bursts in the methanol maser…

Astrophysics of Galaxies · Physics 2018-09-19 Marian Szymczak , Mateusz Olech , Paweł Wolak , Eric Gérard , Anna Bartkiewicz

We have used the Karl G. Jansky Very Large Array (VLA) to search for 36 GHz and 44 GHz methanol (CH3OH) lines in a sample of 21 Galactic supernova remnants (SNRs). Mainly the regions of the SNRs with 1720 MHz OH masers were observed.…

Astrophysics of Galaxies · Physics 2015-06-18 Y. M. Pihlström , L. O. Sjouwerman , D. A. Frail , M. J. Claussen , R. A. Mesler , B. C. McEwen

We present the results of an interferometric study of 38 millimeter-wave lines of CH3OH in the region around the water maser source W3(H2O) and a region extending about 30" to the south and west of the hydroxyl maser source W3(OH). The…

We have detected emission from both the 4_{-1}-3_{0} E (36.2~GHz) class I and 7_{-2}-8_{-1} E (37.7~GHz) class II methanol transitions towards the centre of the closest ultra-luminous infrared galaxy Arp 220. The emission in both the…

Astrophysics of Galaxies · Physics 2015-06-23 Xi Chen , Simon P. Ellingsen , Willem A. Baan , Hai-Hua Qiao , Juan Li , Tao An , Shari L. Breen

A sensitive search for 6.7--GHz methanol maser emission has been made towards 10 galaxies that have yielded detectable microwave molecular--line transitions. These include several which show OH megamaser or superluminous \water\/ maser…

Astrophysics · Physics 2015-06-24 S. P. Ellingsen , R. P. Norris , J. B. Whiteoak , R. A. Vaile , P. M. McCulloch , M. Price

We used the IRAM Interferometer to obtain sub-arcsecond resolution observations of the high-mass star-forming region W3(OH) and its surroundings at a frequency of 220 GHz. With the improved angular resolution, we distinguish 3 peaks in the…

Astrophysics · Physics 2009-10-31 Friedrich Wyrowski , Peter Schilke , C. Malcolm Walmsley , Karl M. Menten

We report the discovery of a widespread population of collisionally excited methanol J = 4_{-1} to 3$_0 E sources at 36.2 GHz from the inner 66'x18' (160x43 pc) of the Galactic center. This spectral feature was imaged with a spectral…

Astrophysics of Galaxies · Physics 2015-06-12 F. Yusef-Zadeh , W. Cotton , S. Viti , M. Wardle , M. Royster

A previously unseen maser in the J = 1 - 0 transition of HCO$^+$ has been detected by the Combined Array for Millimeter-wave Astronomy (CARMA). A sub-arcsecond map was produced of the 2 arcmin$^2$ region around DR21(OH), which has had…

Astrophysics of Galaxies · Physics 2012-09-25 Nicholas S. Hakobian , Richard M. Crutcher

We have used the Australia Telescope Compact Array (ATCA) to search for emission from the $4_{-1} \rightarrow 3_{0}E$ transition of methanol (36.2 GHz) towards the center of the nearby starburst galaxy NGC253. Two regions of emission were…

Astrophysics of Galaxies · Physics 2015-06-22 Simon Ellingsen , Xi Chen , Hai-Hua Qiao , Willem Baan , Tao An , Juan Li , Shari Breen

The Australia Telescope Compact Array (ATCA) has been used for high angular resolution imaging of 71 southern class I methanol maser sources quasi-simultaneously at 36 and 44 GHz. The data reveal a high level of morphological and…

Astrophysics of Galaxies · Physics 2015-06-18 M. A. Voronkov , J. L. Caswell , S. P. Ellingsen , J. A. Green , S. L. Breen

Observational signatures of infalling envelopes and outflowing material in early stages of protostellar evolution, and at small radii from the protostar, are essential to progress in the understanding of the mass-accretion process in star…

Astrophysics of Galaxies · Physics 2015-05-30 C. Goddi , L. Moscadelli , A. Sanna

The Australia Telescope National Facility Mopra millimetre telescope has been used to search for 95.1-GHz class I methanol masers towards sixty-two 6.6-GHz class II methanol masers. A total of twenty-six 95.1-GHz masers were detected,…

Astrophysics · Physics 2009-11-10 S. P. Ellingsen

We present observations of the (1,1), (2,2), (4,4) and (5,5) inversion transitions of para-ammonia (NH3) and 24 GHz continuum, taken with the Australia Telescope Compact Array toward 21 southern Galactic hot molecular cores traced by 6.7…

Astrophysics · Physics 2008-12-18 S. N. Longmore , M. G. Burton , P. J. Barnes , T. Wong , C. R. Purcell , J. Ott

Methanol masers which are traditionally divided into two classes provide possibility to study important parts of the star forming regions: Class~II masers trace vicinities of the massive YSOs while class~I masers are likely to trace more…

We describe a systematic program aimed at identifying and characterizing candidate high-mass proto-stellar objects (HMPOs). Our candidate sample consists of 69 objects selected by criteria based on those established by Ramesh & Sridharan…

Astrophysics · Physics 2009-11-07 T. K. Sridharan , H. Beuther , P. Schilke , K. M. Menten , F. Wyrowski