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Molecular maser lines are signposts of high-mass star formation, probing excitation and kinematics of very compact regions in the close environment of young stellar objects and providing useful targets for trigonometric parallax…

Astrophysics of Galaxies · Physics 2022-04-12 Y. T. Yan , C. Henkel , K. M. Menten , Y. Gong , J. Ott , T. L. Wilson , A. Wootten , A. Brunthaler , J. S. Zhang , J. L. Chen , K. Yang

Using the Karl G. Jansky Very Large Array (VLA), we have conducted a survey for 22 GHz, 6_{1,6}-5_{2,3} H2O masers toward the Serpens South region. The masers were also observed with the Very Long Baseline Array (VLBA) following the VLA…

Results of a survey of Galactic star-forming regions in the lines of methanol 8_{-1}-7_0E at 229.8 GHz, 3_{-2}-4_{-1}E at 230.0 GHz, 0_0-1_{-1}E at 108.9 GHz, and a series of methanol lines J_1-J_0E near 165 GHz are presented. Two masers,…

Astrophysics · Physics 2007-05-23 S. V. Kalenskii , V. I. Slysh , I. E. Val'tts

We present the first detection of a 6.7 GHz Class II methanol (CH3OH) maser in the Andromeda galaxy (M31). The CH3OH maser was found in a Very Large Array (VLA) survey during the fall of 2009. We have confirmed the methanol maser with the…

Astrophysics of Galaxies · Physics 2015-05-20 Lorant O. Sjouwerman , Claire E. Murray , Ylva M. Pihlstrom , Vincent L. Fish , Esteban D. Araya

We present the results of a search for ammonia maser emission in 119 Galactic high-mass star-forming regions (HMSFRs) known to host 22 GHz H$_2$O maser emission. Our survey has led to the discovery of non-metastable NH$_3$ inversion line…

Astrophysics of Galaxies · Physics 2024-06-19 Y. T. Yan , C. Henkel , K. M. Menten , T. L. Wilson , A. Wootten , Y. Gong , F. Wyrowski , W. Yang , A. Brunthaler , A. Kraus , B. Winkel

An overview is given of the analysis of more than a decade of H2O maser data from our monitoring program. We find the maser emission to generally depend on the luminosity of the YSO as well as on the geometry of the SFR. There appears to be…

Astrophysics · Physics 2009-11-10 J. Brand , R. Cesaroni , G. Comoretto , M. Felli , F. Palagi , F. Palla , R. Valdettaro

Various theoretical models predict the existence of extended $\gamma$-ray halo around normal galaxies that could be produced by interactions of cosmic rays with the circumgalactic medium or by annihilation or decay of hypothetical dark…

High Energy Astrophysical Phenomena · Physics 2026-04-03 M. S. Pshirkov , B. A. Nizamov

We present high angular resolution (FWHM_beam < 0.2") observations of the 23.1-GHz methanol (CH_3OH) transition toward the massive-star forming region NGC 7538 IRS 1. The two velocity components previously reported by Wilson et al. are…

Astrophysics of Galaxies · Physics 2015-05-18 Roberto Galván-Madrid , Gabriela Montes , Edgar A. Ramírez , Stan Kurtz , Esteban Araya , Peter Hofner

We conducted VLA C-configuration observations to measure positions and luminosities of Galactic Class II 6.7 GHz methanol masers and their associated ultra-compact H II regions. The spectral resolution was 3.90625 kHz and the continuum…

Astrophysics of Galaxies · Physics 2016-12-14 Bo Hu , Karl M. Menten , Yuanwei Wu , Anna Bartkiewicz , Kazi Rygl , Mark J. Reid , James S. Urquhart , Xingwu Zheng

We present maps of the 6 cm and 1.3 mm transitions of formaldehyde toward three cold, dense pre-protostellar cores: L1498, L1512, and L1544. The 6 cm transition is a unique probe of high density gas at low temperature. However, our models…

Astrophysics · Physics 2009-11-10 Kaisa E. Young , Jeong-Eun Lee , Neal J. Evans , Paul F. Goldsmith , Steven D. Doty

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

Recently, a comparison between the locations of 6.7-GHz methanol masers and dust continuum emission has renewed speculation that these masers can be associated with evolved stars. The implication of such a scenario would be profound,…

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 a study of molecular outflows using high-resolution mapping of the CO (1-0) line emission toward eight relatively nearby 6.7 GHz methanol masers, which are associated with massive star forming regions. Outflows were detected in…

Astrophysics · Physics 2008-11-26 Y. Xu , Z. -Q. Shen , J. Yang , X. W. Zheng , A. Miyazaki , K. Sunada , H. J. Ma , J. J. Li , J. X. Sun , C. C. Pei

We performed a systematic 6.7 GHz Class \uppercase\expandafter{\romannumeral2} methanol maser survey using the Shanghai Tianma Radio Telescope toward targets selected from the all-sky \emph{Wide-Field Infrared Survey Explorer (WISE)} point…

Astrophysics of Galaxies · Physics 2019-04-30 Kai Yang , Xi Chen , Zhi-Qiang Shen , Xiao-Qiong Li , Jun-Zhi Wang , Dong-Rong Jiang , Juan Li , Jian Dong , Ya-Jun Wu , Hai-Hua Qiao , Zhiyuan Ren

The RadioAstron space-VLBI mission has successfully detected extragalactic H2O MegaMaser emission regions at very long Earth to space baselines ranging between 1.4 and 26.7 Earth Diameters (ED). The preliminary results for two galaxies,…

The present paper focuses on the high-mass star-forming region G16.59-0.05. Methods: Using the VLBA and the EVN arrays, we conducted phase-referenced observations of the three most powerful maser species in G16.59-0.05: H2O at 22.2 GHz (4…

Astrophysics of Galaxies · Physics 2015-05-18 A. Sanna , L. Moscadelli , R. Cesaroni , A. Tarchi , R. S. Furuya , C. Goddi

Methanol and water vapour masers are signposts of early stages of high-mass star formation but it is generally thought that due to different excitation processes they probe distinct parts of stellar environments. Here we present…

Solar and Stellar Astrophysics · Physics 2016-04-05 M. Szymczak , M. Olech , P. Wolak , A. Bartkiewicz , M. Gawronski

Aims. We report the discovery of periodic maser variability of an unusual pattern in the high-mass young stellar object G26.598-0.024. Methods. A ten-year monitoring of the 6.7 GHz methanol maser was carried out with the Torun 32 m radio…

Astrophysics of Galaxies · Physics 2025-08-14 P. Wolak , M. Szymczak , A. Kobak , A. Varma , A. Bartkiewicz , J. O. Chibueze , B. Stecklum , C. J. Ugwu

The Central Molecular Zone (CMZ) spans the inner ~450 pc (3 degrees) of our Galaxy. This region is defined by its enhanced molecular emission and contains 5% of the entire Galaxy's molecular gas mass. However, the number of detected star…

Astrophysics of Galaxies · Physics 2019-01-16 Matthew Rickert , F. Yusef-Zadeh , J. Ott
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