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From a survey for redshifted HI 21-cm and OH 18-cm absorption in the hosts of a sample of radio galaxies and quasars, we detect HI in three of the ten and OH in none of the fourteen sources for which useful data were obtained. As expected…

Cosmology and Nongalactic Astrophysics · Physics 2015-05-20 S. J. Curran , M. T. Whiting , M. T. Murphy , J. K. Webb , C. Bignell , A. G. Polatidis , T. Wiklind , P. Francis , G. Langston

The 25 years following the serendipitous discovery of megamasers have seen tremendous progress in the study of luminous extragalactic H$_2$O emission. Single-dish monitoring and high resolution interferometry have been used to identify…

Astrophysics · Physics 2009-11-10 C. Henkel , J. A. Braatz , A. Tarchi , A. B. Peck , N. M. Nagar , L. J. Greenhill , M. Wang , Y. Hagiwara

We present a comparison of Spitzer IRS data for 51 OH megamaser (OHM) hosts and 15 non-masing ULIRGs. 10-25% of OHMs show evidence for the presence of an AGN, significantly lower than the estimated AGN fraction from previous optical and…

Cosmology and Nongalactic Astrophysics · Physics 2015-05-27 Kyle W. Willett , Jeremy Darling , Henrik W. W. Spoon , Vassilis Charmandaris , Lee Armus

Herbig-Haro objects are regions of shocked gas and dust which are produced when collimated outflows from a protostar interact with the surrounding dense gas. They have many similarities to supernova remnants which are interacting with…

Astrophysics of Galaxies · Physics 2015-06-18 A. de Witt , M. Bietenholz , R. Booth , M. Gaylard

We report on the first space-VLBI observations of the OH masers in two main-line OH transitions at 1665 and 1667 MHz. The observations involved the space radio telescope on board the Japanese satellite HALCA and an array of ground radio…

Astrophysics · Physics 2007-05-23 V. I. Slysh , M. A. Voronkov , I. E. Val'tts , V. Migenes , K. M. Shibata , T. Umemoto

Using archival data from the HI Parkes All Sky Survey (HIPASS) we have searched for 21 cm line absorption in 204 nearby radio and star-forming galaxies with continuum flux densities greater than $S_{1.4} \approx 250$ mJy within the redshift…

Astrophysics of Galaxies · Physics 2015-06-18 J. R. Allison , E. M. Sadler , A. M. Meekin

Using the Five-hundred-meter Aperture Spherical radio Telescope (FAST), we have performed an Ursa Major supergroup HI Survey (FUMaS) covering the entire UMa region centered at RA=11$^h$59$^m$28$^s$.3, DEC=49$^\circ$05'18" with a radius of…

Astrophysics of Galaxies · Physics 2025-05-21 Haiyang Yu , Ming Zhu , Chuan-Peng Zhang , Peng Jiang , Jin-Long Xu

This study uses archival high frequency continuum data to expand the search for Hypercompact HII regions and determine the conditions at which they appear, as this stage high mass star formation is short-lived and rare. We use 23 GHz…

We present results of a high resolution survey of OH masers in Galactic Star Forming Regions in order to study the maser emission and establish a list of suitable candidates for higher resolution instruments follow up. We used the Very Long…

Astrophysics · Physics 2007-05-23 A. E. Ruiz-Velasco , V. Migenes , V. Slysh , I. E. Val'tts

We present Gemini Multi-Object Spectrograph (GMOS) Integral Field Unit (IFU), Hubble Space Telescope (HST) and Very Large Array (VLA) observations of the OH Megamaser (OHM) galaxy IRAS 11506-3851. The HST images reveal an isolated spiral…

We report the detection of OH satellite line masers at 1720 MHz and 1612 MHz from the nuclear region of the starburst galaxy M82. The observations were aimed at detecting 1720 MHz maser emission from the known radio emitting SNR in the…

Astrophysics · Physics 2015-06-24 E. R. Seaquist , D. T. Frayer , D. A. Frail

We present observations of molecular gas made with the 15-m James Clark Maxwell Telescope toward the sites of OH(1720 MHz) masers in three supernova remnants: W28, W44 and 3C391. Maps made in the 12CO J=3-2 line reveal that the OH masers…

Astrophysics · Physics 2009-10-30 Dale A. Frail , George F. Mitchell

Context. A key property of massive stars is their high degree of multiplicity, which can impact their evolution and end-of-life products. The Southern Massive Stars at High Angular Resolution survey (smash+) use interferometric and…

Solar and Stellar Astrophysics · Physics 2025-09-24 F. Tramper , H. Sana , A. de Koter , T. Pauwels

The excited states of OH masers detected in the environment of high-mass young stellar objects (HMYSOs) are important for improving our understanding of the physical conditions of these objects and also provide information about their…

Astrophysics of Galaxies · Physics 2020-10-14 M. Szymczak , P. Wolak , A. Bartkiewicz , M. Aramowicz , M. Durjasz

Class I methanol masers are collisionally pumped and are generally correlated with outflows in star forming sites in the Galaxy. Using the VLA in its A-array configuration, we present a spectral line survey to identify methanol…

Astrophysics of Galaxies · Physics 2016-12-14 W. Cotton , F. Yusef-Zadeh

The massive star-forming region G11.904-0.141 is one of only 11 sources to show maser emission in the highly-excited 13441 MHz transition of OH. VLBA observations of the 1665, 1667, 4765, and 13441 MHz transitions of OH toward G11.904-0.141…

Astrophysics · Physics 2009-11-13 Vincent L. Fish

We have undertaken a comprehensive search for 5-cm excited OH maser emission from evolved stars representative of various stages of late stellar evolution. Observed sources were selected from known 18-cm OH sources. This survey was…

Astrophysics · Physics 2009-11-07 J. -F. Desmurs , A. Baudry , P. Sivagnanam , C. Henkel

Maser lines from different molecular species, including water, hydroxyl, and methanol, are common observational phenomena associated with massive star forming regions. In particular, the methanol maser appears as an ideal tool to study the…

Astrophysics of Galaxies · Physics 2014-06-04 L. Olmi , E. D. Araya , P. Hofner , S. Molinari , J. Morales Ortiz , L. Moscadelli , M. Pestalozzi

We present high spatial resolution observations of ground-state OH masers achieved with the Australia Telescope Compact Array (ATCA). These observations targeted 253 pointing centres containing OH maser candidates at all four ground-state…

The OH Megamaser emission in the merging galaxy Arp220 has been re-observed with the Multi-Element Radio Linked Interferometer Network (MERLIN) and the European VLBI Network (EVN). Imaging results of the OH line emission at the two nuclei…

Astrophysics of Galaxies · Physics 2023-06-28 W. A. Baan , J. N. H. S. Aditya , T. An , H-R. Klöckner