High-Sensitivity Observations of Molecular Lines with the Arecibo Telescope
Autor: | W. S. Tan, Esteban Araya, L E Lee, Stan Kurtz, Luca Olmi, Peter Hofner, H. Linz |
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Jazyk: | angličtina |
Rok vydání: | 2020 |
Předmět: |
Physics
Mass star 010308 nuclear & particles physics FOS: Physical sciences Astronomy and Astrophysics Astrophysics Rms noise Astrophysics - Astrophysics of Galaxies 01 natural sciences law.invention Telescope Space and Planetary Science law Astrophysics of Galaxies (astro-ph.GA) Excited state 0103 physical sciences Outflow Maser 010303 astronomy & astrophysics |
Popis: | We report on one of the highest sensitivity surveys for molecular lines in the frequency range 6.0 to 7.4 GHz conducted to date. The observations were done with the 305m Arecibo Telescope toward a sample of twelve intermediate/high-mass star forming regions. We searched for a large number of transitions of different molecules, including CH3OH and OH. The low RMS noise of our data (~5 mJy for most sources and transitions) allowed detection of spectral features that have not been seen in previous lower sensitivity observations of the sources, such as detection of excited OH and 6.7 GHz CH3OH absorption. A review of 6.7 GHz CH3OH detections indicates an association between absorption and radio continuum sources in high-mass star forming regions, although selection biases in targeted projects and low sensitivity of blind surveys imply incompleteness. Absorption of excited OH transitions was also detected toward three sources. In particular, we confirm a broad 6.035 GHz OH absorption feature in G34.26+0.15 characterized by an asymmetric blue-shifted wing indicative of expansion, perhaps a large scale outflow in this HII region. 19 pages, 8 figures. Accepted for publication in MNRAS |
Databáze: | OpenAIRE |
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