Strong magnetic field in W75N OH maser flare

A flare of OH maser emission was discovered in W75N in 2000. Its location was determined with the VLBA to be within 110 au from one of the ultracompact H II regions, VLA2. The flare consisted of several maser spots. Four of the spots were found to form Zeeman pairs, all of them with a magnetic field strength of about 40 mG. This is the highest ever magnetic field strength found in OH masers, an order of magnitude higher than in typical OH masers. Three possible sources for the enhanced magnetic field are discussed: (i) the magnetic field of the exciting star dragged out by the stellar wind; (ii) the general interstellar field in the gas compressed by the MHD shock; and (iii) the magnetic field of planets which orbit the exciting star and produce maser emission in gaseous envelopes.Comment: 5 pages, 3 figures. to be published in MNRA

A Search for Water Masers Toward YSO Candidates in the LMC

The proximity of the Large Magellanic Cloud (LMC) and its high star formation rate make it a prime candidate for the study of massive star formation outside of the Milky Way. A search for water masers associated with massive young stellar objects (YSOs) was conducted toward 25 star-forming regions in the LMC. A total of 11 masers toward two regions were detected. Two continuum sources were detected and one was matched with a YSO candidate based off of Spitzer infrared data. Detection of associated masers strengthen their candidacy as high-mass YSOs, significantly increase the number of known extra-galactic masers, and give insight into massive star formation outside of our galaxy

High-Resolution H2O Maser Observations toward IRAS Sources in Bright-Rimmed Clouds

Bright-rimmed clouds (BRCs) are clouds that have been compressed by an external ionization shock front. We present the first high-resolution VLA observations of 20 of these BRCs in the northern hemisphere. We detected water maser emission from three objects: IRAS 21346+5714 (BRC 36), IRAS 21388+5622 (BRC 37), and IRAS 21445+5712 (BRC 39). The low detection rate supports the evidence that BRCs produce mostly low-luminosity objects, for which maser emission is weak and episodic, and suggests that the embedded sources are in a more advanced evolutionary phase than Class 0 objects

Low-mass star formation in bright rimmed clouds

AbstractBright Rimmed Clouds (BRCs) are clouds that have been compressed by an external ionization-shock front which focuses the neutral gas into compact globules. The boundary layer between the neutral gas and the gas ionized by the incident photons is often called "bright rim" but the clumps are sometimes classified also as speck globules or cometary globules depending on their appearance. Small globules with bright rims have been considered to be potential sites of star formation and have been studied in several individual regions. We present the first high resolution VLA observations of 20 of these BRCs, but only three detections were obtained. The low detection rate seems to support the idea that BRCs produce mostly low-luminosity objects, for which maser emission is weak and episodic, and that the embedded sources are in a more advanced evolutionary phase than class 0 objects