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Aims: The main goal of this study is to perform a sub-arcsecond resolution analysis of the high-mass star formation region G19.61-0.23, both in the continuum and molecular line emission. While the centimeter continuum images will be…

太阳与恒星天体物理 · 物理学 2015-05-19 R. S. Furuya , R. Cesaroni , H. Shinnaga

A ring of dense molecular gas extending 2-7 pc orbits the supermassive black hole Sgr A* at the center of our Galaxy. Using the Green Bank Telescope, we detected water maser lines and both narrow (0.35 km/s) and broad (30 - 50 km/s)…

天体物理学 · 物理学 2009-11-13 F. Yusef-Zadeh , J. Braatz , M. Wardle , D. Roberts

Molecular lines tracing the orbital motion of gas in a well-defined disk are valuable tools for inferring both the properties of the disk and the star it surrounds. Lines that arise only from a disk, and not also from the surrounding…

We present wide area radio (12 mm) Mopra Telescope observations of the complex and rich massive star forming region G305. Our goals are to determine the reservoir for star formation within G305 using NH3 to trace the dense molecular…

星系天体物理 · 物理学 2015-05-19 L. Hindson , M. A. Thompson , J. S. Urquhart , J. S. Clark , B. Davies

The circumstellar ammonia (NH$_3$) chemistry in evolved stars is poorly understood. Previous observations and modelling showed that NH$_3$ abundance in oxygen-rich stars is several orders of magnitude above that predicted by equilibrium…

太阳与恒星天体物理 · 物理学 2018-04-25 K. T. Wong , K. M. Menten , T. Kamiński , F. Wyrowski , J. H. Lacy , T. K. Greathouse

We have observed the massive star forming region associated with the early B protostar G192.16-3.84 in NH3(1,1), 22.2 GHz water masers, 1.3 cm continuum emission, and at 850 microns. The dense gas associated with G192.16 is clumpy,…

天体物理学 · 物理学 2009-11-10 D. S. Shepherd , T. Borders , M. Claussen , Y. Shirley , S. E. Kurtz

We present the results of the observations of the (J,K)=(1,1) and the (J,K)=(2,2) inversion transitions of the NH3 molecule toward a large sample of 40 regions with molecular or optical outflows, using the 37 m radio telescope of the…

太阳与恒星天体物理 · 物理学 2015-05-27 I. Sepúlveda , G. Anglada , R. Estalella , R. López , J. M. Girart , J. Yang

We report on a water maser survey towards a sample of 27 planetary nebulae (PNe) using the Robledo de Chavela and Medicina single-dish antennas, as well as the Very Large Array (VLA). Two detections have been obtained: the already known…

We present results of continuum and spectral line observations with ALMA and 22 GHz water (H$_2$O) maser observations using KaVA and VERA toward a high-mass star-forming region, G25.82-0.17. Multiple 1.3 mm continuum sources are revealed,…

An important tracer of the origin and evolution of cometary ices is the comparison with ices found in dense clouds and towards Young Stellar Objects (YSOs). We present a survey of ices in the 2-5 micron spectra of 23 massive YSOs, taken…

星系天体物理 · 物理学 2022-12-29 A. C. A. Boogert , K. Brewer , A. Brittain , K. S Emerson

We have undertaken a Parkes ammonia spectral line study, in the lowest two inversion transitions, of southern massive star formation regions, including young massive candidate protostars, with the aim of characterising the earliest stages…

太阳与恒星天体物理 · 物理学 2015-05-14 T. Hill , S. N. Longmore , C. Pinte , M. R. Cunningham , M. G. Burton , V. Minier

We present a survey of OH maser emission towards a sample of high mass protostellar objects made using the Nancay and GBT telescopes.OH maser emission was detected towards 63 objects with 36 new detections. There are 56 star-forming regions…

天体物理学 · 物理学 2009-11-13 K. A. Edris , G. A. Fuller , R. J . Cohen

NGC 253 hosts the nearest nuclear starburst. Previous observations show a region rich in molecular gas, with dense clouds associated with recent star formation. We used ALMA to image the 350 GHz dust continuum and molecular line emission…

We characterize the molecular environment of candidate massive young stellar objects (MYSOs) signposted by methanol masers. Single pixel observations of 10 transitions of HCO^+, CO and CS isotopomers were carried out, using the IRAM 30m…

天体物理学 · 物理学 2009-11-13 M. Szymczak , A. Bartkiewicz , A. M. S. Richards

We present the results of millimeter and centimeter continuum observations, made with the IRAM 30m telescope and the VLA, toward a sample of 11 luminous IRAS sources classified as high-mass protostellar object candidates. We find 1.2 mm…

天体物理学 · 物理学 2009-11-13 Á. Sánchez-Monge , A. Palau , R. Estalella , M. T. Beltrán , J. M. Girart

NGC 281 is a complex region of star formation at 2.8 kpc. This complex is situated 300 pc above the Galactic plane, and appears to be part of a 270 pc diameter ring of atomic and molecular clouds expanding at 22 km/s (Megeath et al. 2003).…

太阳与恒星天体物理 · 物理学 2018-05-22 Priya Hasan

We report the results of subparsec-scale submillimeter observations towards an embedded high-mass young stellar object in the Small Magellanic Cloud (SMC) with ALMA. Complementary infrared data obtained with the AKARI satellite and the…

We present a survey for water maser emission toward a sample of 44 low-luminosity young objects, comprising (proto-)brown dwarfs, first hydrostatic cores (FHCs), and other young stellar objects (YSOs) with bolometric luminosities lower than…

太阳与恒星天体物理 · 物理学 2017-04-26 Jose F. Gomez , Aina Palau , Lucero Uscanga , Guillermo Manjarrez , David Barrado

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…

星系天体物理 · 物理学 2015-05-18 S. V. Kalenskii , L. E. B. Johansson , P. Bergman , S. Kurtz , P. Hofner , C. M. Walmsley , V. I. Slysh

Evidence for a large scale flow of low density gas onto the Cepheus A young stellar cluster is presented. Observations of K-band near-infrared and multi-transition CS and N2H+ millimeter line emission are shown in relation to a…

天体物理学 · 物理学 2009-11-10 Sandrine Bottinelli , Jonathan P. Williams