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We present 7mm Very Large Array continuum images of the starburst galaxy M82. On arcsecond scales, two-thirds of the 7mm continuum consists of free-free emission from HII regions. In the subarcsecond resolution map, we identify 14 compact…

Cosmology and Nongalactic Astrophysics · Physics 2009-11-13 Chao-Wei Tsai , Jean L. Turner , Sara C. Beck , David S. Meier , Paul T. P. Ho

We present a multiwavelength study of the ultra compact HII region associated with IRAS 20178+4046. This enables us to probe the different components associated with this massive star forming region. The radio emission from the ionized gas…

Astrophysics · Physics 2009-11-13 A. Tej , S. K. Ghosh , V. K. Kulkarni , D. K. Ojha , R. P. Verma , S. Vig

We present deep 3.6 cm radio continuum observations of the H II region NGC 2024 in Orion B obtained using the Very Large Array in its A-configuration, with $0\rlap.{''}2$ angular resolution. We detect a total of 25 compact radio sources in…

Astrophysics · Physics 2009-11-10 Luis F. Rodriguez , Yolanda Gomez , Bo Reipurth

A handful of HII regions are known to exhibit a compact radio source near their centers. The nature of these compact radio sources is not well established. We present the analysis of new as well as archival Very Large Array observations of…

Solar and Stellar Astrophysics · Physics 2013-12-11 Luis F. Rodríguez , Josep M. Masqué , Sergio A. Dzib , Laurent Loinard , Stanley E. Kurtz

We have obtained 8.4 GHz VLBA observations of a 31-GHz complete sample of ~100 sources between 10 and 100 mJy. The main goals of these observations are: to determine the angular size, radio spectra and identification for a weak sample of…

Astrophysics · Physics 2008-06-19 W. A. Majid , E. B. Fomalont , D. S. Bagri

We present an HI 21cm absorption study of a sample of 26 radio-loud active galactic nuclei (AGN) at $0.25 < z < 0.4$ carried out with the Karl G. Jansky Very Large Array. Our aim was to study the rate of incidence of HI in various classes…

Astrophysics of Galaxies · Physics 2021-10-20 Suma Murthy , Raffaella Morganti , Tom Oosterloo , Filippo M. Maccagni

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 high-resolution radio observations of a sample of 65 radio sources at low Galactic latitudes. The sources were all observed at 5 GHz with the Very Large Array A-array. MERLIN observations at 5 GHz of the ultracompact HII region…

Astrophysics · Physics 2009-11-10 D. J. Saikia , P. Thomasson , S. Roy , A. Pedlar , T. W. B. Muxlow

We present a deep centimeter-wavelength catalog of the Orion Nebula Cluster (ONC), based on a 30h single-pointing observation with the Karl G. Jansky Very Large Array in its high-resolution A-configuration using two 1 GHz bands centered at…

We present 115 compact radio point sources in three galaxies, NGC 5474, NGC 4631 and M51, taken in the most extended (A-)configuration of the Karl G. Jansky Very Large Array at 10GHz. Several of these compact radio point sources have…

We utilize new VLA Galactic plane catalogs at 5 and 1.4 GHz covering the first Galactic quadrant (350<l<42, |b|<0.4) in conjunction with the MSX6C Galactic plane catalog to construct a large sample of ultra-compact HII regions. A radio…

Astrophysics · Physics 2009-11-10 Uriel Giveon , Robert H. Becker , David J. Helfand , Richard L. White

We report subarcsecond-resolution VLA imaging of the centers of four nearby spiral galaxies: IC 342, Maffei II, NGC 2903, and NGC 6946. In each galaxy, 7 - 12 compact radio continuum sources were identified within the central 15" x 15".…

To try and confirm the types of object in the list of 2298 potential HII regions identified by Hughes \& MacLeod from the IRAS Point Source Catalog, we selected a sample of 82 for observing at the VLA. We selected half with values of Y =…

Astrophysics · Physics 2009-10-22 V. A. Hughes , G. C. MacLeod

We analyze high-resolution Very Large Array and Jansky Very Large Array continuum observations of the M8 region carried out at several epochs that span a period of 30 yr. Our maps reveal two compact sources. One is associated with Her 36…

Solar and Stellar Astrophysics · Physics 2015-06-23 Josep Maria Masqué , Sergio Dzib , Luís Felipe Rodríguez

Large-scale radio continuum surveys provide data to get insights into the physical properties of radio sources. HII regions are prominent radio sources produced by thermal emission of ionised gas around young massive stars. We identify and…

Astrophysics of Galaxies · Physics 2019-03-13 X. Y. Gao , P. Reich , L. G. Hou , W. Reich , J. L. Han

We present and discuss a new catalogue of 52 compact HII regions in the Small Magellanic Cloud (SMC) and a newly created deep 1420 MHz (\lambda=20 cm) radio-continuum image of the N19 region located in the southwestern part of the SMC. The…

Cosmology and Nongalactic Astrophysics · Physics 2013-02-06 G. F. Wong , M. D. Filipovic , E. J. Crawford , N. F. H. Tothill , A. Y. De Horta , T. J. Galvin

We present a detailed characterization of the population of compact radio-continuum sources in W51 A using subarcsecond VLA and ALMA observations. We analyzed their 2-cm continuum, the recombination lines (RL's) H77$\alpha$ and H30$\alpha$,…

Astrophysics of Galaxies · Physics 2020-08-26 Rudy Rivera-Soto , Roberto Galván-Madrid , Adam Ginsburg , Stan Kurtz

We present the results from two radio integrations at 8.4 GHz using the VLA. One of the fields, at 13h,+43d (SA13 field), has an rms noise level of 1.49 microJy and is the deepest radio image yet made. Thirty-four sources in a complete…

We present a SCUBA submillimetre (450 & 850 micron) survey of the environment of 105 IRAS point sources, selected from the Wood & Churchwell (1989a) and Kurtz, Churchwell & Wood (1994) radio ultracompact (UC) HII region surveys. We detected…

Astrophysics · Physics 2009-11-11 M. A. Thompson , J. Hatchell , A. J. Walsh , G. H. Macdonald , T. J. Millar

We have determined detailed radio spectra for 26 compact sources in the starburst nucleus of M82, between 74 and 1.3 cm. Seventeen show low-frequency turnovers. One other has a thermal emission spectrum, and we identify it as an HII region.…

Astrophysics · Physics 2009-10-30 Michael L. Allen , Philipp P. Kronberg