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Related papers: A search for hypercompact HII regions in the Galac…

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We present a complete catalog of H I emission and absorption spectrum pairs, toward H II regions, detectable within the boundaries of the Southern Galactic Plane Survey (SGPS I), a total of 252 regions. The catalog is presented in…

Astrophysics of Galaxies · Physics 2015-06-18 C Brown , J. M. Dickey , J. R. Dawson , N. M. McClure-Griffiths

We study the physical and chemical properties of a sample of HII regions located at RG >11 kpc and present the radial distribution of abundances towards the Galaxy anticentre. We carried out optical spectroscopic observations of nine HII…

Astrophysics of Galaxies · Physics 2017-01-18 Alba Fernández-Martín , Enrique Pérez-Montero , José Manuel Vílchez , Antonio Mampaso

Our goal is to identify bipolar HII regions and to understand their morphology, their evolution, and the role they play in the formation of new generations of stars. We use the Spitzer and Herschel Hi-GAL surveys to identify bipolar HII…

We present our fifth set of results from our mid-infrared imaging survey of Milky Way Giant HII (GHII) regions with our detailed analysis of DR7 and K3-50. We obtained 20/25 and 37um imaging maps of both regions using the FORCAST instrument…

Astrophysics of Galaxies · Physics 2023-06-07 James M. De Buizer , Wanggi Lim , James T. Radomski , Mengyao Liu

The Very Small Array (VSA) has been used to survey the l = 27 to 46 deg, |b|<4 deg region of the Galactic plane at a resolution of 13 arcmin. The survey consists of 44 pointings of the VSA, each with a r.m.s. sensitivity of ~90 mJy/beam.…

In a first of a series of studies of the H-alpha + [NII] emission from nearby spiral galaxies, we present measurements of H-alpha + [NII] emission from HII regions in M81. Our method uses large-field-CCD images and long-slit spectra, and is…

Astrophysics · Physics 2009-11-07 W. P. Lin , X. Zhou , D. Burstein , R. A. Windhorst , J. S. Chen

We present K-band spectra of newly born OB stars in the obscured Galactic giant H II region W51A and ~ 0.8'' angular resolution images in the J, H and K_S-bands. Four objects have been spectroscopically classified as O-type stars. The mean…

Astrophysics · Physics 2009-11-13 E. Figueredo , R. D. Blum , A. Damineli , P. S. Conti , C. L. Barbosa

The classic HII region M17 is one of the best studied across the electromagnetic spectrum. We present sensitive, high angular resolution observations made with the Jansky Very Large Array (JVLA) at 4.96 and 8.46 GHz that reveal the presence…

Solar and Stellar Astrophysics · Physics 2015-06-05 Luis F. Rodriguez , Ricardo F. Gonzalez , Gabriela Montes , Hassan M. Asiri , Alejandro C. Raga , Jorge Canto

We derive the synchrotron distribution in the Milky Way disk from HII region absorption observations over -40{\deg} < l < 40{\deg} at six frequencies of 76.2, 83.8, 91.5, 99.2, 106.9, and 114.6 MHz with the GaLactic and Extragalactic…

High-mass stars form in much richer environments than those associated with isolated low-mass stars, and once they reach a certain mass, produce ionised (HII) regions. The formation of these pockets of ionised gas are unique to the…

We aim to investigate the chemistry of internal photon-dominated regions surrounding deeply embedded hypercompact and ultracompact HII regions. We search for specific tracers of this evolutionary stage of massive star formation that can be…

This paper is the first in a series presenting CCD multicolor photometry for 145 HII regions, selected from 369 candidate regions from Boulesteix et al. (1974), in the nearby spiral galaxy M33. The observations, which covered the whole area…

Astrophysics · Physics 2009-11-07 Linhua Jiang , Jun Ma , Xu Zhou , Jiansheng Chen , Hong Wu , Zhaoji Jiang , Suijian Xue , Jin Zhu

Three Galactic HII regions, viz., S 201, S 206, and S 209 have been imaged at three frequencies, viz., 232, 327, and 610 MHz using the GMRT. The resolutions of these images are typically 15" at 232, 10" at 327, and 6" at 610 MHz. These are…

Astrophysics · Physics 2007-05-23 Amitesh Omar , J. N. Chengalur , D. A. Roshi

We present Very Large Array 7 mm continuum observations of four Ultra-Compact (UC)HII regions, observed previously at 1.3 cm, in order to investigate the nature of the compact radio sources associated with these regions. We detected a total…

The HII regions around quasars and galaxies at redshifts beyond the epoch of reionisation will provide prime targets for upcoming 21cm campaigns using a new generation of low-frequency radio observatories. Here we show that the boundaries…

Astrophysics · Physics 2015-06-24 Stuart Wyithe , Abraham Loeb

In this paper we present the results of a morphological study performed on a sample of 28 ultracompact \hiirs~located near extended free-free emission, using radio continuum observations at 3.6~cm with the C and D VLA~configurations, with…

A re-analysis of the radio continuum emission from circumnuclear regions of the barred galaxies NGC 1022, 1326 & 4314 is presented. The spatial distributions of Halpha and radio continuum are similar and suggest the existence of several…

Astrophysics · Physics 2009-10-31 Jose Franco , J. Antonio Garcia-Barreto , Eduardo de la Fuente

We present a study of the close (< 200 kpc) environment of 110 relatively local (z< 0.16) HII galaxies, selected from the Sloan Digital Sky Survey (SDSS; DR7). We use available spectroscopic and photometric redshifts in order to investigate…

Cosmology and Nongalactic Astrophysics · Physics 2014-07-17 E. Koulouridis , M. Plionis , R. Chávez , E. Terlevich , R. Terlevich , F. Bresolin , S. Basilakos

We present our third set of results from our mid-infrared imaging survey of Milky Way Giant HII (GHII) regions with our detailed analysis of W49A, one of the most distant, yet most luminous, GHII regions in the Galaxy. We used the FORCAST…

Astrophysics of Galaxies · Physics 2022-01-05 James M. De Buizer , Wanggi Lim , Mengyao Liu , Nicole Karnath , James Radomski

Here we present a brief overview of UC HII regions with EE (UC HII+EE) including our most recent effort aimed at searching for UC HII regions associated with extended emission.

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