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The star-forming activity in the HII region RCW 42 is investigated using multiple wavebands, from near-infrared to radio wavelengths. Located at a distance of 5.8 kpc, this southern region has a bolometric luminosity of 1.8 $\times$ 10$^6$…

Astrophysics of Galaxies · Physics 2022-08-17 Vipin Kumar , S. Vig , V. S. Veena , S. Mohan , S. K. Ghosh , A. Tej , D. K. Ojha

Previous HST and FUSE observations have revealed highly ionized high-velocity clouds (HVCs) or more generally low HI column HVCs along extragalactic sightlines over 70-90% of the sky. The distances of these HVCs have remained largely…

Astrophysics of Galaxies · Physics 2015-05-14 N. Lehner , J. C. Howk

We present deep echelle spectrophotometry of the brightest emission-line knots of the star-forming galaxies He 2-10, Mkn 1271, NGC 3125, NGC 5408, POX 4, SDSS J1253-0312, Tol 1457-262, Tol 1924-416 and the HII region Hubble V in the Local…

Astrophysics of Galaxies · Physics 2015-06-22 C. Esteban , J. García-Rojas , L. Carigi , M. Peimbert , F. Bresolin , A. R. López-Sánchez , A. Mesa-Delgado

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

We report the detection of a new radio recombination line (RRL) maser object toward the IRS2 source in the MonR2 ultracompact HII region. The continuum emission at 1.3mm and 0.85mm and the H30a and H26a lines were observed with the…

Solar and Stellar Astrophysics · Physics 2015-06-12 I. Jimenez-Serra , A. Baez-Rubio , V. M. Rivilla , J. Martin-Pintado , Q. Zhang , M. Dierickx , N. Patel

We analyze the distribution of the interstellar matter in the environs of the HII region Gum31, excited by the open cluster NGC3324, located in the complex Carina region, with the aim of investigating the action of the massive stars on the…

Astrophysics · Physics 2009-11-13 C. Cappa , V. S. Niemela , R. Amorin , J. Vasquez

We report subarcsecond-resolution VLA imaging of four nearby spiral galaxies: IC 342, Maffei II, NGC 2903, and NGC 6946. In each galaxy, compact radio continuum sources are identified in the central ~ 15" x 15" region. These compact sources…

The location of HII regions, which indicates the locus of present star formation in galaxies, is analyzed for a large collection of 110 irregular galaxies (Irr) imaged in H$\alpha$ and nearby continuum. The analysis is primarily by visual…

Astrophysics · Physics 2015-06-24 Noah Brosch , Ana Heller , Elchanan Almoznino

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…

Spectral line and continuum observations of the ionized and molecular gas in G20.08-0.14 N explore the dynamics of accretion over a range of spatial scales in this massive star-forming region. Very Large Array observations of NH_3 at 4''…

Astrophysics of Galaxies · Physics 2015-05-14 Roberto Galván-Madrid , Eric Keto , Qizhou Zhang , Stan Kurtz , Luis F. Rodríguez , Paul T. P. Ho

As part of a systematic study that we are performing with the aim to increase the observational evidence of triggered star formation in the surroundings of HII regions, we analyze the ISM around the HII region G35.673-00.847, a poorly…

Astrophysics of Galaxies · Physics 2015-05-20 S. Paron , A. Petriella , M. E. Ortega

By using the Hectospec 6.5 m Multiple Mirror Telescope (MMT) and the 2.16 m telescope of National Astronomical Observatories, Chinese Academy of Sciences (NAOC), we obtained 188 high signal-to-noise ratio (S/N) spectra of HII regions in the…

Astrophysics of Galaxies · Physics 2018-03-21 Ning Hu , Enci Wang , Zesen Lin , Xu Kong , Fuzhen Cheng , Zou Fan , Guanwen Fang , Lin Lin , Yewei Mao , Jing Wang , Xu Zhou , Zhiming Zhou , Yinan Zhu , Hu Zou

A sample of 69 galaxies with radial velocities less than 2500 km/s was selected from the HI Parkes All Sky Survey (HIPASS) to deduce details about star formation in nearby disk galaxies selected with no bias to optical surface brightness…

Astrophysics · Physics 2009-11-11 J. F. Helmboldt , R. A. M. Walterbos , G. D. Bothun , K. O'Neil

In this contribution we explore the new science that a Next Generation Very Large Array (ngVLA) would be able to perform on the topics of the youngest HII regions and (proto)stellar jets. Free-free continuum and radio recombination line…

We present high angular resolution (0.6'') observations made with the VLA of the radio continuum at 8.3 and 43 GHz as well as H92 Alpha and H53 Alpha radio recombination lines from the nearby (3 Mpc) starburst galaxy M82. In the continuum…

We have searched for HI 21 cm line emission from shocked atomic gas associated with southern supernova remnants (SNRs) using data from the Southern Galactic Plane Survey. Among the 97 sources studied, we have detected 10 SNRs with…

Astrophysics · Physics 2017-01-18 Bon-Chul Koo , Ji-hyun Kang , N. M. McClure-Griffiths

Observations of ionized and neutral gas outflows in radio-galaxies (RGs) suggest that AGN radio jet feedback has a galaxy-scale impact on the host ISM, but it is still unclear how the molecular gas is affected. We present deep Spitzer IRS…

Cosmology and Nongalactic Astrophysics · Physics 2015-06-03 Pierre Guillard , Patrick Ogle , Bjorn Emonts , Philip Appleton , Raffaella Morganti , Clive Tadhunter , Tom Oosterloo , Dan Evans , Aaron Evans

The emission line ratios [OIII]5007/H-beta and [NII]6584/H-alpha have been adopted as an empirical way to distinguish between the fundamentally different mechanisms of ionization in emission-line galaxies. However, detailed interpretation…

Cosmology and Nongalactic Astrophysics · Physics 2015-06-15 Sherry C. C. Yeh , Silvia Verdolini , Mark R. Krumholz , Christopher D. Matzner , Alexander G. G. M. Tielens

(Abridged) We present the results of three-dimensional radiation-hydrodynamics simulations of the formation and evolution of early HII/HeIII regions around the first stars. Cooling (by H2 and HD) and recollapse of the gas in the relic HII…

Astrophysics · Physics 2008-11-26 Naoki Yoshida , S. Peng Oh , Tetsu Kitayama , Lars Hernquist

(abridged) We present deep spectroscopy of a large sample of low-metallicity emission-line galaxies. The main goal of this study is to derive element abundances in these low-metallicity galaxies. We analyze 121 VLT spectra of HII regions in…

Cosmology and Nongalactic Astrophysics · Physics 2011-11-08 N. G. Guseva , Y. I. Izotov , G. Stasinska , K. J. Fricke , C. Henkel , P. Papaderos