Related papers: Finding Distant Galactic HII Regions

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…

The southern Galactic high mass star-forming region, G351.6-1.3, is a HII region-molecular cloud complex with a luminosity of 2.0 x 10^5 L_sun, located at a distance of 2.4 kpc. In this paper, we focus on the investigation of the associated…

HII regions and planetary nebulae (PNe) both emit at radio and infrared (IR) wavelengths, and angularly small HII regions can be mistaken for PNe. This problem of classification is most severe for HII regions in an early evolutionary stage,…

We present an HI absorption survey of the central 250 pc of the Galaxy. Very Large Array (VLA) observations were made at 21 cm in the DnC and CnB configurations and have a resolution of ~15"(0.6 pc at the Galactic Center (GC) distance) and…

Radio continuum surveys of the Galactic plane can find and characterize HII regions, supernova remnants (SNRs), planetary nebulae (PNe), and extragalactic sources. A number of surveys at high angular resolution (<25") at different…

Spectrophotometric distances in the K band have been reported by different authors for a number of obscured Galactic HII regions. Almost 50% of them show large discrepancies compared to the classical method using radial velocities measured…

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…

We have observed the compact HII region complex nearest to the dynamical center of the Galaxy, G-0.02-0.07, using ALMA in the H42a recombination line, CS J=2-1, H13CO+ J=1-0, and SiO v=0, J=2-1 emission lines, and 86 GHz continuum emission.…

We report radio recombination line (RRL) and continuum observations of a sample of 106 Galactic HII regions made with the NRAO 140 Foot radio telescope in Green Bank, WV. We believe this to be the most sensitive RRL survey ever made for a…

To interpret the galactic center H II region complexes as constituents of a barred galaxy's nuclear star-forming ring, we compare 18cm VLA radiocontinuumm, $8-22\mu$ MSX IR and 2.6mm BTL and ARO12m CO emission in the inner few hundred pc.…

We present new criteria for selecting HII regions from the Infrared Astronomical Satellite (IRAS) Point Source catalogue (PSC), based on an HII region catalogue derived manually from the all-sky Wide-field Infrared Survey Explorer (WISE).…

The spiral structure of the Milky Way is not conclusive, even for the disc regions in the solar neighbourhood. Especially, the arm-like structures uncovered from the over-density maps of evolved stars are inconsistent with the commonly…

The Galactic HII region luminosity function (LF) is an important metric for understanding global star formation properties of the Milky Way, but only a few studies have been done and all use relatively small numbers of HII regions. We use a…

We present new radio recombination line observations of the previously unstudied HII region CTB 102. Line parameters are extracted and physical parameters describing the gas are calculated. We estimate the distance to CTB 102 to be 4.3 kpc.…

A new class of extragalactic astronomical sources discovered in 2021, named Odd Radio Circles (ORCs, Norris et al. 2021), are large rings of faint, diffuse radio continuum emission spanning ~1 arcminute on the sky. Galaxies at the centers…

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…

We present radio continuum images of three Galactic HII regions, S 201, S 206, and S 209 near 232, 327, and 610 MHz using the Giant Meterwave Radio Telescope (GMRT). The GMRT has a mix of short and long baselines, therefore, even though the…

The Southern HII Region Discovery Survey (SHRDS) is a survey of the third and fourth quadrants of the Galactic plane that will detect radio recombination line and continuum emission at cm-wavelengths from several hundred HII region…

We present radio and infrared observations of 4 hyper-compact HII regions and 4 ultra-compact HII regions in the southern Galactic plane. These objects were selected from a blind survey for UCHII regions using data from two new radio…

We investigate the star formation activity in the molecular complex associated with the Galactic HII region Sh2-90, using radio-continuum maps obtained at 1280 MHz and 610 MHz, Herschel Hi-GAL observations at 70 -- 500 microns, and deep…