Related papers: Radio Recombination Line Observations at $1.0-1.5$…
We observed radio recombination lines (RRLs) toward the W51 molecular cloud complex, one of the most active star forming regions in our Galaxy. The UV radiation from young massive stars ionizes gas surrounding them to produce HII regions.…
HII regions are the ionized spheres surrounding high-mass stars. They are ideal targets for tracing Galactic structure because they are predominantly found in spiral arms and have high luminosities at infrared and radio wavelengths. In the…
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…
Previous radio recombination line (RRL) observations of dust clumps identified in the APEX Telescope Large Area Survey of the Galaxy (ATLASGAL) have led to the detection of a large number of RRLs in the 3mm range. Here, we aim to study…
We report the detection of stimulated hydrogen radio recombination line (RRL) emission from ionized gas in a $z=0.89$ galaxy using 580--1670 MHz observations from the MeerKAT Absorption Line Survey (MALS). The RRL emission originates in a…
Radio recombination lines (RRL) at 8 GHz and 15 GHz detected from four starburst galaxies are shown to arise in compact high density HII regions, which are undetectable below ~4 GHz. Detection of an RRL at 1.4 GHz towards one galaxy and…
As part of our ongoing HII Region Discovery Survey (HRDS), we report the Green Bank Telescope detection of 148 new angularly-large Galactic HII regions in radio recombination line (RRL) emission. Our targets are located at a declination…
We report multifrequency radio continuum and hydrogen radio recombination line observations of HII regions near l=24.8d b=0.1d using the Giant Metrewave Radio Telescope (GMRT) at 1.28 GHz (n=172), 0.61 GHz (n=220) and the Very Large Array…
The Green Bank Telescope HII Region Discovery Survey has doubled the number of known HII regions in the Galactic zone 343deg.\leql\leq67deg. with |b|\leq1deg. We detected 603 discrete hydrogen radio recombination line (RRL) components at…
We investigate the kinematic properties of Galactic HII regions using radio recombination line (RRL) emission detected by the Australia Telescope Compact Array (ATCA) at 4-10 GHz and the Jansky Very Large Array (VLA) at 8-10 GHz. Our HII…
The census of Galactic HII regions is vastly incomplete in the Southern sky. We use the Australia Telescope Compact Array (ATCA) to observe 4-10 GHz radio continuum and hydrogen radio recombination line (RRL) emission from candidate HII…
Studies of Galactic HII regions are of crucial importance for studying star formation and the evolution of the interstellar medium. Gaining an insight into their physical characteristics contributes to a more comprehensive understanding of…
We present a Radio Recombination Line (RRL) survey of the Galactic Plane from the HI Parkes All-sky Survey and associated Zone of Avoidance survey, which mapped the region l=196degr -- 0degr --52degr and |b| < 5degr at 1.4 GHz and 14.4…
Diffuse ionized gas pervades the disk of the Milky Way. We detect extremely faint emission from this Galactic Warm Ionized Medium (WIM) using the Green Bank Telescope to make radio recombination line (RRL) observations toward two Milky Way…
Hydrogen recombination lines (HRLs) are valuable diagnostics of the physical conditions in ionized regions around high-mass stars. Understanding their broadening mechanisms and intensity trends can provide insights into the densities,…
We report the discovery of hydrogen radio recombination line (RRL) emission from two galaxies with star formation rates (SFRs) similar to that of the Milky Way: M51 and NGC628. We use the Green Bank Telescope (GBT) to measure $\sim$15…
As one of the major components of the interstellar medium, the ionized gas in our Milky Way, especially the low-density diffuse component, has not been extensively observed in the radio band. The Galactic Plane Pulsar Snapshot (GPPS) survey…
We report the first detection of radio recombination lines (RRLs) of ions heavier than helium. In a highly sensitive multi-band (12--50 GHz) line survey toward Orion KL with the TianMa 65-m Radio Telescope (TMRT), we successfully detected…
We performed a radio recombination line (RRL) survey to construct a high-mass star-forming region (HMSFR) sample in the Milky Way based on the all-sky Wide-Field Infrared Survey Explorer ($\textit{All-WISE}$) point source catalog. The…
Observations of millimeter wavelength radio recombination lines (mm-RRLs) are used to search for HII regions in an unbiased way that is complementary to many of the more traditional methods previously used. We carried out targeted mm-RRL…