相关论文: Comments on the radio spectrum of HB 3

Evidence for a spectral flattening of the supernova remnant (SNR) HB3 (G132.7+1.3) was recently claimed in literature based on previously published total flux density data, and the flattening was further interpreted as the discovery of…

We present an analysis of the broadband radio spectrum (from 22 to 3900 MHz) of the Galactic supernova remnant (SNR) HB3 (G132.7+1.3). Published observations have revealed that a curvature is present in the radio spectrum of this SNR,…

We present images of the SNR HB3 at both 408 MHz and 1420 MHz from the Canadian Galactic Plane Survey mainly based on data from the Synthesis Telescope of the Dominion Radio Astrophysical Observatory. We reproduce the 100m-Effelsberg HB3…

It has recently been reported that some of the flux density values for an evolved supernova remnant (SNR) HB 3 (G132.7 + 1.3) are not accurate. In this work we revised an analysis of the possible thermal emission at radio frequencies from…

We use observations of the continuum radio emission at 1420, 820, 408, 34.5 and 22 MHz to estimate the mean brightness temperatures of the HB 21 supernova remnant (SNR) at five frequencies. We also presented mean spectral index of HB 21.…

We present new radio continuum observations of NGC253 from the Murchison Widefield Array at frequencies between 76 and 227 MHz. We model the broadband radio spectral energy distribution for the total flux density of NGC253 between 76 MHz…

We study the radio spectral properties of 2,094 star-forming galaxies (SFGs) by combining our early science data from the MeerKAT International GHz Tiered Extragalactic Exploration (MIGHTEE) survey with VLA, GMRT radio data, and rich…

New images of the Supernova Remnants (SNRs) G114.3+0.3, G116.5+1.1 and G116.9+0.2 (CTB 1) are presented at 408 MHz from the Canadian Galactic Plane Survey (CGPS). We also use the 1420 MHz images from the CGPS to study their 408-1420 MHz…

We present total flux densities of 1049 radio sources in the frequency range from 151 MHz to 10.6 GHz. These sources belong to the B3-VLA sample, which is complete down to 100 mJy at 408 MHz. The data constitute a homogeneous spectral…

We present radio maps of the historical supernova remnant G11.2-0.3 in the frequency range from 4.85 GHz to 32 GHz. The integrated spectrum with \alpha = -0.50 (S ~ \nu^\alpha) is dominated by its steep spectrum shell emission (\alpha ~…

A considerable fraction of Galactic supernova remnants (SNRs) characterize flat spectral indices ($\alpha<0.5$). There are several explanations of the flat radio spectra of SNRs in the present literature. The most of models involve a…

We present the analysis of Fermi Large Area Telescope (LAT) $\gamma$-ray observations of HB~21 (G89.0+4.7). We detect significant $\gamma$-ray emission associated with the remnant: the flux >100 MeV is…

The radio continuum spectra of 14 star-forming galaxies are investigated by fitting nonthermal (synchrotron) and thermal (free-free) radiation laws. The underlying radio continuum measurements cover a frequency range of ~325 MHz to 24.5 GHz…

Resonant scattering of He I 1.0833$\mu$m triplet photons by metastable He 2 $^3$S$_1$ is studied for optical depths characteristic of H II regions. Regions with large He 2 $^3$S$_1$ column densities are predicted to have unusually broad,…

We have conducted a deep radio survey with the Very Large Array at 1.4 GHz of a region containing the Hubble Deep Field. This survey overlaps previous observations at 8.5 GHz allowing us to investigate the radio spectral properties of…

The supernova remnant (SNR) G25.1-2.3 was identified in the radio band during the Sino-German $\lambda$6 cm survey of the Galactic plane. We present a detailed investigation of the optical, HI, and CO emission towards the G25.1-2.3 to…

Radio continuum emission from galaxies at gigahertz frequencies can be used as an extinction-free tracer of star formation. However, at frequencies of a few hundred megahertz, there is evidence for low-frequency spectral flattening. We wish…

Deep H$\alpha$ images of a faint emission complex 4.0 x 5.5 degrees in angular extent and located far off the Galactic plane at l = 70.0 degrees, b=-21.5 degrees reveal numerous thin filaments suggestive of a supernova remnant's shock…

Deep optical CCD images of the supernova remnant G 15.1-1.6 were obtained and filamentary and diffuse emission has been discovered. The images, taken in the emission lines of Halpha+[N II], [S II] and [O III], reveal filamentary and diffuse…

We present a sample of sources with convex radio spectra peaking at frequencies above a few GHz, known as "High Frequency Peakers" (HFPs). A "bright" sample with a flux density limit of 300 mJy at 5 GHz has been presented by Dallacasa et…