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3171. Compact HII regions IR photometry
ID:
ivo://CDS.VizieR/J/MNRAS/391/1527
Title:
Compact HII regions IR photometry
Short Name:
J/MNRAS/391/1527
Date:
21 Oct 2021
Publisher:
CDS
Description:
We present 3.6, 4.5, 5.8 and 8.0um photometry and mapping for 58 compact HII regions identified using the Spitzer Galactic Legacy Infrared Midplane Survey Extraordinaire (GLIMPSE). These are used to investigate trends in the colours, magnitudes and structures of the sources, together with spatial variations in flux ratio. It is concluded that most of the sources are remarkably similar, and have comparable variations in flux ratio as a function of position within the shells, together with very narrowly defined ranges of colour index.
3172. Compact radio cores in radio galaxies.
ID:
ivo://CDS.VizieR/J/MNRAS/268/602
Title:
Compact radio cores in radio galaxies.
Short Name:
J/MNRAS/268/602
Date:
21 Oct 2021
Publisher:
CDS
Description:
This catalog contains compact core fluxes for a list of 175 southern radio galaxies, measured with the Parkes-Tidbinbilla Interferometer (PTI, Norris et al. 1988ApJS...67...85N) on a single 275 km baseline at 2.3 GHz and 8.4 GHz. The sample consists of large angular size ( > 0.5 arcmin) steep spectrum sources from Jones & McAdam (1992ApJS...80..137J) observed to determine the fraction of flux contained in compact (VLBI-scale) cores. Of the 172 sources observed at 2.3 GHz (100 milliarcsec fringe spacing), 63 had cores detected and upper limits were determined for the remaining 109. Of the 88 sources observed at 8.4 GHz (30 milliarcsec fringe spacing), 38 had cores detected and 50 have upper limits. A comparison of the detections and upper limits at the two frequencies shows that the cores have flat or inverted spectra. The core fluxes quoted here may vary by around 20 % if there is structure on the scale of the fringe spacing and the cores are probably intrinsically variable.
3173. Compact radio sources at -30<Dec<0
ID:
ivo://CDS.VizieR/J/ApJS/145/83
Title:
Compact radio sources at -30<Dec<0
Short Name:
J/ApJS/145/83
Date:
21 Oct 2021
Publisher:
CDS
Description:
We present a catalog of 321 compact radio sources in the declination range 0{deg}>{delta}>-30{deg}. The positions of these sources have been measured with a two-dimensional rms accuracy of 35milliarcseconds using the NRAO Very Large Array. Each source has a peak flux density >50mJy at 8.4GHz. We intend for this catalog to be used mainly for selection of phase calibration sources for radio interferometers, although compact radio sources have other scientific uses.
3174. Compact Radio Sources in & behind LMC catalogue
ID:
ivo://CDS.VizieR/J/A+AS/126/325
Title:
Compact Radio Sources in & behind LMC catalogue
Short Name:
J/A+AS/126/325
Date:
21 Oct 2021
Publisher:
CDS
Description:
We present the results of a continuum snapshot survey of a 3x4{deg}^2^ region of the Large Magellanic Cloud including the area of the giant molecular cloud and the 30 Doradus nebula. The observations have been carried out with the Australia Telescope Compact Array (ATCA) at 1.4 and 2.4GHz. Most fields are complete to about 6mJy peak flux density at 1.4GHz and to about 3mJy at 2.4GHz. The positions, peak and integral flux densities of 113 compact (<54") sources detected at 1.4GHz and of 70 sources (<34") detected at 2.4GHz are presented. Positions are accurate to about 3" and peak flux densities are accurate to about 10% or better, depending on the source position relative to the pointing centers. 32 of the sources detected at 1.4GHz are coincident with H{alpha} objects in the catalogue of Davies, Elliot and Meaburn (1976MmRAS..81...89D); these are possibly intrinsic to the LMC. However, we suppose that most are background objects, since the number vs. flux agrees with predictions of extragalactic source counts from other surveys.
3175. Compact radio sources in NGC 6334D to F
ID:
ivo://CDS.VizieR/J/A+A/610/A27
Title:
Compact radio sources in NGC 6334D to F
Short Name:
J/A+A/610/A27
Date:
21 Oct 2021
Publisher:
CDS
Description:
The presence and properties of compact radio sources embedded in massive star forming regions can reveal important physical properties about these regions and the processes occurring within them. The NGC 6334 complex, a massive star forming region, has been studied extensively. Nevertheless, none of these studies has focused in its content in compact radio sources. Aims. Our goal here is to report on a systematic census of the compact radio sources toward NGC 6334, and their characteristics. This will be used to attempt to define their very nature. We used the VLA C band (4-8GHz) archive data with 0.36" (500AU) of spatial resolution and noise level of 50Jy/bm to carry out a systematic search for compact radio sources within NGC 6334. We also searched for infrared counterparts to provide some constraints on the nature of the detected radio sources. A total of 83 compact sources and three slightly resolved sources were detected. Most of them are here reported for the first time. We found that 29 of these 86 sources have infrared counterparts and three are highly variable. Region D contains 18 of these sources. The compact source toward the center, in projection, of region E is also detected. From statistical analyses, we suggest that the 83 reported compact sources are real and most of them are related to NGC 6334 itself. A stellar nature for 27 of them is confirmed by their IR emission. Compared with Orion, region D suffers a deficit of compact radio sources. The infrared nebulosities around two of the slightly resolved sources are suggested to be warm dust, and we argue that the associated radio sources trace free-free emission from ionized material. We confirm the thermal radio emission of the compact source in region E. However, its detection at infrared wavelengths implies that it is located in the foreground of the molecular cloud. Finally, three strongly variable sources are suggested to be magnetically active young stars.
3176. Compact radio sources in spiral galaxies. II.
ID:
ivo://CDS.VizieR/J/AJ/133/2559
Title:
Compact radio sources in spiral galaxies. II.
Short Name:
J/AJ/133/2559
Date:
21 Oct 2021
Publisher:
CDS
Description:
We report the analysis of deep radio observations of the interacting galaxy system M51 from the Very Large Array, with the goal of understanding the nature of the population of compact radio sources in nearby spiral galaxies. We detect 107 compact radio sources, 64% of which have optical counterparts in a deep H{alpha} Hubble Space Telescope image. Thirteen of the radio sources have X-ray counterparts from a Chandra observation of M51. We find that six of the associated H{alpha} sources are young supernova remnants (SNRs) with resolved shells. Most of the SNRs exhibit steep radio continuum spectral indices consistent with synchrotron emission. We detect emission from the Type Ic SN 1994I nearly a decade after explosion: the emission (160+/-22uJy/beam at 20cm, 46+/-11uJy/beam at 6cm, {alpha}=-1.02+/-0.28) is consistent with light-curve models for Type Ib/Ic supernovae. We detect X-ray emission from the supernova; however, no optical counterpart is present. We report on the analysis of the Seyfert 2 nucleus in this galaxy, including the evidence for bipolar outflows from the central black hole.
3177. Compact radio sources in the galactic plane
ID:
ivo://CDS.VizieR/J/AJ/130/586
Title:
Compact radio sources in the galactic plane
Short Name:
J/AJ/130/586
Date:
21 Oct 2021
Publisher:
CDS
Description:
Archival data have been combined with recent observations of the Galactic plane using the Very Large Array to create new catalogs of compact centimetric radio sources. The 20cm source catalog covers a longitude range of -20{deg}<l<120{deg} the latitude coverage varies from +/-0.8{deg} to +/-2.7{deg}. The total survey area is about 331{deg}^2^; coverage is 90% complete at a flux density threshold of about 14mJy, and over 5000 sources are recorded. The 6cm catalog covers 43{deg}^2^ in the region -10{deg}<l<42{deg}, |b|<0.4{deg} to a 90% completeness threshold of 2.9mJy; over 2700 sources are found. Both surveys have an angular resolution of about 6". These catalogs provide a 30% (at 20cm) to 50% (at 6cm) increase in the number of high-reliability compact sources in the Galactic plane, as well as greatly improved astrometry, uniformity, and reliability; they should prove useful for comparison with new mid- and far-infrared surveys of the Milky Way.
3178. Compact radio sources near Galactic center
ID:
ivo://CDS.VizieR/J/AZh/91/503
Title:
Compact radio sources near Galactic center
Short Name:
J/AZh/91/503
Date:
21 Oct 2021
Publisher:
CDS
Description:
Using literature data on approximately 400 compact radio sources detected with the Very Large Array and located in the direction of the Galactic center within 2{deg} of the compact source Sgr A*, 69 sources whose angular sizes are determined by scattering on electron density inhomogeneities were distinguished. Fifty-five of these are extragalactic, two are supercompact HII regions, ten are sources of maser emission, and two are variable Galactic sources. The excess of the apparent angular sizes of maser sources within 2{deg} of the Galactic center above the mean size of objects of this class in other parts of the Galaxy found in many studies cannot be explained purely by the effect of scattering of their radio emission on interstellar plasma inhomogeneities. The angular sizes of these objects are increased due to scattering only within Galactic longitudes of about 0.4{deg} and Galactic latitudes less than 0.1{deg}. The turbulent medium responsible for scattering of radio emission of compact sources in the immediate vicinity of the Galactic center is strongly concentrated toward the compact source Sgr A* at the Galactic center. No extragalactic sources are observed within 0.4{deg} in longitude and 0.2{deg} in latitude of the Galactic center, because of their low brightness due to the superstrong scattering in this region. Data on scatter broadening can be used to study the distribution of turbulent plasma near the Galactic center.
3179. Compact radio sources near the Galactic center
ID:
ivo://CDS.VizieR/J/ApJ/773/67
Title:
Compact radio sources near the Galactic center
Short Name:
J/ApJ/773/67
Date:
21 Oct 2021
Publisher:
CDS
Description:
We have observed the Galactic center (GC) region at 0.154 and 0.255GHz with the Giant Metrewave Radio Telescope. A total of 62 compact likely extragalactic (EG) sources are detected. Their scattering sizes decrease linearly with increasing angular distance from the GC up to about 1{deg}. The apparent scattering sizes of the sources are more than an order of magnitude less than predicted earlier by the NE2001 model of Galactic electron distribution within 359.5{deg}<l<0.5{deg} and -0.5{deg}<b<0.5{deg} (Hyperstrong Scattering Region) of the Galaxy. High free-free optical depths ({tau}) are observed toward most of the extended non-thermal sources within 0.6{deg} from the GC. Significant variation of {tau} indicates that the absorbing medium is patchy at an angular scale of ~10' and n_e_ is ~10/cm3, which matches the NE2001 model. This model predicts the EG sources to be resolved out from 1.4GHz interferometric surveys. However, out of 10 EG sources expected in the region, 8 likely EG are present in the 1.4GHz catalog. Ionized interfaces of dense molecular clouds to the ambient medium are most likely responsible for strong scattering and low radio frequency absorption. However, dense GC clouds traced by CS J=1-0 emission are found to have a narrow distribution of ~0.2{deg} across the Galactic plane. Angular distribution of most EG sources seen through the so-called Hyperstrong Scattering Region are random in b, and typically ~7 out of 10 sources will not be seen through the dense molecular clouds, which explains why most of them are not scatter broadened at 1.4GHz.
3180. Compact Radio Sources Near the Galactic Plane
ID:
ivo://CDS.VizieR/J/ApJS/80/211
Title:
Compact Radio Sources Near the Galactic Plane
Short Name:
J/ApJS/80/211
Date:
21 Oct 2021
Publisher:
CDS
Description:
The results of the extension of the 20-cm Galactic-plane survey reported by Zoonematkermani to Galactic latitudes of +/-1.8{deg} over the central region of the Milky Way are reported. A total of 1457 discrete radio sources down to flux densities of less than about 5mJy, and 95% completion is achieved at 20mJy. A detailed comparison of all radio sources from the survey in this longitude range with the IRAS Point Source Catalog provides classification for 13% of the objects, including 159 compact H II regions, and nearly 100 planetary nebulae, over 70 of which are identified. The identity of the remaining radio sources is discussed.

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