- ID:
- ivo://CDS.VizieR/J/other/Ser/183.103
- Title:
- SMC observations at 13, 20 and 36cm
- Short Name:
- J/other/Ser/183.
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present a new catalogue of radio-continuum sources in the field of the Small Magellanic Cloud (SMC). This catalogue contains sources previously not found in 2370MHz (λ=13cm) with sources found at 1400MHz (λ=20cm) and 843MHz (λ=36cm). 45 sources have been detected at 13cm, with 1560 sources at 20cm created from new high sensitivity and resolution radio-continuum images of the SMC at 20cm from paper I (Wong et al., <A HREF="http://simbad.cds.unistra.fr/simbad/sim-ref?bibcode=2011SerAJ.182...43W%202011SerAJ.182...43W">2011SerAJ.182...43W 2011SerAJ.182...43W</A>). We also created a 36cm catalogue to which we listed 1689 radio-continuum sources.
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Search Results
- ID:
- ivo://CDS.VizieR/J/MNRAS/431/2453
- Title:
- SN1996cr radio observations
- Short Name:
- J/MNRAS/431/2453
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present newly reduced archival radio observations of SN 1996cr in the Circinus Galaxy from the Australia Telescope Compact Array and the Molonglo Observatory Synthesis Telescope, and attempt to model its radio light curves using recent hydrodynamical simulations of the interaction between the supernova (SN) ejecta and the circumstellar material (CSM) at X-ray wavelengths. The radio data within the first 1000d show clear signs of free-free absorption (FFA), which decreases gradually and is minimal above 1.4GHz after day ~3000. Constraints on the FFA optical depth provide estimates of the CSM free electron density, which allows insight into the ionization of SN 1996cr's CSM and offers a test on the density distribution adopted by the hydrodynamical simulation. The intrinsic spectral index of the radiation shows evidence for spectral flattening, which is characterized by {alpha}=0.852+/-0.002 at day 3000 and a decay rate of {Delta}{alpha}=-0.014+/-0.001yr^-1^. The striking similarity in the spectral flattening of SN 1987A, SN 1993J and SN 1996cr suggests this may be a relatively common feature of SNe/CSM shocks. We adopt this spectral index variation to model the synchrotron radio emission of the shock, and consider several scalings that relate the parameters of the hydrodynamical simulation to the magnetic field and electron distribution. The simulated light curves match the large-scale features of the observed light curves, but fail to match certain tightly constraining sections. This suggests that simple energy density scalings may not be able to account for the complexities of the true physical processes at work, or alternatively, that the parameters of the simulation require modification in order to accurately represent the surroundings of SN 1996cr.
- ID:
- ivo://CDS.VizieR/J/A+A/593/A18
- Title:
- SN 2008iz 4.8 and 8.4GHz images
- Short Name:
- J/A+A/593/A18
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We report on multi-frequency Very Large Array (VLA) and Very Long Baseline Interferometry (VLBI) radio observations for a monitoring campaign of supernova SN 2008iz in the nearby irregular galaxy M82.
- ID:
- ivo://CDS.VizieR/J/A+A/587/A71
- Title:
- SNR G11.0-0.0 1.4GHz radio continuum image
- Short Name:
- J/A+A/587/A71
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- The main goal of this paper is to provide new insights on the origin of the observable flux of {gamma} rays from HESS J1809-193 using new high-quality observations in the radio domain. We used the Expanded Very Large Array (now known as the Karl G. Jansky Very large Array, JVLA) to produce a deep full-synthesis imaging at 1.4GHz of the vicinity of PSR J1809-1917. These data were used in conjunction with 12CO observations from the James Clerk Maxwell Telescope in the transition line J=3-2 and atomic hydrogen data from the Southern Galactic Plane Survey to investigate the properties of the interstellar medium in the direction of the source HESS J1809-193.
- ID:
- ivo://CDS.VizieR/J/A+A/642/A136
- Title:
- Sources detected at 325 and 610 MHz in Cygnus
- Short Name:
- J/A+A/642/A136
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- Observations at the radio continuum band below the gigahertz band are key when the nature and properties of non-thermal sources are investigated because their radio radiation is strongest at these frequencies. The low radio frequency range is therefore the best to spot possible counterparts to very high-energy (VHE) sources: relativistic particles of the same population are likely to be involved in radio and high-energy radiation processes. Some of these counterparts to VHE sources can be stellar sources. The Cygnus region in the northern sky is one of the richest in this type of sources that are potential counterparts to VHEsources. We surveyed the central ~15 sq deg of the Cygnus constellation at the 325 and 610MHz bands with angular resolutions and sensitivities of 10" and 6", and 0.5 and 0.2mJy/beam, respectively. The data were collected during 172 hours in 2013-2017, using the Giant Metrewave Radio Telescope (GMRT) with 32MHz bandwidth, and were calibrated using the SPAM routines. The source extraction was carried out with the PyBDSF tool,followed by verification through visual inspection of every putative catalog candidate source in order to determine its reliability. In this first paper we present the catalog of sources, consisting of 1048 sources at 325MHz and 2796 sources at 610MHz. By cross-matching the sources from both frequencies with the objects of the SIMBAD database, we found possible counterparts for 143 of them. Most of the sources from the 325MHz catalog (993) were detected at the 610MHz band, and their spectral index alpha was computed adopting S(nu){prop.to}nu^alpha^. The maximum of the spectral index distribution is at alpha=-1, which is characteristic of non-thermal emitters and might indicate an extragalactic population.
- ID:
- ivo://CDS.VizieR/J/AZh/85/483
- Title:
- Sources from the WMAP catalog
- Short Name:
- J/AZh/85/483
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- Observations of a complete sample of sources from the WMAP catalog were obtained at 22.2 and 36.8GHz on the RT-22 radio telescope of the Crimean Astrophysical Observatory. We have determined the distribution of the source spectral indices between these frequencies. The distributions of the spectral indices of the WMAP catalog (between 23 and 33GHz) and in the RT-22 sample have the same shape and half-width, suggesting that the mean source parameters are constant in time. We have plotted the logN-logS dependence down to the flux levels of about 0.1Jy using pilot data from the AT20 survey, where a cosmological "cutoff" in the source counts is already observed. The variability of individual sources in connection with flare activity is considered. The optical characteristics of the complete sample of WMAP sources are compared to those of identified AT20 survey sources.
- ID:
- ivo://CDS.VizieR/J/MNRAS/406/1853
- Title:
- Sources in VSA fields at 30GHz
- Short Name:
- J/MNRAS/406/1853
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- Small angular scale (high multipole order l) studies of cosmic microwave background (CMB) anisotropies require accurate knowledge of the statistical properties of extragalactic sources at cm-mm wavelengths. We have used a 30GHz dual-beam receiver (One Centimetre Receiver Array prototype) on the Torun 32-m telescope to measure the flux densities of 121 sources in Very Small Array fields selected at 15GHz with the Ryle Telescope. We have detected 57 sources above a limiting flux density of 5mJy, of which 31 sources have a flux density greater than 10mJy, which is our effective completeness limit. From these measurements we derive a surface density of sources above 10mJy at 30GHz of 2.2+/-0.4deg^-2^. This is consistent with the surface density obtained by Mason et al. who observed a large sample of sources selected at a much lower frequency (1.4GHz). We have also investigated the dependence of the spectral index distribution on flux density by comparing our results with those for sources above 1Jy selected from the Wilkinson Microwave Anisotropy Probe 22GHz catalogue.
- ID:
- ivo://CDS.VizieR/J/ApJ/897/5
- Title:
- 90 sources radio flux density from GLEAM and HERA
- Short Name:
- J/ApJ/897/5
- Date:
- 16 Mar 2022 00:49:20
- Publisher:
- CDS
- Description:
- The central challenge in 21cm cosmology is isolating the cosmological signal from bright foregrounds. Many separation techniques rely on the accurate knowledge of the sky and the instrumental response, including the antenna primary beam. For drift-scan telescopes, such as the Hydrogen Epoch of Reionization Array (HERA), that do not move, primary beam characterization is particularly challenging because standard beam-calibration routines do not apply (Cornwell et al.) and current techniques require accurate source catalogs at the telescope resolution. We present an extension of the method from Pober et al. where they use beam symmetries to create a network of overlapping source tracks that break the degeneracy between source flux density and beam response and allow their simultaneous estimation. We fit the beam response of our instrument using early HERA observations and find that our results agree well with electromagnetic simulations down to a -20dB level in power relative to peak gain for sources with high signal-to-noise ratio. In addition, we construct a source catalog with 90 sources down to a flux density of 1.4Jy at 151MHz.
- ID:
- ivo://CDS.VizieR/J/ApJS/80/137
- Title:
- Southern Extragalactic Radio Sources
- Short Name:
- J/ApJS/80/137
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- This catalog contains a list of 384 extragalactic radio sources south of declination -30{deg} which have been imaged with the Molonglo Observatory Synthesis Telescope (MOST) at 843 MHz with a HPBW of 44" x 44" cosec(dec). The sample includes those sources noted in the Molonglo Reference Catalog (MRC) (Cat.<VIII/16>) as extended (larger than 1'), as well as those noted as multiple (within 8' of another ssource and possibly related). The sample is representative of the strong extended extragalactic radio sources of the southern sky, but is not statistically complete. Positions, flux densities, and sizes are given for all sources, and those sources which have been confirmed as extended MRC sources are flagged. In addition, optical positions, magnitudes, redshifts, and identifications are given for 201 of the sources. These data were originally published in two tables which have been merged in this version.
- ID:
- ivo://CDS.VizieR/VIII/45
- Title:
- Southern flat-spectrum sources
- Short Name:
- VIII/45
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- Optical identifications have been sought for 198 southern radio sources (73 in Paper I, 06h<RA(B1950)<18h and 125 in Paper II, 18h<RA(B1950)<06h) using new positions determined with the six-dish array of the Fleurs synthesis telescope. These sources constitute a complete sample drawn from the Parkes 2700-MHz catalogue. They are all flat-spectrum sources stronger than 0.25 Jy at 2700 MHz and lie between Dec(B1950) -80 and -50{deg}. Sources with |b|<5{deg} are not included. The new radio positions have standard deviations of about 1'' (2'' in Paper I, 1'' in Paper II) in right ascension and declination. The optical positions are with respect to the FK4 reference system as defined by the Perth catalogues and have position uncertainties of about 0.5arcsec. Magnitude estimates are on the J scale and are accurate to about 0.4mag for stellar-like objects and 0.5 to 1.0mag for galaxies. The sample is complete to the 22.5-mag limit of the SERC-J sky atlas. There are 198 sources in the complete sample. 31 sources (16%) show some radio structure with the 2'' beam. For the 175 unresolved sources, there are 124 QSOs (71%), 26 galaxies (15%) and 25 empty fields (14%) suggested.
