At the faintest radio flux densities (S1.4<10mJy), conflicting results have arisen regarding whether there is a flattening of the average spectral index between a low radio frequency (325 or 610MHz) and, for example, 1.4GHz. We present a new catalogue of 843-MHz radio sources in the European Large Area ISO Survey-South 1 field, which contains the sources, their Australia Telescope Large Area Survey (ATLAS) counterparts and the spectral index distribution of the sources as a function of flux density.
The Murchison Widefield Array Commissioning Survey (MWACS) is a ~6100deg^2^ 104-196MHz radio sky survey performed with the Murchison Widefield Array during instrument commissioning between 2012 September and 2012 December. The data were taken as meridian drift scans with two different 32-antenna sub-arrays that were available during the commissioning period. The data were combined in the visibility plane before being imaged, and then mosaicked. The survey covers approximately 20.5h<RA<8.5h, -58{deg}<Dec<-14{deg} over three frequency bands centred on 119, 150 and 180MHz. The survey has 3arcmin angular resolution and a typical noise level of 40mJy/beam, with reduced sensitivity near the field boundaries and bright sources. The catalogue consists of flux density and spectral index measurements for 14,110 sources, extracted from the mosaics, 1,247 of which are sub-components of complexes of sources.
We present the measurements of scatter broadening timescales ({tau}_SC_) for 124 pulsars at 327MHz using the upgraded Ooty Radio Telescope (ORT). These pulsars lie in the dispersion measure range of 37-503pc/cm3 and declination ({delta}) range of -57{deg}<{sigma}<60{deg}. New {tau}_SC_ estimates for 58 pulsars are presented, increasing the sample of all such measurements by about 40% at 327MHz. Using all available {tau}_SC_ measurements in the literature, we investigate the dependence of {tau}_SC_ on dispersion measure. Our measurements, together with previously reported values for {tau}_SC_, affirm that the ionized interstellar medium up to 3kpc is consistent with the Kolmogorov spectrum, while it deviates significantly beyond this distance.
Observations of the Spitzer extragalactic First Look Survey field taken at 610MHz with the Giant Metre-wave Radio Telescope are presented. Seven individual pointings were observed, covering a total area of 4 square degrees with a resolution of 5.8x4.7arcsec^2^, PA=60{deg}. The r.m.s. noise at the centre of the pointings is between 27 and 30uJy before correction for the GMRT primary beam. The techniques used for data reduction and production of a mosaicked image of the region are described, and the final mosaic, along with a catalogue of 3944 sources detected above ~5{sigma} are presented. The survey complements existing radio and infrared data available for this region. For further details of the surveys and data analysis procedures please refer to the published paper.
Observations with MERLIN at 408 MHz have been used to establish the low-frequency part of the spectra of more than a hundred compact radio sources taken from the part of the Jodrell Bank-VLA Astrometric Survey (JVAS) limited by 35{deg}<={delta}<=75{deg}. These sources were selected from JVAS and other catalogues to have convex spectra between 1.4 and 8.4GHz, characteristic of Gigahertz Peaked Spectrum sources. We have confirmed convex shapes of the spectra of 76 objects.
2703 sources have been observed at the 1612MHz transition of OH, and 783 OH/IR stars were detected; 597 of these detections are new discoveries. The IRAS sources were detected on the basis of their IRAS fluxes at 12, 25 and 60um. The survey is 70% complete for IRAS sources in the Southern hemisphere (Dec<-10{deg}) with F(12um)>3Jy, with IR colors log(F25/F12)>-0.2 and log(F60/F12)<0.6 Note that the file catalog.dat contains all observed sources, with a flag indicating the detection or non-detection; the detected sources only are listed in the printed version of Table2, while sources without detectable 1612MHz emission are listed in Table3 (on microfiche)
1420MHz radio continuum survey of the southern sky
Short Name:
J/A+A/376/861
Date:
21 Oct 2021
Publisher:
CDS
Description:
The results of an absolutely calibrated radio continuum survey of the South Celestial Hemisphere at a frequency of 1420MHz are presented. Contour maps show the area 0h<=RA<=24h for the declination range -90{deg} to -10{deg}. Contour steps (50mK T_B_; 3xrms noise) and angular resolution (HPBW 35.4') of the maps match the already existing Stockert telescope Northern Sky Survey at the same frequency (Reich 1982A&AS...48..219R ; Reich & Reich 1986A&AS...63..205R). We compare flux densities of compact and extended sources with published data from the Parkes 64-m telescope and find excellent agreement in general. The survey maps are sensitive enough to constrain synchrotron and thermal emission components which might influence studies of the cosmic microwave background.
An analysis of 125 radio sources from a 102MHz survey of scintillating sources is presented. These compact (<1") radio sources are identified with radio sources in the most sensitive catalogs currently available. Analysis of the integrated spectra for these objects indicates that the compact sources have steep spectra ({alpha}>0.5). There is a tendency for weaker sources to be more compact. The inferred spectral indices for compact sources in the cores of extended objects are on average lower than the integrated values. The most likely candidates for optical counterparts to the compact radio sources from the scintillating source survey are steep-spectrum quasars.
We present here the results of a 325MHz radio survey of M31, conducted with the A configuration of the Very Large Array. The survey covered an area of 7.6{deg}^2^, and a total of 405 radio sources between <~6" and 170" in extent were mapped with a resolution of 6" and a 1{sigma} sensitivity of ~0.6mJy/beam. For each source, its morphological class, major axis {theta}_M_, minor axis {theta}_m_, position angle {theta}_PA_, peak flux I, integrated flux density S, spectral index {alpha}, and spectral curvature parameter {phi} were calculated.
We have previously presented the results of a 325MHz radio survey of M31 (Cat. <J/ApJS/155/89>, conducted with the A configuration of the Very Large Array. In this survey, a total of 405 radio sources between <~6" and 170" in extent were mapped with a resolution of 6" and a sensitivity of ~0.6mJy/beam. Here we compare the resultant source list and image with other radio, IR, optical, and X-ray observations and catalogs of the region.
