- ID:
- ivo://CDS.VizieR/J/ApJS/93/145
- Title:
- Radio survey around North Ecliptic Pole
- Short Name:
- J/ApJS/93/145
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- A 29.3deg^2 region surrounding the north ecliptic pole (NEP; R.A.=18h00m, Dec.=+66d30m) was mapped with the Very Large Array at 1.5GHz to support the deepest portion of the ROSAT all-sky soft X-ray survey. The resulting VLA-NEP survey catalog contains 2435 radio sources with flux densities in the range of 0.3-1000mJy, including over 200 fainter than 1mJy. The 28 fields of the inner 1.5deg have noise levels sigma ~=60uJy, and the 85 fields centered between 1.5deg and 3.0deg from the NEP have sigma ~=120uJy. The typical spatial resolution is 20" HPBW, and most positions are accurate to <2". Approximately 6% of the sources are found to be extended with size >30". We have compared the VLA-NEP catalog with four other radio catalogs made at lower resolution, as well as with the NASA Extragalactic Database and find counterparts for ~18% of the VLA-NEP objects. The normalized, differential radio source count is in agreement with the previous studies. Between 1 and 150mJy the slope of the logN-logS relation is 0.68+/-0.03.
Number of results to display per page
Search Results
- ID:
- ivo://CDS.VizieR/VIII/43
- Title:
- Radio survey of clusters of galaxies
- Short Name:
- VIII/43
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- Observations of Abell clusters at 11.1, 6.2, 6.3 and 2.8cm with the 100m Effelsberg telescope. The data were compiled by H.J. Andernach.
- ID:
- ivo://CDS.VizieR/J/MNRAS/378/995
- Title:
- Radio survey of the 1H XMM/Chandra field
- Short Name:
- J/MNRAS/378/995
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present the results of a deep 610-MHz survey of the 1^H^ XMM-Newton/Chandra survey area with the Giant Metre-wave Radio Telescope. The resulting maps have a resolution of ~7arcsec and an rms noise limit of 60Jy. To a 5{sigma} detection limit of 300Jy, we detect 223 sources within a survey area of 64arcmin in diameter. We compute the 610-MHz source counts and compare them to those measured at other radio wavelengths.
- ID:
- ivo://CDS.VizieR/J/A+A/549/A131
- Title:
- Radio survey of ultracool dwarfs
- Short Name:
- J/A+A/549/A131
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We aim to increase the sample of ultracool dwarfs studied in the radio domain to allow a more statistically significant understanding of the physical conditions associated with these magnetically active objects. We conducted a volume-limited survey at 4.9GHz of 32 nearby ultracool dwarfs with spectral types covering the range M7-T8. A statistical analysis was performed on the combined data from the present survey and previous radio observations of ultracool dwarfs.
- ID:
- ivo://CDS.VizieR/J/MNRAS/391/297
- Title:
- Radio Survey of 7 X-ray Clusters of Galaxies
- Short Name:
- J/MNRAS/391/297
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- The Australia Telescope Compact Array (ATCA) has been used at 1.38 and 2.38GHz to survey seven southern Abell clusters of galaxies with high X-ray luminosities: A2746, A2837, A3126, A3216, A3230, A3827 and A3836. The clusters have also been surveyed at 0.843GHz with the Molonglo Observatory Synthesis Telescope (MOST). We have listed a complete 1.38-GHz sample of 149 radio sources within the Abell circles centred on their X-ray centroids. We compare their identification fractions, emitted 1.38-GHz and optical powers, radio spectral indices and radial variation in projected source density with those of the radio-selected samples of Slee et al. (1998AuJPh..51..971S). We compare our fractional radio luminosity function with that of the radio-selected samples of Ledlow and Owen (1996AJ....112....9L) and Slee et al. (1998AuJPh..51..971S). Three significant differences are noted between X-ray and radio-selected samples of clusters; (1) the X-ray sample has an excess of flat-spectrum radio sources; (2) the fractional radio luminosity function for the FR I sources in the X-ray selected sample is much steeper, implying that fewer of their cluster galaxies become hosts for the stronger FR I radio galaxies; (3) a complete absence of FR II radio galaxies in the X-ray selected sample. The average excess projected density of radio sources near our cluster centres is approx. 5 times the background source density.
- ID:
- ivo://CDS.VizieR/J/MNRAS/298/692
- Title:
- Radio Survey of X-ray sources
- Short Name:
- J/MNRAS/298/692
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present a radio survey of X-ray sources in the Large and Small Magellanic clouds with the Australia Telescope Compact Array at 6.3 and 3.5 cm. Specifically, we have observed the fields of five LMC and two SMC supersoft X-ray sources, the X-ray binaries LMC X-1, X-2, X-3 & X-4, the X-ray transient Nova SMC 1992, and the soft gamma-ray repeater SGR 0525-66. None of the targets are detected as point sources at their catalogued positions. In particular, the proposed supersoft jet source RXJ 0513-69 is not detected, placing constraints on its radio luminosity compared to Galactic jet sources. Limits on emission from the black hole candidate systems LMC X-1 and X-3 are consistent with the radio behaviour of persistent Galactic black hole X-ray binaries, and a previous possible radio detection of LMC X-1 is found to almost certainly be due to nearby field sources. The SNR N49 in the field of SGR 0525-66 is mapped at higher resolution than previously, but there is still no evidence for any enhanced emission or disruption of the SNR at the location of the X-ray source. No radio point sources were detected at any wavelength at the catalogued locations of the target sources. In most cases a noise level of 50 microJy or so was achieved, making the 3-sigma upper limits very stringent indeed. The noise levels for LMC X-1 and SGR 0525-66 are considerably worse, due to their locations in radio-bright regions.
- ID:
- ivo://CDS.VizieR/J/ApJ/510/64
- Title:
- Radio time delay of gravitational lens 0957+561
- Short Name:
- J/ApJ/510/64
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- The gravitational lens 0957+561 was monitored with the Very Large Array from 1979 to 1997. The 6 cm light-curve data from 1995 to 1997 and the 4cm data from 1990 to 1997 are reported here. At 4cm the intrinsic source variations occur earlier and are twice as large as the corresponding variations at 6cm. The VLBI core and jet components have different magnification factors, leading to different flux ratios for the varying and nonvarying portions of the VLA light curves. Using both the Press, Rybicki, & Hewitt Q (1992ApJ...385..404P) and dispersion statistical techniques, we determined the time delay, core flux ratio, and excess nonvarying B image flux density. The fits were performed for the 4 and 6 cm light curves, both individually and jointly, and we used Gaussian Monte Carlo data to estimate 68% statistical confidence levels. The delay estimates from each individual wavelength were inconsistent given the formal uncertainties, suggesting that there are unmodeled systematic errors in the analysis. We roughly estimate the systematic uncertainty in the joint result from the difference between the 6 and 4cm results, giving 409+/-30 days for the PRHQ statistic and 397+/-20 days for the dispersion statistic. These results are consistent with the current optical time delay of 417+/-3 days, reconciling the long-standing difference between the optical and radio light curves and between different statistical analyses.
- ID:
- ivo://CDS.VizieR/J/ApJ/884/121
- Title:
- Radio to UV observations of GRB 181201A
- Short Name:
- J/ApJ/884/121
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present comprehensive multiwavelength radio to X-ray observations of GRB 181201A spanning from ~150s to ~163days after the burst, comprising the first joint ALMA-VLA-GMRT observations of a gamma-ray burst (GRB) afterglow. The radio and millimeter-band data reveal a distinct signature at ~3.9days, which we interpret as reverse-shock (RS) emission. Our observations present the first time that a single radio- frequency spectral energy distribution can be decomposed directly into RS and forward shock (FS) components. We perform detailed modeling of the full multiwavelength data set, using Markov Chain Monte Carlo sampling to construct the joint posterior density function of the underlying physical parameters describing the RS and FS synchrotron emission. We uncover and account for all discovered degeneracies in the model parameters. The joint RS-FS modeling reveals a weakly magnetized ({sigma}~3x10^-3^), mildly relativistic RS, from which we derive an initial bulk Lorentz factor of {Gamma}_0_~103 for the GRB jet. Our results support the hypothesis that low-density environments are conducive to the observability of RS emission. We compare our observations to other events with strong RS detections and find a likely observational bias selecting for longer lasting, nonrelativistic RSs. We present and begin to address new challenges in modeling posed by the present generation of comprehensive, multifrequency data sets.
- ID:
- ivo://CDS.VizieR/J/A+AS/109/267
- Title:
- Radio to X-Ray distribution of BL Lac Objects
- Short Name:
- J/A+AS/109/267
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- (no description available)
- ID:
- ivo://CDS.VizieR/J/ApJ/704/652
- Title:
- Radio transients in a 1.4GHz drift-scan survey
- Short Name:
- J/ApJ/704/652
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We report two new radio transients at high Galactic latitude, WJN J0951+3300 (RA=09h51m22s+/-10s, DE=33{deg}00'+/-0.4{deg}, b=50{deg}54.2') and WJN J1039+3300 (RA=10h39m26s+/-10s, DE=33{deg}00'+/-0.4{deg}, b=60{deg}58.5'), which were detected by interferometric drift-scan observations at 1.4GHz at the Waseda Nasu Pulsar Observatory. WJN J0951+3300 was detected at 16:49:32UT on 2006 January 12 with the flux density of approximately 1760.5+/-265.9mJy, and WJN J1039+3300 was detected at 17:13:32UT on 2006 January 18 with the flux density of approximately 2242.5+/-228.7mJy. Both of them lasted for a short duration (<=2 days). The possibility that the distribution of the WJN radio transients is isotropic was suggested in a previous study. Having re-evaluated the log N-log S relation with the addition of the two new objects reported in this paper, we find that the slope is consistent with a slope of -1.5 and the previous result. Additionally, although there are several counterparts to WJN radio transients, we found that one of the quasar counterparts within the positional error of WJN J0951+3300 could be a radio-loud quasar. We have discussed whether or not WJN J0951+3300 could be of this quasar origin.
