- ID:
- ivo://CDS.VizieR/J/A+AS/41/421
- Title:
- 1.4GHz survey in the Virgo region
- Short Name:
- J/A+AS/41/421
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- Radio continuum observations made with the Westerbork Synthesis Radio Telescope at 1.4GHz are presented for 274 galaxies in the Virgo Cluster region. The observations are partly full syntheses and partly east-west strip distributions. For the 55 detected galaxies the emission is separated into central and extended components. A brief summary of the analysis is also given.
Number of results to display per page
Search Results
- ID:
- ivo://CDS.VizieR/J/ApJ/704/1433
- Title:
- 31GHz survey of low-frequency radio sources
- Short Name:
- J/ApJ/704/1433
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- The 100m Robert C. Byrd Green Bank Telescope and the 40m Owens Valley Radio Observatory telescope have been used to conduct a 31GHz survey of 3165 known extragalactic radio sources over 143deg^2^ of the sky. Target sources were selected from the NRAO VLA Sky Survey in fields observed by the Cosmic Background Imager (CBI); most are extragalactic active galactic nuclei (AGNs) with 1.4GHz flux densities of 3-10mJy. The resulting 31GHz catalogs are presented in full online. Using a maximum-likelihood analysis to obtain an unbiased estimate of the distribution of the 1.4-31GHz spectral indices of these sources, we find a mean 31-1.4GHz flux ratio of 0.110+/-0.003 corresponding to a spectral index of {alpha}=-0.71+/-0.01 (S_{nu}_{prop.to}{nu}^{alpha}^); 9.0%+/-0.8% of sources have {alpha}>-0.5 and 1.2%+/-0.2% have {alpha}>0. By combining this spectral-index distribution with 1.4GHz source counts, we predict 31GHz source counts in the range 1mJy<S_31_<4mJy, N(>S_31_)=(16.7+/-1.7)deg^-2^(S_31_/1mJy)^-0.80+/-0.07^.
- ID:
- ivo://CDS.VizieR/J/ApJ/874/64
- Title:
- 5GHz TMRT observations of 71 pulsars
- Short Name:
- J/ApJ/874/64
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present integrated pulse profiles at 5GHz for 71 pulsars, including eight millisecond pulsars (MSPs), obtained using the Shanghai Tian Ma Radio Telescope. Mean flux densities and pulse widths are measured. For 19 normal pulsars and one MSP, these are the first detections at 5GHz --and for a further 19, including five MPSs, the profiles have a better signal-to-noise ratio than previous observations. Mean flux density spectra between 400MHz and 9GHz are presented for 27 pulsars and correlations of power-law spectral index are found with characteristic age, radio pseudo-luminosity, and spin-down luminosity. Mode changing was detected in five pulsars. The separation between the main pulse and interpulse is shown to be frequency independent for six pulsars, but a frequency dependence of the relative intensity of the main pulse and interpulse is found. The frequency dependence of component separations is investigated for 20 pulsars, and three groups are found: in seven cases, the separation between the outmost leading and trailing components decreases with frequency, roughly in agreement with radius-to-frequency mapping; in 11 cases, the separation is nearly constant; in the remaining two cases, the separation between the outmost components increases with frequency. We obtain the correlations of pulse widths with pulsar period and estimate the core widths of 23 multicomponent profiles and conal widths of 17 multicomponent profiles at 5GHz using Gaussian fitting, and we discuss the width-period relationship at 5GHz compared with the results at at 1.0 and 8.6GHz.
- ID:
- ivo://CDS.VizieR/J/MNRAS/502/4779
- Title:
- 28-40GHz variability and polarimetry
- Short Name:
- J/MNRAS/502/4779
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We observed 51 sources in the Q-U-I JOint TEnerife (QUIJOTE) cosmological fields which were brighter than 1Jy at 30GHz in the Planck Point Source Catalogue (version 1), with the Very Large Array at 28-40GHz, in order to characterise their high-radio-frequency variability and polarization properties. We find a roughly log-normal distribution of polarization fractions with a median of 2%, in agreement with previous studies, and a median rotation measure (RM) of ~1110rad/m^2^ with one outlier up to ~64000rad/m^2^ which is among the highest RMs measured in quasar cores. We find hints of a correlation between the total intensity flux density and median polarization fraction. We find 59% of sources are variable in total intensity, and 100% in polarization at 3{sigma} level, with no apparent correlation between total intensity variability and polarization variability. This indicates that it will be difficult to model these sources without simultaneous polarimetric monitoring observations and they will need to be masked for cosmological analysis.
- ID:
- ivo://CDS.VizieR/J/MNRAS/438/3058
- Title:
- 15GHz variability of {gamma}-ray blazars
- Short Name:
- J/MNRAS/438/3058
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present results from four years of twice-weekly 15GHz radio monitoring of about 1500 blazars with the Owens Valley Radio Observatory 40m telescope. Using the intrinsic modulation index to measure variability amplitude, we find that, with >6{sigma} significance, the radio variability of radio-selected {gamma}-ray-loud blazars is stronger than that of {gamma}-ray-quiet blazars. Our extended data set also includes at least 21 months of data for all AGN with 'clean' associations in the Fermi Large Area Telescope First AGN Catalog, 1LAC. With these additional data, we examine the radio variability properties of a {gamma}-ray-selected blazar sample. Within this sample, we find no evidence for a connection between radio variability amplitude and optical classification. In contrast, for our radio-selected sample we find that the BL Lac object subpopulation is more variable than the flat-spectrum radio quasar (FSRQ) subpopulation. Radio variability is found to correlate with the synchrotron peak frequency, with low- and intermediate-synchrotron-peaked blazars varying more than high-synchrotron-peaked ones. We find evidence for a significant negative correlation between redshift and radio variability among bright FSRQs.
- ID:
- ivo://CDS.VizieR/J/A+A/364/391
- Title:
- 86GHz VLBI survey of compact radio sources
- Short Name:
- J/A+A/364/391
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- File table1 contains the list of observed sources, providing the source coordinates (J2000) and redshift, detection status, type, optical magnitude, and brightness temperature of the radio emission. File table4 contains the description of the VLBI data, and provide the observed total and correlated flux densities, the parameters of single gaussian component model fits, and the parameters of hybrid images of the observed sources. File table5 contains multicomponent model fits for the sources with detected extended structures and the brightness temperatures derived from these model fits.
- ID:
- ivo://CDS.VizieR/J/A+A/546/A16
- Title:
- 22-GHz water maser clouds
- Short Name:
- J/A+A/546/A16
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- Cool, evolved stars undergo copious mass loss but the detailed mechanisms and the form in which the matter is returned the ISM are still under debate. We investigated the structure and evolution of the wind at 5 to 50 stellar radii from Asymptotic Giant Branch and Red Supergiant stars.
- ID:
- ivo://CDS.VizieR/J/AZh/62/229
- Title:
- Giant H II region Ratan-600 observations
- Short Name:
- J/AZh/62/229
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- The results of observations of a giant H II region, situated at the longitudes 4-10deg, at the wavelength 7.6cm are presented. A catalogue has been compiled containing 63 sources for which the positions, flux densities, and angular dimensions have been determined. Forty-four objects with the fluxes P<1Jy and having small angular sizes have been detected. The radio brightness distribution of the background component of the galactic radio emission has been obtained. A weak background extended by more than 2deg in the galactic latitude has been registered. It is shown that the detected weak objects represent a more high-latitude population than the strong galactic sources and are probably associated with the weak extended background.
- ID:
- ivo://CDS.VizieR/J/ApJS/149/343
- Title:
- Giant molecular clouds in M33
- Short Name:
- J/ApJS/149/343
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present the first interferometric ^12^CO (J=1->0) map of the entire H{alpha} disk of M33. The 13" diameter synthesized beam corresponds to a linear resolution of 50pc, sufficient to distinguish individual giant molecular clouds (GMCs). From these data we generated a catalog of 148 GMCs with an expectation that no more than 15 of the sources are spurious. The catalog is complete down to GMC masses of 1.5x10^5^M_{sun}_ and contains a total mass of 2.3x10^7^M_{sun}_.
- ID:
- ivo://CDS.VizieR/J/ApJ/654/240
- Title:
- Giant molecular clouds in M31
- Short Name:
- J/ApJ/654/240
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present Berkeley-Illinois-Maryland Association (BIMA) millimeter interferometer observations of giant molecular clouds (GMCs) along a spiral arm in M31. The observations consist of a survey using the compact configuration of the interferometer and follow-up, higher resolution observations on a subset of the detections in the survey. The data are processed using an analysis algorithm designed to extract GMCs and correct their derived properties for observational biases, thereby facilitating comparison with Milky Way data. The algorithm identifies 67 GMCs, of which 19 have a sufficient signal-to-noise ratio to accurately measure their properties. The GMCs in this portion of M31 are indistinguishable from those found in the Milky Way, having a similar size-line width relationship and distribution of virial parameters, confirming the results of previous, smaller studies. The velocity gradients and angular momenta of the GMCs are comparable to the values measured in M33 and the Milky Way, and in all cases are below expected values based on the local galactic shear. The studied region of M31 has an interstellar radiation field, metallicity, Toomre Q parameter, and midplane volume density similar to those of the inner Milky Way, so the similarity of GMC populations between the two systems is not surprising.