- ID:
- ivo://CDS.VizieR/J/ApJ/725/1792
- Title:
- Pi Ghz Sky Survey (PiGSS). I.
- Short Name:
- J/ApJ/725/1792
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- The Pi GHz Sky Survey (PiGSS) is a key project of the Allen Telescope Array. PiGSS is a 3.1GHz survey of radio continuum emission in the extragalactic sky with an emphasis on synoptic observations that measure the static and time-variable properties of the sky. During the 2.5 year campaign, PiGSS will twice observe ~250000 radio sources in the 10000deg^2^ region of the sky with b>30{deg} to an rms sensitivity of ~1mJy. Additionally, sub-regions of the sky will be observed multiple times to characterize variability on timescales of days to years. We present here observations of a 10deg^2^ region in the Bootes constellation overlapping the NOAO Deep Wide Field Survey field. The PiGSS image was constructed from 75 daily observations distributed over a 4 month period and has an rms flux density between 200 and 250uJy. This represents a deeper image by a factor of 4-8 than we will achieve over the entire 10000deg^2^. We provide flux densities, source sizes, and spectral indices for the 425 sources detected in the image. We identify ~100 new flat-spectrum radio sources; we project that when completed PiGSS will identify 104 flat-spectrum sources. We identify one source that is a possible transient radio source. This survey provides new limits on faint radio transients and variables with characteristic durations of months.
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- ID:
- ivo://CDS.VizieR/J/ApJ/739/76
- Title:
- Pi GHz Sky Survey (PiGSS). II.
- Short Name:
- J/ApJ/739/76
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present results from daily radio continuum observations of the Bootes field as part of the Pi GHz Sky Survey (PiGSS). These results are part of a systematic and unbiased campaign to characterize variable and transient sources in the radio sky. The observations include 78 individual epochs distributed over five months at a radio frequency of 3.1GHz with a median rms image noise in each epoch of 2.8mJy. We produce five monthly images with a median rms of 0.6mJy. No transient radio sources are detected in the daily or monthly images. At 15mJy, we set an upper limit (2{sigma}) to the surface density of one-day radio transients at 0.025deg^-2^. At 5mJy, we set an upper limit (2{sigma}) to the surface density of one-month radio transients at 0.18deg^-2^. We also produce light curves for 425 sources and explore the variability properties of these sources. Approximately 20% of the sources exhibit some variability on daily and monthly timescales. The maximum rms fractional modulations on the one-day and one-month timescales for sources brighter than 10mJy are 2 and 0.5, respectively. The probability of a daily fluctuation for all sources and all epochs by a factor of 10 is less than 10^-4^. We compare the radio to mid-infrared variability for sources in the field and find no correlation. Finally, we apply the statistics of transient and variable populations to constrain models for a variety of source classes.
- ID:
- ivo://CDS.VizieR/J/ApJ/762/93
- Title:
- PiGSS. III. ELAIS-N1, Coma & Lockman fields
- Short Name:
- J/ApJ/762/93
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present results from a total of 459 repeated 3.1GHz radio continuum observations (of which 379 were used in a search for transient sources) of the ELAIS-N1, Coma, Lockman Hole, and NOAO Deep Wide Field Survey fields as part of the Pi GHz Sky Survey. The observations were taken approximately once per day between 2009 May and 2011 April. Each image covers 11.8 square degrees and has 100" FWHM resolution. Deep images for each of the four fields have rms noise between 180 and 310{mu}Jy, and the corresponding catalogs contain ~200 sources in each field. Typically 40-50 of these sources are detected in each single-epoch image. This represents one of the shortest cadence, largest area, multi-epoch surveys undertaken at these frequencies. We compare the catalogs generated from the combined images to those from individual epochs, and from monthly averages, as well as to legacy surveys. We undertake a search for transients, with particular emphasis on excluding false positive sources. We find no confirmed transients, defined here as sources that can be shown to have varied by at least a factor of 10. However, we find one source that brightened in a single-epoch image to at least six times the upper limit from the corresponding deep image. We also find a source associated with a z=0.6 quasar which appears to have brightened by a factor ~3 in one of our deep images, when compared to catalogs from legacy surveys. We place new upper limits on the number of transients brighter than 10mJy: fewer than 0.08 transients deg^-2^ with characteristic timescales of months to years; fewer than 0.02deg^-2^ with timescales of months; and fewer than 0.009deg^-2^ with timescales of days. We also plot upper limits as a function of flux density for transients on the same timescales.
- ID:
- ivo://CDS.VizieR/J/MNRAS/458/3619
- Title:
- Planck ERCSC sources with 100 GHz flux excess
- Short Name:
- J/MNRAS/458/3619
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- The Planck Early Release Compact Source Catalogue (ERCSC) includes nine lists of highly reliable sources, individually extracted at each of the nine Planck frequency channels. To facilitate the study of the Planck sources, especially their spectral behaviour across the radio/infrared frequencies, we provide a 'bandmerged' catalogue of the ERCSC sources. This catalogue consists of 15191 entries, with 79 sources detected in all nine frequency channels of Planck and 6818 sources detected in only one channel. We describe the bandmerging algorithm, including the various steps used to disentangle sources in confused regions. The multifrequency matching allows us to develop spectral energy distributions of sources between 30 and 857GHz, in particular across the 100GHz band, where the energetically important CO J=1->0 line enters the Planck bandpass. We find ~3{sigma}-5{sigma} evidence for contribution to the 100GHz intensity from foreground CO along the line of sight to 147 sources with |b|>{30deg}. The median excess contribution is 4.5+/-0.9 per cent of their measured 100 GHz flux density which cannot be explained by calibration or beam uncertainties. This translates to 0.5+/-0.1K.km/s of CO which must be clumped on the scale of the Planck 100GHz beam, i.e. ~10-arcmin. If this is due to a population of low-mass (~15M_{sun}_) molecular gas clumps, the total mass in these clumps may be more than 2000 M_{sun}_. Further, high-spatial-resolution, ground-based observations of the high-latitude sky will help shed light on the origin of this diffuse, clumpy CO emission.
- ID:
- ivo://CDS.VizieR/J/other/AstBu/76.109
- Title:
- Planck maps spots near RCR sources
- Short Name:
- J/other/AstBu/76
- Date:
- 22 Feb 2022
- Publisher:
- CDS
- Description:
- The spectral properties of the inhomogeneities of the microwave background on Planck multi-frequency maps that are distant from the sources of the RCR catalog by the half-width of the power beam pattern of the high-frequency Planck complex (+/-2.5 arcmin), as well as the spectral features of the sources depending on the presence of positive spots near them, are studied. About 830 objects of the catalog were examined for the detection of spots with positive amplitudes near them. The features that indicate the connection of positive peaks on the Planck maps with the nearest radio sources are revealed. First, it is the excess of the number of RCR sources with flat and normal spectra, near which there are spots, over the number of sources with steep spectra. Secondly, the number of spots with positive amplitude on Planck maps that coincide within +/-2.5 arcmin with the coordinates of source-free areas on NVSS, FIRST maps and have the same sizes is on average almost one and a half times less than the number of spots that coincide with RCR objects. It is shown that RCR objects, near which there are no spots, have steeper spectra compared to the spectra of sources, near which spots are detected. The distribution of the spectral indices of spots in the range of 30--217 GHz was close to the distribution of the spectral indices of RCR sources in the range of 100MHz-8.5GHz and their median values almost coincided. This may indicate that the positive fluctuations on the Planck maps detected near RCR objects in the range of 30-217GHz are synchrotron in nature and may be associated with these objects. They can be manifestations of these objects or manifestations of their host galaxies and their environment in the submillimeter range. In the range of 353-857GHz, some of the detected spots can be classified as dusty. The spectra of RCR sources, near which such spots were detected, were steeper than the spectra of RCR objects, near which spots were detected only in the frequency channels 30-217GHz. The steeper the spectrum of the RCR object in the range of 100MHz-8.5GHz, the greater the value of the positive spectral index of the nearest spot in the range of 353-857GHz. The spots, whose two-frequency spectral indices indicate their dusty nature, may be associated with the high dust content in the host galaxies of RCR objects and the processes of star formation in them. It is also possible that the rise in the spectra at high frequencies may be caused by the presence of a signal from cold galactic dust on the frequency maps.
- ID:
- ivo://CDS.VizieR/J/MNRAS/503/2887
- Title:
- PNe angular diameters from SED modeling
- Short Name:
- J/MNRAS/503/2887
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- Powerful new, high-resolution, high-sensitivity, multifrequency, wide-field radio surveys such as the Australian Square Kilometre Array Pathfinder (ASKAP) Evolutionary Map of the Universe are emerging. They will offer fresh opportunities to undertake new determinations of useful parameters for various kinds of extended astrophysical phenomena. Here, we consider specific application to angular-size determinations of Planetary Nebulae (PNe) via a new radio continuum spectral energy distribution fitting technique. We show that robust determinations of angular size can be obtained, comparable to the best optical and radio observations but with the potential for consistent application across the population. This includes unresolved and/or heavily obscured PNe that are extremely faint or even non-detectable in the optical.
- ID:
- ivo://CDS.VizieR/J/other/PASA/37.29
- Title:
- POGS-II ExGal catalog
- Short Name:
- J/other/PASA/37.
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- The low-frequency linearly polarised radio source population is largely unexplored. However, a renaissance in low-frequency polarimetry has been enabled by pathfinder and precursor instruments for the Square Kilometre Array. In this second paper from the POlarised GaLactic and Extragalactic All-Sky MWA Survey-the POlarised GLEAM Survey, or POGS-we present the results from our all-sky MWA Phase I Faraday Rotation Measure survey. Our survey covers nearly the entire Southern sky in the Declination range -82{deg} to +30{deg} at a resolution between around three and seven arcminutes (depending on Declination) using data in the frequency range 169-231MHz. We have performed two targeted searches: the first covering 25489 square degrees of sky, searching for extragalactic polarised sources; the second covering the entire sky South of Declination +30{deg}, searching for known pulsars. We detect a total of 517 sources with 200MHz linearly polarised flux densities between 9.9mJy and 1.7Jy, of which 33 are known radio pulsars. All sources in our catalogues have Faraday rotation measures in the range -328.07rad/m^2^ to +279.62rad/m^2^. The Faraday rotation measures are broadly consistent with results from higher-frequency surveys, but with typically more than an order of magnitude improvement in the precision, highlighting the power of low-frequency polarisation surveys to accurately study Galactic and extragalactic magnetic fields. We discuss the properties of our extragalactic and known-pulsar source population, how the sky distribution relates to Galactic features, and identify a handful of new pulsar candidates among our nominally extragalactic source population.
- ID:
- ivo://CDS.VizieR/J/ApJ/733/69
- Title:
- Polarized DRAO sources
- Short Name:
- J/ApJ/733/69
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- The Dominion Radio Astrophysical Observatory Deep Field polarization study has been matched with the Spitzer Wide-Area Infrared Extragalactic Survey of the European Large Area Infrared Space Observatory Survey North 1 field. We have used Very Large Array observations with a total intensity rms of 87uJy/beam to match SWIRE counterparts to the radio sources. Infrared color analysis of our radio sample shows that the majority of polarized sources are elliptical galaxies with an embedded active galactic nucleus. Using available redshift catalogs, we found 429 radio sources of which 69 are polarized with redshifts in the range of 0.04<z<3.2. We find no correlation between redshift and percentage polarization for our sample. However, for polarized radio sources, we find a weak correlation between increasing percentage polarization and decreasing luminosity.
- ID:
- ivo://CDS.VizieR/J/ApJS/234/11
- Title:
- Pulsar rotation measures
- Short Name:
- J/ApJS/234/11
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present the measurements of Faraday rotation for 477 pulsars observed by the Parkes 64m radio telescope and the Green Bank 100m radio telescope. Using these results, along with previous measurements for pulsars and extragalactic sources, we analyze the structure of the large-scale magnetic field in the Galactic disk. Comparisons of rotation measures of pulsars in the disk at different distances, as well as with rotation measures of background radio sources beyond the disk, reveal large-scale reversals of the field directions between the spiral arms and interarm regions. We develop a model for the disk magnetic field, which can reproduce not only these reversals but also the distribution of the observed rotation measures of background sources.
- ID:
- ivo://CDS.VizieR/J/ApJ/746/156
- Title:
- Radio afterglow observations of GRBs
- Short Name:
- J/ApJ/746/156
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present a catalog of radio afterglow observations of gamma-ray bursts (GRBs) over a 14 year period from 1997 to 2011. Our sample of 304 afterglows consists of 2995 flux density measurements (including upper limits) at frequencies between 0.6 GHz and 660 GHz, with the majority of data taken at 8.5 GHz frequency band (1539 measurements). We use this data set to carry out a statistical analysis of the radio-selected sample. The detection rate of radio afterglows has stayed unchanged almost at 31% before and after the launch of the Swift satellite. The canonical long-duration GRB radio light curve at 8.5 GHz peaks at three to six days in the source rest frame, with a median peak luminosity of 10^31^ erg/s/Hz. The peak radio luminosities for short-hard bursts, X-ray flashes, and the supernova-GRB classes are an order of magnitude or more fainter than this value. There are clear relationships between the detectability of a radio afterglow and the fluence or energy of a GRB, and the X-ray or optical brightness of the afterglow. However, we find few significant correlations between these same GRB and afterglow properties and the peak radio flux density. We also produce synthetic light curves at centimeter and millimeter bands using a range of blast wave and microphysics parameters derived from multiwavelength afterglow modeling, and we use them to compare to the radio sample. Finding agreement, we extrapolate this behavior to predict the centimeter and millimeter behavior of GRBs observed by the Expanded Very Large Array and the Atacama Large Millimeter Array.
