A VLA search for 5 GHz radio transients and variables at low Galactic latitudes

Abstract

We present the results of a 5 GHz survey with the Very Large Array, designed to search for short-lived (<1 day) transients and to characterize the variability of radio sources at milli-Jansky levels. A total sky area of 2.66 deg^2, spread over 141 fields at low Galactic latitudes was observed 16 times with a cadence sampling timescales of days, months and years. Most of the data were searched for transients in near real time. Candidates were followed up using visible light telescopes (1-2 hr delays) and the X-Ray Telescope on board the Swift satellite. The final processing of the data revealed a single possible transient with a flux density of 2.4 mJy. This implies a transients, >1.8 mJy, sky surface density of 0.039 (-0.032/+0.13) deg^-2. This areal density is consistent with the sky surface density of transients from the Bower et al. survey extrapolated to 1.8 mJy. Our observed transient areal density is consistent with a Neutron Stars (NSs) origin for these events. Furthermore, we use the data to measure the sources variability on days to years time scales, and we present the variability structure function of 5 GHz sources. The mean structure function shows a fast increase on ~1 day time scale, followed by a slower increase on time scales of up to 10 days. On time scales between 10-60 days the structure function is roughly constant. We find that >30% of the unresolved sources brighter than 1.8 mJy are variable at the >4 sigma confidence level, presumably due mainly to refractive scintillation.

Submitted to ApJ, 19 pages, 8 figures

References in corpus (11)

• Five-Year Wilkinson Microwave Anisotropy Probe (WMAP) Observations: Cosmological Interpretation
• A bright millisecond radio burst of extragalactic origin
• An extremely luminous panchromatic outburst from the nucleus of a distant galaxy
• The Automated Palomar 60-Inch Telescope
• The Molonglo Galactic Plane Survey (MGPS-2): Compact Source Catalogue
• The Micro-Arcsecond Scintillation-Induced Variability (MASIV) Survey II: The First Four Epochs
• SubmilliJansky Transients in Archival Radio Observations
• The structure function of variable 1.4 GHz radio sources based on NVSS and FIRST observations
• An automated archival VLA transients survey
• A Search for Radio Transients in VLA Archival Images of the 3C 286 Field
• The Allen Telescope Array Twenty-centimeter Survey -- A 700-Square-Degree, Multi-Epoch Radio Dataset -- II: Individual Epoch Transient Statistics

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