Radio sources of the survey on the declination of the pulsar in Crab Nebula

TL;DR

This study analyzed 205 bright radio sources near the Crab pulsar's declination at 4.7 GHz, revealing spectral data, variability patterns, and optical identifications, with some sources observed at higher frequencies for the first time.

Contribution

It provides new radio spectra for sources, including first-time higher frequency data, and investigates variability over different timescales in a specific sky region.

Findings

First-time higher frequency data for some sources.

Detected significant variability in blazar B2 1324+22.

Identified all sources with optical and infrared objects.

Abstract

The results of the analysis of 205 brightest sources ( $S>15$ mJy), which were found in the sky survey at the declination of the pulsar in the Crab Nebula, are presented. The survey was conducted at a frequency of 4.7~GHz using a three-beam radiometer complex installed in the focus of the Western Sector of the RATAN-600 radio telescope in 2018-2019. Based on the measurements and data collected in the database of astrophysical catalogs CATS built radio spectra of objects. For a quarter of all detected sources, data at a frequency higher than 4~GHz were obtained for the first time, and for the rest, they were appended. The variability of radiation sources on the scales of the year, from days to months, was studied. The greatest change in the radio flux was found in the blazar B2~1324+22. The search for daily variability was carried out for 26 the brightest sources with an average value of $S_{4.7} \sim 250$ mJy. All sources are identified with objects from optical and infrared catalogs. Radio luminosity is calculated for 112 objects with a known redshift.