The 3CR Chandra snapshot survey: extragalactic radio sources with 0.5$<z<$1.0

Abstract

This paper presents the analysis of Chandra X-ray snapshot observations of a subsample of the extragalactic sources listed in the revised Third Cambridge radio catalog (3CR), previously lacking X-ray observations and thus observed during Chandra Cycle 15. This data set extends the current Chandra coverage of the 3CR extragalactic catalog up to redshift $z$=1.0. Our sample includes 22 sources consisting of one compact steep spectrum (CSS) source, three quasars (QSOs), and 18 FR\,II radio galaxies. As in our previous analyses, here we report the X-ray detections of radio cores and extended structures (i.e., knots, hotspots and lobes) for all sources in the selected sample. We measured their X-ray intensities in three energy ranges: soft (0.5--1 keV), medium (1--2 keV) and hard (2-7 keV) and we also performed standard X-ray spectral analysis for brighter nuclei. All radio nuclei in our sample have an X-ray counterpart. We also discovered X-ray emission associated with the eastern knot of 3CR\,154, with radio hotspots in 3CR\,41, 3CR\,54 and 3CR\,225B and with the southern lobe of 3CR\,107. Extended X-ray radiation around the nuclei 3CR\,293.1 and 3CR\,323 on a scale of few tens kpc was also found. X-ray extended emission, potentially arising from the hot gas in the intergalactic medium and/or due to the high energy counterpart of lobes, is detected for 3CR\,93, 3CR\,154, 3CR\,292 and 3CR\, 323 over a few hundreds kpc-scale. Finally, this work also presents an update on the state-of-the-art of Chandra and XMM-Newton observations for the entire 3CR sample.