Browsing by Author "Stuardi, C."

Now showing 1 - 2 of 2
  • No Thumbnail Available
    Item
    Completing the 3CR Chandra Snapshot Survey: Extragalactic Radio Sources at High Redshift
    (2020) Jimenez-Gallardo, A.; Massaro, F.; Prieto, M. A.; Missaglia, V.; Stuardi, C.; Paggi, A.; Ricci, F.; Kraft, R. P.; Liuzzo, E.; Tremblay, G. R.; Baum, S. A.; O'Dea, C. P.; Wilkes, B. J.; Kuraszkiewicz, J.; Forman, W. R.; Harris, D. E.
    We present the analysis of nine radio sources belonging to the Third Cambridge Revised catalog (3CR) observed with Chandra during Cycle 20 in the redshift range between 1.5 and 2.5. This study completes the 3CR Chandra Snapshot Survey thus guaranteeing the X-ray coverage of all 3CR sources identified to date. This sample lists two compact steep spectrum sources, four radio galaxies, and three quasars. We detected X-ray emission from all nuclei, with the only exception of 3C 326.1 and 3C 454.1 and from radio lobes in six out of nine sources at a level of confidence larger than similar to 5 sigma. We measured X-ray fluxes and luminosities for all nuclei and lobes in the soft (0.5-1 keV), medium (1-2 keV), and hard (2-7 keV) X-ray bands. Since the discovered X-ray extended emission is spatially coincident with the radio structure in all cases, its origin could be due to inverse Compton (IC) scattering of the cosmic microwave background (CMB) occurring in radio lobes.
  • No Thumbnail Available
    Item
    Extended X-Ray Emission around FR II Radio Galaxies: Hot Spots, Lobes, and Galaxy Clusters
    (2021) Jimenez-Gallardo, A.; Massaro, F.; Paggi, A.; D'Abrusco, R.; Prieto, M. A.; Pena-Herazo, H. A.; Berta, V; Ricci, F.; Stuardi, C.; Wilkes, B. J.; O'Dea, C. P.; Baum, S. A.; Kraft, R. P.; Forman, W. R.; Jones, C.; Mingo, B.; Liuzzo, E.; Balmaverde, B.; Capetti, A.; Missaglia, V; Hardcastle, M. J.; Baldi, R. D.; Morabito, L. K.
    We present a systematic analysis of the extended X-ray emission discovered around 35 FR II radio galaxies from the revised Third Cambridge Catalog (3CR) Chandra Snapshot Survey with redshifts between 0.05 and 0.9. We aimed to (i) test for the presence of extended X-ray emission around FR II radio galaxies, (ii) investigate whether the extended emission origin is due to inverse Compton (IC) scattering of seed photons arising from the cosmic microwave background (CMB) or thermal emission from an intracluster medium (ICM), and (iii) test the impact of this extended emission on hot-spot detection. We investigated the nature of the extended X-ray emission by studying its morphology and compared our results with low-frequency radio observations (i.e., similar to 150 MHz) in the TGSS and LOFAR archives, as well as with optical images from Pan-STARRS. In addition, we optimized a search for X-ray counterparts of hot spots in 3CR FR II radio galaxies. We found statistically significant extended emission (>3 sigma confidence level) along the radio axis of similar to 90% and in the perpendicular direction of similar to 60% of the galaxies in our sample. We confirmed the detection of seven hot spots in the 0.5-3 keV energy range. In the cases where the emission in the direction perpendicular to the radio axis is comparable to that along the radio axis, we suggest that the underlying radiative process is thermal emission from the ICM. Otherwise, the dominant radiative process is likely nonthermal IC/CMB emission from lobes. We found that nonthermal IC/CMB is the dominant process in similar to 70% of the sources in our sample, while thermal emission from the ICM dominates in similar to 15% of them.