A COMBINED LOW-RADIO FREQUENCY/X-RAY STUDY OF GALAXY GROUPS. I. GIANT METREWAVE RADIO TELESCOPE OBSERVATIONS AT 235 MHz AND 610 MHz

Journal Article · Tue May 10 04:00:00 EDT 2011 · Astrophysical Journal

DOI:https://doi.org/10.1088/0004-637X/732/2/95· OSTI ID:21576864

Giacintucci, Simona ^[1]; O'Sullivan, Ewan; Vrtilek, Jan; David, Laurence P; Mazzotta, Pasquale; Gitti, Myriam; Jones, Christine; Forman, William R ^[2]; Raychaudhury, Somak; Ponman, Trevor ^[3]; Venturi, Tiziana ^[4]; Athreya, Ramana M ^[5]; Clarke, Tracy E ^[6]; Murgia, Matteo ^[7]

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1. Department of Astronomy, University of Maryland, College Park, MD 20742-2421 (United States)
2. Harvard-Smithsonian Center for Astrophysics, 60 Garden Street, Cambridge, MA 02138 (United States)
3. School of Physics and Astronomy, University of Birmingham, Edgbaston, Birmingham B15 2TT (United Kingdom)
4. INAF-Istituto di Radioastronomia, via Gobetti 101, I-40129, Bologna (Italy)
5. IISER, Pune, Maharashtra 411 008 (India)
6. Naval Research Laboratory, 4555 Overlook Avenue SW, Code 7213, Washington, DC 20375 (United States)
7. INAF-Osservatorio Astronomico di Cagliari, Loc. Poggio dei Pini, Strada 54, I-09012 Capoterra (Italy)

We present new Giant Metrewave Radio Telescope observations at 235 MHz and 610 MHz of 18 X-ray bright galaxy groups. These observations are part of an extended project, presented here and in future papers, which combines low-frequency radio and X-ray data to investigate the interaction between central active galactic nuclei (AGNs) and the intra-group medium (IGM). The radio images show a very diverse population of group-central radio sources, varying widely in size, power, morphology, and spectral index. Comparison of the radio images with Chandra and XMM-Newton X-ray images shows that groups with significant substructure in the X-ray band and marginal radio emission at {approx}>1 GHz host low-frequency radio structures that correlate with substructures in IGM. Radio-filled X-ray cavities, the most evident form of AGN/IGM interaction in our sample, are found in half of the systems and are typically associated with small, low-, or mid-power double radio sources. Two systems, NGC5044 and NGC4636, possess multiple cavities, which are isotropically distributed around the group center, possibly due to group weather. In other systems the radio/X-ray correlations are less evident. However, the AGN/IGM interaction can manifest itself through the effects of the high-pressure medium on the morphology, spectral properties, and evolution of the radio-emitting plasma. In particular, the IGM can confine fading radio lobes in old/dying radio galaxies and prevent them from dissipating quickly. Evidence for radio emission produced by former outbursts that co-exist with current activity is found in six groups of the sample.

• OSTI ID: 21576864
• Journal Information: Astrophysical Journal, Journal Name: Astrophysical Journal Journal Issue: 2 Vol. 732; ISSN ASJOAB; ISSN 0004-637X
• Country of Publication: United States
• Language: English

Related Subjects

79 ASTRONOMY AND ASTROPHYSICS
ANTENNAS
CAVITIES
CORRELATIONS
COSMIC RADIO SOURCES
COSMIC RAY SOURCES
COSMIC X-RAY SOURCES
ELECTRICAL EQUIPMENT
ELECTROMAGNETIC RADIATION
ELECTRONIC EQUIPMENT
EMISSION
EQUIPMENT
GALAXIES
GALAXY NUCLEI
IONIZING RADIATIONS
MORPHOLOGY
RADIATIONS
RADIO EQUIPMENT
RADIO GALAXIES
RADIO TELESCOPES
RADIOWAVE RADIATION
TELESCOPES
X RADIATION
X-RAY GALAXIES