FERMI LARGE AREA TELESCOPE VIEW OF THE CORE OF THE RADIO GALAXY CENTAURUS A
| dc.contributor.author | Çelik, Ö. | |
| dc.contributor.author | Davis, D. S. | |
| dc.contributor.author | Georganopoulos, M. | |
| dc.contributor.author | Ojha, R. | |
| dc.date.accessioned | 2020-04-06T12:44:15Z | |
| dc.date.available | 2020-04-06T12:44:15Z | |
| dc.date.issued | 2010-07-29 | |
| dc.description.abstract | We present γ-ray observations with the Large Area Telescope (LAT) on board the Fermi Gamma-Ray Space Telescope of the nearby radio galaxy Centaurus A (Cen A). The previous EGRET detection is confirmed, and the localization is improved using data from the first 10 months of Fermi science operation. In previous work, we presented the detection of the lobes by the LAT; in this work, we concentrate on the γ-ray core of Cen A. Flux levels as seen by the LAT are not significantly different from that found by EGRET, nor is the extremely soft LAT spectrum (Γ = 2.67 ± 0.10stat ± 0.08sys where the photon flux is Φ ∝ E ⁻ᴦ). The LAT core spectrum, extrapolated to higher energies, is marginally consistent with the non-simultaneous HESS spectrum of the source. The LAT observations are complemented by simultaneous observations from Suzaku, the Swift Burst Alert Telescope and X-ray Telescope, and radio observations with the Tracking Active Galactic Nuclei with Austral Milliarcsecond Interferometry program, along with a variety of non-simultaneous archival data from a variety of instruments and wavelengths to produce a spectral energy distribution (SED). We fit this broadband data set with a single-zone synchrotron/synchrotron self-Compton model, which describes the radio through GeV emission well, but fails to account for the non-simultaneous higher energy TeV emission observed by HESS from 2004 to 2008. The fit requires a low Doppler factor, in contrast to BL Lac objects which generally require larger values to fit their broadband SEDs. This indicates that the γ-ray emission originates from a slower region than that from BL Lac objects, consistent with previous modeling results from Cen A. This slower region could be a slower moving layer around a fast spine, or a slower region farther out from the black hole in a decelerating flow. The fit parameters are also consistent with Cen A being able to accelerate ultra-high energy cosmic-rays, as hinted at by results from the Auger observatory. | en_US |
| dc.description.sponsorship | The Fermi LAT Collaboration acknowledges generous ongoing support from a number of agencies and institutes that have supported both the development and the operation of the LAT as well as scientific data analysis. These include the National Aeronautics and Space Administration and the Department of Energy in the United States, the Commissariat à l'Energie Atomique and the Centre National de la Recherche Scientifique/Institut National de Physique Nucléaire et de Physique des Particules in France, the Agenzia Spaziale Italiana and the Istituto Nazionale di Fisica Nucleare in Italy, the Ministry of Education, Culture, Sports, Science and Technology (MEXT), High Energy Accelerator Research Organization (KEK) and Japan Aerospace Exploration Agency (JAXA) in Japan, and the K. A. Wallenberg Foundation, the Swedish Research Council and the Swedish National Space Board in Sweden. Additional support for science analysis during the operations phase is gratefully acknowledged from the Istituto Nazionale di Astrofisica in Italy and the Centre National d'Études Spatiales in France. We are grateful to the anonymous referee for useful comments which have improved the manuscript. We thank N. Odegard for providing us with the WMAP image and the Suzaku team for their calibration and satellite operation. We also acknowledge the Swift Team and the Swift/XRT monitoring program efforts as well as Swift analysis supported by NASA grants NNX08AV77G and NNX09AU07G. | en_US |
| dc.description.uri | https://iopscience.iop.org/article/10.1088/0004-637X/719/2/1433 | en_US |
| dc.format.extent | 12 pages | en_US |
| dc.genre | journal articles | en_US |
| dc.identifier | doi:10.13016/m2owap-lfck | |
| dc.identifier.citation | Çelik Ö, Davis D. S, Georganopoulos M, Ojha R, FERMI LARGE AREA TELESCOPE VIEW OF THE CORE OF THE RADIO GALAXY CENTAURUS A, The Astrophysical Journal,https://iopscience.iop.org/article/10.1088/0004-637X/719/2/1433 | en_US |
| dc.identifier.uri | http://hdl.handle.net/11603/17830 | |
| dc.identifier.uri | http://simbad.u-strasbg.fr/simbad/sim-ref?querymethod=bib&simbo=on&submit=submit+bibcode&bibcode=2010ApJ...719.1433A | |
| dc.identifier.uri | https://ned.ipac.caltech.edu/cgi-bin/objsearch?search_type=Search&refcode=2010ApJ...719.1433A | |
| dc.identifier.uri | https://heasarc.gsfc.nasa.gov/xamin/xamin.jsp?bibcode=2010ApJ%2E%2E%2E719%2E1433A | |
| dc.language.iso | en_US | en_US |
| dc.publisher | IOP | en_US |
| dc.relation.isAvailableAt | The University of Maryland, Baltimore County (UMBC) | |
| dc.relation.ispartof | UMBC Physics Department Collection | |
| dc.relation.ispartof | UMBC Faculty Collection | |
| dc.relation.ispartof | UMBC Center for Space Sciences and Technology (CSST) / Center for Research and Exploration in Space Sciences & Technology II (CRSST II) | |
| dc.rights | This item is likely protected under Title 17 of the U.S. Copyright Law. Unless on a Creative Commons license, for uses protected by Copyright Law, contact the copyright holder or the author. | |
| dc.rights | Public Domain Mark 1.0 | * |
| dc.rights | This work was written as part of one of the author's official duties as an Employee of the United States Government and is therefore a work of the United States Government. In accordance with 17 U.S.C. 105, no copyright protection is available for such works under U.S. Law | |
| dc.rights.uri | http://creativecommons.org/publicdomain/mark/1.0/ | * |
| dc.title | FERMI LARGE AREA TELESCOPE VIEW OF THE CORE OF THE RADIO GALAXY CENTAURUS A | en_US |
| dc.type | Text | en_US |