FERMI DISCOVERY OF GAMMA-RAY EMISSION FROM NGC 1275

By A. Abdo, M. Ackermann, M. Ajello, K. Asano, L. Baldini, J. Ballet, G. Barbiellini, D. Bastieri, B. Baughman, K. Bechtol and 160 more. 2009

168 citations recorded by the source corpus.

We report the discovery of high-energy (E > 100 MeV) γ-ray emission from NGC 1275, a giant elliptical galaxy lying at the center of the Perseus cluster of galaxies, based on observations made with the Large Area Telescope (LAT) of the Fermi Gamma-ray Space Telescope. The positional center of the γ-ray source is only ≈3′ away from the NGC 1275 nucleus, well within the 95% LAT error circle of ≈5′. The spatial distribution of γ-ray photons is consistent with a point source. The average flux and power-law photon index measured with the LAT from 2008 August 4 to 2008 December 5 are Fγ = (2.10 ± 0.23) × 10−7 ph (>100 MeV) cm−2 s−1 and Γ = 2.17 ± 0.05, respectively. The measurements are statistically consistent with constant flux during the four-month LAT observing period. Previous EGRET observations gave an upper limit of Fγ < 3.72 × 10−8 ph (>100 MeV) cm−2 s−1 to the γ-ray flux from NGC 1275. This indicates that the source is variable on timescales of years to decades, and therefore restricts the fraction of emission that can be produced in extended regions of the galaxy cluster. Contemporaneous and historical radio observations are also reported. The broadband spectrum of NGC 1275 is modeled with a simple one-zone synchrotron/synchrotron self-Compton model and a model with a decelerating jet flow.

Subfields: Astronomy and Astrophysics, Nuclear and High Energy Physics

View Paper: https://www.semanticscholar.org/paper/6cd6175efdc87765c6fba16bac3e4ba7607ac13d

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Citations in the corpus

FERMI LARGE AREA TELESCOPE OBSERVATIONS OF MISALIGNED ACTIVE GALACTIC NUCLEI (2010, methodology): “Dedicated papers have been recently published or are in preparation on three of these, namely, NGC 1275 (Abdo et al. 2009b), M87 (Abdo et al. 2009c), and Cen A (Abdo et al. 2010c, 2010d).”
CONTRIBUTION OF GAMMA-RAY-LOUD RADIO GALAXIES’ CORE EMISSIONS TO THE COSMIC MeV AND GeV GAMMA-RAY BACKGROUND RADIATION (2011, methodology): “The viewing angle of NGC 1275, M 87, and Cen A is derived as 25◦, 10◦, and 30◦ by SED fitting (Abdo et al. 2009b, 2009c, 2010c), respectively.”
Diffuse Radio Emission from Galaxy Clusters (2019, background): “In addition, the Fermi-II acceleration by postshock turbulence via transit-time-damping resonance has been invoked to explain the broad downstream steepening of the radio spectrum behind the observed radio shocks (Brunetti & Lazarian 2007; Kang et al. 2017; Kang 2017).”
Constraints on dark matter annihilation in clusters of galaxies with the Fermi large area telescope (2010, methodology): “Starting from the best candidate clusters, we removed from the sample the Perseus cluster since its central galaxy, NGC 1275, hosts a bright gamma-ray AGN [11], the Ophiuchus cluster, which lies near the Galactic Center, and the Norma cluster, which lies near the Galactic plane.”
Jet opening angles and gamma-ray brightness of AGN (2009, methodology): “Hereafter we refer to the Fermi LAT 3-month bright source list (Abdo et al. 2009a) when using the term LAT-detected.”
THE THIRD CATALOG OF ACTIVE GALACTIC NUCLEI DETECTED BY THE FERMI LARGE AREA TELESCOPE (2015, methodology): “M 87 was one of the first new Fermi-LAT detections (Abdo et al. 2009d) of a source classified as a non-blazar object, being a low-power Fanaroff & Riley (1974) type-I (FRI) radio galaxy.”
SEARCH FOR COSMIC-RAY-INDUCED GAMMA-RAY EMISSION IN GALAXY CLUSTERS (2013, methodology): “We also investigate the spectral behavior of the excesses towards Abell 1367 and Abell 3112, by replacing the hadronic CR spectrum with a featureless power-law, such that the flux becomes: FPLγ (E)=Aγ × FCRγ,exp(> 500 MeV) × (1 − Γ)× E −Γ E1−Γmax − E1−Γmin , (6) where Γ is the spectral index, and Em”
FERMI LARGE AREA TELESCOPE GAMMA-RAY DETECTION OF THE RADIO GALAXY M87 (2009, methodology): “The initial LAT detection of M87 resulted from nominal processing of 6-months of all-sky survey data, as was applied to the initial 3-month dataset described in Abdo et al. (2009a), with a test statistic (Mattox et al. 1996),TS ∼ 60.”
FERMI LARGE AREA TELESCOPE VIEW OF THE CORE OF THE RADIO GALAXY CENTAURUS A (2010, methodology): “In the companion LAT Bright AGN169 Sample paper (LBAS; Abdo et al. 2009c) to the BSL, a single power-law fit was reported, which170 gave F (>100 MeV) = 2.15 (± 0.45) × 10−7 ph cm−2 s−1 with photon index, Γ = 2.91 ± 0.18,171 and a peak flux on a ∼1 week timescale of (3.23 ± 0.80) × 10−7 ph cm−2 s−1.”
FERMI/LARGE AREA TELESCOPE BRIGHT GAMMA-RAY SOURCE LIST (2009, methodology): “In the case of AGN, many of the associations have high confidence (Abdo et al. 2009c).”
BLAZARS AS ULTRA-HIGH-ENERGY COSMIC-RAY SOURCES: IMPLICATIONS FOR TeV GAMMA-RAY OBSERVATIONS (2011, background): “Cen A (Abdo et al. 2010d), M87 (Abdo et al. 2009c), and NGC 1275 (Abdo et al. 2009b; Kataoka et al. 2010; Brown & Adams 2011) have also been detected at GeV energies.”
The extragalactic background light and the gamma-ray opacity of the universe (2012, background): “Starburst galaxies: The detection of starburst galaxies M82 (Acciari et al., 2009b; Abdo et al., 2009) and NGC 253 (Acero et al., 2009), potentially opened a new wavelength regime for studying the EBL.”
THE FIRST CATALOG OF ACTIVE GALACTIC NUCLEI DETECTED BY THE FERMI LARGE AREA TELESCOPE (2010, background): “Abdo et al. (2009f) noted that, as the number of LAT detections increased, source confusion was likely to be more of a problem, and indeed, the 1LAC includes 35 LAT sources that are associated with more than one AGN (for a total of 73 such associations).”