Fermi discovery of gamma-ray emission from NGC 1275

A. A. Abdo; M. Ackermann; M. Ajello; K. Asano; L. Baldini; J. Ballet; G. Barbiellini; D. Bastieri; B. M. Baughman; K. Bechtol; R. Bellazzini; R. D. Blandford; E. D. Bloom; E. Bonamente; A. W. Borgland; J. Bregeon; A. Brez; M. Brigida; P. Bruel; T. H. Burnett; G. A. Caliandro; R. A. Cameron; P. A. Caraveo; J. M. Casandjian; E. Cavazzuti; C. Cecchi; A. Celotti; A. Chekhtman; C. C. Cheung; J. Chiang; S. Ciprini; R. Claus; J. Cohen-Tanugi; S. Colafrancesco; L. R. Cominsky; J. Conrad; L. Costamante; C. D. Dermer; A. De Angelis; F. De Palma; S. W. Digel; D. Donato; E. Do Couto E Silva; P. S. Drell; R. Dubois; D. Dumora; C. Farnier; C. Favuzzi; J. Finke; W. B. Focke; M. Frailis; Y. Fukazawa; S. Funk; P. Fusco; F. Gargano; M. Georganopoulos; S. Germani; B. Giebels; N. Giglietto; F. Giordano; T. Glanzman; I. A. Grenier; M. H. Grondin; J. E. Grove; L. Guillemot; S. Guiriec; Y. Hanabata; A. K. Harding; R. C. Hartman; M. Hayashida; E. Hays; R. E. Hughes; G. Jóhannesson; A. S. Johnson; R. P. Johnson; W. N. Johnson; M. Kadler; T. Kamae; Y. Kanai; H. Katagiri; J. Kataoka; N. Kawai; M. Kerr; J. Knödlseder; F. Kuehn; M. Kuss; L. Latronico; M. Lemoine-Goumard; F. Longo; F. Loparco; B. Lott; M. N. Lovellette; P. Lubrano; G. M. Madejski; A. Makeev; M. N. Mazziotta; J. E. McEnery; C. Meurer; P. F. Michelson; W. Mitthumsiri; T. Mizuno; A. A. Moiseev; C. Monte; M. E. Monzani; A. Morselli; I. V. Moskalenko; S. Murgia; T. Nakamori; P. L. Nolan; J. P. Norris; E. Nuss; T. Ohsugi; N. Omodei; E. Orlando; J. F. Ormes; D. Paneque; J. H. Panetta; D. Parent; M. Pepe; M. Pesce-Rollins; F. Piron; T. A. Porter; S. Rainò; M. Razzano; A. Reimer; O. Reimer; T. Reposeur; S. Ritz; A. Y. Rodriguez; R. W. Romani; F. Ryde; H. F.W. Sadrozinski; R. Sambruna; D. Sanchez; A. Sander; R. Sato; P. M.Saz Parkinson; C. Sgrò; D. A. Smith; P. D. Smith; G. Spandre; P. Spinelli; J. L. Starck; M. S. Strickman; A. W. Strong; D. J. Suson; H. Tajima; H. Takahashi; T. Takahashi; T. Tanaka; G. B. Taylor; J. G. Thayer; D. J. Thompson; D. F. Torres; G. Tosti; Y. Uchiyama; T. L. Usher; N. Vilchez; V. Vitale; A. P. Waite; K. S. Wood; T. Ylinen; M. Ziegler; H. D. Aller; M. F. Aller; K. I. Kellermann; Y. Y. Kovalev; Yu A. Kovalev; M. L. Lister; A. B. Pushkarev

doi:10.1088/0004-637X/699/1/31

Fermi discovery of gamma-ray emission from NGC 1275

A. A. Abdo, M. Ackermann, M. Ajello, K. Asano, L. Baldini, J. Ballet, G. Barbiellini, D. Bastieri, B. M. Baughman, K. Bechtol, R. Bellazzini, R. D. Blandford, E. D. Bloom, E. Bonamente, A. W. Borgland, J. Bregeon, A. Brez, M. Brigida, P. Bruel, T. H. BurnettG. A. Caliandro, R. A. Cameron, P. A. Caraveo, J. M. Casandjian, E. Cavazzuti, C. Cecchi, A. Celotti, A. Chekhtman, C. C. Cheung, J. Chiang, S. Ciprini, R. Claus, J. Cohen-Tanugi, S. Colafrancesco, L. R. Cominsky, J. Conrad, L. Costamante, C. D. Dermer, A. De Angelis, F. De Palma, S. W. Digel, D. Donato, E. Do Couto E Silva, P. S. Drell, R. Dubois, D. Dumora, C. Farnier, C. Favuzzi, J. Finke, W. B. Focke, M. Frailis, Y. Fukazawa, S. Funk, P. Fusco, F. Gargano, M. Georganopoulos, S. Germani, B. Giebels, N. Giglietto, F. Giordano, T. Glanzman, I. A. Grenier, M. H. Grondin, J. E. Grove, L. Guillemot, S. Guiriec, Y. Hanabata, A. K. Harding, R. C. Hartman, M. Hayashida, E. Hays, R. E. Hughes, G. Jóhannesson, A. S. Johnson, R. P. Johnson, W. N. Johnson, M. Kadler, T. Kamae, Y. Kanai, H. Katagiri, J. Kataoka^*, N. Kawai, M. Kerr, J. Knödlseder, F. Kuehn, M. Kuss, L. Latronico, M. Lemoine-Goumard, F. Longo, F. Loparco, B. Lott, M. N. Lovellette, P. Lubrano, G. M. Madejski, A. Makeev, M. N. Mazziotta, J. E. McEnery, C. Meurer, P. F. Michelson, W. Mitthumsiri, T. Mizuno, A. A. Moiseev, C. Monte, M. E. Monzani, A. Morselli, I. V. Moskalenko, S. Murgia, T. Nakamori, P. L. Nolan, J. P. Norris, E. Nuss, T. Ohsugi, N. Omodei, E. Orlando, J. F. Ormes, D. Paneque, J. H. Panetta, D. Parent, M. Pepe, M. Pesce-Rollins, F. Piron, T. A. Porter, S. Rainò, M. Razzano, A. Reimer, O. Reimer, T. Reposeur, S. Ritz, A. Y. Rodriguez, R. W. Romani, F. Ryde, H. F.W. Sadrozinski, R. Sambruna, D. Sanchez, A. Sander, R. Sato, P. M.Saz Parkinson, C. Sgrò, D. A. Smith, P. D. Smith, G. Spandre, P. Spinelli, J. L. Starck, M. S. Strickman, A. W. Strong, D. J. Suson, H. Tajima, H. Takahashi, T. Takahashi, T. Tanaka, G. B. Taylor, J. G. Thayer, D. J. Thompson, D. F. Torres, G. Tosti, Y. Uchiyama, T. L. Usher, N. Vilchez, V. Vitale, A. P. Waite, K. S. Wood, T. Ylinen, M. Ziegler, H. D. Aller, M. F. Aller, K. I. Kellermann, Y. Y. Kovalev, Yu A. Kovalev, M. L. Lister, A. B. Pushkarev

^*Corresponding author for this work

School of Advanced Science and Engineering

Research output: Contribution to journal › Article › peer-review

161 Citations (Scopus)

Abstract

We report the discovery of high-energy (E > 100MeV) γ-ray emission from NGC1275, 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 NGC1275 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 F _γ = (2.10 0.23) × 10^-7 ph (>100MeV)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 F _γ < 3.72 × 10^-8ph (>100MeV)cm ^-2 s^-1 to the γ-ray flux from NGC1275. 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 NGC1275 is modeled with a simple one-zone synchrotron/synchrotron self-Compton model and a model with a decelerating jet flow.

Original language	English
Pages (from-to)	31-39
Number of pages	9
Journal	Astrophysical Journal
Volume	699
Issue number	1
DOIs	https://doi.org/10.1088/0004-637X/699/1/31
Publication status	Published - 2009

Keywords

Galaxies: active
Galaxies: individual (NGC 1275)
Galaxies: jets
Gamma rays: observations
Radiation mechanisms: non-thermal

ASJC Scopus subject areas

Astronomy and Astrophysics
Space and Planetary Science

Access to Document

10.1088/0004-637X/699/1/31

Cite this

Abdo, A. A., Ackermann, M., Ajello, M., Asano, K., Baldini, L., Ballet, J., Barbiellini, G., Bastieri, D., Baughman, B. M., Bechtol, K., Bellazzini, R., Blandford, R. D., Bloom, E. D., Bonamente, E., Borgland, A. W., Bregeon, J., Brez, A., Brigida, M., Bruel, P., ... Pushkarev, A. B. (2009). Fermi discovery of gamma-ray emission from NGC 1275. Astrophysical Journal, 699(1), 31-39. https://doi.org/10.1088/0004-637X/699/1/31

Abdo, AA, Ackermann, M, Ajello, M, Asano, K, Baldini, L, Ballet, J, Barbiellini, G, Bastieri, D, Baughman, BM, Bechtol, K, Bellazzini, R, Blandford, RD, Bloom, ED, Bonamente, E, Borgland, AW, Bregeon, J, Brez, A, Brigida, M, Bruel, P, Burnett, TH, Caliandro, GA, Cameron, RA, Caraveo, PA, Casandjian, JM, Cavazzuti, E, Cecchi, C, Celotti, A, Chekhtman, A, Cheung, CC, Chiang, J, Ciprini, S, Claus, R, Cohen-Tanugi, J, Colafrancesco, S, Cominsky, LR, Conrad, J, Costamante, L, Dermer, CD, De Angelis, A, De Palma, F, Digel, SW, Donato, D, Do Couto E Silva, E, Drell, PS, Dubois, R, Dumora, D, Farnier, C, Favuzzi, C, Finke, J, Focke, WB, Frailis, M, Fukazawa, Y, Funk, S, Fusco, P, Gargano, F, Georganopoulos, M, Germani, S, Giebels, B, Giglietto, N, Giordano, F, Glanzman, T, Grenier, IA, Grondin, MH, Grove, JE, Guillemot, L, Guiriec, S, Hanabata, Y, Harding, AK, Hartman, RC, Hayashida, M, Hays, E, Hughes, RE, Jóhannesson, G, Johnson, AS, Johnson, RP, Johnson, WN, Kadler, M, Kamae, T, Kanai, Y, Katagiri, H, Kataoka, J, Kawai, N, Kerr, M, Knödlseder, J, Kuehn, F, Kuss, M, Latronico, L, Lemoine-Goumard, M, Longo, F, Loparco, F, Lott, B, Lovellette, MN, Lubrano, P, Madejski, GM, Makeev, A, Mazziotta, MN, McEnery, JE, Meurer, C, Michelson, PF, Mitthumsiri, W, Mizuno, T, Moiseev, AA, Monte, C, Monzani, ME, Morselli, A, Moskalenko, IV, Murgia, S, Nakamori, T, Nolan, PL, Norris, JP, Nuss, E, Ohsugi, T, Omodei, N, Orlando, E, Ormes, JF, Paneque, D, Panetta, JH, Parent, D, Pepe, M, Pesce-Rollins, M, Piron, F, Porter, TA, Rainò, S, Razzano, M, Reimer, A, Reimer, O, Reposeur, T, Ritz, S, Rodriguez, AY, Romani, RW, Ryde, F, Sadrozinski, HFW, Sambruna, R, Sanchez, D, Sander, A, Sato, R, Parkinson, PMS, Sgrò, C, Smith, DA, Smith, PD, Spandre, G, Spinelli, P, Starck, JL, Strickman, MS, Strong, AW, Suson, DJ, Tajima, H, Takahashi, H, Takahashi, T, Tanaka, T, Taylor, GB, Thayer, JG, Thompson, DJ, Torres, DF, Tosti, G, Uchiyama, Y, Usher, TL, Vilchez, N, Vitale, V, Waite, AP, Wood, KS, Ylinen, T, Ziegler, M, Aller, HD, Aller, MF, Kellermann, KI, Kovalev, YY, Kovalev, YA, Lister, ML & Pushkarev, AB 2009, 'Fermi discovery of gamma-ray emission from NGC 1275', Astrophysical Journal, vol. 699, no. 1, pp. 31-39. https://doi.org/10.1088/0004-637X/699/1/31

@article{ea69e883aaea46859801beaab3b0bb04,

title = "Fermi discovery of gamma-ray emission from NGC 1275",

abstract = "We report the discovery of high-energy (E > 100MeV) γ-ray emission from NGC1275, 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 NGC1275 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 F γ = (2.10 0.23) × 10-7 ph (>100MeV)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 F γ < 3.72 × 10-8ph (>100MeV)cm -2 s-1 to the γ-ray flux from NGC1275. 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 NGC1275 is modeled with a simple one-zone synchrotron/synchrotron self-Compton model and a model with a decelerating jet flow.",

keywords = "Galaxies: active, Galaxies: individual (NGC 1275), Galaxies: jets, Gamma rays: observations, Radiation mechanisms: non-thermal",

author = "Abdo, {A. A.} and M. Ackermann and M. Ajello and K. Asano and L. Baldini and J. Ballet and G. Barbiellini and D. Bastieri and Baughman, {B. M.} and K. Bechtol and R. Bellazzini and Blandford, {R. D.} and Bloom, {E. D.} and E. Bonamente and Borgland, {A. W.} and J. Bregeon and A. Brez and M. Brigida and P. Bruel and Burnett, {T. H.} and Caliandro, {G. A.} and Cameron, {R. A.} and Caraveo, {P. A.} and Casandjian, {J. M.} and E. Cavazzuti and C. Cecchi and A. Celotti and A. Chekhtman and Cheung, {C. C.} and J. Chiang and S. Ciprini and R. Claus and J. Cohen-Tanugi and S. Colafrancesco and Cominsky, {L. R.} and J. Conrad and L. Costamante and Dermer, {C. D.} and {De Angelis}, A. and {De Palma}, F. and Digel, {S. W.} and D. Donato and {Do Couto E Silva}, E. and Drell, {P. S.} and R. Dubois and D. Dumora and C. Farnier and C. Favuzzi and J. Finke and Focke, {W. B.} and M. Frailis and Y. Fukazawa and S. Funk and P. Fusco and F. Gargano and M. Georganopoulos and S. Germani and B. Giebels and N. Giglietto and F. Giordano and T. Glanzman and Grenier, {I. A.} and Grondin, {M. H.} and Grove, {J. E.} and L. Guillemot and S. Guiriec and Y. Hanabata and Harding, {A. K.} and Hartman, {R. C.} and M. Hayashida and E. Hays and Hughes, {R. E.} and G. J{\'o}hannesson and Johnson, {A. S.} and Johnson, {R. P.} and Johnson, {W. N.} and M. Kadler and T. Kamae and Y. Kanai and H. Katagiri and J. Kataoka and N. Kawai and M. Kerr and J. Kn{\"o}dlseder and F. Kuehn and M. Kuss and L. Latronico and M. Lemoine-Goumard and F. Longo and F. Loparco and B. Lott and Lovellette, {M. N.} and P. Lubrano and Madejski, {G. M.} and A. Makeev and Mazziotta, {M. N.} and McEnery, {J. E.} and C. Meurer and Michelson, {P. F.} and W. Mitthumsiri and T. Mizuno and Moiseev, {A. A.} and C. Monte and Monzani, {M. E.} and A. Morselli and Moskalenko, {I. V.} and S. Murgia and T. Nakamori and Nolan, {P. L.} and Norris, {J. P.} and E. Nuss and T. Ohsugi and N. Omodei and E. Orlando and Ormes, {J. F.} and D. Paneque and Panetta, {J. H.} and D. Parent and M. Pepe and M. Pesce-Rollins and F. Piron and Porter, {T. A.} and S. Rain{\`o} and M. Razzano and A. Reimer and O. Reimer and T. Reposeur and S. Ritz and Rodriguez, {A. Y.} and Romani, {R. W.} and F. Ryde and Sadrozinski, {H. F.W.} and R. Sambruna and D. Sanchez and A. Sander and R. Sato and Parkinson, {P. M.Saz} and C. Sgr{\`o} and Smith, {D. A.} and Smith, {P. D.} and G. Spandre and P. Spinelli and Starck, {J. L.} and Strickman, {M. S.} and Strong, {A. W.} and Suson, {D. J.} and H. Tajima and H. Takahashi and T. Takahashi and T. Tanaka and Taylor, {G. B.} and Thayer, {J. G.} and Thompson, {D. J.} and Torres, {D. F.} and G. Tosti and Y. Uchiyama and Usher, {T. L.} and N. Vilchez and V. Vitale and Waite, {A. P.} and Wood, {K. S.} and T. Ylinen and M. Ziegler and Aller, {H. D.} and Aller, {M. F.} and Kellermann, {K. I.} and Kovalev, {Y. Y.} and Kovalev, {Yu A.} and Lister, {M. L.} and Pushkarev, {A. B.}",

year = "2009",

doi = "10.1088/0004-637X/699/1/31",

language = "English",

volume = "699",

pages = "31--39",

journal = "Astrophysical Journal",

issn = "0004-637X",

publisher = "IOP Publishing Ltd.",

number = "1",

}

TY - JOUR

T1 - Fermi discovery of gamma-ray emission from NGC 1275

AU - Abdo, A. A.

AU - Ackermann, M.

AU - Ajello, M.

AU - Asano, K.

AU - Baldini, L.

AU - Ballet, J.

AU - Barbiellini, G.

AU - Bastieri, D.

AU - Baughman, B. M.

AU - Bechtol, K.

AU - Bellazzini, R.

AU - Blandford, R. D.

AU - Bloom, E. D.

AU - Bonamente, E.

AU - Borgland, A. W.

AU - Bregeon, J.

AU - Brez, A.

AU - Brigida, M.

AU - Bruel, P.

AU - Burnett, T. H.

AU - Caliandro, G. A.

AU - Cameron, R. A.

AU - Caraveo, P. A.

AU - Casandjian, J. M.

AU - Cavazzuti, E.

AU - Cecchi, C.

AU - Celotti, A.

AU - Chekhtman, A.

AU - Cheung, C. C.

AU - Chiang, J.

AU - Ciprini, S.

AU - Claus, R.

AU - Cohen-Tanugi, J.

AU - Colafrancesco, S.

AU - Cominsky, L. R.

AU - Conrad, J.

AU - Costamante, L.

AU - Dermer, C. D.

AU - De Angelis, A.

AU - De Palma, F.

AU - Digel, S. W.

AU - Donato, D.

AU - Do Couto E Silva, E.

AU - Drell, P. S.

AU - Dubois, R.

AU - Dumora, D.

AU - Farnier, C.

AU - Favuzzi, C.

AU - Finke, J.

AU - Focke, W. B.

AU - Frailis, M.

AU - Fukazawa, Y.

AU - Funk, S.

AU - Fusco, P.

AU - Gargano, F.

AU - Georganopoulos, M.

AU - Germani, S.

AU - Giebels, B.

AU - Giglietto, N.

AU - Giordano, F.

AU - Glanzman, T.

AU - Grenier, I. A.

AU - Grondin, M. H.

AU - Grove, J. E.

AU - Guillemot, L.

AU - Guiriec, S.

AU - Hanabata, Y.

AU - Harding, A. K.

AU - Hartman, R. C.

AU - Hayashida, M.

AU - Hays, E.

AU - Hughes, R. E.

AU - Jóhannesson, G.

AU - Johnson, A. S.

AU - Johnson, R. P.

AU - Johnson, W. N.

AU - Kadler, M.

AU - Kamae, T.

AU - Kanai, Y.

AU - Katagiri, H.

AU - Kataoka, J.

AU - Kawai, N.

AU - Kerr, M.

AU - Knödlseder, J.

AU - Kuehn, F.

AU - Kuss, M.

AU - Latronico, L.

AU - Lemoine-Goumard, M.

AU - Longo, F.

AU - Loparco, F.

AU - Lott, B.

AU - Lovellette, M. N.

AU - Lubrano, P.

AU - Madejski, G. M.

AU - Makeev, A.

AU - Mazziotta, M. N.

AU - McEnery, J. E.

AU - Meurer, C.

AU - Michelson, P. F.

AU - Mitthumsiri, W.

AU - Mizuno, T.

AU - Moiseev, A. A.

AU - Monte, C.

AU - Monzani, M. E.

AU - Morselli, A.

AU - Moskalenko, I. V.

AU - Murgia, S.

AU - Nakamori, T.

AU - Nolan, P. L.

AU - Norris, J. P.

AU - Nuss, E.

AU - Ohsugi, T.

AU - Omodei, N.

AU - Orlando, E.

AU - Ormes, J. F.

AU - Paneque, D.

AU - Panetta, J. H.

AU - Parent, D.

AU - Pepe, M.

AU - Pesce-Rollins, M.

AU - Piron, F.

AU - Porter, T. A.

AU - Rainò, S.

AU - Razzano, M.

AU - Reimer, A.

AU - Reimer, O.

AU - Reposeur, T.

AU - Ritz, S.

AU - Rodriguez, A. Y.

AU - Romani, R. W.

AU - Ryde, F.

AU - Sadrozinski, H. F.W.

AU - Sambruna, R.

AU - Sanchez, D.

AU - Sander, A.

AU - Sato, R.

AU - Parkinson, P. M.Saz

AU - Sgrò, C.

AU - Smith, D. A.

AU - Smith, P. D.

AU - Spandre, G.

AU - Spinelli, P.

AU - Starck, J. L.

AU - Strickman, M. S.

AU - Strong, A. W.

AU - Suson, D. J.

AU - Tajima, H.

AU - Takahashi, H.

AU - Takahashi, T.

AU - Tanaka, T.

AU - Taylor, G. B.

AU - Thayer, J. G.

AU - Thompson, D. J.

AU - Torres, D. F.

AU - Tosti, G.

AU - Uchiyama, Y.

AU - Usher, T. L.

AU - Vilchez, N.

AU - Vitale, V.

AU - Waite, A. P.

AU - Wood, K. S.

AU - Ylinen, T.

AU - Ziegler, M.

AU - Aller, H. D.

AU - Aller, M. F.

AU - Kellermann, K. I.

AU - Kovalev, Y. Y.

AU - Kovalev, Yu A.

AU - Lister, M. L.

AU - Pushkarev, A. B.

PY - 2009

Y1 - 2009

N2 - We report the discovery of high-energy (E > 100MeV) γ-ray emission from NGC1275, 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 NGC1275 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 F γ = (2.10 0.23) × 10-7 ph (>100MeV)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 F γ < 3.72 × 10-8ph (>100MeV)cm -2 s-1 to the γ-ray flux from NGC1275. 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 NGC1275 is modeled with a simple one-zone synchrotron/synchrotron self-Compton model and a model with a decelerating jet flow.

AB - We report the discovery of high-energy (E > 100MeV) γ-ray emission from NGC1275, 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 NGC1275 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 F γ = (2.10 0.23) × 10-7 ph (>100MeV)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 F γ < 3.72 × 10-8ph (>100MeV)cm -2 s-1 to the γ-ray flux from NGC1275. 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 NGC1275 is modeled with a simple one-zone synchrotron/synchrotron self-Compton model and a model with a decelerating jet flow.

KW - Galaxies: active

KW - Galaxies: individual (NGC 1275)

KW - Galaxies: jets

KW - Gamma rays: observations

KW - Radiation mechanisms: non-thermal

UR - http://www.scopus.com/inward/record.url?scp=68149150068&partnerID=8YFLogxK

UR - http://www.scopus.com/inward/citedby.url?scp=68149150068&partnerID=8YFLogxK

U2 - 10.1088/0004-637X/699/1/31

DO - 10.1088/0004-637X/699/1/31

M3 - Article

AN - SCOPUS:68149150068

SN - 0004-637X

VL - 699

SP - 31

EP - 39

JO - Astrophysical Journal

JF - Astrophysical Journal

IS - 1

ER -

Fermi discovery of gamma-ray emission from NGC 1275

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