| Contributors: |
Noutsos, A; Abdo, Aa; Ackermann, M; Ajello, M; Ballet, J; Barbiellini, G; Baring, Mg; Bastieri, D; Bechtol, K; Bellazzini, R; Berenji, B; Bonamente, E; Borgland, Aw; Bregeon, J; Brez, A; Brigida, M; Bruel, P; Buehler, R; Busetto, G; Caliandro, Ga; Cameron, Ra; Camilo, F; Caraveo, Pa; Casandjian, Jm; Cecchi, C; Celik, O; Chaty, S; Chekhtman, A; Chiang, J; Ciprini, S; Claus, R; Cognard, I; Cohen Tanugi, J; Colafrancesco, S; Cutini, S; Dermer, Cd; de Palma, F; Drell, P; Dumora, D; Ea, Cm; Favuzzi, Cecilia; Ferrara, Ec; Focke, Wb; Frailis, M; Freire, Pcc; Fukazawa, Y; Funk, S; Fusco, P; Gargano, F; Germani, S; Giglietto, Nicola; Giordano, F; Giroletti, M; Godfrey, G; Grandi, P; Grenier, Ia; Grove, Je; Guillemot, L; Guiriec, S; Harding, Ak; Hughes, Re; Jackson, M; Johannesson, G; Johnson, A; Johnson, Tj; Johnson, Wn; Johnston, S; Kamae, T; Katagiri, H; Kataoka, J; Knodlseder, J; Kramer, M; Kuss, M; Lande, J; Lee, Sh; Longo, F; Loparco, F; Lovellette, Mn; Lubrano, P; Lyne, Ag; Makeev, A; Marelli, M; Mazziotta, Mn; Mcenery, Je; Mehault, J; Michelson, Pf; Mizuno, T; Monte, C; Monzani, Me; Morselli, A; Moskalenko, Iv; Murgia, S; Naumann Godo, M; Nolan, Pl; Nuss, E; Ohsugi, T; Okumura, A; Omodei, N; Orlando, E; Ormes, Jf |
| Description: |
We report on the first year of Fermi gamma-ray observations of pulsed high-energy emission from the old PSR J2043 + 2740. The study of the gamma-ray efficiency of such old pulsars gives us an insight into the evolution of pulsars' ability to emit in gamma rays as they age. The gamma-ray light curve of this pulsar above 0.1 GeV is clearly defined by two sharp peaks, 0.353 +/- 0.035 periods apart. We have combined the gamma-ray profile characteristics of PSR J2043 + 2740 with the geometrical properties of the pulsar's radio emission, derived from radio-polarization data, and constrained the pulsar-beam geometry in the framework of a two-pole caustic (TPC) and an outer gap (OG) model. The ranges of magnetic inclination and viewing angle were determined to be {alpha, zeta} similar to {52 degrees-57 degrees, 61 degrees-68 degrees} for the TPC model, and {alpha, zeta} similar to {62 degrees-73 degrees, 74 degrees-81 degrees} and {alpha, zeta} similar to {72 degrees-83 degrees, 60 degrees-75 degrees} for the OG model. Based on this geometry, we assess possible birth locations for this pulsar and derive a likely proper motion, sufficiently high to be measurable with VLBI. At a characteristic age of 1.2 Myr, PSR J2043 + 2740 is the third oldest of all discovered, non-recycled, gamma-ray pulsars: it is twice as old as the next oldest, PSR J0357 + 32, and younger only than the recently discovered PSR J1836 + 5925 and PSR J2055 + 25, both of which are at least five and ten times less energetic, respectively. |