Fermi large area telescope observations of the vela pulsar

A. A. Abdo, M. Ackermann, W. B. Atwood, R. Bagagli, L. Baldini, J. Ballet, D. L. Band, G. Barbiellini, M. G. Baring, J. Bartelt, D. Bastieri, B. M. Baughman, K. Bechtol, F. Bellardi, R. Bellazzini, B. Berenji, D. Bisello, R. D. Blandford, E. D. Bloom, J. R. BogartE. Bonamente, A. W. Borgland, A. Bouvier, J. Bregeon, A. Brez, M. Brigida, P. Bruel, T. H. Burnett, G. A. Caliandro, R. A. Cameron, F. Camilo, P. A. Caraveo, J. M. Casandjian, M. Ceccanti, C. Cecchi, E. Charles, A. Chekhtman, C. C. Cheung, J. Chiang, S. Ciprini, R. Claus, I. Cognard, J. Cohen-Tanugi, L. R. Cominsky, J. Conrad, R. Corbet, L. Corucci, S. Cutini, D. S. Davis, M. Deklotz, C. D. Dermer, A. De Angelis, F. De Palma, S. W. Digel, M. Dormody, E. Do Couto E Silva, P. S. Drell, R. Dubois, D. Dumora, C. Espinoza, C. Farnier, C. Favuzzi, D. L. Flath, P. Fleury, W. B. Focke, M. Frailis, P. C C Friere, Y. Fukazawa, S. Funk, P. Fusco, F. Gargano, D. Gasparrini, N. Gehrels, S. Germani, R. Giannitrapani, B. Giebels, N. Giglietto, F. Giordano, T. Glanzman, G. Godfrey, E. V. Gotthelf, I. A. Grenier, M. H. Grondin, J. E. Grove, L. Guillemot, S. Guiriec, G. Haller, A. K. Harding, P. A. Hart, R. C. Hartman, E. Hays, G. Hobbs, R. E. Hughes, G. Jóhannesson, A. S. Johnson, R. P. Johnson, T. J. Johnson, W. N. Johnson, S. Johnston, T. Kamae, G. Kanbach, V. M. Kaspi, H. Katagiri, Jun Kataoka, A. Kavelaars, N. Kawai, H. Kelly, M. Kerr, B. Kiziltan, W. Klamra, J. Knödlseder, M. Kramer, F. Kuehn, M. Kuss, J. Lande, D. Landriu, L. Latronico, B. Lee, S. H. Lee, M. Lemoine-Goumard, M. Livingstone, F. Longo, F. Loparco, B. Lott, M. N. Lovellette, P. Lubrano, A. G. Lyne, G. M. Madejski, A. Makeev, R. N. Manchester, B. Marangelli, M. Marelli, M. N. Mazziotta, J. E. McEnery, S. McGlynn, M. A. McLaughlin, N. Menon, C. Meurer, P. F. Michelson, T. Mineo, N. Mirizzi, W. Mitthumsiri, T. Mizuno, A. A. Moiseev, M. Mongelli, C. Monte, M. E. Monzani, E. Moretti, A. Morselli, I. V. Moskalenko, S. Murgia, T. Nakamori, P. L. Nolan, A. Noutsos, E. Nuss, T. Ohsugi, N. Omodei, E. Orlando, J. F. Ormes, M. Ozaki, A. Paccagnella, D. Paneque, J. H. Panetta, D. Parent, M. Pearce, M. Pepe, M. Perchiazzi, M. Pesce-Rollins, L. Pieri, M. Pinchera, F. Piron, T. A. Porter, S. Rainò, R. Rando, S. M. Ransom, E. Rapposelli, M. Razzano, A. Reimer, O. Reimer, T. Reposeur, L. C. Reyes, S. Ritz, L. S. Rochester, A. Y. Rodriguez, R. W. Romani, M. Roth, F. Ryde, A. Sacchetti, H. F W Sadrozinski, N. Saggini, D. Sanchez, A. Sander, P. M Saz Parkinson, K. N. Segal, A. Sellerholm, C. Sgrò, E. J. Siskind, D. A. Smith, P. D. Smith, G. Spandre, P. Spinelli, M. Stamatikos, J. L. Starck, F. W. Stecker, T. E. Stephens, M. S. Strickman, A. W. Strong, D. J. Suson, H. Tajima, H. Takahashi, T. Takahashi, T. Tanaka, A. Tenze, J. B. Thayer, J. G. Thayer, G. Theureau, D. J. Thompson, S. E. Thorsett, L. Tibaldo, O. Tibolla, D. F. Torres, A. Tramacere, M. Turri, T. L. Usher, L. Vigiani, N. Vilchez, V. Vitale, A. P. Waite, P. Wang, K. Watters, P. Weltevrede, B. L. Winer, K. S. Wood, T. Ylinen, M. Ziegler

Research output: Contribution to journalArticle

123 Citations (Scopus)

Abstract

The Vela pulsar is the brightest persistent source in the GeV sky and thus is the traditional first target for new γ-ray observatories. We report here on initial Fermi Large Area Telescope observations during verification phase pointed exposure and early sky survey scanning. We have used the Vela signal to verify Fermi timing and angular resolution. The high-quality pulse profile, with some 32,400 pulsed photons at E ≥ 0.03GeV, shows new features, including pulse structure as fine as 0.3ms and a distinct third peak, which shifts in phase with energy. We examine the high-energy behavior of the pulsed emission; initial spectra suggest a phase-averaged power-law index of Γ = 1.51+0.05 -0.04 with an exponential cutoff at E c = 2.9 ± 0.1 GeV. Spectral fits with generalized cutoffs of the form require b ≤ 1, which is inconsistent with magnetic pair attenuation, and thus favor outer-magnetosphere emission models. Finally, we report on upper limits to any unpulsed component, as might be associated with a surrounding pulsar wind nebula.

Original languageEnglish
Pages (from-to)1084-1093
Number of pages10
JournalAstrophysical Journal
Volume696
Issue number2
DOIs
Publication statusPublished - 2009 May 10
Externally publishedYes

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Keywords

  • gamma rays: observations
  • pulsars: individual (PSR B0833-45)

ASJC Scopus subject areas

  • Space and Planetary Science
  • Astronomy and Astrophysics

Cite this

Abdo, A. A., Ackermann, M., Atwood, W. B., Bagagli, R., Baldini, L., Ballet, J., Band, D. L., Barbiellini, G., Baring, M. G., Bartelt, J., Bastieri, D., Baughman, B. M., Bechtol, K., Bellardi, F., Bellazzini, R., Berenji, B., Bisello, D., Blandford, R. D., Bloom, E. D., ... Ziegler, M. (2009). Fermi large area telescope observations of the vela pulsar. Astrophysical Journal, 696(2), 1084-1093. https://doi.org/10.1088/0004-637X/696/2/1084