Discovery of two millisecond pulsars in Fermi sources with the Nancay Radio Telescope

Ismaël Cognard (1, 2) , Lucas Guillemot (3) , T. J. Johnson (4) , D. A. Smith (5) , C. Venter (6) , A. K. Harding (4) , M. T. Wolff (7) , C. C. Cheung (8) , D. Donato (9) , A.A. Abdo (8) , Jean Ballet (10) , F. Camilo (11) , G. Desvignes (12) , D. Dumora (5) , E. C. Ferrara (4) , P. C. C. Freire (3) , J. E. Grove (7) , S. Johnston (13) , M. Keith (13) , M. Kramer (3) , A. G. Lyne (14) , P. F. Michelson (15) , D. Parent (16) , S. M. Ransom (17) , P. S. Ray (7) , R. W. Romani (15) , P. M. Saz Parkinson (18) , B. W. Stappers (14) , Gilles Theureau (2, 1) , D. J. Thompson (4) , P. Weltevrede (14) , K. S. Wood (7)

1 USN - Unité Scientifique de la Station de Nançay
2 LPCE - Laboratoire de physique et chimie de l'environnement
3 MPIFR - Max-Planck-Institut für Radioastronomie
4 GSFC - NASA Goddard Space Flight Center
5 CENBG - Centre d'Etudes Nucléaires de Bordeaux Gradignan
6 NWU - North-West University [South Aftrica]
7 Space Science Division [Washington]
8 National Research Council Washington
9 CRESST - Center for Research and Exploration in Space Science and Technology [GSFC]
10 AIM (UMR7158 / UMR_E_9005 / UM_112) - Astrophysique Interprétation Modélisation
11 CAL - Columbia Astrophysics Laboratory
12 RAL - Berkeley Radio Astronomy Laboratory
13 ATNF - Australia Telescope National Facility
14 Jodrell Bank Centre for Astrophysics
15 HEPL - W. W. Hansen Experimental Physics Laboratory
16 George Mason University [Fairfax]
17 NRAO - National Radio Astronomy Observatory [Socorro]
18 Santa Cruz Institute for Particle Physics

We report the discovery of two millisecond pulsars in a search for radio pulsations at the positions of \emph{Fermi Large Area Telescope} sources with no previously known counterparts, using the Nançay radio telescope. The two millisecond pulsars, PSRs J2017+0603 and J2302+4442, have rotational periods of 2.896 and 5.192 ms and are both in binary systems with low-eccentricity orbits and orbital periods of 2.2 and 125.9 days respectively, suggesting long recycling processes. Gamma-ray pulsations were subsequently detected for both objects, indicating that they power the associated \emph{Fermi} sources in which they were found. The gamma-ray light curves and spectral properties are similar to those of previously-detected gamma-ray millisecond pulsars. Detailed modeling of the observed radio and gamma-ray light curves shows that the gamma-ray emission seems to originate at high altitudes in their magnetospheres. Additionally, X-ray observations revealed the presence of an X-ray source at the position of PSR J2302+4442, consistent with thermal emission from a neutron star. These discoveries along with the numerous detections of radio-loud millisecond pulsars in gamma rays suggest that many \emph{Fermi} sources with no known counterpart could be unknown millisecond pulsars.

Mots clés: J2302+4442); gamma rays: general; pulsars: general; pulsars: individual (J2017+0603

Domaines: Phénomènes cosmiques de haute energie [astro-ph.HE]; Phénomènes cosmiques de haute energie [astro-ph.HE]

Ismaël Cognard, Lucas Guillemot, T. J. Johnson, D. A. Smith, C. Venter, et al.. Discovery of two millisecond pulsars in Fermi sources with the Nancay Radio Telescope. The Astrophysical Journal, 2011, 732, 47 (11 p.). ⟨10.1088/0004-637X/732/1/47⟩. ⟨in2p3-00605514⟩