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American Astronomical Society, Astrophysical Journal, 1(705), p. 1-13, 2009

DOI: 10.1088/0004-637x/705/1/1

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Radio Detection of LAT PSRs J1741-2054 and J2032+4127: No Longer Just Gamma-ray Pulsars

This paper is made freely available by the publisher.
This paper is made freely available by the publisher.

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Red circle
Preprint: archiving forbidden
Red circle
Postprint: archiving forbidden
Green circle
Published version: archiving allowed
Data provided by SHERPA/RoMEO

Abstract

Sixteen pulsars have been discovered so far in blind searches of photonscollected with the Large Area Telescope on the Fermi Gamma-ray SpaceTelescope. We here report the discovery of radio pulsations from two ofthem. PSR J1741-2054, with period P = 413 ms, was detected in archivalParkes telescope data and subsequently has been detected at the GreenBank Telescope (GBT). Its received flux varies greatly due tointerstellar scintillation and it has a very small dispersion measure ofDM = 4.7 pc cm$^{-3}$, implying a distance of {\ap}0.4 kpc andpossibly the smallest luminosity of any known radio pulsar. At thisdistance, for isotropic emission, its gamma-ray luminosity above 0.1 GeVcorresponds to 28\% of the spin-down luminosity of $\backslash$dot$\{$E$\}$ = 9.4{\times}10\^{}$\{$33$\}$ erg s$^{-1}$. The gamma-ray profile occupies 1/3 of pulsephase and has three closely spaced peaks with the first peak lagging theradio pulse by {$δ$} = 0.29 P. We have also identified a soft Swiftsource that is the likely X-ray counterpart. In many respects PSRJ1741-2054 resembles the Geminga pulsar. The second source, PSRJ2032+4127, was detected at the GBT. It has P = 143 ms, and its DM = 115pc cm$^{-3}$ suggests a distance of {\ap}3.6 kpc, but we considerit likely that it is located within the Cyg OB2 stellar association athalf that distance. The radio emission is nearly 100\% linearlypolarized, and the main radio peak precedes by {$δ$} = 0.15 P thefirst of two narrow gamma-ray peaks that are separated by {$Δ$} = 0.50P. The second peak has a harder spectrum than the first one, following atrend observed in young gamma-ray pulsars. Faint, diffuse X-ray emissionin a Chandra image is possibly its pulsar wind nebula. The wind of PSRJ2032+4127 is responsible for the formerly unidentified HEGRA source TeVJ2032+4130. PSR J2032+4127 is coincident in projection with MT91 213, aBe star in Cyg OB2, although apparently not a binary companion of it.