Pulsed Gamma-Rays from PSR J2021+3651 with the Fermi Large Area Telescope
In this paper, we report the detection of pulsed gamma-rays from the young, spin-powered radio pulsar PSR J2021+3651 using data acquired with the Large Area Telescope (LAT) on the Fermi Gamma-ray Space Telescope (formerly GLAST). The light curve consists of two narrow peaks of similar amplitude separated by 0.468 ± 0.002 in phase. The first peak lags the maximum of the 2 GHz radio pulse by 0.162 ± 0.004 ± 0.01 in phase. The integral gamma-ray photon flux above 100 MeV is (56 ± 3 ± 11) × 10–8 cm–2 s–1. The photon spectrum is well described by an exponentially cut-off power law of the form dF/dE = kE–Γe(–E/Ec), where the energy E is expressed in GeV. The photon index is Γ = 1.5 ± 0.1 ± 0.1 and the exponential cut-off is Ec = 2.4 ± 0.3 ± 0.5 GeV. The first uncertainty is statistical and the second is systematic. The integral photon flux of the bridge is approximately 10% of the pulsed emission, and the upper limit on off-pulse gamma-ray emission from a putative pulsar wind nebula is < 10% of the pulsed emission at the 95% confidence level. Radio polarization measurements yield a rotation measure of RM = 524 ± 4 rad m–2 but a poorly constrained magnetic geometry. Re-analysis of Chandra X-ray Observatory data enhanced the significance of the weak X-ray pulsations, and the first peak is roughly phase aligned with the first gamma-ray peak. We discuss the emission region and beaming geometry based on the shape and spectrum of the gamma-ray light curve combined with radio and X-ray measurements, and the implications for the pulsar distance. Finally, gamma-ray emission from the polar cap region seems unlikely for this pulsar.
- Research Organization:
- SLAC National Accelerator Laboratory (SLAC), Menlo Park, CA (United States)
- Sponsoring Organization:
- USDOE
- Contributing Organization:
- Fermi LAT Collaboration
- Grant/Contract Number:
- AC02-76SF00515
- OSTI ID:
- 1357440
- Journal Information:
- The Astrophysical Journal, Vol. 700, Issue 2; ISSN 0004-637X
- Publisher:
- Institute of Physics (IOP)Copyright Statement
- Country of Publication:
- United States
- Language:
- English
Web of Science
THE SECOND FERMI LARGE AREA TELESCOPE CATALOG OF GAMMA-RAY PULSARS
|
journal | September 2013 |
Prospects for the detection of high-energy (E > 25 GeV) Fermi pulsars with the Cherenkov Telescope Array
|
journal | June 2017 |
The Second Fermi Large area Telescope Catalog of Gamma-Ray Pulsars
|
text | January 2013 |
X-ray and Radio Timing of the Pulsar in 3C 58 | text | January 2009 |
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