Show simple item record

dc.contributor.authorAbdo, A.A.
dc.contributor.authorVenter, C.
dc.contributor.authorAckermann, M.
dc.contributor.authorAjello, M.
dc.contributor.authorAllafort, A.
dc.contributor.authorFermi LAT
dc.date.accessioned2014-04-23T10:37:27Z
dc.date.available2014-04-23T10:37:27Z
dc.date.issued2010
dc.identifier.citationAbdo, A.A. et al. 2010. The Vela pulsar: results from the first year of Fermi LAT observations. Astrophysical journal, 713(1):154-165. [https://doi.org/10.1088/0004-637X/713/1/154]en_US
dc.identifier.issn0004-637X
dc.identifier.issn1538-4357 (Online)
dc.identifier.urihttp://hdl.handle.net/10394/10469
dc.identifier.urihttps://doi.org/10.1088/0004-637X/713/1/154
dc.identifier.urihttps://iopscience.iop.org/0004-637X/713/1/154/pdf/0004-637X_713_1_154.pdf
dc.description.abstractWe report on analysis of timing and spectroscopy of the Vela pulsar using 11 months of observations with the Large Area Telescope (LAT) on the Fermi Gamma-ray Space Telescope. The intrinsic brightness of Vela at GeV energies combined with the angular resolution and sensitivity of the LAT allows us to make the most detailed study to date of the energy-dependent light curves and phase-resolved spectra, using a LAT-derived timing model. The light curve consists of two peaks (P1 and P2) connected by bridge emission containing a third peak (P3). We have confirmed the strong decrease of the P1/P2 ratio with increasing energy seen with EGRET and previous Fermi LAT data, and observe that P1 disappears above 20 GeV. The increase with energy of the mean phase of the P3 component can be followed with much greater detail, showing that P3 and P2 are present up to the highest energies of pulsation. We find significant pulsed emission at phases outside the main profile, indicating that magnetospheric emission exists over 80% of the pulsar period. With increased high-energy counts the phase-averaged spectrum is seen to depart from a power law with simple exponential cutoff, and is better fit with a more gradual cutoff. The spectra in fixed-count phase bins are well fit with power laws with exponential cutoffs, revealing a strong and complex phase dependence of the cutoff energy, especially in the peaks. By combining these results with predictions of the outer magnetosphere models that map emission characteristics to phase, it will be possible to probe the particle acceleration and the structure of the pulsar magnetosphere with unprecedented detail.en_US
dc.language.isoenen_US
dc.publisherIOP Publishingen_US
dc.rights© 2010. The American Astronomical Society. All rights reserved.
dc.subjectPulsars: generalen_US
dc.subjectStars: neutronen_US
dc.titleThe Vela pulsar: results from the first year of Fermi LAT observationsen_US
dc.typeArticleen_US
dc.contributor.researchID12006653 - Venter, Christo


Files in this item

Thumbnail

This item appears in the following Collection(s)

Show simple item record