1,226 research outputs found
Multiwavelength Studies of PSR J1420-6048, a Young Pulsar in the Kookaburra
We present X-ray, radio, and infrared observations of the 68 ms pulsar PSR
J1420-6048 and its surrounding nebula, a possible counterpart of the gamma-ray
source GeV J1417-6100/3EG J1420-6038. Pulsed X-ray emission at the radio period
is marginally detected by ASCA from a source embedded in the hard spectrum
X-ray nebula AX J1420.1-6049. At radio wavelengths, the pulsar is found to be
strongly linearly and circularly polarized, and the polarization sweep is
measured. A comparison of high resolution ATCA radio imaging of the
Kookaburra's upper wing (G313.6+0.3), which contains the pulsar and the X-ray
nebula, with infrared images suggests the radio emission is partly non-thermal.Comment: 8 pages, 4 figures, to appear in Astrophysical Journal Letter
Pulsar Wind Nebulae in EGRET Error Boxes
A remarkable number of pulsar wind nebulae (PWN) are coincident with EGRET
gamma-ray sources. X-ray and radio imaging studies of unidentified EGRET
sources have resulted in the discovery of at least 6 new pulsar wind nebulae
(PWN). Stationary PWN (SPWN) appear to be associated with steady EGRET sources
with hard spectra, typical for gamma-ray pulsars. Their toroidal morphologies
can help determine the geometry of the pulsar which is useful for constraining
models of pulsed gamma-ray emission. Rapidly moving PWN (RPWN) with more
cometary morphologies seem to be associated with variable EGRET sources in
regions where the ambient medium is dense compared to what is typical for the
ISM.Comment: 8 pages, 5 figures, to appear in the proceedings of "The
Multiwavelength Approach to Unidentified Sources", ed. G. Romero & K.S. Chen
Chandra Imaging of the Gamma-Ray Source GeV J1809-2327
We report on Chandra imaging observations of the Galactic Unidentified
-ray source GEV J1809-2327, comparing the X-ray images with new VLA
1.46 GHz and 4.86 GHz maps. The X-ray images reveal a point source connected to
a non-thermal X-ray/radio nebula, supporting a pulsar/wind model for the
-ray emitter. We also detect numerous X-ray sources from the young
stellar association in the adjacent HII region S32.Comment: to appear in ApJ letter
The Full Spectrum Galactic Terrarium: MHz to TeV Observations of Various Critters
Multi-wavelength studies at radio, infrared, optical, X-ray, and TeV
wavelengths have discovered probable counterparts to many Galactic sources of
GeV emission detected by EGRET. These include pulsar wind nebulae, high mass
X-ray binaries, and mixed morphology supernova remnants. Here we provide an
overview of the observational properties of Galactic sources which emit across
19 orders of magnitude in energy. We also present new observations of several
sources.Comment: 4 pages, 5 figures, Proceedings of the The 4th Heidelberg
International Symposium on High Energy Gamma-Ray Astronomy, eds. Aharonian,
Hofmann, Riege
Runaway Massive Binaries and Cluster Ejection Scenarios
The production of runaway massive binaries offers key insights into the
evolution of close binary stars and open clusters. The stars HD 14633 and HD
15137 are rare examples of such runaway systems, and in this work we
investigate the mechanism by which they were ejected from their parent open
cluster, NGC 654. We discuss observational characteristics that can be used to
distinguish supernova ejected systems from those ejected by dynamical
interactions, and we present the results of a new radio pulsar search of these
systems as well as estimates of their predicted X-ray flux assuming that each
binary contains a compact object. Since neither pulsars nor X-ray emission are
observed in these systems, we cannot conclude that these binaries contain
compact companions. We also consider whether they may have been ejected by
dynamical interactions in the dense environment where they formed, and our
simulations of four-body interactions suggest that a dynamical origin is
possible but unlikely. We recommend further X-ray observations that will
conclusively identify whether HD 14633 or HD 15137 contain neutron stars.Comment: Accepted to ApJ, 11 page
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