* Astronomy

Blobrana · L

Accreting millisecond X-ray pulsars

Blobrana · L

RE: Millisecond Pulsars

Blobrana · L

Title: Deriving fundamental parameters of millisecond pulsars via AIC in white dwarfs
Authors: A. Taani, C.M. Zhang, Y.H. Zhao, A. Moraghan

We present a study of the observational properties of Millisecond Pulsars (MSPs) by way of their magnetic fields, spin periods and masses. These measurements are derived through the scenario of Accretion Induced Collapse (AIC) of white dwarfs (WDs) in stellar binary systems, in order to provide a greater understanding of the characteristics of MSP populations. In addition, we demonstrate a strong evolutionary connection between neutron stars and WDs with binary companions from a stellar binary evolution perspective via the AIC process.

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A New Way to Discover Pulsars

A team led by postdoctoral researcher Matthew Kerr of the Kavli Institute for Particle Astrophysics and Cosmology (KIPAC), and Columbia University radio astronomer Fernando Camilo is reporting the use of new techniques for hunting pulsars. They and their colleagues have found a way to look for likely pulsar candidates by combining observations from the LAT and the Parkes radio telescope in Australia. This approach combines the broad reach of an all-sky telescope (the LAT) with the deep sensitivity of a radio telescope, which can view only a tiny part of the sky at a time.
So far, the discovery of five more rapidly rotating, or "millisecond" pulsars, including one particularly intriguing object, prove that the technique is successful and likely to uncover many more pulsars in our galaxy. One especially interesting object discovered with this technique seems to have a previously unknown waveform - a gamma-ray peak before and after each radio peak - an effect the team could not explain using standard models of pulsar geometry. This suggests that the radio part of the beam may originate at two distinct points above the object's surface. This variation increases the mystery and allure of these fascinating astrophysical phenomena.
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Title: Five New Millisecond Pulsars From a Radio Survey of 14 Unidentified Fermi-LAT Gamma-ray Sources
Authors: M. Kerr, F. Camilo, T. J. Johnson, E. C. Ferrara, L. Guillemot, A. K. Harding, J. Hessels, S. Johnston, M. Keith, M. Kramer, S. M. Ransom, P. S. Ray, J. E. Reynolds, J. Sarkissian, K. S. Wood

We have discovered five millisecond pulsars (MSPs) in a survey of 14 unidentified Fermi-LAT sources in the southern sky using the Parkes radio telescope. PSRs J0101-6422, J1514-4946, and J1902-5105 reside in binaries, while PSRs J1658-5324 and J1747-4036 are isolated. Using an ephemeris derived from timing observations of PSR J0101-6422 (P =2.57 ms, DM=12 pc cm^-3), we have detected gamma-ray pulsations and measured its proper motion. Its gamma-ray spectrum (a power law of Gamma = 0.9 with a cutoff at 1.6 GeV) and efficiency are typical of other MSPs, but its radio and gamma-ray light curves challenge simple geometric models of emission. The high success rate of this survey-enabled by selecting gamma-ray sources based on their detailed spectral characteristics-and other similarly successful searches indicate that a substantial fraction of the local population of MSPs may soon be known.

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