97 research outputs found
Evolution of Multipolar Magnetic Fields in Isolated Neutron Stars and its effect on Pulsar Radio Emission
The evolution of the multipolar structure of the magnetic field of isolated
neutron stars is studied assuming the currents to be confined to the crust.
Lower orders () of multipole are seen to evolve in a manner similar to
the dipole suggesting little or no evolution of the expected pulse shape. We
also study the multifrequency polarization position angle traverse of PSR
B0329+54 and find a significant frequency dependence above 2.7 GHz. We
interpret this as an evidence of strong multipolar magnetic field present in
the radio emission region.Comment: 2 pages, 2 figures, uses newpasp.sty, to appear in ASP Conf. Series,
IAU Coll. 177 on Pulsar Astronomy-2000 and Beyond, ed. M. Kramer, N. Wex, R.
Wielebinsk
The Effelsberg Search for Pulsars in the Galactic Centre
We report the status of a search for pulsars in the Galactic Centre, using acompletely revised and improved high-sensitivity double-horn system at4.85-GHz. We also present calculations about the success rate of periodicitysearches for such a survey, showing that in contrast to conclusions in recentliterature pulsars can be indeed detected at the chosen search frequency
Prospects for multiwavelength polarization observations of GRB afterglows and the case GRB 030329
We explore the prospects for simultaneous, broad-band, multiwavelength
polarimetric observations of GRB afterglows. We focus on the role of cosmic
dust in GRB host galaxies on the observed percentage polarization of afterglows
in the optical/near-infrared bands as a function of redshift. Our driving point
is the afterglow of GRB 030329, for which we obtained polarimetric data in the
R band and K band simultaneously about 1.5 days after the burst. We argue that
polarimetric observations can be very sensitive to dust in a GRB host, because
dust can render the polarization of an afterglow wavelength-dependent. We
discuss the consequences for the interpretation of observational data and
emphasize the important role of very early polarimetric follow-up observations
in all bands, when afterglows are still bright, to study the physical
properties of dust and magnetic fields in high-z galaxies.Comment: accepted for publication in Astronomy & Astrophysic
A flexible format for exchanging pulsar data
We describe a data format currently in use amongst European institutions for exchanging and archiving pulsar data. The format is designed to be as flexible as possible with regard to present and future compatibility with different operating systems. One application of the common format is simultaneous multi-frequency observations of single pulses. A data archive containing over 2500 pulse profiles stored in this format is now available via the Internet (see http://www.mpifr-bonn.mpg.de/pulsar/data), together with a small suite of computer programs that can read, write and display the data
Simultaneous single-pulse observations of radio pulsars: I. The polarization characteristics of PSR B0329+54
We present the first results from a programme of multi-frequency simultaneous
single pulse observations carried out as part of the European Pulsar Network.
We detail the main data analysis methods and apply them to simultaneous
observations of the strong pulsar B0329+54 at 1.4 and 2.7 GHz using the Jodrell
Bank and Effelsberg radio telescopes respectively. The pulses at different
frequencies are highly correlated in their total intensity, as seen in previous
experiments, and generally show consistent position angles of the linearly
polarized component. In contrast, the circularly polarized emission sometimes
shows clear differences between pulses received at different frequencies. These
results are unexpected and warrant further follow-up studies to interpret them
in the context of the intrinsic bandwidth of pulsar radiation.Comment: To be published in A&A. 8 pages, 7 figure
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