Astronomy and Astrophysics – Astrophysics – Solar and Stellar Astrophysics
Scientific paper
2010-06-02
Astronomy and Astrophysics
Astrophysics
Solar and Stellar Astrophysics
15 pages, 14 figures, and 4 tables; Trimmed abstract; Full abstract can be found in PS/PDF version; Accepted for publication i
Scientific paper
We report on the unique nulling properties of PSR B0818-41, using the GMRT at 325 and 610 MHz. We find following interesting behaviour just before and after the nulls: (i) The pulsar's intensity does not switch off abruptly at the null, but fades gradually, taking ~ 10 P1. Just after nulls intensity rises to a maximum over a short (less than one period) time scale. (ii) While the last active pulses before nulls are dimmer, the first few active pulses just after nulls outshine normal ones. This effect is very clear for inner region of pulsar profile, where mean intensity of last few active pulses just after nulls is ~ 2.8 times more than that for last active pulses just before nulls. (iii) There is a significant evolution of shape of the pulsar's profile, around nulls, especially at beginning of bursts: an enhanced bump of intensity in inner region, a change in ratio of strengths of the leading and trailing peaks towards a more symmetric profile, an increase in profile width of about 10%, and a shift of profile centre towards later longitudes. (iv) Just before nulls, the apparent drift rate becomes slower, transitioning to an almost phase stationary drift pattern. Further, when the pulsar comes out of null, the increased intensity is very often accompanied by what looks like a disturbed drift rate behaviour, which settles down to the regular drift pattern as the pulsar intensity returns to normal. Thus, we find some very specific and well correlated changes in the radio emission properties of PSR B0818-41 when the emission restarts after a null. These could imply that the phenomenon of nulling is associated with some kind of a "reset" of the pulsar radio emission engine. We also present plausible explanations for some of the observed behaviour, using the Partially Screened Gap model of the inner pulsar accelerator.
Bhattacharyya Bhaswati
Gil Janusz
Gupta Yashwant
No associations
LandOfFree
Investigation of the unique nulling properties of PSR B0818-41 does not yet have a rating. At this time, there are no reviews or comments for this scientific paper.
If you have personal experience with Investigation of the unique nulling properties of PSR B0818-41, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Investigation of the unique nulling properties of PSR B0818-41 will most certainly appreciate the feedback.
Profile ID: LFWR-SCP-O-512837