Abstract Details
| Name: Sushan Konar Affiliation: NCRA-TIFR Conference ID: ASI2018_612 Title : The Nulling Pulsars : A statistical study Authors and Co-Authors : Uddeepta Deka, Department of Physics & Astrophysics, University of Delhi Abstract Type : Contributed Talk Abstract Category : Stars,ISM and the Galaxy Abstract : Radio pulsars are strongly magnetized rotating neutron stars and are characterized by their short spin periods ($P \sim 10^{-3} - 10^2$~s) and large inferred surface magnetic fields ($B \sim 10^8 - 10^{15}$~G). Abrupt cessation of their pulsed radio emission for several pulse periods, observed in some hundred odd pulsars, is known as the phenomenon of nulling. The nature and degree of this nulling varies from pulsar to pulsar. Detailed investigations of the nulling behaviour of individual pulsars and theoretical modeling of the phenomenon have been undertaken by many individuals/groups. However, except for some of the pioneering studies (Rankin 1986; Biggs 19992; Wang, Manchester & Johnston 2007) comprehensive statistical study of nulling has not been given a lot of attention. In view of the existing data it is now possible to find the statistical characteristics of the population of nulling pulsars. We investigate this. In the analysis, we also include the intermittent pulsars and the rotating radio transients (RRAT). Recently, it has been suggested that there may exist a trend for nulling activity, going from ordinary nulling pulsars to intermittents to RRATs. Here we try to quantify the nulling behaviour to check for any difference between these different classes of pulsars. With that aim we find the proximity of a given object to the death-line. We quantify this proximity by a parameter $q_d$ such that, $q_d = \tau_d / \tau_c$. Here $\tau_d$ is the time left for a pulsar to reach the death line assuming its magnetic field to remain constant at the present value. And $\tau_c$ is the characteristic age of a pulsar given by $P/\dot{P}$. Evidently, the value of $\tau_d$ depends on the choice of a particular death-line. We find that for any assumed death-line the statistical distribution of $q_d$ for ordinary nulling pulsars is very different from that of the RRATs. References : 1. Biggs J. D., 1992, ApJ, 394, 574 3. Rankin J., 1986, ApJ, 301, 901 4. Wang N., Manchester R. N., Johnston S., 2007, MNRAS, 377, 1383 |