Deep analyses of nulling in Arecibo pulsars reveal further periodic behaviour

Abstract

Numerous studies of conal pulsars, e.g. B1133+16, have revealed fluctuation features and a steady null fraction. Sensitive Arecibo observations provide an unprecedented ability to detect nulls and confirm previously found fluctuation features. By replacing each pulse with a scaled version of the average profile, we were able to quench all subpulse modulation, dubbed pulse‐modulation quelling (PMQ). It was surprising to note that the low‐frequency feature observed in the natural longitude resolved fluctuation spectra (LRF) persisted in the PMQ LRFs. It appears that we can conclude, then, that in the natural pulse sequence the nulls themselves reflect whatever underlying periodicity is responsible for the low‐frequency feature. Conversely, the aggregate fluctuation power of the low‐frequency feature changes little whether the pulse modulation is quelled or not, implying that the feature fluctuations are produced by the nulls!

Meterwavelength Single-pulse Polarimetric Emission Survey. III. The Phenomenon of Nulling in Pulsars

“…Nulling is reported to be mainly seen in the Q mode. The PMQ analysis of Herfindal & Rankin (2009) showed the presence of low frequency structure which is verified in our nulling periodicity studies.…”

“…The periodic nulling in the carousel model are associated with conal components (Herfindal & Rankin 2009) and provide an immediate prediction that these should not be manifested in the stationary core components. To test this prediction we have collected the nineteen pulsars with reported nulling periodicity in table 3 along with their profile classification.…”

“…The LRFS of this pulsar show two feature, one associated with drifting with P 3 roughly 6 P and another corresponding to nulling at 103±34 P . Herfindal & Rankin (2009) also identified the low frequency feature in their PMQ analysis. Interestingly Young & Rankin (2012) showed that the bridge emission between the conal components has a hidden core emission.…”

CORRELATION OFFERMIPHOTONS WITH HIGH-FREQUENCY RADIO GIANT PULSES FROM THE CRAB PULSAR

“…Similar to other sporadic variability phenomena seen in pulsar radio emission, represented by nulling pulsars (e.g., Herfindal & Rankin 2009), intermittent pulsars (Kramer et al 2006), and rotating radio transients (McLaughlin et al 2006), GP emission could be due to changes in the coherence of the radio emission, variations in the pair creation rate in the magnetosphere, or changes in the beaming direction. If the GP phenomenon is due to changes in the coherence of the radio emission mechanism, then one would expect little correlation of the radio GPs with the high-energy emission.…”

On the randomness of pulsar nulls

“…In an earlier study, Redman, Wright & Rankin (2005) showed that the nulls of B2303+30 occurred exclusively during one of the pulsar's two emission modes, which were distinguishable via the subpulse drift rate. The nulls of both B0834+06 and J1819+1305 were shown to exhibit periodicities related to the subpulse modulation (Rankin & Wright 2007, 2008); and fluctuation features produced by null periodicities have now been identified in a number of pulsars (Herfindal & Rankin 2007, 2009). The implication of these results, apparently, is that many nulls are the result of ‘empty’ sightline traverses through a rotating ‘carousel’ of emitting subbeams (Deshpande & Rankin 2001).…”