Two Radio-Emission Mechanisms in PSR J0901–4624

Abstract

We have detected sporadic, bright, short-duration radio pulses from PSR J0901−4624. These pulses are emitted simultaneously with persistent, periodic emission that dominates the flux density when averaging over many periods of the pulsar. The bright pulses have energies that are consistent with a power-law distribution. The integrated profile of PSR J0901−4624 is highly polarized and shows four distinct components. The bright pulses appear to originate near the magnetic pole of the pulsar and have polarization properties unlike that of the underlying emission at the same pulse phase. We conclude that the bright pulses represent a secondary giant-micropulse emission process, possibly from a different region in the pulsar magnetosphere.

Dual-frequency single-pulse study of PSR B0950+08

“…While there has been some progress in constraining single-pulse fluence distributions on a population level (Burke-Spolaor et al 2012;Mickaliger et al 2018) since the 1970s, much of the field is still there to explore. At the same time a plethora of peculiar single-pulse variability patterns has been discovered, including, but not limited to giant micropulses (µs-wide, F > 10F AP for longitude-resolved fluence only, PL energy distribution with indices similar to those of GPs, see Johnston & Romani 2002;Cairns et al 2004;Raithel et al 2015); individual pulses from sparsely radio-emitting neutron stars ("rotating radio transients", RRATs McLaughlin et al 2006), which are wider than GPs and have a lognormal fluence distribution (Keane et al 2010;Mickaliger et al 2018); RRATlike pulses from normal pulsars (e.g., Esamdin et al 2012), "bursting modes" characterized by abrupt onset, changes in the shape of the single-pulse fluence distribution and the shape of the average profile (e.g., Seymour et al 2014;Wang et al 2020); prolonged periods of absence of any emission (nulling, resulting in very low values of average flux, see, for example, Gajjar et al 2014). At low radio frequencies of 100 MHz single-pulse fluences seem to be more variable, resulting in regular detection of ms-wide pulses above the 10F AP GP threshold (Kuzmin 2007;Ulyanov et al 2006).…”

The two emission states of PSR B1534+12

“…A similar phenomenon is the giant micro-pulses, in which the flux density is significantly greater than typical value at specific pulse phases, but the overall integrated flux density of the profile remains approximately constant (Kramer et al 2002). This phenomenon has been detected in some young pulsars, such as the Vela pulsar (Kramer et al 2002), PSR B1706−44 (Johnston & Romani 2002) and PSR J0901−4624 (Raithel et al 2015). The energy density of these micro-pulses also follow a power-law distribution.…”

Dual-frequency single-pulse study of PSR B0950+08

“…While there has been some progress in constraining singlepulse fluence distributions on a population level (Burke-Spolaor et al 2012;Mickaliger et al 2018) since the 1970s, much of the field is still there to explore. At the same time a plethora of peculiar single-pulse variability patterns has been discovered, including, but not limited to giant micropulses (µs-wide, F > 10F AP for longitude-resolved fluence only, PL energy distribution with indices similar to those of GPs, see Johnston & Romani 2002;Cairns et al 2004;Raithel et al 2015); individual pulses from sparsely radio-emitting neutron stars ("rotating radio transients", RRATs McLaughlin et al 2006), which are wider than GPs and have a lognormal fluence distribution (Keane et al 2010;Mick-7 A threshold 2× higher is also extensively used in the literature, and flux density integration methods varies: average fluence in the whole on-pulse window, in a given component, in a phase window of GPs, peak flux density and so on. aliger et al 2018); RRAT-like pulses from normal pulsars (e.g.…”