Multifrequency behaviour of the anomalous events of PSR J0922+0638

Shaifullah, G.; Tiburzi, C.; Osłowski, S.; Verbiest, J. P. W.; Szary, Andrzej; Künsemöller, Jörn; Horneffer, A.; Anderson, J. M.; Krämer, M.; Schwarz, Dominik J.; Mann, G.; Steinmetz, Matthias; Vocks, C.

doi:10.1093/mnrasl/sly049

Cited by 6 publications

(17 citation statements)

References 32 publications

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“…Given the fact that the observations in ref. [17] have a limited time resolution (10 s), it is still possible that our dimmed pulses are in fact the same phenomenon. This, however, needs to be investigated with further observations.…”

Section: Discussionmentioning

confidence: 99%

“…Ref. [17] claimed support for the absorption model, although they noted that the absorption needs to have frequency-dependent efficiency to explain the pseudonulling phenomenon that only occurs at 150 MHz. However, since we have found that the pseudo-nulling phenomenon occurs over a wide frequency range, there is no longer a need for proving such a dependence.…”

Section: Discussionmentioning

confidence: 99%

“…Ref. [17] observed PSR B0919+06 by simultaneously using the Effelsberg 100-m telescope at 1350 MHz and the Bornim station of the LOw Frequency ARray (LOFAR) at 150 MHz. They detected seven abnormal events in their 1350 MHz observations, but they observed no emission shift at 150 MHz.…”

Section: Introductionmentioning

confidence: 99%

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FAST ultra-wideband observation of abnormal emission-shift events of PSR B0919+06

Peng

et al. 2019

Sci. China Phys. Mech. Astron.

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PSR B0919+06 is known for its abnormal emission phenomenon, where the pulse emission window occasionally shifts progressively in longitude and returns afterwards. The physical mechanism behind this phenomenon is still under investigation. In this paper, we present our ultra-wideband observation of this pulsar using the Five-hundred-meter Aperture Spherical radio Telescope (FAST), with simultaneous measurements in the frequency ranges 280-780 MHz and 1250-1550 MHz. We have identified three abnormal events, each of which becomes less apparent as the frequency decreases. At 1400 MHz, the averaged profile slightly shifted after the first and third abnormal events, implying a relationship between abnormal event and profile variation. We also found a linear trend in the left-edge position of the averaged profiles between the first and third event as well as after the third event, suggesting the existence of a slow-drifting mode between the two major events. The second event has a comparatively small shift in phase and is thus categorized as a "small flare state". During the third event, a sequence of approximately nine pulses was seen to significantly weaken in all frequency bands, likely associated with the pseudo-nulling observed at 150 MHz. A three-component de-composition analysis of the normal averaged profiles shows that the trailing component is dominant at our observing frequencies, while the centre component has a comparatively steeper spectrum. We found the overall flux density in an abnormal event to slightly differ from that in an ordinary state, and the difference shows a frequency dependence. A comparison of the normal, abnormal and dimmed averaged profile indicates that the leading component is likely to be stable in all states. Pulsar; B0919+06; Radio PACS number(s): 95.55.Jz, 95.85.Bh, 97.60.Gb Citation: Y.-Z. Yu, B. Peng, K. Liu, et al, FAST ultra-wideband observation of abnormal emission-shift events of PSR B0919+06, Sci. China-Phys. Mech. Astron. 62, 959504 (2019), doi: xxx

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Section: Discussionmentioning

confidence: 99%

Section: Discussionmentioning

confidence: 99%

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FAST ultra-wideband observation of abnormal emission-shift events of PSR B0919+06

Peng

et al. 2019

Sci. China Phys. Mech. Astron.

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“…The continuing pulsar monitoring campaign observes more than 100 pulsars weekly in the high band (Michilli et al 2018, Shaifullah et al 2018, Porayko et al 2019, Donner et al 2019). The signal is digitised at the station and channelised by a polyphase filterbank into 195 kHz-wide subbands.…”

Section: Observationsmentioning

confidence: 99%

On the usefulness of existing solar wind models for pulsar timing corrections

Tiburzi

Verbiest

Shaifullah

et al. 2019

Monthly Notices of the Royal Astronomical Society

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Dispersive delays due to the Solar wind introduce excess noise in high-precision pulsar timing experiments, and must be removed in order to achieve the accuracy needed to detect, e.g., low-frequency gravitational waves. In current pulsar timing experiments, this delay is usually removed by approximating the electron density distribution in the Solar wind either as spherically symmetric, or with a two-phase model that describes the contributions from both high-and low-speed phases of the Solar wind. However, no dataset has previously been available to test the performance and limitations of these models over extended timescales and with sufficient sensitivity. Here we present the results of such a test with an optimal dataset of observations of pulsar J0034−0534, taken with the German stations of LOFAR. We conclude that the spherical approximation performs systematically better than the two-phase model at almost all angular distances, with a residual root-mean-square (rms) given by the two-phase model being up to 28% larger than the result obtained with the spherical approximation. Nevertheless, the spherical approximation remains insufficiently accurate in modelling the Solar-wind delay (especially within 20 degrees of angular distance from the Sun), as it leaves timing residuals with rms values that reach the equivalent of 0.3 µs at 1400 MHz. This is because a spherical model ignores the large daily variations in electron density observed in the Solar wind. In the short term, broadband observations or simultaneous observations at low frequencies are the most promising way forward to correct for Solar-wind induced delay variations.

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“…These have been given different names in the literature, but we will use 'swooshes' (Rankin et al 2006a) in this paper. PSRs B0919+06 and B1859+07 show this behaviour and have been studied in great detail over the last decade (Rankin et al 2006a;Wahl et al 2016;Shaifullah et al 2018;Han et al 2016). Wahl et al (2016) performed a detailed analysis of the swooshes at multiple frequencies to show that the swooshes seen in PSR B1859+07 are quasi-periodic in nature.…”

Section: Introductionmentioning

confidence: 99%

Multi-frequency study of the peculiar pulsars PSR B0919+06 and PSR B1859+07

Rajwade,

Perera,

Stappers

et al. 2021

Preprint

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Since their discovery more than 50 years ago, broadband radio studies of pulsars have generated a wealth of information about the underlying physics of radio emission. In order to gain some further insights into this elusive emission mechanism, we performed a multi-frequency study of two very well-known pulsars, PSR B0919+06 and PSR B1859+07. These pulsars show peculiar radio emission properties whereby the emission shifts to an earlier rotation phase before returning to the nominal emission phase in a few tens of pulsar rotations (also known as 'swooshes'). We confirm the previous claim that the emission during the swoosh is not necessarily absent at low frequencies and the single pulses during a swoosh show varied behaviour at 220 MHz. We also confirm that in PSR B0919+06, the pulses during the swoosh show a chromatic dependence of the maximum offset from the normal emission phase with the offset following a consistent relationship with observing frequency. We also observe that the flux density spectrum of the radio profile during the swoosh is inverted compared to the normal emission. For PSR B1859+07, we have discovered a new mode of emission in the pulsar that is potentially quasi-periodic with a different periodicity than is seen in its swooshes. We invoke an emission model previously proposed in the literature and show that this simple model can explain the macroscopic observed characteristics in both pulsars. We also argue that pulsars that exhibit similar variability on short timescales may have the same underlying emission mechanism.

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Multifrequency behaviour of the anomalous events of PSR J0922+0638

Cited by 6 publications

References 32 publications

FAST ultra-wideband observation of abnormal emission-shift events of PSR B0919+06

FAST ultra-wideband observation of abnormal emission-shift events of PSR B0919+06

On the usefulness of existing solar wind models for pulsar timing corrections

Multi-frequency study of the peculiar pulsars PSR B0919+06 and PSR B1859+07

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