Pulse-to-pulse flux density modulation from pulsars at 8.35 GHz

We report results from simultaneous radio and X-ray observations of PSR B0611+22 which is known to exhibit bursting in its single-pulse emission. The pulse phase of the bursts vary with radio frequency. The bursts are correlated in 327/150 MHz datasets while they are anti-correlated, with bursts at one frequency associated with normal emission at the other, in 820/150 MHz datasets. Also, the flux density of this pulsar is lower than expected at 327 MHz assuming a power law. We attribute this unusual behaviour to the pulsar itself rather than absorption by external astrophysical sources. Using this dataset over an extensive frequency range, we show that the bursting phenomenon in this pulsar exhibits temporal variance over a span of few hours. We also show that the bursting is quasi-periodic over the observed band. The anti-correlation in the phase offset of the burst mode at different frequencies suggests that the mechanisms responsible for phase offset and flux enhancement have different dependencies on the frequency. We did not detect the pulsar with XMM-Newton and place a 99% confidence upper limit on the X-ray efficiency of 10 −5 .

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“…8). Our results are consistent with other pulsars where a similar trend is observed (Maron et al 2013). …”

Section: Broadband Flux Density Modulationsupporting

confidence: 94%

Simultaneous radio and X-ray observations of PSR B0611+22

Rajwade

Seymour²,

Lorimer

et al. 2016

Mon. Not. R. Astron. Soc.

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“…However, lower intensity emission contributes mostly to the leading part of the first component whereas higher intensity single pulses contribute mainly to its trailing part (Fig. 5) which was also reported by Maron et al (2013). The results of analysis of 4.85 GHz and 8.35 GHz data are consistent with previous studies by (Nowakowski 1996) at 430 MHz but studies of B0329+54 (Mitra et al 2007) show entirely opposite behaviour without full explanation.…”

Section: Radio Spectrumsupporting

confidence: 89%

Analysis of single pulse radio flux measurements of PSR B1133+16 at 4.85 and 8.35 GHz

Krzeszowski

Maron

Słowikowska

et al. 2014

Monthly Notices of the Royal Astronomical Society

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We show the results of microsecond resolution radio data analysis focused on flux measurements of single pulses of PSR B1133+16. The data were recorded at 4.85 GHz and 8.35 GHz with 0.5 GHz and 1.1 GHz bandwidth, respectively, using Radio Telescope Effelsberg (MPIfR). The most important conclusion of the analysis is, that the strongest single pulse emission at 4.85 GHz and 8.35 GHz contributes almost exclusively to the trailing part of the leading component of the pulsar mean profile, whereas studies at lower frequencies report that the contribution is spread almost uniformly covering all phases of the pulsar mean profile. We also estimate the radio emission heights to be around 1%-2% of the light cylinder radius which is in agreement with previous studies. Additionally these observations allowed us to add two more measurements of the flux density to the PSR B1133+16 broadband radio spectrum covering frequencies from 16.7 MHz up to 32 GHz. We fit two different models to the spectrum: the broken power law and the spectrum based on flicker noise model, which represents the spectrum in a simpler but similarly accurate way.

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“…On MJD 56836, we observed five normal pulsars with known flux density at 8.35 GHz with same setup as for PSR J1745−2900. Table 1 lists these pulsars and gives their 8.35 GHz flux density measured at Effelsberg (Maron et al 2013), radio spectral index (Malofeev et al 1994), estimated flux density at 8.6 GHz, the flux density in arbitrary units measured with the TMRT, the average elevation angle of the TMRT during the observation, the length of the observation and the scaling factor to convert from TMRT units to mJy. Using the scaling factor of the five normal pulsars, we obtain the weighted average scaling factor and corresponding standard deviation.…”

Section: Observations and Data Reductionmentioning

confidence: 99%

Single-Pulse Radio Observations of the Galactic Center Magnetar PSR J1745–2900

Yan

Shen

et al. 2015

ApJ

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In this paper, we report radio observations of the Galactic Center magnetar PSR J1745−2900 at six epochs between June and October, 2014. These observations were carried out using the new Shanghai Tian Ma Radio Telescope at a frequency of 8.6 GHz. Both the flux density and integrated profile of PSR J1745−2900 show dramatic changes from epoch to epoch showing that the pulsar was in its "erratic" phase. On MJD 56836, the flux density of this magnetar was about 8.7 mJy, which was ten times large than that reported at the time of discovery, enabling a single-pulse analysis. The emission is dominated by narrow "spiky" pulses which follow a log-normal distribution in peak flux density. From 1913 pulses, we detected 53 pulses whose peak flux density is ten times greater than that of the integrated profile. They are concentrated in pulse phase at the peaks of the integrated profile. The pulse widths at the 50% level of these bright pulses was between 0.2 • to 0.9 • , much narrower than that of integrated profile (∼12 • ). The observed pulse widths may be limited by interstellar scattering. No clear correlation was found between the widths and peak flux density of these pulses and no evidence was found for subpulse drifting. Relatively strong spiky pulses are also detected in the other five epochs of

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Pulse-to-pulse flux density modulation from pulsars at 8.35 GHz

Cited by 7 publications

References 30 publications

Simultaneous radio and X-ray observations of PSR B0611+22

Simultaneous radio and X-ray observations of PSR B0611+22

Analysis of single pulse radio flux measurements of PSR B1133+16 at 4.85 and 8.35 GHz

Single-Pulse Radio Observations of the Galactic Center Magnetar PSR J1745–2900

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