Giant pulses from the Crab pulsar

Karuppusamy, R.; Stappers, B. W.; Straten, W. van

doi:10.1051/0004-6361/200913729

Cited by 109 publications

(142 citation statements)

References 39 publications

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“…Some of them, however, show variations in amplitude as a function of frequency, which have been seen before (e.g., Karuppusamy et al 2010). We also see variations in amplitude between days, which is likely due to refractive interstellar scintillation (RISS), which can affect the strength of pulses on a timescale of days.…”

Section: Radio Observationssupporting

confidence: 58%

“…In our data, ∼87% of detected GPs were at the phase of the MP, while the other ∼13% were at the phase of the IP. Only 5% of GPs detected by Cordes et al (2004) at 1.2 GHz were at the phase of the IP, but Karuppusamy et al (2010) found that ∼12% of GPs detected at 1.4 GHz were IP GPs. For detected pulses that show up out of phase with the MP and IP, the frequency versus time plots are checked by eye to see if they show the proper quadratic frequency sweep for a DM of 56.8 pc cm −3 .…”

Section: Radio Observationsmentioning

confidence: 89%

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A Giant Sample of Giant Pulses From the Crab Pulsar

Mickaliger

McLaughlin

Lorimer

et al. 2012

ApJ

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We observed the Crab pulsar with the 43 m telescope in Green Bank, WV over a timespan of 15 months. In total we obtained 100 hr of data at 1.2 GHz and seven hours at 330 MHz, resulting in a sample of about 95,000 giant pulses (GPs). This is the largest sample, to date, of GPs from the Crab pulsar taken with the same telescope and backend and analyzed as one data set. We calculated power-law fits to amplitude distributions for main pulse (MP) and interpulse (IP) GPs, resulting in indices in the range of 2.1-3.1 for MP GPs at 1.2 GHz and in the range of 2.5-3.0 and 2.4-3.1 for MP and IP GPs at 330 MHz. We also correlated the GPs at 1.2 GHz with GPs from the Robert C. Byrd Green Bank Telescope (GBT), which were obtained simultaneously at a higher frequency (8.9 GHz) over a span of 26 hr. In total, 7933 GPs from the 43 m telescope at 1.2 GHz and 39,900 GPs from the GBT were recorded during these contemporaneous observations. At 1.2 GHz, 236 (3%) MP GPs and 23 (5%) IP GPs were detected at 8.9 GHz, both with zero chance probability. Another 15 (4%) low-frequency IP GPs were detected within one spin period of high-frequency IP GPs, with a chance probability of 9%. This indicates that the emission processes at high and low radio frequencies are related, despite significant pulse profile shape differences. The 43 m GPs were also correlated with Fermi γ -ray photons to see if increased pair production in the magnetosphere is the mechanism responsible for GP emission. A total of 92,022 GPs and 393 γ -ray photons were used in this correlation analysis. No significant correlations were found between GPs and γ -ray photons. This indicates that increased pair production in the magnetosphere is likely not the dominant cause of GPs. Possible methods of GP production may be increased coherence of synchrotron emission or changes in beaming direction.

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Section: Radio Observationssupporting

confidence: 58%

Section: Radio Observationsmentioning

confidence: 89%

A Giant Sample of Giant Pulses From the Crab Pulsar

Mickaliger

McLaughlin

Lorimer

et al. 2012

ApJ

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“…We can also compare the slopes estimated at other frequencies. Karuppusamy et al (2010) report slopes of −3.0 and −2.8 at 1400 MHz for the main-and interpulses flux distributions, respectively. Similarly, Lundgren et al (1995) find a value of −3.3 at 800 MHz and Cordes et al (2004) report ≈−2.3 at 430 MHz and noted that the slope increased with frequency.…”

Section: Giant Pulse Statisticsmentioning

confidence: 91%

“…3 of Karuppusamy et al (2010). In short, the increase in T sys due to the Crab nebula was multiplied by a factor that is a function of radio frequency and the hour-angle of the Crab pulsar.…”

Section: Flux Calibrationmentioning

confidence: 99%

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Crab giant pulses at low frequencies

Karuppusamy

Stappers

Lee

2012

A&A

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We report observations of the Crab pulsar at frequencies in the range of 110-180 MHz. The combination of coherent dedispersion and the narrow synthesised beam of the Westerbork Synthesis Radio Telescope resulted in a sensitive observation. Our improved sensitivity and resolution allow us to confirm the presence of a precursor to the interpulse at these frequencies. We also detected more than 1000 giant pulses and find that the interpulse precursor component shows no giant pulse emission. Therefore, we attribute it to a similar emission source as the precursor to the mainpulse. Together these precursors might be the normal emission seen from the majority of radio pulsars. From the dispersion-free giant pulses, we find that the emission rate is ∼10-20 × 10 −3 s −1 and the scatter timescale in the range of ∼1.5-5.6 ms. We further find that the radio flux of the pulsar is 6-11 Jy in this frequency range.

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Introduction: Radio Transients

Keane

2011

The Transient Radio Sky

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Giant pulses from the Crab pulsar

Cited by 109 publications

References 39 publications

A Giant Sample of Giant Pulses From the Crab Pulsar

A Giant Sample of Giant Pulses From the Crab Pulsar

Crab giant pulses at low frequencies

Introduction: Radio Transients

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