Multifrequency Observations of Radio Pulse Broadening and Constraints on Interstellar Electron Density Microstructure

Bhat, N. D. R.; Cordes, J. M.; Camilo, F.; Nice, D. J.; Lorimer, D. R.

doi:10.1086/382680

Cited by 351 publications

(504 citation statements)

References 39 publications

(58 reference statements)

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“…This yielded τs values of 0.07 and 0.26 ms for S-band and L-band, respectively. Our results are within the uncertainties of models estimating τs based on measured pulsar DM (Cordes & Lazio 2003, Bhat et al 2004. We estimate the flux density of PSR J1751−2737 based on the radiometer equation, the average pulse profile of each detection, the parameters in Table 2, and the background sky temperature T sky at each frequency.…”

Section: Gbtsupporting

confidence: 68%

Searching for pulsars associated with the Fermi GeV excess

Bhakta

Deneva

Frail

et al. 2017

Monthly Notices of the Royal Astronomical Society

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The Fermi Large Area Telescope has detected an extended region of GeV emission toward the Galactic Center that is currently thought to be powered by dark matter annihilation or a population of young and/or millisecond pulsars. In a test of the pulsar hypothesis, we have carried out an initial search of a 20 deg 2 area centered on the peak of the galactic center GeV excess. Candidate pulsars were identified as a compact, steep spectrum continuum radio source on interferometric images and followed with targeted single-dish pulsation searches. We report the discovery of the recycled pulsar PSR 1751−2737 with a spin period of 2.23 ms. PSR 1751−2737 appears to be an isolated recycled pulsar located within the disk of our Galaxy, and it is not part of the putative bulge population of pulsars that are thought to be responsible for the excess GeV emission. However, our initial success in this small pilot survey suggests that this hybrid method (i.e. wide-field interferometric imaging followed up with single dish pulsation searches) may be an efficient alternative strategy for testing whether a putative bulge population of pulsars is responsible for the GeV excess.

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Section: Gbtsupporting

confidence: 68%

Searching for pulsars associated with the Fermi GeV excess

Bhakta

Deneva

Frail

et al. 2017

Monthly Notices of the Royal Astronomical Society

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“…Along a given line of sight it also shows a dependence on the total electron content, i.e. DM, but there are deviations from this relation of at least an order of magnitude (Bhat et al 2004). Considering the same pulsar and observing frequecy and system as discussed in the first paragraph of this section, and using the relation between dispersion measure and scattering from Bhat et al (2004) we find that the scattering delay would lie between 0.01 and 1 s. The stochastic nature of scattering means that it is difficult to uniquely correct for it without an underlying assumption for the intrinsic pulse shape; thus, scattering becomes the limiting factor on the distance out to which low-frequency observations can be used for detailed study, or even detection, of pulsars of given rotational periods.…”

Section: Interstellar Mediummentioning

confidence: 98%

Observing pulsars and fast transients with LOFAR

Stappers

Hessels

Alexov

et al. 2011

A&A

213

160

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Low frequency radio waves, while challenging to observe, are a rich source of information about pulsars. The LOw Frequency ARray (LOFAR) is a new radio interferometer operating in the lowest 4 octaves of the ionospheric "radio window": 10-240 MHz, that will greatly facilitate observing pulsars at low radio frequencies. Through the huge collecting area, long baselines, and flexible digital hardware, it is expected that LOFAR will revolutionize radio astronomy at the lowest frequencies visible from Earth. LOFAR is a next-generation radio telescope and a pathfinder to the Square Kilometre Array (SKA), in that it incorporates advanced multi-beaming techniques between thousands of individual elements. We discuss the motivation for low-frequency pulsar observations in general and the potential of LOFAR in addressing these science goals. We present LOFAR as it is designed to perform high-time-resolution observations of pulsars and other fast transients, and outline the various relevant observing modes and data reduction pipelines that are already or will soon be implemented to facilitate these observations. A number of results obtained from commissioning observations are presented to demonstrate the exciting potential of the telescope. This paper outlines the case for low frequency pulsar observations and is also intended to serve as a reference for upcoming pulsar/fast transient science papers with LOFAR.

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“…Lorimer & Kramer 2004) and pulse broadening caused by interstellar scattering scales as τs ∝ f −3.86±0.16 (Bhat et al 2004). Therefore, pulsar timing data from high-frequency observations will contain less significant red ISM noise.…”

Section: Pta Monitoring Of Msps At High Frequenciesmentioning

confidence: 99%

Prospects for high-precision pulsar timing with the new Effelsberg PSRIX backend

Lazarus¹,

Karuppusamy²,

Graikou³

et al. 2016

Mon. Not. R. Astron. Soc.

137

112

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The PSRIX backend is the primary pulsar timing instrument of the Effelsberg 100-m radio telescope since early 2011. This new ROACH-based system enables bandwidths up to 500 MHz to be recorded, significantly more than what was possible with its predecessor, the Effelsberg-Berkeley Pulsar Processor (EBPP). We review the first four years of PSRIX timing data for 33 pulsars collected as part of the monthly European Pulsar Timing Array (EPTA) observations. We describe the automated data analysis pipeline, CoastGuard, that we developed to reduce these observations. We also introduce TOASTER, the EPTA timing database used to store timing results, processing information and observation metadata. Using these new tools, we measure the phase-averaged flux densities at 1.4 GHz of all 33 pulsars. For 7 of these pulsars, our flux density measurements are the first values ever reported. For the other 26 pulsars, we compare our flux density measurements with previously published values. By comparing PSRIX data with EBPP data, we find an improvement of ∼2-5 times in signal-to-noise ratio achievable, which translates to an increase of ∼2-5 times in pulse time-of-arrival (TOA) precision. We show that such an improvement in TOA precision will improve the sensitivity to the stochastic gravitational wave background. Finally, we showcase the flexibility of the new PSRIX backend by observing several millisecond-period pulsars (MSPs) at 5 and 9 GHz. Motivated by our detections, we discuss the potential for complementing existing pulsar timing array data sets with MSP monitoring campaigns at these frequencies.

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Multifrequency Observations of Radio Pulse Broadening and Constraints on Interstellar Electron Density Microstructure

Cited by 351 publications

References 39 publications

Searching for pulsars associated with the Fermi GeV excess

Searching for pulsars associated with the Fermi GeV excess

Observing pulsars and fast transients with LOFAR

Prospects for high-precision pulsar timing with the new Effelsberg PSRIX backend

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