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Electrons densities in different locations of our galaxy are obtained in pulsar astronomy by dividing the dispersion measure (DM) by the distance of the pulsar to Earth. The properties of the interstellar plasma are related to its heating.…

High Energy Astrophysical Phenomena · Physics 2023-12-05 Y. Ben-Aryeh

It was recently suggested by Boldyrev & Gwinn that the characteristics of radio scintillations from distant pulsars are best understood if the interstellar electron-density fluctuations that cause the time broadening of the radio pulses…

Astrophysics · Physics 2010-11-11 Stanislav Boldyrev , Arieh Konigl

High-precision pulsar timing requires accurate corrections for dispersive delays of radio waves, parametrized by the dispersion measure (DM), particularly if these delays are variable in time. In a previous paper we studied the Solar-wind…

We present the results from nearly three years of monitoring of the variations in dispersion measure (DM) along the line-of-sight to 11 millisecond pulsars using the Giant Metrewave Radio Telescope (GMRT). These results demonstrate…

High Energy Astrophysical Phenomena · Physics 2015-06-11 Ujjwal Kumar , Yashwant Gupta , Willem van Straten , Stefan Oslowski , Jayanta Roy , N. D. R. Bhat , Matthew Bailes , Michael J. Keith

Fast radio bursts (FRBs) are very energetic pulses of unknown physical origin. These can be used to study the intergalactic medium (IGM) thanks to their dispersion measure (DM). The DM has several contributions that can be measured (or…

The repeating fast radio burst (FRB) 121102 was recently localized in a dwarf galaxy at a cosmological distance. The dispersion measure (DM) derived for each burst from FRB 121102 so far has not shown significant evolution, even though an…

High Energy Astrophysical Phenomena · Physics 2017-09-27 Yuan-Pei Yang , Bing Zhang

The North American Nanohertz Observatory for Gravitational Waves (NANOGrav) project has the primary goal of detecting and characterizing low-frequency gravitational waves through high-precision pulsar timing. The mitigation of interstellar…

High Energy Astrophysical Phenomena · Physics 2021-07-07 Megan L. Jones , Maura A. McLaughlin , Jayanta Roy , Michael T. Lam , James M. Cordes , David L. Kaplan , Bhaswati Bhattacharyya , Lina Levin

Fast radio bursts (FRBs) are short-duration radio transients of unknown origin. Thus far, they have been blindly detected at millisecond timescales with dispersion measures (DMs) between 110--2600\,pc\,cm$^{-3}$. However, the observed pulse…

High Energy Astrophysical Phenomena · Physics 2019-07-10 Liam Connor

We present simulations of scattering phenomena which are important in pulsar observations, but which are analytically intractable. The simulation code, which has also been used for solar wind and atmospheric scattering problems, is…

Astrophysics of Galaxies · Physics 2015-05-19 W. A. Coles , B. J. Rickett , J. J. Gao , G. Hobbs , J. P. W. Verbiest

In this paper we introduce a new Python package, the Pulsar Signal Simulator, or PsrSigSim, which is designed to simulate a pulsar signal from emission at the pulsar, through the interstellar medium, to observation by a radio telescope, and…

High Energy Astrophysical Phenomena · Physics 2021-03-31 Brent J. Shapiro-Albert , Jeffrey S. Hazboun , Maura A. McLaughlin , Michael T. Lam

Here we present a Bayesian method of including discrete measurements of dispersion measure due to the interstellar medium in the direction of a pulsar as prior information in the analysis of that pulsar. We use a simple simulation to show…

Instrumentation and Methods for Astrophysics · Physics 2013-12-10 Lindley Lentati , Paul Alexander , Michael P. Hobson

We present a detailed study of the complex time-frequency structure of a sample of previously reported bursts of FRB 121102 detected with the MeerKAT telescope in September 2019. The wide contiguous bandwidth of these observations have…

The pulse widths, dispersion measures and dispersion indices of Fast Radio Bursts (FRB) impose coupled constraints that all models must satisfy. We show that if the dispersion measures resulted from propagation through the intergalactic…

High Energy Astrophysical Phenomena · Physics 2015-01-07 J. I. Katz

We have made observations of 98 low-Galactic-latitude pulsars to measure pulse broadening caused by multipath propagation through the interstellar medium. Data were collected with the 305-m Arecibo telescope at four radio frequencies…

The dispersion measure (DM) of fast radio bursts (FRBs) provides a unique way to probe ionised baryons in the intergalactic medium (IGM). Cosmological models with different parameters lead to different DM-redshift ($\mathrm{DM}-z$)…

Cosmology and Nongalactic Astrophysics · Physics 2021-07-07 Adam J. Batten , Alan R. Duffy , Nastasha Wijers , Vivek Gupta , Chris Flynn , Joop Schaye , Emma Ryan-Weber

Light travel time changes due to gravitational waves may be detected within the next decade through precision timing of millisecond pulsars. Removal of frequency-dependent interstellar medium (ISM) delays due to dispersion and scattering is…

Instrumentation and Methods for Astrophysics · Physics 2015-12-16 Nipuni Palliyaguru , Daniel Stinebring , Maura McLaughlin , Paul Demorest , Glenn Jones

Fast radio bursts (FRBs) are millisecond-duration radio transients. As they propagate through the interstellar medium, they interact with free electrons, resulting in dispersion. The corresponding dispersion measure (DM) is referred to as…

High Energy Astrophysical Phenomena · Physics 2026-04-03 Yi Feng , Dengke Zhou , Y. -K. Zhang , D. Li , Jianhua Fang , Jiaying Xu , Chenyuan Xu , Jintao Xie

Extragalactic Fast Radio Bursts (FRBs) have large dispersion measures (DMs) and are unique probes of intergalactic electron density fluctuations. By using the recently released First CHIME/FRB Catalog, we reexamined the structure function…

Cosmology and Nongalactic Astrophysics · Physics 2021-12-08 Siyao Xu , David H. Weinberg , Bing Zhang

Radio waves propagating from distant pulsars in the interstellar medium (ISM), are refracted by electron density inhomogeneities, so that the intensity of observed pulses fluctuates with time. The theory relating the observed pulse…

Astrophysics · Physics 2009-11-10 Stanislav Boldyrev , Carl R. Gwinn

Radio pulsars allow the study of the ionised interstellar medium and its dispersive effects, a major noise source in gravitational wave searches using pulsars. In this paper, we compare the functionality and reliability of three commonly…