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Related papers: On Frequency-Dependent Dispersion Measures and Ext…

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Pulsar timing at low frequencies offers a powerful tool for studying the interstellar medium. Additionally, pulsar observations in the ecliptic enables us to study the effects of the solar wind which becomes much more prominent at low radio…

High Energy Astrophysical Phenomena · Physics 2025-06-25 S. C. Susarla , O. A. Johnson , D. J. McKenna , E. F. Keane , P. J. McCauley , J. P. W. Verbiest , C. Tiburzi , A. Golden

Radio pulsars emit regular bursts of radio radiation that propagate through the interstellar medium (ISM), the tenuous gas and plasma between the stars. Previously known dispersive properties of the ISM cause low frequency pulses to be…

Astrophysics of Galaxies · Physics 2014-11-20 F. A. Jenet , D. Fleckenstein , A. Ford , A. Garcia , R. Miller , J. Rivera , K. Stovall

Density fluctuations in the ionised interstellar medium have a profound effect on radio pulsar observations, through angular scattering, intensity scintillations, and small changes in time delays from dispersion. Here we show that it is…

High Energy Astrophysical Phenomena · Physics 2023-04-12 Daniel J. Reardon , William A. Coles

Making precise measurements of pulsar dispersion measures (DMs) and applying suitable corrections for them is amongst the major challenges in high-precision timing programmes such as pulsar timing arrays (PTAs). While the advent of…

High Energy Astrophysical Phenomena · Physics 2022-05-25 Dilpreet Kaur , N. D. Ramesh Bhat , Shi Dai , Samuel J. McSweeney , Ryan M. Shannon , Sanjay Kudale , Willem van Straten

We give a new numerical model of pulsar pulse radiation through the interstellar medium (ISM) considering the propagation effects. It explains the deficit of a scattering measure at the decameter range of frequencies that leads to the…

Astrophysics of Galaxies · Physics 2015-06-11 O. M. Ulyanov , A. A. Seredkina , A. I. Shevtsova

In extreme scattering events, the brightness of a compact radio source drops significantly, as light is refracted out of the line of sight by foreground plasma lenses. Despite recent efforts, the nature of these lenses has remained a…

High Energy Astrophysical Phenomena · Physics 2023-06-28 Hengrui Zhu , Daniel Baker , Ue-Li Pen , Dan R. Stinebring , Marten H. van Kerkwijk

The scattering of fast radio bursts (FRBs) by the intergalactic medium (IGM) is explored using cosmological hydrodynamical simulations. We confirm that the scattering by the clumpy IGM has significant line-of-sight variations. We…

Cosmology and Nongalactic Astrophysics · Physics 2018-10-17 Weishan Zhu , Long-Long Feng , Fupeng Zhang

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 multi-frequency scatter broadening evolution of 29 pulsars observed with the LOw Frequency ARray (LOFAR) and Long Wavelength Array (LWA). We conducted new observations using LOFAR Low Band Antennae (LBA) as well as utilized the…

High Energy Astrophysical Phenomena · Physics 2019-06-26 M. A. Krishnakumar , Yogesh Maan , Bhal Chandra Joshi , P. K. Manoharan

Dispersion in the interstellar medium is a well known phenomenon that follows a simple relationship, which has been used to predict the time delay of dispersed radio pulses since the late 1960s. We performed wide-band simultaneous…

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

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

The frequency dependence of radio pulse arrival times provides a probe of structures in the intervening media. Demorest et al. 2013 was the first to show a short-term (~100-200 days) reduction in the electron content along the line of sight…

We have observed a complex and continuous change in the integrated pulse profile of PSR B2217+47, manifested as additional components trailing the main peak. These transient components are detected over 6 years at $150$ MHz using the LOw…

The dispersion measure (DM) is one of the key attributes of radio pulsars and Fast Radio Bursts (FRBs). There is a mistaken view that the DM is an accurate measure of the column density of electrons between the observer and the source. To…

High Energy Astrophysical Phenomena · Physics 2020-07-07 S. R. Kulkarni

We report the detection of an extreme flux decrease accompanied by clear dispersion measure (DM) and rotation measure (RM) variations for pulsar B1929+10 during the 110-minute radio observation with the Five-hundred-meter Aperture Spherical…

High Energy Astrophysical Phenomena · Physics 2024-10-23 Zhengli Wang , Shunshun Cao , Jiguang Lu , Yulan Liu , Xun Shi , Jinchen Jiang , Enwei Liang , Weiyang Wang , Heng Xu , Renxin Xu

Signals from radio pulsars show a wavelength-dependent delay due to dispersion in the interstellar plasma. At a typical observing wavelength, this delay can vary by tens of microseconds on five-year time scales, far in excess of signals of…

Extreme scattering events (ESEs) are distinctive fluctuations in the brightness of astronomical radio sources caused by occulting plasma lenses in the interstellar medium. The inferred plasma pressures of the lenses are $\sim 10^3$ times…

Radio pulses from pulsars are affected by plasma dispersion, which results in a frequency-dependent propagation delay. Variations in the magnitude of this effect lead to an additional source of red noise in pulsar timing experiments,…