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The profile of a sample is the multiset of its symbol frequencies. We show that for samples of discrete distributions, profile entropy is a fundamental measure unifying the concepts of estimation, inference, and compression. Specifically,…

Machine Learning · Statistics 2020-02-27 Yi Hao , Alon Orlitsky

A pulsar's pulse profile gets broadened at low frequencies due to dispersion along the line of sight or due to multi-path propagation. The dynamic nature of the interstellar medium makes both of these effects time-dependent and introduces…

The turbulent ionized interstellar medium diffracts radio waves and makes them propagate in multiple paths. The pulse-broadening observed at low frequencies results from the scattering effect of interstellar clouds of ionized gas. During…

High Energy Astrophysical Phenomena · Physics 2025-06-18 W. C. Jing , J. L. Han , C. Wang , P. F. Wang , T. Wang , N. N. Cai , J. Xu , Z. L. Yang , D. J. Zhou , Yi Yan , W. Q. Su , X. Y. Gao , L. Xie

We performed Monte Carlo simulations of different properties of pulsar radio emission, such as: pulsar periods, pulse-widths, inclination angles and rates of occurrence of interpulse emission (IP). We used recently available large data sets…

Astrophysics of Galaxies · Physics 2011-06-29 Krzysztof Maciesiak , Janusz Gil , Valério A. R. M. Ribeiro

This paper describes a comprehensive measurement model for the error budget of pulse arrival times with emphasis on intrinsic pulse jitterand plasma propagation effects (particularly interstellar scattering), which are stochastic in time…

Instrumentation and Methods for Astrophysics · Physics 2010-10-20 J. M. Cordes , R. M. Shannon

Astronomical radio bursts disperse while traveling through the interstellar medium. To optimally detect a short-duration signal within a frequency band, we have to precisely compensate for the pulse dispersion, which is a computationally…

Instrumentation and Methods for Astrophysics · Physics 2018-03-28 Barak Zackay , Eran O. Ofek

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…

In this paper, we describe a novel experiment for the accurate estimation of pulsar dispersion measures using the Giant Metre-wave Radio Telescope. This experiment was carried out for a sample of twelve pulsars, over a period of more than…

Astrophysics · Physics 2009-11-10 A. L. Ahuja , Y. Gupta , D. Mitra , A. K. Kembhavi

An interpulse search was carried out in a sample of 96 pulsars observed on the Large Phased Array (LPA) radio telescope in the Pushchino Multibeams Pulsar Search (PUMPS). The pulsar sample is complete for pulsars having a signal-to-noise…

High Energy Astrophysical Phenomena · Physics 2025-03-25 M. O. Toropov , S. A. Tyul'bashev , V. S. Beskin

In our previous paper, we developed a technique for identifying pulsar candidates in interferometric radio images using their distinctive scintillation signatures. Building on this technique, the present study simulates a pulsar population…

Instrumentation and Methods for Astrophysics · Physics 2026-01-06 Jitendra Salal , Shriharsh P. Tendulkar , Visweshwar Ram Marthi

We investigate the use of bright single pulses from the Crab pulsar to determine separately the dispersion measure (DM) for the Main Pulse and Interpulse components. We develop two approaches using cross correlation functions (CCFs). The…

Solar and Stellar Astrophysics · Physics 2022-08-31 N. Lewandowska , P. B. Demorest , M. A. McLaughlin , P. Kilian , T. H. Hankins

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,…

Precision pulsar timing requires optimization against measurement errors and astrophysical variance from the neutron stars themselves and the interstellar medium. We investigate optimization of arrival time precision as a function of radio…

High Energy Astrophysical Phenomena · Physics 2018-06-28 M. T. Lam , M. A. McLaughlin , J. M. Cordes , S. Chatterjee , T. J. W. Lazio

Shannon Entropy is the preeminent tool for measuring the level of uncertainty (and conversely, information content) in a random variable. In the field of communications, entropy can be used to express the information content of given…

Information Theory · Computer Science 2024-11-06 Bill Kay , Audun Myers , Thad Boydston , Emily Ellwein , Cameron Mackenzie , Iliana Alvarez , Erik Lentz

In an earlier paper (Ahuja, et al, 2005), based on simultaneous multi-frequency observations with the Giant Metrewave Radio Telescope (GMRT), we reported the variation of pulsar dispersion measures (DMs) with frequency. A few different…

Astrophysics · Physics 2008-11-26 Amrit Lal Ahuja , Dipanjan Mitra , Yashwant Gupta

Measurements of pulsar flux densities are of great importance for understanding the pulsar emission mechanism and for predictions of pulsar survey yields and the pulsar population at large. Typically these flux densities are determined from…

Astrophysics of Galaxies · Physics 2015-08-26 M. Kuniyoshi , J. P. W. Verbiest , K. J. Lee , B. Adebahr , M. Kramer , A. Noutsos

We report the detection of 48 millisecond pulsars (MSPs) out of 75 observed thus far using the LOFAR in the frequency range 110-188 MHz. We have also detected three MSPs out of nine observed in the frequency range 38-77 MHz. This is the…

A search for pulse signals was carried out in a new sky area included in the monitoring program for the search for pulsars and transients. Processing of several months data recorded in six frequency channels with a total bandwidth of 2.5…

High Energy Astrophysical Phenomena · Physics 2022-07-20 V. A. Samodurov , S. A. Tyul'bashev , M. O. Toropov , S. V. Logvinenko

Pulsar radio emission undergoes dispersion due to the presence of free electrons in the interstellar medium (ISM). The dispersive delay in the arrival time of pulsar signal changes over time due to the varying ISM electron column density…

Low-frequency pulsar observations are crucial for understanding pulsar emission spectra and population physics, as well as for probing the interstellar medium (ISM) and Earth's ionosphere. We report the largest low-frequency pulsar census…

High Energy Astrophysical Phenomena · Physics 2026-04-01 Pratik Kumar , Marcin Sokolowski , Randall Wayth
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