A Second Chromatic Timing Event of Interstellar Origin toward PSR J1713+0747

M. T. Lam, J. A. Ellis, G. Grillo, M. L. Jones, J. S. Hazboun, P. R. Brook, J. E. Turner, S. Chatterjee, J. M. Cordes, T. J. W. Lazio, M. E. DeCesar, Z. Arzoumanian, H. Blumer, H. T. Cromartie, P. B. Demorest, T. Dolch, R. D. Ferdman, E. C. Ferrara, E. Fonseca, N. Garver-DanielsP. A. Gentile, V. Gupta, D. R. Lorimer, R. S. Lynch, D. R. Madison, M. A. McLaughlin, C. Ng, D. J. Nice, T. T. Pennucci, S. M. Ransom, R. Spiewak, I. H. Stairs, D. R. Stinebring, K. Stovall, J. K. Swiggum, S. J. Vigeland, W. W. Zhu

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Abstract

The frequency dependence of radio pulse arrival times provides a probe of structures in the intervening media. Demorest et al. was the first to show a short-term (~100–200 days) reduction in the electron content along the line of sight to PSR J1713+0747 in data from 2008 (approximately MJD 54750) based on an apparent dip in the dispersion measure of the pulsar. We report on a similar event in 2016 (approximately MJD 57510), with average residual pulse-arrival times ≈−3.0, −1.3, and −0.7 μs at 820, 1400, and 2300 MHz, respectively. Timing analyses indicate possible departures from the standard ν −2 dispersive-delay dependence. We discuss and rule out a wide variety of potential interpretations. We find the likeliest scenario to be lensing of the radio emission by some structure in the interstellar medium, which causes multiple frequency-dependent pulse arrival-time delays.
Original languageEnglish
Article number132
JournalAstrophysical Journal
Volume861
DOIs
Publication statusPublished - 12 Jul 2018

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