2008/02/29 by A. Kuzmin, B. Ya. Losovsky, C. A. Jordan +2 · 3 citations
Physics and Astronomy · #Advanced Frequency and Time Standards #Cold Atom Physics and Bose-Einstein Condensates #Pulsars and Gravitational Waves Research #astro-ph
paper · pdf · doi:10.1051/0004-6361:20079211
3 pages, 1 figure, accepted by A&A
arxiv created 2008/02/29 · openalex publication_date 2008/03/04 · arxiv updated 2009/12/01 · openalex created_date 2025/10/10 · openalex updated_date 2026/07/31
In separate series of observations of the Crab pulsar, pulse broadening due to scattering was measured at 111 MHz, and variations of dispersion due to pulse delay were measured at higher radio frequencies. In a remarkable event lasting 200 days a large increase occurred in both parameters and with similar time signatures. The increases in scattering and dispersion measure observed over the 200 days MJD 53 950-54 150 are attributable to the effects of an ionised cloud or filament crossing the line of sight. The cloud would be m across, with electron density cm-3. The increased scattering might originate within the cloud itself, or the moving filament might induce turbulence in a separate higher density cloud in the line of sight.