2015/01/19 by O. Wucknitz, Wucknitz, Olaf · 2 citations
Physics and Astronomy · #Astrophysical Phenomena and Observations #Astrophysics of Galaxies (astro-ph.GA) #FOS: Physical sciences #High Energy Astrophysical Phenomena (astro-ph.HE) #Pulsars and Gravitational Waves Research #Radio Astronomy Observations and Technology
paper · pdf · doi:10.48550/arxiv.1501.04510
openalex publication_date 2015/01/19 · openalex created_date 2022/10/03 · openalex updated_date 2026/07/28
Temporal scatter-broadening can seriously affect our ability to find pulsars\norbiting the central mass in our Galaxy. Many of these invaluable probes of\ngeometry around the black hole are expected, but none have been found in close\norbits so far, possibly as result of strong scattering. The magnetar PSR\nJ1745-2900 discovered in 2013 at a separation of < 3 arcsec is not the optimal\ntype of pulsar for studies of general relativity, but it can be used to\ninvestigate the scattering properties so that search strategies can be adapted\naccordingly. This contribution presents an observation of this magnetar using\nshort baselines between VLBI stations in Europe in a non-standard\ninterferometry mode. The most important goal is determining the distance of the\nscattering screen, or the distribution of scattering material if not confined\nto one screen. The analysis is based on phase-binned visibilities that allow\nmeasuring the shape of the scattering disk and how it grows with increasing\ndelay over the scattering tail of the pulse profile. Narrow rings growing with\nthe square root of delay are expected for a single thin scattering screen and\nthe preliminary results are indeed consistent with this expectation. This means\nthat most of the angular and temporal broadening is caused by the same and\nrelatively thin scattering screen and that, in contrast to standard models of\nthe interstellar scattering behaviour near the Galactic centre, this screen is\nlocated about halfway between the centre and us.\n