A Dense Plasma Globule in the Solar Neighborhood
Abstract
The radio source J1819+3845 underwent a period of extreme interstellar scintillation between circa 1999 and 2007. The plasma structure responsible for this scintillation was determined to be just 1–3 pc from the solar system and to posses a density of n_e ~ 10^2 cm^(−3), which is three orders of magnitude higher than the ambient interstellar density. Here we present radio-polarimetric images of the field toward J1819+3845 at wavelengths of 0.2, 0.92, and 2 m. We detect an elliptical plasma globule of approximate size 1° x ≳2° (major-axis position angle of ≈-40°), via its Faraday-rotation imprint (≈15 rad m^(-2)) on the diffuse Galactic synchrotron emission. The extreme scintillation of J1819+3845 was most likely caused at the turbulent boundary of the globule (J1819+3845 is currently occulted by the globule). The origin and precise nature of the globule remain unknown. Our observations represent the first time that plasma structures which likely cause extreme scintillation have been directly imaged.
Additional Information
© 2017 The American Astronomical Society. Received 2017 July 13; revised 2017 September 16; accepted 2017 September 20; published 2017 October 20. The Westerbork Synthesis Radio Telescope is operated by the ASTRON (Netherlands Institute for Radio Astronomy) with support from the Netherlands Foundation for Scientific Research (NWO). This paper is based (in part) on data obtained with the International LOFAR Telescope (ILT). LOFAR (van Haarlem et al. 2013) is the Low Frequency Array designed and constructed by ASTRON. It has facilities in several countries, that are owned by various parties (each with their own funding sources), and that are collectively operated by the ILT foundation under a joint scientific policy. Virginia Tech Spectral-Line Survey (VTSS) is supported by the National Science Foundation.Attached Files
Published - Vedantham_2017_ApJL_849_L3.pdf
Accepted Version - 1710.07652.pdf
Files
Name | Size | Download all |
---|---|---|
md5:cb893d2e2e2217f084646ec0356bec71
|
3.0 MB | Preview Download |
md5:950dd9b59149bf5a818a4130f9095d55
|
4.0 MB | Preview Download |
Additional details
- Eprint ID
- 82576
- Resolver ID
- CaltechAUTHORS:20171023-103617359
- Nederlandse Organisatie voor Wetenschappelijk Onderzoek (NWO)
- NSF
- Created
-
2017-10-24Created from EPrint's datestamp field
- Updated
-
2021-11-15Created from EPrint's last_modified field