Constraining the distance to the North Polar Spur with Gaia DR2
- Author(s)
- Kaustav K. Das, Catherine Zucker, Joshua S. Speagle, Alyssa Goodman, Gregory M. Green, João Alves
- Abstract
The North Polar Spur (NPS) is one of the largest structures observed in the Milky Way in both the radio and soft X-rays. While several predictions have been made regarding the origin of the NPS, modelling the structure is difficult without precise distance constraints. In this paper, we determine accurate distances to the southern terminus of the NPS and towards latitudes ranging up to 55°. First, we fit for the distance and extinction to stars towards the NPS using optical and near-infrared photometry and Gaia Data Release 2 astrometry. We model these per-star distance–extinction estimates as being caused by dust screens at unknown distances, which we fit for using a nested sampling algorithm. We then compare the extinction to the Spur derived from our 3D dust modelling with integrated independent measures from XMM–Newton X-ray absorption and H i column density measures. We find that we can account for nearly 100 per cent of the total column density of the NPS as lying within 140 pc for latitudes >26° and within 700 pc for latitudes <11°. Based on the results, we conclude that the NPS is not associated with the Galactic Centre or the Fermi bubbles. Instead, it is likely associated, especially at higher latitudes, with the Scorpius–Centaurus association.
- Organisation(s)
- Department of Astrophysics
- External organisation(s)
- Indian Institute of Technology Kanpur, Harvard-Smithsonian Center for Astrophysics, Harvard University, Max-Planck-Institut für Astronomie
- Journal
- Monthly Notices of the Royal Astronomical Society
- Volume
- 498
- Pages
- 5863-5872
- No. of pages
- 10
- ISSN
- 0035-8711
- DOI
- https://doi.org/10.1093/mnras/staa2702
- Publication date
- 11-2020
- Peer reviewed
- Yes
- Austrian Fields of Science 2012
- 103004 Astrophysics
- Keywords
- ASJC Scopus subject areas
- Astronomy and Astrophysics, Space and Planetary Science
- Portal url
- https://ucrisportal.univie.ac.at/en/publications/630e7518-b682-4c9a-958b-1d3b8292d32c