A-type stars in the Canada–France Imaging Survey I. The stellar halo of the Milky Way traced to large radius by blue horizontal branch stars. Issue 4 (25th September 2018)
- Record Type:
- Journal Article
- Title:
- A-type stars in the Canada–France Imaging Survey I. The stellar halo of the Milky Way traced to large radius by blue horizontal branch stars. Issue 4 (25th September 2018)
- Main Title:
- A-type stars in the Canada–France Imaging Survey I. The stellar halo of the Milky Way traced to large radius by blue horizontal branch stars
- Authors:
- Thomas, Guillaume F
McConnachie, Alan W
Ibata, Rodrigo A
Côté, Patrick
Martin, Nicolas
Starkenburg, Else
Carlberg, Raymond
Chapman, Scott
Fabbro, Sébastien
Famaey, Benoit
Fantin, Nicholas
Gwyn, Stephen
Hénault-Brunet, Vincent
Malhan, Khyati
Navarro, Julio
Robin, Annie C
Scott, Douglas - Abstract:
- ABSTRACT: We present the stellar density profile of the outer halo of the Galaxy traced over a range of Galactocentric radii in the range 15 < R GC < 220 kpc by blue horizontal branch (BHB) stars. These stars are identified photometrically using deep u -band imaging from the new Canada–France Imaging Survey (CFIS) that reaches 24.5 mag. This is combined with griz bands from Pan-STARRS 1 and covers a total of ∼4000 deg 2 of the northern sky. We present a new method to select BHB stars that has low contamination from blue stragglers and high completeness. We use this sample to measure and parametrize the three-dimensional density profile of the outer stellar halo. We fit the profile using (i) a simple power law with a constant flattening (ii) a flattening that varies as a function of Galactocentric radius (iii) a broken power-law profile. We find that outer stellar halo traced by the BHB is well modelled by a broken power law with a constant flattening of q = 0.86 ± 0.02, with an inner slope of γ = 4.24 ± 0.08. This is much steeper than the preferred outer profile that has a slope of β = 3.21 ± 0.07 after a break radius of $r_\mathrm{ b}=41.4^{+2.5}_{-2.4}$ kpc. The outer profile of the stellar halo trace by BHB stars is shallower than that recently measured using RR Lyrae, a surprising result given the broad similarity of the ages of these stellar populations.
- Is Part Of:
- Monthly notices of the Royal Astronomical Society. Volume 481:Issue 4(2018)
- Journal:
- Monthly notices of the Royal Astronomical Society
- Issue:
- Volume 481:Issue 4(2018)
- Issue Display:
- Volume 481, Issue 4 (2018)
- Year:
- 2018
- Volume:
- 481
- Issue:
- 4
- Issue Sort Value:
- 2018-0481-0004-0000
- Page Start:
- 5223
- Page End:
- 5235
- Publication Date:
- 2018-09-25
- Subjects:
- stars: distances -- stars: horizontal branch -- stars: statistics -- Galaxy: halo -- Galaxy: structure
Astronomy -- Periodicals
Periodicals
520.5 - Journal URLs:
- http://mnras.oxfordjournals.org/ ↗
http://onlinelibrary.wiley.com/journal/10.1111/(ISSN)1365-2966 ↗
http://www.blackwell-synergy.com/issuelist.asp?journal=mnr ↗
http://www.blackwell-synergy.com/loi/mnr ↗
http://ukcatalogue.oup.com/ ↗ - DOI:
- 10.1093/mnras/sty2604 ↗
- Languages:
- English
- ISSNs:
- 0035-8711
- Deposit Type:
- Legaldeposit
- View Content:
- Available online (eLD content is only available in our Reading Rooms) ↗
- Physical Locations:
- British Library DSC - 5943.000000
British Library DSC - BLDSS-3PM
British Library HMNTS - ELD Digital store - Ingest File:
- 12186.xml