A-type stars in the Canada-France Imaging Survey II. Tracing the height of the disc at large distances with Blue Stragglers

Guillaume F. Thomas; Chervin F. P. Laporte; Alan W. McConnachie; Benoit Famaey; Rodrigo Ibata; Nicolas F. Martin; Else Starkenburg; Raymond Carlberg; Khyati Malhan; Kim Venn

doi:10.1093/mnras/sty3334

arXiv · 1810.09461

A-type stars in the Canada-France Imaging Survey II. Tracing the height of the disc at large distances with Blue Stragglers

Guillaume F. Thomas·Chervin F. P. Laporte·Alan W. McConnachie·Benoit Famaey·Rodrigo Ibata·Nicolas F. Martin·Else Starkenburg·Raymond Carlberg·Khyati Malhan·Kim Venn

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Abstract

We present the kinematics of Blue Straggler (BS) stars identified in the Canada-France-Imaging-Survey (CFIS), covering 4000 deg$^2$ on the sky in the $u$-band. The BS sample, characterised through CFIS and Pan-STARRS photometry, has been kinematically decomposed into putative halo and disc populations after cross-matching with Gaia astrometry and SDSS/SEGUE/LAMOST spectroscopy. This decomposition clearly reveals the strong flaring of the outer Milky Way disc. In particular, we show that we can detect this flaring up to a vertical height of $|Z| \simeq 8$ kpc at a Galactocentric distance of $R\sim $27 kpc. While some small level of flaring is expected for extended discs built up by radial migration, we demonstrate that this observed very strong flaring of the Milky Way disc is more likely consistent with it being dynamically heated by the repeated passage of the Sagittarius dwarf spheroidal galaxy through the midplane.

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Guillaume F. Thomas, Chervin F. P. Laporte, Alan W. McConnachie, Benoit Famaey, Rodrigo Ibata, Nicolas F. Martin, Else Starkenburg, Raymond Carlberg, Khyati Malhan, Kim Venn. 2018-12-04. A-type stars in the Canada-France Imaging Survey II. Tracing the height of the disc at large distances with Blue Stragglers. https://doi.org/10.1093/mnras%2Fsty3334

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