H{alpha} stars in M31 HST photometry : J/MNRAS/465/4180


Authors : Prichard L.J. orcid , Guhathakurta P., Hamren K.M. (hide) , Guhathakurta P., Hamren K.M. et..al

Bibcode : 2017MNRAS.465.4180P (ADS) (Simbad) (Objects) (hide)

CDS Keywords : Galaxies, nearby; Stars, emission; Photometry, HST; Radial velocities
UAT : Galaxies, Emission line stars, HST photometry, Radial velocity

Observation (OC)

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Inserted into VizieR : 12-Sep-2019
Last modification : 16-Aug-2024

Emission-line stars in M31 from the SPLASH and PHAT surveys. (2017)

Keywords : surveys - stars AGB and post-AGB - stars: emission-line - Be, stars: variables: general - Local Group - galaxies: stellar content

Abstract:We present a sample of 224 stars that emit H{alpha} (H{alpha} stars) in the Andromeda galaxy (M31). The stars were selected from ~5000 spectra, collected as part of the Spectroscopic and Photometric Landscape of Andromeda's Stellar Halo survey using Keck II/DEIMOS. We used six-filter Hubble Space Telescope photometry from the Panchromatic Hubble Andromeda Treasury survey to classify and investigate the properties of the H{alpha} stars. We identified five distinct categories of H{alpha} star: B-type main-sequence (MS) stars, 'transitioning'-MS (T-MS) stars, red core He burning (RHeB) stars, non-C-rich asymptotic giant branch (AGB) stars, and C-rich AGB stars. We found that ~12 per cent of B-type stars exhibit H{alpha} emission ...(more)
Abstract: (hide)
The PHAT survey is a multicycle HST programme. The survey covers around a third of M31's disc in six filters that span from ultraviolet (UV) to near-infrared (NIR). With HST's observing capabilities, the disc of M31, out to 20kpc, is resolved into more than 100 million stars. Dalcanton et al. (2012ApJS..200...18D) chose to observe the northeast quadrant of M31 as it has the least obscured active star-forming regions and least extinction. The spatial coverage selected by the PHAT team also maximized the range of environments and thus stellar evolutionary stages observed. They used two UV filters (F275W and F336W), one optical filter (F475W), one far-red filter (F814W), and two NIR filters (F110W and F160W). The filters were chosen to constrain extinction and effective temperature of a range of stellar populations. To select H{alpha} stars, we used a spectroscopic sample that was collected as part of the SPLASH survey.


                
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