Local group dwarf galaxy detection limit in the CSST survey

Han Qu , Zhen Yuan (1) , Amandine Doliva-Dolinsky (1) , Nicolas F. Martin (1) , Xi Kang , Chengliang Wei , Guoliang Li , Yu Luo , Jiang Chang , Chaowei Tsai , Zhou Fan , Rodrigo Ibata (1)

1 ObAS - Observatoire astronomique de Strasbourg

We predict the dwarf galaxy detection limits for the upcoming Chinese Space Station Telescope (CSST) survey that will cover 17,500 deg² of the sky with a wide field of view of 1.1 deg². The point-source depth reaches 26.3 mag in the g band and 25.9 mag in the i band. Constructing mock survey data based on the designed photometric bands, we estimate the recovery rate of artificial dwarf galaxies from mock point-source photometric catalogues. The detection of these artificial dwarf galaxies is strongly dependent on their distance, magnitude and size, in agreement with searches in current surveys. We expect CSST to enable the detection of dwarf galaxies with M_V = -3.0 and μ₂₅₀ = 32.0 mag/arcsec² (surface-brightness limit for a system of half-light radius r_h = 250 pc) at 400 kpc, and M_V = -4.9 and μ₂₅₀ = 30.5 mag/arcsec² around the Andromeda galaxy. Beyond the Local Group, the CSST survey will achieve M_V = -5.8, and μ₂₅₀ = 29.7 mag/arcsec² in the distance range of 1-2 Mpc, opening up an exciting discovery space for faint field dwarf galaxies. With its optical bands, wide survey footprint, and space resolution, CSST will undoubtedly expand our knowledge of low-mass dwarf galaxies to an unprecedented volume.

Mots clés: galaxies: Local Group; galaxies: dwarf; Astrophysics - Astrophysics of Galaxies

Domaines: Planète et Univers [physics]

Han Qu, Zhen Yuan, Amandine Doliva-Dolinsky, Nicolas F. Martin, Xi Kang, et al.. Local group dwarf galaxy detection limit in the CSST survey. Monthly Notices of the Royal Astronomical Society, 2023, ⟨10.1093/mnras/stad1352⟩. ⟨insu-04097854⟩