Beyond 31 mag arcsec‑2: The Frontier of Low Surface Brightness Imaging with the Largest Optical Telescopes

Trujillo, I.; Fliri, J.
Bibliographical reference

The Astrophysical Journal, Volume 823, Issue 2, article id. 123, pp. (2016).

Advertised on:
6
2016
Number of authors
2
IAC number of authors
2
Citations
149
Refereed citations
123
Description
The detection of structures in the sky with optical surface brightnesses fainter than 30 mag arcsec‑2 (3σ in 10 × 10 arcsec boxes; r-band) has remained elusive in current photometric deep surveys. Here we show how present-day telescopes of 10 m class can provide broadband imaging 1.5–2 mag deeper than most previous results within a reasonable amount of time (i.e., <10 hr on-source integration). In particular, we illustrate the ability of the 10.4 m Gran Telescopio de Canarias telescope to produce imaging with a limiting surface brightness of 31.5 mag arcsec‑2 (3σ in 10 × 10 arcsec boxes; r-band) using 8.1 hr on source. We apply this power to explore the stellar halo of the galaxy UGC 00180, a galaxy analogous to M31 located at ∼150 Mpc, by obtaining a radial profile of surface brightness down to μ r ∼ 33 mag arcsec‑2. This depth is similar to that obtained using the star-counts techniques for Local Group galaxies, but is achieved at a distance where this technique is unfeasible. We find that the mass of the stellar halo of this galaxy is ∼4 × 109 M ⊙, i.e., (3 ± 1)% of the total stellar mass of the whole system. This amount of mass in the stellar halo is in agreement with current theoretical expectations for galaxies of this kind.