The DECam eROSITA Survey (DeROSITAS)

The DECam eROSITA Survey (DeROSITAS) is an optical follow-up survey designed to uniformly cover the entire eROSITA-DE footprint, reaching 10σ (5σ) depths of g = 22.7 (23.5), r = 23.2 (24.0), i = 23.3 (24.0), and z = 22.5 (23.2) AB magnitudes.

Under dark conditions at zenith (teff =1), the required exposure times are tg = 25s, tr = 75s, ti = 180s, and tz = 170s. The survey aimed to achieve m+1* depth to enable robust photometric redshift estimation for galaxy clusters (via the red-sequence method) up to z ~ 0.9.

The DeROSITAS survey was conducted between the 2017A and 2022A semesters. Most of the resulting data were published and released as part of the DECaLS DR10 catalog, which includes observations from 8 January 2013 to 30 August 2021 (see the DECaLS viewer). For further details on DeROSITAS, refer to Zenteno et al. (2025).

The sky (and the current coverage as 20210130) in g,r,i, and z are:

Other Surveys:

Pan-STARR depths: grizy < 23.3, 23.2, 23.1, 22.3, 21.3 (3pi stack 5 sigma)

VST-ATLAS depths are similar to SDSS.

We can cover 1000 deg2 in 2.5n (check out this excel ETC).