AbacusSummit

${DESI_ROOT}/survey/catalogs/{RELEASE}/mocks/AbacusSummit hosts 25 Abacus LSS catalogs (and associated random catalogs), separated by {OBSCON} (DARK or BRIGHT) and followed by an internal version. For DARK (LRG, ELG and QSO) the internal version is v4.2 and for BRIGHT (BGS) it is v1.

On this page you will find: the initial catalog in the Y1 footprint (called forFA files), the lrg_mask file (used only to mask LRGs, present only under DARK obscon) and two directories per mock realization called altmtl{MOCKREA} and mock{MOCKREA}, where {MOCKREA} is the mock realization index from 0 to 24.

You will find three distinct mock flavors, depending on the level of realism:

• Complete: no fiber-assigment effects; includes the tracers reachable by any DESI fiber (located under mock{MOCKREA})

• FFA (Fast Fiber Assigment): estimates fiber assigment probabilistically by learning from the data, based on number of passes and local density (also under mock{MOCKREA})

• altmtl: estimated using the same fba algorithm, passes and hardware configuration as in the actual data (found under altmtl{MOCKREA}). To replicate the fiber-assigment processing, see the instructions in LSS repo.

Details about the content and production of the LSS catalogs are given in Ross et al. (2025). These mocks were used in the main BAO cosmological analysis; more information is available in DESI Collaboration (2025).

A comparison of the three mock flavors is described in Bianchi et al. (2025)

• OBSCON : dark or bright