DOE OSTI · 3377519
DESI Data Release 2 ELGs: Property-dependent subsamples, imaging systematics, and clustering
Abstract
Using emission-line galaxies (ELGs) from the Dark Energy Spectroscopic Instrument (DESI) Data Release 2, we evaluate a property-dependent correction to imaging systematics. We derive systematic weights following the same linear regression method used for other DESI tracers, but do so separately on ELG subsamples to provide a physically-informed alternative to the fiducial, neural-network-based approach. In doing so, we show that the deeper imaging in the Dark Energy Survey (DES) footprint leads to a higher overall number density but a lack of targets with extreme $g-r$ and $r-z$ colors. ELGs in the DES region also show a distinct redshift distribution when subsampled by position in the $g-r$ vs. $r-z$ plane. To address these effects, we implement a separate treatment of the DES footprint within the DESI catalog production pipeline, which is generally well-motivated and, in some cases, imperative for accurate clustering measurements. With DES treated separately, we find that property-dependent systematic weights further mitigate spurious clustering signal in $\sim$10% of subsamples, while the fiducial scheme remains optimal for the full sample.
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Hagen, T. [Utah U.], Dawson, K. S. [Utah U.], Zheng, Z. [Utah U.], Aguilar, J. [LBNL, Berkeley], Ahlen, S. [Boston U.], Bianchi, D. [Milan U.; Brera Observ.], Brooks, D. [University Coll. London], Claybaugh, T. [LBNL, Berkeley], de la Macorra, A. [UNAM, Mexico], Dey, B. [Toronto U., Astron. Dept.; Pittsburgh U.], Ferraro, S. [LBNL, Berkeley; UC, Berkeley, Math. Dept.], Forero-Romero, J. E. [Andes U., Bogota], Gontcho A. Gontcho, S. [Virginia U.], Gutierrez, G. [Fermilab], Guy, J. [LBNL, Berkeley], Hahn, C. [Texas U.; Texas U., TCC], Ishak, M. [U. Texas, Dallas], Joyce, R. [Natl. Solar Observ., Tucson], Juneau, S. [Natl. Solar Observ., Tucson], Kremin, A. [LBNL, Berkeley], Lahav, O. [University Coll. London], Lamman, C. [Ohio State U.], Landriau, M. [LBNL, Berkeley], Le Guillou, L. [LPNHE, Paris], Manera, M. [Barcelona, IFAE; Barcelona, Autonoma U.], Meisner, A. [Natl. Solar Observ., Tucson], Miquel, R. [ICREA, Barcelona; Barcelona, IFAE], Moustakas, J. [Siena Coll., Loudonville], Myers, A. D. [Wyoming U.], Nadathur, S. [Portsmouth U., ICG], Newman, J. A. [Pittsburgh U.], Niz, G. [Guanajuato U.; Mexico U., ICN], Percival, W. J. [Waterloo U.; Perimeter Inst. Theor. Phys.], Poppett, C. [LBNL, Berkeley; UC, Berkeley (main); UC, Berkeley, Math. Dept.], Prada, F. [Granada U., Theor. Phys. Astrophys.], Pérez-Ràfols, I. [Barcelona, Polytechnic U.], Ross, A. J. [Chicago U., KICP; Ohio State U., Dept. Astron.; Ohio State U.], Rossi, G. [Sejong U.], Saito, S. [Missouri U., Rolla], Sanchez, E. [Madrid, CIEMAT], Schlegel, D. [LBNL, Berkeley], Silber, J. [LBNL, Berkeley], Tarlé, G. [Michigan U.; KEK, Tsukuba; Hiroshima Shudo U.], Weaver, B. A. [Natl. Solar Observ., Tucson], Zou, H. [Beijing Observ.]. 2026-06-17. DESI Data Release 2 ELGs: Property-dependent subsamples, imaging systematics, and clustering. https://www.osti.gov/biblio/3377519
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