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author Siegel, J.
McCullough, J.
Amon, A.
Lamman, C.
Jeffrey, N.
Joachimi, B.
Hoekstra, H.
Heydenreich, S.
Ross, A. J.
Aguilar, J.
Ahlen, S.
Bianchi, D.
Blake, C.
Brooks, D.
Castander, F. J.
Claybaugh, T.
de la Macorra, A.
DeRose, J.
Doel, P.
Emas, N.
Ferraro, S.
Font-Ribera, A.
Forero-Romero, J. E.
Gaztañaga, E.
Gontcho, S. Gontcho A
Gutierrez, G.
Honscheid, K.
Ishak, M.
Joudaki, S.
Kehoe, R.
Kirkby, D.
Kisner, T.
Krolewski, A.
Lahav, O.
Lambert, A.
Landriau, M.
Guillou, L. Le
Levi, M. E.
Manera, M.
Meisner, A.
Miquel, R.
Moustakas, J.
Nadathur, S.
Newman, J. A.
Niz, G.
Palanque-Delabrouille, N.
Percival, W. J.
Porredon, A.
Prada, F.
Pérez-Ràfols, I.
Rossi, G.
Sanchez, E.
Saulder, C.
Schlegel, D.
Schubnell, M.
Semenaite, A.
Silber, J.
Sprayberry, D.
Sun, Z.
Tarlé, G.
Weaver, B. A.
Zhou, R.
Zou, H.
author_facet Siegel, J.
McCullough, J.
Amon, A.
Lamman, C.
Jeffrey, N.
Joachimi, B.
Hoekstra, H.
Heydenreich, S.
Ross, A. J.
Aguilar, J.
Ahlen, S.
Bianchi, D.
Blake, C.
Brooks, D.
Castander, F. J.
Claybaugh, T.
de la Macorra, A.
DeRose, J.
Doel, P.
Emas, N.
Ferraro, S.
Font-Ribera, A.
Forero-Romero, J. E.
Gaztañaga, E.
Gontcho, S. Gontcho A
Gutierrez, G.
Honscheid, K.
Ishak, M.
Joudaki, S.
Kehoe, R.
Kirkby, D.
Kisner, T.
Krolewski, A.
Lahav, O.
Lambert, A.
Landriau, M.
Guillou, L. Le
Levi, M. E.
Manera, M.
Meisner, A.
Miquel, R.
Moustakas, J.
Nadathur, S.
Newman, J. A.
Niz, G.
Palanque-Delabrouille, N.
Percival, W. J.
Porredon, A.
Prada, F.
Pérez-Ràfols, I.
Rossi, G.
Sanchez, E.
Saulder, C.
Schlegel, D.
Schubnell, M.
Semenaite, A.
Silber, J.
Sprayberry, D.
Sun, Z.
Tarlé, G.
Weaver, B. A.
Zhou, R.
Zou, H.
contents We present direct measurements of the intrinsic alignments (IA) of over 2 million spectroscopic galaxies using DESI Data Release 1 and imaging from four lensing surveys: DES, HSC, KiDS, and SDSS. In this uniquely data-rich regime, we take initial steps towards a more tailored IA modelling approach by building a library of IA measurements across colour, luminosity, stellar mass, and redshift. We map the dependence between galaxy type -- in terms of rest-frame colour, strength of the 4000 Angstrom break, and specific star formation rate -- and IA amplitude; the bluest galaxies have an alignment consistent with zero, across low ($0.05<z<0.5$) and high ($0.8<z<1.55$) redshifts. In order to construct cosmic shear samples that are minimally impacted by IA but maintain maximum sample size and statistical power, we map the dependence of alignment with colour purity. Red, quenched galaxies are strongly aligned and the amplitude of the signal increases with luminosity, which is tightly correlated with stellar mass in our catalogues. For DESI galaxies between $0<z<1.5$, trends in luminosity and colour alone are sufficient to explain the alignments we measure -- with no need for an explicit redshift dependence. In a companion paper (Jeffrey et al., in prep), we perform detailed modelling of the IA signals with significant detections, including model comparison. Finally, to direct efforts for future IA measurements, we juxtapose the colour-magnitude-redshift coverage of existing IA measurements against modern and future lensing surveys.
format Preprint
id arxiv_https___arxiv_org_abs_2507_11530
institution arXiv
publishDate 2025
record_format arxiv
spellingShingle Intrinsic alignment demographics for next-generation lensing: Revealing galaxy property trends with DESI Y1 direct measurements
Siegel, J.
McCullough, J.
Amon, A.
Lamman, C.
Jeffrey, N.
Joachimi, B.
Hoekstra, H.
Heydenreich, S.
Ross, A. J.
Aguilar, J.
Ahlen, S.
Bianchi, D.
Blake, C.
Brooks, D.
Castander, F. J.
Claybaugh, T.
de la Macorra, A.
DeRose, J.
Doel, P.
Emas, N.
Ferraro, S.
Font-Ribera, A.
Forero-Romero, J. E.
Gaztañaga, E.
Gontcho, S. Gontcho A
Gutierrez, G.
Honscheid, K.
Ishak, M.
Joudaki, S.
Kehoe, R.
Kirkby, D.
Kisner, T.
Krolewski, A.
Lahav, O.
Lambert, A.
Landriau, M.
Guillou, L. Le
Levi, M. E.
Manera, M.
Meisner, A.
Miquel, R.
Moustakas, J.
Nadathur, S.
Newman, J. A.
Niz, G.
Palanque-Delabrouille, N.
Percival, W. J.
Porredon, A.
Prada, F.
Pérez-Ràfols, I.
Rossi, G.
Sanchez, E.
Saulder, C.
Schlegel, D.
Schubnell, M.
Semenaite, A.
Silber, J.
Sprayberry, D.
Sun, Z.
Tarlé, G.
Weaver, B. A.
Zhou, R.
Zou, H.
Cosmology and Nongalactic Astrophysics
Astrophysics of Galaxies
We present direct measurements of the intrinsic alignments (IA) of over 2 million spectroscopic galaxies using DESI Data Release 1 and imaging from four lensing surveys: DES, HSC, KiDS, and SDSS. In this uniquely data-rich regime, we take initial steps towards a more tailored IA modelling approach by building a library of IA measurements across colour, luminosity, stellar mass, and redshift. We map the dependence between galaxy type -- in terms of rest-frame colour, strength of the 4000 Angstrom break, and specific star formation rate -- and IA amplitude; the bluest galaxies have an alignment consistent with zero, across low ($0.05<z<0.5$) and high ($0.8<z<1.55$) redshifts. In order to construct cosmic shear samples that are minimally impacted by IA but maintain maximum sample size and statistical power, we map the dependence of alignment with colour purity. Red, quenched galaxies are strongly aligned and the amplitude of the signal increases with luminosity, which is tightly correlated with stellar mass in our catalogues. For DESI galaxies between $0<z<1.5$, trends in luminosity and colour alone are sufficient to explain the alignments we measure -- with no need for an explicit redshift dependence. In a companion paper (Jeffrey et al., in prep), we perform detailed modelling of the IA signals with significant detections, including model comparison. Finally, to direct efforts for future IA measurements, we juxtapose the colour-magnitude-redshift coverage of existing IA measurements against modern and future lensing surveys.
title Intrinsic alignment demographics for next-generation lensing: Revealing galaxy property trends with DESI Y1 direct measurements
topic Cosmology and Nongalactic Astrophysics
Astrophysics of Galaxies
url https://arxiv.org/abs/2507.11530