Extending the Stellar-to-Halo Mass Relation to Dwarf Galaxies with DESI DR1
Abstract
Constraining the dark matter halos of the smallest galaxies offers fundamental insights into the nature of dark matter and stellar feedback. Using the Dark Energy Spectroscopic Instrument (DESI) Data Release 1, we infer the stellar-to-halo mass relation (SHMR) down to the dwarf scale (M⋆ < 109 M⊙), without extrapolation from the higher mass range. Leveraging the unprecedented depth of the DESI Bright Galaxy Survey at 0.01 < z < 0.2, we construct 12 samples spanning nearly four orders of magnitude in stellar mass, and measure their projected clustering wp, galaxy-galaxy lensing ΔΣ, as well as a novel observable: satellite occupation number Nsat. The addition of Nsat enables robust subtraction of satellite contributions to both wp and ΔΣ across the 12 individual halo occupation distribution analyses, yielding an average halo-to-stellar mass relation (HSMR) of log ⟨ Mh(M⋆) ⟩ = 12.06 + 0.58log(M⋆/1011) + (M⋆/1011)0.73. Combining this HSMR with an observed stellar mass function, we constrain the SHMR across five orders of magnitude in halo mass, with the power-law slope steepening from 0.32 ± 0.06 above the Milky Way mass to 2.08 ± 0.21 in the dwarf regime. Interestingly, the scatter about the SHMR grows from 0.17 ± 0.02 dex at Milky Way-like scales to 0.68−0.33+0.21 dex for systems comparable to the Large Magellanic Cloud, suggesting that smaller galaxies follow increasingly diverse evolutionary paths. Our work highlights the power of DESI in probing the galaxy-halo connection within the dwarf regime, offering an exciting avenue to bridge the gap between large-scale and near-field cosmologies in the future.
Related
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BibTeX
@misc{shao2026extending,
title = {{Extending the Stellar-to-Halo Mass Relation to Dwarf Galaxies with DESI DR1}},
author = {Zhiwei Shao and Ying Zu and Andrés N Salcedo and Yuanye Lin and Zhao Chen and Xiaoju Xu and Junyu Hua and Zhongxu Zhai and Jessica Nicole Aguilar and Steven Ahlen and Florian Beutler and Davide Bianchi and David Brooks and Aurelio Carnero Rosell and Francisco Javier Castander and Todd Claybaugh and Axel de la Macorra and Biprateep Dey and Zhejie Ding and Jaime E Forero-Romero and Enrique Gaztañaga and Satya Gontcho A. Gontcho and Gaston Gutierrez and Changhoon Hahn and Stephanie Juneau and Robert Kehoe and Anthony Kremin and Ofer Lahav and Andrew Lambert and Martin Landriau and Laurent Le Guillou and Marc Manera and Paul Martini and Aaron Meisner and Ramon Miquel and John Moustakas and Seshadri Nadathur and Enrique Paillas and Will Percival and Francisco Prada and Ignasi Pérez-Ràfols and Corentin Ravoux and Graziano Rossi and Rossana Ruggeri and Manasvee Saraf and Lado Samushia and Eusebio Sanchez and Christoph Saulder and David Schlegel and Joseph Harry Silber and Małgorzata Siudek and Gregory Tarlé and Benjamin Alan Weaver and Hu Zou},
howpublished = {HAL},
year = {2026},
month = sep,
doi = {10.48550/arxiv.2609.04351},
eprint = {2609.04351},
archivePrefix = {arXiv},
url = {https://hal.science/hal-05758204v1},
note = {CC BY 4.0},
}
RIS
TY - UNPB
TI - Extending the Stellar-to-Halo Mass Relation to Dwarf Galaxies with DESI DR1
AU - Zhiwei Shao
AU - Ying Zu
AU - Andrés N Salcedo
AU - Yuanye Lin
AU - Zhao Chen
AU - Xiaoju Xu
AU - Junyu Hua
AU - Zhongxu Zhai
AU - Jessica Nicole Aguilar
AU - Steven Ahlen
AU - Florian Beutler
AU - Davide Bianchi
AU - David Brooks
AU - Aurelio Carnero Rosell
AU - Francisco Javier Castander
AU - Todd Claybaugh
AU - Axel de la Macorra
AU - Biprateep Dey
AU - Zhejie Ding
AU - Jaime E Forero-Romero
AU - Enrique Gaztañaga
AU - Satya Gontcho A. Gontcho
AU - Gaston Gutierrez
AU - Changhoon Hahn
AU - Stephanie Juneau
AU - Robert Kehoe
AU - Anthony Kremin
AU - Ofer Lahav
AU - Andrew Lambert
AU - Martin Landriau
AU - Laurent Le Guillou
AU - Marc Manera
AU - Paul Martini
AU - Aaron Meisner
AU - Ramon Miquel
AU - John Moustakas
AU - Seshadri Nadathur
AU - Enrique Paillas
AU - Will Percival
AU - Francisco Prada
AU - Ignasi Pérez-Ràfols
AU - Corentin Ravoux
AU - Graziano Rossi
AU - Rossana Ruggeri
AU - Manasvee Saraf
AU - Lado Samushia
AU - Eusebio Sanchez
AU - Christoph Saulder
AU - David Schlegel
AU - Joseph Harry Silber
AU - Małgorzata Siudek
AU - Gregory Tarlé
AU - Benjamin Alan Weaver
AU - Hu Zou
PY - 2026
DA - 2026/09/03
PB - HAL
DO - 10.48550/arxiv.2609.04351
UR - https://hal.science/hal-05758204v1
AB - Constraining the dark matter halos of the smallest galaxies offers fundamental insights into the nature of dark matter and stellar feedback. Using the Dark Energy Spectroscopic Instrument (DESI) Data Release 1, we infer the stellar-to-halo mass relation (SHMR) down to the dwarf scale (M_⋆ < 10^9 M_⊙), without extrapolation from the higher mass range. Leveraging the unprecedented depth of the DESI Bright Galaxy Survey at 0.01 < z < 0.2, we construct 12 samples spanning nearly four orders of magnitude in stellar mass, and measure their projected clustering w_p, galaxy-galaxy lensing ΔΣ, as well as a novel observable: satellite occupation number N_sat. The addition of N_sat enables robust subtraction of satellite contributions to both w_p and ΔΣ across the 12 individual halo occupation distribution analyses, yielding an average halo-to-stellar mass relation (HSMR) of log ⟨ M_h(M_⋆) ⟩ = 12.06 + 0.58log(M_⋆/10^11) + (M_⋆/10^11)^0.73. Combining this HSMR with an observed stellar mass function, we constrain the SHMR across five orders of magnitude in halo mass, with the power-law slope steepening from 0.32 ± 0.06 above the Milky Way mass to 2.08 ± 0.21 in the dwarf regime. Interestingly, the scatter about the SHMR grows from 0.17 ± 0.02 dex at Milky Way-like scales to 0.68_−0.33^+0.21 dex for systems comparable to the Large Magellanic Cloud, suggesting that smaller galaxies follow increasingly diverse evolutionary paths. Our work highlights the power of DESI in probing the galaxy-halo connection within the dwarf regime, offering an exciting avenue to bridge the gap between large-scale and near-field cosmologies in the future.
ER -