Semiresolved Stellar Populations as Distance Indicators

Martín-Navarro, Ignacio; Iglesias Navarro, Patricia; La Barbera, Francesco; Vazdekis, Alexandre; Beasley, Michael A.; Huertas-Company, Marc; Hahn, ChangHoon; Peralta de Arriba, Luis; Alonso Asensio, Isaac; Angeloudi, Eirini; Cerviño, Miguel; Fahrion, Katja; Jerabkova, Tereza; Falcón-Barroso, Jesús; Sánchez, Sebastián F.; Jethwa, Prashin
Bibliographical reference

The Astrophysical Journal Letters

Advertised on:
8
2026
Number of authors
16
IAC number of authors
9
Citations
0
Refereed citations
0
Description
Galaxy distances are central to our understanding of the Universe. Despite the success of existing approaches, independent and complementary methods remain valuable for testing systematic effects and extending the applicability range of different distance metrics. Here we demonstrate that the spectrum of an individual semiresolved stellar population encodes direct information about its distance and that valuable distance constraints can, in principle, be obtained by combining multiple independent measurements. When applied to optical spectra of bulge of the Andromeda galaxy (M31), we derive a stellar population─based distance of 756 ± 57 kpc (μ0 = 24.39 ± 0.15), in agreement with state-of-the-art measurements. Crucially, semiresolved stellar population distances do not require secondary calibrations, although its absolute scale remains conditional on the adopted stellar population models. Our findings provide a first assessment of the feasibility of deriving stellar population─based distance estimates from simple stellar population models, motivating further tests of the broader applicability and precision of the method.