Is Liller 1 a building block of the Galactic bulge? -- Evidence with APOGEE

Anna Liptrott; Ricardo P Schiavon; Andrew C Mason; Sebastian Kamann; Borja Anguiano; Roger E Cohen; José G Fernández-Trincado; Danny Horta; Steven R Majewski; Dante Minniti; David M Nataf; Michael J. W O'Connor; Dominic Wearne

doi:10.48550/arxiv.2510.07411

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Is Liller 1 a building block of the Galactic bulge? -- Evidence with APOGEE

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Is Liller 1 a building block of the Galactic bulge? -- Evidence with APOGEE

Anna Liptrott, Ricardo P Schiavon, Andrew C Mason, Sebastian Kamann, Borja Anguiano, Roger E Cohen, José G Fernández-Trincado, Danny Horta, Steven R Majewski, Dante Minniti, …

ArXiv.org

Cornell University

10/08/2025

DOI: 10.48550/arxiv.2510.07411

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Preprint (Author's original)This preprint has not been evaluated by subject experts through peer review. Preprints may undergo extensive changes and/or become peer-reviewed journal articles. Open Access

Abstract

Liller 1 is a stellar system orbiting within the inner 0.8kpc of the Galactic centre, characterised by a wide spread in age and metallicity, indicating a high mass. Liller 1 has been proposed to be a major contributor to the stellar mass of the Galactic bulge, yet its origin is subject to debate. We employ Sloan Digital Sky Survey IV (SDSS-IV) data from the Apache Point Observatory Galactic Evolution Experiment (APOGEE) to test scenarios proposed to explain the nature of Liller 1. Using a random sampling technique, we contrast the chemical compositions of Liller 1 stellar members with those of the bulge, inner disc, outer disk and solar neighbourhood. The chemistry of Liller 1 deviates from that of the bulge population at the 2-3 $σ$level for$α$ -elements Mg, Si, and Ca. We conclude that the progenitor of Liller 1 was not a major contributor of stellar mass to the bulge. Furthermore, we find the abundance pattern of Liller 1 to deviate at the 2 $σ$level from that of inner disk stars, ruling out the cluster rejuvenation scenario. Finally, we find that Liller 1 is chemically distinct from solar and outer disc populations, suggesting that the progenitor of Liller 1 is unlikely to be an in-situ massive clump formed at high redshift, from disc gravitational instabilities, that migrated inwards and coalesced with others into the bulge. Finally, we suggest that Liller 1 is a minor contributor to the stellar mass of the inner Galaxy, possibly of extragalactic origin.

Physics - Astrophysics of Galaxies

Details

Title: Subtitle: Is Liller 1 a building block of the Galactic bulge? -- Evidence with APOGEE
Creators: Anna Liptrott
Ricardo P Schiavon
Andrew C Mason
Sebastian Kamann
Borja Anguiano
Roger E Cohen
José G Fernández-Trincado
Danny Horta
Steven R Majewski
Dante Minniti
David M Nataf
Michael J. W O'Connor
Dominic Wearne
Resource Type: Preprint
Publication Details: ArXiv.org
DOI: 10.48550/arxiv.2510.07411
ISSN: 2331-8422
Publisher: Cornell University; Ithaca, New York
Language: English
Date posted: 10/08/2025
Academic Unit: Physics and Astronomy
Record Identifier: 9985014872502771

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