An updated census of the Vast Polar Structure member galaxies
Abstract
The Vast Polar Structure (VPOS) is a thin, planar arrangement of dwarf galaxies oriented almost perpendicular to the Milky Way (MW) disc. Since its discovery, the census of VPOS member galaxies has progressively expanded thanks to continuous findings of new dwarfs in the vicinity of the MW and increasingly precise measurements of their phase-space coordinates. In this work, we present the largest census to date of VPOS member galaxies, building on a sample of 73 MW dwarfs for which positional and kinematic data are available in the literature. Based on their orbital poles, we identify 22 VPOS members. We note that the majority of VPOS member galaxies are co-rotating, while only three systems are counter-rotating (Bootes III, Kim 1, and Sculptor). Our revised census increases the known VPOS member population by nearly 50%, introducing Delve 4, Kim 1, Kim 3, Eridanus III, Pictor II, and YMCA-1 as new on-plane dwarfs. From this updated census, we revise the structural parameters of the VPOS, confirming its planar (c/a =0.27) and remarkably thin (15 kpc) nature.
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BibTeX
@misc{martinezgarcia2026updated,
title = {{An updated census of the Vast Polar Structure member galaxies}},
author = {Alberto Manuel Martínez-García},
howpublished = {arXiv},
year = {2026},
month = oct,
doi = {10.48550/arxiv.2609.02245},
eprint = {2609.02245},
archivePrefix = {arXiv},
url = {https://arxiv.org/abs/2609.02245},
}
RIS
TY - UNPB
TI - An updated census of the Vast Polar Structure member galaxies
AU - Alberto Manuel Martínez-García
PY - 2026
DA - 2026/10/22
PB - arXiv
DO - 10.48550/arxiv.2609.02245
UR - https://arxiv.org/abs/2609.02245
AB - The Vast Polar Structure (VPOS) is a thin, planar arrangement of dwarf galaxies oriented almost perpendicular to the Milky Way (MW) disc. Since its discovery, the census of VPOS member galaxies has progressively expanded thanks to continuous findings of new dwarfs in the vicinity of the MW and increasingly precise measurements of their phase-space coordinates. In this work, we present the largest census to date of VPOS member galaxies, building on a sample of 73 MW dwarfs for which positional and kinematic data are available in the literature. Based on their orbital poles, we identify 22 VPOS members. We note that the majority of VPOS member galaxies are co-rotating, while only three systems are counter-rotating (Bootes III, Kim 1, and Sculptor). Our revised census increases the known VPOS member population by nearly 50%, introducing Delve 4, Kim 1, Kim 3, Eridanus III, Pictor II, and YMCA-1 as new on-plane dwarfs. From this updated census, we revise the structural parameters of the VPOS, confirming its planar (c/a =0.27) and remarkably thin (15 kpc) nature.
ER -