Stellar streams around dwarf galaxies are observationally rare in the local Universe
Abstract
The frequency and properties of stellar streams around dwarf galaxies remain observationally under-explored. Building a statistically significant sample is challenging because dwarf galaxies are smaller, fainter, and far more numerous than massive galaxies. We present the first results from a systematic survey for stellar streams around dwarf galaxies. We first introduce a classification metric for satellite accretion features (streams, shells, and asymmetric stellar haloes) using DECam imaging from the DES and DECaLS surveys. Applying this metric to the DES footprint, we find a low observed frequency of accretion features (5.1%) and no bona fide stellar streams (with only one identified in DECaLS). We consider whether the apparent excess of shells relative to streams can be explained by observational biases. Our results indicate that stellar streams are observationally rare in the local Universe, motivating further theoretical work to determine whether this reflects genuine differences in merger rates across galaxy mass regimes.
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BibTeX
@misc{sakowska2026stellar,
title = {{Stellar streams around dwarf galaxies are observationally rare in the local Universe}},
author = {Joanna D. Sakowska and David Martíınez-Delgado and Sarah Pearson and Francisco J. Riquel-Castilla and Tjitske K. Starkenburg and Giuseppe Donatiello and Alis Deason and Denis Erkal and Ethan D. Taylor},
howpublished = {arXiv},
year = {2026},
month = aug,
doi = {10.48550/arxiv.2608.30806},
eprint = {2608.30806},
archivePrefix = {arXiv},
url = {https://arxiv.org/abs/2608.30806},
note = {CC BY-SA 4.0},
}
RIS
TY - UNPB
TI - Stellar streams around dwarf galaxies are observationally rare in the local Universe
AU - Joanna D. Sakowska
AU - David Martíınez-Delgado
AU - Sarah Pearson
AU - Francisco J. Riquel-Castilla
AU - Tjitske K. Starkenburg
AU - Giuseppe Donatiello
AU - Alis Deason
AU - Denis Erkal
AU - Ethan D. Taylor
PY - 2026
DA - 2026/08/31
PB - arXiv
DO - 10.48550/arxiv.2608.30806
UR - https://arxiv.org/abs/2608.30806
AB - The frequency and properties of stellar streams around dwarf galaxies remain observationally under-explored. Building a statistically significant sample is challenging because dwarf galaxies are smaller, fainter, and far more numerous than massive galaxies. We present the first results from a systematic survey for stellar streams around dwarf galaxies. We first introduce a classification metric for satellite accretion features (streams, shells, and asymmetric stellar haloes) using DECam imaging from the DES and DECaLS surveys. Applying this metric to the DES footprint, we find a low observed frequency of accretion features (5.1%) and no bona fide stellar streams (with only one identified in DECaLS). We consider whether the apparent excess of shells relative to streams can be explained by observational biases. Our results indicate that stellar streams are observationally rare in the local Universe, motivating further theoretical work to determine whether this reflects genuine differences in merger rates across galaxy mass regimes.
ER -