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Main Authors: Hallin, Anna, Shih, David, Krause, Claudius, Buckley, Matthew R.
Format: Preprint
Published: 2025
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Online Access:https://arxiv.org/abs/2509.08064
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author Hallin, Anna
Shih, David
Krause, Claudius
Buckley, Matthew R.
author_facet Hallin, Anna
Shih, David
Krause, Claudius
Buckley, Matthew R.
contents We apply the model-agnostic anomaly detection method Cathode - originally developed for particle physics - to search for stellar streams in Gaia data. We combine Cathode with Via Machinae 3.0: a re-optimized version of the stellar stream detection method that was previously applied to Gaia data together with the related anomaly detection technique Anode. We demonstrate that the combination of Via Machinae 3.0 with Cathode, called VM3-C, not only re-discovers previously known streams, but also confirms many candidate streams identified in combination with Anode (denoted VM3-A). Compared to VM3-A, the number of stream candidates detected by VM3-C increases by around 10%. Moreover, both of the methods discover the same two large clusters of stream candidates in the Northern Galactic hemisphere. We dub these highly significant anomalous structures the Raritan stream and the Passaic stream. These two structures may indicate the presence of larger objects, such as dwarf galaxy streams, or non-trivial orbital dynamics resulting in bifurcation or fanning, and are promising and high-priority targets for further analysis.
format Preprint
id arxiv_https___arxiv_org_abs_2509_08064
institution arXiv
publishDate 2025
record_format arxiv
spellingShingle Via Machinae 3.0: A search for stellar streams in Gaia with the CATHODE algorithm
Hallin, Anna
Shih, David
Krause, Claudius
Buckley, Matthew R.
Astrophysics of Galaxies
High Energy Physics - Phenomenology
We apply the model-agnostic anomaly detection method Cathode - originally developed for particle physics - to search for stellar streams in Gaia data. We combine Cathode with Via Machinae 3.0: a re-optimized version of the stellar stream detection method that was previously applied to Gaia data together with the related anomaly detection technique Anode. We demonstrate that the combination of Via Machinae 3.0 with Cathode, called VM3-C, not only re-discovers previously known streams, but also confirms many candidate streams identified in combination with Anode (denoted VM3-A). Compared to VM3-A, the number of stream candidates detected by VM3-C increases by around 10%. Moreover, both of the methods discover the same two large clusters of stream candidates in the Northern Galactic hemisphere. We dub these highly significant anomalous structures the Raritan stream and the Passaic stream. These two structures may indicate the presence of larger objects, such as dwarf galaxy streams, or non-trivial orbital dynamics resulting in bifurcation or fanning, and are promising and high-priority targets for further analysis.
title Via Machinae 3.0: A search for stellar streams in Gaia with the CATHODE algorithm
topic Astrophysics of Galaxies
High Energy Physics - Phenomenology
url https://arxiv.org/abs/2509.08064