Cosmic Rulers: Masers as Tools for Probing Structure in the Galaxy and Beyond, from AU to kpc

Kazi L. J. Rygl; Anna Bartkiewicz; Olga Bayandina; Andreas Brunthaler; Sandra Etoka; Simon Ellingsen; Dieter Engels; Tomoya Hirota; Arshia Maria Jacob; Jacco Th. van Loon; Alberto Sanna; Lucero Uscanga

arXiv · 2606.31237

Cosmic Rulers: Masers as Tools for Probing Structure in the Galaxy and Beyond, from AU to kpc

Kazi L. J. Rygl·Anna Bartkiewicz·Olga Bayandina·Andreas Brunthaler·Sandra Etoka·Simon Ellingsen·Dieter Engels·Tomoya Hirota·Arshia Maria Jacob·Jacco Th. van Loon·Alberto Sanna·Lucero Uscanga

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Abstract

Maser emission provides an unique window into astronomical sources across vast spatial scales - from tens to hundreds of astronomical units around protostars and evolved stars up to kiloparsecs in distant galaxies. These natural microwave amplifiers penetrate dust shells in star-forming regions, revealing the dynamics of accretion disks and outflows, trace envelopes and winds of evolved stars, map Galactic structure, while also allowing us to follow the evolution of all these systems. Owing to their compactness and brightness masers provide precise astrometry as cosmic rulers: measuring positions, structures and kinematics in dense regions, not easily accessible at other wavelengths. SKA-Mid will observe hydroxyl, methanol, and formaldehyde masers using bands 2, 5a and 5b, and later methylidyne radical masers in band 4. SKA-Mid's sensitivity and broad frequency coverage will support discoveries of new maser types and allow for simultaneous multi-transition and multi-species maser observations. In addition, bright masers can serve in the science verification of the SKA-Mid array during the deployment phase.

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Kazi L. J. Rygl, Anna Bartkiewicz, Olga Bayandina, Andreas Brunthaler, Sandra Etoka, Simon Ellingsen, Dieter Engels, Tomoya Hirota, Arshia Maria Jacob, Jacco Th. van Loon, Alberto Sanna, Lucero Uscanga. 2026-06-30. Cosmic Rulers: Masers as Tools for Probing Structure in the Galaxy and Beyond, from AU to kpc. https://arxiv.org/abs/2606.31237

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