Signatures of a tidally induced spiral arm at the anticenter of the milky way and a kinematically extended anticenter stream using DESI data release 2

Using the Dark Energy Spectroscopic Instrument (DESI) Milky Way Survey, we examine the six-dimensional space of the anticenter region of the Milky Way stellar disk (150° < Galactic longitude < 220°) using 61,883 main-sequence turnoff stars. We focus on two well-known stellar overdensities in t...

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Detalles Bibliográficos
Autores: Lambert, Mika|||0000-0002-2527-8899, Rockosi, Constance|||0000-0002-6667-7028, Koposov, Sergey E.|||0000-0003-2644-135X, Li, Ting S.|||0000-0002-9110-6163, Valluri, Monica|||0000-0002-6257-2341, Beraldo e Silva, Leandro|||0000-0002-0740-1507, Li, Songting|||0000-0002-6469-8263, Pérez Ràfols, Ignasi|||0000-0001-6979-0125
Tipo de recurso: artículo
Fecha de publicación:2026
País:España
Institución:Universitat Politècnica de Catalunya (UPC)
Repositorio:UPCommons. Portal del coneixement obert de la UPC
Idioma:inglés
OAI Identifier:oai:dnet:upcommonspor::1ebb3400734f6a3e9d3a94290559ec2c
Acceso en línea:https://hdl.handle.net/2117/461462
https://dx.doi.org/10.3847/1538-3881/ae5100
Access Level:acceso abierto
Palabra clave:Galaxies
Milky Way
Galàxies
Via Làctia
Àrees temàtiques de la UPC::Física::Astronomia i astrofísica
Descripción
Sumario:Using the Dark Energy Spectroscopic Instrument (DESI) Milky Way Survey, we examine the six-dimensional space of the anticenter region of the Milky Way stellar disk (150° < Galactic longitude < 220°) using 61,883 main-sequence turnoff stars. We focus on two well-known stellar overdensities in the anticenter: the Monoceros Ring (MRi) and Anticenter Stream (ACS). We find that the MRi overdensity has kinematic signatures consistent with a tidally induced spiral arm, a type of dynamic spiral arm created by an interaction with a satellite galaxy, most likely the Sagittarius dwarf spheroidal galaxy (Sgr). We use the kinematics of the MRi to calculate the two most recent passage times of Sgr, finding 0.25 ± 0.09 Gyr and 1.10 ± 0.23 Gyr from the present day. We validate that the ACS is kinematically decoupled from the MRi because they are moving in opposite radial and vertical directions. We find that the kinematics associated with the ACS extends beyond our defined overdensity. The features we see in the ACS region are likely part of a broader distribution of stars with the same kinematic signature as detected in other places, like the vertical wave in the outer disk and phase spiral.

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