The outer disc in shambles: Blind detection of Monoceros and the ACS with Gaia’s astrometric sample
| Autor: | Teresa Antoja, Cecilia Mateu, Benoit Famaey, Rodrigo A. Ibata, C. F. P. Laporte, Friedrich Anders, J. A. Carballo-Bello, P. Ramos |
|---|---|
| Přispěvatelé: | Institut de cancérologie Paris Nord (ICPN), Observatoire astronomique de Strasbourg (ObAS), Université de Strasbourg (UNISTRA)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS), Ramos P., Antoja T., Mateu Cecilia, Universidad de la República (Uruguay). Facultad de Ciencias. Instituto de Física., Anders F., Laporte C. F. P., Carballo-Bello J. A., Famaey B., Ibata R. |
| Rok vydání: | 2021 |
| Předmět: |
Proper motion
Milky Way kinematics and dynamics -Galaxy halo – astrometry [Galaxy] FOS: Physical sciences Astrophysics::Cosmology and Extragalactic Astrophysics Astrophysics Sagittarius Stream RR Lyrae variable 01 natural sciences Galactic halo 0103 physical sciences formation-Galaxy 010303 astronomy & astrophysics Astrophysics::Galaxy Astrophysics Galaxy rotation curve [PHYS]Physics [physics] Physics 010308 nuclear & particles physics halo -astrometry Astronomy and Astrophysics Astrometry kinematics and dynamics [Galaxy] Astrophysics - Astrophysics of Galaxies Galaxy: halo Galaxy formation [Galaxy] Galaxy: formation Space and Planetary Science Astrophysics of Galaxies (astro-ph.GA) astrometry Astrophysics::Earth and Planetary Astrophysics Halo [PHYS.ASTR]Physics [physics]/Astrophysics [astro-ph] Galaxy: kinematics and dynamics |
| Zdroj: | Astronomy and Astrophysics-A&A Astronomy and Astrophysics-A&A, EDP Sciences, 2021, 646, pp.A99. ⟨10.1051/0004-6361/202039830⟩ Astronomy & Astrophysics COLIBRI Universidad de la República instacron:Universidad de la República |
| ISSN: | 1432-0746 0004-6361 |
| DOI: | 10.1051/0004-6361/202039830 |
| Popis: | The astrometric sample of Gaia allows us to study the outermost Galactic disc, the halo and their interface. It is precisely at the very edge of the disc where the effects of external perturbations are expected to be the most noticeable. Our goal is to detect the kinematic substructure present in the halo and at the edge of the Milky Way (MW) disc, and provide observational constraints on their phase-space distribution. We download, one HEALpix at a time, the proper motion histogram of distant stars, to which we apply a Wavelet Transformation to reveal the significant overdensities. We then analyse the large coherent structures that appear in the sky. We reveal a sharp yet complex anticentre dominated by Monoceros (MNC) and the Anticentre Stream (ACS) in the north, which we find with an intensity comparable to the Magellanic clouds and the Sagittarius stream, and by MNC south and TriAnd at negative latitudes. Our method allows us to perform a morphological analysis of MNC and ACS, both spanning more than 100$^\circ$ in longitude, and to provide a high purity sample of giants with which we track MNC down to latitudes as low as $\sim$5$^\circ$. Their colour-magnitude diagram is consistent with extended structures at a distance of $\sim$10-11 kpc originated in the disc, with a very low ratio of RR Lyrae over M giants, and kinematics compatible with the rotation curve at those distances or only slightly slower. We present a precise characterisation of MNC and ACS, two previously known structures that our method reveals naturally, allowing us to detect them without limiting ourselves to a particular stellar type and, for the first time, using only kinematics. Our results allow future studies to model their chemo-dynamics and evolution, thus constraining some of the most influential processes that shaped the MW. Submitted to Astronomy and Astrophysics. Online material available upon acceptance |
| Databáze: | OpenAIRE |
| Externí odkaz: |
|