Age-morphology dependence of the Milky Way boxy/peanut bulge seen in Mira variables

Abstract

We analyse the distribution of Mira variable stars in the central region of the Milky Way. We find that with increasing period, i.e. decreasing age, the Miras shift towards negative Galactic longitudes $\ell$. Comparing to a cosmological zoom simulation of a barred galaxy, we find that this shift with age can be explained by an age-morphology dependence of the boxy peanut/bulge. Owing to a combination of projection effects and the limitation of the range of Galactic longitudes, the near hump at $\ell >0$ is more truncated for younger populations, and the far hump at $\ell <0$ dominates the observed distributions.

arXiv comment5 pages, 4 figures, submitted to MNRAS

References in corpus (24)

• E pur si muove: Galiliean-invariant cosmological hydrodynamical simulations on a moving mesh
• The Auriga Project: the properties and formation mechanisms of disc galaxies across cosmic time
• Two Red Clumps and the X-Shaped Milky Way Bulge
• The origin of the split red clump in the Galactic bulge of the Milky Way
• Separation of Stellar Populations by an Evolving Bar: Implications for the Bulge of the Milky Way
• Deciphering the 3D structure of the old Galactic bulge from the OGLE RR Lyrae stars
• Chemodynamics of barred galaxies in cosmological simulations: On the Milky Way's quiescent merger history and in-situ bulge
• Mapping the X-Shaped Milky Way Bulge
• The Gaia-ESO Survey: metallicity and kinematic trends in the Milky Way bulge
• Constraining the structure and formation of the Galactic bulge from a field in its outskirts. FLAMES-GIRAFFE spectra of about 400 red giants around (l,b)=(0°,-10°)
• Gaia Data Release 2: The first Gaia catalogue of long-period variable candidates
• The Frequency and Stellar-Mass Dependence of Boxy/Peanut-Shaped Bulges in Barred Galaxies
• The Age and Structure of the Galactic Bulge from Mira Variables
• Metallicity-dependendent kinematics and morphology of the Milky Way bulge
• Quantifying the (X/Peanut)-Shaped Structure in Edge-on Disc Galaxies: Length, Strength, and Nested Peanuts
• Stars behind bars I: The Milky Way's central stellar populations
• Age Demographics of the Milky Way Disk and Bulge
• The OGLE Collection of Variable Stars. Nearly 66,000 Mira stars in the Milky Way
• Correlations between kinematics and metallicity in the Galactic bulge: a review
• Quantifying the (X/peanut)-shaped Structure of the Milky Way - New Constraints on the Bar Geometry
• Kinematics of RR Lyrae stars in the Galactic bulge with OGLE-IV and Gaia DR2
• Absence of an X-shaped Structure in the Milky Way Bulge Using Mira Variable Stars
• The period-age relation of long-period variables
• The small boxy/peanut structure of the Milky Way traced by old stars

Cited by in corpus (3)

• A three-dimensional map of the Milky Way using 66,000 Mira variable stars
• Hunting for C-rich long-period variable stars in the Milky Way's bar-bulge using unsupervised classification of Gaia BP/RP spectra
• Deciphering the Milky Way disc formation time encrypted in the bar chrono-kinematics