Query : 2022A&A...666L..13C

2022A&A...666L..13C - Astronomy and Astrophysics, volume 666, L13 (2022/10-1)

Analysing the structure of the bulge with Mira variables.


Abstract (from CDS):

Context. The Galactic bulge at latitude 4 < |b|(deg) < 10 was claimed to show an X-shape, which means that stellar density distributions along the line of sight have a double peak. However, this double peak is only observed with the red-clump population, and doubt has been cast on its use as a perfect standard candle. As such, a boxy bulge without an X-shape is not discarded.
Aims. We aim to constrain the shape of the bulge making use of a different population: Mira variables from the new Optical Gravitational Lensing Experiment data release, OGLE-IV, with an average age of 9 Gyr.
Methods. We analysed an area of the bulge far from the plane, where we fitted the density of the Miras with boxy bulge and X-shaped bulge models and calculated the probability of each model.
Results. We find that the probability of a boxy bulge fitting the data is p = 0.19, whereas the probability for the X-shaped bulge is only p = 2.85 × 10–6 (equivalent to a tension of the model with the data of a 4.7σ level). Therefore, the boxy bulge model seems to be more appropriate for describing the Galactic bulge, although we cannot exclude any model with complete certainty.

Abstract Copyright: © Ž. Chrobáková et al. 2022

Journal keyword(s): Galaxy: bulge

Simbad objects: 2

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Number of rows : 2
N Identifier Otype ICRS (J2000)
ICRS (J2000)
Mag U Mag B Mag V Mag R Mag I Sp type #ref
1850 - 2024
1 NAME Galactic Center reg 17 45 39.60213 -29 00 22.0000           ~ 14463 0
2 NAME Galactic Bulge reg ~ ~           ~ 4309 0

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