Bibcode
López-Corredoira, M.
Bibliographical reference
Astronomy and Astrophysics, Volume 593, id.A66, 9 pp.
Advertised on:
9
2016
Journal
Citations
13
Refereed citations
11
Description
Context. A number of recent papers have claimed the discovery of an
X-shape structure in the bulge of our Galaxy in the population of the
red clumps. Aims: We endeavor to analyze the stellar density of
bulge stars in the same regions using a different stellar population
that is characteristic of the young bulge (≲ 5 Gyr). Particularly,
we use F0-F5 main-sequence stars with distances derived through
photometric parallax. Methods: We extract these stars from
extinction-corrected color-magnitude diagrams in the near-infrared of
VISTA-VVV data in some bulge regions and calculate the densities along
the line of sight. We take the uncertaintity in the photometric parallax
and the contamination of other sources into account, and we see that
these errors do not avoid the detection of a possible double peak along
some lines of sight as expected for a X-shape bulge if it existed. Results: Only a single peak in the density distribution along the
line of sight is observed, so apparently there is no X-shape structure
for this population of stars. Nonetheless, the effects of the dispersion
of absolute magnitudes in the selected population might be an
alternative explanation, although in principle these effects are
insufficient to explain this lack of double peak according to our
calculations. Conclusions: The results of the present paper do
not demonstrate that previous claims of X-shaped bulge using only red
clump stars are incorrect, but there are apparently some puzzling
questions if we want to maintain the validity of both the red-clump
results and the results of this paper.