2020ApJ...889...56N -
Astrophys. J., 889, 56-56 (2020/January-3)
VVV survey microlensing: the Galactic latitude dependence.
NAVARRO M.G., MINNITI D., PULLEN J. and CONTRERAS RAMOS R.
Abstract (from CDS):
We search for microlensing events in fields along the Galactic minor axis, ranging from the Galactic center to -3.°7 < b < 3.°9 using the VISTA Variables in the Via Lactea (VVV) survey near-IR photometry. The new search is made across VVV tiles b291, b305, b319, b347, b361, and b375, covering a total area of about 11.5 deg2. We find a total of N = 238 new microlensing events in this new area, N = 74, which are classified as bulge red clump (RC) giant sources. Combining them with N = 122 events that we had previously reported in the Galactic center (VVV tile b333), allows us to study the latitude distribution of the microlensing events reaching the Galactic plane at b = 00 for the first time. We find a very strong dependence of the number of microlensing events with Galactic latitude, a number that increases rapidly toward the Galactic center by one order of magnitude from | b| =2° to b = 0° with a much steeper gradient than with Galactic longitude. The microlensing event population shows a flattened distribution (axial ratio b/a ≃ 1.5). The final sample shows a shorter mean timescale distribution than the Galactic plane sample for both the complete population and RC stars.
Abstract Copyright:
© 2020. The American Astronomical Society. All rights reserved.
Journal keyword(s):
Galactic bulge - Milky Way Galaxy physics - Galaxy structure - Gravitational microlensing - Gravitational lensing - Galactic center
VizieR on-line data:
<Available at CDS (J/ApJ/889/56): table2.dat>
Simbad objects:
237
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