2018ApJ...865...47Q


C.D.S. - SIMBAD4 rel 1.7 - 2021.01.28CET10:23:45

2018ApJ...865...47Q - Astrophys. J., 865, 47-47 (2018/September-3)

The Mira-based distance to the Galactic Center.

QIN W., NATAF D.M., ZAKAMSKA N., WOOD P.R. and CASAGRANDE L.

Abstract (from CDS):

Mira variables are useful distance indicators, due to their high luminosities and well-defined period-luminosity relation. We select 1863 Miras from SAAO and MACHO observations to examine their use as distance estimators in the Milky Way. We measure a distance to the Galactic center of R0 = 7.9 ± 0.3 kpc, which is in good agreement with other literature values. The uncertainty has two components of ∼0.2 kpc each: the first is from our analysis and predominantly due to interstellar extinction, the second is due to zero-point uncertainties extrinsic to our investigation, such as the distance to the Large Magellanic Cloud (LMC). In an attempt to improve existing period-luminosity calibrations, we use theoretical models of Miras to determine the dependence of the period-luminosity relation on age, metallicity, and helium abundance, under the assumption that Miras trace the bulk stellar population. We find that at a fixed period of logP=2.4, changes in the predicted Ks magnitudes can be approximated by ΔMKs~-0.109(Δ[Fe/H]) + 0.033(Δt/Gyr)+0.021(ΔY/0.01), and these coefficients are nearly independent of period. The expected overestimate in the Galactic center distance from using an LMC-calibrated relation is ∼0.3 kpc. This prediction is not validated by our analysis; a few possible reasons are discussed. We separately show that while the predicted color-color diagrams of solar-neighborhood Miras work well in the near-infrared; though, there are offsets from the model predictions in the optical and mid-infrared.

Abstract Copyright: © 2018. The American Astronomical Society. All rights reserved.

Journal keyword(s): Galaxy: bulge - Galaxy: center - infrared: stars - Magellanic Clouds - stars: AGB and post-AGB - stars: variables: general

Simbad objects: 8

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Number of rows : 8

N Identifier Otype ICRS (J2000)
RA
ICRS (J2000)
DEC
Mag U Mag B Mag V Mag R Mag I Sp type #ref
1850 - 2021
#notes
1 NAME SMC G 00 52 38.0 -72 48 01   2.79 2.2     ~ 9661 1
2 NAME Magellanic Clouds GrG 03 00 -71.0           ~ 5829 1
3 NAME LMC G 05 23 34.6 -69 45 22     0.4     ~ 15129 1
4 NGC 5927 GlC 15 28 00.69 -50 40 22.9   10.13 8.86     ~ 410 0
5 NAME Sgr A* X 17 45 40.03599 -29 00 28.1699           ~ 3581 3
6 NAME Gal Center reg 17 45 40.04 -29 00 28.1           ~ 11938 0
7 [EG97] S2 * 17 45 40.0442 -29 00 27.975           B0/2V 292 1
8 NAME Galactic Bulge reg ~ ~           ~ 3518 0

    Equat.    Gal    SGal    Ecl

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2021.01.28-10:23:46

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