z-logo
open-access-imgOpen Access
Clump Giant Distance to the Magellanic Clouds and Anomalous Colors in the Galactic Bulge
Author(s) -
Piotr Popowski
Publication year - 2000
Publication title -
the astrophysical journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 2.376
H-Index - 489
eISSN - 1538-4357
pISSN - 0004-637X
DOI - 10.1086/312426
Subject(s) - red clump , physics , astrophysics , distance modulus , bulge , metallicity , rr lyrae variable , photometry (optics) , absolute magnitude , astronomy , gravitational lens , extinction (optical mineralogy) , red giant branch , large magellanic cloud , cosmic distance ladder , stars , globular cluster , gravitational microlensing , galaxy , redshift , optics
I demonstrate that the two unexpected results in the local universe-(1) anomalous intrinsic (V-I&parr0;0 colors of the clump giants and RR Lyrae stars in the Galactic center, and (2) very short distances to the Magellanic Clouds (LMC, SMC) as inferred from clump giants-are connected with each other. The (V-I&parr0;0 anomaly is partially resolved by using the photometry from phase II of the Optical Gravitational Lensing Experiment (OGLE) rather than phase I. The need for V- or I-magnitude-based change in the bulge (V-I&parr0;0 is one option to explain the remaining color discrepancy. Such a change may originate in a coefficient of selective extinction AV&solm0;E&parl0;V-I&parr0; smaller than typically assumed. Application of the (V-I&parr0;0 correction (independent of its source) doubles the slope of the absolute magnitude-metallicity relation for clump giants, so that MI&parl0;RC&parr0;=-0.23+0.19 [Fe/H]. Consequently, the estimates of the clump distances to the LMC and SMC are affected. Udalski's distance modulus of µLMC=18.18+/-0.06 increases to 18.27+/-0.07. The distance modulus to the SMC increases by 0.12 to µSMC=18.77+/-0.08. I argue that a more comprehensive assessment of the metallicity effect on MI&parl0;RC&parr0; is needed.

The content you want is available to Zendy users.

Already have an account? Click here to sign in.
Having issues? You can contact us here
Accelerating Research

Address

John Eccles House
Robert Robinson Avenue,
Oxford Science Park, Oxford
OX4 4GP, United Kingdom