Consistent calibration of the tip of the red giant branch in the large magellanic cloud on the hubble space telescope photometric system and a redetermination of the hubble constant


Journal Article

© 2019. The American Astronomical Society. All rights reserved. We present a calibration of the tip of the red giant branch (TRGB) in the Large Magellanic Cloud (LMC) on the Hubble Space Telescope (HST)/ACS F814W system. We use archival HST observations to derive blending corrections and photometric transformations for two ground-based wide-Area imaging surveys of the Magellanic Clouds. We show that these surveys are biased bright by up to ∼0.1 mag in the optical due to blending, and that the bias is a function of local stellar density. We correct the LMC TRGB magnitudes from Jang & Lee and use the geometric distance from PietrzyƄski et al.To obtain an absolute TRGB magnitude of MF814W =-3.97 ± 0.046 mag. Applying this calibration to the TRGB magnitudes from Freedman et al. in SN Ia hosts yields a value for the Hubble constant of H 0 = 72.4 ± 2.0 km s-1 Mpc-1 for their TRGB+SNe Ia distance ladder. The difference in the TRGB calibration and the value of H 0 derived here and by Freedman et al. primarily results from their overestimate of the LMC extinction, caused by inconsistencies in their different sources of TRGB photometry for the Magellanic Clouds. Using the same source of photometry (OGLE) for both Clouds and applying the aforementioned corrections yields a value for the LMC I-band TRGB extinction that is lower by 0.06 mag, consistent with independent OGLE reddening maps used by us and by Jang & Lee to calibrate TRGB and determine H 0

Full Text

Duke Authors

Cited Authors

  • Yuan, W; Riess, AG; Macri, LM; Casertano, S; Scolnic, DM

Published Date

  • November 20, 2019

Published In

Volume / Issue

  • 886 / 1

Electronic International Standard Serial Number (EISSN)

  • 1538-4357

International Standard Serial Number (ISSN)

  • 0004-637X

Digital Object Identifier (DOI)

  • 10.3847/1538-4357/ab4bc9

Citation Source

  • Scopus