%0 Generic %1 yuan2019consistent %A Yuan, Wenlong %A Riess, Adam G. %A Macri, Lucas M. %A Casertano, Stefano %A Scolnic, Dan %D 2019 %K tifr %T Consistent Calibration of the Tip of the Red Giant Branch in the Large Magellanic Cloud on the Hubble Space Telescope Photometric System and Implications for the Determination of the Hubble Constant %U http://arxiv.org/abs/1908.00993 %X The tip of the red giant branch (TRGB) is a promising standard candle for measuring extragalactic distances, but inaccuracies between ground and Hubble Space Telescope (HST) system photometry used in its absolute calibration currently limit its potential. We present the calibration of the TRGB in the Large Magellanic Cloud (LMC) on the HST/ACS F814W system. We used archival HST observations of 12 fields in the LMC to derive blending corrections and photometric transformations for two comparatively low-resolution, ground-based wide-area imaging surveys of the LMC that are frequently used to measure the TRGB. We show that measurements of the TRGB in the LMC and in the Small Magellanic Cloud (SMC) based on these surveys are biased (too bright) by up to ~0.1 mag in the optical due to blending, and that the bias is a function of local stellar density. The ground-to-HST correction enables us to place the LMC TRGB zeropoint on the ACS F814W system, which is commonly used for extragalactic calibrations, while benefiting from the large sample of TRGB stars from ground-based observations. We applied the ground-to-HST corrections to the LMC TRGB magnitudes from Jang & Lee (2017) and obtained an extinction-corrected TRGB magnitude of I_0=14.507+- 0.012 (stat) +- 0.028 (sys) mag on the ACS F814W system. Using the geometric distance from Pietrzynski et al. (2019), this corresponds to an absolute TRGB magnitude of M_F814W=-3.97 +- 0.04 mag. We revisited the method used by Freedman et al. (2019) to determine the extinction of the TRGB in the LMC after accounting for the blending measured in the LMC and SMC ground photometry. We found that blending in their adopted SMC TRGB photometry (from Zaritsky et al. 2002) caused a ~0.06 mag overestimate of the LMC extinction in the I band. We determine a value for the Hubble constant of H_0=72.4 +- 1.9 km/s/Mpc for the TRGB+SNe~Ia distance ladder.

@misc{yuan2019consistent, abstract = {The tip of the red giant branch (TRGB) is a promising standard candle for measuring extragalactic distances, but inaccuracies between ground and Hubble Space Telescope (HST) system photometry used in its absolute calibration currently limit its potential. We present the calibration of the TRGB in the Large Magellanic Cloud (LMC) on the HST/ACS F814W system. We used archival HST observations of 12 fields in the LMC to derive blending corrections and photometric transformations for two comparatively low-resolution, ground-based wide-area imaging surveys of the LMC that are frequently used to measure the TRGB. We show that measurements of the TRGB in the LMC and in the Small Magellanic Cloud (SMC) based on these surveys are biased (too bright) by up to ~0.1 mag in the optical due to blending, and that the bias is a function of local stellar density. The ground-to-HST correction enables us to place the LMC TRGB zeropoint on the ACS F814W system, which is commonly used for extragalactic calibrations, while benefiting from the large sample of TRGB stars from ground-based observations. We applied the ground-to-HST corrections to the LMC TRGB magnitudes from Jang & Lee (2017) and obtained an extinction-corrected TRGB magnitude of I_0=14.507+- 0.012 (stat) +- 0.028 (sys) mag on the ACS F814W system. Using the geometric distance from Pietrzynski et al. (2019), this corresponds to an absolute TRGB magnitude of M_F814W=-3.97 +- 0.04 mag. We revisited the method used by Freedman et al. (2019) to determine the extinction of the TRGB in the LMC after accounting for the blending measured in the LMC and SMC ground photometry. We found that blending in their adopted SMC TRGB photometry (from Zaritsky et al. 2002) caused a ~0.06 mag overestimate of the LMC extinction in the I band. We determine a value for the Hubble constant of H_0=72.4 +- 1.9 km/s/Mpc for the TRGB+SNe~Ia distance ladder.}, added-at = {2019-08-06T06:16:25.000+0200}, author = {Yuan, Wenlong and Riess, Adam G. and Macri, Lucas M. and Casertano, Stefano and Scolnic, Dan}, biburl = {https://www.bibsonomy.org/bibtex/2b5e845ecf93cbe9d158e0eb7654eea7b/citekhatri}, description = {Consistent Calibration of the Tip of the Red Giant Branch in the Large Magellanic Cloud on the Hubble Space Telescope Photometric System and Implications for the Determination of the Hubble Constant}, interhash = {9dfccd91f9ed03ff9c7f7ed97dcb7fe6}, intrahash = {b5e845ecf93cbe9d158e0eb7654eea7b}, keywords = {tifr}, note = {cite arxiv:1908.00993Comment: Submitted to ApJ}, timestamp = {2019-08-06T06:16:25.000+0200}, title = {Consistent Calibration of the Tip of the Red Giant Branch in the Large Magellanic Cloud on the Hubble Space Telescope Photometric System and Implications for the Determination of the Hubble Constant}, url = {http://arxiv.org/abs/1908.00993}, year = 2019 }