English (United Kingdom)

https://curated-unify.zendy.io/wp-json/zendy-region/v1/featured_content/oa?rat=en

https://curated-unify.zendy.io/wp-json/zendy-region/v1/highlighted_journal/

Global: Zendy Plus annual

Presents the access of premium content as premium feature

Premium Content

Presents the keyphrase highlighting as premium feature

Keyphrase Highlighting

Presents the summarisation as premium feature

Summarisation

Insights

Presents the pdf analysis as premium feature

PDF Analysis

Presents the zaia usage as premium feature

ZAIA

Global: Zendy Tools annual

Global: Zendy Free Plan

Global: Zendy Tools monthly

Global: Zendy Plus monthly

The tip of the red giant branch has been used to measure distances to 500nearby galaxies with the Hubble Space Telescope (HST) which are available inthe Color-Magnitude Diagrams and Tip of the Red Giant Branch (CMDs/TRGB)catalog on the Extragalactic Distance Database (EDD). Our established methodsare employed to perform an independent reduction of the targets presented bythe Carnegie-Chicago Hubble Program (CCHP) in the series of papers culminatingin Freedman (2021). Our distinct methodology involves modeling the observedluminosity function of red giant branch and asymptotic giant branch stars,which differs from the edge-detection algorithms employed by the CCHP. We findexcellent agreement between distances for 11 hosts with new imaging, all at D <20 Mpc. However, we are unable to measure the TRGB for 4 of the 5 hosts thatuse archival data designed to measure distances with Cepheids, all at D > 23Mpc. With two new HST observations taken in the halo of the megamaser host NGC4258, the first with the same ACS F606W and F814W filters and thepost-servicing electronics used for SN Ia hosts, we then calibrate our TRGBdistance scale to the geometric megamaser distance. Using our TRGB distances,we find a value of the Hubble Constant of $H_{0}$ = 71.5 $\pm$ 1.8 km/s/Mpcwhen using either the Pantheon or Carnegie Supernova Project (CSP) samples ofsupernovae. In the future, the James Webb Space Telescope will extendmeasurements of the TRGB to additional hosts of SN Ia and surface brightnessfluctuation measurements for separate paths to $H_{0}$.

astrophysical journal/the astrophysical journal

Comparing Tip of the Red Giant Branch Distance Scales: An Independent  Reduction of the Carnegie-Chicago Hubble Program and the Value of the Hubble  Constant