Related papers: H_0 from HST

We introduce a novel way of measuring $H_0$ from a combination of independent geometrical datasets, with no need of calibration nor of the choice of a cosmological model. We build on the {\it distance duality relation} which sets the ratio…

New estimate of the distances of 36 nearby galaxies is presented. It is based on the calibration of the V- and I-band Period-Lumi- nosity relations for galactic Cepheids measured by the HIPPARCOS mission. The distance moduli are obtained in…

The most precise local measurements of $H_0$ rely on observations of Type Ia supernovae (SNe Ia) coupled with Cepheid distances to SN Ia host galaxies. Recent results have shown tension comparing $H_0$ to the value inferred from CMB…

We consider the published distance moduli to the Fornax and Coma galaxy clusters, with emphasis on the period since 1990. We have carefully homogenized our catalogs of distance moduli onto the distance scale established in the previous…

Recent determinations of the Hubble constant, H_0, at extremely low and very high redshifts based on the cosmic distance ladder (grounded with trigonometric parallaxes) and a cosmological model (applied to Planck 2013 data) respectively,…

We present aperture synthesis observations in the 21 cm line of pointings centered on the Virgo Cluster region spirals NGC 4307, NGC 4356, NGC 4411B, and NGC 4492 using the Very Large Array (VLA) radiotelescope in its CS configuration.…

We present the distances of 9792 spiral galaxies lying within 15,000 km/s using the relation between luminosity and rotation rate of spiral galaxies. The sample is dominantly, but not exclusively, drawn from galaxies detected in the course…

The distance modulus of a galaxy determined from Cepheids differs from its distance modulus determined from Tully-Fisher by an amount that is proportional to the galaxy's line width, W: Delta mu ~ (-1.73\pm 0.46)log(W). While a…

This paper summaries the status of a large project to improve distance scales of various classes of variable stars. This is being carried out by a large group in Cape Town, Japan, England and the USA. The results are illustrated by giving…

The direct, empirical determination of the local value of the Hubble constant (H0) has markedly advanced thanks to improved instrumentation, measurement techniques, and distance estimators. However, combining determinations from different…

We present final results of a program for the determination of the Hubble constant based on the calibration of the Type Ia supernovae (SNe Ia) using the Tip of the Red Giant Branch (TRGB). We report TRGB distances to three SN Ia host…

We present an overview of and preliminary results from an ongoing comprehensive program that has a goal of determining the Hubble constant to a systematic accuracy of 2%. As part of this program, we are currently obtaining 3.6 micron data…

The distance to NGC 3319 has been determined from Cepheid variable stars as part of the Hubble Space Telescope Key Project on the Extragalactic Distance Scale. Thirteen and four epochs of observations, using filters F555W (V) and F814W (I)…

Having two "sibling" Type Ia supernovae (SNe Ia) in the same galaxy offers additional advantages in reducing a variety of systematic errors involved in estimating the Hubble constant, $H_{0}$. NGC 4414 is a nearby galaxy included in the…

We present a new calibration of the peak absolute magnitude of SNe Type Ia based on the Surface Brightness Fluctuations (SBF) method, aimed at measuring the value of the Hubble constant. We build a sample of calibrating anchors consisting…

Recent observations of Cepheids in the Virgo cluster have bolstered the evidence that supports a Hubble constant in 70-90 km/s/Mpc range. This evidence, by and large, probes the expansion of the Universe within 100 Mpc. We investigate the…

This is a transcript of a talk that I gave in Cambridge on 17th July 2020 on the `Hubble tension'. I review the SH0ES analyses by Riess and collaborators and point out some internal inconsistencies, including a discrepancy between the…

We present a simultaneous analysis of 18 galaxy lenses with time delay measurements. For each lens we derive mass maps using pixelated simultaneous modeling with shared Hubble constant. We estimate the Hubble constant to be 66_{-4}^{+6}…

The light curve parameters of the normal type Ia SN2011fe are derived from the rich archive of the AAVSO. This leads, together with the TRGB distance modulus of (m-M) = 29.39 +/- 0.05 of the parent galaxy M101, to maximum magnitudes of the…

The distance to NGC 4725 has been derived from Cepheid variables, as part of the Hubble Space Telescope Key Project on the Extragalactic Distance Scale. Thirteen F555W (V) and four F814W (I) epochs of cosmic-ray-split Wide Field and…