MEASURING THE HUBBLE CONSTANT WITH THE HUBBLE SPACE TELESCOPE

AbstractTen years ago our team completed the Hubble Space Telescope Key Project on the extragalactic distance scale. Cepheids were detected in some 25 galaxies and used to calibrate four secondary distance indicators that reach out into the expansion field beyond the noise of galaxy peculiar velocities. The result was H0 = 72 ± 8 km s−1 Mpc−1 and put an end to galaxy distances uncertain by a factor of two. This work has been awarded the Gruber Prize in Cosmology for 2009.

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The Hubble Space Telescope Key Project to Measure the Hubble Constant

Symposium - International Astronomical Union ◽

10.1017/s007418090013205x ◽

1999 ◽

Vol 183 ◽

pp. 17-30 ◽

Cited By ~ 13

Author(s):

Wendy L. Freedman ◽

Jeremy R. Mould ◽

Robert C. Kennicutt ◽

Barry F. Madore

Keyword(s):

Hubble Space Telescope ◽

Hubble Constant ◽

Distance Scale ◽

General Assembly ◽

Host Galaxies ◽

Space Telescope ◽

Type Ia Supernova ◽

Type Ia ◽

Extragalactic Distance Scale

A Joint Discussion on the extragalactic distance scale and the Hubble constant took place fifteen years ago, at the 1982 XVIIIth General Assembly of the IAU, held in Patras, Greece. At that time, the newest applications of infrared photometers to Tully-Fisher measurements (Aaronson 1983) and Cepheid distances (Madore 1983) were reported. CCDs were just coming into use and had not yet been applied to extragalactic distance determinations; all of the extragalactic Cepheid distances were based on photographic Argelander (eye-estimated) photometry (Tammann and Sandage 1983 and references therein). No Cepheid distances to type Ia supernova-host galaxies were available.

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Variable Stars and the Cosmic Distance Scale

International Astronomical Union Colloquium ◽

10.1017/s0252921100011507 ◽

1989 ◽

Vol 111 ◽

pp. 169-176

Author(s):

Jeremy Mould

Keyword(s):

Hubble Space Telescope ◽

Hubble Constant ◽

Variable Stars ◽

Virgo Cluster ◽

Distance Scale ◽

Stellar Structure ◽

Space Telescope ◽

Pulsating Variable Stars ◽

Extragalactic Distance Scale ◽

Detector Technology

For three quarters of a century pulsating variable stars have lain at the foundation of the extragalactic distance scale. The construction of larger telescopes, advances in detector technology, hard work by observers, and our understanding of stellar structure have all contributed to the expansion of the realm of the Cepheids to the distance of M101. Now, with the advent of Hubble Space Telescope (HST), we can look forward to the detection of Cepheids in the Virgo cluster and the removal of much of the remaining uncertainty in the Hubble constant.

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Discovery of Cepheids in M100 and M101

Symposium - International Astronomical Union ◽

10.1017/s0074180900109465 ◽

1995 ◽

Vol 164 ◽

pp. 432-433

Author(s):

Jeremy Mould ◽

Wendy Freedman ◽

Laura Ferrarese ◽

Dan Kelson

Keyword(s):

Hubble Space Telescope ◽

Distance Scale ◽

Expansion Rate ◽

Distance Measurements ◽

Space Telescope ◽

Extragalactic Distance Scale ◽

Distance Indicators

The Hubble Space Telescope key project to determine the extragalactic distance scale aims to measure H0 to 10%. To achieve this goal will require Cepheid distance measurements for some 20 galaxies within a redshift of approximately 103 km/s. These galaxies in turn will calibrate five secondary distance indicators which will extend the volume over which the expansion rate has been measured to some 106 Mpc3.

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The Hubble Space Telescope extragalactic distance scale key project. 2: Photometry of WFC images of M81

The Astrophysical Journal ◽

10.1086/174227 ◽

1994 ◽

Vol 428 ◽

pp. 143 ◽

Cited By ~ 9

Author(s):

Shaun M. G. Hughes ◽

Peter B. Stetson ◽

Anne Turner ◽

Robert C., Jr. Kennicutt ◽

Robert Hill ◽

...

Keyword(s):

Hubble Space Telescope ◽

Distance Scale ◽

Space Telescope ◽

Extragalactic Distance Scale

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The Extragalactic Distance Scale Key Project. III. The Discovery of Cepheids and a New Distance to M101 Using the Hubble Space Telescope

The Astrophysical Journal ◽

10.1086/177221 ◽

1996 ◽

Vol 463 ◽

pp. 26 ◽

Cited By ~ 88

Author(s):

Daniel D. Kelson ◽

Garth D. Illingworth ◽

Wendy F. Freedman ◽

John A. Graham ◽

Robert Hill ◽

...

Keyword(s):

Hubble Space Telescope ◽

Distance Scale ◽

Space Telescope ◽

Extragalactic Distance Scale

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The Virgo Cluster

Proceedings of the International Astronomical Union ◽

10.1017/s1743921312021527 ◽

2012 ◽

Vol 8 (S289) ◽

pp. 262-268

Author(s):

Jeremy Mould

Keyword(s):

Hubble Space Telescope ◽

Hubble Constant ◽

Virgo Cluster ◽

Distance Scale ◽

Wilkinson Microwave Anisotropy Probe ◽

Traditional Role ◽

Distance Measurements ◽

Redshift Surveys ◽

Extragalactic Distance Scale

AbstractIn the era of precision cosmology, the Virgo cluster takes on a new role in the cosmic distance scale. Its traditional role of testing the consistency of secondary distance indicators is replaced by an ensemble of distance measurements within the Local Supercluster, united by a velocity-field model obtained from a reconstruction based on redshift surveys. The Wilkinson Microwave Anisotropy Probe (WMAP) leads us to see the Hubble constant as one of six parameters in a standard model of cosmology with considerable covariance among parameters. Independent experiments, such as WMAP, the Hubble Space Telescope Key Project on the Extragalactic Distance Scale, and their successors constrain these parameters.

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The H0 Key Project: Cepheids in NGC925, M101 and M100

International Astronomical Union Colloquium ◽

10.1017/s0252921100037076 ◽

1995 ◽

Vol 155 ◽

pp. 258-259

Author(s):

S. M. G. Hughes

Keyword(s):

Standard Model ◽

Hubble Space Telescope ◽

Big Bang ◽

Distance Scale ◽

Space Telescope ◽

The Standard Model ◽

Age Of The Universe ◽

Extragalactic Distance Scale ◽

The Big Bang ◽

The Universe

AbstractAs part of the Extragalactic Distance Scale Key Project, the Hubble Space Telescope has been used to identify Cepheids in M100, M101 and NGC925, and to measure distances derived from the Cepheid PL relation. For M100, the distance of 17.1 ± 1.8 Mpc has been used to infer a preliminary value for H0 of ~ 80 km/s/Mpc, which brings the age of the Universe derived from the standard model of the Big Bang into conflict with the ages of the oldest stars.

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Progress in Measuring the Hubble Constant

Australian Journal of Physics ◽

10.1071/ph951093 ◽

1995 ◽

Vol 48 (6) ◽

pp. 1093 ◽

Cited By ~ 1

Author(s):

Jeremy Mould

Keyword(s):

Vacuum Energy ◽

Hubble Space Telescope ◽

Hubble Constant ◽

Variable Stars ◽

Space Telescope ◽

Open Universe ◽

Physical Cosmology ◽

Distance Indicators

The Hubble Space Telescope is breaking a long-standing impasse in physical cosmology. The distances of galaxies sufficiently remote for their random velocities to be negligible can now be measured in two steps, the first using Cepheid variable stars as standard candles to approximately 20 Mpc, the second using a variety of secondary distance indicators to distances 10 times larger. The present key project on the Hubble Constant aims to measure Ho to 10%. Current results with approximately 20% uncertainty suggest that cosmologists will be offered a dilemma: an open Universe or a vacuum energy dominated Universe.

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Allan Sandage and the distance scale

Proceedings of the International Astronomical Union ◽

10.1017/s1743921312021059 ◽

2012 ◽

Vol 8 (S289) ◽

pp. 13-25 ◽

Cited By ~ 1

Author(s):

G. A. Tammann ◽

B. Reindl

Keyword(s):

Large Scale ◽

Hubble Space Telescope ◽

Hubble Constant ◽

Distance Scale ◽

Type Ia ◽

The Mean ◽

Red Giant ◽

Ia Supernovae ◽

Distance Indicators ◽

Local Value

AbstractAllan Sandage returned to the distance scale and the calibration of the Hubble constant again and again during his active life, experimenting with different distance indicators. In 1952 his proof of the high luminosity of Cepheids confirmed Baade's revision of the distance scale (H0 ~ 250 km s−1 Mpc−1). During the next 25 years, he lowered the value to 75 and 55. Upon the arrival of the Hubble Space Telescope, he observed Cepheids to calibrate the mean luminosity of nearby Type Ia supernovae (SNe Ia) which, used as standard candles, led to the cosmic value of H0 = 62.3 ± 1.3 ± 5.0 km s−1 Mpc−1. Eventually he turned to the tip of the red giant branch (TRGB) as a very powerful distance indicator. A compilation of 176 TRGB distances yielded a mean, very local value of H0 = 62.9 ± 1.6 km s−1 Mpc−1 and shed light on the streaming velocities in the Local Supercluster. Moreover, TRGB distances are now available for six SNe Ia; if their mean luminosity is applied to distant SNe Ia, one obtains H0 = 64.6 ± 1.6 ± 2.0 km s−1 Mpc−1. The weighted mean of the two independent large-scale calibrations yields H0 = 64.1 km s−1 Mpc−1 within 3.6%.

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