Results 11 to 20 of about 1,848 (175)
Easing the Hubble constant tension [PDF]
Modern Physics Letters A, 2022 In this paper, we show how a modified Friedmann equation, originating from a model of the universe built from a certain [Formula: see text] algebra, has the potential to explain the difference between the Hubble constants extracted from CMB data and from supernova data.
Ambjørn, Jan, Watabiki, Y.
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Determination of the Hubble constant. [PDF]
Proc Natl Acad Sci U S A, 1999 Establishing accurate extragalactic distances has provided an immense challenge to astronomers since the 1920s. The situation has improved dramatically as better detectors have become available, and as several new, promising techniques have been developed. For the first time in the history of this difficult field, relative distances to
Freedman WL, Feng LL.
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CATS: The Hubble Constant from Standardized TRGB and Type Ia Supernova Measurements
The Astrophysical Journal Letters, 2023 The tip of the red giant branch (TRGB) provides a luminous standard candle for constructing distance ladders to measure the Hubble constant. In practice, its measurements via edge-detection response (EDR) are complicated by the apparent fuzziness of the ...
D. Scolnic +9 more
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DETERMINING THE HUBBLE CONSTANT FROM HUBBLE PARAMETER MEASUREMENTS [PDF]
The Astrophysical Journal, 2017 Abstract We use 28 measurements of the Hubble parameter, H(z), at intermediate redshifts to determine the present-day Hubble constant H 0 in four cosmological models. We measure , and
Yun Chen, Suresh Kumar, Bharat Ratra
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Andromeda’s Parachute: Time Delays and Hubble Constant
The Astrophysical Journal, 2023 The gravitational lens system PS J0147+4630 (Andromeda’s Parachute) consists of four quasar images ABCD and a lensing galaxy. We obtained r -band light curves of ABCD in the 2017−2022 period from monitoring with two 2 m class telescopes.
Vyacheslav N. Shalyapin +3 more
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Acta Physica Sinica, 2023 The Hubble constant quantitatively characterizes the expansion rate of the current Universe, and its precise measurement has become a crucial scientific problem. In recent years, there has been an increasingly serious discrepancy between the local direct measurements of the Hubble constant and the global fitting results, where the local direct ...
Rong-Gen CAI, Li LI, Shao-Jiang WANG
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Proc Natl Acad Sci U S A, 1993 Five methods of estimating distances have demonstrated internal reproducibility at the level of 5-20% rms accuracy. The best of these are the cepheid (and RR Lyrae), planetary nebulae, and surface-brightness fluctuation techniques. Luminosity-line width and Dn-sigma methods are less accurate for an individual case but can be applied to large numbers of
Tully RB.
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Annual Review of Astronomy and Astrophysics, 2010 Considerable progress has been made in determining the Hubble constant over the past two decades. We discuss the cosmological context and importance of an accurate measurement of the Hubble constant, focusing on six high-precision distance-determination methods: Cepheids, tip of the red giant branch, maser galaxies, surface brightness fluctuations, the
Freedman, Wendy L., Madore, Barry F.
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The Astrophysical Journal Letters, 2023 We establish a cosmological-model-independent method to determine the Hubble constant H _0 from the localized fast radio bursts (FRBs) and the Hubble parameter measurements from cosmic chronometers and obtain a first such determination H _0 = 71 ± 3 km s
Yang Liu, Hongwei Yu, Puxun Wu
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The Unsettled Number: Hubble’s Tension
Universe, 2023 One of main sources of uncertainty in modern cosmology is the present rate of the universe’s expansion, H0, called the Hubble constant. Once again, different observational techniques bring about different results, causing new “Hubble tension”.
Jorge L. Cervantes-Cota +2 more
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