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Week of February 15, 2009 < Back ¦ 2009 ¦ Home

Hot Paper in Physics

"New Hubble Space Telescope discoveries of type Ia supernovae at z [greater than or equal to] 1: Narrowing constraints on the early behavior of dark energy," by Adam G. Riess and 20 others, Astrophysical Journal, 659(1): 98-121, 10 April 2007.

[Authors' affiliations: 10 U.S. institutions]

Abstract: "We have discovered 21 new Type Ia supernovae (SNe Ia) with the Hubble Space Telescope (HST) and have used them to trace the history of cosmic expansion over the last 10 billion yr. These objects, which include 13 spectroscopically confirmed SNe Ia at z >= 1, were discovered during 14 epochs of reimaging of the GOODS fields North and South over 2 yr with the Advanced Camera for Surveys on HST. Together with a recalibration of our previous HST-discovered SNe Ia, the full sample of 23 SNe Ia at z >= 1 provides the highest redshift sample known. Combining these data with previous SN Ia data sets, we measured H (z) at discrete, uncorrelated epochs, reducing the uncertainty of H (z > 1) from 50% to under 20%, strengthening the evidence for a cosmic jerk- the transition from deceleration in the past to acceleration in the present. The unique leverage of the HST high-redshift SNe Ia provides the first meaningful constraint on the dark energy equation-of-state parameter at z >= 1. The result remains consistent with a cosmological constant [w (z) d - 1] and rules out rapidly evolving dark energy (dw/dz > 1). The defining property of dark energy, its negative pressure, appears to be present at z > 1, in the epoch preceding acceleration, with similar to 98% confidence in our primary fit. Moreover, the z > 1 sample-averaged spectral energy distribution is consistent with that of the typical SN Ia over the last 10 Gyr, indicating that any spectral evolution of the properties of SNe Ia with redshift is still below our detection threshold."

This 2007 report from Astrophysical Journal was cited 37 times in current journal articles indexed by Clarivate Analytics during September-October 2008. With its latest two-month total, this is currently the third-most-cited physics paper, aside from reviews, published in the last two years. Prior to the most recent bimonthly count, citations to the paper have accrued as follows:

July-August 2008: 36 citations
May-June 2008: 17
March-April 2008: 22
January-February 2008: 18
November-December 2007: 6
September-October 2007: 17
July-August 2007: 7

Total citations to date: 160

SOURCE: Hot Papers Database (Included with a subscription to the print newsletter Science Watch®, available from the Research Services Group of Thomson Reuters. Packaged on a CD that is mailed with each Science Watch issue, the Hot Papers Database contains data on hundreds of highly cited papers published during the last two years. User interface permits searching by author, organization, journal, field, and more. Total citations, as well as citations accrued during successive bimonthly periods, can be assessed and graphed. An updated CD containing the most recent bimonthly data is mailed with every new issue of Science Watch, six times a year. The CD also includes an electronic version of the Science Watch issue in HTML format, for personal desktop access.

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