Results 11 to 20 of about 7,395,903 (283)
Extreme Quasars as Distance Indicators in Cosmology [PDF]
Frontiers in Astronomy and Space Sciences, 2020 Quasars accreting matter at very high rates (known as extreme Population A [xA] quasars, possibly associated with super-Eddington accreting massive black holes) may provide a new class of distance indicators covering cosmic epochs from present day up to ...
Deborah Dultzin +10 more
doaj +8 more sources
Cosmological Distance Indicators [PDF]
Space Science Reviews, 2018 We review three distance measurement techniques beyond the local universe: (1) gravitational lens time delays, (2) baryon acoustic oscillation (BAO), and (3) HI intensity mapping.
S. H. Suyu +3 more
semanticscholar +7 more sources
The Calibration of Novae as Distance Indicators
Astrophysical Journal, 1995 The problem of the correct calibration of the maximum magnitude versus rate of decline relationship for Galactic novae is discussed, on the basis of the properties of the nova populations of M31 and the Large Magellanic Cloud (LMC). We have compared the "observed" maximum magnitude versus rate of decline (hereafter MMRD) distributions of M3 1 and LMC ...
Massimo della Valle
exaly +4 more sources
Gamma-Ray Bursts as Distance Indicators by a Statistical Learning Approach [PDF]
The Astrophysical Journal LettersGamma-ray bursts (GRBs) can be probes of the early Universe, but currently, only 26% of GRBs observed by the Neil Gehrels Swift Observatory have known redshifts ( z ) due to observational limitations.
Maria Giovanna Dainotti +8 more
doaj +2 more sources
The development of accessibility indicators for distance learning programs [PDF]
Research in Learning Technology, 2006 A study was undertaken to explore program policies and practices related to the accessibility of American distance learning courses to qualified students with disabilities.
Sheryl Burgstahler
doaj +2 more sources
Influence of distance from traffic sounds on physiological indicators and subjective evaluation
Transportation Research, Part D: Transport and Environment, 2020 This study examined the influence of different distances of traffic noise and sea sounds on physiological indicators and subjective evaluation. Scene re-creations employed three types of distance: actual close sounds (close to the sound source recorded ...
Jian Kang, Zhongzhe Li
exaly +2 more sources
Young and Intermediate-Age Distance Indicators [PDF]
Space Science Reviews, 2017 Distance measurements beyond geometrical and semi-geometrical methods, rely mainly on standard candles. As the name suggests, these objects have known luminosities by virtue of their intrinsic properties and play a major role in our understanding of ...
S. Subramanian +6 more
semanticscholar +5 more sources
Big Data and Cognitive Computing, 2022 Large retail companies routinely gather huge amounts of customer data, which are to be analyzed at a low granularity. To enable this analysis, several Key Performance Indicators (KPIs), acquired for each customer through different channels are associated
Andrea Ponti +4 more
doaj +3 more sources
Cepheids as Distance Indicators
Annual Review of Astronomy and Astrophysics, 1999 This review attempts to summarize the various ways of determining Cepheid reddenings and luminosities and the zero points of the Cepheid period-luminosity and period-luminosity-color relations. The methods of determining luminosities that are discussed involve Cepheid parallaxes, Cepheid proper motions and radial velocities, Cepheids in clusters and ...
M. Feast, A. R. Walker
semanticscholar +2 more sources
Publications of the Astronomical Society of the Pacific, 1986 From published photographic observations the dispersion in the maximum magnitude versus rate of decline relation for novae in M31 is σ = 0.28 mag, from which the intrinsic dispersion is found to be σ0 < 0.14 mag. This is far smaller than the 1.5 mag range in distance moduli that corresponds to 50 < H < 100 km s-1Mpc-1.
S. van den Bergh, C. Pritchet
semanticscholar +2 more sources