Systematic Errors in the Hubble Constant Based upon Measurement of the Sunyaev‐Zeldovich Effect

1997 ◽  
Vol 482 (2) ◽  
pp. 588-603 ◽  
Author(s):  
Kurt Roettiger ◽  
James M. Stone ◽  
Richard F. Mushotzky
Keyword(s):  
Hubble Constant ◽  
Systematic Errors

scholarly journals Systematic Errors in the Hubble Constant Measurement from the Sunyaev‐Zel’dovich Effect

2008 ◽  
Vol 674 (1) ◽  
pp. 11-21 ◽  
Author(s):  
Hajime Kawahara ◽  
Tetsu Kitayama ◽  
Shin Sasaki ◽  
Yasushi Suto
Keyword(s):  
Hubble Constant ◽  
Systematic Errors ◽  
Constant Measurement ◽  
Sunyaev Zel'dovich Effect

scholarly journals A measurement of the Hubble constant from Type II supernovae

2020 ◽  
Vol 496 (3) ◽  
pp. 3402-3411 ◽  
Author(s):  
T de Jaeger ◽  
B E Stahl ◽  
W Zheng ◽  
A V Filippenko ◽  
A G Riess ◽  
...  
Keyword(s):  
Cold Dark Matter ◽  
Background Radiation ◽  
Hubble Constant ◽  
Systematic Errors ◽  
Host Galaxy ◽  
Microwave Background Radiation ◽  
Type Ia ◽  
Cepheid Variables ◽  
Red Giant ◽  
Ia Supernovae

ABSTRACT Progressive increases in the precision of the Hubble-constant measurement via Cepheid-calibrated Type Ia supernovae (SNe Ia) have shown a discrepancy of ∼4.4σ with the current value inferred from Planck satellite measurements of the cosmic microwave background radiation and the standard $\Lambda $cold dark matter (ΛCDM) cosmological model. This disagreement does not appear to be due to known systematic errors and may therefore be hinting at new fundamental physics. Although all of the current techniques have their own merits, further improvement in constraining the Hubble constant requires the development of as many independent methods as possible. In this work, we use SNe II as standardisable candles to obtain an independent measurement of the Hubble constant. Using seven SNe II with host-galaxy distances measured from Cepheid variables or the tip of the red giant branch, we derive H$_0= 75.8^{+5.2}_{-4.9}$ km s−1 Mpc−1 (statistical errors only). Our value favours that obtained from the conventional distance ladder (Cepheids + SNe Ia) and exhibits a difference of 8.4 km s−1 Mpc−1 from the Planck + ΛCDM value. Adding an estimate of the systematic errors (2.8 km s−1 Mpc−1) changes the ∼1.7σ discrepancy with Planck +ΛCDM to ∼1.4σ. Including the systematic errors and performing a bootstrap simulation, we confirm that the local H0 value exceeds the value from the early Universe with a confidence level of 95 per cent. As in this work, we only exchange SNe II for SNe Ia to measure extragalactic distances, we demonstrate that there is no evidence that SNe Ia are the source of the H0 tension.

Test of the cosmic transparency with the standard candles and the standard ruler

2018 ◽  
Vol 27 (05) ◽  
pp. 1850054 ◽  
Author(s):  
Jun Chen
Keyword(s):  
Observational Data ◽  
Confidence Level ◽  
Free Parameter ◽  
Hubble Constant ◽  
Systematic Errors ◽  
Acoustic Oscillation ◽  
Independent Method ◽  
Baryon Acoustic Oscillation ◽  
Type Ia ◽  
Model Independent

In this paper, the cosmic transparency is constrained by using the latest baryon acoustic oscillation (BAO) data and the type Ia supernova data with a model-independent method. We find that a transparent universe is consistent with observational data at the [Formula: see text] confidence level, except for the case of BAO+ Union 2.1 without the systematic errors where a transparent universe is favored only at the [Formula: see text] confidence level. To investigate the effect of the uncertainty of the Hubble constant on the test of the cosmic opacity, we assume [Formula: see text] to be a free parameter and obtain that the observations favor a transparent universe at the [Formula: see text] confidence level.

Statistics and parallaxes

1978 ◽  
Vol 48 ◽  
pp. 7-29
Author(s):  
T. E. Lutz
Keyword(s):  
Experimental Design ◽  
Statistical Methods ◽  
Review Paper ◽  
Systematic Errors ◽  
Past Experience ◽  
Random Errors ◽  
Trigonometric Parallaxes ◽  
Systematic And Random Errors

This review paper deals with the use of statistical methods to evaluate systematic and random errors associated with trigonometric parallaxes. First, systematic errors which arise when using trigonometric parallaxes to calibrate luminosity systems are discussed. Next, determination of the external errors of parallax measurement are reviewed. Observatory corrections are discussed. Schilt’s point, that as the causes of these systematic differences between observatories are not known the computed corrections can not be applied appropriately, is emphasized. However, modern parallax work is sufficiently accurate that it is necessary to determine observatory corrections if full use is to be made of the potential precision of the data. To this end, it is suggested that a prior experimental design is required. Past experience has shown that accidental overlap of observing programs will not suffice to determine observatory corrections which are meaningful.

Dielectronic Recombination in the Average-Atom Model

1988 ◽  
Vol 102 ◽  
pp. 215
Author(s):  
R.M. More ◽  
G.B. Zimmerman ◽  
Z. Zinamon
Keyword(s):  
Detailed Balance ◽  
Systematic Errors ◽  
Dielectronic Recombination ◽  
Rate Equations ◽  
Strong Correlations ◽  
Dense Plasmas ◽  
Atom Model ◽  
New Feature ◽  
Average Atom Model ◽  
Attachment Process

Autoionization and dielectronic attachment are usually omitted from rate equations for the non–LTE average–atom model, causing systematic errors in predicted ionization states and electronic populations for atoms in hot dense plasmas produced by laser irradiation of solid targets. We formulate a method by which dielectronic recombination can be included in average–atom calculations without conflict with the principle of detailed balance. The essential new feature in this extended average atom model is a treatment of strong correlations of electron populations induced by the dielectronic attachment process.

Precise on-line Measurement of Lattice Vectors

1990 ◽  
Vol 48 (1) ◽  
pp. 530-531
Author(s):  
W.J. de Ruijter ◽  
Sharma Renu
Keyword(s):  
Electron Microscope ◽  
Measurement Errors ◽  
Dynamic Range ◽  
Structural Information ◽  
Statistical Parameter ◽  
Systematic Errors ◽  
Geometric Distortion ◽  
Crystal Silicon ◽  
Camera System ◽  
On Line

Established methods for measurement of lattice spacings and angles of crystalline materials include x-ray diffraction, microdiffraction and HREM imaging. Structural information from HREM images is normally obtained off-line with the traveling table microscope or by the optical diffractogram technique. We present a new method for precise measurement of lattice vectors from HREM images using an on-line computer connected to the electron microscope. It has already been established that an image of crystalline material can be represented by a finite number of sinusoids. The amplitude and the phase of these sinusoids are affected by the microscope transfer characteristics, which are strongly influenced by the settings of defocus, astigmatism and beam alignment. However, the frequency of each sinusoid is solely a function of overall magnification and periodicities present in the specimen. After proper calibration of the overall magnification, lattice vectors can be measured unambiguously from HREM images.Measurement of lattice vectors is a statistical parameter estimation problem which is similar to amplitude, phase and frequency estimation of sinusoids in 1-dimensional signals as encountered, for example, in radar, sonar and telecommunications. It is important to properly model the observations, the systematic errors and the non-systematic errors. The observations are modelled as a sum of (2-dimensional) sinusoids. In the present study the components of the frequency vector of the sinusoids are the only parameters of interest. Non-systematic errors in recorded electron images are described as white Gaussian noise. The most important systematic error is geometric distortion. Lattice vectors are measured using a two step procedure. First a coarse search is obtained using a Fast Fourier Transform on an image section of interest. Prior to Fourier transformation the image section is multiplied with a window, which gradually falls off to zero at the edges. The user indicates interactively the periodicities of interest by selecting spots in the digital diffractogram. A fine search for each selected frequency is implemented using a bilinear interpolation, which is dependent on the window function. It is possible to refine the estimation even further using a non-linear least squares estimation. The first two steps provide the proper starting values for the numerical minimization (e.g. Gauss-Newton). This third step increases the precision with 30% to the highest theoretically attainable (Cramer and Rao Lower Bound). In the present studies we use a Gatan 622 TV camera attached to the JEM 4000EX electron microscope. Image analysis is implemented on a Micro VAX II computer equipped with a powerful array processor and real time image processing hardware. The typical precision, as defined by the standard deviation of the distribution of measurement errors, is found to be <0.003Å measured on single crystal silicon and <0.02Å measured on small (10-30Å) specimen areas. These values are ×10 times larger than predicted by theory. Furthermore, the measured precision is observed to be independent on signal-to-noise ratio (determined by the number of averaged TV frames). Obviously, the precision is restricted by geometric distortion mainly caused by the TV camera. For this reason, we are replacing the Gatan 622 TV camera with a modern high-grade CCD-based camera system. Such a system not only has negligible geometric distortion, but also high dynamic range (>10,000) and high resolution (1024x1024 pixels). The geometric distortion of the projector lenses can be measured, and corrected through re-sampling of the digitized image.

Performance Characteristics of Methods for the Bacteriological Examination of Water

1993 ◽  
Vol 27 (3-4) ◽  
pp. 1-13 ◽  
Author(s):  
Arie H. Havelaar ◽  
Siem H. Heisterkamp ◽  
Janneke A. Hoekstra ◽  
Kirsten A. Mooijman
Keyword(s):  
Sensitivity And Specificity ◽  
Measurement Errors ◽  
Systematic Errors ◽  
General Concept ◽  
Growth Characteristics ◽  
Performance Characteristics ◽  
Logarithmic Scale ◽  
Bacteriological Examination ◽  
Membrane Filters

The general concept of measurement errors is applied to quantitative bacteriological counts on membrane filters or agar plates. The systematic errors of these methods are related to the growth characteristics of the medium (recovery of target organisms and inhibition of non-target organisms) and to its differential characteristics (sensitivity and specificity). Factors that influence the precision of microbiological counts are the variation between replicates, within samples, between operators and between laboratories. It is also affected by the linearity of the method, the verification rate and, where applicable, the number of colonies subcultured for verification. Repeatability (r) and reproducibility (R) values can be calculated on the logarithmic scale.

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