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Straightforward methods for adapting the familiar chi^2 statistic to histograms of discrete events and other Poisson distributed data generally yield biased estimates of the parameters of a model. The bias can be important even when the…

Data Analysis, Statistics and Probability · Physics 2014-03-12 Joseph W. Fowler

We present the results from combining machine learning with the profile likelihood fit procedure, using data from the Large Underground Xenon (LUX) dark matter experiment. This approach demonstrates reduction in computation time by a factor…

Gravitational lensing shear has the potential to be the most powerful tool for constraining the nature of dark energy. However, accurate measurement of galaxy shear is crucial and has been shown to be non-trivial by the Shear TEsting…

Cosmology and Nongalactic Astrophysics · Physics 2015-05-13 L. M. Voigt , S. L. Bridle

We propose a complete framework for the detection, astrometry, and photometry of faint companions from a sequence of adaptive optics corrected short exposures. The algorithms exploit the difference in statistics between the on-axis and…

Astrophysics · Physics 2011-02-11 Szymon Gladysz , Julian C. Christou

Semi-empirical models of the solar Chromosphere show in their emission spectrum, tomography property at millimeter, sub-millimeter, and infrared wavelengths for the center of the solar disk. In this work, we studied this property in the…

Solar and Stellar Astrophysics · Physics 2017-03-22 Victor De la Luz , J. A. Gonzalez-Esparza , P. Corona-Romero , J. Mejia-Ambriz

The assumption that a parametric class of functions fits the data structure sufficiently well is common in fitting curves and surfaces to regression data. One then derives a parameter estimate resulting from a least squares fit, say, and in…

Astrophysics · Physics 2009-11-06 Nicolai Bissantz , Axel Munk

Spectral retrieval techniques are currently our best tool to interpret the observed exoplanet atmospheric data. Said techniques retrieve the optimal atmospheric components and parameters by identifying the best fit to an observed…

Earth and Planetary Astrophysics · Physics 2020-10-21 Kai Hou Yip , Ingo P. Waldmann , Angelos Tsiaras , Giovanna Tinetti

We measured the center-to-limb variation of the brightness temperature, $T_b$, from ALMA full-disk images at two frequencies and inverted the solution of the transfer equation to obtain the electron temperature, $T_e$ as a function of…

Solar and Stellar Astrophysics · Physics 2017-09-13 C. E. Alissandrakis , S. Patsourakos , A. Nindos , T. S. Bastian

Data from transit light curves, radial velocity and transit timing observations can be used to probe the interiors of exoplanets beyond the mean density, by measuring the Love numbers $h_2$ and $k_2$. The first indirect estimate of $k_2$…

Earth and Planetary Astrophysics · Physics 2020-01-28 Hugo Hellard , Szilárd Csizmadia , Sebastiano Padovan , Frank Sohl , Heike Rauer

Kjeldsen et al. (1995, AJ 109, 1313; astro-ph/9411016) have developed a new technique for measuring stellar oscillations and claimed a detection in the G subgiant eta Boo. The technique involves monitoring temperature fluctuations in a star…

Astrophysics · Physics 2015-06-24 T. R. Bedding , H. Kjeldsen , J. Reetz , B. Barbuy

Broad-band images in the Ca II H line, from the BFI instrument on the Hinode spacecraft, show emission from spicules emerging from and visible right down to the observed limb. Surprisingly, little absorption of spicule light is seen along…

Solar and Stellar Astrophysics · Physics 2015-05-18 Philip G. Judge , Mats Carlsson

Modelling gravity is a fundamental problem that must be tackled in N-body simulations of stellar systems, and satisfactory solutions require a deep understanding of the dynamical effects of softening. In a previous paper (Romeo 1997), we…

Astrophysics · Physics 2007-05-23 Alessandro B. Romeo

Metacalibration is a state-of-the-art technique for measuring weak gravitational lensing shear from well-sampled galaxy images. We investigate the accuracy of shear measured with metacalibration from fitting elliptical Gaussians to…

Instrumentation and Methods for Astrophysics · Physics 2021-03-03 Arun Kannawadi , Erik Rosenberg , Henk Hoekstra

Future experiments will produce high-resolution temperature maps of the cosmic microwave background (CMB) and are expected to reveal the signature of gravitational lensing by intervening large-scale structures. We construct all-sky…

Astrophysics · Physics 2009-11-07 Christopher M. Hirata , Uros Seljak

We present current and future constraints on equations of state for dark sector perturbations. The equations of state considered are those corresponding to a generalized scalar field model and time-diffeomorphism invariant $L(g)$ theories…

Cosmology and Nongalactic Astrophysics · Physics 2015-06-29 Richard A. Battye , Adam Moss , Jonathan A. Pearson

Transmission spectroscopy provides us with information on the atmospheric properties at the limb, which is often intuitively assumed to be a narrow annulus around the planet. Consequently, studies have focused on the effect of atmospheric…

Earth and Planetary Astrophysics · Physics 2019-03-27 Anthony Caldas , Jérémy Leconte , Franck Selsis , Ingo Waldmann , Pascal Bordé , Marco Rocchetto , Benjamin Charnay

We present direct measurements of the limb-darkened intensity profiles of the late-type giant stars HR5299, HR7635, and HR8621 obtained with the Navy Prototype Optical Interferometer (NPOI) at the Lowell Observatory. A triangle of baselines…

Astrophysics · Physics 2009-11-07 M. Wittkowski , C. A. Hummel , K. J. Johnston , D. Mozurkewich , A. R. Hajian , N. M. White

The quiet solar coronal heating problem and the observed center-to-limb wavelength variations of the solar lines (limb effect) can be explained. In this paper the quantitative calculations for these two phenomena are presented.

General Physics · Physics 2013-10-02 Yi-Jia Zheng

Context. Scattering and absorption processes in stellar atmosphere affect the center-to-limb variations of the intensity (CLVI) and the linear polarization (CLVP) of stellar radiation. Aims. There are several theoretical and observational…

Solar and Stellar Astrophysics · Physics 2015-03-04 N. M. Kostogryz , S. V. Berdyugina

As recently shown by Viola et al., the common (KSB) method for measuring weak gravitational shear creates a non-linear relation between the measured and the true shear of objects. We investigate here what effect such a non-linear…

Cosmology and Nongalactic Astrophysics · Physics 2015-05-27 Matthias Bartelmann , Massimo Viola , Peter Melchior , Björn M. Schäfer