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We investigate the performance of the scan (maximum likelihood ratio statistic) and of the average likelihood ratio statistic in the problem of detecting a deterministic signal with unknown spatial extent in the prototypical univariate…

Methodology · Statistics 2014-02-26 Hock Peng Chan , Guenther Walther

The characterization and reconstruction of heterogeneous materials, such as porous media and electrode materials, involve the application of image processing methods to data acquired by microscopy techniques. In this study, we present a…

Image and Video Processing · Electrical Eng. & Systems 2018-02-21 Rene Ledesma-Alonso , Romeli Barbosa , Jaime Ortegon

Follow-up observations at high-angular resolution of submillimeter galaxies showed that the single-dish sources are comprised of a blend of several galaxies. Consequently, number counts derived from low and high angular resolution…

We present an investigation into the effects of survey systematics such as varying depth, point spread function (PSF) size, and extinction on the galaxy selection and correlation in photometric, multi-epoch, wide area surveys. We take the…

Cosmology and Nongalactic Astrophysics · Physics 2015-09-16 Christopher Brian Morrison , Hendrik Hildebrandt

The study of the magnification bias produced on high-redshift sub-millimetre galaxies by foreground galaxies through the analysis of the cross-correlation function was recently demonstrated as an interesting independent alternative to the…

Cosmology and Nongalactic Astrophysics · Physics 2021-02-24 J. Gonzalez-Nuevo , M. M. Cueli , L. Bonavera , A. Lapi , M. Migliaccio , F. Argüeso , L. Toffolatti

We investigate the stability of a segmented deformable mirror (DM) on high-contrast testbeds and its impact on the images produced with coronagraphs. Segmented apertures are promising to obtain large primary mirrors for future missions with…

Despite its empirical success, the theoretical foundations of self-supervised contrastive learning (CL) are not yet fully established. In this work, we address this gap by showing that standard CL objectives implicitly approximate a…

Machine Learning · Computer Science 2025-11-12 Achleshwar Luthra , Tianbao Yang , Tomer Galanti

Direct exo-Earth imaging is a key science goal for astronomy in the next decade. This ambitious task imposes a target contrast of ~10^-7 at wavelengths from I to J-band. In our prior study, we determined that polarization aberrations can…

Imaging terrestrial exoplanets around nearby stars is a formidable technical challenge, requiring the development of coronagraphs to suppress the stellar halo of diffracted light at the location of the planet. In this review, we derive the…

Instrumentation and Methods for Astrophysics · Physics 2025-06-04 Matthew A. Kenworthy , Sebastiaan Y. Haffert

Direct imaging of exoplanets is a challenging task as it requires to reach a high contrast at very close separation to the star. Today, the main limitation in the high-contrast images is the quasi-static speckles that are created by…

Instrumentation and Methods for Astrophysics · Physics 2019-05-22 Benoît Pairet , Faustine Cantalloube , Carlos A. Gomez Gonzalez , Olivier Absil , Laurent Jacques

Weak lensing surveys are expected to provide direct measurements of the statistics of the projected dark matter distribution. Most analytical studies of weak lensing statistics have been limited to quasilinear scales as they relied on…

Astrophysics · Physics 2009-10-31 Dipak Munshi , Bhuvnesh Jain

Cluster-scale strong lensing is a powerful tool for exploring the properties of dark matter and constraining cosmological models. However, due to the complex parameter space, pixelized strong lens modeling in galaxy clusters is…

Cosmology and Nongalactic Astrophysics · Physics 2024-05-07 Yushan Xie , Huanyuan Shan , Nan Li , Ran Li , Eric Jullo , Chen Su , Xiaoyue Cao , Jean-Paul Kneib , Ana Acebron , Mengfan He , Ji Yao , Chunxiang Wang , Jiadong Li , Yin Li

Ptychography provides high dose efficiency images that can reveal light elements next to heavy atoms. However, despite ptychography having an otherwise single signed contrast transfer function, contrast reversals can occur when the…

Applied Physics · Physics 2023-06-16 C. Gao , C. Hofer , T. J. Pennycook

Context: The number of known strong gravitational lenses is expected to grow substantially in the next few years. The statistical combination of large samples of lenses has the potential of providing strong constraints on the inner…

Astrophysics of Galaxies · Physics 2021-07-07 Alessandro Sonnenfeld , Marius Cautun

We have studied the effect of limited statistics of data on measurement of the different order of cumulants of net-proton distribution assuming that the proton and antiproton distributions follow Possionian and Binomial distributions with…

Nuclear Experiment · Physics 2019-10-02 Ashish Pandav , Debasish Mallick , Bedangadas Mohanty

In the recent years, we witness a great interest in imaging, in a wide sense, using contrast agents. One of the reasons is that many imaging modalities, as the ones related to medical sciences, suffer from several shortcomings. The most…

Optics · Physics 2020-08-28 Ahcene Ghandriche , Mourad Sini

Direct imaging of exoplanets requires very high contrast levels, which are obtained using coronagraphs. But residual quasi-static aberrations create speckles in the focal plane downstream of the coronagraph which mask the planet. This…

Instrumentation and Methods for Astrophysics · Physics 2015-06-16 J. Mazoyer , P. Baudoz , R. Galicher , M. Mas , G. Rousset

We present the small-scale (0.2h^{-1} to 7h^{-1} Mpc) cross-correlations between 32,000 luminous early-type galaxies and a reference sample of 16 million normal galaxies from the Sloan Digital Sky Survey. Our method allows us to construct…

We investigate whether a Gaussian likelihood, as routinely assumed in the analysis of cosmological data, is supported by simulated survey data. We define test statistics, based on a novel method that first destroys Gaussian correlations in…

Cosmology and Nongalactic Astrophysics · Physics 2017-11-15 Elena Sellentin , Alan F. Heavens

The stellar initial mass function (IMF) high-mass slope $\alpha$ is routinely measured by fitting single-star models to photometric samples that contain 20-90% unresolved binaries. This practice introduces a systematic negative bias on…

Solar and Stellar Astrophysics · Physics 2026-03-18 Anna L. Rosen