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We conduct an analysis of over 60,000 dwarf galaxies (7<=log(M_*/M_\odot)<=10) in search of photometric variability indicative of active galactic nuclei (AGNs). Using data from the Young Supernova Experiment (YSE), a time domain survey on…

We present the first results of an ongoing variability monitoring program of active galactic nuclei (AGNs) using the 46\,cm telescope of the Wise observatory in Israel. The telescope has a field of view of $1.25^{\circ} \times 0.84^{\circ}$…

Astrophysics of Galaxies · Physics 2017-07-26 F. Pozo Nuñez , D. Chelouche , S. Kaspi , S. Niv

We report on two distinct computational approaches to self-consistently measure photospheric properties of large samples of stars. Both procedures consist of a set of several semi-integrated tasks based on shell and Python scripts, which…

Solar and Stellar Astrophysics · Physics 2013-09-04 Andre Milone , Ronaldo da Silva , Anne Sansom , Patricia Sanchez-Blazquez

A novel static algorithm is proposed for numerical reparametrization of periodic planar curves. The method identifies a monitor function of the arclength variable with the true curvature of an open planar curve and considers a simple…

Numerical Analysis · Mathematics 2022-03-21 Kazuki Koga

We apply a combination of a Genetic Algorithms (GA) and Support Vector Machines (SVM) machine learning algorithm to solve two important problems faced by the astronomical community: star/galaxy separation, and photometric redshift…

Instrumentation and Methods for Astrophysics · Physics 2016-04-27 S. Heinis , S. Kumar , S. Gezari , W. S. Burgett , K. C. Chambers , P. W. Draper , H. Flewelling , N. Kaiser , E. A. Magnier , N. Metcalfe , C. Waters

ATLAS (Asteroid Terrestrial Last Alert System) is a time-domain survey using four telescopes, covering the entire sky. It has observed over 10,000 spectroscopically confirmed Type Ia supernovae (SNe~Ia), with thousands of cosmology-grade…

Wavelength calibration is a routine and critical part of any spectral work-flow, but many astronomers still resort to matching detected peaks and emission lines by hand. We present RASCAL (RANSAC Assisted Spectral CALibration), a python…

Instrumentation and Methods for Astrophysics · Physics 2019-12-13 Josh Veitch-Michaelis , Marco C Lam

Reverberation mapping (RM) is an important technique in studies of active galactic nuclei (AGN). The key idea of RM is to measure the time lag $\tau$ between variations in the continuum emission from the accretion disc and subsequent…

Instrumentation and Methods for Astrophysics · Physics 2015-06-18 Brendon J. Brewer , Tom M. Elliott

The Vera C. Rubin Observatory's Legacy Survey of Space and Time (LSST) will monitor tens of millions of active galactic nuclei (AGNs) for a period of 10 years with an average cadence of 3 days in six broad photometric bands. This…

A key processing step in ground-based astronomy involves combining multiple noisy and blurry exposures to produce an image of the night sky with an improved signal-to-noise ratio. Typically, this is achieved via image coaddition, and can be…

Instrumentation and Methods for Astrophysics · Physics 2025-09-15 Yashil Sukurdeep , Tamás Budavári , Andrew J. Connolly , Fausto Navarro

We investigate a new scheme for astronomical spectrograph calibration using the laser frequency comb at the Solar Vacuum Tower Telescope on Tenerife. Our concept is based upon a single-mode fiber channel, that simultaneously feeds the…

Instrumentation and Methods for Astrophysics · Physics 2015-02-18 R A Probst , L Wang , H-P Doerr , T Steinmetz , T J Kentischer , G Zhao , T W Hänsch , Th Udem , R Holzwarth , W Schmidt

Radio-astronomical observations are increasingly contaminated by interference, and suppression techniques become essential. A powerful candidate for interference mitigation is adaptive spatial filtering. We study the effect of spatial…

Astrophysics · Physics 2014-10-13 Amir Leshem , Alle-Jan van der Veen

Most time-series models assume that the data come from observations that are equally spaced in time. However, this assumption does not hold in many diverse scientific fields, such as astronomy, finance, and climatology, among others. There…

Instrumentation and Methods for Astrophysics · Physics 2019-07-17 Felipe Elorrieta , Susana Eyheramendy , Wilfredo Palma

Many approaches to astronomical data reduction and analysis cannot tolerate missing data: corrupted pixels must first have their values imputed. This paper presents astrofix, a robust and flexible image imputation algorithm based on…

Instrumentation and Methods for Astrophysics · Physics 2021-09-17 Hengyue Zhang , Timothy D. Brandt

With the availability of large-scale surveys like Kepler and TESS, there is a pressing need for automated methods to classify light curves according to known classes of variable stars. We introduce a new algorithm for classifying light…

Solar and Stellar Astrophysics · Physics 2022-06-30 Nicholas H. Barbara , Timothy R. Bedding , Ben D. Fulcher , Simon J. Murphy , Timothy Van Reeth

Having a need to perform differential photometry for tens of thousands stars in a several square degrees field, we developed Astrokit program. The software corrects the star brightness variations caused by variations of atmospheric…

Instrumentation and Methods for Astrophysics · Physics 2015-06-22 Artem Y. Burdanov , Vadim V. Krushinsky , Alexander A. Popov

Starlight corrupted by atmospheric turbulence cannot couple efficiently into astronomical instruments based on integrated optics as they require light of high spatial coherence to couple into their single-mode waveguides. Low-order adaptive…

Instrumentation and Methods for Astrophysics · Physics 2021-03-26 Momen Diab , Aline N. Dinkelaker , John Davenport , Kalaga Madhav , Martin M. Roth

In direct imaging at high contrast, the bright glare produced by the host star makes the detection and the characterization of sub-stellar companions particularly challenging. In spite of the use of an extreme adaptive optics system…

Instrumentation and Methods for Astrophysics · Physics 2024-09-23 Olivier Flasseur , Théo Bodrito , Julien Mairal , Jean Ponce , Maud Langlois , Anne-Marie Lagrange

Rigid registration of multi-view and multi-platform LiDAR scans is a fundamental problem in 3D mapping, robotic navigation, and large-scale urban modeling applications. Data acquisition with LiDAR sensors involves scanning multiple areas…

Computer Vision and Pattern Recognition · Computer Science 2020-02-03 Aby Thomas , Adarsh Sunilkumar , Shankar Shylesh , Aby Abahai T. , Subhasree Methirumangalath , Dong Chen , Jiju Peethambaran

A novel method nicknamed ELASTIC is proposed for the alignment of multiple-aperture telescopes, in particular segmented telescopes. It only needs the acquisition of two diversity images of an unresolved source, and is based on the…

Instrumentation and Methods for Astrophysics · Physics 2017-08-02 S. Vievard , F. Cassaing , L. M. Mugnier