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Verification of commercial motor performance for WEAVE at the William Herschel Telescope: WEAVE is a 1000-fiber multi-object spectroscopic facility for the 4.2~m William Herschel Telescope. It will feature a double-headed pick-and-place fiber positioning robot comprising commercially available robotic axes. This pape...
astro-ph_IM
Low-order wavefront control using a Zernike sensor through Lyot coronagraphs for exoplanet imaging: Combining large segmented space telescopes, coronagraphy and wavefront control methods is a promising solution to produce a dark hole (DH) region in the coronagraphic image of an observed star and study planetary compa...
astro-ph_IM
AstroDS -- A Distributed Storage for Astrophysics of Cosmic Rays. Current Status: Currently, the processing of scientific data in astroparticle physics is based on various distributed technologies, the most common of which are Grid and cloud computing. The most frequently discussed approaches are focused on large and...
astro-ph_IM
How to write and develop your astronomy research paper: Writing is a vital component of a modern career in scientific research. But how to write correctly and effectively is often not included in the training that young astronomers receive from their supervisors and departments. We offer a step-by-step guide to tackle ...
astro-ph_IM
Focus diverse phase retrieval testbed development of continuous wavefront sensing for space telescope applications: Continuous wavefront sensing on future space telescopes allows relaxation of stability requirements while still allowing on-orbit diffraction-limited optical performance. We consider the suitability of ...
astro-ph_IM
An improved method for polarimetric image restoration in interferometry: Interferometric radio astronomy data require the effects of limited coverage in the Fourier plane to be accounted for via a deconvolution process. For the last 40 years this process, known as `cleaning', has been performed almost exclusively on al...
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UVscope and its application aboard the ASTRI-Horn telescope: UVscope is an instrument, based on a multi-pixel photon detector, developed to support experimental activities for high-energy astrophysics and cosmic ray research. The instrument, working in single photon counting mode, is designed to directly measure light ...
astro-ph_IM
CHIME FRB: An application of FFT beamforming for a radio telescope: We have developed FFT beamforming techniques for the CHIME radio telescope, to search for and localize the astrophysical signals from Fast Radio Bursts (FRBs) over a large instantaneous field-of-view (FOV) while maintaining the full angular resolution ...
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A key-formula to compute the gravitational potential of inhomogeneous discs in cylindrical coordinates: We have established the exact expression for the gravitational potential of a homogeneous polar cell - an elementary pattern used in hydrodynamical simulations of gravitating discs. This formula, which is a closed-...
astro-ph_IM
Design and Performance of the GAMMA-400 Gamma-Ray Telescope for the Dark Matter Searches: The GAMMA-400 gamma-ray telescope is designed to measure the fluxes of gamma rays and cosmic-ray electrons + positrons, which can be produced by annihilation or decay of the dark matter particles, as well as to survey the celest...
astro-ph_IM
Theory and Simulations of Refractive Substructure in Resolved Scatter-Broadened Images: At radio wavelengths, scattering in the interstellar medium distorts the appearance of astronomical sources. Averaged over a scattering ensemble, the result is a blurred image of the source. However, Narayan & Goodman (1989) and G...
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SciCodes: Astronomy Research Software and Beyond: The Astrophysics Source Code Library (ASCL ascl.net), started in 1999, is a free open registry of software used in refereed astronomy research. Over the past few years, it has spearheaded an effort to form a consortium of scientific software registries and repositories....
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Interstellar Now! Missions to and Sample Returns from Nearby Interstellar Objects: The recently discovered first high velocity hyperbolic objects passing through the Solar System, 1I/'Oumuamua and 2I/Borisov, have raised the question about near term missions to Interstellar Objects. In situ spacecraft exploration of ...
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Impact of particles on the Planck HFI detectors: Ground-based measurements and physical interpretation: The Planck High Frequency Instrument (HFI) surveyed the sky continuously from August 2009 to January 2012. Its noise and sensitivity performance were excellent, but the rate of cosmic ray impacts on the HFI detecto...
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Sparsity and the Bayesian Perspective: Sparsity has been recently introduced in cosmology for weak-lensing and CMB data analysis for different applications such as denoising, component separation or inpainting (i.e. filling the missing data or the mask). Although it gives very nice numerical results, CMB sparse inpaint...
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Frequency chirped continuous-wave sodium laser guide stars: We numerically study a method to increase the photon return flux of continuous-wave laser guide stars using one-dimensional atomic cooling principles. The method relies on chirping the laser towards higher frequencies following the change in velocity of sodium...
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DiskFM: A Forward Modeling Tool for Disk Analysis with Coronagraphic Instruments: Because of bright starlight leakage in coronagraphic raw images, faint astrophysical objects such as exoplanets can only be detected using powerful point spread function (PSF) subtraction algorithms. However, these algorithms have stron...
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A Lightweight Space-based Solar Power Generation and Transmission Satellite: We propose a novel design for a lightweight, high-performance space-based solar power array combined with power beaming capability for operation in geosynchronous orbit and transmission of power to Earth. We use a modular configuration of sm...
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DISCO: a Spatio-Spectral Recombiner for Pupil Remapping Interferometry: Pupil-remapping is a new high-dynamic range imaging technique that has recently demonstrated feasibility on sky. The current prototypes present however deceiving limiting magnitude, restricting the current use to the brightest stars in the sky. We ...
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Machine learning applications in astrophysics: Photometric redshift estimation: Machine learning has rose to become an important research tool in the past decade, its application has been expanded to almost if not all disciplines known to mankind. Particularly, the use of machine learning in astrophysics research had...
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Systematic biases in low frequency radio interferometric data due to calibration: the LOFAR EoR case: The redshifted 21 cm line of neutral hydrogen is a promising probe of the Epoch of Reionization (EoR). However, its detection requires a thorough understanding and control of the systematic errors. We study two syste...
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Performance analysis of the Least-Squares estimator in Astrometry: We characterize the performance of the widely-used least-squares estimator in astrometry in terms of a comparison with the Cramer-Rao lower variance bound. In this inference context the performance of the least-squares estimator does not offer a closed-...
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Science with the Murchison Widefield Array: Significant new opportunities for astrophysics and cosmology have been identified at low radio frequencies. The Murchison Widefield Array is the first telescope in the Southern Hemisphere designed specifically to explore the low-frequency astronomical sky between 80 and 300 M...
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GRID: a Student Project to Monitor the Transient Gamma-Ray Sky in the Multi-Messenger Astronomy Era: The Gamma-Ray Integrated Detectors (GRID) is a space mission concept dedicated to monitoring the transient gamma-ray sky in the energy range from 10 keV to 2 MeV using scintillation detectors onboard CubeSats in low E...
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LSST is Not "Big Data": LSST promises to be the largest optical imaging survey of the sky. If we were fortunate enough to have the equivalent of LSST today, it would represent a "fire hose" of data that would be difficult to store, transfer, and analyze with available compute resources. LSST parallels the SDSS comput...
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galmask: A Python package for unsupervised galaxy masking: Galaxy morphological classification is a fundamental aspect of galaxy formation and evolution studies. Various machine learning tools have been developed for automated pipeline analysis of large-scale surveys, enabling a fast search for objects of interest. How...
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The next generation Cherenkov Telescope Array observatory: CTA: The Cherenkov Telescope Array (CTA) is a large collaborative effort aimed at the design and operation of an observatory dedicated to the VHE gamma-ray astrophysics in the energy range 30 GeV-100 TeV, which will improve by about one order of magnitude the s...
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The CALSPEC Stars P177D and P330E: Multicolor photometric data are presented for the CALSPEC stars P177D and P330E. Together with previously published photometry for nine other CALSPEC standards, the photometric observations and synthetic photometry from HST/STIS spectrophotometry agree in the B, V, R, and I bands to b...
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Subsystem Development for the All-Sky Medium Energy Gamma-ray Observatory (AMEGO) prototype: The gamma-ray sky from several hundred keV to $\sim$ a hundred MeV has remained largely unexplored due to the challenging nature of detecting gamma rays in this regime. At lower energies, Compton scattering is the dominant in...
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Software solutions for numerical modeling of wide-field telescopes: This paper presents an integrated modeling software to analyze the PSF of wide-field telescopes affected by misalignments. Even relatively small misalignments in the optical system of a telescope can significantly deteriorate the image quality by intro...
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Improved Acceleration of the GPU Fourier Domain Acceleration Search Algorithm: We present an improvement of our implementation of the Correlation Technique for the Fourier Domain Acceleration Search (FDAS) algorithm on Graphics Processor Units (GPUs) (Dimoudi & Armour 2015; Dimoudi et al. 2017). Our new improved conv...
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Visualising three-dimensional volumetric data with an arbitrary coordinate system: Astronomical data does not always use Cartesian coordinates. Both all-sky observational data and simulations of rotationally symmetric systems, such as accretion and protoplanetary discs, may use spherical polar or other coordinate sys...
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Concept validation of a high dynamic range point-diffraction interferometer for wavefront sensing in adaptive optics: The direct detection and imaging of exoplanets requires the use of high-contrast adaptive optics (AO). In these systems quasi-static aberrations need to be highly corrected and calibrated. In order to...
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A Small Satellite Version of a Broad-band Soft X-ray Polarimeter: We describe a new implementation of a broad-band soft X-ray polarimeter, substantially based on a previous design. This implementation, the Pioneer Soft X-ray Polarimeter (PiSoX) is a SmallSat, designed for NASA's call for Astrophysics Pioneers, small mi...
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Variable Star Classification Using Multi-View Metric Learning: Our multi-view metric learning framework enables robust characterization of star categories by directly learning to discriminate in a multi-faceted feature space, thus, eliminating the need to combine feature representations prior to fitting the machine lea...
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Combined Opto-Acoustical Sensor Modules for KM3NeT: KM3NeT is a future multi-cubic-kilometre water Cherenkov neutrino telescope currently entering a first construction phase. It will be located in the Mediterranean Sea and comprise about 600 vertical structures called detection units. Each of these detection units has ...
astro-ph_IM
Accelerating Multiframe Blind Deconvolution via Deep Learning: Ground-based solar image restoration is a computationally expensive procedure that involves nonlinear optimization techniques. The presence of atmospheric turbulence produces perturbations in individual images that make it necessary to apply blind deconvolu...
astro-ph_IM
AI and extreme scale computing to learn and infer the physics of higher order gravitational wave modes of quasi-circular, spinning, non-precessing binary black hole mergers: We use artificial intelligence (AI) to learn and infer the physics of higher order gravitational wave modes of quasi-circular, spinning, non p...
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Stellar populations in the ELT perspective: We discuss the impact that the next generation of Extremely Large Telescopes will have on the open astrophysical problems of resolved stellar populations. In particular, we address the interplay between multiband photometry and spectroscopy.
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Detectability of Galactic Faraday Rotation in Multi-wavelength CMB Observations: A Cross-Correlation Analysis of CMB and Radio Maps: We introduce a new cross-correlation method to detect and verify the astrophysical origin of Faraday Rotation (FR) in multiwavelength surveys. FR is well studied in radio astronomy from...
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Using weighting algorithms to refine source direction determinations in all-sky gravitational wave burst searches with two-detector networks: I explore the possibility of resurrecting an old, non-Bayesian computational approach for inferring the source direction of a gravitational wave from the output of a two-detect...
astro-ph_IM
Correcting for the ionosphere in the uv-plane: In radio astronomy, the correlator measures intensity in visibility space. In addition, the EoR power spectrum measured by an experiment such as the MWA is constructed in visibility space. Thus, correcting for the ionosphere in the uv-plane instead of real space could pote...
astro-ph_IM
Sparse aperture masking at the VLT I. Faint companion detection limits for the two debris disk stars HD 92945 and HD 141569: Observational data on companion statistics around young stellar systems is needed to flesh out the formation pathways for extrasolar planets and brown dwarfs. Aperture masking is a new techniqu...
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Millimeter/submillimeter VLBI with a Next Generation Large Radio Telescope in the Atacama Desert: The proposed next generation Event Horizon Telescope (ngEHT) concept envisions the imaging of various astronomical sources on scales of microarcseconds in unprecedented detail with at least two orders of magnitude improv...
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The KAGRA underground environment and lessons for the Einstein Telescope: The KAGRA gravitational-wave detector in Japan is the only operating detector hosted in an underground infrastructure. Underground sites promise a greatly reduced contribution of the environment to detector noise thereby opening the possibility t...
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Real-time Data Ingestion at the Keck Observatory Archive (KOA): Since February of this year, KOA began to prepare, transfer, and ingest data as they were acquired in near-real time; in most cases data are available to observers through KOA within one minute of acquisition. Real-time ingestion will be complete for all a...
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Inferring the properties of a population of compact binaries in presence of selection effects: Shortly after a new class of objects is discovered, the attention shifts from the properties of the individual sources to the question of their origin: do all sources come from the same underlying population, or several pop...
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Design of the KOSMOS oil-coupled spectrograph camera lenses: We present the design details of oil-coupled lens groups used in the KOSMOS spectrograph camera. The oil-coupled groups use silicone rubber O-rings in a unique way to accurately center lens elements with high radial and axial stiffness while also allowing eas...
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Introducing Astronomy into Mozambican Society: Mozambique has been proposed as a host for one of the future Square Kilometre Array stations in Southern Africa. However, Mozambique does not possess a university astronomy department and only recently has there been interest in developing one. South Africa has been fundin...
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Electrode level Monte Carlo model of radiation damage effects on astronomical CCDs: Current optical space telescopes rely upon silicon Charge Coupled Devices (CCDs) to detect and image the incoming photons. The performance of a CCD detector depends on its ability to transfer electrons through the silicon efficiently,...
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Giant Radio Array for Neutrino Detection (GRAND): GRAND is a newly proposed series of radio arrays with a combined area of 200,000 square km, to be deployed in mountainous areas. Its primary goal is to measure cosmic ultra-high-energy tau-neutrinos (E>1 EeV), through the interaction of these neutrinos in rock and the d...
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New SST Optical Sensor of Pampilhosa da Serra: studies on image processing algorithms and multi-filter characterization of Space Debris: As part of the Portuguese Space Surveillance and Tracking (SST) System, two new Wide Field of View (2.3deg x 2.3deg) small aperture (30cm) telescopes will be deployed in 2021, at th...
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The Solar Probe ANalyzers -- Electrons on Parker Solar Probe: Electrostatic analyzers of different designs have been used since the earliest days of the space age, beginning with the very earliest solar wind measurements made by Mariner 2 en route to Venus in 1962. The Parker Solar Probe (PSP) mission, NASA's first ded...
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Optical Design and Characterization of 40-GHz Detector and Module for the BICEP Array: Families of cosmic inflation models predict a primordial gravitational-wave background that imprints B-mode polarization pattern in the Cosmic Microwave Background (CMB). High sensitivity instruments with wide frequency coverage an...
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Physically constrained causal noise models for high-contrast imaging of exoplanets: The detection of exoplanets in high-contrast imaging (HCI) data hinges on post-processing methods to remove spurious light from the host star. So far, existing methods for this task hardly utilize any of the available domain knowledge...
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Automated Real-Time Classification and Decision Making in Massive Data Streams from Synoptic Sky Surveys: The nature of scientific and technological data collection is evolving rapidly: data volumes and rates grow exponentially, with increasing complexity and information content, and there has been a transition from ...
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Long term measurements from the Mátra Gravitational and Geophysical Laboratory: Summary of the long term data taking, related to one of the proposed next generation ground-based gravitational detector's location is presented here. Results of seismic and infrasound noise, electromagnetic attenuation and cosmic muon ra...
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Imfit: A Fast, Flexible New Program for Astronomical Image Fitting: I describe a new, open-source astronomical image-fitting program called Imfit, specialized for galaxies but potentially useful for other sources, which is fast, flexible, and highly extensible. A key characteristic of the program is an object-oriented ...
astro-ph_IM
Experimental study on Modified Linear Quadratic Gaussian Control for Adaptive Optics: To achieve high resolution imaging the standard control algorithm used for classical adaptive optics (AO) is the simple but efficient proportional-integral (PI) controller. The goal is to minimize the root mean square (RMS) error of...
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Simulations of astrometric planet detection in Alpha Centauri by intensity interferometry: Recent dynamical studies indicate that the possibility of an Earth-like planet around $\alpha\;$Cen A or B should be taken seriously. Such a planet, if it exists, would perturb the orbital astrometry by $<10 \ {\mu}\rm as$, whi...
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The Habitable Zone Planet Finder: A Proposed High Resolution NIR Spectrograph for the Hobby Eberly Telescope to Discover Low Mass Exoplanets around M Dwarfs: The Habitable Zone Planet Finder (HZPF) is a proposed instrument for the 10m class Hobby Eberly telescope that will be capable of discovering low mass planets...
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High contrast imaging at the photon noise limit with self-calibrating WFS/C systems: High contrast imaging (HCI) systems rely on active wavefront control (WFC) to deliver deep raw contrast in the focal plane, and on calibration techniques to further enhance contrast by identifying planet light within the residual spe...
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Interferometric Beam Combination with a Triangular Tricoupler Photonic Chip: Beam combiners are important components of an optical/infrared astrophysical interferometer, with many variants as to how to optimally combine two or more beams of light to fringe-track and obtain the complex fringe visibility. One such meth...
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Archival Legacy Investigations of Circumstellar Environments (ALICE): Statistical assessment of point source detections: The ALICE program, for Archival Legacy Investigation of Circumstellar Environment, is currently conducting a virtual survey of about 400 stars, by re-analyzing the HST-NICMOS coronagraphic archive ...
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A Condition Monitoring Concept Studied at the MST Prototype for the Cherenkov Telescope Array: The Cherenkov Telescope Array (CTA) is a future ground-based gamma-ray observatory that will provide unprecedented sensitivity and angular resolution for the detection of gamma rays with energies above a few tens of GeV. In...
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KLLR: A scale-dependent, multivariate model class for regression analysis: The underlying physics of astronomical systems governs the relation between their measurable properties. Consequently, quantifying the statistical relationships between system-level observable properties of a population offers insights into th...
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The Venus ground-based image Active Archive: a database of amateur observations of Venus in ultraviolet and infrared light: The Venus ground-based image Active Archive is an online database designed to collect ground-based images of Venus in such a way that they are optimally useful for science. The Archive was built...
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Optimal Dithering Configuration Mitigating Rayleigh-Backscattering-Induced Distortion in Radioastronomic Optical Fiber Systems: In the context of Radioastronomic applications where the Analog Radio-over-Fiber technology is used for the antenna downlink, detrimental nonlinearity effects arise because of the interfer...
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H2 distribution during 2-phase Molecular Cloud Formation: We performed high-resolution, 3D MHD simulations and we compared to observations of translucent molecular clouds. We show that the observed populations of rotational levels of H2 can arise as a consequence of the multi-phase structure of the ISM.
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Characterization and Physical Explanation of Energetic Particles on Planck HFI Instrument: The Planck High Frequency Instrument (HFI) has been surveying the sky continuously from the second Lagrangian point (L2) between August 2009 and January 2012. It operates with 52 high impedance bolometers cooled at 100mK in a r...
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Stellar distances from spectroscopic observations: a new technique: A Bayesian approach to the determination of stellar distances from photometric and spectroscopic data is presented and tested both on pseudodata, designed to mimic data for stars observed by the RAVE survey, and on the real stars from the Geneva-Copenh...
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4MOST - 4-metre Multi-Object Spectroscopic Telescope: The 4MOST consortium is currently halfway through a Conceptual Design study for ESO with the aim to develop a wide-field (>3 square degree, goal >5 square degree), high-multiplex (>1500 fibres, goal 3000 fibres) spectroscopic survey facility for an ESO 4m-class tele...
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Creating A Galactic Plane Atlas With Amazon Web Services: This paper describes by example how astronomers can use cloud-computing resources offered by Amazon Web Services (AWS) to create new datasets at scale. We have created from existing surveys an atlas of the Galactic Plane at 16 wavelengths from 1 {\mu}m to 24 {\m...
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Driving unmodelled gravitational-wave transient searches using astrophysical information: Transient gravitational-wave searches can be divided into two main families of approaches: modelled and unmodelled searches, based on matched filtering techniques and time-frequency excess power identification respectively. The ...
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Speckle Suppression Through Dual Imaging Polarimetry, and a Ground-Based Image of the HR 4796A Circumstellar Disk: We demonstrate the versatility of a dual imaging polarimeter working in tandem with a Lyot coronagraph and Adaptive Optics to suppress the highly static speckle noise pattern--the greatest hindrance to g...
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Wide-band Profile Domain Pulsar Timing Analysis: We extend profile domain pulsar timing to incorporate wide-band effects such as frequency-dependent profile evolution and broadband shape variation in the pulse profile. We also incorporate models for temporal variations in both pulse width and in the separation in phase...
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Microarcsecond VLBI pulsar astrometry with PSR$π$ II. parallax distances for 57 pulsars: We present the results of PSR$\pi$, a large astrometric project targeting radio pulsars using the Very Long Baseline Array (VLBA). From our astrometric database of 60 pulsars, we have obtained parallax-based distance measurements...
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The Design and Performance of IceCube DeepCore: The IceCube neutrino observatory in operation at the South Pole, Antarctica, comprises three distinct components: a large buried array for ultrahigh energy neutrino detection, a surface air shower array, and a new buried component called DeepCore. DeepCore was designed to...
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Radio Astronomy Data Transfer and eVLBI using KAREN: Kiwi Advanced Research and Education Network (KAREN) has been used to transfer large volumes of radio astronomical data between the Radio Astronomical Observatory at Warkworth, New Zealand and various international organizations involved in joint projects and VLBI ob...
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CUTE solutions for two-point correlation functions from large cosmological datasets: In the advent of new large galaxy surveys, which will produce enormous datasets with hundreds of millions of objects, new computational techniques are necessary in order to extract from them any two-point statistic, the computational...
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Using the Astrophysics Source Code Library: Find, cite, download, parse, study, and submit: The Astrophysics Source Code Library (ASCL) contains 3000 metadata records about astrophysics research software and serves primarily as a registry of software, though it also can and does accept code deposit. Though the ASCL w...
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MAGIC-II Camera Slow Control Software: The Imaging Atmospheric Cherenkov Telescope MAGIC I has recently been extended to a stereoscopic system by adding a second 17 m telescope, MAGIC-II. One of the major improvements of the second telescope is an improved camera. The Camera Control Program is embedded in the telescope...
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On the use of asymmetric PSF on NIR images of crowded stellar fields: We present data collected using the camera PISCES coupled with the Firt Light Adaptive Optics (FLAO) mounted at the Large Binocular Telescope (LBT). The images were collected using two natural guide stars with an apparent magnitude of R<13 mag. Durin...
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The ATA Digital Processing Requirements are Driven by RFI Concerns: As a new generation radio telescope, the Allen Telescope Array (ATA) is a prototype for the square kilometer array (SKA). Here we describe recently developed design constraints for the ATA digital signal processing chain as a case study for SKA process...
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Measurement of South Pole ice transparency with the IceCube LED calibration system: The IceCube Neutrino Observatory, approximately 1 km^3 in size, is now complete with 86 strings deployed in the Antarctic ice. IceCube detects the Cherenkov radiation emitted by charged particles passing through or created in the ice....
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Multiplexing lobster-eye optics: a concept for wide-field X-ray monitoring: We propose a concept of multiplexing lobster-eye (MuLE) optics to achieve significant reductions in the number of focal plane imagers in lobster-eye (LE) wide-field X-ray monitors. In the MuLE configuration, an LE mirror is divided into sever...
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Multi-messenger Astronomy: a Bayesian approach: After the discovery of the gravitational waves and the observation of neutrinos of cosmic origin, we have entered a new and exciting era where cosmic rays, neutrinos, photons and gravitational waves will be used simultaneously to study the highest energy phenomena in the ...
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Proximity Operators for Phase Retrieval: We present a new formulation of a family of proximity operators that generalize the projector step for phase retrieval. These proximity operators for noisy intensity measurements can replace the classical "noise free" projection in any projection-based algorithm. They are derive...
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Progress with the LOFAR Imaging Pipeline: One of the science drivers of the new Low Frequency Array (LOFAR) is large-area surveys of the low-frequency radio sky. Realizing this goal requires automated processing of the interferometric data, such that fully calibrated images are produced by the system during survey oper...
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Diffractive Microlensing: A New Probe of the Local Universe: Diffraction is important when nearby substellar objects gravitationally lens distant stars. If the wavelength of the observation is comparable to the Schwarzschild radius of lensing object, diffraction leaves an observable imprint on the lensing signature. Th...
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Compensation of tropospheric and ionospheric effects in gravitational sessions of the spacecraft RadioAstron: The possibility of compensating atmospheric influence in an experiment on precision measurement of gravitational redshift using the "RadioAstron" spacecraft (SC) is discussed. When a signal propagates from a ...
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RISTRETTO: coronagraph and AO designs enabling High Dispersion Coronagraphy at 2 lambda/D: RISTRETTO is the evolution of the original idea of coupling the VLT instruments SPHERE and ESPRESSO, aiming at High Dispersion Coronagraphy. RISTRETTO is a visitor instrument that should enable the characterization of the atmos...
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The angular resolution of GRAPES-3 EAS array after correction for the shower front curvature: The angular resolution of an extensive air shower (EAS) array plays a critical role in determining its sensitivity for the detection of point $\gamma$-ray sources in the multi-TeV energy range. The GRAPES-3 an EAS array loca...
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The Graphical User Interface of the Operator of the Cherenkov Telescope Array: The Cherenkov Telescope Array (CTA) is the next generation gamma-ray observatory. CTA will incorporate about 100 imaging atmospheric Cherenkov telescopes (IACTs) at a southern site, and about 20 in the north. Previous IACT experiments have...
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Gemini Planet Imager Observational Calibrations II: Detector Performance and Calibration: The Gemini Planet Imager is a newly commissioned facility instrument designed to measure the near-infrared spectra of young extrasolar planets in the solar neighborhood and obtain imaging polarimetry of circumstellar disks. GPI'...
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First tests of a 1 megapixel near-infrared avalanche photodiode array for ultra-low background space astronomy: Spectroscopy of Earth-like exoplanets and ultra-faint galaxies are priority science cases for the coming decades. Here, broadband source flux rates are measured in photons per square meter per hour, imposin...
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Temporal spectrum of multi-conjugate adaptive optics residuals and impact of tip-tilt anisoplanatism on astrometric observations: Multi-conjugate adaptive optics (MCAO) will assist a new era of ground-based astronomical observations with the extremely large telescopes and the Very Large Telescope. High precision rela...
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Physical properties of the interstellar medium using high-resolution Chandra spectra: O K-edge absorption: Chandra high-resolution spectra toward eight low-mass Galactic binaries have been analyzed with a photoionization model that is capable of determining the physical state of the interstellar medium. Particular at...
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Upgrading electron temperature and electron density diagnostic diagrams of forbidden line emission: Diagnostic diagrams of forbidden lines have been a useful tool for observers in astrophysics for many decades now. They are used to obtain information on the basic physical properties of thin gaseous nebulae. Some diag...
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Time-Dependent Behavior of Linear Polarization in Unresolved Photospheres, With Applications for The Hanle Effect: Aims: This paper extends previous studies in modeling time varying linear polarization due to axisymmetric magnetic fields in rotating stars. We use the Hanle effect to predict variations in net line pol...
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