Latest in astro-ph.im

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Calibrating gravitational-wave detectors with GW170817Feb 21 2019The waveform of a compact binary coalescence is predicted by general relativity. It is therefore possible to directly constrain the response of a gravitational-wave (GW) detector by analyzing a signal's observed amplitude and phase evolution as a function ... More
Towards the forecast of atmospheric parameters and optical turbulence above an astronomical site on 24h time scaleFeb 21 2019Forecast of the atmospheric parameters and optical turbulence applied to the ground-based astronomy is very crucial mainly for the queue scheduling. So far, most efforts have been addressed by our group in developing algorithms for the optical turbulence ... More
Evaluation of filtering techniques to increase the reliability of meteo forecasts for ground-based telescopesFeb 21 2019In this contribution we evaluate the impact of filtering techniques in enhancing the accuracy of forecasts of optical turbulence and atmospheric parameters critical for ground-based telescopes. These techniques make use of the data continuously provided ... More
Ultra-Stable Environment Control for the NEID Spectrometer: Design and Performance DemonstrationFeb 20 2019Two key areas of emphasis in contemporary experimental exoplanet science are the detailed characterization of transiting terrestrial planets, and the search for Earth analog planets to be targeted by future imaging missions. Both of these pursuits are ... More
First results on sub-GeV spin-dependent dark matterFeb 20 2019In this work, we want to highlight the potential of lithium as a target for spin-dependent dark matter search in cryogenic experiments, with a special focus on the low-mass region of the parameter space. We operated a prototype detector module based on ... More
Detection of a 14-days atmospheric perturbation peak at Paranal associated with lunar cyclesFeb 19 2019In this paper we investigate the correlation between the atmospheric perturbations at Paranal Observatory and the Chilean coast tides, which are mostly modulated by the 14-day syzygy solar-lunar tidal cycle. To this aim, we downloaded 15 years (2003-2017) ... More
Feature Selection for Better Spectral Characterization or: How I Learned to Start Worrying and Love EnsemblesFeb 19 2019An ever-looming threat to astronomical applications of machine learning is the danger of over-fitting data, also known as the `curse of dimensionality.' This occurs when there are fewer samples than the number of independent variables. In this work, we ... More
The solar survey at Pic du Midi: calibrated data and improved imagesFeb 19 2019At Pic du Midi observatory we carry a solar survey with images of the photosphere, prominences and corona. This survey, CLIMSO, is in the following spectral lines: Fe~XIII corona (1.075~$\mu$m), H-$\alpha$ (656.3~nm) and He~I (1.083~$\mu$m) prominences, ... More
Robbie: A Batch Processing Work-flow for the Detection of Radio Transients andVariablesFeb 19 2019We present Robbie: a general work-flow for the detection and characterization of radio variability and transient events in the image domain. Robbie is designed to work in a batch processing paradigm with a modular design so that components can be swapped ... More
Background for a gamma-ray satellite on a low-Earth orbitFeb 19 2019The different background components in a low-Earth orbit have been modeled in the 10 keV to 100 GeV energy range. The model is based on data from previous instruments and it considers both primary and secondary particles, charged particles, neutrons and ... More
Model-free inverse method for transit imaging of stellar surfaces: Using transit surveys to map stellar spot coverageFeb 18 2019Context. We present a model-free method for mapping surface brightness variations. Aims. We aim to develop a method that is not dependent on either stellar atmosphere models or limb-darkening equation. This method is optimized for exoplanet transit surveys ... More
Terahertz Atmospheric Windows for High Angular Resolution Terahertz Astronomy from Dome AFeb 18 2019Atmospheric transmission from Dome A, Antarctica, presents new possibilities in the field of terahertz astronomy, where space telescopes have been the only observational tools until now. Using atmospheric transmission measurements from Dome A with a Fourier ... More
Towards deeper neural networks for Fast Radio Burst detectionFeb 17 2019With the upcoming commensal surveys for Fast Radio Bursts (FRBs), and their high candidate rate, usage of machine learning algorithms for candidate classification is a necessity. Such algorithms will also play a pivotal role in sending real-time triggers ... More
First-light images from low dispersion spectrograph-cum-imager on 3.6-meter Devasthal Optical TelescopeFeb 15 2019A low dispersion spectrograph-cum-imager has been developed and assembled in ARIES, Nainital. The optical design of the spectrograph consists of a collimator and a focal reducer converting the f/9 beam from the 3.6-m Devasthal optical telescope to a nearly ... More
The Wide Field Infrared Survey Telescope: 100 Hubbles for the 2020sFeb 14 2019The Wide Field Infrared Survey Telescope (WFIRST) is a 2.4m space telescope with a 0.281 deg^2 field of view for near-IR imaging and slitless spectroscopy and a coronagraph designed for > 10^8 starlight suppresion. As background information for Astro2020 ... More
Kernel formalism applied to Fourier based Wave Front Sensing in presence of residual phasesFeb 14 2019In this paper, we show how it is possible to understand Fourier-based Wave Front Sensors (WFS) as Linear Integral Operators. Indeed optical laws allow to identify quantities called "Kernels" which are the continuous version of well-known interaction matrices ... More
Transparent tiles of silica aerogels for high-energy physicsFeb 14 2019Silica aerogels are important to be used as photon radiators in Cherenkov counters for high-energy-physics experiments because of their optical transparency and intermediate refractive indices between those of gases and liquids or solids. Cherenkov counters ... More
A Proposed Method for a Photon-Counting Laser Coherence Detection System to Complement Optical SETIFeb 14 2019The detection of laser radiation originating from space is a positive indicator of Extra Terrestrial Intelligence (ETI). Thus far the optical search for ETI (OSETI) has looked for enhanced brightness in the form of either narrow-band spectral emission ... More
A Comparison of Photometric Redshift Techniques for Large Radio SurveysFeb 14 2019Future radio surveys will generate catalogues of tens of millions of radio sources, for which redshift estimates will be essential to achieve many of the science goals. However, spectroscopic data will be available for only a small fraction of these sources, ... More
Discovery of Strongly-lensed Gravitational Waves - Implications for the LSST Observing StrategyFeb 13 2019LSST's wide-field of view and sensitivity will revolutionize studies of the transient sky by finding extraordinary numbers of new transients every night. The recent discovery of a kilonova counterpart to LIGO/Virgo's first detection of gravitational waves ... More
Accelerating parameter inference with graphics processing unitsFeb 13 2019Gravitational wave Bayesian parameter inference involves repeated comparisons of GW data to generic candidate predictions. Even with algorithmically efficient methods like RIFT or reduced-order quadrature, the time needed to perform these calculations ... More
Scattered moonlight observations with X-Shooter: Implications for the aerosol properties at Cerro Paranal and the ESO sky background modelFeb 12 2019Estimating the sky background is critical for ground-based astronomical research. In the optical, scattered moonlight dominates the sky background, when the moon is above the horizon. The most uncertain component of a scattered moonlight model is the ... More
Can supernova kicks trigger EMRIs in the Galactic Centre?Feb 12 2019One of the most promising gravitational wave (GW) sources detectable by the forthcoming LISA observatory are the so-called extreme-mass ratio inspirals (EMRIs), i.e. GW-driven inspirals of stellar-mass compact objects onto supermassive black holes (SMBHs). ... More
Test of Einstein equivalence principle near the Galactic center supermassive black holeFeb 12 2019During its orbit around the four million solar mass black hole Sagittarius A* the star S2 experiences significant changes in gravitational potential. We use this change of potential to test one part of the Einstein equivalence principle: the local position ... More
Automatic Selection of CDS Timing ParametersFeb 11 2019CDS is a process used in many \ac{CCD} readout systems to cancel the reset noise component that would otherwise dominate. CDS processing typically consists of subtracting the integrated video signal during a "signal" period from that during a "reset" ... More
Low Cost Radiation Hardened Software and Hardware Implementation for CubeSatsFeb 11 2019CubeSats are small satellites used for scientific experiments because they cost less than full sized satellites. Each CubeSat uses an on-board computer. The on-board computer performs sensor measurements, data processing, and CubeSat control. The challenges ... More
AGN selection in the AKARI NEP deep field with the fuzzy SVM algorithmFeb 11 2019The aim of this work is to create a new catalog of reliable AGN candidates selected from the AKARI NEP-Deep field. Selection of the AGN candidates was done by applying a fuzzy SVM algorithm, which allows to incorporate measurement uncertainties into the ... More
ISPY - the NaCo Imaging Survey for Planets around Young stars: A young companion candidate embedded in the R CrA cloudFeb 11 2019Within the NaCo-ISPY exoplanet imaging program, we aim at detecting and characterizing the population of low-mass companions at wide separations ($\gtrsim$10AU), focusing in particular on young stars either hosting a known protoplanetary disk or a debris ... More
Convolutional Neural Networks on the HEALPix sphere: a pixel-based algorithm and its application to CMB data analysisFeb 11 2019We describe a novel method for the application of Convolutional Neural Networks (CNNs) to fields defined on the sphere, using the HEALPix tessellation scheme. Specifically, We have developed a pixel-based approach to implement convolutional layers on ... More
SPHERE: the exoplanet imager for the Very Large TelescopeFeb 11 2019Observations of circumstellar environments to look for the direct signal of exoplanets and the scattered light from disks has significant instrumental implications. In the past 15 years, major developments in adaptive optics, coronagraphy, optical manufacturing, ... More
Search for dark matter with a 231-day exposure of liquid argon using DEAP-3600 at SNOLABFeb 11 2019DEAP-3600 is a single-phase liquid argon (LAr) direct-detection dark matter experiment, operating 2 km underground at SNOLAB (Sudbury, Canada). The detector consists of 3279 kg of LAr contained in a spherical acrylic vessel. This paper reports on the ... More
Quantifying tension: interpreting the DES evidence ratioFeb 11 2019We provide a new interpretation for the Bayes factor combination used in the DES first year analysis to quantify the tension between the Dark Energy Survey (DES) and Planck datasets. The ratio quantifies a Bayesian confidence in our ability to combine ... More
Precipitable Water Vapor, Temperature, and Wind Statistics At Sites Suitable for mm and Submm Wavelength Astronomy in Northern ChileFeb 11 2019Atmospheric water vapor is the main limiting factor of atmospheric transparency in the mm and submm wavelength spectral windows. Thus, dry sites are needed for the installation and successful operation of radio astronomy observatories exploiting those ... More
Constraints on the ultra-high energy cosmic neutrino flux from the fourth flight of ANITAFeb 11 2019The ANtarctic Impulsive Transient Antenna (ANITA) NASA long-duration balloon payload completed its fourth flight in December 2016, after 28 days of flight time. ANITA is sensitive to impulsive broadband radio emission from interactions of ultra-high-energy ... More
On the optimum operating conditions of ThNe calibration lamps for measurements of radial velocity variationsFeb 11 2019Previous studies have shown that ThNe lamps are very suitable for the precise measurement of wavelength variations. A critical issue for all hollow cathode lamps (HCL) is the current at which the lamp is operated - a low value has the advantage that the ... More
Zenith angle dependence of the cosmic ray rate as measured with Imaging air-Cherenkov TelescopesFeb 11 2019The rate of extensive air-showers observed with imaging air-Cherenkov telescopes is zenith angle dependent. This effect originates from the increasing geometrical distance of the observed shower to the telescope with increasing zenith distance. This paper ... More
Fast Evaluation of Low-Thrust Transfers via Deep Neural NetworksFeb 11 2019The design of low-thrust-based multitarget interplanetary missions requires a method to quickly and accurately evaluate the low-thrust transfer between any two visiting targets. Complete evaluation of the low-thrust transfer includes not only the estimation ... More
Should $N$-body integrators be symplectic everywhere in phase space?Feb 10 2019Symplectic integrators are the preferred method of solving conservative $N$-body problems in cosmological, stellar cluster, and planetary system simulations because of their superior error properties and ability to compute orbital stability. Newtonian ... More
The Physics of the Accelerating Universe CameraFeb 10 2019The PAU (Physics of the Accelerating Universe) Survey goal is to obtain photometric redshifts (photo-z) and Spectral Energy Distribution (SED) of astronomical objects with a resolution roughly one order of magnitude better than current broad band photometric ... More
Deep learning detection of transientsFeb 10 2019The next generation of observatories will facilitate the discovery of new types of astrophysical transients. The detection of such phenomena, whose characteristics are presently poorly constrained, will hinge on the ability to perform blind searches. ... More
Propelling Interplanetary Spacecraft Utilizing Water-SteamFeb 10 2019Water has been identified as a critical resource both to sustain human-life but also for use in propulsion, attitude-control, power, thermal and radiation pro-tection systems. Water may be obtained off-world through In-Situ Resource Utilization (ISRU) ... More
Recognition of M-type stars in the unclassified spectra of LAMOST DR5 using a hash learning methodFeb 09 2019Our study aims to recognize M-type stars which are classified as "UNKNOWN" due to bad quality in Large sky Area Multi-Object fibre Spectroscopic Telescope (LAMOST) DR5 V1. A binary nonlinear hashing algorithm based on Multi-Layer Pseudo Inverse Learning ... More
The mass distribution of Galactic double neutron starsFeb 08 2019The conventional wisdom dating back to 2012 is that the mass distribution of Galactic double neutron stars is well-fit by a Gaussian distribution with a mean of $1.33 M_\odot$ and a width of $0.09 M_\odot$. With the recent discovery of new Galactic double ... More
High Performance Computing for gravitational lens modeling: single vs double precision on GPUs and CPUsFeb 08 2019Strong gravitational lensing is a powerful probe of cosmology and the dark matter distribution. Efficient lensing software is already a necessity to fully use its potential and the performance demands will only increase with the upcoming generation of ... More
An Autonomous Passive Navigation Method for Nanosatellite Exploration of the Asteroid BeltFeb 08 2019There are more than 750,000 asteroids identified in the main belt. These asteroids are diverse in composition and size. Some of these asteroids can be traced back to the early solar system and can provide insight into the origins of the so-lar system, ... More
$\texttt{simsurvey}$: Estimating Transient Discovery Rates for the Zwicky Transient FacilityFeb 08 2019When planning a survey for astronomical transients, many factors such as cadence, filter choice, sky coverage, and depth of observations need to be balanced in order to optimize the scientific gain of the survey. Here we present a software package called ... More
Non-stationary variability in accreting compact objectsFeb 08 2019Accreting compact objects show variations in source flux over a broad range of timescales and in all wavebands. The light curves typically show a lognormal distribution of flux and a linear relation between flux and rms. It has been demonstrated that ... More
The ALMA Development RoadmapFeb 07 2019The present document outlines a roadmap for future developments that will significantly expand ALMA's capabilities and enable it to produce even more exciting science in the coming decades. The proposed developments are motivated by the groundbreaking ... More
CORSIKA 8 - Towards a modern framework for the simulation of extensive air showersFeb 07 2019Current and future challenges in astroparticle physics require novel simulation tools to achieve higher precision and more flexibility. For three decades the FORTRAN version of CORSIKA served the community in an excellent way. However, the effort to maintain ... More
A 30 GHz electro-optic frequency comb spanning 300 THz in the near infrared and visibleFeb 07 2019Beginning with a continuous wave laser at 1064 nm, we generate a 30 GHz electro-optic frequency comb which contains 100 lines spanning 3 THz. The initial comb is subsequently amplified, spectrally broadened in normal dispersion photonic crystal fiber, ... More
A new HLLD Riemann solver with Boris correction for reducing Alfvén speedFeb 07 2019A new Riemann solver is presented for the ideal magnetohydrodynamics (MHD) equations with the so-called Boris correction. The Boris correction is applied to reduce wave speeds, avoiding an extremely small timestep in MHD simulations. The proposed Riemann ... More
Lunar impacts during eclipses separated by a Metonic cycle on Jan 21, 2000 and 2019: a possible origin from daytime Sagittarids/Capriconids meteor showerFeb 07 2019The lunar impact claimed by Zuluaga et al. (2019) during the total eclipse of 21 January has been discussed widely by his research group, introducing some results from the technique of gravitational ray-tracing. A similar event of magnitude 6 was observed ... More
Dense Particle Clouds in Laboratory Experiments in Context of Drafting and Streaming InstabilityFeb 07 2019The streaming instability, as an example of instabilities driven by particle feedback on a gas flow, has been proven to have a major role in controlling the formation of planetesimals. Here, we present experiments to approach this situation in the laboratory ... More
Stellar Formation Rates for photometric samples of galaxies using machine learning methodsFeb 07 2019Feb 08 2019Stellar Formation Rates or SFRs are crucial to constrain theories of galaxy formation and evolution. SFRs are usually estimated via spectroscopic observations requiring large amounts of telescope time. We explore an alternative approach based on the photometric ... More
Stellar Formation Rates for photometric samples of galaxies using machine learning methodsFeb 07 2019Stellar Formation Rates or SFRs are crucial to constrain theories of galaxy formation and evolution. SFRs are usually estimated via spectroscopic observations requiring large amounts of telescope time. We explore an alternative approach based on the photometric ... More
On Identifiability and Estimability of Direction Dependent Calibration of Radio Interferometric ArraysFeb 07 2019Calibration is a key step in the signal processing pipeline of any radio astronomical instrument. The required sky, ionospheric and instrumental models for this step can suffer from various kinds of incompleteness. In this paper we analyze several important ... More
Machine Vision and Deep Learning for Classification of Radio SETI SignalsFeb 06 2019We apply classical machine vision and machine deep learning methods to prototype signal classifiers for the search for extraterrestrial intelligence. Our novel approach uses two-dimensional spectrograms of measured and simulated radio signals bearing ... More
Photometric Biases in Modern SurveysFeb 06 2019Most surveys use maximum-likelihood (ML) methods to fit models when extracting photometry from images. We show these ML estimators systematically overestimate the flux as a function of the signal-to-noise ratio (SNR) and the number of model parameters ... More
Distances and parallax bias in Gaia DR2Feb 06 2019We derive Bayesian distances for all stars in the RV sample of Gaia DR2, and use the statistical method of Schoenrich, Binney & Asplund(2012) to validate the distances and test the Gaia parallaxes. In contrast to other methods, which rely on special sources, ... More
SI Toolbox - Full documentationFeb 06 2019I Toolbox is a package for estimating the isotropy violation in the CMB sky. It ca be used for estimating the BipoSH coefficients, Dipole modulation, and Doppler boost parameters etc. Different Fortran subroutines, provided with this package, can help ... More
Principal Component Analysis of Up-the-ramp Sampled IR Array DataFeb 06 2019We describe the results of principal component analysis (PCA) of up-the-ramp sampled IR array data from the HST WFC3 IR, JWST NIRSpec, and prototype WFIRST WFI detectors. These systems use respectively Teledyne H1R, H2RG, and H4RG-10 near-IR detector ... More
The Zwicky Transient Facility Alert Distribution SystemFeb 06 2019The Zwicky Transient Facility (ZTF) survey generates real-time alerts for optical transients, variables, and moving objects discovered in its wide-field survey. We describe the ZTF alert stream distribution and processing (filtering) system. The system ... More
The Pégase.3 code of spectrochemical evolution of galaxies: documentation and complementsFeb 06 2019P\'egase.3 is a Fortran 95 code modeling the spectral evolution of galaxies from the far-ultraviolet to submillimeter wavelengths. It also follows the chemical evolution of their stars, gas and dust. For a given scenario (a set of parameters defining ... More
Spacecraft Swarm Attitude Control for Small Body Surface ObservationFeb 06 2019Understanding the physics of small bodies such as asteroids, comets, and planetary moons will help us understand the formation of the solar system, and also provide us with resources for a future space economy. Due to these reasons, missions to small ... More
Attitude Control of an Inflatable Sailplane for Mars ExplorationFeb 06 2019Feb 07 2019Exploration of Mars has been made possible using a series of landers, rovers and orbiters. The HiRise camera on the Mars Reconnaissance Orbiter (MRO) has captured high-resolution images covering large tracts of the surface. However, orbital images lack ... More
Attitude Control of an Inflatable Sailplane for Mars ExplorationFeb 06 2019Feb 15 2019Exploration of Mars has been made possible using a series of landers, rovers and orbiters. The HiRise camera on the Mars Reconnaissance Orbiter (MRO) has captured high-resolution images covering large tracts of the surface. However, orbital images lack ... More
Guidance, Navigation and Control of Asteroid Mobile Imager and Geologic Observer (AMIGO)Feb 06 2019The science and origins of asteroids is deemed high priority in the Planetary Science Decadal Survey. Major scientific goals for the study of planetesimals are to decipher geological processes in SSSBs not determinable from investigation via in-situ experimentation, ... More
Motion Planning on an Asteroid Surface with Irregular Gravity FieldsFeb 06 2019There are thousands of asteroids in near-Earth space and millions in the Main Belt. They are diverse in physical properties and composition and are time capsules of the early solar system. This makes them strategic locations for planetary science, resource ... More
The Zwicky Transient Facility: Science ObjectivesFeb 05 2019The Zwicky Transient Facility (ZTF), a public-private enterprise, is a new time domain survey employing a dedicated camera on the Palomar 48-inch Schmidt telescope with a 47 deg$^2$ field of view and 8 second readout time. It is well positioned in the ... More
Machine Learning for the Zwicky Transient FacilityFeb 05 2019The Zwicky Transient Facility is a large optical survey in multiple filters producing hundreds of thousands of transient alerts per night. We describe here various machine learning (ML) implementations and plans to make the maximal use of the large data ... More
A Morphological Classification Model to Identify Unresolved PanSTARRS1 Sources: Application in the ZTF Real-Time PipelineFeb 05 2019In the era of large photometric surveys, the importance of automated and accurate classification is rapidly increasing. Specifically, the separation of resolved and unresolved sources in astronomical imaging is a critical initial step for a wide array ... More
The GROWTH Marshal: A Dynamic Science Portal for Time-Domain AstronomyFeb 05 2019We describe a dynamic science portal called the GROWTH Marshal that allows time-domain astronomers to define science programs, program filters to save sources from different discovery streams, co-ordinate follow-up with various robotic or classical telescopes, ... More
The Zwicky Transient Facility: System Overview, Performance, and First ResultsFeb 05 2019The Zwicky Transient Facility (ZTF) is a new optical time-domain survey that uses the Palomar 48-inch Schmidt telescope. A custom-built wide-field camera provides a 47 deg$^2$ field of view and 8 second readout time, yielding more than an order of magnitude ... More
Dark Hole Maintenance and A Posteriori Intensity Estimation in the Presence of Speckle Drift in a High-Contrast Space CoronagraphFeb 05 2019Direct exoplanet imaging via coronagraphy requires maintenance of high contrast in a dark hole for lengthy integration periods. Wavefront errors that change slowly over that time accumulate and cause systematic errors in the star's Point Spread Function ... More
The Zwicky Transient Facility: Data Processing, Products, and ArchiveFeb 05 2019The Zwicky Transient Facility (ZTF) is a new robotic time-domain survey currently in progress using the Palomar 48-inch Schmidt Telescope. ZTF uses a 47 square degree field with a 600 megapixel camera to scan the entire northern visible sky at rates of ... More
Radio detection in the multi-messenger contextFeb 05 2019The present work discusses the development of the radio technique for detection of ultra-high energy air-showers induced by cosmic radiation, and the prospects of its application in the future multi-messenger activities, particularly for detection of ... More
rPICARD: A CASA-based Calibration Pipeline for VLBI Data. Calibration and imaging of 7 mm VLBA observations of the AGN jet in M87Feb 05 2019(Abridged) With the recent addition of a fringe-fitter, the Common Astronomy Software Application (CASA) software suite, the current state of the art package for radio astronomy can now reduce VLBI data. Here, we present the Radboud PIpeline for the Calibration ... More
A new line on the wide binary test of gravityFeb 05 2019The relative velocity distribution of wide binary (WB) stars is sensitive to the law of gravity at the low accelerations typical of galactic outskirts. I consider the feasibility of this wide binary test using the `line velocity' method. This involves ... More
Mapping the stellar age of the Milky Way bulge with the VVV. I. The methodFeb 05 2019Recent observational programmes are providing a global view of the Milky Way bulge that serves as template for detailed comparison with models and extragalactic bulges. A number of surveys (i.e. VVV, GIBS, GES, ARGOS, BRAVA, APOGEE) are producing comprehensive ... More
Climbing Halo Merger Trees with TreeFrogFeb 05 2019We present TreeFrog, a massively parallel halo merger tree builder that is capable comparing different halo catalogues and producing halo merger trees. The code is written in c++11, use the MPI and OpenMP API's for parallelisation, and includes python ... More
Phased Array Feed Model Equations corresponding to two definitions of embedded beam patternFeb 05 2019In this report, we present the phased array feed (PAF) model equations for two definitions of embedded beam patterns. In Roshi \& Fisher (2016), we presented the PAF model by defining the embedded beam pattern as the beam pattern due to a 1 V excitation ... More
A Model for Phased Array FeedFeb 05 2019In this report we present a model for phased array feed (PAF) and compare the model predictions with measurements. A theory for loss-less PAF is presented first. To develop the theory we ask the question -- what is the best $T_{sys}/\eta_{ap}$ that can ... More
Model for a Noise Matched Phased Array FeedFeb 05 2019Feb 06 2019We present a model for a Noise Matched Phased Array Feed (PAF) system and compare model predictions with the measurement results. The PAF system consists of an array feed, a receiver, a beamformer and a parabolic reflector. The novel aspect of our model ... More
Optical and Opto-Mechanical Design of a Novel "Macro" Image Slicer for the MIRADAS InstrumentFeb 04 2019We present the innovative macro-slicer optical and opto-mechanical designs for the third-generation Mid-resolution InfraReD Astronomical Spectrograph (MIRADAS) instrument for the 10.4m Gran Telescopio Canarias (GTC) in the 1-2.5 $\mu$m bandpass. MIRADAS ... More
ALMA FITS header keywords: a study from the archive User perspectiveFeb 04 2019ALMA products are stored in the Science Archive in the form of FITS images. It is a common idea that the FITS image headers should collect in their keywords all the information that an archive User might want to search for in order to quickly select, ... More
Improvement of Simplified Models of Variability of Stars: A reviewFeb 03 2019Astronomical data are typically irregular in time, e.g. the space (HIPPARCOS/TYCHO, KEPLER, GAIA, WISE etc.) and ground-based CCD (NSVS, ASAS, CRTS, SuperWASP etc.) and photographic (Harvard, Sonneberg, Odessa etc.) photometrical surveys. This leads to ... More
Towards an overall astrometric error budget with MICADO-MCAOFeb 03 2019MICADO is the Multi-AO Imaging Camera for Deep Observations, and it will be one of the first light instruments of the Extremely Large Telescope (ELT). Doing high precision multi-object differential astrometry behind ELT is particularly effective given ... More
The Apache Point Observatory Galactic Evolution Experiment (APOGEE) SpectrographsFeb 03 2019We describe the design and performance of the near-infrared (1.51--1.70 micron), fiber-fed, multi-object (300 fibers), high resolution (R = lambda/delta lambda ~ 22,500) spectrograph built for the Apache Point Observatory Galactic Evolution Experiment ... More
Photodetachment and Photoreactions of Substituted Naphthalene Anions in a Tandem Ion Mobility SpectrometerFeb 03 2019Substituted naphthalene anions (deprotonated 2-naphthol and 6-hydroxy-2-naphthoic acid) are spectroscopically probed in a tandem drift tube ion mobility spectrometer (IMS). Target anions are selected according to their drift speed through nitrogen buffer ... More
Bandpass mismatch error for satellite CMB experiments II: Correcting for the spurious signalFeb 01 2019Feb 08 2019Future Cosmic Microwave Background (CMB) satellite missions aim to use the B-mode polarisation signal to measure the tensor-to-scalar ratio $r$ with a sensitivity $\sigma(r)$ of the order of $\leq 10^{-3}$. Small uncertainties in the characterisation ... More
Deep Learning for Multi-Messenger Astrophysics: A Gateway for Discovery in the Big Data EraFeb 01 2019This report provides an overview of recent work that harnesses the Big Data Revolution and Large Scale Computing to address grand computational challenges in Multi-Messenger Astrophysics, with a particular emphasis on real-time discovery campaigns. Acknowledging ... More
Stellar Spectroscopy in the Near-infrared with a Laser Frequency CombFeb 01 2019The discovery and characterization of exoplanets around nearby stars is driven by profound scientific questions about the uniqueness of Earth and our Solar System, and the conditions under which life could exist elsewhere in our Galaxy. Doppler spectroscopy, ... More
Spectangular: Disentangling variable spectraFeb 01 2019Spectangular is a GUI based software package written in C++ designed for spectral disentangling on the wavelength scale. The code disentangles spectra of SB1 and SB2 systems and can now also be used also for spectra showing variability. In this work, ... More
MASER: A Toolbox for Low Frequency Radio AstronomyFeb 01 2019Feb 04 2019MASER (Measurements, Analysis, and Simulation of Emission in the Radio range) is a comprehensive infrastructure dedicated to time-dependent low frequency radio astronomy (up to about 50 MHz). The main radio sources observed in this spectral range are ... More
Using tours to visually investigate properties of new projection pursuit indexes with application to problems in physicsFeb 01 2019Projection pursuit is used to find interesting low-dimensional projections of high-dimensional data by optimizing an index over all possible projections. Most indexes have been developed to detect departure from known distributions, such as normality, ... More
Towards Machine-assisted Meta-Studies: The Hubble ConstantJan 31 2019We present an approach for automatic extraction of measured values from the astrophysical literature, using the Hubble constant for our pilot study. Our rules-based model -- a classical technique in natural language processing -- has successfully extracted ... More
Intensive Monitoring Survey of Nearby Galaxies (IMSNG)Jan 31 2019Intensive Monitoring Survey of Nearby Galaxies (IMSNG) is a high cadence observation program monitoring nearby galaxies with high probabilities of hosting supernovae (SNe). IMSNG aims to constrain the SN explosion mechanism by inferring sizes of SN progenitor ... More
Minerva-Australis I: Design, Commissioning, & First Photometric ResultsJan 31 2019Feb 07 2019The Minerva-Australis telescope array is a facility dedicated to the follow-up, confirmation, characterisation, and mass measurement of bright transiting planets discovered by the Transiting Exoplanet Survey Satellite (TESS) -- a category in which it ... More
Metric Gaussian Variational InferenceJan 30 2019A variational Gaussian approximation of the posterior distribution can be an excellent way to infer posterior quantities. However, to capture all posterior correlations the parametrization of the full covariance is required, which scales quadratic with ... More
PEPITO: atmospheric Profiling from short-Exposure focalPlane Images in seeing-limiTed mOdeJan 30 2019Atmospheric profiling is a requirement for controlling wide-field Adaptive Optics (AO) instruments, analyze the AO performance with respect to the observing conditions and predict the Point Spread Function (PSF) spatial variations. We present PEPITO, ... More