scholarly journals TESS Data for Asteroseismology: Light-curve Systematics Correction

2021 ◽  
Vol 257 (2) ◽  
pp. 53
Author(s):  
Mikkel N. Lund ◽  
Rasmus Handberg ◽  
Derek L. Buzasi ◽  
Lindsey Carboneau ◽  
Oliver J. Hall ◽  
...  
Keyword(s):  
Light Curves ◽  
Intrinsic Variability ◽  
Space Telescopes ◽  
Noise Sources ◽  
Full Spectrum ◽  
Stellar Oscillations ◽  
Science Operations ◽  
Wide Range ◽  
Noise Statistics ◽  
Operations Center

Abstract Data from the Transiting Exoplanet Survey Satellite (TESS) have produced of the order of one million light curves at cadences of 120 s and especially 1800 s for every ∼27 day observing sector during its two-year nominal mission. These data constitute a treasure trove for the study of stellar variability and exoplanets. However, to fully utilize the data in such studies a proper removal of systematic-noise sources must be performed before any analysis. The TESS Data for Asteroseismology group is tasked with providing analysis-ready data for the TESS Asteroseismic Science Consortium, which covers the full spectrum of stellar variability types, including stellar oscillations and pulsations, spanning a wide range of variability timescales and amplitudes. We present here the two current implementations for co-trending of raw photometric light curves from TESS, which cover different regimes of variability to serve the entire seismic community. We find performance in terms of commonly used noise statistics meets expectations and is applicable to a wide range of intrinsic variability types. Further, we find that the correction of light curves from a full sector of data can be completed well within a few days, meaning that when running in steady state our routines are able to process one sector before data from the next arrives. Our pipeline is open-source and all processed data will be made available on the websites of the TESS Asteroseismic Science Operations Center and the Mikulski Archive for Space Telescopes.

An intelligent algorithm for autonomous scientific sampling with the VALKYRIE cryobot

2017 ◽  
Vol 17 (3) ◽  
pp. 247-257 ◽  
Author(s):  
Evan B. Clark ◽  
Nathan E. Bramall ◽  
Brent Christner ◽  
Chris Flesher ◽  
John Harman ◽  
...  
Keyword(s):  
Human Performance ◽  
Autonomous Underwater Vehicles ◽  
Field Performance ◽  
Planetary Science ◽  
Operating Environment ◽  
Intelligent Algorithm ◽  
Future State ◽  
Science Operations ◽  
Wide Range ◽  
Matanuska Glacier

AbstractThe development of algorithms for agile science and autonomous exploration has been pursued in contexts ranging from spacecraft to planetary rovers to unmanned aerial vehicles to autonomous underwater vehicles. In situations where time, mission resources and communications are limited and the future state of the operating environment is unknown, the capability of a vehicle to dynamically respond to changing circumstances without human guidance can substantially improve science return. Such capabilities are difficult to achieve in practice, however, because they require intelligent reasoning to utilize limited resources in an inherently uncertain environment. Here we discuss the development, characterization and field performance of two algorithms for autonomously collecting water samples on VALKYRIE (Very deep Autonomous Laser-powered Kilowatt-class Yo-yoing Robotic Ice Explorer), a glacier-penetrating cryobot deployed to the Matanuska Glacier, Alaska (Mission Control location: 61°42′09.3″N 147°37′23.2″W). We show performance on par with human performance across a wide range of mission morphologies using simulated mission data, and demonstrate the effectiveness of the algorithms at autonomously collecting samples with high relative cell concentration during field operation. The development of such algorithms will help enable autonomous science operations in environments where constant real-time human supervision is impractical, such as penetration of ice sheets on Earth and high-priority planetary science targets like Europa.

scholarly journals Models and data analysis tools for the Solar Orbiter mission

2020 ◽  
Vol 642 ◽  
pp. A2 ◽  
Author(s):  
A. P. Rouillard ◽  
R. F. Pinto ◽  
A. Vourlidas ◽  
A. De Groof ◽  
W. T. Thompson ◽  
...  
Keyword(s):  
Data Analysis ◽  
Solar Disk ◽  
Source Region ◽  
Solar Interior ◽  
The Sun ◽  
Science Operations ◽  
Wide Range ◽  
Tools And Techniques ◽  
Orbiter Mission ◽  
Current Modelling

Context. The Solar Orbiter spacecraft will be equipped with a wide range of remote-sensing (RS) and in situ (IS) instruments to record novel and unprecedented measurements of the solar atmosphere and the inner heliosphere. To take full advantage of these new datasets, tools and techniques must be developed to ease multi-instrument and multi-spacecraft studies. In particular the currently inaccessible low solar corona below two solar radii can only be observed remotely. Furthermore techniques must be used to retrieve coronal plasma properties in time and in three dimensional (3D) space. Solar Orbiter will run complex observation campaigns that provide interesting opportunities to maximise the likelihood of linking IS data to their source region near the Sun. Several RS instruments can be directed to specific targets situated on the solar disk just days before data acquisition. To compare IS and RS, data we must improve our understanding of how heliospheric probes magnetically connect to the solar disk. Aims. The aim of the present paper is to briefly review how the current modelling of the Sun and its atmosphere can support Solar Orbiter science. We describe the results of a community-led effort by European Space Agency’s Modelling and Data Analysis Working Group (MADAWG) to develop different models, tools, and techniques deemed necessary to test different theories for the physical processes that may occur in the solar plasma. The focus here is on the large scales and little is described with regards to kinetic processes. To exploit future IS and RS data fully, many techniques have been adapted to model the evolving 3D solar magneto-plasma from the solar interior to the solar wind. A particular focus in the paper is placed on techniques that can estimate how Solar Orbiter will connect magnetically through the complex coronal magnetic fields to various photospheric and coronal features in support of spacecraft operations and future scientific studies. Methods. Recent missions such as STEREO, provided great opportunities for RS, IS, and multi-spacecraft studies. We summarise the achievements and highlight the challenges faced during these investigations, many of which motivated the Solar Orbiter mission. We present the new tools and techniques developed by the MADAWG to support the science operations and the analysis of the data from the many instruments on Solar Orbiter. Results. This article reviews current modelling and tool developments that ease the comparison of model results with RS and IS data made available by current and upcoming missions. It also describes the modelling strategy to support the science operations and subsequent exploitation of Solar Orbiter data in order to maximise the scientific output of the mission. Conclusions. The on-going community effort presented in this paper has provided new models and tools necessary to support mission operations as well as the science exploitation of the Solar Orbiter data. The tools and techniques will no doubt evolve significantly as we refine our procedure and methodology during the first year of operations of this highly promising mission.

scholarly journals Urban Distributed Acoustic Sensing Using In-Situ Fibre Beneath Bern, Switzerland

2020 ◽  
Author(s):  
Krystyna Smolinski ◽  
Patrick Paitz ◽  
Daniel Bowden ◽  
Pascal Edme ◽  
Felix Kugler ◽  
...  
Keyword(s):  
Spatial Resolution ◽  
Seismic Waves ◽  
Velocity Structure ◽  
Road Traffic ◽  
Hazard Analysis ◽  
Noise Sources ◽  
Acoustic Sensing ◽  
Wide Range ◽  
Distributed Acoustic Sensing

<p>Anticipating the risks natural hazards pose to an urban environment requires an understanding of the shallow Earth structure of the region. While urban infrastructure often hinders the deployment of a traditional seismic array, Distributed Acoustic Sensing (DAS) technology facilitates the use of existing telecommunication fibre-optic cables for seismic observation, with spatial resolution down to the metre scale.</p><p>Through collaboration with the SWITCH foundation, we were able to use existing, in-situ fibres beneath Bern, Switzerland for seismic data acquisition over two weeks, covering a distance of 6 km with a spatial resolution of 2 m. This allowed for not only real-time visualisation of anthropogenic noise sources (e.g. road traffic), but also of the propagation of resulting seismic waves.</p><p>Data is analysed in the time and frequency domain to explore the range of signals captured and to assess the consistency of data quality along the cable. The local velocity structure can be constrained using both noise correlations and deterministic signals excited by traffic.</p><p>Initial results reveal the ability of DAS to capture signals over a wide range of frequencies and distances, and show promise for utilising urban DAS data to perform urban seismic tomography and hazard analysis.</p>

scholarly journals simuG: a general-purpose genome simulator

2019 ◽  
Vol 35 (21) ◽  
pp. 4442-4444 ◽  
Author(s):  
Jia-Xing Yue ◽  
Gianni Liti
Keyword(s):  
Copy Number Variants ◽  
General Purpose ◽  
Supplementary Information ◽  
Nucleotide Polymorphisms ◽  
Bioinformatics Analyses ◽  
Full Spectrum ◽  
Single Nucleotide ◽  
Genomic Variants ◽  
Wide Range ◽  
Simulation Based

Abstract Summary Simulated genomes with pre-defined and random genomic variants can be very useful for benchmarking genomic and bioinformatics analyses. Here we introduce simuG, a lightweight tool for simulating the full-spectrum of genomic variants (single nucleotide polymorphisms, Insertions/Deletions, copy number variants, inversions and translocations) for any organisms (including human). The simplicity and versatility of simuG make it a unique general-purpose genome simulator for a wide-range of simulation-based applications. Availability and implementation Code in Perl along with user manual and testing data is available at https://github.com/yjx1217/simuG. This software is free for use under the MIT license. Supplementary information Supplementary data are available at Bioinformatics online.

scholarly journals Expected performances of the Characterising Exoplanet Satellite (CHEOPS)

2020 ◽  
Vol 635 ◽  
pp. A24 ◽  
Author(s):  
S. Hoyer ◽  
P. Guterman ◽  
O. Demangeon ◽  
S. G. Sousa ◽  
M. Deleuil ◽  
...  
Keyword(s):  
Light Curves ◽  
Field Of View ◽  
Current Status ◽  
Point Spread ◽  
Single Target ◽  
Science Operations ◽  
Spread Function ◽  
And Performance ◽  
Irregular Point

The CHaracterizing ExOPlanet Satellite (CHEOPS) is set to be launched in December 2019 and will detect and characterize small size exoplanets via ultra high precision photometry during transits. CHEOPS is designed as a follow-up telescope and therefore it will monitor a single target at a time. The scientific users will retrieve science-ready light curves of the target that will be automatically generated by the CHEOPS data reduction pipeline of the Science Operations Centre. This paper describes how the pipeline processes the series of raw images and, in particular, how it handles the specificities of CHEOPS data, such as the rotating field of view, the extended irregular point spread function, and the data temporal gaps in the context of the strict photometric requirements of the mission. The current status and performance of the main processing stages of the pipeline, that is the calibration, correction, and photometry, are presented to allow the users to understand how the science-ready data have been derived. Finally, the general performance of the pipeline is illustrated via the processing of representative scientific cases generated by the mission simulator.

scholarly journals About this title - Geological Hazards in the UK: Their Occurrence, Monitoring and Mitigation – Engineering Group Working Party Report

2020 ◽  
Vol 29 (1) ◽  
pp. NP-NP
Author(s):  
D. P. Giles ◽  
J. S. Griffiths
Keyword(s):  
Working Party ◽  
Volcanic Eruptions ◽  
Engineering Geologist ◽  
Geological Hazards ◽  
Geological Time ◽  
Full Spectrum ◽  
The Public ◽  
Wide Range ◽  
The Uk ◽  
Swelling And Shrinking

The UK is perhaps unique globally in that it presents the full spectrum of geological time, stratigraphy and associated lithologies within its boundaries. With this wide range of geological assemblages comes a wide range of geological hazards, whether they be geophysical (earthquakes, effects of volcanic eruptions, tsunami, landslides), geotechnical (collapsible, compressible, liquefiable, shearing, swelling and shrinking soils), geochemical (dissolution, radon and methane gas hazards) or georesource related (coal, chalk and other mineral extraction). An awareness of these hazards and the risks that they pose is a key requirement of the engineering geologist.The Geological Society considered that a Working Party Report would help to put the study and assessment of geohazards into the wider social context, helping the engineering geologist to better communicate the issues concerning geohazards in the UK to the client and the public. This volume sets out to define and explain these geohazards, to detail their detection, monitoring and management and to provide a basis for further research and understanding.

Noise Effects in Perceptual Models

Perception ◽  
1997 ◽  
Vol 26 (1_suppl) ◽  
pp. 44-44
Author(s):  
T D Wickens ◽  
L A Olzak
Keyword(s):  
Visual Perception ◽  
Spatial Frequency ◽  
Signal Detection ◽  
Intrinsic Variability ◽  
Noise Sources ◽  
Third Order ◽  
Noise Effects ◽  
Combination Process ◽  
Delta Sigma ◽  
Visual Phenomena

In studies of visual perception performance is often measured by statistics that are ratios of a perceptual magnitude to its intrinsic variability, most commonly the signal-detection measure d'=delta sigma. Many models for visual phenomena treat the variability sigma as a constant and describe performance exclusively by delta. However, in models for the combination of stimulus attributes, the combination process affects both terms, and an observed d' reflects both delta and sigma. For example, we have shown that masking and configural effects with sinusoidal plaids can be at least partially interpreted as noise effects. We have developed methods to analyse these effects. Through a series of concurrent-response experiments using grating stimuli, some reported at earlier ECVP meetings, we have measured the form and magnitude of the noise sources. Our analysis allows us to model the way that primitive Fourier components (spatial frequency by orientation) are integrated to form second-order or third-order combinations (eg spatial frequency pooled over orientation).

scholarly journals The Visibility of Earth Transits

2004 ◽  
Vol 202 ◽  
pp. 445-447 ◽  
Author(s):  
T. Castellano ◽  
L. Doyle ◽  
D. McIntosh
Keyword(s):  
Laboratory Experiments ◽  
Ecliptic Plane ◽  
Solar Neighborhood ◽  
Geometric Condition ◽  
The Sun ◽  
Intrinsic Variability ◽  
Noise Sources ◽  
Photometric Detection ◽  
The Earth ◽  
Order Of Magnitude

The recent photometric detection of planetary transits of the solar-like star HD 209458 at a distance of 47 parsecs suggest that transits can reveal the presence of Jupiter-size planetary companions in the solar neighborhood (Charbonneau et al. 2000; Henry et al. 2000). Recent space-based transit searches have achieved photometric precision within an order of magnitude of that required to detect the much smaller transit signal of an earth-size planet across a solar-size star. Laboratory experiments in the presence of realistic noise sources have shown that CCDs can achieve photometric precision adequate to detect the 9.6 E-5 dimming of the Sun due to a transit of the Earth (Borucki et al. 1997; Koch et al. 2000). Space-based solar irradiance monitoring has shown that the intrinsic variability of the Sun would not preclude such a detection (Borucki, Scargle, Hudson 1985). Transits of the Sun by the Earth would be detectable by observers that reside within a narrow band of sky positions near the ecliptic plane, if the observers possess current Earth epoch levels of technology and astronomical expertise. A catalog of solar-like stars that satisfy the geometric condition for Earth transit visibility are presented.

scholarly journals Starspot migration in close binaries: A fast parameters evaluation from large sky surveys

2016 ◽  
Vol 12 (S325) ◽  
pp. 274-277
Author(s):  
B. Debski ◽  
S. Zola
Keyword(s):  
Visual Inspection ◽  
Magnetic Activity ◽  
Eclipsing Binaries ◽  
Light Curves ◽  
Close Binaries ◽  
Intrinsic Variability ◽  
Sky Surveys ◽  
Orbital Periods

AbstractWe developed a method that allows to classify the light curves of eclipsing binaries of the W UMa type (EW) with respect to their intrinsic variability. The algorithm measures several features of light curves, such as the amplitude of the O’Connell effect, the separation and location of maxima brightness as well as depths of the minima in subsequent orbital periods. This method is capable of distinguishing systems with presumed magnetic activity present from these without it, as well as recognizing systems with starspots migration and those with other types of intrinsic variability manifestation. The classification is done in an automatic way without a time consuming, visual inspection of light curves.

scholarly journals Constraining the Properties of SNe Ia Progenitors from Light Curves

2011 ◽  
Vol 7 (S281) ◽  
pp. 309-313 ◽  
Author(s):  
B. Sadler ◽  
Peter Hoeflich ◽  
E. Baron ◽  
K. Krisciunas ◽  
G. Folatelli ◽  
...  
Keyword(s):  
Main Sequence ◽  
Light Curves ◽  
Overdetermined System ◽  
Model Calculations ◽  
Common Envelope ◽  
Wide Range ◽  
Accretion Rates ◽  
Type Ia ◽  
Closing The Gap ◽  
Ia Supernovae

AbstractWe present an analysis of high precision V light curves (LC) for 18 local Type Ia supernovae (SNe Ia) as obtained with the same telescope and setup at the Las Campanas Observatory (LCO). This homogeneity provides an intrinsic accuracy of a few hundredths of a magnitude with respect to individual LCs and between different objects. Based on the single degenerate (SD) scenario, we identify patterns which have been predicted by model calculations as signatures of the progenitor and accretion rate which change the explosion energy and the amount of electron capture, respectively. Using these templates as principle components and the overdetermined system of SNe pairs, we reconstruct the properties of progenitors and progenitor systems. All LCO SNe Ia follow the brightness decline relation except 2001ay. After subtraction of the two components, the remaining scatter is reduced to ≈0.01m−0.03m. SNe Ia seem to originate from progenitors with main-sequence masses MMS > 3 M⊙ with the exception of two subluminous SNe Ia with MMS < 2 M⊙. The component analysis indicates a wide range of accretion rates in the progenitor systems closing the gap to accretion induced collapses (AIC). SN1991t-like objects show differences in decline rate (dm15) but no tracers of our secondary parameters. This may point to a different origin such as the double degenerate or pulsating delayed detonation scenarios. SN2001ay does not follow the decline relation. It can be understood in the framework of C-rich white dwarfs (WDs), and this group may produce an anti-Phillips relation. We suggest that this may be a result of a common envelope phase and mixing during central He burning as in SN1987A.

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