scholarly journals Using machine learning for transient classification in searches for gravitational-wave counterparts

2020 ◽  
Vol 497 (2) ◽  
pp. 1320-1331 ◽  
Author(s):  
Cosmin Stachie ◽  
Michael W Coughlin ◽  
Nelson Christensen ◽  
Daniel Muthukrishna
Keyword(s):  
Gravitational Wave ◽  
Classification Performance ◽  
Light Curves ◽  
Wide Field ◽  
Photometric Observations ◽  
Wide Field Of View ◽  
Astronomical Object ◽  
The Many ◽  
Rule Out

ABSTRACT The large sky localization regions offered by the gravitational-wave interferometers require efficient follow-up of the many counterpart candidates identified by the wide field-of-view telescopes. Given the restricted telescope time, the creation of prioritized lists of the many identified candidates becomes mandatory. Towards this end, we use astrorapid, a multiband photometric light-curve classifier, to differentiate between kilonovae, supernovae, and other possible transients. We demonstrate our method on the photometric observations of real events. In addition, the classification performance is tested on simulated light curves, both ideally and realistically sampled. We show that after only a few days of observations of an astronomical object, it is possible to rule out candidates as supernovae and other known transients.

scholarly journals Tiling strategies for optical follow-up of gravitational-wave triggers by telescopes with a wide field of view

2016 ◽  
Vol 592 ◽  
pp. A82 ◽  
Author(s):  
Shaon Ghosh ◽  
Steven Bloemen ◽  
Gijs Nelemans ◽  
Paul J. Groot ◽  
Larry R. Price
Keyword(s):  
Gravitational Wave ◽  
Field Of View ◽  
Wide Field ◽  
Wide Field Of View

scholarly journals Processing GOTO data with the Rubin Observatory LSST Science Pipelines I: Production of coadded frames

2021 ◽  
Vol 38 ◽  
Author(s):  
J. R. Mullaney ◽  
L. Makrygianni ◽  
V. Dhillon ◽  
S. Littlefair ◽  
K. Ackley ◽  
...  
Keyword(s):  
Gravitational Wave ◽  
Time Domain ◽  
Wide Area ◽  
Wide Field ◽  
Process Data ◽  
Data Production ◽  
The Time Domain ◽  
Further Development ◽  
High Cadence

Abstract The past few decades have seen the burgeoning of wide-field, high-cadence surveys, the most formidable of which will be the Legacy Survey of Space and Time (LSST) to be conducted by the Vera C. Rubin Observatory. So new is the field of systematic time-domain survey astronomy; however, that major scientific insights will continue to be obtained using smaller, more flexible systems than the LSST. One such example is the Gravitational-wave Optical Transient Observer (GOTO) whose primary science objective is the optical follow-up of gravitational wave events. The amount and rate of data production by GOTO and other wide-area, high-cadence surveys presents a significant challenge to data processing pipelines which need to operate in near-real time to fully exploit the time domain. In this study, we adapt the Rubin Observatory LSST Science Pipelines to process GOTO data, thereby exploring the feasibility of using this ‘off-the-shelf’ pipeline to process data from other wide-area, high-cadence surveys. In this paper, we describe how we use the LSST Science Pipelines to process raw GOTO frames to ultimately produce calibrated coadded images and photometric source catalogues. After comparing the measured astrometry and photometry to those of matched sources from PanSTARRS DR1, we find that measured source positions are typically accurate to subpixel levels, and that measured L-band photometries are accurate to $\sim50$ mmag at $m_L\sim16$ and $\sim200$ mmag at $m_L\sim18$ . These values compare favourably to those obtained using GOTO’s primary, in-house pipeline, gotophoto, in spite of both pipelines having undergone further development and improvement beyond the implementations used in this study. Finally, we release a generic ‘obs package’ that others can build upon, should they wish to use the LSST Science Pipelines to process data from other facilities.

scholarly journals Extrasolar planet detections with gravitational microlensing

2007 ◽  
Vol 3 (S249) ◽  
pp. 25-30
Author(s):  
Shude Mao ◽  
Eamonn Kerins ◽  
Nicholas J. Rattenbury
Keyword(s):  
Light Curve ◽  
Real Time ◽  
Extrasolar Planets ◽  
Light Curves ◽  
Extrasolar Planet ◽  
Galactic Centre ◽  
Wide Field ◽  
High Magnification ◽  
Gravitational Microlensing

AbstractMicrolensing light curves due to single stars are symmetric and typically last for a month. So far about 4000 microlensing events have been discovered in real-time, the vast majority toward the Galactic centre. The presence of planets around the primary lenses induces deviations in the usual light curve which lasts from hours (for an Earth-mass [M⊕] planet) to days (for a Jupiter-mass [Mj] planet). Currently the survey teams, OGLE and MOA, discover and announce microlensing events in real-time, and follow-up teams (together with the survey teams) monitor selected events intensively (usually with high magnification) in order to identify anomalies caused by planets. So far four extrasolar planets have been discovered using the microlensing technique, with half a dozen new planet candidates identified in 2007 (yet to be published). Future possibilities include a network of wide-field 2m-class telescopes from the ground (which can combine survey and follow-up in the same setup) and a 1m-class survey telescope from space.

scholarly journals Classification of ASKAP VAST Radio Light Curves

2011 ◽  
Vol 7 (S285) ◽  
pp. 397-399 ◽  
Author(s):  
Umaa Rebbapragada ◽  
Kitty Lo ◽  
Kiri L. Wagstaff ◽  
Colorado Reed ◽  
Tara Murphy ◽  
...  
Keyword(s):  
Best Practices ◽  
Light Curve ◽  
Field Survey ◽  
Classification Performance ◽  
Light Curves ◽  
Classification Algorithms ◽  
Wide Field ◽  
Radio Transients ◽  
Instrument Sensitivity

AbstractThe VAST survey is a wide-field survey that observes with unprecedented instrument sensitivity (0.5 mJy or lower) and repeat cadence (a goal of 5 seconds) that will enable novel scientific discoveries related to known and unknown classes of radio transients and variables. Given the unprecedented observing characteristics of VAST, it is important to estimate source classification performance, and determine best practices prior to the launch of ASKAP's BETA in 2012. The goal of this study is to identify light-curve characterization and classification algorithms that are best suited for archival VAST light-curve classification. We perform our experiments on light-curve simulations of eight source types and achieve best-case performance of approximately 90% accuracy. We note that classification performance is most influenced by light-curve characterization rather than classifier algorithm.

scholarly journals Spectroscopy of candidate electromagnetic counterparts to gravitational wave sources

2016 ◽  
Vol 12 (S324) ◽  
pp. 283-286
Author(s):  
Iain A. Steele ◽  
Chris M. Copperwheat ◽  
Andrzej S. Piascik
Keyword(s):  
Black Hole ◽  
Gravitational Wave ◽  
Wide Field ◽  
Solar System Objects ◽  
Multi Wavelength ◽  
Binary Mergers ◽  
Black Hole Binary ◽  
Field Imaging ◽  
Wide Field Imaging

AbstractA programme of worldwide, multi-wavelength electromagnetic follow-up of sources detected by gravitational wave detectors is in place. Following the discovery of GW150914 and GW151226, wide field imaging of their sky localisations identified a number of candidate optical counterparts which were then spectrally classified. The majority of candidates were found to be supernovae at redshift ranges similar to the GW events and were thereby ruled out as a genuine counterpart. Other candidates ruled out include AGN and Solar System objects. Given the GW sources were black hole binary mergers, the lack of an identified electromagnetic counterpart is not surprising. However the observations show that it is possible to organise and execute a campaign that can eliminate the majority of potential counterparts. Finally we note the existence of a “classification gap” with a significant fraction of candidates going unclassified.

scholarly journals TheKepler Missionand Eclipsing Binaries

2006 ◽  
Vol 2 (S240) ◽  
pp. 236-243 ◽  
Author(s):  
David Koch ◽  
William Borucki ◽  
Gibor Basri ◽  
Timothy Brown ◽  
Douglas Caldwell ◽  
...  
Keyword(s):  
Eclipsing Binaries ◽  
Light Curves ◽  
Field Of View ◽  
Habitable Zone ◽  
Target List ◽  
Kepler Mission ◽  
Photometric Observations ◽  
Single Field ◽  
Verification Process

AbstractTheKepler Missionis a space-based photometric mission with a differential photometric precision of 14 ppm (atV= 12 for a 6.5 hour transit). It is designed to continuously observe a single field of view (FOV) of greater then 100 square degrees in the Cygnus-Lyra region for four or more years. The primary goal of the mission is to monitor more than one-hundred thousand stars for transits of Earth-size and smaller planets in the habitable zone of solar-like stars. In the process, many eclipsing binaries (EB) will also be detected and light curves produced. To enhance and optimize the mission results, the stellar characteristics for all the stars in theKeplerFOV withV< 16 will have been determined prior to launch. As part of the verification process, stars with transit candidates will have radial-velocity follow-up observations performed to determine the component masses and thereby separate eclipses caused by stellar companions from transits caused by planets. The result will be a rich database on EBs. The community will have access to the archive for further analysis, such as, for EB modeling of the high-precision light curves. A guest observer program is also planned to allow for photometric observations of objects not on the target list but within the FOV.

scholarly journals Ground-based photometry for 42 Kepler-field RR Lyrae stars

2013 ◽  
Vol 9 (S301) ◽  
pp. 427-428 ◽  
Author(s):  
Young-Beom Jeon ◽  
Chow-Choong Ngeow ◽  
James M. Nemec
Keyword(s):  
Light Curves ◽  
Astronomy Observatory ◽  
Color Information ◽  
Rr Lyrae Stars ◽  
Rr Lyrae ◽  
Photometric Observations ◽  
Data Points ◽  
Optical Astronomy ◽  
Lyrae Stars

AbstractFollow-up (U)BVRI photometric observations have been carried out for 42 RR Lyrae stars in the Kepler field. The new magnitude and color information will complement the available extensive high-precision Kepler photometry and recent spectroscopic results. The photometric observations were made with the following telescopes: 1-m and 41-cm telescopes of Lulin Observatory (Taiwan), 81-cm telescope of Tenagra Observatory (Arizona, USA), 1-m telescope at the Mt. Lemmon Optical Astronomy Observatory (LOAO, Arizona, USA), 1.8-m and 15-cm telescopes at the Bohyunsan Optical Astronomy Observatory (BOAO, Korea) and 61-cm telescope at the Sobaeksan Optical Astronomy Observatory (SOAO, Korea). The observations span from 2010 to 2013, with ~200 to ~600 data points per light curve. Preliminary results of the Korean observations were presented at the 5th KASC workshop in Hungary. In this work, we analyze all observations. These observations permit the construction of full light curves for these RR Lyrae stars and can be used to derive multi-filter Fourier parameters.

Evaluating the Utility of Mueller Matrix Imaging for Diffuse Material Classification

2020 ◽  
Author(s):  
Meredith Kupinski ◽  
Lisa Li
Keyword(s):  
Polarization State ◽  
Imaging Study ◽  
Optimization Method ◽  
Mueller Matrix ◽  
Classification Performance ◽  
Field Of View ◽  
Wide Field ◽  
Measured Intensity ◽  
Mueller Matrices ◽  
Wide Field Of View

Evaluating the utility of polarimetric imaging for material identification, as compared to conventional irradiance imaging, motivates this work. Images of diffuse objects captured with a wide field of view Mueller matrix polarimeter are used to demonstrate a classification and measurement optimization method. This imaging study is designed to test polarimetric utility in discriminating white fabric from white wood. The material color is constrained to be similar so that classification from only total radiance imaging is difficult, i.e., metamerism. A statistical divergence between two distributions of measured intensity is used to optimize the Polarization State Generator (PSG) and the Polarization State Analyzer (PSA) given two classes of Mueller matrices. The classification performance as a function of number of polarimetric measurements is computed. This work demonstrates that two polarimetric measurements of white fabric and white wood offer nearly perfect classification. The utility and design of partial Mueller imaging is supported by this optimization of PSG/PSA states and number of measurements.

DETECTING GRAVITATIONAL WAVES AND THEIR ELECTROMAGNETIC COUNTERPARTS

2011 ◽  
Vol 20 (10) ◽  
pp. 1883-1890
Author(s):  
LINQING WEN
Keyword(s):  
Gravitational Wave ◽  
Gravitational Waves ◽  
Graphics Processing Units ◽  
Hardware Acceleration ◽  
Detection Methods ◽  
Wide Field ◽  
Theory Of Relativity ◽  
Detection And Identification ◽  
Graphics Processing

In the next decade, we expect a first detection of gravitational waves predicted by Einstein's general theory of relativity. A detection of their electromagnetic counterparts will significantly contribute to our confidence in a first time detection and identification of the source. We discuss the challenges in using gravitational-wave events as triggers for prompt follow-up electromagnetic observations. We demonstrate that wide-field cameras are desirable for follow-up observations of gravitational wave sources and that a larger gravitational wave detector network, e.g. adding AIGO detector in Australia, can significantly help pinpoint the direction of gravitational wave sources. We also argue that low-latency real-time detection methods and hardware acceleration using graphics processing units will help generate prompt gravitational-wave triggers within the time frames allowed for electromagnetic follow-ups in the era of advanced detectors.

scholarly journals NEOPAT: Near-Earth Object PATrol program

2001 ◽  
Vol 183 ◽  
pp. 240-244
Author(s):  
Hong-Kyu Moon ◽  
Moo-Young Chun ◽  
Yong-Ik Byun ◽  
Wonyong Han ◽  
Seung-Lee Kim ◽  
...  
Keyword(s):  
High Efficiency ◽  
Wide Field ◽  
Main Belt ◽  
Earth Object ◽  
Data Pipeline ◽  
Wide Field Of View ◽  
Survey System ◽  
Robotic Telescopes ◽  
Astronomical Research

AbstractIn 2000, Korea Astronomy Observatory launched the Near-Earth Object Patrol (NEOPAT) program. NEOPAT has conducted follow-up observations of NEOCP (NEO Confirmation Page) objects and discovered 52 new main-belt asteroids during the observation runs. We initiated collaboration with the Yonsei Survey Telescopes for Astronomical Research (YSTAR) team for NEO search. Wide-field of view, fast read-out time, and fully autonomous data pipeline will enable us to detect and track NEOs with a high efficiency. Scheduled to begin active operations in mid-2001, our survey system is going to be the first network of robotic telescopes for NEO search with automatic access to both hemispheres.

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