scholarly journals YSTAR: Yonsei Survey Telescopes for Astronomical Research

2001 ◽  
Vol 183 ◽  
pp. 83-87
Author(s):  
Yong-Ik Byun ◽  
Won-Yong Han ◽  
Yong-Woo Kang ◽  
Moo-Young Chun ◽  
Sung-Yeol Yu ◽  
...  
Keyword(s):  
South Africa ◽  
Variable Stars ◽  
Primary Objective ◽  
Wide Field ◽  
Target Acquisition ◽  
Data Set ◽  
Field Surveys ◽  
Sky Survey ◽  
Two Factors ◽  
Astronomical Research

AbstractThe YSTAR program is a general sky survey looking for variability. The main equipments are three 0.5-m telescopes. These telescopes have fast F/2 optics covering nearly 3.5 square degree field onto a 2K CCD. They also have very fast slew capability, which exceeds 10 degrees per second. These two factors make them most suitable for rapid target acquisition and wide-field surveys of various kinds. Our primary objective is to identify and monitor variable stars down to 18th R-magnitude, and our observing mode allows the same data set to be also useful in identifying asteroids. Our first telescope has just begun regular automated operation, and the second telescope will be installed in South Africa within this year to provide coverage of the southern sky.

scholarly journals SuperWASP variable stars: classifying light curves using citizen science

2021 ◽  
Vol 502 (1) ◽  
pp. 1299-1311
Author(s):  
Heidi B Thiemann ◽  
Andrew J Norton ◽  
Hugh J Dickinson ◽  
Adam McMaster ◽  
Ulrich C Kolb
Keyword(s):  
Variable Stars ◽  
Eclipsing Binaries ◽  
Light Curves ◽  
Data Set ◽  
Resultant Data ◽  
Sky Survey ◽  
Short Period ◽  
Contact Binaries ◽  
Analysis Of Results

ABSTRACT We present the first analysis of results from the SuperWASP variable stars Zooniverse project, which is aiming to classify 1.6 million phase-folded light curves of candidate stellar variables observed by the SuperWASP all sky survey with periods detected in the SuperWASP periodicity catalogue. The resultant data set currently contains >1 million classifications corresponding to >500 000 object–period combinations, provided by citizen–scientist volunteers. Volunteer-classified light curves have ∼89 per cent accuracy for detached and semidetached eclipsing binaries, but only ∼9 per cent accuracy for rotationally modulated variables, based on known objects. We demonstrate that this Zooniverse project will be valuable for both population studies of individual variable types and the identification of stellar variables for follow-up. We present preliminary findings on various unique and extreme variables in this analysis, including long-period contact binaries and binaries near the short-period cut-off, and we identify 301 previously unknown binaries and pulsators. We are now in the process of developing a web portal to enable other researchers to access the outputs of the SuperWASP variable stars project.

Infrared Surveys Planned for ASTRO-F

2005 ◽  
Vol 216 ◽  
pp. 347-352
Author(s):  
Hiroshi Shibai
Keyword(s):  
Far Infrared ◽  
Wide Field ◽  
Wavelength Band ◽  
Mid Infrared ◽  
Field Surveys ◽  
Infrared Wavelength ◽  
Sky Surveys ◽  
Sky Survey ◽  
Infrared Surveys ◽  
Higher Sensitivity

The next survey mission, ASTRO-F, is scheduled for launch in 2005. This is the first Japanese satellite dedicated to infrared astronomy. The primary purpose of this project is to investigate the birth and evolution of galaxies in the early universe through deep, wide-field surveys at wavelengths ranging from 2 to 200 microns. In the far-infrared wavelength band, ASTRO-F will conduct an all-sky survey like the IRAS survey with several tens of times higher sensitivity and several times better spatial resolution. In the near- and mid-infrared, wide area sky-surveys will be conducted over pre-selected portions of the sky in 13 bands ranging from 2-200microns. In addition to these photometric surveys, low-resolution spectroscopic capabilities are available for all wavelength bands. The ASTRO-F mission will produce a fundamental database for the next generation of advanced observatories, for example Herschel, and JWST, and will complement the SIRTF mission by virtue of its wide sky coverage.

scholarly journals Search for radio emission from the exoplanets Qatar-1b and WASP-80b near 150 MHz using the giant metrewave radio telescope

2020 ◽  
Vol 500 (1) ◽  
pp. 211-214
Author(s):  
D A Green ◽  
N Madhusudhan
Keyword(s):  
Radio Emission ◽  
Radio Source ◽  
Radio Telescope ◽  
Magnetic Moments ◽  
Wide Field ◽  
Extragalactic Radio Source ◽  
Field Surveys ◽  
Very Large Array ◽  
Sky Survey ◽  
Cross Match

ABSTRACT We present radio observations made towards the exoplanets Qatar-1b and WASP-80b near 150 MHz with the Giant Meterwave Radio Telescope (GMRT). These targets are relatively nearby irradiated giant exoplanets, a hot Jupiter and a hot Saturn, with sizes comparable to Jupiter but different masses and lower densities. Both the targets are expected to host extended H/He envelopes like Jupiter, with comparable or larger magnetic moments. No radio emission was detected from these exoplanets, with 3σ limits of 5.9 and 5.2 mJy for Qatar-1b and WASP-80b, respectively, from these targeted observations. These are considerably deeper limits than those available for exoplanets from wide-field surveys at similar frequencies. We also present archival Very Large Array (VLA) observations of a previously reported radio source close to 61 Vir (which has three exoplanets). The VLA observations resolve the source, which we identify as an extragalactic radio source, i.e. a chance association with 61 Vir. Additionally, we cross-match a recent exoplanet catalogue with the TIFR GMRT Sky Survey ADR1 radio catalogue, but do not find any convincing associations.

scholarly journals The Potential of the Wide Field Camera on ROSAT for Investigations of the XUV Background

1990 ◽  
Vol 139 ◽  
pp. 463-464
Author(s):  
Alan W. Harris ◽  
Helen J. Walker ◽  
Timothy J. Sumner
Keyword(s):  
Grazing Incidence ◽  
Space Science ◽  
Primary Objective ◽  
Wide Field ◽  
Science Laboratory ◽  
Joint Project ◽  
X Ray ◽  
Sky Survey ◽  
Space Science Laboratory

The ROSAT X-ray astronomy satellite, due to be launched in early 1990, will carry two separate and complementary grazing-incidence telescopes with co-aligned axes. The German X-ray telescope (XRT) will cover the soft X-ray region in the range 0.15–2 keV (6–80 Å), while the U.K. XUV Wide Field Camera (WFC) will extend coverage to beyond 200 Å. The WFC is a joint project of Leicester and Birmingham Universities, the Mullard Space Science Laboratory, and the authors' institutes. The primary objective of ROSAT is to perform an all-sky survey over a period of six months. This will be followed by a guest-observer, “pointed” phase. We briefly discuss the sensitivity of the WFC to the soft X-ray/XUV background (SXRB) and the problems and techniques associated with distinguishing the astronomical background from other sources of background.

Infrared Wide-Field Surveys

1994 ◽  
Vol 161 ◽  
pp. 13-16
Author(s):  
N. Epchtein
Keyword(s):  
Near Infrared ◽  
Wide Field ◽  
Field Surveys ◽  
Sky Surveys ◽  
The Past ◽  
Infrared Spectral Range ◽  
Sky Survey ◽  
Array Technology ◽  
Infrared Spectral ◽  
Infrared Array

Optical wide-field sky surveys have long been basic tools of astronomical investigations. Their extension to the near infrared spectral range, unattainable with photographic techniques, is now possible thanks to the considerable improvements in infrared array technology that have been achieved in the past few years. The astronomical motivations for all-sky 2 μm surveys are summarized, and a brief technical description of the on-going projects, in particular DENIS (Deep Near Infrared Southern Sky Survey) that will be carried out at the European Southern Observatory in 1994–97, is presented.

scholarly journals The ASTRO-F (IRIS) Mission

2001 ◽  
Vol 204 ◽  
pp. 455-466 ◽  
Author(s):  
Hiroshi Shibai
Keyword(s):  
Spatial Resolution ◽  
Far Infrared ◽  
Wide Field ◽  
Natural Background ◽  
Mid Infrared ◽  
Field Surveys ◽  
Infrared Wavelength ◽  
Sky Survey ◽  
Aperture Diffraction ◽  
Higher Sensitivity

ASTRO-F (IRIS) is the first Japanese satellite dedicated to infrared astronomy. The primary purpose of this project is to investigate the birth and evolution of galaxies in the early universe through deep, wide-field surveys at wavelengths ranging from 2 to 200 microns. The spatial resolution and the point source sensitivity are nearly the same as those of the aperture diffraction limit and the natural background and/or confusion limit, respectively. In the far-infrared wavelength band, ASTRO-F will conduct an all-sky survey like the IRAS survey with several tens of times higher sensitivity and several times better spatial resolution. In the near- and mid-infrared, wide area sky-surveys will be conducted over pre-selected portions of the sky. In addition to these photometric surveys, low-resolution spectroscopic capabilities are available for all wavelength bands. The ASTRO-F mission will produce a fundamental database for the next generation of advanced observatories, for example FIRST, and NGST, and will complement the SIRTF mission by virtue of its wide sky coverage. The launch by an M-V rocket is scheduled for February or March of 2004.

scholarly journals Revised and Updated Catalogue of the First Byurakan Survey Late-Type Stars. 2nd Edition

2018 ◽  
pp. 262-267
Author(s):  
K. S. Gigoyan ◽  
A. M. Mickaelian ◽  
G. R. Kostandyan
Keyword(s):  
Variable Stars ◽  
Sloan Digital Sky Survey ◽  
Asymptotic Giant Branch ◽  
Wide Field ◽  
Late Type ◽  
Byurakan Survey ◽  
First Byurakan Survey ◽  
Sky Survey ◽  
Search And Selection ◽  
Low Dispersion

Eighteen lists of late-type stars (LTSs) have been published between 1990 and 2016. These LTSs have been found in the low-dispersion spectroscopic plates of the First Byurakan Survey (FBS). The systematic search and selection was carried out on a surface _16000 deg2 on almost the whole area of the FBS. As a result, \Revised And Updated Catalogue Of The First Byurakan Survey Of Late-Type Stars" was generated (LTSs, _rst version). Since 2007, all FBS low-resolution spectral plates are digitized, and Digitized First Byurakan Survey (DFBS) database and second catalog of objects has been assembled. All DFBS spectral plates are analysed with the help of standard image analysis softwares (FITSView and SAO Image ds9) and numerous of comparatively faint LTSs were discovered. We present the 2nd version of the FBS catalogue of LTSs with new data. We have made cross-correlation with the Digitized First Byurakan Survey (DFBS), the United State Naval Observatory-B1.0 Catalogue, the Two Micron All-Sky Survey (2MASS), the Wide-Field Infrared Survey Explorer (new version-ALLWISE) catalogue, the Infrared Astronomical Satellite Point Source Catalogue/Faint Source Catalogue, the AKARI catalogue, the ROSAT Bright Source Catalogue/Faint Source Catalogue, the General Catalogue of Variable Stars, Sloan Digital Sky Survey (SDSS) photometric catalogue. We have added updated IMBAD data for the objects. For numerous of the new detected objects we present accurate Digitized Sky Survey 2 positions, approximate spectral subtypes refined from the DFBS low-dispersion spectra, luminosity classes estimated from 2MASS colours, and available proper motions for 1471 FBS LTSs. 2nd Version of the Revised and Updated Catalogue lists a large number of completely new objects, which promise to extend very significantly the census of M giants, faint N-type Asymptotic Giant Branch (AGB) carbon stars, CH {type carbon giants at high Galactic latitudes, also M dwarfs in the vicinity of the Sun up to 16.0-17.0 mag. in visual. We present also some important data from the Gaia DR2 data base for FBS LTSs. Some supplementary spectra obtained with the Byurakan Observatory 2.6 m telescope and LAMOST telescope are shown.

scholarly journals From Asteroids to Space Debris

2015 ◽  
Vol 10 (S318) ◽  
pp. 324-326 ◽  
Author(s):  
Zouhair Benkhaldoun ◽  
Hong-Kyu Moon ◽  
Ahmed Daassou ◽  
Jang-Hyun Park ◽  
Mohamed Lazrek
Keyword(s):  
Space Debris ◽  
Primary Objective ◽  
Wide Field ◽  
National Space ◽  
The Past ◽  
Sky Survey ◽  
Transient Events ◽  
Field Imaging ◽  
Wide Field Imaging

AbstractSince 2011, Oukaimeden Observatory (OUCA) has become one of the active NEO search facilities in the word. Its discovery statistics shows that the MOSS (Morocco Oukaimeden Sky Survey) project received credits for more than 2,145 new designations, including 3 NEOs and 4 comets. Its excellent astro-climactic characteristics are partly behind the success. The average number of observable nights is around 280 nights per year, while median seeing is 0.8-0.9 arcsec. We completed construction of a new telescope at the site in March 2015. It is Optical Wide-field Patrol (OWL) facility designed and built by Korea Space Science Institute (KASI). The primary objective of this facility is to monitor national space assets of Korea; either wide-field imaging- or fast data acquisition- capabilities enable the 0.5m telescope to conduct observation programs to catalog and follow-up various transient events in the night sky. We present the seeing condition, the OWL system and preliminary results obtained at OWL@Oukaimeden during the past several months.

scholarly journals Testing the evolution of correlations between supermassive black holes and their host galaxies using eight strongly lensed quasars

2020 ◽  
Vol 501 (1) ◽  
pp. 269-280
Author(s):  
Xuheng Ding ◽  
Tommaso Treu ◽  
Simon Birrer ◽  
Adriano Agnello ◽  
Dominique Sluse ◽  
...  
Keyword(s):  
Black Holes ◽  
Hubble Space Telescope ◽  
High Redshift ◽  
Galactic Nuclei ◽  
Host Galaxy ◽  
Wide Field ◽  
Host Galaxies ◽  
Field Surveys ◽  
Instrumental Resolution ◽  
The Moment

ABSTRACT One of the main challenges in using high-redshift active galactic nuclei (AGNs) to study the correlations between the mass of a supermassive black hole ($\mathcal {M}_{\rm BH}$) and the properties of its active host galaxy is instrumental resolution. Strong lensing magnification effectively increases instrumental resolution and thus helps to address this challenge. In this work, we study eight strongly lensed AGNs with deep Hubble Space Telescope imaging, using the lens modelling code lenstronomy to reconstruct the image of the source. Using the reconstructed brightness of the host galaxy, we infer the host galaxy stellar mass based on stellar population models. $\mathcal {M}_{\rm BH}$ are estimated from broad emission lines using standard methods. Our results are in good agreement with recent work based on non-lensed AGNs, demonstrating the potential of using strongly lensed AGNs to extend the study of the correlations to higher redshifts. At the moment, the sample size of lensed AGNs is small and thus they provide mostly a consistency check on systematic errors related to resolution for non-lensed AGNs. However, the number of known lensed AGNs is expected to increase dramatically in the next few years, through dedicated searches in ground- and space-based wide-field surveys, and they may become a key diagnostic of black holes and galaxy co-evolution.

scholarly journals The Conditions for after Work: Financialization and Informalization in Posttransition South Africa

PMLA ◽  
2012 ◽  
Vol 127 (4) ◽  
pp. 782-799 ◽  
Author(s):  
Anne-Maria Makhulu
Keyword(s):  
South Africa ◽  
Informal Settlements ◽  
Global South ◽  
First Century ◽  
Informal Employment ◽  
Shop Floor ◽  
Two Factors ◽  
Informal Economies ◽  
Forms Of Life ◽  
Modes Of Life

This essay situates the problem of twenty-first-century work in the global South—specifically, in South Africa—to challenge northern theories of the crisis of work. Addressing the break between Fordism and post-Fordism peculiar to the postcolonial context, it argues that new regimes of work should be understood in relation both to longer histories of colonial resistance to proletarianization (to the racisms of the shop floor) and to colonial Fordisms, as well as to the way these two factors inform the current expansion of informal employment. What practices and forms of life emerge from the precarity of informal economies and informal settlements? How are precarious modes of life connected to and informed by the steady dematerialization of the economy through financialization?

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