Search results for " Photometry"

showing 10 items of 44 documents

BVRI photometry of high-mass X-ray binaries

2015

We present photometric observations of the field around the optical counterparts of high-mass X-ray binaries. Our aim is to study the long-term photometric variability in correlation with their X-ray activity and derive a set of secondary standard stars that can be used for time series analysis. We find that the donors in Be/X-ray binaries exhibit larger amplitude changes in the magnitudes and colours than those hosting a supergiant companion. The amplitude of variability increases with wavelength in Be/X-ray binaries and remains fairly constant in supergiant systems. When time scales of years are considered, a good correlation between the X-ray and optical variability is observed. The X-ra…

Astrophysics and AstronomyX-ray binary starsAstrophysics::High Energy Astrophysical PhenomenaPhysicsOptical astronomyPhotometryobservational astronomyStellar AstronomyAstrophysics::Solar and Stellar AstrophysicsAstrophysics::Earth and Planetary AstrophysicsWide-band photometryX ray binary starsNatural SciencesAstrophysics::Galaxy AstrophysicsInfrared photometryWide band photometry
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BALDONE 1.2M TELESCOPE PLATE ARCHIVE - HIDDEN RESERVES OF THE FON PROJECT

2018

The plate archive of the 1.2 m Baldone telescope (Latvia) has approximately 780 and 4660 astronegatives exposed in 1967-1993 in the U (ZU21 + UG1 filter plates) and V (A600N + ZS17 filter films) closed to Johnson system U and V passbands. Digitization of astronegatives is carried out using the Epson Expression 10000XL scanner, the scanning mode is 1200 or 2400 dpi, each field covers 19 square degrees of sky.  The plates and films are scanned at the Baldone Observatory, processing of digitized scans is carried out by the observers in Baldone, at the Research Institute "Mykolaiv Astronomical Observatory" and at the Main Astronomical Observatory of the National Academy of Sciences of Ukraine. …

Brightnesseducation.field_of_studylcsh:AstronomyPopulationAstronomyAstrometrylaw.inventionlcsh:QB1-991Photometry (optics)TelescopeStarsObservatorylawscanning; processing of digitized plates; FON project; astrometry; photometry; data analysiseducationGeologyOpen clusterOdessa Astronomical Publications
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Near-IR Galaxy Counts and Evolution from the Wide-Field ALHAMBRA survey

2009

arxiv:0902.2403v1

Cosmology and Nongalactic Astrophysics (astro-ph.CO)LogarithmFOS: Physical sciencesAstrophysicsSurveysSquare (algebra)LuminosityPhotometry (optics)high-redshift [Galaxies]galaxies [Infrared]observations [Cosmology]Physicsphotometry [Galaxies]Cosmology: observationsGalaxies: high-redshiftGalaxies: evolutionAstronomy and AstrophysicsGalaxies: photometryH bandInfrared: galaxiesevolution [Galaxies]J bandRedshiftGalaxySpace and Planetary ScienceAstrophysics - Cosmology and Nongalactic Astrophysics
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SHARDS: A global view of the star formation activity at z~0.84 and z~1.23

2015

et al.

Galaxies: generalAstrofísicaStellar massFOS: Physical sciencesAstrophysicsAstrophysics::Cosmology and Extragalactic Astrophysicsstar formation [Galaxies]Luminosityhigh-redshift [Galaxies]emission lines [Quasars]Stellar evolutionAstrophysics::Galaxy AstrophysicsCosmic dustPhysicsQuasars: emission linesGalaxies: star formationStar formationphotometry [Galaxies]Galaxies: high-redshiftGalaxies: evolutiongeneral [Galaxies]Astronomy and AstrophysicsQuasarGalaxies: photometryevolution [Galaxies]Astrophysics - Astrophysics of GalaxiesRedshiftGalaxyAstronomíaSpace and Planetary ScienceAstrophysics of Galaxies (astro-ph.GA)
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Evolution of Balmer jump selected galaxies in the ALHAMBRA survey

2016

Extragalactic astronomy.-- et al.

Galaxies: generalAstrophysics::High Energy Astrophysical PhenomenaFOS: Physical sciencesAstrophysicsAstrophysics::Cosmology and Extragalactic Astrophysics01 natural sciencesevolution [Galaxy]high-redshift [Galaxies]Galactic haloBalmer jump0103 physical sciencesGalaxy formation and evolutionAstrophysics::Solar and Stellar Astrophysicshalo [Galaxy]010303 astronomy & astrophysicsComputingMilieux_MISCELLANEOUSAstrophysics::Galaxy Astrophysics[PHYS]Physics [physics]PhysicsGalaxy: evolution010308 nuclear & particles physicsphotometry [Galaxies]Astrophysics::Instrumentation and Methods for AstrophysicsGalaxies: high-redshiftGalaxies: evolutiongeneral [Galaxies]Astronomy and AstrophysicsGalaxies: photometryevolution [Galaxies]Astrophysics - Astrophysics of GalaxiesGalaxyPhysics::History of PhysicsGalaxy: haloSpace and Planetary ScienceAstrophysics of Galaxies (astro-ph.GA)[PHYS.ASTR]Physics [physics]/Astrophysics [astro-ph]Astronomy & Astrophysics
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A simple method for the photometric characterization of organic light-emitting diodes

2022

A simple method for the photometric characterization of organic light-emitting diodes (OLEDs) is reported. It is based on the indirect measurement of the total emitted optical power by using a calibrated photodiode and the optical emission spectrum and space emission diagram of the OLED. From this and by measuring the current–voltage characteristic of the OLED all the relevant radiometric and photometric quantities can be extracted, including the external quantum efficiency. The usual method to collect all photons emitted by a LED source in the half space uses an integrating sphere with the LED source placed at the entrance hole and a photodiode (PD) placed at an exit hole at some point on …

HistoryPolymers and PlasticsMaterials ChemistryOrganic light-emitting diodes (OLEDs) External quantum efficiency Radiometry Photometry AlQ3Business and International ManagementElectrical and Electronic EngineeringCondensed Matter PhysicsSettore ING-INF/01 - ElettronicaIndustrial and Manufacturing EngineeringElectronic Optical and Magnetic MaterialsSolid-State Electronics
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BVI photometry in NGC 6611

2007

VizieR online Data Catalogue associated with article published in journal Astronomy & Astrophysics with title 'Correlation between the spatial distribution of circumstellar disks and massive stars in the open cluster NGC 6611. Compiled catalog and cluster parameters.' (bibcode: 2007A&A...462..245G)

Open star clustersPhotometryAstrophysics::Instrumentation and Methods for AstrophysicsAstrophysics::Solar and Stellar AstrophysicsAstrophysics::Earth and Planetary AstrophysicsAstrophysics::Cosmology and Extragalactic AstrophysicsWide-band photometryAstrophysics::Galaxy AstrophysicsInfrared photometryOptical astronomy
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BVI & JHK photometry of NGC 3960

2004

VizieR online Data Catalogue associated with article published in journal Astronomy & Astrophysics with title 'Parameter properties and stellar population of the old open cluster NGC 3960.' (bibcode: 2004A&A...417..945P)

Open star clustersPhotometryCCD photometryWide-band photometryInfrared photometryOptical astronomy
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Mapping accretion variability in NGC 2264

2014

Our study aims at characterizing the accretion properties of several hundred members of the star-forming region NGC 2264 (3Myr). We performed a deep u,g,r,i mapping of the cluster with CFHT/MegaCam, and monitored the simultaneous u+r variability of its members over a baseline of two weeks. Stellar parameters are determined homogeneously for about 750 monitored young objects, 40% of which are accreting T Tauri stars. Accretion properties and accretion variability are investigated and characterized from UV excess measurements. Non-accreting members of the cluster define the reference UV emission level over which flux excess is detected and measured. Cone search capability for table J/A+A/570/…

Open star clustersPhotometryobservational astronomyAccretionAstrophysics and AstronomyPhysicsCCD photometryAstrophysical ProcessesNatural SciencesSloan photometrystellar astronomyOptical astronomy
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X-ray sources in NGC 752

2008

While observational evidence shows that most of the decline in a star's X-ray activity occurs between the age of the Hyades (~8x10^8yr) and that of the Sun, very little is known about the evolution of stellar activity between these ages. To gain information on the typical level of coronal activity at a star's intermediate age, we studied the X-ray emission from stars in the 1.9Gyr old open cluster NGC 752. We analysed a ~140ks Chandraobservation of NGC 752 and a ~50ks XMM-Newtonobservation of the same cluster. We detected 262 X-ray sources in the Chandra data and 145 sources in the XMM-Newton observation. Around 90% of the catalogued cluster members within Chandra's field-of-view are detect…

Open star clustersPhotometryobservational astronomyAstrophysics and AstronomyX ray sourcesStellar AstronomyPhysicsX-ray sourcesNatural SciencescosmologyInfrared photometry
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