The Absolute Flux Calibration of Strömgren [CLC][ITAL]uvby[/ITAL][/CLC] Photometry

1998 ◽  
Vol 116 (1) ◽  
pp. 482-485 ◽  
Author(s):  
R. O. Gray
Keyword(s):  
Absolute Flux ◽  
The Absolute ◽  
Flux Calibration

The Absolute Flux Calibration of the UVBY Photometric System

1996 ◽  
Vol 108 ◽  
pp. 90 ◽  
Author(s):  
Juan Fabregat ◽  
Pablo Reig
Keyword(s):  
Photometric System ◽  
Absolute Flux ◽  
The Absolute ◽  
Flux Calibration

scholarly journals Characterisation of the MALT90 Survey and the Mopra Telescope at 90 GHz

2013 ◽  
Vol 30 ◽  
Author(s):  
J. B. Foster ◽  
J. M. Rathborne ◽  
P. Sanhueza ◽  
C. Claysmith ◽  
J. S. Whitaker ◽  
...  
Keyword(s):  
Time Of Day ◽  
Repeated Observations ◽  
Absolute Flux ◽  
The Absolute ◽  
Flux Calibration

AbstractWe characterise the Millimetre Astronomy Legacy Team 90 GHz Survey (MALT90) and the Mopra telescope at 90 GHz. We combine repeated position-switched observations of the source G300.968+01.145 with a map of the same source in order to estimate the pointing reliability of the position-switched observations and, by extension, the MALT90 survey; we estimate our pointing uncertainty to be 8 arcsec. We model the two strongest sources of systematic gain variability as functions of elevation and time-of-day and quantify the remaining absolute flux uncertainty. Corrections based on these two variables reduce the scatter in repeated observations from 12%–25% down to 10%–17%. We find no evidence for intrinsic source variability in G300.968+01.145. For certain applications, the corrections described herein will be integral for improving the absolute flux calibration of MALT90 maps and other observations using the Mopra telescope at 90 GHz.

scholarly journals Optical Spectrophotometry of Nova PW Vulpeculae

1990 ◽  
Vol 122 ◽  
pp. 159-160 ◽  
Author(s):  
J. Mikołajewska ◽  
M. Mikołajewski
Keyword(s):  
Spectral Sensitivity ◽  
Spectral Range ◽  
Atmospheric Extinction ◽  
Absolute Flux ◽  
Classical Nova ◽  
The Absolute ◽  
Cassegrain Telescope ◽  
Optical Spectrophotometry ◽  
Low Dispersion ◽  
Flux Calibration

PW Vul (Nowa Vul 1984 #1) was a slow classical nova which began its outburst in July 1984 and reached optical maximum in the first week of August 1984. Eight low dispersion spectra (160 A/mm) in the blue spectral range (λλ3400-5100 A) were secured between October 1984 and July 1985, with the CCS spectrograph equipped with 3.5 arcsec aperture image slicer and mounted on 90 cm Schmidt-Cassegrain telescope at Toruń Observatory. Kodak IIa-O plates were used. In addition two moderate dispersion (40 A/mm) spectra in the Hγ-Hβ range were obtained on 28 October and 3 November 1984, using the same instrumentation. Standard stars were observed on each night to remove the influence of spectral sensitivity of the photographic emulssion and atmospheric extinction. The calibration of the absolute flux scale was performed by comparing synthetic B magnitudes calculated from our spectra with published B photometry of PW Vul (Voloshina 1985, Noskova et al. 1985, Kolotilov and Noskova 1986). The accuracy of the flux calibration is ±0.1 mag.

scholarly journals The Gaia spectrophotometric standard stars survey - IV. Results of the absolute photometry campaign.

2020 ◽  
Author(s):  
G Altavilla ◽  
S Marinoni ◽  
E Pancino ◽  
S Galleti ◽  
M Bellazzini ◽  
...  
Keyword(s):  
Photometric Calibration ◽  
Absolute Flux ◽  
Current Limit ◽  
Calibration Accuracy ◽  
The Absolute ◽  
Sky Conditions ◽  
Stars Survey ◽  
Flux Calibration

Abstract We present Johnson-Kron-Cousins BVRI photometry of 228 candidate spectrophotometric standard stars for the external (absolute) flux calibration of Gaia data. The data were gathered as part of a ten-year observing campaign with the goal of building the external grid of flux standards for Gaia and we obtained absolute photometry, relative photometry for constancy monitoring, and spectrophotometry. Preliminary releases of the flux tables were used to calibrate the first two Gaia releases. This paper focuses on the imaging frames observed in good sky conditions (about 9100). The photometry will be used to validate the ground-based flux tables of the Gaia spectrophotometric standard stars and to correct the spectra obtained in non-perfectly photometric observing conditions for small zeropoint variations. The absolute photometry presented here is tied to the Landolt standard stars system to ≃1 per cent or better, depending on the photometric band. Extensive comparisons with various literature sources show an overall ≃1 per cent agreement, which appears to be the current limit in the accuracy of flux calibrations across various samples and techniques in the literature. The Gaia photometric precision is presently of the order of 0.1 per cent or better, thus various ideas for the improvement of photometric calibration accuracy are discussed.

New method for estimating the absolute flux and energy spectrum of solar cosmic rays based on neutron-monitor data

JETP Letters ◽  
2008 ◽  
Vol 88 (7) ◽  
pp. 411-413 ◽  
Author(s):  
G. F. Krymsky ◽  
V. G. Grigor’ev ◽  
S. A. Starodubtsev
Keyword(s):  
Energy Spectrum ◽  
Cosmic Rays ◽  
Neutron Monitor ◽  
New Method ◽  
Solar Cosmic Rays ◽  
Absolute Flux ◽  
The Absolute ◽  
Neutron Monitor Data ◽  
Monitor Data

scholarly journals The Status of the Absolute Calibration of Stellar Fluxes Between 912 and 1200 Å

1985 ◽  
Vol 111 ◽  
pp. 479-483
Author(s):  
R. S. Polidan ◽  
J. B. Holberg
Keyword(s):  
Planetary Nebula ◽  
White Dwarfs ◽  
Main Sequence ◽  
Absolute Calibration ◽  
Energy Distributions ◽  
B Stars ◽  
The Status ◽  
The Absolute ◽  
Flux Calibration

Recent results have shed new light on the status of the calibration of absolute stellar fluxes between 912 and 1200 Å. Observations of hot white dwarfs, subdwarfs and planetary nebula nuclei with the Voyager ultraviolet spectrometers provide evidence that the current calibration agrees very well with extrapolations of IUE energy distributions shortwards of 1200 Å. Voyager observations of main sequence B-stars used as flux calibration sources have revealed that many are variable in brightness in the 912–1200 Å region. We conclude there is no current observational motivation for any revision of the 912 to 1200 Å calibration described by Holberg et al. (1982).

scholarly journals The UV Spectrum of W Cep.

1980 ◽  
Vol 88 ◽  
pp. 549-553
Author(s):  
R. Faraggiana
Keyword(s):  
Uv Spectrum ◽  
Absolute Flux ◽  
The Absolute

IUE spectra of VV Cep have been obtained in 1978 and 1979 during the chromospheric phase of the eclipse. The profiles of the Mg II resonance lines differ from one another and this peculiarity, common to other M type supergiants, is examined. The value of Mv derived from the extension of the Wilson and Bappu relation to Mg II lines is compared with other determinations. The variation of the absolute flux in the 1200-2000 Å range is presented.

scholarly journals ABSOLUTE FLUX CALIBRATION OF THE IRAC INSTRUMENT ON THESPITZER SPACE TELESCOPEUSINGHUBBLE SPACE TELESCOPEFLUX STANDARDS

2011 ◽  
Vol 141 (5) ◽  
pp. 173 ◽  
Author(s):  
R. C. Bohlin ◽  
K. D. Gordon ◽  
G. H. Rieke ◽  
D. Ardila ◽  
S. Carey ◽  
...  
Keyword(s):  
Absolute Flux ◽  
Flux Calibration

26.3-MHz radio source survey. I - The absolute flux scale

1975 ◽  
Vol 80 ◽  
pp. 83 ◽  
Author(s):  
M. R. Viner
Keyword(s):  
Radio Source ◽  
Absolute Flux ◽  
The Absolute

scholarly journals Diagnosing the Surface Layer Parameters for Dispersion Models within the Meteorological-to-Dispersion Modeling Interface

2010 ◽  
Vol 49 (2) ◽  
pp. 221-233 ◽  
Author(s):  
M. Sofiev ◽  
E. Genikhovich ◽  
P. Keronen ◽  
T. Vesala
Keyword(s):  
Surface Layer ◽  
Weather Forecasting ◽  
Dispersion Model ◽  
Temporal Correlation ◽  
Complex Surface ◽  
Dispersion Modeling ◽  
Limited Area ◽  
Dispersion Models ◽  
Absolute Flux ◽  
The Absolute

Abstract The problem of providing dispersion models with meteorological information from general atmospheric models used, for example, for weather forecasting is considered. As part of a generalized meteorological-to-dispersion model interface, a noniterative scheme diagnosing the surface layer characteristics from wind, temperature, and humidity profiles was developed. The scheme verification included long-term comparison with data of meteorological masts at Cabauw, the Netherlands, and Hyytiälä, Finland. The algorithm compatibility and consistency with the High-Resolution Limited-Area Model (HIRLAM) was also checked, as this model is routinely used as a meteorological driver for the Air Quality and Emergency Modeling System (SILAM). The comparison with Cabauw mast data showed a good quantitative agreement between observed and diagnosed heat and momentum fluxes: the temporal correlation coefficient was ∼0.8, bias was less than 10% of the absolute flux levels, regression slope deviated from unity for less than 20% with the intercept being less than 10% of the absolute flux values, and so on. In the case of complex surface features (Hyytiälä mast in forest) the scheme proved to be robust with large deviations appearing only if the input profile data were taken outside the constant-flux layer. Comparison with the HIRLAM model showed qualitatively good agreement but also highlighted several differences between the goals, standards, and methodologies of meteorological and dispersion models. The scheme was implemented in SILAM, which served as the development platform.

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