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1921. Calibrated griz magnitudes of Tycho stars
ID:
ivo://CDS.VizieR/J/PASP/120/1128
Title:
Calibrated griz magnitudes of Tycho stars
Short Name:
J/PASP/120/1128
Date:
21 Oct 2021
Publisher:
CDS
Description:
Photometric calibration at an accuracy of ~5% in an arbitrary celestial location is frequently needed. However, existing all-sky astronomical catalogue do not reach this accuracy, and time consuming photometric calibration procedures are required. I fitted the Hipparcos B_T_, and V_T_ magnitudes, along with the 2MASS J, H, and K magnitudes of Tycho-2 catalog-stars with stellar spectral templates. From the best fit spectral template derived for each star, I calculated its synthetic SDSS griz magnitudes, and constructed an all-sky catalog of griz magnitudes of bright stars (V<12). Testing this method on SDSS photometric telescope observations, I find that the photometric accuracy, for a single star, is usually about 0.12, 0.12, 0.10 and 0.08 mag (1sigma), for the g, r, i, and z-bands, respectively. However, by using ~10 such stars, the typical errors per calibrated field (systematic + statistical) can be reduced to about 0.04, 0.03, 0.02, and 0.02 mag, in the g, r, i, and z-bands, respectively. Therefore, in cases for which several calibration stars can be observed in the field of view of an instrument, it is possible to photometrically calibrate the image.
1922. Calibrating Broad Band X-ray Telescope
ID:
ivo://CDS.VizieR/J/ApJS/96/303
Title:
Calibrating Broad Band X-ray Telescope
Short Name:
J/ApJS/96/303
Date:
21 Oct 2021
Publisher:
CDS
Description:
This paper describes the calibration of the two solid-state Si(Li) X-ray detectors and the X-ray telescopes that flew as part of Goddard Space Flight Center's Broad Band X-Ray Telescope (BBXRT) experiment on board the space shuttle Columbia in 1990 December. During the 9 day shuttle mission, BBXRT performed ~150 observations of 82 celestial sources. The content of the archive is summarised here. Although BBXRT had a relatively short life, it stands as a milestone in X-ray astronomy as being the first instrument to offer moderate spectral resolution over a wide bandpass (0.3-12.0keV). Among other things, this paper discusses the effective area calibration of the instrument, the flux calibration and flux corrections for off-axis observations, the detector background, and optimal background subtraction techniques. The on-axis effective area calibration for the central detector elements was performed using data from the Crab Nebula, while other carefully selected targets were used for calibration of the outer detector elements. The remaining systematic uncertainties in the effective area calibration for point sources observed both on and off axis are generally less than 5%-10%. The energy scale is known to better than 0.5% at 6.0 keV for both detectors. The results presented here have an impact on the calibration of other medium resolution X-ray experiments such as the CCDs on board ASCA (Astro-D) as well as the Advanced X-Ray Astrophysics Facility detectors.
1923. Calibration of Cepheid Period/Luminosity relation
ID:
ivo://CDS.VizieR/J/A+A/476/73
Title:
Calibration of Cepheid Period/Luminosity relation
Short Name:
J/A+A/476/73
Date:
21 Oct 2021
Publisher:
CDS
Description:
The universality of the Cepheid period-luminosity (PL) relations has been under discussion since metallicity effects were assumed to play a role in the value of the intercept and, more recently, of the slope of these relations. The goal of the present study is to calibrate the Galactic PL relations in various photometric bands (from B to K) and to compare the results to the well-established PL relations in the LMC. We use a set of 59 calibrating stars, the distances of which are measured using five different distance indicators: Hubble Space Telescope and revised Hipparcos parallaxes, infrared surface brightness and interferometric Baade-Wesselink parallaxes, and classical Zero-Age-Main-Sequence-fitting parallaxes for Cepheids belonging to open clusters or OB stars associations. A detailed discussion of absorption corrections and projection factor to be used is given.
1924. Calibration of G passband for Gaia DR1
ID:
ivo://CDS.VizieR/J/A+A/608/L8
Title:
Calibration of G passband for Gaia DR1
Short Name:
J/A+A/608/L8
Date:
21 Oct 2021
Publisher:
CDS
Description:
On September 2016 the first data from Gaia were released (DR1). The first release included photometry for over 109 sources in the very broad G system. To test the correspondence between G magnitudes in DR1 and the synthetic equivalents derived using spectral energy distributions from observed and model spectrophotometry. To correct the G passband curve and to measure the zero point in the Vega system. Methods. I have computed the synthetic G and Tycho-2 BTVT photometry for a sample of stars using the Next Generation Spectral Library (NGSL) and the Hubble Space Telescope (HST) CALSPEC spectroscopic standards. I have found that the nominal G passband curve is too blue for the DR1 photometry, as shown by the presence of a color with an exponent of 0.783 eliminates the color term. The corrected passband has a Vega zero point of 0.070+/-0.004 magnitudes.
1925. Calibration of H{alpha} fluxes in SHS
ID:
ivo://CDS.VizieR/J/MNRAS/440/1080
Title:
Calibration of H{alpha} fluxes in SHS
Short Name:
J/MNRAS/440/1080
Date:
21 Oct 2021
Publisher:
CDS
Description:
The AAO/UKST SuperCOSMOS H{alpha} Survey (SHS) was, when completed in 2003, a powerful addition to extant wide-field surveys. The combination of areal coverage, spatial resolution and sensitivity in a narrow imaging band, still marks it out today as an excellent resource for the astronomical community. The 233 separate fields are available online in digital form, with each field covering 25deg^2^. The SHS has been the motivation for equivalent surveys in the north, and new digital H{alpha} surveys now beginning in the south such as VPHAS+. It has been the foundation of many important discovery projects with the Macquarie/AAO/Strasbourg H{alpha} planetary nebula project being a particularly successful example. However, the full potential of the SHS has been hampered by lack of a clear route to acceptable flux calibration from the base photographic data. We have determined the calibration factors for 170 individual SHS fields, and present a direct pathway to the measurement of integrated H{alpha} fluxes and surface brightnesses for resolved nebulae detected in the SHS. We also include a catalogue of integrated H{alpha} fluxes for >100 planetary and other nebulae measured from the SHS, and use these data to show that fluxes, accurate to +/-0.10-0.14dex (~25-35%), can be obtained from these fields. For the remaining 63 fields, a mean calibration factor of 12.0 counts/pixel/R can be used, allowing the determination of reasonable integrated fluxes accurate to better than +/-0.2dex (~50%). We outline the procedures involved and the caveats that need to be appreciated in achieving such flux measurements. This paper forms a handy reference source that will significantly increase the scientific utility of the SHS.
1926. Calibration of RAVE distances with Hipparcos
ID:
ivo://CDS.VizieR/J/MNRAS/436/1343
Title:
Calibration of RAVE distances with Hipparcos
Short Name:
J/MNRAS/436/1343
Date:
21 Oct 2021
Publisher:
CDS
Description:
A magnitude limited population of 18808 Hipparcos stars is used to calibrate distances for 52794 RAVE stars, including dwarfs, giants, and pre-main sequence stars. I give treatments for a number of types of bias affecting calculation, including bias from the non-linear relationship between the quantity of interest (e.g., distance or distance modulus) and the measured quantity (parallax or visual magnitude), the Lutz-Kelker bias, and bias due to variation in density of the stellar population. The use of a magnitude bound minimises the Malmquist and the Lutz-Kelker bias, and avoids a measurement bias because Hipparcos parallaxes are more accurate for brighter stars. The calibration is applicable to stars in 2MASS when there is some way to determine stellar class with reasonable confidence. For RAVE this is possible for hot dwarfs and using log g. The accuracy of the calibration is tested against Hipparcos stars with better than 2% parallax errors, and by comparison of the RAVE velocity distribution with that of Hipparcos, and is found to improve upon previous estimates of luminosity distance. An estimate of the LSR from RAVE data, (U0, V0, W0) = (14.9-1.7, 15.3-0.4, 6.9-0.1)km/s shows excellent agreement with the current best estimate from XHIP. The RAVE velocity distribution confirms the alignment of stellar motions with spiral structure.
1927. Calibration of Stromgren phot. for late-type stars
ID:
ivo://CDS.VizieR/J/A+A/498/527
Title:
Calibration of Stromgren phot. for late-type stars
Short Name:
J/A+A/498/527
Date:
21 Oct 2021
Publisher:
CDS
Description:
The use of model atmospheres for deriving stellar fundamental parameters, such as Teff, log(g), and [Fe/H], will increase as we find and explore extreme stellar populations where empirical calibrations are not yet available. Moreover, calibrations for upcoming large satellite missions of new spectrophotometric indices, similar to the uvby-Hbeta system, will be needed. We aim to test the power of theoretical calibrations based on a new generation of MARCS models by comparisons with observational photometric data. We calculated synthetic uvby-Hbeta colour indices from synthetic spectra. A sample of 367 field stars, as well as stars in globular clusters, is used for a direct comparison of the synthetic indices versus empirical data and for scrutizing the possibilities of theoretical calibrations for temperature, metallicity, and gravity. We show that the temperature sensitivity of the synthetic (b-y) colour is very close to its empirical counterpart, whereas the temperature scale based upon Hbeta shows a slight offset. The theoretical metallicity sensitivity of the m1 index (and for G-type stars its combination with c1) is somewhat higher than the empirical one, based upon spectroscopic determinations. The gravity sensitivity of the synthetic c1 index shows satisfactory behaviour when compared to observations of F stars. For stars cooler than the sun, a deviation is significant in the c1-(b-y) diagram. The theoretical calibrations of (b-y), (v-y), and c1 seem to work well for Pop II stars and lead to effective temperatures for globular cluster stars supporting recent claims that atomic diffusion occurs in stars near the turnoff point of NGC 6397. Synthetic colours of stellar atmospheres can indeed be used, in many cases, to derive reliable fundamental stellar parameters. The deviations seen when compared to observational data could be due to incomplete linelists but are possibly also due to the effects of assuming plane-parallel or spherical geometry and LTE.
1928. Calibration of the mid-IR Tully-Fisher relation
ID:
ivo://CDS.VizieR/J/ApJ/765/94
Title:
Calibration of the mid-IR Tully-Fisher relation
Short Name:
J/ApJ/765/94
Date:
21 Oct 2021
Publisher:
CDS
Description:
Distance measures on a coherent scale around the sky are required to address the outstanding cosmological problems of the Hubble constant and of departures from the mean cosmic flow. The correlation between galaxy luminosities and rotation rates can be used to determine the distances to many thousands of galaxies in a wide range of environments potentially out to 200Mpc. Mid-infrared (3.6{mu}m) photometry with the Spitzer Space Telescope is particularly valuable as a source of luminosities because it provides products of uniform quality across the sky. From a perch above the atmosphere, essentially the total magnitude of targets can be registered in exposures of a few minutes. Extinction is minimal and the flux is dominated by the light from old stars, which is expected to correlate with the mass of the targets. In spite of the superior photometry, the correlation between mid-infrared luminosities and rotation rates extracted from neutral hydrogen profiles is slightly degraded from the correlation found with I-band luminosities. A color correction recovers a correlation that provides comparable accuracy to that available at the I band (~20% 1{sigma} in an individual distance) while retaining the advantages identified above. Without color correction, the relation between linewidth and [3.6] magnitudes is M^b,i,k,a^_[3.6]_=-20.34-9.74(logW^i^_mx_-2.5). This description is found with a sample of 213 galaxies in 13 clusters that define the slope and 26 galaxies with Cepheid or tip of the red giant branch distances that define the zero point. A color-corrected parameter M_c[3.6]_ is constructed that has reduced scatter: M_c[3.6]_=-20.34-9.13(logW_mx_^i^-2.5). Consideration of the seven calibration clusters beyond 50Mpc, outside the domain of obvious peculiar velocities, provides a preliminary Hubble constant estimate of H_0_=74+/-4km/s.M/pc.
1929. Calibration of the Tully-Fischer relation
ID:
ivo://CDS.VizieR/J/ApJ/533/744
Title:
Calibration of the Tully-Fischer relation
Short Name:
J/ApJ/533/744
Date:
21 Oct 2021
Publisher:
CDS
Description:
The correlation between the luminosities and rotation velocities of galaxies can be used to estimate distances to late-type galaxies. It is an appropriate moment to reevaluate this method given the great deal of new information available. The major improvements described here include: (1) the template relations can now be defined by large, complete samples, (3) the samples are drawn from a wide range of environments, (3) the relations are defined by photometric information at the B, R, I, and K' bands, (4) the multiband information clarifies problems associated with internal reddening, (5) the template zero points are defined by 24 galaxies with accurately known distances, and (6) the relations are applied to 12 clusters scattered across the sky and out to velocities of 8000km/s.
1930. Calibration sample UBV and GALEX photometry
ID:
ivo://CDS.VizieR/J/other/PASA/37.22
Title:
Calibration sample UBV and GALEX photometry
Short Name:
J/other/PASA/37.
Date:
21 Oct 2021
Publisher:
CDS
Description:
We derive transformation equations between GALEX and UBV colours by using the reliable data of 556 stars. We present two sets of equations: as a function of (only) luminosity class and as a function of both luminosity class and metallicity. The metallicities are provided from the literature, while the luminosity classes are determined by using the PARSEC mass tracks in this study. Small colour residuals and high squared correlation coefficients promise accurate derived colours. The application of the transformation equations to 70 stars with reliable data shows that the metallicity plays an important role in estimation of more accurate colours.

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