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2481. Calculated spectra for HeH^+^
ID:
ivo://CDS.VizieR/J/MNRAS/357/471
Title:
Calculated spectra for HeH^+^
Short Name:
J/MNRAS/357/471
Date:
21 Oct 2021
Publisher:
CDS
Description:
The wavelength and Einstein A coefficient are calculated for all rotation-vibration transitions of ^4^HeH^+^, ^3^HeH^+^, ^4^He^2^H^+^ and ^3^He^2^H^+^, giving a complete line list and the partition function for ^4^HeH^+^ and its isotopologues. This opacity is included in the calculation of the total opacity of low-metallicity stars and its effect is analysed for different conditions of temperature, density and hydrogen number fraction. For a low helium number fraction (as in the Sun), it is found that HeH^+^ has a visible but small effect for very low densities ({rho}<=10^-10^g/cm^3^), at temperatures around 3500K. However, for high helium number fraction, the effect of HeH^+^ becomes important for higher densities ({rho}<=10^-6^g/cm^3^), its effect being most important for a temperature around 3500K. Synthetic spectra for a variety of different conditions are presented.
2482. Calern Observatory absolute declinations
ID:
ivo://CDS.VizieR/J/A+AS/137/269
Title:
Calern Observatory absolute declinations
Short Name:
J/A+AS/137/269
Date:
21 Oct 2021
Publisher:
CDS
Description:
A regular observational programme with a photoelectric astrolabe have been performed at ``Observatoire du Calern" (Observatoire de la Cote d'Azur, OCA, {phi}=+43{deg}44'55.011"; {lambda}=-0^h^27^m^42.44^s^, Calern, Caussols, France) for the last twenty years. It has been almost fully automatized between 1984 and 1987. Since 1988 the photoelectric astrolabe was used without any modification. In addition to determining the daily orientation of the local vertical, the yearly analysis of the residuals permits to derive corrections to the used star catalogue Vigouroux et al. (1992A&AS...96..477V). A global reduction method was applied for the ASPHO observations. The new form of the equations Martin & Leister (1997A&AS..126..169M) give us the possibility of using the entire set of the observing program using data taken at two zenith distances (30{deg} and 45{deg}). The program contains about 41648 stars' transits of 269 different stars taken at ``Observatoire du Calern" (OCA). The reduction was based on the HIPPARCOS system. We discuss the possibility of computing absolute declinations through stars belonging simultaneously to the 30{deg} and 45{deg} zenith distances programmes. The absolute declination corrections were determined for 185 stars with precision of 0.027" and the value of the determined equator correction is -0.018"+/-0.005". The instrumental effects were also determined. The mean epoch is 1995.29.
2483. Calibrated grid of rotating single star models
ID:
ivo://CDS.VizieR/J/A+A/622/A50
Title:
Calibrated grid of rotating single star models
Short Name:
J/A+A/622/A50
Date:
21 Oct 2021
Publisher:
CDS
Description:
Massive star evolution is dominated by various physical effects, including mass loss, overshooting, and rotation, but the prescriptions of their effects are poorly constrained, even affecting our understanding of the main sequence. We aim to constrain massive star evolution models using the unique testbed eclipsing binary HD166734 with new grids of MESA stellar evolution models, adopting calibrated prescriptions of overshooting, mass loss, and rotation. We introduce a novel tool: the "mass-luminosity plane" or "M-L plane", as an equivalent to the traditional HR diagram, utilising it to reproduce the testbed binary HD166734 with newly calibrated MESA stellar evolution models for single stars. We can only reproduce the Galactic binary system with an enhanced amount of core overshooting (alpha_ov_=0.5), mass loss, and rotational mixing. We can utilise the gradient in the M-L plane to constrain the amount of mass loss to 0.5-1.5 times the standard Vink et al. (2001A&A...369..574V) prescriptions, and we can exclude extreme reduction or multiplication factors. The extent of the vectors in the M-L plane leads us to conclude that the amount of core overshooting is larger than is normally adopted in contemporary massive star evolution models. We furthermore conclude that rotational mixing is mandatory to get the nitrogen abundance ratios between the primary and secondary components to be correct (3:1) in our testbed binary system. Our calibrated grid of models, alongside our new M-L plane approach, present the possibility of a widened main sequence due to an increased demand for core overshooting. The increased amount of core overshooting is not only needed to explain the extended main sequence, but the enhanced overshooting is also needed to explain the location of the upper-luminosity limit of the red supergiants. Finally, the increased amount of core overshooting has - via the compactness parameter - implications for supernova explodibility.
2484. 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.
2485. Calibrated solar S-index time series
ID:
ivo://CDS.VizieR/J/ApJ/835/25
Title:
Calibrated solar S-index time series
Short Name:
J/ApJ/835/25
Date:
21 Oct 2021
Publisher:
CDS
Description:
The most commonly used index of stellar magnetic activity is the instrumental flux scale of singly ionized calcium H & K line core emission, S, developed by the Mount Wilson Observatory (MWO) HK Project, or the derivative index R'_HK_. Accurately placing the Sun on the S scale is important for comparing solar activity to that of the Sun-like stars. We present previously unpublished measurements of the reflected sunlight from the Moon using the second-generation MWO HK photometer during solar cycle 23 and determine cycle minimum S_23,min_=0.1634+/-0.0008, amplitude {Delta}S_23_=0.0143+/-0.0012, and mean <S_23_>=0.1701+/-0.0005. By establishing a proxy relationship with the closely related National Solar Observatory Sacramento Peak calcium K emission index, itself well correlated with the Kodaikanal Observatory plage index, we extend the MWO S time series to cover cycles 15-24 and find on average <S_min_>=0.1621+/-0.0008, <{Delta}S_cyc_>=0.0145+/-0.0012, <S_cyc_>=0.1694+/-0.0005. Our measurements represent an improvement over previous estimates that relied on stellar measurements or solar proxies with non-overlapping time series. We find good agreement from these results with measurements by the Solar-Stellar Spectrograph at Lowell Observatory, an independently calibrated instrument, which gives us additional confidence that we have accurately placed the Sun on the S-index flux scale.
2486. Calibrated visibilities of {epsilon} Eri
ID:
ivo://CDS.VizieR/J/ApJ/744/138
Title:
Calibrated visibilities of {epsilon} Eri
Short Name:
J/ApJ/744/138
Date:
21 Oct 2021
Publisher:
CDS
Description:
We measured the angular diameter of the exoplanet host star {epsilon} Eridani using the Navy Optical Interferometer. We determined its physical radius, effective temperature, and mass by combining our measurement with the star's parallax, photometry from the literature, and the Yonsei-Yale isochrones, respectively. We used the resulting stellar mass of 0.82+/-0.05M_{sun}_ plus the mass function from Benedict et al. to calculate the planet's mass, which is 1.53+/-0.22M_Jupiter_. Using our new effective temperature, we also estimated the extent of the habitable zone for the system.
2487. 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.
2488. Calibration list
ID:
ivo://CDS.VizieR/J/A+A/633/A42
Title:
Calibration list
Short Name:
J/A+A/633/A42
Date:
21 Oct 2021
Publisher:
CDS
Description:
We demonstrate a novel technique for calibrating the energy scale of the EPIC-pn detector on XMM-Newton, which allows us to measure bulk flows in the intracluster medium (ICM) of the Perseus and Coma galaxy clusters. The procedure uses the fluorescent instrumental background lines present in all observations, in particular, Cu-Kalpha. By studying their spatial and temporal variations, in addition to incorporating calibration observations, we refined the absolute energy scale of the detector to better than 150km/s at the Fe-K line, a large improvement over the nominal calibration accuracy of 550km/s. With our calibration, we mapped the bulk motions over much of the central 1200 and 800kpc of Perseus and Coma, respectively, in spatial regions down to 65 and 140kpc size. We cross-checked our procedure by comparing our measurements with those found in Perseus by Hitomi for an overlapping 65 kpc square region, finding consistent results. For Perseus, there is a relative line-of-sight velocity increase of 480+/-210km/s (1sigma) at a radius of 250kpc east of the nucleus. This region is associated with a cold front, providing direct evidence of the ICM sloshing in the cluster potential well. Assuming the intrinsic distribution of bulk motions is Gaussian, its width is 214+/-85km/s, excluding systematic uncertainties. Removing the sloshing region, this is reduced to 20-150km/s, which is similar in magnitude to the Hitomi line width measurements in undisturbed regions. In Coma, the line-of-sight velocity of the ICM varies between the velocities of the two central galaxies. Maps of the gas velocity and metallicity provide clues about the merger history of the Coma, with material to the north and east of the cluster core having a velocity similar to NGC 4874, while that to the south and west has velocities close to NGC 4889. Our results highlight the difference between a merging system, such as Coma, where we observe a ~1000 km/s range in velocity, and a relatively relaxed system, such as Perseus, with much weaker bulk motions.
2489. 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.
2490. 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.

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