- ID:
- ivo://CDS.VizieR/J/A+A/363/L1
- Title:
- The distance modulus of the LMC
- Short Name:
- J/A+A/363/L1
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We use double-mode RR Lyrae (RRd) stars from the MACHO variable star database of the Large Magellanic Cloud (LMC) to estimate its distance, by utilizing photometric data, linear pulsation and stellar atmosphere models. If we set E_(B-V)_=0.11 and [M/H]=-1.5 for LMC, we get M-m=18.52mag. The fact that the distance moduli obtained in this and in our former studies of cluster RRd and Small Magellanic Cloud beat Cepheids agree so well, implies that the only serious source of error is the zero point of the temperature scale, which should not have larger than +/-0.10mag effect on the distance modulus.
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- ID:
- ivo://CDS.VizieR/J/A+A/557/A44
- Title:
- The doubly lensed quasar SDSS J1001+5027
- Short Name:
- J/A+A/557/A44
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- This paper presents optical R-band light curves and the time delay of the doubly imaged gravitationally lensed quasar SDSS J1001+5027 at a redshift of 1.838. We have observed this target for more than six years, between March 2005 and July 2011, using the 1.2-m Mercator Telescope, the 1.5-m telescope of the Maidanak Observatory and the 2-m Himalayan Chandra Telescope. Our resulting light curves are composed of 443 independent epochs, and show strong intrinsic quasar variability, with an amplitude of the order of 0.2 magnitudes. From this data, we measure the time delay using five different methods, all relying on distinct approaches. One of these techniques is a new development presented in this paper. All our time-delay measurements are perfectly compatible. By combining them, we conclude that image A is leading B by 119.3+/-3.3 days (1{sigma}, 2.8%), including systematic errors. It has been shown recently that such accurate time-delay measurements offer a highly complementary probe of dark energy and spatial curvature, as they independently constrain the Hubble constant. The next mandatory step towards using SDSS J1001+5027 in this context will be the measurement of the redshift of the lensing galaxy, in combination with deep HST imaging.
18783. The DRAO polarization survey
- ID:
- ivo://CDS.VizieR/J/A+A/448/411
- Title:
- The DRAO polarization survey
- Short Name:
- J/A+A/448/411
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- The fits files contain the observed and interpolated data of a survey of linear polarization (Stokes U and Q) at 1.4GHz, obtained with the 25.6-m telescope of the Dominion Radio Astrophysical Observatory in Canada. The angular resolution is 36 arcmin. The data are corrected for ground radiation and tied to absolute determinations of zero levels. Survey observations were carried out by drift scanning the sky between -29{deg} and +90{deg} declination. The fully Nyquist- sampled drift scans were observed in steps of 0.25{deg} to about 2.5{deg} in declination. The rms noise is 12mK in Stokes U and Q.
- ID:
- ivo://CDS.VizieR/J/A+A/352/297
- Title:
- The dust content of planetary nebulae
- Short Name:
- J/A+A/352/297
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- This table contains the dust temperatures and dust-to-gas mass ratios derived for a sample of planetary nebulae and the observational data used for these determinations
- ID:
- ivo://CDS.VizieR/J/AJ/135/1249
- Title:
- The early spectra of eta Carinae
- Short Name:
- J/AJ/135/1249
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- The observed behavior of {eta} Car from 1860 to 1940 has not been considered in most recent accounts, nor has it been explained in any quantitative model. We have used modern digital processing techniques to examine Harvard objective-prism spectra made from 1892 to 1941. Relatively high excitation HeI{lambda}4471 and [FeIII]4658 emission, conspicuous today, were weak and perhaps absent throughout those years. Feast et al. (2001MNRAS.322..741F) noted this qualitative fact for other pre-1920 spectra, but we quantify it and extend it to a time only three years before Gaviola (1953ApJ...118..234G)'s first observations of the high-excitation features. Evidently the supply of helium-ionizing photons ({lambda}<504{AA}) grew rapidly between 1941 and 1944. The apparent scarcity of such far-UV radiation before 1944 is difficult to explain in models that employ a hot massive secondary star, because no feasible dense wind or obscuration by dust would have hidden the photoionization caused by the proposed companion during most of its orbital period. We also discuss the qualitative near-constancy of the spectrum from 1900 to 1940, and {eta} Car's photometric and spectroscopic transition between 1940 and 1953.
- ID:
- ivo://CDS.VizieR/J/A+A/523/A57
- Title:
- The Earth as a transiting planet
- Short Name:
- J/A+A/523/A57
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- An important goal within the quest for detecting an Earth-like extrasolar planet, will be to identify atmospheric gaseous bio-signatures. Aims. Observations of the light transmitted through the Earth's atmosphere, as for an extrasolar planet, will be the first important step for future comparisons. We have completed observations of the Earth during a lunar eclipse, a unique situation similar to that of a transiting planet. We aim at showing what species could be detected in its atmosphere at optical wavelengths, where a lot of photons are available in the masked stellar light. We present observations of the 2008 August 16 Moon eclipse performed with the SOPHIE spectrograph at the Observatoire de Haute- Provence (France). Locating the spectrograph's fibers in the penumbra of the eclipse, the Moon irradiance is then a mix of direct, unabsorbed Sun light and solar light that has passed through the Earth's atmosphere. This mixture essentially reproduces what is recorded during the transit of an extrasolar planet. We report here the clear detection of several Earth atmospheric compounds in the transmission spectra, such as ozone, molecular oxygen, and neutral sodium as well as molecular nitrogen and oxygen through the Rayleigh signature. Moreover, we present a method that allows us to derive the thickness of the atmosphere versus the wavelength for penumbra eclipse observations. We quantitatively evaluate the altitude at which the atmosphere becomes transparent for important species like molecular oxygen and ozone, two species thought to be tightly linked to the presence of life. The molecular detections presented here are an encouraging first attempt, necessary to better prepare for the future of extremely-large telescopes and transiting Earth-like planets. Instruments like SOPHIE will be mandatory when characterizing the atmospheres of transiting Earth-like planets from the ground and searching for bio-marker signatures.
18787. The 2E Catalogue
- ID:
- ivo://CDS.VizieR/IX/13
- Title:
- The 2E Catalogue
- Short Name:
- IX/13
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- This catalog contains sources from EINSTEIN IPC (Imaging Proportional counter aboard the EINSTEIN (HEAO 2) satellite, in orbit between November 1978 and April 1981) detected during pointed observations. Note that a single source may have more than one entry in the catalog.
18788. The eclipsing binary EG Ser
- ID:
- ivo://CDS.VizieR/J/AJ/105/2291
- Title:
- The eclipsing binary EG Ser
- Short Name:
- J/AJ/105/2291
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- Stromgren b,y photometry of the detached A-type eclipsing binary EG Serpentis was obtained. Combined with the radial velocity curves in Popper [PASP, 98, 1312 (1986)], it was used to determine anew the system's parameters using the Wilson-Devinney code. The age of the system is derived from a comparison with the Bertelli et al. [A&AS, 85, 845 (1990)] isochrones. Within the accuracy limits, the results are in accordance with expectations.
- ID:
- ivo://CDS.VizieR/J/ApJ/718/683
- Title:
- The edge of the young Galactic disk
- Short Name:
- J/ApJ/718/683
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- In this work, we report and discuss the detection of two distant diffuse stellar groups in the third Galactic quadrant. They are composed of young stars, with spectral types ranging from late O to late B, and lie at galactocentric distances between 15 and 20kpc. These groups are located in the area of two cataloged open clusters (VdB-Hagen 04 and Ruprecht 30), projected toward the Vela-Puppis constellations, and within the core of the Canis Major overdensity. Their reddening and distances have been estimated by analyzing their color-color and color-magnitude diagrams, derived from deep UBV photometry. The existence of young star aggregates at such extreme distances from the Galactic center challenges the commonly accepted scenario in which the Galactic disk has a sharp cutoff at about 14kpc from the Galactic center and indicates that it extends to much greater distances (as also supported by the recent detection of CO molecular complexes well beyond this distance). While the groups we find in the area of Ruprecht 30 are compatible with the Orion and Norma-Cygnus spiral arms, respectively, the distant group we identify in the region of VdB-Hagen 04 lies in the external regions of the Norma-Cygnus arm, at a galactocentric distance (~20kpc) where no young stars have been detected so far in the optical.
- ID:
- ivo://CDS.VizieR/J/ApJ/854/99
- Title:
- The Einstein@Home gamma-ray pulsar survey. II.
- Short Name:
- J/ApJ/854/99
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We report on the analysis of 13 gamma-ray pulsars discovered in the Einstein@Home blind search survey using Fermi Large Area Telescope (LAT) Pass 8 data. The 13 new gamma-ray pulsars were discovered by searching 118 unassociated LAT sources from the third LAT source catalog (3FGL), selected using the Gaussian Mixture Model machine-learning algorithm on the basis of their gamma-ray emission properties being suggestive of pulsar magnetospheric emission. The new gamma-ray pulsars have pulse profiles and spectral properties similar to those of previously detected young gamma-ray pulsars. Follow-up radio observations have revealed faint radio pulsations from two of the newly discovered pulsars and enabled us to derive upper limits on the radio emission from the others, demonstrating that they are likely radio-quiet gamma-ray pulsars. We also present results from modeling the gamma-ray pulse profiles and radio profiles, if available, using different geometric emission models of pulsars. The high discovery rate of this survey, despite the increasing difficulty of blind pulsar searches in gamma rays, suggests that new systematic surveys such as presented in this article should be continued when new LAT source catalogs become available.