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 Physics , 2000, Abstract: Relying on his photometry of galaxies, Holmberg (1958) found, more than 40 years ago, that the color indices of paired galaxies were closely correlated. Our deep broad-band BVRI CCD photometry of 45 (S+S) pairs from the Karachentsev (1972) catalogue (see Hernandez Toledo and Puerari, this volume), and additional (B-V) color information from the literature (50 extra (S+S) pairs), help us to confirm the effect. This "Holmberg Effect" has long been remained unverified and not explained yet.
 Physics , 1999, Abstract: Detailed BVRI-Halpha photometry has been obtained for the ring galaxy HRG 2302. This is probably a still interacting system which shows two principal components: the target, which is a knotted ringed-disk, and the intruder, an elongated galaxy with two substructures probably caused by the interaction. The existence of H II emission regions is suggested by Halpha images and medium dispersion spectra of the three brightest parts of this system. Analysis of a color-color diagram suggests recent star formation, in agreement with the behavior of interacting galaxies with nuclear emission. HRG 2302 has been previously classified as a Polar Ring galaxy (Faundez-Abans & de Oliveira-Abans 1998a), but we have reclassified it as Elliptical-Knotted, based on the morphological substructures found. This work reveals, for the first time, the existence of at least 15 fainter galaxies in the field within ~4 arcmin around HRG 2302, giving positions and integrated standard magnitudes for all of them.
 Physics , 2014, Abstract: New BVRI CCD observations of the semi-detached eclipsing binary EG Cep are presented. The observed light curves are analyzed with the Wilson-Devinney program and new geometrical and photometric elements are derived. These elements are used to compute the physical parameters of the system in order to study its evolutionary status.
 Physics , 2002, DOI: 10.1051/0004-6361:20020439 Abstract: Johnson BVRI photometric data for individual components of binary systems have been provided by ten Brummelaar et al. (2000). This is essential because such binaries could play a critical role in calibrating the single-star stellar evolution theory. While they derived the effective temperature from their estimated spectral type, we infer metallicity-dependent Teffs from a minimizing method fitting the B-V, V-R and V-I colours. For this purpose, a grid of 621,600 flux distributions were computed from the Basel Stellar Library (BaSeL 2.2) of model-atmosphere spectra, and their theoretical colours compared with the observed photometry. As a matter of fact, the BaSeL colours show a very good agreement with the BVRI metallicity-dependent empirical calibrations of Alonso et al. (1996), temperatures being different by 3+-3 % in the range 4000-8000 K for dwarf stars. Before deriving the metallicity-dependent Teff from the BaSeL models, we paid particular attention to the influence of reddening and stellar rotation. A comparison between the MExcess code and neutral hydrogen column density data shows a good agreement for the sample but we point out a few directions where the MExcess model overestimates the E(B-V) colour excess. Influence of stellar rotation on the BVRI colours can be neglected except for 5 stars with large vsini, the maximum effect on temperature being less than 5%. Our final results are in good agreement with previous spectroscopic determinations available for a few primary components, and with ten Brummelaar et al. below ~10,000 K. Nevertheless, we obtain an increasing disagreement with their Teffs beyond 10,000 K. Finally, we provide a revised Hertzsprung-Russell diagram for the systems with the more accurately determined temperatures. (Abridged)
 Q. -z. Ye Physics , 2010, DOI: 10.1088/0004-6256/141/2/32 Abstract: We present the results of BVRI photometry and classification of 53 unusual asteroids, including 35 near-Earth asteroids (NEAs), 6 high eccentricity/inclination asteroids, and 12 recently-identified asteroid-pair candidates. Most of these asteroids were not reportedly classified prior to this work. For the few asteroids that have been previously studied, the results are generally in rough agreement. In addition, we merge the results from several photometric/spectroscopic surveys to create a largest-ever sample with 449 spectrally classified NEAs for statistical analysis. We identify a "transition point" of the relative number of C/X-like and S-like NEAs at H~18<=>D~1km with confidence level at ~95% or higher. We find that the C/X-like:S-like ratio for 18<=H<22 is about two times higher than that of H<18 (0.33+/-0.04 versus 0.17+/-0.02), virtually supporting the hypothesis that smaller NEAs generally have less weathered surface (therefore, less reddish appearance) caused by younger collision ages.
 Physics , 2001, DOI: 10.1086/323970 Abstract: We present optical photometry of one Type IIn supernova (1994Y) and nine Type Ia supernovae (1993Y, 1993Z, 1993ae, 1994B, 1994C, 1994M, 1994Q, 1994ae, and 1995D). SN 1993Y and SN 1993Z appear to be normal SN Ia events with similar rates of decline, but we do not have data near maximum brightness. The colors of SN 1994C suggest that it suffers from significant reddening or is intrinsically red. The light curves of SN 1994Y are complicated; they show a slow rise and gradual decline near maximum brightness in $VRI$ and numerous changes in the decline rates at later times. SN 1994Y also demonstrates color evolution similar to that of the SN IIn 1988Z, but it is slightly more luminous and declines more rapidly than SN 1988Z. The behavior of SN1994Y indicates a small ejecta mass and a gradual strengthening of the H$\alpha$ emission relative to the continuum.
 Peter B. Stetson Physics , 2000, DOI: 10.1086/316595 Abstract: Stars appearing in CCD images obtained over 224 nights during the course of 69 observing runs have been calibrated to the Johnson/Kron-Cousins BVRI photometric system defined by the equatorial standards of Landolt (1992, AJ, 104, 340). More than 15,000 stars suitable for use as photometric standards have been identified, where "suitable" means that the star has been observed five or more times during photometric conditions and has a standard error of the mean magnitude less than 0.02 mag in at least two of the four bandpasses, and shows no significant evidence of intrinsic variability. Many of these stars are in the same fields as Landolt's equatorial standards or Graham's (1982, PASP, 94, 244) southern E-region standards, but are considerably fainter. This enhances the value of those fields for the calibration of photometry obtained with large telescopes. Other standards have been defined in fields containing popular objects of astrophysical interest, such as star clusters and famous galaxies, extending Landolt-system calibrators to declinations far from the equator and to stars of sub-Solar chemical abundances. I intend to continue to improve and enlarge this set of photometric standard stars as more observing runs are reduced. The full current database of photometric indices is being made freely available via a site on the World-Wide Web, or by direct request to the author. Although the contents of the database will evolve in detail, at any given time it should represent the largest sample of precise BVRI broad-band photometric standards available anywhere.
 Revista mexicana de astronomía y astrofísica , 2008, Abstract:
 Physics , 2014, DOI: 10.1088/0004-6256/148/4/60 Abstract: We present optical (BVRI) photometric measurements of a sample of 76 common proper motion wide separation main sequence binary pairs. The pairs are composed of a F-, G-, or K-type primary star and an M-type secondary. The sample is selected from the revised NLTT catalog and the LSPM catalog. The photometry is generally precise to 0.03 mag in all bands. We separate our sample into two groups, dwarf candidates and subdwarf candidates, using the reduced proper motion (RPM) diagram constructed with our improved photometry. The M subdwarf candidates in general have larger $V-R$ colors than the M dwarf candidates at a given $V-I$ color. This is consistent with an average metallicity difference between the two groups, as predicted by the PHOENIX/BT-Settl models. The improved photometry will be used as input into a technique to determine the metallicities of the M-type stars.
 Physics , 2010, DOI: 10.1111/j.1365-2966.2010.17212.x Abstract: Using the Hyperz code and a template spectral library which consists of 4 observed galaxy spectra from Coleman, Wu & Weedman (CWW, 1980) and 8 spectral families built with evolutionary population synthesis models, we present photometric redshift estimates (photo-z) for a spectroscopic sample of 6,531 galaxies, and morphologies for a morphological sample of 1,502 bright galaxies. All galaxies are matched with the SDSS DR7 and GALEX DR4. The inclusion of Fuv or Nuv or both photometry decreases the number of catastrophic identifications (CIs, |z_phot -z_spec| > 1.0). If CIs are removed, the inclusion of both Fuv and Nuv photometry mainly increases the number of non-CIs in the low redshift, g-r < 0.8 and fainter r-magnitude regions. The inclusion of binary interactions (BIs) mainly increases the number of non-CIs and decreases the deviations in the 0.3 < g-r < 0.8 region in the case of only using optical photometry. The inclusion of UV photometry would decrease and increase the probability that early types are classified as Burst and E types, respectively, and increase that late types are classified as CWW-Sbc and CWW-Scd types. If CIs are excluded, the inclusion of UV data mainly raises the identifications of late types in all redshift, bluer g-r and r > 14 regions. Moreover, BIs mainly affect the determinations of E and S0 types. Nuv -u = 1.94 and 5.77-1.47(u-r) = Fuv discriminators can be used as morphology selection indicators. These two criteria have comparable reliability and completeness for selecting early- and late-type galaxies to C=2.6 criterion and higher completeness for early-type selection than u-r=2.22 criterion.
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