In 2008-2010, we obtained 6095 CCD frames in the BVIc photometric system for 49 classical Cepheids discovered in the ASAS-3 project. The observations were obtained on the 76-cm telescope of the South African Astronomical Observatory (SAAO, RSA) and the 40-cm telescope of the Cerro Armazones Observatory of the Catholic University of the North (OCA, Chile), with a SBIGCCD ST-10XME camera. We present tabulated observations, light curves, and revised elements for the brightness variations.
We present a new, BVIc photometric survey of the young open cluster IC 4665, which improves on previous studies of this young cluster by incorporating a rigorous standardization procedure, thus providing high-fidelity colors and magnitudes for cluster members. We use this new photometric dataset to reevaluate the properties (age and distance) of IC 4665.
We present new photometric data for 14 galactic open clusters taken by the 65cm telescope at Gunma Astronomical Observatory. They were in the anti-galactic center region selected from the Catalog of Open Cluster Data (Lynga, 1987, See Cat. <J/A+A/438/1163>). We estimated the parameters of the clusters, i.e., age, metallicity, distance, and reddening, by fitting Padova isochrones to the color-magnitude diagram.
We show that the open cluster Trumpler 20, contrary to the earlier findings, is actually an old Galactic open cluster. New CCD photometry and high-resolution spectroscopy are used to derive the main parameters of this cluster. At [Fe/H]=-0.11 for a single red giant star, the metallicity is slightly subsolar. The best fit to the colour-magnitude diagrams is achieved using a 1.3-Gyr isochrone with convective overshoot. The cluster appears to have a significant reddening at E(B-V)=0.46 (for B0 spectral type), although for red giants this high reddening yields the colour temperature exceeding the spectroscopic Teff by about 200K. Trumpler 20 is a very rich open cluster, containing at least 700 members brighter than M_V_=+4. It may extend over the field of view available in our study at 20x20arcmin^2^.
We present B, V and I CCD stellar photometry for a sample of 20 field irregular dwarf galaxies. Their corrected radial velocity is V_0_<500km/s. Most of them have been resolved into stars for the first time. Based on photometry of their brightest blue stars we have derived the following distances: 5.9Mpc (UGC 685), 5.4Mpc (UGC 1281), 7.2Mpc (UGC 3303), 7.0Mpc (UGC 3476), 7.3:Mpc (UGC 3600), 7.2:Mpc (UGC 3698), 7.9Mpc (NGC 2337), 8.6Mpc (UGC 3817), 5.7Mpc (UGC 3860), 5.6Mpc (UGC 4426), >=7.9Mpc (F 565-v1), 7.4:Mpc (UGC 5086), 7.1Mpc (UGC 5272), 5.9Mpc (UGC 5340), 7.1Mpc (UGC 5427), 2.7:Mpc (UGC 5456), 6.6Mpc (NGC 3274), 9.3Mpc (UGC 5889), 5.2Mpc (NGC 5238), and 8.0Mpc (UGC 9405). Our sample exhibits diverse morphological properties evidently caused by their different starburst activity. The galaxy sample has a median integral absolute magnitude M_B_=-14.6 and a median integral colour (B-V)_T_=+0.47. One dwarf, UGC 5340, stands out by its very blue colour, (B-V)_T_=+0.18, and by its high M(HI)/L ratio, as expected for young galaxies. Four objects of the sample are IRAS sources. Being well isolated systems, the considered galaxies may be used to estimate a local value of the Hubble parameter, H=V_0_/D. For half of the sample galaxies their individual H- values are concentrated within [58-68]km/s/Mpc with a median of 65km/s/Mpc.
We present a BVI photometric and astrometric catalogue of the open cluster NGC 3960, down to limiting magnitude V~22, obtained from observations taken with the Wide Field Imager camera at the MPG/ESO 2.2m Telescope at La Silla. The photometry of all the stars detected in our field of view has been used to estimate a map of the strong differential reddening affecting this area. Our results indicate that, within the region where the cluster dominates, the E(V-I) values range from 0.21 up to 0.78, with E(V-I)=0.36 (E(B-V)=0.29) at the nominal cluster centroid position; color excesses E(V-I) up to 1 mag have been measured in the external regions of the field of view where field stars dominate. The reddening-corrected color-magnitude diagram (CMD) allows us to conclude that the cluster has an age between 0.9 and 1.4Gyr and a distance modulus of (V-M_V)_0=11.35. Based on observations made with the European Southern Observatory telescopes obtained from the the ESO/ST-ECF Science Archive Facility.
A method for determining distances to dark clouds and Bok globules based on broad-band optical and near-infrared photometry is presented. In this method, intrinsic colour indices of stars projected towards the direction of a cloud are computed by dereddening the observed colour indices using various trial values of extinction A_V_ and a standard extinction law. The computed intrinsic colour indices for a star are then compared with the intrinsic colour indices of normal main-sequence stars and a spectral type is assigned to the star for which the computed colour indices best match the standard intrinsic colour indices. Distances (d) to the stars are determined using the A_V_ and absolute magnitudes (M_V_) corresponding to the spectral types thus obtained. A plot of A_V_ against d undergoes a sharp rise at a distance corresponding to the distance to the cloud. Using this method, we have determined a distance of 550pc to the cometary globule CG 12.
We present high-resolution HST imaging in the optical (WFPC2) and near-infrared (NICMOS) of a disk region 1kpc northeast of the starburst core in the nearby galaxy M82.
We present wide-field BVI photometry for about 11500 stars in the low-metallicity cluster NGC 5466. We have detected the red giant branch bump for the first time, although it is at least 0.2mag fainter than expected relative to the turnoff. The number of red giants (relative to main-sequence turnoff stars) is in excellent agreement with stellar models from the Yonsei-Yale and Teramo groups, and slightly high compared to Victoria-Regina models. This adds to evidence that an abnormally large ratio of red giant to main-sequence stars is not correlated with cluster metallicity.
BVI phot. of CFRS 0300+00 & 1415+52 fields galaxies
Short Name:
J/A+A/435/507
Date:
21 Oct 2021
Publisher:
CDS
Description:
This catalog contains 75 field galaxies in two 10'x10' CFRS fields 0300+00 and 1415+52 with HST/WFPC2 image and deep ISOCAM observations. They are not detected in the ISO observations to a detection limit of 300{mu}Jy at 5{sigma} level. Magnitudes and Structural parameters in three HST bands and according morphological classification are presented
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