- ID:
- ivo://CDS.VizieR/J/MNRAS/345/949
- Title:
- UBRI photometry of NGC 3379 globular clusters
- Short Name:
- J/MNRAS/345/949
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present wide-area UBRI photometry for globular clusters around the Leo group galaxy NGC 3379. Globular cluster candidates are selected from their B-band magnitudes and their (U-B)_0_ versus (B-I)_0_ colours. A colour-colour selection region was defined from photometry of the Milky Way and M31 globular cluster systems. We detect 133 globular cluster candidates, which supports previous claims of a low specific frequency for NGC 3379.
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- ID:
- ivo://CDS.VizieR/J/AJ/128/544
- Title:
- UBRI Photometry of Quasars
- Short Name:
- J/AJ/128/544
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present UBRI photometry and spectra for 60 quasars found within 1{deg}^2^ centered on the J0053+1234 region, which has been the subject of the Caltech Faint Galaxy Redshift Survey. Candidate quasars were selected by their ultraviolet excess with respect to the stellar locus and confirmed spectroscopically. The quasars span a wide range in brightness (17.5<B<21.6) and redshift (0.43<z<2.38).
- ID:
- ivo://CDS.VizieR/J/AJ/121/2381
- Title:
- UBRI photometry of radio galaxies
- Short Name:
- J/AJ/121/2381
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We describe a new estimate of the radio galaxy 1.4 GHz luminosity function and its evolution at intermediate redshifts (z~0.4). Photometric redshifts and color selection have been used to select B_J_<23.5 early-type galaxies from the Panoramic Deep Fields, a multicolor survey of two 25deg^2^ fields. Approximately 230 radio galaxies have then been selected by matching early-type galaxies with NVSS radio sources brighter than 5mJy. Estimates of the 1.4GHz luminosity function of radio galaxies measure significant evolution over the observed redshift range. For an {Omega}_M_=1 cosmology the evolution of the radio power is consistent with luminosity evolution where P(z)~P(0)(1+z)^K_L_^ and 3<K_L_<5. The observed evolution is similar to that observed for UVX and X-ray selected active galactic nuclei and is consistent with the same physical process being responsible for the optical and radio luminosity evolution of active galactic nuclei.
- ID:
- ivo://CDS.VizieR/J/AJ/115/1076
- Title:
- UBRVI photometry of Collinder 110
- Short Name:
- J/AJ/115/1076
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- Results of photoelectric UBVRI photometry of 78 stars and photographic PDS and CCD photometry for 437 stars are presented for Collinder 110, an old open cluster at low Galactic latitude. Proper motions obtained from Lick Sky Survey plates were used to identify 39 stars as foreground objects. The cluster's reddening, distance, and age are estimated as E(B-V)=0.50+/-0.03mag, r=1950+/-300pc, and t=1.4+/-0.3Gyr, assuming a solar metal abundance.
- ID:
- ivo://CDS.VizieR/J/AJ/145/37
- Title:
- UBVI and H{alpha} CCD photometry of NGC 6231
- Short Name:
- J/AJ/145/37
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We have performed new wide-field photometry of the young open cluster NGC6231 to study the shape of the initial mass function (IMF) and mass segregation. We also investigated the reddening law toward NGC6231 from optical to mid-infrared color excess ratios, and found that the total-to-selective extinction ratio is R_V_=3.2, which is very close to the normal value. But many early-type stars in the cluster center show large color excess ratios. We derived the surface density profiles of four member groups, and found that they reach the surface density of field stars at about 10', regardless of stellar mass. The IMF of NGC6231 is derived for the mass range 0.8-45M_{sun}_. The slope of the IMF of NGC6231 ({Gamma}=-1.1+/-0.1) is slightly shallower than the canonical value, but the difference is marginal. In addition, the mass function varies systematically, and is a strong function of radius-it is very shallow at the center, and very steep at the outer ring suggesting the cluster is mass segregated. We confirm the mass segregation for the massive stars (m>~8 M_{sun}_) by a minimum spanning tree analysis. Using a Monte Carlo method, we estimate the total mass of NGC6231 to be about 2.6(+/-0.6)*10^3^M_{sun}_. We constrain the age of NGC 6231 by comparison with evolutionary isochrones. The age of the low-mass stars ranges from 1 to 7Myr with a slight peak at 3Myr. However, the age of the high-mass stars depends on the adopted models and is 3.5+/-0.5Myr from the non-rotating or moderately rotating models of Brott et al. (2011, cat. J/A+A/530/A115) as well as the non-rotating models of Ekstrom et al. (2012, cat. J/A+A/537/A146). But the age is 4.0-7.0Myr if the rotating models of Ekstrom et al. (2012, cat. J/A+A/537/A146) are adopted. This latter age is in excellent agreement with the timescale of ejection of the high-mass runaway star HD153919 from NGC6231, albeit the younger age cannot be entirely excluded.
- ID:
- ivo://CDS.VizieR/J/A+A/416/537
- Title:
- UBVI and HST photometry of young stellar clusters
- Short Name:
- J/A+A/416/537
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- These tables contain a combination of ground-based and HST archive data for stellar clusters in 18 nearby spiral galaxies. Structural parameters for each cluster are measured on HST images, while UBVI photometry is from ground-based data obtained with the Danish 1.54m telescope at ESO La Silla, the 2.56m Nordic Optical Telescope in La Palma, Canary Islands, and the 3m Shane Telescope at Lick Observatory, California. Photometry in the STMAG system based on the HST data is also given (table 7) for each cluster for the available bandpasses.
- ID:
- ivo://CDS.VizieR/J/A+A/407/919
- Title:
- UBVI and JHK photometry in Lindsay 1
- Short Name:
- J/A+A/407/919
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- Results of UBVI stellar photometry of SMC star cluster Lindsay 1. The frames were obtained in October 1999 with the 1.3m Warsaw telescope, Las Campanas Observatory with the 2048x2048 CCD camera. Missing magnitudes and colors of the stars are replaced with value 100.00.
- ID:
- ivo://CDS.VizieR/J/A+A/407/527
- Title:
- UBVIc and JHK photometry of NGC 1582 and NGC 1663
- Short Name:
- J/A+A/407/527
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present CCD UBV(I)c observations obtained in the field of the previously unstudied northern open clusters NGC 1582 and NGC 1663. For the former, we also provide high-resolution spectra of the brightest stars and complement our data with Two-Micron All Sky-Survey (2MASS) near-infrared photometry and with astrometric data from the Tycho-2 catalog. From the analysis of all these data, we argue that NGC 1582 is a very poor, quite large and heavily contaminated open cluster. It turns out to have a reddening E(B-V)=0.35+/-0.03, to be situated 1100+/-100pc from the Sun and to have an age of 300+/-100Myr. On the other hand, we were not able to unambiguously clarify the nature of NGC 1663. By assuming it is a real cluster and from the analysis of its photometric diagrams, we found a color excess value E(B-V)=0.20, an intermediate age value (~2000Myr) and a distance of about 700pc. The distribution of the stars in the region however suggests we are probably facing an open cluster remnant. As an additional result, we obtained aperture photometry of three previously unclassified galaxies placed in the field of NGC 1663 and performed a preliminary morphological classification of them.
- ID:
- ivo://CDS.VizieR/J/AJ/143/41
- Title:
- UBVIc CCD photometry of star clusters Tr14 and Tr16
- Short Name:
- J/AJ/143/41
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present new UBVIc CCD photometry of the young open clusters Trumpler 14 (Tr 14) and Trumpler 16 (Tr 16) in the {eta} Carina Nebula (NGC 3372). We also identify the optical counterpart of Chandra X-ray sources and Two Micron All Sky Survey point sources. The members of the clusters were selected from the proper-motion study, spectral types, reddening characteristics, and X-ray or near-IR excess emission. An abnormal reddening law R_V,cl_=4.4+/-0.2 was obtained for the stars in the {eta} Carina Nebula using the 141 early-type stars with high proper-motion membership probability (P_{mu}_>=70%). We determined the distance to each cluster and conclude that Tr 14 and Tr 16 have practically the same distance modulus of V_0_-M_V_=12.3+/-0.2mag (d=2.9+/-0.3kpc). The slope of the initial mass function was determined to be {Gamma}=-1.3+/-0.1 for Tr 14, {Gamma}=-1.3+/-0.1 for Tr 16, and {Gamma}=-1.4+/-0.1 for all members in the observed region for the stars with log m>=0.2. We also estimated the age of the clusters to be about 1-3Myr from the evolutionary stage of evolved stars and low-mass pre-main-sequence stars.
- ID:
- ivo://CDS.VizieR/J/A+A/381/884
- Title:
- UBVI CCD photometry in NGC 2571
- Short Name:
- J/A+A/381/884
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- CCD UBVI imaging photometry was carried out in the field of the open cluster NGC 2571. From the analysis of our data we state the cluster is at a distance of 1380+/-130pc and its age is 50+/-10x10^6yr. The cluster mass function has a slope larger than a typical Salpeter's law. There are two notorious features in NGC 2571: the cluster contains a high proportion of stars located below the reference line that are serious candidates to be metallic line stars (probably Am-Fm), and shows also a sharp gap along its main sequence that cannot be explained by a random process nor by a biased rejection of cluster members. A striking blue object was detected in the cluster field that could be a white dwarf candidate. We carried out CCD imaging photometry in the Kron-Cousins UBVI system on April 27 and 29, 1994 using a 1024x1024pix CCD with a scale of 0.37"/pix and a field of view of 6.3'x6.3' attached to the 1.54-m Danish telescope at ESO, La Silla, Chile.
