- ID:
- ivo://CDS.VizieR/J/A+A/430/19
- Title:
- VRI photometry of Abell 3921 galaxies
- Short Name:
- J/A+A/430/19
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present the analysis and results of a new VRI photometric and spectroscopic survey of the central ~1.8x1.2Mpc^2^ region of the galaxy cluster A3921 (z=0.094). We detect the presence of two dominant clumps of galaxies with a mass ratio of ~5: a main cluster centred on the Brightest Cluster Galaxy (BCG) (A3921-A), and an NW sub-cluster (A3921-B) hosting the second brightest cluster galaxy. The distorted morphology of the two sub-clusters suggests that they are interacting, while the velocity distribution of 104 confirmed cluster members does not reveal strong signatures of merging.
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Search Results
- ID:
- ivo://CDS.VizieR/J/AJ/127/840
- Title:
- VRI photometry of Fornax red giants
- Short Name:
- J/AJ/127/840
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- Near-infrared spectra were obtained for 117 red giants in the Fornax dwarf spheroidal galaxy with the FORS1 spectrograph on the VLT, in order to study the metallicity distribution of the stars and to lift the age-metallicity degeneracy of the red giant branch (RGB) in the color-magnitude diagram (CMD). Metallicities are derived from the equivalent widths of the infrared calcium triplet lines at 8498, 8542, and 8662{AA} calibrated with data from globular clusters, the open cluster M67, and the LMC. For a substantial portion of the sample, the strength of the calcium triplet is unexpectedly high, clearly indicating that the main stellar population of Fornax is significantly more metal-rich than could be inferred from the position of its RGB in the CMD.
- ID:
- ivo://CDS.VizieR/J/A+A/389/787
- Title:
- VRI Photometry of Galaxies in AC118 Field
- Short Name:
- J/A+A/389/787
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present new photometric V-, R- and I-band data for the rich galaxy cluster AC118 at z=0.31. The new photometry covers an area of 8.6x8.6arcmin^2^, corresponding to 2.9x2.9Mpc^2^ (H_0_=50km/s/Mpc, q_0_=0.5 and Lambda=0). The data have been collected for a project aimed at studying galaxy evolution through the color-magnitude relation and the fundamental plane. We provide a catalogue including all the sources (N=1206) detected in the cluster field. The galaxy sample is complete to V=22.8mag (N_gal=574), R=22.3mag (N_gal=649) and I=20.8mag (N_gal=419). We give aperture magnitudes within a fixed aperture of 4.4arcsec and Kron magnitudes. We also give photometric redshifts for 459 sources for which additional U- and K-band photometry is available. We derive and discuss the V- and R-band luminosity functions. The catalogue is intended as a tool for studies in galaxy evolution.
- ID:
- ivo://CDS.VizieR/J/A+A/627/A135
- Title:
- VRI photometry of IC5070 variable stars
- Short Name:
- J/A+A/627/A135
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We observed a field of 16'x16' in the star-forming region Pelican Nebula (IC 5070) at BVRI wavelengths for 90 nights spread over one year in 2012-2013. More than 250 epochs in VRI-bands are used to identify and classify variables up to V~21mag. We present a catalogue of optical time-series photometry with periods, mean-magnitudes and classifications for 95 variable stars including 67 pre-main-sequence variables towards star-forming region IC 5070. The pre-main-sequence variables are further classified as candidate classical T Tauri and weak-line T Tauri stars based on their light curve variations and the locations on the color-color and color-magnitude diagrams using optical and infrared data together with Gaia DR2 astrometry. Classical T Tauri stars display variability amplitudes up to three times the maximum fluctuation in disk-free weak-line T Tauri stars, which show strong periodic variations. Short-term variability is missed in our photometry within single nights. Several classical T Tauri stars display long-lasting (>10 days) single or multiple fading and brightening events up to a couple of magnitudes at optical wavelengths.
- ID:
- ivo://CDS.VizieR/J/AJ/118/2409
- Title:
- VRI photometry of {lambda} Ori PMS stars
- Short Name:
- J/AJ/118/2409
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We have found 72 premain-sequence (PMS) stars near the center of the {lambda} Orionis star-forming region by spectroscopically testing a magnitude-limited sample for the presence of lithium {lambda}6708 absorption, a diagnostic of youth. All of these stars show large lithium equivalent widths and radial velocities consistent with Orion membership, but only two were discovered previously via H{alpha} or X-ray surveys.
- ID:
- ivo://CDS.VizieR/J/AJ/123/387
- Title:
- VRI photometry of {lambda} Ori star-forming region
- Short Name:
- J/AJ/123/387
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present VRI photometry of 320,917 stars with 11<~R<~18 throughout the {lambda} Ori star-forming region. Using the more spatially limited spectroscopic surveys of Dolan & Mathieu (1999, Cat. <J/AJ/118/2409>, 2001, Cat. <J/AJ/121/2124>) to define the color-magnitude domain of young low-mass members of the association and removing statistically the field stars in this domain, we use our photometry to identify a representative pre-main-sequence (PMS) population throughout the interior of the molecular ring.
5927. VRI photometry of M35
- ID:
- ivo://CDS.VizieR/J/ApJ/546/1006
- Title:
- VRI photometry of M35
- Short Name:
- J/ApJ/546/1006
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present very deep and accurate photometry of the open cluster M35. We have observed this association in the Cousins R, I filters, together with the Johnson V filter. We have covered a region of 27.5x27.5 square arcmin, equivalent to a fifth of the total area of the cluster. The data range from I_c_=12.5 to 23.5mag, and the color intervals are 0.4<=(V-I)_c_<=3.0, 0.5<=(R-I)_c_<=2.5. Roughly, these values span from 1.6M_{sun}_ down to the substellar limit, in the case of cluster members. By using the location of the stars on color-magnitude and color-color diagrams, we have selected candidate members of this cluster. We have merged our sample with previously published data and obtained a color-magnitude diagram for the complete stellar population of the cluster, covering the spectral range early B-mid M. Based on the distribution of field and cluster stars in color-magnitude and color-color diagrams, we estimate that two-thirds of these candidates are likely to be true members of M35. These stars approximately double the number of stars identified as candidate members of this cluster (~2700). We provide the photometry and accurate positions of these stars.
- ID:
- ivo://CDS.VizieR/J/AJ/120/1
- Title:
- VRI photometry of PDCS survey
- Short Name:
- J/AJ/120/1
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- This paper presents the COP (CFHT optical PDCS; CFHT: Canada-France-Hawaii Telescope, PDCS: Palomar Distant Cluster Survey) survey data. We describe our photometric and spectroscopic observations with the multiobject spectrograph (MOS) at the CFHT. A comparison of the photometry from the PDCS catalogs and from the new images we have obtained at the CFHT shows that the different magnitude systems can be cross-calibrated. After identification between the PDCS catalogs and our new images, we built catalogs with redshift, coordinates, and V_PDCS_, I_PDCS_, and R_COP_ magnitudes. We have classified the galaxies along the lines of sight into field and structure galaxies using a gap technique from Katgert et al. In total we have observed 18 significant structures along the 10 lines of sight.
- ID:
- ivo://CDS.VizieR/J/AJ/127/2228
- Title:
- VRI photometry of PMS stars in NGC 2264 OB
- Short Name:
- J/AJ/127/2228
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We summarize the results of an observing campaign to identify periodic pre-main-sequence (PMS) variables in the NGC 2264 OB association. We find 201 periodic candidates.
- ID:
- ivo://CDS.VizieR/J/MNRAS/369/697
- Title:
- VRI photometry of SMC/LMC globular clusters
- Short Name:
- J/MNRAS/369/697
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present accurate integrated-light photometry in Johnson/Cousins V, R and I for a sample of 28 globular clusters in the Magellanic Clouds. The majority of the clusters in our sample have reliable age and metallicity estimates available in the literature. The sample encompasses ages between 50Myr and 7Gyr, and metallicities ([Fe/H]) between 1.5 and 0.0dex. The sample is dominated by clusters of ages between roughly 0.5 and 2Gyr, an age range during which the bolometric luminosity of simple stellar populations is dominated by evolved red giant branch stars and thermally pulsing asymptotic giant branch (TP-AGB) stars whose theoretical colours are rather uncertain. The VRI colours presented in this paper have been used to calibrate stellar population synthesis model predictions.
