- ID:
- ivo://CDS.VizieR/J/AJ/112/1061
- Title:
- BV photometry of NGC 7099
- Short Name:
- J/AJ/112/1061
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- New BV CCD photometry for the bright stars in cluster fields centered on the core of NGC 7099 is presented. The morphology of the LF though the turnoff region is similar to that found in other metal-poor clusters in that the relative number of turnoff to giant stars is lower than predicted by canonical models. Comparisons with evolutionary sequences of horizontal branch stars suggest a reddening E(B-V)=0.06 and a distance modulus (m-M)_V=14.83. Isochrone fits to [Fe/H]=-2.03, [O/Fe]=+0.70 models are consistent with an age of at least 14 Gyr. The model LF for this age accurately predicts the brightness of the tip of the red giant branch (RGB) as well as the location of the break which signals the transition from the base of the RGB to the main sequence. There is an indication that the evolutionary pause on the RGB, which manifests itself as a bump in the LF, occurs one magnitude fainter than the models predict. The excess of HB stars with respect to giants is confirmed and implies a helium abundance Y=0.28, which is higher than that found in other metal-poor globular clusters from the R method. From a comparison with the metal-rich, blue horizontal branch cluster NGC 288, it is argued that age cannot by itself be the solution to the second parameter problem.
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- ID:
- ivo://CDS.VizieR/J/AJ/97/1360
- Title:
- BV photometry of Palomar 12
- Short Name:
- J/AJ/97/1360
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present broadband B,V photometry for 1154 stars in the field of the Galactic globular cluster Palomar 12, based upon direct CCD images obtained with the Canada-France-Hawaii 3.6m and Cerro Tololo 4m telescopes. The overall zero points of our V magnitudes and B-V colors appear to be known to about +/-0.02mag and +/-0.01mag, and our magnitude- and color-scale errors are probably controlled to <0.01mag. Pal 12's main sequence shows an excess fringe of stars along its red edge which are probably binaries; the CM diagram also contains a small number of probable blue stragglers. The principal result of this paper is that the color-magnitude diagram of Pal 12 is anomalous, in the sense that we cannot fake all of its principal sequences lie near or between those of the well studied and presumably typical Galactic globular clusters 47 Tucanae and M5, even though it lies near or between them in overall heavy-element abundance. The simplest explanation is that Pal 12 is younger than the other two clusters by some 25-30%. Other explanations are also possible, although perhaps somewhat harder to believe. This result greatly strengthens the possibility that age differences are responsible, at least in part, for the anomalous properties of some of the outer-halo globular clusters. Spectroscopic indications are that Pal 12's chemical abundances should also strongly resemble those of the two Galactic globular clusters NGC 288 and NGC 362, which have also been claimed to show age differences in comparison with M5. However, attempts to derive ages for these clusters relative to M5 and Pal 12 are inconclusive, possibly due to some inconsistencies within the available data.
- ID:
- ivo://CDS.VizieR/J/A+AS/122/1
- Title:
- BV photometry of variables in NGC 6397
- Short Name:
- J/A+AS/122/1
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- Tables 5 and 6 contain BV photometry of stars from NGC 6397 field which is presented in Figs. 1 and 2, respectively. File template.fits is a FITS format image of the surveyed field. Stars coordinates listed in the paper correspond to positions on this image.
- ID:
- ivo://CDS.VizieR/J/MNRAS/385/361
- Title:
- BVRcIc photometry of NGC 821 globular clusters
- Short Name:
- J/MNRAS/385/361
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We performed a photometric study of globular clusters around the isolated elliptical galaxy NGC 821. B, V and R-band photometry come from the Mini-Mosaic imager on the 3.5-m Wisconsin Indiana Yale NOAO (WIYN) telescope. Observations were conducted between November 30 - December 2, 2005. Average seeing conditions were ~0.7". Two Hubble Space Telescope (HST) Wide-Field Planetary Camera 2 (WFPC2) fields were analysed in the V and I-bands. Objects in this catalogue are the globular cluster candidates according to the selection criteria detailed in the journal article. Astrometric solution is from USNO-B stars. Note the center of NGC 821 on this system is located at 02:08:21.118 +10:59:42.21. Photometry has been corrected for Galactic extinction and we used a distance modulus of m-M=31.75 in our analysis.
- ID:
- ivo://CDS.VizieR/J/A+A/317/448
- Title:
- BVRHalpha photometry of NGC 1818
- Short Name:
- J/A+A/317/448
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present B,V,R,Halpha CCD photometry and astrometry of Be stars in NGC 1818, its small neighbouring cluster NGC 1818B, and the surrounding field down to V = 18 mag. Our Be star identifiers conform to IAU specifications. For a description of the UBVRI and Halpha systems, see e.g. <GCPD/08> and <GCPD/55>
- ID:
- ivo://CDS.VizieR/J/AJ/107/230
- Title:
- BVRI CCD photometry of NGC 1904
- Short Name:
- J/AJ/107/230
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present BVRI photometry of three overlapping fields in the globular cluster NGC 1904 (M79), observed with a CCD camera and the 2.2m Max-Planck-Institute telescope at ESO/La Silla. We critically compare our photometry using the INVENTORY data reduction code with results derived by other investigators using different codes. These comparisons convince us that all modern codes give results reliable to at least +/-0.3mag at all levels, as long as the fields are not overly crowded. Specifically, our results for NGC 1904 (M79) are as follows: V(TO)=19.60+/-0.10 (estimated external error), with turnoff colors at B-V=0.40, V-R=0.27, V-I=0.57, and B-I=0.97, all with estimated external errors of +/-0.06. By fitting the four resulting ridge lines to the theoretical isochrones of VandenBerg & Bell [ApJS, 58, 561 (1985)] interpolated to [Fe/H]=-1.60, Y=0.20, and [O/Fe]=0.00, we derive an average value for the age of 16Gyr, where we have adopted E(B-V)=0.01.
- ID:
- ivo://CDS.VizieR/J/AJ/145/165
- Title:
- BVRI photometry in NGC 6496
- Short Name:
- J/AJ/145/165
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present high-quality BVRI photometric data in the field of globular cluster NGC6496 obtained with the SOAR Telescope Adaptive Module (SAM). Our observations were collected as part of the ongoing SAM commissioning. The distance modulus and cluster color excess as found from the red clump are (m-M)_V_=15.71+/-0.02mag and E(V-I)=0.28+/-0.02mag. An age of 10.5+/-0.5Gyr is determined from the difference in magnitude between the red clump and the subgiant branch. These parameters are in excellent agreement with the values derived from isochrone fitting. From the color-magnitude diagram we find a metallicity of [Fe/H]=-0.65dex and hence support a disk classification for NGC 6496. The complete BVRI data set for NGC6469 is made available in the electronic edition of the Journal.
- ID:
- ivo://CDS.VizieR/J/PASP/117/1325
- Title:
- BVRI photometry in NGC4147
- Short Name:
- J/PASP/117/1325
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- New BVRI broadband photometry and astrometry are presented for the globular cluster NGC 4147, based upon measurements derived from 524 ground-based CCD images mostly either donated by colleagues or retrieved from public archives. We have also reanalyzed five exposures of the cluster obtained with WFPC2 on the Hubble Space Telescope in the F439W and F555W (B and V) filters.
- ID:
- ivo://CDS.VizieR/J/PASP/117/37
- Title:
- BVRI photometry in NGC 2419, Pal 4, and Pal 14
- Short Name:
- J/PASP/117/37
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- The results from work done to extend the Johnson-Cousins BVRI photometric standard sequence to faint levels of V~21mag in compact fields is presented. Such calibration and extension of sequences is necessary to fill a calibration gap if reliable photometry from modest aperture telescopes in space (e.g., the Hubble Space Telescope) or terrestrial telescopes with apertures exceeding 4m is to be done. Sequences like the ones presented here, which cover a large range in brightness as well as color, will allow photometric calibration to be done efficiently and will also make such work less prone to systematic sources of error. Photometry of stars in approximately 10'x10' fields around three globular clusters (NGC 2419, Pal 4, and Pal 14) are presented from data acquired over several photometric nights. In each field, several stars are measured in B, V, R, and I passbands, with standard errors in the mean less than 0.015mag from random errors, to levels fainter than V=21mag.
- ID:
- ivo://CDS.VizieR/J/A+AS/115/297
- Title:
- BVRI photometry of Central Field of {omega} Cen
- Short Name:
- J/A+AS/115/297
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- This is a four colour photometric study of stars in the central part of the globular cluster {omega} Centauri. The observations were made at Siding Spring Observatory in April 1992 with the 1m ANU telesecope; a 1024x1024CCD has been used. The photometry was reduced to the BVRI system using standards by Landolt
