The Photometric and Geometric Parameters of Galaxies in Clusters A 1983, 2065

We report the first results of a long term program aimed at investigating the photometric properties of the cores of Abell and X-ray selected (EMSS, Gioia et al. 1990) clusters of galaxies. We observed 77 clusters of galaxies in the redshift range 0.05 ≤ z ≤ 0.25 in the Gunn g, r and i filters: in this paper we present the data on 59 clusters with good absolute photometry and on another group of 8 clusters with acceptable relative photometry. For all these clusters we show color-magnitude diagrams in the two colors: when, as in most cases, the early type galaxy sequence is identifiable, we compare it with the expectation from the Virgo c-m relation and find that the Virgo relation holds to z ∼ 0.2. We do not find any sign of active evolution in cluster galaxies since that epoch, nor in the percentage of blue galaxies or in the early type galaxy colors, if we accept that the scatter is of the order of 0.2-0.3 mag with respect to the expectations on the basis of standard k-corrections. We point out the presence of a certain number of anomalously red galaxies in the r − i color, which are too red with respect to their g − r color to be normal field galaxies at a redshift higher than the cluster one. Finally we briefly compare a few properties of the two subsamples of optically selected and X-ray selected clusters.

The Astrophysical Journal Supplement Series, 2002

We carried out a deep photometric and spectroscopic survey of wide areas in the Coma cluster, aiming to investigate the properties of galaxy population in different environments within the cluster. We present the results in a series of papers. This paper, the first of the series, describes the imaging observations and photometric data reduction. Imaging data were taken with the wide-field mosaic CCD camera, which was attached to the prime focus of the 4.2 m William Herschel Telescope at La Palma, Canary Islands. Our observations covered a large field of view (2.22 deg 2 ) from the cluster center to the outskirts, and our photometry is complete to a limiting magnitude of R ' 23 mag. The limit of secure star-galaxy discrimination is, however, brighter at R ¼ 20 mag. We identified 3147 galaxies down to this limit in the part (1.32 deg 2 ) of the survey area, together with 662 galaxies identified in the control field SA 57. We measured surface photometric parameters and compiled a photometric catalog for these galaxies. Statistical properties of the catalog are shown in this paper, while the catalog itself is given in a forthcoming paper in the series.

Astrophysics, 1989

The results of two-color photometry of the rich cluster of galaxies A2256 in the B and V color system are presented. About 500 galaxies have been identified on the large scale plates of the 2.6-m telescope of the Byurakan Observatory up to approximately 21~8 in B. The luminosity function is constructed in both B and V colors. It has a usual form with the characteristic break at M~ =-19.0 and M~ =-19.9. The projected radial distribution of the number of galaxies and of surface luminosity have a steep density gradient. The luminosity and color segregation effects as well as the distribution of apparent ellipticities and position angles of the major axes of the galaxies have been investigated.

The Astrophysical Journal Supplement Series, 2004

Photometric observations are presented for 8747 galaxies in the fields of 28 clusters with redshifts in the range 0:05 < z < 0:11 and spanning a wide range in Abell richness class. The primary motivation for this study is to provide a nearby sample of clusters whose galaxy populations can be used to provide an anchor point for evolutionary studies of cluster galaxy populations. The present analysis focuses on the sequence of luminous red galaxies that form a tight correlation in the colormagnitude plane. An ensemble cluster constructed from the full sample shows the red sequence clearly and the observed dispersion-not corrected for observational errors-is (V À I) ¼ 0:071 AE 0:006 down to M I(AB) ¼ À19:5. Selecting only early-type galaxies on the basis of their fractional bulge luminosity (B=T) reduces the observed dispersion to (V À I) ¼ 0:050 AE 0:006 mag, a significantly smaller dispersion than the full sample at more than the 95% confidence level. The slope of the color-magnitude relation in (V À I)=I is À0:023 AE 0:006. This set of clusters shows a red sequence that has the same mean color in all clusters (V À I) AB ¼ 0:91 AE 0:03 (measured at M I(AB) ¼ À23) and has the same intrinsic dispersion, (V À I) ¼ 0:04 AE 0:01, in all clusters within the observational errors. Thus, these clusters form a remarkably homogeneous family as represented by their luminous red galaxy populations.

Monthly Notices of the Royal Astronomical Society, 2012

We present BV R c I c CCD photometry in the fields of six Galactic open clusters toward the Perseus spiral arm. These data, complemented with J, H, and K S magnitudes from 2MASS, have been used to determine the ages, distances, and colour excesses E(B − V) for these clusters: 40 Myr, 3180 +440 −380 pc, 0.54 ± 0.03 mag (Berkeley 96); 250 Myr, 2410 +220 −200 pc, 0.77±0.06 mag (Berkeley 97); 70 Myr, 2490 +180 −170 pc, 0.51±0.05 mag (King 12); 160 Myr, 2830 +160 −150 pc, 0.88 ± 0.09 mag (NGC 7261); 280 Myr, 2450 +190 −170 pc, 0.24 ± 0.03 mag (NGC 7296); and 160 Myr, 2750 +220 −210 pc, 0.49 ± 0.02 mag (NGC 7788). We found gaps in the mass function of clusters Be 97, King 12, and NGC 7788 in the mass intervals of [1.3-1.5], [1.4-1.6], and [1.5-1.7] solar masses, respectively.

The Astronomical Journal, 2005

We analyze photometric properties of 1384 cluster galaxies as a function of the normalized distance to cluster center. These galaxies were selected in the central region (r/r 200 ≤ 0.8) of 14 southern Abell clusters chosen from the Southern Abell Cluster Redshifts Survey (SARS). For 507 of these galaxies we also obtained their luminosity profiles. We have studied the morphology-clustercentric distance relation on the basis of the shape parameter n of the Sérsic's law. We also have

Astronomy & Astrophysics, 2002

Integrated UBV RI photometric parameters of 140 galactic open clusters have been computed. Integrated I(V − R)0 and I(V − I)0 colours as well as integrated parameters for 71 star clusters have been obtained for the first time. These, in combination with published data, altogether 352 objects, are used to study the integrated photometric characteristics of the galactic open clusters. The I(MV ) values range from −9.0 to −1.0 mag corresponding to a range in total mass of the star clusters from ∼25 to 4×10 4 M . The integrated colours have a relatively narrow range, e.g., I(B − V )0 varies from −0.4 to 1.2 mag.

1998

I would first and foremost like to thank my supervisor. Dr. John Lucey, for all his support, encouragement and patience over the past five years. The past year has been pretty stressful as I have struggled with holding down a full-time job and completing this thesis -John's comments and suggestions regarding the thesis have always been very helpful and much appreciated. I'd also like to thank the colleagues which I have collaborated with on various projects over the past years, including Rafael Guzman, Russell Smith, Mike Hudson and Roger Davies. The STARLINK computing facilities at Durham have improved continuously during my time here, and I thank Alan Lotts for his vital work maintaining the system which we all rely on. An important part of thesis has been the measurement of surface photometry, and I'd like to thank Marjin Franx for his permission to use the GALPHOT ellipse-fitting program. I acknowledge the support given to me by a SERC/PPARC studentship during my first three years in Durham. A special thanks goes to all the colleagues who have had the grave misfortune of sharing an office with me! I hope I've remembered everyone:

Il Nuovo Cimento C, 1992

S u m m a r y .-We present a complete database of photoelectric and photographic multiaperture photoelectric photometry of galaxies. The database contains all data published prior to 1991, in all standard photometric bands from UV to IR. The database contains also some global quantities as, for instance, total magnitudes and color indexes.

Monthly Notices of the Royal Astronomical Society, 2005

CCD BV I photometry is presented for 8 previously unstudied star clusters located in the First and Fourth Galactic Quadrants: AL 1, BH 150, NGC 5764, Lynga 9, Czernik 37, BH 261, Berkeley 80 and King 25. Color magnitude diagrams of the cluster regions suggest that several of them (BH 150, Lynga 9, Czernik 37 and BH 261 and King 25) are so embedded in the dense stellar population toward the galactic center that their properties, or even their existence as physical systems, cannot be confirmed. Lynga 9, BH 261 and King 25 appear to be slight enhancements of dense star fields, BH 150 is probably just a single bright star in a dense field, and Czernik 37 may be a sparse, but real cluster superimposed on the galactic bulge population. We derive preliminary estimates of the physical parameters for the remaining clusters. AL 1 appears to be an intermediate age cluster beyond the solar circle on the far side of the galaxy and the final two clusters, NGC 5764 and Berkeley 80 are also of intermediate age but located inside the solar ring. This set of clusters highlights the difficulties inherent in studying the stellar populations toward the inner regions of the galaxy.