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|Redshifts for 2410 Galaxies in the Century Survey Region|
The Century Survey strip covers 102 deg2 within the limits8h5<=α<=16h5, 29.0d<=δ<=30.0d, equinoxB1950.0. The strip passes through the Corona Borealis supercluster andthe outer region of the Coma cluster. Within the Century Survey region,we have measured 2410 redshifts that constitute four overlappingcomplete redshift surveys: (1) 1728 galaxies with Kron-CousinsRph<=16.13 covering the entire strip, (2) 507 galaxieswith Rph<=16.4 in right ascension range8h32m<=α<=10h45m, equinox B1950.0, (3) 1251 galaxies withabsorption- and K-corrected RCCDc<=16.2 (where ``c''indicates ``corrected'') covering the right ascension range8h5<=α<=13h5, equinox B1950.0, and (4) 1255 galaxieswith absorption- and K-corrected VCCDc<=16.7 also coveringthe right ascension range 8h5<=α<=13h5, equinoxB1950.0. All these redshift samples are more than 98% complete to thespecified magnitude limit. We derived samples 1 and 2 from scans of thePOSS1 red (E) plates calibrated with CCD photometry. We derived samples3 and 4 from deep V and R CCD images covering the entire region. Weinclude coarse morphological types for all the galaxies in sample 1. Thedistribution of (V-R)CCD for each type correspondsappropriately with the classification. Work reported here is basedpartly on observations obtained at the Michigan-Dartmouth-MITObservatory.
|V- and R-band Galaxy Luminosity Functions and Low Surface Brightness Galaxies in the Century Survey|
We use 64 deg2 of deep V and R CCD images to measure thelocal V- and R-band luminosity functions of galaxies. TheV0<16.7 and R0<16.2 redshift samples contain1255 and 1251 galaxies and are 98.1% and 98.2% complete, respectively.We apply k-corrections before the magnitude selection so that thecompleteness is to the same depth for all spectral types. The V and Rfaint-end slopes are surprisingly identical: α=-1.07+/-0.09.Representative Schechter function parameters for H0=100 are:M*R=-20.88+/-0.09,φ*R=0.016+/-0.003 Mpc-3 andM*V=-20.23+/-0.09,φ*V=0.020+/-0.003 Mpc-3. The V andR local luminosity densities,jR=(1.9+/-0.6)×108 Lsolar andjV=(2.2+/-0.7)×108 Lsolar, are inessential agreement with the recent 2 Degree Field Galaxy RedshiftSurvey and Sloan Digital Sky Survey determinations. All low surfacebrightness (LSB) galaxies fall in the large-scale structure delineatedby high surface brightness galaxies. The properties and surface numberdensity of our LSB galaxies are consistent with the LSB galaxy catalogof O'Neil, Bothun & Cornell, suggesting that our samples arecomplete for LSB galaxies to the magnitude limits. We measure colors,surface brightnesses, and luminosities for our samples, and find strongcorrelations among these galaxy properties. The color-surface brightnessrelation is(V-R)0=(-0.11+/-0.05)μR,0+(2.6+/-0.9).
|A Medium-deep Survey of a Minislice at the North Galactic Pole. II. The Data|
We report 328 redshifts, b_J_ magnitudes, and b_J_ - r_F_ colors ofgalaxies measured in a redshift survey of a 4^deg^ x 0.67^deg^ sliceclose to the north Galactic pole. The faintest galaxies in this surveyhave a magnitude of b_j_ ~ 20.5. The redshifts present external errorsof the order of 70 km s^-1^ and we estimate that the mean photometryerrors are ~0.2 for magnitudes and ~0.3 for colors. The redshiftcompleteness level of the sample is of the order of ~35% at b_J_ = 20,and part of this rather low completeness is the result of thecombination of limitations imposed by the multifiber system with theclustering of galaxies, and an insufficient number of configurations. Atthe nominal magnitude limit of the survey, we were able to measureredshifts for ~70% of the galaxies we observed. From the correlationbetween observed properties of the galaxies in this sample, wedemonstrate that the mean surface brightness is a major limiting factorin our ability to measure redshifts of faint objects.
|Automated surface photometry for the Coma Cluster galaxies: The catalog|
A homogeneous photometry catalog is presented for 450 galaxies withB25.5 less than or equal to 16 mag located in the 9.8 deg x9.8 deg region centered on the Coma Cluster. The catalog is based onphotographic photometry using an automated surface photometry softwarefor data reduction applied to B-band Schmidt plates. The catalogprovides accurate positions, isophotal and total magnitudes, major andminor axes, and a few other photometric parameters including rudimentarymorphology (early of late type).
|Galaxy Properties at the North Galactic Pole. I. Photometric Properties on Large Spatial Scales|
A two-color study of the galaxies detected on POSS-I in a 289 squaredegree region centered on the North Galactic Pole is presented. We use avariety of mapping techniques to characterize the large-scale spatialdistribution of galaxies. The depth and sample size of this new surveyallows, for the first time, the isolation of large photometricsubsamples of galaxies in high- and low-density environments on thescale of superclusters. Our principal finding is a statisticallysignificant difference between the mean photometric properties of thesesubsamples in the sense that galaxies in the high-density Coma andfilament environments have redder colors and larger concentrationindices than galaxies drawn from low-density interfilament regions.These results are in accord with the known morphology-density relation.Thus, appropriately chosen photometric and morphological parameters, inconcert with a galaxy surface density map, can be used to selectstructures from the projected galaxy distribution which correspond toregions of high density. An illustration of this point is our discoveryof a concentration of blue galaxies identified in our maps near the coreof the Coma cluster. This feature is comprised of early-type galaxieswhich exhibit signs of current or recent star formation. These resultsare predicated on relations between morphological type and photometricparameters derived from APS scans of POSS-I. We therefore discuss theimage calibration procedures used to compile our catalog of physicallysignificant photometric parameters. We demonstrate the morphologicaltype dependence among quantities such as mean color and imageconcentration index, and the lack of such a dependence for mean surfacebrightness.
|The Dynamics of the Outer Regions of the Coma Cluster|
We apply the spherical infall model to compare the observed distributionof radial velocities of galaxies around Coma with predictions that arebased on optical and X-ray overdensity profiles. Two optically selectedgalaxy catalogues, the CfA redshift survey and a UKST plate scanned withthe APM, are used to determine the overdensity profile of the cluster.The two sets of predicted caustics in the angular separation-redshiftdiagram are compared with a radial velocity catalogue which we haveextended significantly in the range between 10 and 40 from the centre ofthe Coma cluster. In total, we have measured 98 new redshifts. Despitealmost doubling the number of radial velocities in this interval, wefail to find the caustics with any degree of certainty. Using recentX-ray-based density profiles of Coma, we derive an independentprediction of the caustics in redshift space. The velocities predictedusing these X-ray profiles are in general agreement with the observedvelocity distribution. We also investigate the effect that non-sphericalmass distributions have on the velocity field in the halo. For avelocity field that is constant on concentric ellipsoids, we show thatthe caustics are blurred, providing a natural explanation of why we donot see the caustics in Coma.
|The Coma Cluster - Part One - a Catalogue of Magnitudes Colours Ellipticities and Position Angles for 6724 Galaxies in the Field of the Coma Cluster|
Abstract image available at:http://adsabs.harvard.edu/cgi-bin/nph-bib_query?1983MNRAS.202..113G&db_key=AST
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