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Kinematics of the Central Regions of NGC 1672
We present two-dimensional spectroscopy and broad band imaging of theLINER galaxy NGC 1672. The velocity field and morphology of the central2kpc indicate higher mass concentration than in normal spirals, offsetsbetween the nuclear continuum baricenter and the kinematical center, andbetween both and the cente r of the bar. Satoh's model fit to thevelocity field reveals non-axisymmetric residuals, not well correlatedwith the bar or the circumnuclear ring of HII regions. The innerrotation curve locates the ring of star formation on an ILR, and notnear the peak of Ω-κ/{2}, as suggested by previous works,also claiming the ring rotating faster than its ambient, result notconfirmed h ere.
| Kinematics of the Central Regions of NGC 1672
We present the detailed velocity field of the central 2 kpc of the LINERgalaxy NGC 1672. The isovelocity map shows a rotational pattern with avelocity gradient of 50 km s^-1 arcsec^-1 in the inner 6" (1^''~70 pc),indicating a mass of ~9x10^8 M_solar inside a radius of 125 pc,equivalent to a density of ~2x10^11 M_solar kpc^-3. It also shows someasymmetries on a larger scale. An offset of ~60 pc between the nuclearcontinuum barycenter and the kinematical center is also found. Satoh'smodel fitting to the observed velocity field reveals severalnonaxisymmetric residuals, which do not correlate well with the bar orthe circumnuclear ring of H II regions. The inner rotation curve of NGC1672 reveals that the circumnuclear ring of star formation is located onan inner Lindblad resonance (ILR), and not near the peak of the Lindbladcurve, Omega-kappa/2, as suggested by previous works, which also claimedthat the ring rotates faster than its ambient. This motion is notconfirmed by the two-dimensional residual-velocity map.
| An image database. II. Catalogue between δ=-30deg and δ=70deg.
A preliminary list of 68.040 galaxies was built from extraction of35.841 digitized images of the Palomar Sky Survey (Paper I). For eachgalaxy, the basic parameters are obtained: coordinates, diameter, axisratio, total magnitude, position angle. On this preliminary list, weapply severe selection rules to get a catalog of 28.000 galaxies, wellidentified and well documented. For each parameter, a comparison is madewith standard measurements. The accuracy of the raw photometricparameters is quite good despite of the simplicity of the method.Without any local correction, the standard error on the total magnitudeis about 0.5 magnitude up to a total magnitude of B_T_=17. Significantsecondary effects are detected concerning the magnitudes: distance toplate center effect and air-mass effect.
| The CfA Redshift Survey: Data for the NGP +36 Zone
We have assembled redshifts for a complete sample of 719 galaxies withm_zw_ <= 15.5 in the declination range 32.5^deg^ <= δ <=38.5^deg^ and right ascension range 8^h^ <= α <= 17^h^. Wehave determined morphological types for all galaxies in the magnitudelimited sample by direct inspection of the POSS-O plates. 576 of theredshifts are measurements from Mount Hopkins, and 405 are newredshifts. We also include new redshifts for 77 fainter galaxies in thesame strip.
| 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.
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