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Arcsecond Positions of UGC Galaxies
We present accurate B1950 and J2000 positions for all confirmed galaxiesin the Uppsala General Catalog (UGC). The positions were measuredvisually from Digitized Sky Survey images with rms uncertaintiesσ<=[(1.2")2+(θ/100)2]1/2,where θ is the major-axis diameter. We compared each galaxymeasured with the original UGC description to ensure high reliability.The full position list is available in the electronic version only.
| Total magnitude, radius, colour indices, colour gradients and photometric type of galaxies
We present a catalogue of aperture photometry of galaxies, in UBVRI,assembled from three different origins: (i) an update of the catalogueof Buta et al. (1995) (ii) published photometric profiles and (iii)aperture photometry performed on CCD images. We explored different setsof growth curves to fit these data: (i) The Sersic law, (ii) The net ofgrowth curves used for the preparation of the RC3 and (iii) A linearinterpolation between the de Vaucouleurs (r(1/4) ) and exponential laws.Finally we adopted the latter solution. Fitting these growth curves, wederive (1) the total magnitude, (2) the effective radius, (3) the colourindices and (4) gradients and (5) the photometric type of 5169 galaxies.The photometric type is defined to statistically match the revisedmorphologic type and parametrizes the shape of the growth curve. It iscoded from -9, for very concentrated galaxies, to +10, for diffusegalaxies. Based in part on observations collected at the Haute-ProvenceObservatory.
| Integrated photoelectric magnitudes and color indices of bright galaxies in the Johnson UBV system
The photoelectric total magnitudes and color indices published in theThird Reference Catalogue of Bright Galaxies (RC3) are based on ananalysis of approximately equals 26,000 B, 25,000 B-V, and 17,000 U-Bmultiaperture measurements available up to mid 1987 from nearly 350sources. This paper provides the full details of the analysis andestimates of internal and external errors in the parameters. Thederivation of the parameters is based on techniques described by theVaucouleurs & Corwin (1977) whereby photoelectric multiaperture dataare fitted by mean Hubble-type-dependent curves which describe theintegral of the B-band flux and the typical B-V and U-B integrated colorgradients. A sophisticated analysis of the residuals of thesemeasurements from the curves was made to allow for the random andsystematic errors that effect such data. The result is a homogeneous setof total magnitudes BTA total colors(B-V)T and (U-B)T, and effective colors(B-V)e and (U-B)e for more than 3000 brightgalaxies in RC3.
| The nature of elongated ellipticals
We have analyzed the isophotal shapes of a sample of 63 elongatedelliptical galaxies, previously classified E4, 5, 6 or 7. We sorted themaccording to their isophotal class, defined by the type of deviationsfrom perfectly elliptical isophotal contours. These deviations areexpected to appear clearly, because of the very favorable orientation ofthese galaxies. We find the following results, after exclusion of 6non-elliptical galaxies: A large percentage (56%) of elongated E's aredisky objects with pointed isophotes, while only 35% have either boxy orirregular isophotes, in equal proportions, and the remaining 6 galaxies(10%) are diffucult to classify. Furthermore, 38% of disky Es's alsoshow slightly boxy spheroids. In almost all the galaxies of the sample,there is an angular range where the deviations are of the disk-type. Thefour galaxies not showing this effect are among the roundest ones in thesample, which suggests that projection effects hide detailed structuresof this kind in many ellipticals. The correlations already reported inthe literature between isophotal class and radio, X-ray emission andkinematical behavior are confirmed. In particular, there is a clear-cutcorrelation between velocity anisotropy and isophotal shape. The mostelongated Hubble types tend to be disky E's. Boxy/irregular E's rarelyexceed ellipticities of 0.45 while the maximum ellipticity of half ofthe disky Es's exceeds this value. These results confirm the dichotomyof E's, which fall roughly into two classes, disky and boxy/irregularellipticals. They also show a physical continuity between disky E's andSO's and suggest that the Hubble types are strongly correlated withdisk-to-bulge ratios throughout the Hubble sequence, even at itsearly-type end (round E's), for which the disk is hidden by orientationeffects Galaxies escaping the correlations are the boxy/irregular Es's,resulting probably from strong merging processes.
| Isophotal shapes of early-type galaxies. I - Elongated ellipticals
Forty-three very elongated elliptical galaxies were observed in directB, V, R CCD imaging with the 2-m telescope of Pic-du-Midi Observatoryand with the Canada-France-Hawaii telescope in fairly good seeingconditions. Five galaxies do not show an elliptical structure: threeclearly show spiral features and one is a dumbbell. The 38 othergalaxies were analyzed with an isophote-fitting procedure which allowsone to derive the deviations from pure ellipses in terms of thecoefficients of a Fourier series. The geometrical parameters of these 38elongated ellipticals are presented, with brief comments on theirpeculiarities.
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