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|Supernova 2004ch in NGC 5612|
R. Martin, Perth Observatory, reports the discovery of an apparentsupernova (red mag about 16) found on CCD images taken on May 12.619 andJune 1.431 UT with the 0.61-m Perth/Lowell Automated Telescope in thecourse of the Perth Automated Supernova Search. SN 2004ch is located atR.A. = 14h34m06s.27, Decl. = -78o23'09".5 (equinox 2000.0; uncertainty+/- 0".15 in each coordinate), which is 62".5 east and 8".0 north of thecenter of NGC 5612. Nothing was visible at this location on an imagetaken on May 12.619 (limiting mag 19).
|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.
|The Catalog of Southern Ringed Galaxies|
The Catalog of Southern Ringed Galaxies (CSRG) is a comprehensivecompilation of diameters, axis ratios, relative bar position angles, andmorphologies of inner and outer rings, pseudorings, and lenses in 3692galaxies south of declination -17 deg. The purpose of the catalog is toevaluate the idea that these ring phenomena are related to orbitalresonances with a bar or oval in galaxy potentials. The catalog is basedon visual inspection of most of the 606 fields of the Science ResearchCouncil (SRC) IIIa-J southern sky survey, with the ESO-B, ESO-R, andPalomar Sky surveys used as auxiliaries when needed for overexposed coreregions. The catalog is most complete for SRC fields 1-303 (mostly southof declination -42 deg). In addition to ringed galaxies, a list of 859mostly nonringed galaxies intended for comparison with other catalogs isprovided. Other findings from the CSRG that are not based on statisticsare the identification of intrinsic bar/ring misalignment; bars whichunderfill inner rings; dimpling of R'1pseudorings; pointy, rectangular, or hexagonal inner or outer ringshapes; a peculiar polar-ring-related system; and other extreme examplesof spiral structure and ring morphology.
|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 supergalactic plane redshift survey|
Redshift measurements, about 1000 of which are new, are presented for1314 galaxies in a survey toward the apex of the large-scale streamingflow for ellipticals. The velocity histogram shows that the excess ingalaxy number counts in this area is due to a substantial concentrationof galaxies with discrete peaks at V about 3000 km/s and V about 4500km/s. After correction for the sampling function, the centroid of thedensity distribution is found to be near V about 4500 km/s.Normalization to the more extensive SSRS survey, which was selected bythe same criteria, shows that the region studied contains a considerableoverdensity of galaxies from 2000 to 6000 km/s. This result is in goodagreement with the 'great attractor' model suggested by Lynden-Bell etal. (1988) which attributes the peculiar motions of elliptical galaxiesover a large region of space to an extensive mass overdensity whichincludes the Hydra-Centaurus and Pavo-Indus superclusters. The centroidof the density enhancement is also consistent with new data by Dresslerand Faber (1990) of peculiar motions of elliptical and spiral galaxies,both of which show a zero crossing of the Hubble line at approximately4500-5000 km/s.
|Triaxiality in disk galaxies|
Thirty-two bulges of nearby spirals have been observed, to detectmisalignment between disk and bulge apparent major axes. Suchmisalignment is unequivocally present in the majority of observedobjects. This may be due to the triaxiality of disks, bulges, or both.The probability distribution function for the axial ratios is derivedunder the two extreme hypotheses, i.e., that either only disks (case I)or only bulges (case II) are triaxial: the observational data areequally well fitted by either one. Since dynamical evidence and theinternal twisting of isophotes show that bulges are triaxial, case I isunlikely, but an intermediate case cannot be ruled out. Thesedistribution functions are compared with available constraints; inparticular, that of case II is projected and compared with thedistribution of apparent ellipticities of minor-axis dust-laneellipticals and of all ellipticals. Both tests show that the observedand derived distributions are consistent.
|The stellar-free emission component in galactic nuclei - At low-levels, evidence for shock ionization|
The emission-line component in a sample of 92 galaxies was isolatedusing stellar absorption templates built from emission-free star clusterspectra and taking into account all sources of reddening extrinsic tothe line emitting regions, and the emission line properties werestatistically analyzed. Three characteristic average spectra were built,including those corresponding to nuclear H II regions, objectsidentified as LINERs, and extreme low-level emission galaxies with W(em)of not greater than 2 A. For the latter, line measurements were pusheddown to very low level. The measurements of the ratio between forbiddenS II line and forbidden S III line indicate that, in the extremelow-level emission galaxies, the shock ionization is the mechanism atwork.
|Population synthesis in galactic nuclei using a library of star clusters|
A novel galactic-nucleus population-synthesis technique is described anddemonstrated. The procedure is applicable to normal nuclei of E/S0 andspiral galaxies and employs a data base of integrated star-clusterspectra, thus reducing the number of parameters in the analysis to two(age and metallicity), as proposed by Bica and Alloin (1986). Resultsare presented in extensive tables and spectra and discussed in detail.The populations in the E/S0s with normal metallicity/luminosityrelations are found to comprise mainly stars older than 10 Gyr, withsome as young as about 5 Gyr; younger groups are superimposed on older,solar-metallicity populations in the bluer spirals. In NGC 5236, forexample, 87 and 57 percent of the flux at 400 and 900 nm, respectively,is attributed to stars younger than about 300 Myr.
|Analysis of absorption-line spectra in a sample of 164 galactic nuclei|
Spectral observations in the 3700-8000 A range of 154 normal galacticnuclei, two amorphous galaxies, and eight intrinsically faint activenuclei whose visible spectrum is dominated by the stellar component arediscussed. A typical red, strong-lined spectrum is found for each groupfrom E to Sb in the -23.2 to -19.0 luminosity range, as well as for thevery luminous Sbc and Sc galaxies, although a few atypical nucleiexhibit variable contents of bluer stellar components. No prototype canbe assigned to the Sbc and Sc galaxies in the -21.9 to -19.0 luminosityrange. Analysis of the equivalent widths shows that the CN 4216-4250 Afeature has the largest dynamical range as a function of metallicity. Itis suggested that young stars are responsible for the blue colors inNGC2865, 4382, and 5102, and that metal-poor stars do not contributesignificantly.
|A catalogue of early-type galaxies with emission lines|
Spectroscopic and photometric data on 289 early-type galaxies (E and S0)with optical emission lines are presented and possible correlationsamong properties of the galaxies in the sample are investigated. Theoccurrence of phenomena as radio emission, presence of neutral hydrogenand dust shows an increase in comparison with the occurrence of the samephenomena in these morphological classes as a whole. There is noevidence of a relationship between apparent shape and presence ofionized gas in the central regions.
|Near-infrared spectral properties of star clusters and galactic nuclei|
A powerful method for the correction of CCD fringes in the near-IR ispresented, together with 6300-9700 A CCD spectra of 30 star clusterscovering the 1 million to 16.5 billion age range and observations of 62galactic nuclei in galaxies of E to Sc morphological type. An analysisof the star cluster sample indicates that, in the near-IR spectralrange, metallicity is the dominant parameter. Attention is given to thesecond-order effects produced by age. Grid predictions as a function ofmetallicity and age are given for five metallic features and for thecontinuum distribution.
|Study of a complete sample of galaxies. II - Spectroscopy of the nuclei|
Spectroscopic observations of a complete sample of 320 galaxies (fromthe Revised Shapley Ames Catalog of Sandage and Tammann, 1981) withdeclination less than or equal to +20 deg, galactocentric velocity lessthan 3000 km/s, and absolute magnitude brighter than M(B) = -21.0 arereported. The 400-700-nm spectra were obtained with resolution about 1nm using the Boller and Chivens spectrograph and image-dissector scannerat the Cassegrain focus of the 1.52-m telescope at ESO on 36 nightsduring 1980-1983. The data are presented in extensive tables and spectraand briefly characterized. The majority of the spectra are classified asH II regions ionized by hot stars or as Seyfert-like nebulosities.
|Southern Galaxy Catalogue.|
|A survey of O II forbidden line emission in elliptical galaxies|
A survey of elliptical galaxy spectra using image-tube spectrograms hasbeen carried out with the result that 40 percent of the galaxies havebeen found to contain ionized gas. Galaxies with intense nuclearemission also tend to have extended emission that appears to be confinedto a plane. Since there is a detectable velocity gradient for the gas inthose planes, the gas appears to be in a rotating disk.
|UBV photometry of 262 southern galaxies|
Multiaperture photometry of 262 bright southern galaxies in the JohnsonUBV system is given. Most of these are south of -30 deg declination,although some northward to -10 deg are included. A total of 169 objectshave published radial-velocity determinations. These provide distancesand enable construction of color-magnitude diagrams for this subset ofobjects through a physical diameter of 2.0 kpc (with H = 100). Thetwo-color diagrams for the inner regions of the galaxies differ fromthose of integrated galaxies due to the color changes towards theircenters. Comparison with theoretical models of Larson and Tinsley (1978)suggest that the colors of the inner portions of most ellipticals andlenticulars are consistent with their having all stars formed at nearlyone epoch with little subsequent star formation, while for spiralslarger amounts of star formation, either in bursts or continuously, aresuggested. This simple picture is complicated by the presence of certainobjects having peculiar colors indicative of large amounts of recentstar formation.
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