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|Report on CCD activities at the Bronberg Observatory (CBA Pretoria) in 2005.|
|Supernova 2005cu in NGC 6754|
IAUC 8565 available at Central Bureau for Astronomical Telegrams.
|Supernova 2005cu in NGC 6754|
IAUC 8562 available at Central Bureau for Astronomical Telegrams.
|Infrared mergers and infrared quasi-stellar objects with galactic winds - II. NGC5514: two extranuclear starbursts with LINER properties and a supergiant bubble in the rupture phase|
A study of the morphology, kinematics and ionization structure of theinfrared (IR) merger NGC5514 is presented. This study is based mainly onINTEGRAL two-dimensional (2D) spectroscopy (obtained at the 4.2-mWilliam Herschel Telescope, WHT), plus optical and near-IR images. Clearevidence of two extranuclear starbursts with young outflows (OFs) andlow-ionization nuclear emission region (LINER) activity are reported.One of these OFs has generated a supergiant bubble and the other isassociated with an extended complex of HII regions.In the galactic bubble it was found that: (i) the [SII], Hα,[NII], [OI] and [OIII] emission-line maps show a bubble with a distortedellipsoidal shape, with major and minor axes of ~6.5 kpc [13.6 arcsec;at position angle (PA) = 120°+/- 10°] and ~4.5 kpc (9.6 arcsec);(ii) these maps depict four main knots, a very strong one and threeothers more compact and located at the border; (iii) the centre of thebubble is located at ~4.1 kpc (8.5 arcsec) to the west of the mainnucleus; (iv) the WHT spectra show, in this area, two strong components:blue and red emission-line systems, probably associated with emissionfrom the near and far side of the external shell, for which the mean OFvelocities were measured as VOFblue= (-320 +/- 20)kms-1 and VOFred= (+265 +/- 25) kms-1(v) these two components depict LINER properties, probably associatedwith large-scale OF + shocks; (vi) at the east border, the kinematics ofthe ionized gas and the [SII] emission-line maps show an extendedejection of 4 kpc aligned with the PA of the major axis; (vii) threeother ejections were found, two of them perpendicular to the extendedone. Each ejection starts in one of the knots. These results suggestthat the bubble is in the rupture phase.For the complex of giant HII regions it was found that: (i) theHα, [NII] and [SII] emission-line maps show a compact strongemission area (peaking at ~810 pc ~1.7 arcsec, to the east of the secondnucleus) and faint extended emission with an elongated shape, and majorand minor axes of ~5.1 kpc (10.8 arcsec; at PA ~20°) and ~2.9 kpc(6.0 arcsec); (ii) inside this complex, the spectra show HII region andtransition LINER/HII characteristics; (iii) at the border of thisextended HII area the spectra have outflow components and LINERproperties.INTEGRAL 2D [NII], Hα, [SII] and [OIII] velocity fields (VFs) arepresented. These VF maps show results consistent with an expansion ofthe bubble, plus four ejections of ionized gas. The U, B, V, I, J, H andKS images show a pre-merger morphology, from which faintfilaments of emission emerge, centred on the bubble. The ionizationstructure and the physical conditions were analysed using the following2D emission-line ratio and width maps: [SII]/Hα, [NII]/Hα,[OI]/Hα, [OIII]/Hβ and FWHM-[NII]. In the region of thebubble, 100 per cent of the [NII]/Hα and [SII]/Hα ratiosshow very high values (>0.8) consistent with LINER processesassociated with high-velocity shocks. These new results support theprevious proposition that extreme nuclear and `extranuclear' starburstswith galactic winds + shocks play an important role in the evolution ofIR mergers/quasi-stellar objects.
|Circumnuclear Structure and Black Hole Fueling: Hubble Space Telescope NICMOS Imaging of 250 Active and Normal Galaxies|
Why are the nuclei of some galaxies more active than others? If mostgalaxies harbor a central massive black hole, the main difference isprobably in how well it is fueled by its surroundings. We investigatethe hypothesis that such a difference can be seen in the detailedcircumnuclear morphologies of galaxies using several quantitativelydefined features, including bars, isophotal twists, boxy and diskyisophotes, and strong nonaxisymmetric features in unsharp-masked images.These diagnostics are applied to 250 high-resolution images of galaxycenters obtained in the near-infrared with NICMOS on the Hubble SpaceTelescope. To guard against the influence of possible biases andselection effects, we have carefully matched samples of Seyfert 1,Seyfert 2, LINER, starburst, and normal galaxies in their basicproperties, taking particular care to ensure that each was observed witha similar average scale (10-15 pc pixel-1). Severalmorphological differences among our five different spectroscopicclassifications emerge from the analysis. The H II/starburst galaxiesshow the strongest deviations from smooth elliptical isophotes, whilethe normal galaxies and LINERs have the least disturbed morphology. TheSeyfert 2s have significantly more twisted isophotes than any othercategory, and the early-type Seyfert 2s are significantly more disturbedthan the early-type Seyfert 1s. The morphological differences betweenSeyfert 1s and Seyfert 2s suggest that more is at work than simply theviewing angle of the central engine. They may correspond to differentevolutionary stages.
|Near-Infrared Spectra of Type Ia Supernovae|
We report near-infrared (NIR) spectroscopic observations of 12``branch-normal'' Type Ia supernovae (SNe Ia) that cover the wavelengthregion from 0.8 to 2.5 μm. Our sample more than doubles the number ofSNe Ia with published NIR spectra within 3 weeks of maximum light. Theepochs of observation range from 13 days before maximum light to 18 daysafter maximum light. A detailed model for a Type Ia supernovae is usedto identify spectral features. The Doppler shifts of lines are measuredto obtain the velocity and thus the radial distribution of elements. TheNIR is an extremely useful tool to probe the chemical structure in thelayers of SNe Ia ejecta. This wavelength region is optimal for examiningcertain products of the SNe Ia explosion that may be blended or obscuredin other spectral regions. We identify spectral features from Mg II, CaII, Si II, Fe II, Co II, Ni II, and possibly Mn II. We find noindications for hydrogen, helium, or carbon in the spectra. The spectralfeatures reveal important clues about the physical characteristics ofSNe Ia. We use the features to derive upper limits for the amount ofunburned matter, to identify the transition regions from explosivecarbon to oxygen burning and from partial to complete silicon burning,and to estimate the level of mixing during and after the explosion.Elements synthesized in the outer layers during the explosion appear toremain in distinct layers. That provides strong evidence for thepresence of a detonation phase during the explosion as it occurs indelayed detonation or merger models. Mg II velocities are found toexceed 11,000-15,000 km s-1, depending on the individual SNeIa. That result suggests that burning during the explosion reaches theoutermost layers of the progenitor and limits the amount of unburnedmaterial to less than 10% of the mass of the progenitor. Small residualsof unburned material are predicted by delayed detonation models but areinconsistent with pure deflagration or merger models. Differences in thespectra of the individual SNe Ia demonstrate the variety of theseevents.
|Local velocity field from sosie galaxies. I. The Peebles' model|
Pratton et al. (1997) showed that the velocity field around clusterscould generate an apparent distortion that appears as tangentialstructures or radial filaments. In the present paper we determine theparameters of the Peebles' model (1976) describing infall of galaxiesonto clusters with the aim of testing quantitatively the amplitude ofthis distortion. The distances are determined from the concept of sosiegalaxies (Paturel 1984) using 21 calibrators for which the distanceswere recently calculated from two independent Cepheid calibrations. Weuse both B and I-band magnitudes. The Spaenhauer diagram method is usedto correct for the Malmquist bias. We give the equations for theconstruction of this diagram. We analyze the apparent Hubble constant indifferent regions around Virgo and obtain simultaneously the Local Groupinfall and the unperturbed Hubble constant. We found:[VLG-infall = 208 ± 9 km s-1] [\log H =1.82 ± 0.04 (H ≈ 66 ± 6 km s-1Mpc-1).] The front side and backside infalls can be seenaround Virgo and Fornax. In the direction of Virgo the comparison ismade with the Peebles' model. We obtain: [vinfall} =CVirgo/r0.9 ± 0.2] withCVirgo=2800 for Virgo and CFornax=1350 for Fornax,with the adopted units (km s-1 and Mpc). We obtain thefollowing mean distance moduli: [μVirgo=31.3 ± 0.2(r=18 Mpc )] [μFornax=31.7 ± 0.3 (r=22 Mpc). ] Allthese quantities form an accurate and coherent system. Full Table 2 isonly available in electronic form at the CDS via anonymous ftp tocdsarc.u-strasbg.fr (220.127.116.11) or viahttp://cdsweb.u-strasbg.fr/cgi-bin/qcat?J/A+A/393/57
|Supernova 2000do in NGC 6754|
IAUC 7509 available at Central Bureau for Astronomical Telegrams.
|Supernova 2000do in NGC 6754|
IAUC 7500 available at Central Bureau for Astronomical Telegrams.
|The NICMOS Snapshot Survey of Nearby Galaxies|
We present ``snapshot'' observations with the Near-Infrared Camera andMulti-Object Spectrometer (NICMOS) on board the Hubble Space Telescope(HST) of 94 nearby galaxies from the Revised Shapley Ames Catalog.Images with 0.2" resolution were obtained in two filters, a broadbandcontinuum filter (F160W, roughly equivalent to the H band) and anarrowband filter centered on the Paα line (F187N or F190N,depending on the galaxy redshift) with the 51^''x51^'' field of view ofthe NICMOS camera 3. A first-order continuum subtraction is performed,and the resulting line maps and integrated Paα line fluxes arepresented. A statistical analysis indicates that the average Paαsurface brightness in the central regions is highest in early-type(Sa-Sb) spirals.
|Supernova 1998dq in NGC 6754|
IAUC 7000 available at Central Bureau for Astronomical Telegrams.
|Supernova 1998dq in NGC 6754|
IAUC 6998 available at Central Bureau for Astronomical Telegrams.
|Supernova 1998X in NGC 6754|
IAUC 6847 available at Central Bureau for Astronomical Telegrams.
|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.
|A catalogue of spatially resolved kinematics of galaxies: Bibliography|
We present a catalogue of galaxies for which spatially resolved data ontheir internal kinematics have been published; there is no a priorirestriction regarding their morphological type. The catalogue lists thereferences to the articles where the data are published, as well as acoded description of these data: observed emission or absorption lines,velocity or velocity dispersion, radial profile or 2D field, positionangle. Tables 1, 2, and 3 are proposed in electronic form only, and areavailable from the CDS, via anonymous ftp to cdsarc.u-strasbg.fr (to18.104.22.168) or via http://cdsweb.u-strasbg.fr/Abstract.html
|Optical Rotation Curves and Linewidths for Tully-Fisher Applications|
Abstract image available at:http://adsabs.harvard.edu/cgi-bin/nph-bib_query?1997AJ....114.2402C&db_key=AST
|Parameters of 2447 Southern Spiral Galaxies for Use in the Tully-Fisher Relation|
I-band luminosities, rotational velocities, and redshifts of 1092 spiralgalaxies have been measured by CCD photometry and Hα spectroscopyusing the 1 m and 2.3 m telescopes at Siding Spring Observatory,respectively. The results are tabulated. Luminosity profiles andHα rotation curves are given for the galaxies. When these resultsare combined with similar data for 1355 spiral galaxies publishedpreviously (Mathewson, Ford, & Buchhorn, hereafter Paper I), itprovides a large, uniform, and unique data set with which to measure,via the Tully-Fisher relation, the peculiar velocities of galaxies inthe local universe to a distance of 11,000 km s^-1^ (Mathewson &Ford). Taking advantage of the opportunity for publishing this data inmachine-readable form, in the CD-ROM, we have also included similar datafor the 1355 galaxies in Paper I.
|Star formation in early-type galaxies of mixed pairs.|
We present optical imaging, spectroscopy and stellar populationsynthesis results for a sample of 4 mixed pairs of galaxies. The dataallow us to estimate the degree of interaction with reasonablecertainty. We conclude that one pair, AM1907-504, is likely to be anoptical alignment. The remaining systems show radial velocitydifferences and morphology consistent with the hypothesis that they arephysical binaries. Surface photometry allowed us to measure tidaldistortions in the spiral components and to identify internal structurein the early-type members. We also made a stellar population synthesisstudy of the early-type components and find evidence for a young stellarpopulation in the central regions of these galaxies. We considerpossible origins for the young component as due either to mass-transferfrom the spiral (cross-fuelling) or accretion events.
|Rotation Curves of 967 Spiral Galaxies|
We present the rotation curves of 967 southern spiral galaxies, obtainedby deprojecting and folding the raw Hα data originally publishedby Mathewson, Ford, & Buchhorn (1992). For 900 objects, we alsopresent, in figures and tables, the rotation curves smoothed on scalescorresponding to 5%-20% of the optical size; of these, 80 meet objectiveexcellence criteria and are suitable for individual detailed massmodeling, while 820, individually less compelling mainly because of themoderate statistics and/or limited extension, are suitable forstatistical studies. The remaining 67 curves suffer from severeasymmetries, small statistics, and large internal scatter that maylargely limit their use in galaxy structure studies. The deprojectedfolded curves, the smoothed curves, and various related quantities areavailable via anonymous ftp at galileo.sissa.it in the directory/users/ftp/pub/psrot.
|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.
|A volume-limited sample of IRAS galaxies to 4000 km/s, 3: CCD photometry from Palomar and Tololo observatories|
An all-sky, quasi-volume-limited sample of 251 spiral galaxies within4000 km/s has been extracted from the redshift survey of InfraredAstronomy Satellite (IRAS) galaxies by Strauss (1992). Distance modulifor these objects estimated via the Tully-Fisher (TF) method allow thepeculiar velocity field and the cosmological density parameter to beconstrained within this volume. The TF relation we exploit relatesdeprojected neutral hydrogen line width to near-infrared luminosity.Herein we present I and V band photometry for 159 members of this sampleobtained with charge coupled device (CCD) cameras at Palomar and Tololoobservatories. Image processing and photometric calibration proceduresare described. Twenty seven objects with multiple calibratedobservations suggest that isophotal I band magnitudes are reproduced toequal to or less than 0.05 mag precision at sigmaI = 23.5 magarcsec-2, and that systematic run-to-run offsets are limitedto equal to or less than 0.05 I mag.
|A volume-limited sample of IRAS galaxies to 4000 km/s, 2: Neutral hydrogen observations from the Parkes telescope|
We have extracted a volume-limited sample of spiral galaxies within 4000km/s from the Strauss et al. (1992) redshift survey of InfraredAstronomical Satellite (IRAS) galaxies. The purpose of the sample is touse distances obtained from the neutral hydrogen/near-infrared (I-band)Tully-Fisher relation to study deviations from uniform Hubble expansion.This will allow us to estimate the distribution of mass in the localuniverse and to place constraints on the value of the cosmologicaldensity parameter, omega 0. Here we report neutral hydrogen(H I) observations of 61 galaxies from this sample taken at the 64 mParkes telescope, 48 of which resulted in measured linewidth parameters.Empirical estimates of random and systematic errors in H I line widthsat low signal-to-noise ratio are described.
|A southern sky survey of the peculiar velocities of 1355 spiral galaxies|
The paper presents data from photometric and spectroscopic observationsof 1355 southern spiral galaxies and uses them to determine theirdistances and peculiar velocities via the Tully-Fisher (TF) relation.I-band CCD surface photometry was carried out using the 1-m and 3.9-mtelescopes at Siding Spring Observatory. H-alpha rotation curves for 965galaxies and 551 H I profiles are presented. The physical parameters,photometric and velocity data, distances, and peculiar velocities of thegalaxies are presented in tabular form. The mean distance, systemicvelocity, and average peculiar velocity of 24 clusters in the sample aregiven. TF diagrams are presented for each cluster.
|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.
|Dark matter in spiral galaxies|
The Tully-Fisher relation is used to probe dark matter (DM) in theoptical regions of spiral galaxies. By establishing it at severaldifferent isophotal radii in an appropriate sample of 58 galaxies withgood B-band photometry and rotation curves, it is shown that some of itsattributes (such as scatter, residuals, nonlinearity, and bias)dramatically decrease moving from the disk edge inward. This behaviorchallenges any mass model which assumes no DM or aluminosity-independent DM mass fraction interior to the optical radiusof spiral galaxies.
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