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Structure and kinematics of edge-on galaxy discs - IV. The kinematics of the stellar discs
The stellar disc kinematics in a sample of 15 intermediate- to late-typeedge-on spiral galaxies are studied using a dynamical modellingtechnique. The sample covers a substantial range in maximum rotationvelocity and deprojected face-on surface brightness and contains sevenspirals with either a boxy- or peanut-shaped bulge. Dynamical models ofthe stellar discs are constructed using the disc structure from I-bandsurface photometry and rotation curves observed in the gas. Thedifferences in the line-of-sight stellar kinematics between the modelsand absorption-line spectroscopy are minimized using a least-squaresapproach. The modelling constrains the disc surface density and stellarradial velocity dispersion at a fiducial radius through the freeparameter (σz/σR)-1, whereσz/σR is the ratio of vertical andradial velocity dispersion and M/L is the disc mass-to-light ratio. For13 spirals a transparent model provides a good match to the meanline-of-sight stellar velocity dispersion. Models that include arealistic radiative transfer prescription confirm that the effect ofdust on the observable stellar kinematics is small at the observed slitpositions. We discuss possible sources of systematic error and concludethat most of these are likely to be small. The exception is the neglectof the dark halo gravity, which has probably caused an overestimate ofthe surface density in the case of low surface brightness discs.
| The Baryonic Tully-Fisher Relation of Galaxies with Extended Rotation Curves and the Stellar Mass of Rotating Galaxies
I investigate the baryonic Tully-Fisher relation for a sample ofgalaxies with extended 21 cm rotation curves spanning the range 20 kms-1<~Vf<=300 km s-1. A variety ofscalings of the stellar mass-to-light ratio Υ* areconsidered. For each prescription for Υ*, I give fitsof the form Md=AVxf.Presumably, the prescription that comes closest to the correct valuewill minimize the scatter in the relation. The fit with minimum scatterhas A=50 Msolar km-4 s4 andx=4. This relation holds over five decades in mass. Galaxy color,stellar fraction, and Υ* are correlated with eachother and with Md, in the sense that more massivegalaxies tend to be more evolved. There is a systematic dependence ofthe degree of maximality of disks on surface brightness. High surfacebrightness galaxies typically have Υ*~3/4 of themaximum disk value, while low surface brightness galaxies typicallyattain ~1/4 of this amount.
| Deprojecting spiral galaxies using Fourier analysis. Application to the Ohio sample
We use two new methods developed recently (Barberàet al.\cite{bar03}, A&A, 415, 849), as well as information obtained fromthe literature, to calculate the orientation parameters of the spiralgalaxies in the Ohio State University Bright Galaxy Survey. We comparethe results of these methods with data from the literature, and find ingeneral good agreement. We provide a homogeneous set of mean orientationparameters which can be used to approximately deproject the disks of thegalaxies and facilitate a number of statistical studies of galaxyproperties.Table 1 is only available in electronic form at the CDS via anonymousftp to cdsarc.u-strasbg.fr (130.79.128.5) or viahttp://cdsweb.u-strasbg.fr/cgi-bin/qcat?J/A+A/421/595
| The WSRT wide-field H I survey. I. The background galaxy sample
We have used the Westerbork array to carry out an unbiased wide-fieldsurvey for H I emission features, achieving an RMS sensitivity of about18 mJy/Beam at a velocity resolution of 17 km s-1 over 1800deg2 and between -1000 < VHel <+6500 kms-1. The primary data consists of auto-correlation spectrawith an effective angular resolution of 49' FWHM, althoughcross-correlation data were also acquired. The survey region is centeredapproximately on the position of Messier 31 and is Nyquist-sampled over60x 30o in RA x Dec. More than 100 distinct features aredetected at high significance in each of the two velocity regimes(negative and positive LGSR velocities). In this paper we present theresults for our H I detections of external galaxies at positive LGSRvelocity. We detect 155 external galaxies in excess of 8sigma inintegrated H I flux density. Plausible optical associations are foundwithin a 30' search radius for all but one of our H I detections in DSSimages, although several are not previously cataloged or do not havepublished red-shift determinations. Our detection without a DSSassociation is at low galactic latitude. Twenty-three of our objects aredetected in H I for the first time. We classify almost half of ourdetections as ``confused'', since one or more companions is catalogedwithin a radius of 30' and a velocity interval of 400 km s-1.We identify a handful of instances of significant positional offsetsexceeding 10 kpc of unconfused optical galaxies with the associated H Icentroid, possibly indicative of severe tidal distortions or uncatalogedgas-rich companions. A possible trend is found for an excess of detectedH I flux in unconfused galaxies within our large survey beam relative tothat detected previously in smaller telescope beams, both as function ofincreasing distance and increasing gas mass. This may be an indicationfor a diffuse gaseous component on 100 kpc scales in the environment ofmassive galaxies or a population of uncataloged low mass companions. Weuse our galaxy sample to estimate the H I mass function from our surveyvolume. Good agreement is found with the HIPASS BGC results, but onlyafter explicit correction for galaxy density variations with distance.Table 1 is only available in electronic form at the CDS via anonymousftp to cdsarc.u-strasbg.fr (130.79.128.5) or viahttp://cdsweb.u-strasbg.fr/cgi-bin/qcat?J/A+A/406/829 and Fig. 3 is onlyavailable in electronic form at http://www.edpsciences.org
| Modified Newtonian Dynamics as an Alternative to Dark Matter
Modified Newtonian dynamics (MOND) is an empirically motivatedmodification of Newtonian gravity or inertia suggested by Milgrom as analternative to cosmic dark matter. The basic idea is that ataccelerations below ao ~ 10-8 cm/s2 ~cHo/6 the effective gravitational attraction approaches√(gnao), where gn is the usualNewtonian acceleration. This simple algorithm yields flat rotationcurves for spiral galaxies and a mass-rotation velocity relation of theform M ∝ V4 that forms the basis for the observedluminosity-rotation velocity relation-the Tully-Fisher law. We reviewthe phenomenological success of MOND on scales ranging from dwarfspheroidal galaxies to superclusters and demonstrate that the evidencefor dark matter can be equally well interpreted as evidence for MOND. Wediscuss the possible physical basis for an acceleration-basedmodification of Newtonian dynamics as well as the extention of MOND tocosmology and structure formation.
| Determination of Distances to Galaxies of the NGC 1023 Group. The Hubble Constant
On the basis of photographs from the 6 m Large Azimuthal Telescope andthe Hubble Space Telescope, VRI photometry of stars in 11 galaxies inthe NGC 1023 group has been carried out. The distances to these galaxieswere determined by the method of brightest stars. The distances to NGC925 and NGC 1023 were determined from the position of the top of the redgiant branch (the TRGB method). From the calculated average androot-mean-square distances to the NGC 1023 group (10.3 ± 2.2 Mpcand 9.7 ± 0.5 Mpc) the Hubble constant in this direction wasdetermined: H 0R = 75 ± 8 km·sec-1·Mpc-1 and H 0M =81 ± 5 km ·sec-1·Mpc-1.
| The UZC-SSRS2 Group Catalog
We apply a friends-of-friends algorithm to the combined Updated ZwickyCatalog and Southern Sky Redshift Survey to construct a catalog of 1168groups of galaxies; 411 of these groups have five or more members withinthe redshift survey. The group catalog covers 4.69 sr, and all groupsexceed the number density contrast threshold, δρ/ρ=80. Wedemonstrate that the groups catalog is homogeneous across the twounderlying redshift surveys; the catalog of groups and their membersthus provides a basis for other statistical studies of the large-scaledistribution of groups and their physical properties. The medianphysical properties of the groups are similar to those for groupsderived from independent surveys, including the ESO Key Programme andthe Las Campanas Redshift Survey. We include tables of groups and theirmembers.
| The Mount Wilson Halo Mapping Project 1975-1985. II. Photometric Properties of the Mount Wilson Catalogue of Photographic Magnitudes in Selected Areas 1-139
This paper is partly a review of the history of the making of the MountWilson Catalogue of Photographic Magnitudes in Selected Areas 1-139(hereafter the MWC), begun in 1909 and completed in 1930, and it ispartly the presentation of new photometric results concerning it.Photoelectric photometry of 435 stars in the 11 Selected Areas of SA 28,29, 45, 55, 57, 71, 82, 94, 106, 107, and 118 of the MWC is given. Thedata are used to derive magnitude corrections to the MWC for theseareas. Ten of the areas are in the Galactic meridional plane (Galacticlongitudes of 0° and 180°). These are the same areas used byBecker in his Basel program of star counts for the study of Galacticstructure. The first purpose of the paper is to extend the Basel starcounts to fainter magnitudes. For this, 200 inch photographic plateswere measured to the plate limits near B=22, calibrated with thephotoelectric photometry listed here. A second purpose is to derivecertain properties of the catalog. The interests are (1) to determinethe internal (random) measuring errors of the MWC as a function ofmagnitude after correcting for the systematic scale error in each area,(2) to test for a color equation between the correctedmpg(MWC) values and the Bpe system that must bepresent because of the difference in reflectivity between silvered andaluminized mirrors, and (3) to test for possible distance-to-centercorrections of the scale-corrected MWC magnitudes. Photographicphotometry is used to complete the count surveys in each of the programareas to the limit of the 200 inch plates. Color-magnitude diagrams areshown for each area, generally complete to V=20, B-V=2.0. The work ispreparatory to an analysis for Galactic structure when the largerdatabase is available in a program by Majewski using Kitt Peak 4 mplates, epoch circa 1975, that will be to provide both a deeper countsurvey in B and V and proper motions for the larger sample.
| Supernovae in isolated galaxies, in pairs and in groups of galaxies
In order to investigate the influence of environment on supernova (SN)production, we have performed a statistical investigation of the SNediscovered in isolated galaxies, in pairs and in groups of galaxies. 22SNe in 18 isolated galaxies, 48 SNe in 40 galaxy members of 37 pairs and211 SNe in 170 galaxy members of 116 groups have been selected andstudied. We found that the radial distributions of core-collapse SNe ingalaxies located in different environments are similar, and consistentwith those reported by Bartunov, Makarova & Tsvetkov. SNe discoveredin pairs do not favour a particular direction with respect to thecompanion galaxy. Also, the azimuthal distributions inside the hostmembers of galaxy groups are consistent with being isotropics. The factthat SNe are more frequent in the brighter components of the pairs andgroups is expected from the dependence of the SN rates on the galaxyluminosity. There is an indication that the SN rate is higher in galaxypairs compared with that in groups. This can be related to the enhancedstar formation rate in strongly interacting systems. It is concludedthat, with the possible exception of strongly interacting systems, theparent galaxy environment has no direct influence on SN production.
| On the apparent coupling of neutral hydrogen and dark matter in spiral galaxies
We have studied a mass model for spiral galaxies in which the darkmatter surface density is a scaled version of the observed Hi surfacedensity. Applying this mass model to a sample of 24 spiral galaxies withreliable rotation curves, one obtains good fits for most galaxies. Thescaling factors cluster around 7, after correction for the presence ofprimordial helium. For several cases, however, different, often larger,values are found. For galaxies that cannot be fitted well, thediscrepancy occurs at large radii and results from a fairly rapiddecline of the Hi surface density in the outermost regions. Because ofsuch imperfections and in view of possible selection effects, it is notpossible to conclude here that there is a real coupling between Hi anddark matter in spiral galaxies.
| Cepheid Calibration of the Peak Brightness of Type IA Supernovae. X. SN 1991T in NGC 4527
Repeated imaging observations have been made of NGC 4527 with the HubbleSpace Telescope between 1999 April and June, over an interval of 69days. Images were obtained on 12 epochs in the F555W band and on fiveepochs in the F814W band. The galaxy hosted the Type Ia supernova SN1991T, which showed relatively unusual behavior by having both anabnormal spectrum near light maximum, and a slower declining light curvethan the prototypical Branch-normal SNe Ia. A total of 86 variables thatare putative Cepheids have been found, with periods ranging from 7.4days to over 70 days. From photometry with the DoPHOT program, thedereddened distance modulus is determined to be(m-M)0=30.67+/-0.12 (internal uncertainty) using a subset ofthe Cepheid data whose reddening and error parameters are secure. Aparallel analysis of the Cepheids using photometry with ROMAFOT yields(m-M)0=30.82+/-0.11. The final adopted modulus is(m-M)0=30.74+/-0.12+/-0.12 (d=14.1+/-0.8+/-0.8 Mpc). Thephotometric data for SN 1991T are used in combination with the Cepheiddistance to NGC 4527 to obtain the absolute magnitude for this supernovaof M0V(max)=-19.85+/-0.29. The relatively largeuncertainty is a result of the range in estimates of the reddening tothe supernova. Thus, SN 1991T is seen to be only moderately brighter (by~0.3 mag) than the mean for spectroscopically normal supernovae,although magnitude differences of up to 0.6 mag cannot be ruled out.
| Lick Observatory Photographic Supernova Spectra
Seventy-eight photographic spectra of 18 bright supernovae that wereobtained by various observers at the Lick Observatory between 1937 and1971 are presented and briefly discussed. Microphotometer transmissiontracings of the photographic plates have been digitized and plotted on acommon scale with a linear wavelength axis. The spectra were prismatic,with a nonlinear dispersion, in their original form. These spectra areuseful for classification purposes and for comparative studies of theblueshifts of absorption features.
| Is a Simple Collisionless Relic Dark Matter Particle Ruled Out?
The central densities of dark matter (DM) halos are much lower thanpredicted in cold DM models of structure formation. Confirmation thatthey have cores with a finite central density would allow us to rule outmany popular types of collisionless particles as candidates for DM. Anymodel that leads to cusped halos (such as cold DM) is already facingserious difficulties on small scales, and hot DM models have beenexcluded. Here I show that fermionic warm DM is inconsistent with thewide range of phase-space densities in the DM halos of well-observednearby galaxies.
| The Various Kinematics of Dwarf Irregular Galaxies in Nearby Groups and Their Dark Matter Distributions
Eight dwarf irregular galaxies, in the two nearby groups of galaxiesSculptor and Centaurus A (at 2.5 Mpc and 3.5 Mpc), have been imaged inneutral hydrogen (H I) with the Australia Telescope and the Very LargeArray. These galaxies have absolute magnitudes ranging fromMB=-15.7 to -11.3. Yet they are mostly rotationallysupported, with maximum velocities going from 19 to 67 kms-1. Multicomponent mass models have been fitted to therotation curves to investigate the properties of their dark matter halosand the scaling laws of dark matter halo parameters. Dwarf galaxieshave, on average, a higher dark to luminous mass ratio, as well ashigher dark halo central densities than spiral galaxies. They have alarger dispersion of their dark matter properties both in terms of theirtotal dark matter amount and of their dark halo parameters, compared tospiral galaxies. It is therefore very difficult to predict a dwarfgalaxy rotation curve shape based only on its optical properties. Dwarfsare not well fitted by cold dark matter (CDM) halos of the type proposedby Navarro, Frenk, & White, even for ΛCDM models withΩ0 as low as 0.3. For two of our dwarfs we also haveHα rotation curves confirming the H I velocities, so thediscrepancy with the CDM models cannot be attributed to beam-smearingeffects.
| The Nuclear Activity of Galaxies in the Hickson Compact Groups
In order to investigate the nuclear activity of galaxies residing incompact groups of galaxies, we present results of our opticalspectroscopic program made at Okayama Astrophysical Observatory. We haveperformed optical spectroscopy of 69 galaxies belonging to 31 Hicksoncompact groups (HCGs) of galaxies. Among them, three galaxies havediscordant redshifts and, moreover, spectral quality is too poor toclassify another three galaxies. Therefore, we describe our results forthe remaining 63 galaxies. Our main results are summarized as follows:(1) We have found in our sample 28 active galactic nuclei (AGNs), 16 HII nuclei, and 19 normal galaxies showing no emission line. We used thisHCG sample for statistical analyses. (2) Comparing the frequencydistributions of activity types between the HCGs and the field galaxieswhose data are taken from Ho, Filippenko, & Sargent (382 fieldgalaxies), we find that the frequency of H II nuclei in the HCGs issignificantly less than that in the field. However, this difference maybe due to selection bias to the effect that our HCG sample contains moreearly-type galaxies than the field, because it is known that H II nucleiare rarer in early-type galaxies than in later ones. (3) Applying acorrection to this morphological bias to the HCG sample, we find thatthere is no statistically significant difference in the frequency ofoccurrence of emission-line galaxies between the HCGs and the field.This implies that the dense galaxy environment in the HCGs does notaffect the triggering of either the AGN activity and the nuclearstarburst. We discuss some implications on the nuclear activity in theHCG galaxies.
| Box- and peanut-shaped bulges. I. Statistics
We present a classification for bulges of a complete sample of ~ 1350edge-on disk galaxies derived from the RC3 (Third Reference Catalogue ofBright Galaxies, de Vaucouleurs et al. \cite{rc3}). A visualclassification of the bulges using the Digitized Sky Survey (DSS) inthree types of b/p bulges or as an elliptical type is presented andsupported by CCD images. NIR observations reveal that dust extinctiondoes almost not influence the shape of bulges. There is no substantialdifference between the shape of bulges in the optical and in the NIR.Our analysis reveals that 45% of all bulges are box- and peanut-shaped(b/p). The frequency of b/p bulges for all morphological types from S0to Sd is > 40%. In particular, this is for the first time that such alarge frequency of b/p bulges is reported for galaxies as late as Sd.The fraction of the observed b/p bulges is large enough to explain theb/p bulges by bars. Partly based on observations collected at ESO/LaSilla (Chile), DSAZ/Calar Alto (Spain), and Lowell Observatory/Flagstaff(AZ/U.S.A.). Tables 6 and 7 are only available in electronic form at CDSvia anonymous ftp to cdsarc.u-strasbg.fr (130.79.128.5) or viahttp://cdsweb.u-strasbg.fr/Abstract.html
| 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.
| Central Rotation Curves of Spiral Galaxies
We present high-resolution central-to-outer rotation curves for Sb, SBb,Sc, and SBc galaxies. We discuss their general characteristics,particularly their central behavior, as well as dependencies onmorphological types, activity, and peculiarity. The rotation curvesgenerally show a steep nuclear rise and high-velocity central rotation,followed by a broad maximum in the disk and then a flat rotation due tothe massive halo. Since the central high velocity and steep rise arecommon to all massive galaxies, they cannot be due to noncircularmotions. Disk rotation curves of barred galaxies show larger dispersionthan those of normal galaxies, probably because of noncircular motions.Interacting galaxies often show perturbed outer rotation curves, whiletheir central rotation shows no particular peculiarity. In addition,central activities, such as starbursts and active galactic nuclei,appear to show no particular correlation with the property of rotationcurves. This would suggest that the central activities are triggered bya more local effect than the global dynamical property.
| Maximal Disks and the Tully-Fisher Relation
We show that for luminous, nonbarred, high surface brightness (HSB)spirals the Tully-Fisher relation (TFR) residuals can be used toestimate the relative mass contributions of the stellar disk and thedark halo at the peak of the disk rotation, near 2.2 exponential scalelengths. For ``maximal disks,'' a large fraction (0.85+/-0.1) of thetotal rotational support, V_2.2, at such radii should arise from theirstellar mass. Therefore, the disk size or surface-brightness should be asignificant additional parameter in the TFR. At a given absoluteluminosity, M_r, more compact disks (as measured by the disk scalelength R_exp) should have higher rotation speeds, V_2.2. Using awell-defined sample of late-type spirals, deviations, DeltalogV_2.2, andDeltalogR_exp, from the mean relations, V_2.2(M_r) and R_exp(M_r), arenot significantly correlated. The case of∂logV_2.2/∂logR_exp=-0.5 expected for a maximal disk is ruledout for the majority of these HSB galaxies. We model adiabatic infall ofvarying amounts of luminous matter into dark matter halos to explore therange of possible values for ∂logV_2.2/∂logR_exp. From this,we find that the TFR residuals require a mean value ofV_disk~0.6V_total, fairly insensitive to the details of the initial darkmatter halo and to the presence of a bulge. This translates toM_halo~0.6M_total within 2.2R_exp or roughly twice more dark matter inthe inner parts of late-type spirals than previously accounted for bymaximum disk fits. We show that any stellar population differencesbetween disks of different scale lengths lead to lower values ofV_disk/V_total. Our result is independent of the shape of the luminosityprofile and relies only on the assumption of adiabatic contraction andthat the dark matter halo rotation rises in the central parts of thegalaxy. Submaximal disks establish a natural continuity between HSB andlow surface brightness galaxies, which appear to be completely darkmatter dominated even in their inner regions.
| The Environments of Supernovae in Post-Refurbishment Hubble Space Telescope Images
The locations of supernovae (SNe) in the local stellar and gaseousenvironment in galaxies contain important clues to their progenitorstars. Access to this information, however, has been hampered by thelimited resolution achieved by ground-based observations. High spatialresolution Hubble Space Telescope (HST) images of galaxy fields in whichsupernovae had been observed can improve the situation considerably. Wehave examined the immediate environments of a few dozen supernovae usingarchival post-refurbishment HST images. Although our analysis is limitedbecause of signal-to-noise ratio and filter bandpass considerations, theimages allow us for the first time to resolve individual stars in, andto derive detailed color-magnitude diagrams for, several environments.We are able to place more rigorous constraints on the masses of thesesupernovae. A search was made for late-time emission from supernovae inthe archival images and for the progenitor stars in presupernova imagesof the host galaxies. We have detected SN 1986J in NGC 891 and,possibly, SN 1981K in NGC 4258. We have also identified the progenitorof the Type IIn SN 1997bs in NGC 3627. By removing younger resolvedstars in the environments of SNe Ia, we can measure the colors of theunresolved stellar background and attribute these colors generally to anolder, redder population. HST images ``accidentally'' caught the Type IaSN 1994D in NGC 4526 shortly after its outburst; we measure itsbrightness. Finally, we add to the statistical inferences that can bemade from studying the association of SNe with recent star-formingregions.
| A search for candidate light echoes: Photometry of supernova environments
Supernova (SN) light echoes could be a powerful tool for determiningdistances to galaxies geometrically, \cite[Sparks (1994)]{S94}. In thispaper we present CCD photometry of the environments of 64 historicalsupernovae, the first results of a program designed to search for lightechoes from these SNe. We commonly find patches of optical emission at,or close to, the sites of the supernovae. The color distribution ofthese patches is broad, and generally consistent with stellar populationcolors, possibly with some reddening. However there are in additionpatches with both unusually red and unusually blue colors. We expectlight echoes to be blue, and while none of the objects are quite as bluein V-R as the known light echo of SN 1991T, there are features that areunusually blue and we identify these as candidate light echoes forfollow-on observations. Tables 2a and 2b are also available at the CDSvia anonymous ftp to cdsarc.u-strasbg.fr (130.79.128.5) or viahttp://cdsweb.u-strasbg.fr/Abstract.html and Figs. 1 through 36 are onlyavailable in the online version of the journal athttp://www.edpsciences.com
| Nuclear-to-Disk Rotation Curves of Galaxies in the Hα and [N {II}] Emission Lines
We have obtained optical CCD spectroscopy along the major axes of 22nearby spiral galaxies of Sb and Sc types in order to analyze theirrotation curves. By subtracting the stellar continuum emission, we haveobtained position--velocity (PV) diagrams of the Hα and [N II]lines. We point out that the Hα line is often superposed by a broadstellar absorption feature (Balmer wing) in the nuclear regions, and,therefore, the [N II] line is a better tracer of kinematics in thecentral few hundred parsec regions. By applying the envelope-tracingtechnique to the Hα and [N II] PV diagrams, we have derivednucleus-to-disk rotation curves of the observed galaxies. The rotationcurves rise steeply within the central few hundred parsecs, indicating arapidly rotating nuclear disk and mass concentration near the nucleus.
| Catalogue of HI maps of galaxies. I.
A catalogue is presented of galaxies having large-scale observations inthe HI line. This catalogue collects from the literature the informationthat characterizes the observations in the 21-cm line and the way thatthese data were presented by means of maps, graphics and tables, forshowing the distribution and kinematics of the gas. It containsfurthermore a measure of the HI extension that is detected at the levelof the maximum sensitivity reached in the observations. This catalogueis intended as a guide for references on the HI maps published in theliterature from 1953 to 1995 and is the basis for the analysis of thedata presented in Paper II. The catalogue is only available inelectronic form at the CDS via anonymous ftp 130.79.128.5 orhttp://cdsweb.u-strasbg.fr/Abstract.html
| 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 (to130.79.128.5) or via http://cdsweb.u-strasbg.fr/Abstract.html
| HIPPARCOS calibration of the peak brightness of four SNe IA and the value of H_0
HIPPARCOS geometrical parallaxes allowed us to calibrate the CepheidPeriod-Luminosity relation and to compute the true distance moduli of 17galaxies. Among these 17 galaxies, we selected those which generatedtype Ia Supernovae (SNe Ia). We found NGC 5253, parent galaxy of 1895Band 1972E, IC 4182 and NGC 4536 parents of 1937C and 1981B,respectively. We used the available B-band photometry to determine thepeak brightness of these four SNe Ia. We obtained = -19.65 +/- 0.09. Then, we built a sample of 57SNe Ia in order to plot the Hubble diagram and determine its zero-point.Our result (ZPB = -3.16 +/- 0.10) is in agreement with otherdeterminations and allows us to derive the following Hubble constant:H0 = 50 +/- 3 (internal) km.s(-1}.Mpc({-1)) .
| A test of Tully-Fisher distance estimates using Cepheids and SNIa
We make a direct test of Tully-Fisher distance estimates to 11 spiralgalaxies with Hubble Space Telescope (HST) Cepheid distances, and to 12spiral galaxies with Type Ia supernova (SNIa) distances. The HST Cepheiddistances come from the work of Freedman, Sandage et al. and Tanvir etal. The SNIa distances come from Pierce, calibrated using the Cepheidresults of Sandage et al. The Tully-Fisher distances mostly come fromthe work of Pierce. The results show that the Tully-Fisher distancemoduli are too short with respect to the Cepheid distances by0.41+/-0.14 mag, and too short with respect to the SNIa distances by0.46+/-0.19 mag. Combining the HST Cepheid and SNIa data suggests that,overall, previous Tully-Fisher distances were too short by 0.43+/-0.11mag, a result which is significant at the 3.8sigma level. TheTully-Fisher distance errors appear to increase as galaxy linewidthdecreases, which may signify the presence of Malmquist bias. These datatherefore indicate that previous Tully-Fisher distances at v~1000 kms^-1 should be revised upwards by ~22+/-6 per cent implying, forexample, a Virgo distance of 19.0+/-1.8 Mpc. The value of H_0 fromTully-Fisher estimates is correspondingly revised downwards fromH_0=84+/-10 to H_0=69+/-8 km s^-1 Mpc^-1.
| The dark and visible matter content of low surface brightness disc galaxies
We present mass models of a sample of 19 low surface brightness (LSB)galaxies and compare the properties of their constituent mass componentswith those of a sample of high surface brightness (HSB) galaxies. Wefind that LSB galaxies are dark matter dominated. Their halo parametersare only slightly affected by assumptions on stellar mass-to-lightratios. Comparing LSB and HSB galaxies we find that mass models derivedusing the maximum disc hypothesis result in the discs of LSB galaxieshaving systematically higher stellar mass-to-light ratios than HSBgalaxies of similar rotation velocity. This is inconsistent with allother available evidence on the evolution of LSB galaxies. We arguetherefore that the maximum disc hypothesis does not provide arepresentative description of the LSB galaxies and their evolution. Massmodels with stellar mass-to-light ratios determined by the colours andstellar velocity dispersions of galactic discs imply that LSB galaxieshave dark matter haloes that are more extended and less dense than thoseof HSB galaxies. Surface brightness is thus related to the haloproperties. LSB galaxies are slowly evolving, low-density and darkmatter dominated galaxies.
| A Search for ``Dwarf'' Seyfert Nuclei. III. Spectroscopic Parameters and Properties of the Host Galaxies
We have completed an optical spectroscopic survey of the nuclear regions(r <~ 200 pc) of a large sample of nearby galaxies. Although the mainobjectives of the survey are to search for low-luminosity activegalactic nuclei and to quantify their luminosity function, the databasecan be used for a variety of other purposes. This paper presentsmeasurements of the spectroscopic parameters for the 418 emission-linenuclei, along with a compilation of the global properties of all 486galaxies in the survey. Stellar absorption generally poses a seriousobstacle to obtaining accurate measurement of emission lines in nearbygalactic nuclei. We describe a procedure for removing the starlight fromthe observed spectra in an efficient and objective manner. The mainparameters of the emission lines (intensity ratios, fluxes, profilewidths, and equivalent widths) are measured and tabulated, as areseveral stellar absorption-line and continuum indices useful forstudying the stellar population. Using standard nebular diagnostics, wedetermine the probable ionization mechanisms of the emission-lineobjects. The resulting spectral classifications provide extensiveinformation on the demographics of emission-line nuclei in the nearbyregions of the universe. This new catalog contains over 200 objectsshowing spectroscopic evidence for recent star formation and an equallylarge number of active galactic nuclei, including 46 that show broad Halpha emission. These samples will serve as the basis of future studiesof nuclear activity in nearby galaxies.
| Nuclear Rotation Curves of Galaxies in the Co-Line Emission
Abstract image available at:http://adsabs.harvard.edu/cgi-bin/nph-bib_query?1997AJ....114.2428S&db_key=AST
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Gözlemler ve gökölçümü verileri
Kataloglar ve belirtme:
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