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Scalar potential model of redshift and discrete redshift
On the galactic scale the universe is inhomogeneous and redshift z isoccasionally less than zero. A scalar potential model (SPM) that linksthe galaxy scale z to the cosmological scale z of the Hubble Law ispostulated. Several differences among galaxy types suggest that spiralgalaxies are Sources and that early type, lenticular, and irregulargalaxies are Sinks of a scalar potential field. The morphology-radiusand the intragalactic medium cluster observations support the movementof matter from Source galaxies to Sink galaxies. A cell structure ofgalaxy groups and clusters is proposed to resolve a paradox concerningthe scalar potential like the Olber’s paradox concerning light.For the sample galaxies, the ratio of the luminosity of Source galaxiesto the luminosity of Sink galaxies approaches 2.7 ± 0.1. Anequation is derived from sample data, which is anisotropic andinhomogeneous, relating z of and the distance D to galaxies. Thecalculated z has a correlation coefficient of 0.88 with the measured zfor a sample of 32 spiral galaxies with D calculated using Cepheidvariable stars. The equation is consistent with z < 0 observations ofclose galaxies. At low cosmological distances, the equation reduces to z≈ exp(KD)‑1 ≈ KD, where K is a constant, positive value. Theequation predicts z from galaxies over 18 Gpc distant approaches aconstant value on the order of 500. The SPM of z provides a physicalbasis for the z of particle photons. Further, the SPM qualitativelysuggests the discrete variations in z, which was reported by Tifft[Tifft, W.G., 1997. Astrophy. J. 485, 465] and confirmed by others, areconsistent with the SPM.
| Star Formation in H I-selected Galaxies. II. H II Region Properties
A sample of 69 galaxies with radial velocities less than 2500 kms-1 was selected from the H I Parkes All Sky Survey (HIPASS)to deduce details about star formation in nearby disk galaxies selectedwith no bias to optical surface brightness selection effects. Broadband(B and R) and narrowband (Hα) images were obtained for all ofthese objects. More than half of the sample galaxies are late-type,dwarf disks (mostly Sc and Sm galaxies). We have measured the propertiesof the H II regions on Hα continuum-subtracted images, using theHIIphot package developed by Thilker et al. All but one of the galaxiescontained at least one detectable H II region. Examination of theproperties of the H II regions in each galaxy revealed that thebrightest regions in higher surface brightness galaxies tend to be moreluminous than those in lower surface brightness galaxies. A higherfraction (referred to as the diffuse fraction) of the Hα emissionfrom lower surface brightness galaxies comes from diffuse ionized gas. HII region luminosity functions (LFs) co-added according to surfacebrightness show that the shapes of the LFs for the lowest surfacebrightness galaxies are different from those for typical spiralgalaxies. This discrepancy could be caused by the lowest surfacebrightness galaxies having somewhat episodic star formation or by themforming a relatively larger fraction of their stars outside of dense,massive molecular clouds. In general, the results imply that theconditions under which star formation occurs in lower surface brightnessgalaxies are different than in more typical, higher surface brightnessspiral galaxies.
| Star Formation in H I-Selected Galaxies. I. Sample Characteristics
A sample of 69 galaxies with radial velocities of less than 2500 kms-1 was selected from the H I Parkes All-Sky Survey (HIPASS)and imaged in broadband B and R and narrowband Hα, to deducedetails about star formation in nearby disk galaxies while avoidingsurface brightness selection effects. The sample is dominated bylate-type, dwarf disks (mostly Sc and Sm galaxies) with exponential diskscale lengths of ~1-5 kpc. The HIPASS galaxies, on average, have lowerstar formation rates (SFRs), are bluer, and have lower surfacebrightness than an optically selected sample. H II regions were detectedin all but one of the galaxies. Many galaxies had as few as two to fiveH II regions. The galaxies' Hα equivalent widths, colors, and SFRsper unit of H I mass are best explained by young mean ages (~3-5 Gyr,according to Schmidt-law models) with star formation histories in whichthe SFRs were higher in the past. Comparison of the surface brightnesscoverage of the HIPASS galaxies with that of an optically selectedsample shows that such a sample may miss ~10% of the local galaxy numberdensity and could possibly miss as much as 3%-4% of the SFR density. Theamount lower surface brightness galaxies contribute to the totalluminosity density may be insignificant, but this conclusion is somewhatdependent on how the fluxes of these objects are determined.
| A new catalogue of ISM content of normal galaxies
We have compiled a catalogue of the gas content for a sample of 1916galaxies, considered to be a fair representation of ``normality''. Thedefinition of a ``normal'' galaxy adopted in this work implies that wehave purposely excluded from the catalogue galaxies having distortedmorphology (such as interaction bridges, tails or lopsidedness) and/orany signature of peculiar kinematics (such as polar rings,counterrotating disks or other decoupled components). In contrast, wehave included systems hosting active galactic nuclei (AGN) in thecatalogue. This catalogue revises previous compendia on the ISM contentof galaxies published by \citet{bregman} and \citet{casoli}, andcompiles data available in the literature from several small samples ofgalaxies. Masses for warm dust, atomic and molecular gas, as well asX-ray luminosities have been converted to a uniform distance scale takenfrom the Catalogue of Principal Galaxies (PGC). We have used twodifferent normalization factors to explore the variation of the gascontent along the Hubble sequence: the blue luminosity (LB)and the square of linear diameter (D225). Ourcatalogue significantly improves the statistics of previous referencecatalogues and can be used in future studies to define a template ISMcontent for ``normal'' galaxies along the Hubble sequence. The cataloguecan be accessed on-line and is also available at the Centre desDonnées Stellaires (CDS).The catalogue is available in electronic form athttp://dipastro.pd.astro.it/galletta/ismcat and at the CDS via anonymousftp to\ cdsarc.u-strasbg.fr (130.79.128.5) or via\http://cdsweb.u-strasbg.fr/cgi-bin/qcat?J/A+A/405/5
| A Catalog of H I-Selected Galaxies from the South Celestial Cap Region of Sky
The first deep catalog of the H I Parkes All Sky Survey (HIPASS) ispresented, covering the south celestial cap (SCC) region. The SCC areais ~2400 deg2 and covers δ<-62°. The average rmsnoise for the survey is 13 mJy beam-1. Five hundredthirty-six galaxies have been cataloged according to their neutralhydrogen content, including 114 galaxies that have no previous catalogedoptical counterpart. This is the largest sample of galaxies from a blindH I survey to date. Most galaxies in optically unobscured regions of skyhave a visible optical counterpart; however, there is a small populationof low-velocity H I clouds without visible optical counterparts whoseorigins and significance are unclear. The rms accuracy of the HIPASSpositions is found to be 1.9′. The H I mass range of galaxiesdetected is from ~106 to ~1011 Msolar.There are a large number of late-type spiral galaxies in the SCC sample(66%), compared with 30% for optically selected galaxies from the sameregion in the NASA Extragalactic Database. The average ratio of H I massto B luminosity of the sample increases according to optical type, from1.8 Msolar/Lsolar for early types to 3.2Msolar/Lsolar for late-type galaxies. The HI-detected galaxies tend to follow the large-scale structure traced bygalaxies found in optical surveys. From the number of galaxies detectedin this region of sky, we predict the full HIPASS catalog will contain~5000 galaxies, to a peak flux density limit of ~39 mJy (3 σ),although this may be a conservative estimate as two large voids arepresent in the region. The H I mass function for this catalog ispresented in a subsequent paper.
| Background galaxies as reddening probes throughout the Magellanic Clouds
We study the spectral properties in the range 3600 Å-6800 Åof the nuclear region of galaxies behind the Magellanic Clouds. Theradial velocities clarified the nature of the objects as backgroundgalaxies or extended objects belonging to the Clouds. For most galaxiesbehind the main bodies of the LMC and SMC, radial velocities weremeasured for the first time. In the present sample typical LMCbackground galaxies are nearby (4000 < V(km s-1) <6000), while SMC's are considerably more distant (10 000 < V(kms-1) < 20 000). We determine the reddening in each line ofsight by matching a reddening-free galaxy template with comparablestellar population. For the LMC main body we derive a combined Milky Wayand internal reddening value E(B-V)MW+i = 0.12 +/- 0.10,while for the SMC E(B-V)MW+i = 0.05 +/- 0.05. By subtractingMilky Way reddening values for galaxies projected onto the surroundingsof each Cloud, we estimate average internal reddening values DeltaE(B-V)i = 0.06 and 0.04, respectively for the main bodies ofthe LMC and SMC. The Clouds are optically thin, at least in thedirections of the studied background galaxies which are often difficultto be identified as such on ESO/SERC sky survey images. Nevertheless,more reddened zones may occur where it is difficult to identifygalaxies.
| H I in Four Star-forming Low-Luminosity E/S0 and S0 Galaxies
We present H I data cubes of four low-luminosity early-type (E/S0 andS0) galaxies that are currently forming stars. These galaxies haveabsolute magnitudes in the range MB=-17.9 to -19.9(H0=50 km s-1 Mpc-1). Their H I massesrange between a few times 108 and a few times 109Msolar, and the corresponding values forMHI/LB are between 0.07 and 0.42, so these systemsare H I-rich for their morphological type. In all four galaxies, the H Iis strongly centrally concentrated with high central H I surfacedensities, in contrast to what is typically observed in more luminousearly-type galaxies. Star formation is occurring only in the centralregions. In two galaxies (NGC 802 and ESO 118-G34), the kinematics ofthe H I suggests that the gas is in a strongly warped disk, which wetake as evidence for recent accretion of H I. In the other two galaxies(NGC 2328 and ESO 027-G21), the H I must have been part of the systemsfor a considerable time. The H I properties of low-luminosity early-typegalaxies appear to be systematically different from those of many moreluminous early-type galaxies, and we suggest that these differences aredue to a different evolution of the two classes. The star formationhistory of these galaxies remains unclear. Their UBV colors and Hαemission-line strengths are consistent with having formed stars at aslowly declining rate for most of the past 1010 yr. If so,their star formation history would be intermediate between late-typespiral disks and giant elliptical galaxies. However, the current data donot rule out a small burst of recent star formation overlaid on an olderstellar population. Three of the galaxies have weak radio continuumemission, and the ratio of the far-infrared (FIR) to radio continuumemission is very similar to that of spirals of similar FIR or radioluminosity. We find that, except in the largest galaxy observed, theradio continuum emission can be accounted for solely by thermal(free-free) emission from H II regions, with no nonthermal (synchrotron)disk component. Thus, although these galaxies have gaseous disks, a diskmagnetic field may be very weak or absent. Based on observations withthe Australia Telescope Compact Array. The Australia Telescope is fundedby the Commonwealth of Australia for operation as a National Facilitymanaged by CSIRO.
| HI in early-type galaxies
We summarise the HI properties of early-type galaxies, in particular thedifferences in HI morphologies observed in early-type galaxies ofdifferent luminosities. We find that in low-luminosity early-typegalaxies the HI is almost always in a disk-like structure, with centralsurface densities high enough for star formation to occur. In a fewluminous early-type galaxies the HI is also in a disk or in a ring-likestructure, but in most luminous early-type galaxies the HI has arelatively irregular morphology. The surface densities in the HI disksin luminous early-type galaxies are lower than in the HI disks in low-luminosity early-type galaxies and no large-scale star formation shouldoccur in these disks. We discuss these different HI characteristics inthe context of other properties of early-type galaxies that correlatewith luminosity.
| 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 Montreal Blue Galaxy Survey.III.Third List of UV-Bright Candidates
We present and discuss the latest addition of the Montreal Blue Galaxy(MBG) survey. Inspection of 59 Curtis Schmidt plates resulted in theidentification of 135 new UV-bright galaxies with B < 15.5. Thisbrings the total number of MBGs to 469. New results of the V/V_m testshow that our survey is complete to B = 14.7. From our most recentspectroscopic follow-up, we confirm the discovery of one new Seyfert 1galaxy and possibly one new Seyfert 2 galaxy. We confirm also the biasof the MBG survey towards the low-excitation and metal rich StarburstNucleus Galaxies (SBNGs). The spectral characteristics of the MBGs aresimilar to those of the infrared luminous IRAS galaxies. As a commoncharacteristic, they show a mean ratio Log([NII]/Hα ) in excess of0.2 dex as compared to normal disk HII regions. In general, the MBGshave lower far-infrared luminosities (LIR < 10(11)Lsun) and are nearer (z < 0.05) than the luminous IRASgalaxies. The distribution of the morphologies of the MBGs indicates ahigh number of early-type spirals (Sb and earlier). Nearly half of thesegalaxies also possess a bar. In our sample, the fraction of galaxieswith bars depends on the morphology and increases towards the late-typespirals. However, if we consider only isolated galaxies, the late-typespirals show a clear tendency to be barred. Signs of a recentinteraction with neighbor galaxies are obvious only in 24% of ourcandidates. Although this number is only a lower limit, it isnevertheless sufficiently low to suggest that in a majority of massivegalaxies the burst of star formation do not depends solely on dynamicalprocesses.
| Low-luminosity radio sources in early-type galaxies
A sensitive radio continuum survey of 114 nearby E and S0 galaxies hasbeen made to search for weak sources. The radio detection rate is 42percent, with a flux limit of 0.8 mJy at 5 GHz. By deriving the radioluminosity function for a complete sample, it is shown that most brightearly-type galaxies have low-luminosity nonthermal radio sources.Galaxies of similar optical luminosity vary widely in radio luminosity,but a characteristic radio power rises roughly as the optical luminositysquared. S0 galaxies have weaker radio sources on average thanelliptical galaxies, but this can be explained by the low luminosity ofmost S0 bulges relative to ellipticals. No correlation is found betweenradio power and axial ratio for galaxies with radio luminosities below10 to the 23rd W/Hz.
| On the relationship between radio emission and optical properties in early-type galaxies
To study the origin of radio activity in early-type galaxies, thepossible dependence of their radio emission on basic optical parameters,such as the absolute magnitude, the central velocity dispersion sigma,and the mean surface brightness mu is explored. A sample of 743 E and SOgalaxies is used which is based on three independent radio surveys ofoptically selected galaxies with virtually complete information onmagnitudes, morphological types, redshift distances, diameters, andradio fluxes. For both E and SO galaxies, only the absolute magnitudeappears to be directly related to the radio activity, while sigma and mudo not. Also, a significant dependence of the apparent flattening onradio power is confirmed for E galaxies. Some relevant implications ofthese results are discussed.
| 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.
| Ionized gas in elliptical and S0 galaxies. I - A survey for H-alpha and forbidden N II emission
A spectroscopic survey of a large sample of southern E and S0 galaxiesin order to detect ionized gas in the nuclei is reported. The strongestline in the 6000-7000 A range was nearly always forbidden N II 6584 A,followed by H-alpha and forbidden S II 6716, 6731 A. Identical detectionrates of about 50 percent were obtained for the forbidden N II line inboth E and S0 galaxies. The mass of ionized gas in early-type galaxieswas very small, with values typically in the range 1000-10,000 solarmasses. The relative emission-line strengths in virtually every casewere indistinguishable from those of LINER nuclei. The observed valuesof the forbidden N II 6584 A/H-alpha ratios fell mostly between one andthree and seem correlated with galaxy absolute magnitude. The existenceof such a correlation may be indicative of metallicity differences.
| Southern Galaxy Catalogue.
Not Available
| Radio and optical observations of a complete sample of E and SO galaxies. III. A radio continuum survey at 2.7 and 5.0 GHz.
Abstract image available at:http://adsabs.harvard.edu/cgi-bin/nph-bib_query?1984AJ.....89...53S&db_key=AST
| Radio and optical observations of a complete sample of E and SO galaxies. II. UBV aperture photometry.
Abstract image available at:http://adsabs.harvard.edu/cgi-bin/nph-bib_query?1984AJ.....89...34S&db_key=AST
| Radio and optical observations of a complete sample of E and S0 galaxies. I - Radial velocities. II - UBV aperture photometry. III - A radio continuum survey at 2.7 and 5.0 GHz
Abstract image available at:http://adsabs.harvard.edu/cgi-bin/nph-bib_query?1984AJ.....89...23S&db_key=AST
| A sample of southern binary galaxies
Data for 29 pairs of galaxies below declination -32 deg are presentedand analyzed. Although the sample is small, there is some suggestion ofan extended mass distribution.
| On the variation of ellipticity with radius in elliptical galaxies
Ellipticity profiles and isophotal structures of 75 elliptical galaxieswith declinations south of approximately -23 deg are compared. Thesample studied includes both isolated ellipticals and members of pairs,multiplets, groups, and clusters. It is found that: (1) ellipticalgalaxies present four trends as a function of radius, viz., constant,peaked, decreasing, and increasing outward; (2) there is a correlationbetween ellipticity profile and membership in groups or clusters; (3)the brightest ellipticals in rich groups and compact clusters haveellipticity profiles that increase with radius; and (4) rotation of themajor axis of the isophotes is correlated with asymmetry of theisophotes, regardless of the class of ellipticity profile.
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