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|The gas content of peculiar galaxies: Strongly interacting systems|
A study of the gas content in 1038 interacting galaxies, essentiallyselected from Arp, Arp & Madore, Vorontsov-Velyaminov catalogues andsome of the published literature, is presented here. The data on theinterstellar medium have been extracted from a number of sources in theliterature and compared with a sample of 1916 normal galaxies. The meanvalues for each of the different ISM tracers (FIR, 21 cm, CO lines,X-ray) have been estimated by means of survival analysis techniques, inorder to take into account the presence of upper limits. From the datait appears that interacting galaxies have a higher gas content thannormal ones. Galaxies classified as ellipticals have both a dust and gascontent one order of magnitude higher than normal. Spirals have in mostpart a normal dust and HI content but an higher molecular gas mass. TheX-ray luminosity also appears higher than that of normal galaxies ofsame morphological type, both including or excluding AGNs. We consideredthe alternative possibilities that the molecular gas excess may derivefrom the existence of tidal torques which produce gas infall from thesurrounding regions or from a different metallicity which affects the Xconversion factor between the observed CO line luminosity and the H_2calculated mass. According to our tests, it appears that interactinggalaxies possess a higher molecular mass than normal galaxies but with asimilar star formation efficiency.Table 1 is only available in electronic form at the CDS via anonymousftp to cdsarc.u-strasbg.fr (184.108.40.206) or viahttp://cdsweb.u-strasbg.fr/cgi-bin/qcat?J/A+A/422/941
|Galaxy interactions - poor starburst triggers. III. A study of a complete sample of interacting galaxies|
We report on a study of tidally triggered star formation in galaxiesbased on spectroscopic/photometric observations in the optical/near-IRof a magnitude limited sample of 59 systems of interacting and merginggalaxies and a comparison sample of 38 normal isolated galaxies. From astatistical point of view the sample gives us a unique opportunity totrace the effects of tidally induced star formation. In contrast toresults from previous investigations, our global UBV colours do notsupport a significant enhancement of starforming activity in theinteracting/merging galaxies. We also show that, contrary to previousclaims, there is no significantly increased scatter in the colours ofArp galaxies as compared to normal galaxies. We do find support formoderate (a factor of ~ 2-3) increase in star formation in the verycentres of the interacting galaxies of our sample, contributingmarginally to the total luminosity. The interacting and in particularthe merging galaxies are characterized by increased far infrared(hereafter FIR) luminosities and temperatures that weakly correlate withthe central activity. The LFIR/LB ratio however,is remarkably similar in the two samples, indicating that truestarbursts normally are not hiding in the central regions of the FIRluminous cases. The gas mass-to-luminosity ratio in optical-IR ispractically independent of luminosity, lending further support to thepaucity of true massive starburst galaxies triggered byinteractions/mergers. We estimate the frequency of such cases to be ofthe order of ~ 0.1% of the galaxies in an apparent magnitude limitedsample. Our conclusion is that interacting and merging galaxies, fromthe global star formation aspect, generally do not differ dramaticallyfrom scaled up versions of normal, isolated galaxies. No drastic changewith redshift is expected. One consequence is that galaxy formationprobably continued over a long period of time and did not peak at aspecific redshift. The effects of massive starbursts, like blowoutscaused by superwinds and cosmic reionization caused by starburstpopulations would also be less important than what is normally assumed.Based on observations collected at the European Southern Observatory, LaSilla, Chile.
|The K-band luminosity function of nearby field galaxies|
We present a measurement of the K-band luminosity function (LF) of fieldgalaxies obtained from near-infrared imaging of a sample of 345 galaxiesselected from the Stromlo-APM Redshift Survey. The LF is reasonably wellfitted over the 10-mag range -26<=MK<=-16 by aSchechter function with parameters α=-1.16+/-0.19,M*=-23.58+/-0.42 and φ*=0.012+/-0.008Mpc-3, assuming aHubble constant of H0=100kms-1Mpc-1. Wehave also estimated the LF for two subsets of galaxies subdivided by theequivalent width of the Hα emission line atEW(Hα)=10Å. There is no significant difference in LF shapebetween the two samples, although there is a hint (~1σsignificance) that emission-line galaxies (ELGs) have M* roughly 1magfainter than non-ELGs. Contrary to the optical LF, there is nodifference in faint-end slope α between the two samples.
|The Southern Sky Redshift Survey|
We report redshifts, magnitudes, and morphological classifications for5369 galaxies with m_B <= 15.5 and for 57 galaxies fainter than thislimit, in two regions covering a total of 1.70 sr in the southerncelestial hemisphere. The galaxy catalog is drawn primarily from thelist of nonstellar objects identified in the Hubble Space TelescopeGuide Star Catalog (GSC). The galaxies have positions accurate to ~1"and magnitudes with an rms scatter of ~0.3 mag. We compute magnitudes(m_SSRS2) from the relation between instrumental GSC magnitudes and thephotometry by Lauberts & Valentijn. From a comparison with CCDphotometry, we find that our system is homogeneous across the sky andcorresponds to magnitudes measured at the isophotal level ~26 magarcsec^-2. The precision of the radial velocities is ~40 km s^-1, andthe redshift survey is more than 99% complete to the m_SSRS2 = 15.5 maglimit. This sample is in the direction opposite that of the CfA2; incombination the two surveys provide an important database for studies ofthe properties of galaxies and their large-scale distribution in thenearby universe. Based on observations obtained at Cerro TololoInter-American Observatory, National Optical Astronomy Observatories,operated by the Association of Universities for Research in Astronomy,Inc., under cooperative agreement with the National Science Foundation;Complejo Astronomico El Leoncito, operated under agreement between theConsejo Nacional de Investigaciones Científicas de laRepública Argentina and the National Universities of La Plata,Córdoba, and San Juan; the European Southern Observatory, LaSilla, Chile, partially under the bilateral ESO-ObservatórioNacional agreement; Fred Lawrence Whipple Observatory;Laboratório Nacional de Astrofísica, Brazil; and the SouthAfrican Astronomical Observatory.
|Kinematics of the local universe. VII. New 21-cm line measurements of 2112 galaxies|
This paper presents 2112 new 21-cm neutral hydrogen line measurementscarried out with the meridian transit Nan\c cay radiotelescope. Amongthese data we give also 213 new radial velocities which complement thoselisted in three previous papers of this series. These new measurements,together with the HI data collected in LEDA, put to 6 700 the number ofgalaxies with 21-cm line width, radial velocity, and apparent diameterin the so-called KLUN sample. Figure 5 and Appendices A and B forcorresponding comments are available in electronic form at thehttp://www.edpsciences.com
|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.
|CO and HI in a southern sample of interacting galaxies. I. The data|
Using SEST, the Parkes antenna and the Australia Telescope CompactArray, we have made a survey of the ^12CO(1-0) and HI emission of anoptically-selected sample of ~60 southern interacting and merginggalaxies. In this paper we present the data and determine global massesof neutral gas (in molecular and atomic form) for the observed galaxies.We have detected HI in 26 systems and found that these galaxies haveless than 15% of their gas in molecular form. Figure 3 in its entirelyis only available in electronic form at CDS via anonymous ftp tocdsarc.u-strasbg.fr (220.127.116.11) or viahttp://cdsweb.u-strasbg.fr/Abstract.html
|The Stromlo-APM Redshift Survey. IV. The Redshift Catalog|
The Stromlo-APM Redshift Survey consists of 1797 galaxies with b_J_ <17.15 selected randomly at a rate of 1 in 20 from automated platemeasurement (APM) scans. The survey covers a solid angle of 1.3 sr (4300deg^2^) in the south Galactic cap. Redshifts have been measured for 1790(99.6%) of the galaxies. The median galaxy recession velocity is 15,300km s^-1^, and so the volume probed is V ~ 1.38 x 10^6^ h^-3^ Mpc^3^. Inthis paper we describe the construction of the redshift catalog andpresent the survey data.
|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 study of a complete sample of interacting galaxies. II. Images, colour distributions and spectra.|
We present broadband images, two-colour maps and spectra of a magnitudelimited sample of interacting and merging galaxies.
|Southern Sky Redshift Survey - The catalog|
The catalog of radial velocities for galaxies which comprise thediameter-limited sample of the Southern Sky Redshift Survey ispresented. It consolidates the data of observations carried out at theLas Campanas Observatory, Observatorio Nacional, and South AfricanAstronomical Observatory. The criteria used for the sample selection aredescribed, as well as the observational procedures and the techniqueutilized to obtain the final radial velocities. The intercomparisonbetween radial velocity measurements from different telescopes indicatesthat the final data base is fairly homogeneous with a typical error ofabout 40 km/s. The sample is at present 90 percent complete, and themissing galaxies are predominantly objects with very low surfacebrightness for which it is very difficult to obtain optical redshifts.
|A study of a complete sample of interacting galaxies. I - Presentation of the sample and the UBVRIJHK photometry|
An investigation is presented on what effects galaxy-galaxy interactionhas on the properties of the involved galaxies. A magnitude limitedsample of interacting galaxies is presented, together with a controlsample of isolated galaxies. The Cousins UBVRI and Johnson JHKphotometry of all galaxies included in the samples is also presented.
|The ON-CfA redshift survey of the southern hemisphere|
A redshift survey of a diameter-limited sample of southern galaxies hasbeen performed by the Observatorio Nacional in collaboration with theHarvard-Smithsonian Center for Astrophysics. Redshift data are presentedfor 442 galaxies. A relatively small mean difference of -5.2 km/s wasfound between the present redshifts and previous radio data.
|Heard above the hubbub.|
|Southern Galaxy Catalogue.|
|The very large, interacting galaxy pair IC 5174/75|
The interacting galaxy pair IC 5174/75 has drawn attention, due to anangular size for IC 5174 that is disproportionate to its brightness. Apreliminary investigation of this peculiar system is given, based on twoESO Schmidt plates and digital spectra of the two galaxies. At aredshift of 0.036, the system measures about 320 kpc, and the two longouter arms of IC 5174 measure approximately 300 kpc. It is suggestedthat the present morphology of the system is the result of a recentencounter, and may be qualitatively similar to the M51+NGC 5195 systemwhen viewed edge-on despite differences of absolute size.
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