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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.
| Imaging of MBG starbursts - II. The nature of the sample
In this paper, broad-band imaging in BVRI is used in parallel withinformation from long-slit spectroscopy and IRAS data to study starformation processes in a sample of 15 MBG (Montreal blue galaxy)starbursts, in order to understand their nature more clearly. Most ofthese galaxies are early-type spirals with disturbed morphologies. Theburst of star formation is concentrated in the nucleus, extending to amean distance of 1.6 kpc from the centre. In the most active cases,ionized gas could be detected up to a substantial fraction of the radiusof the optical surface of the galaxy. We have found evidence suggestingthat the enhancement of star formation in our galaxies is correlated toa higher concentration of gas in the nucleus. No mechanism was clearlyidentified to explain the accretion of gas in this region. Even thoughwe see MBGs at different levels of activity and with differentmorphologies, they present similar characteristics in terms of starformation processes. The peculiar morphologies, the infraredcharacteristics and the net excess of gas in the MBGs compared withgalaxies of the same morphological type suggest that the bursts arerelated to some kind of interaction with other galaxies. We foundnear-constant star formation rates over a period of a few Gyr, which weinterpret as an indication of either long duration bursts (time-scale ofthe order 1Gyr) or a succession of shorter bursts. The concentration ofthe bursts into the circumnuclear regions and their importance in termsof masses of stars created suggest that this particular phenomenon couldrepresent an important phase in the evolution of these galaxies.
| Imaging of MBG starbursts - I. Morphological analysis
We present, in detail, the morphological analysis of a sample of 15galaxies of the Montreal blue galaxy (MBG) survey, based on BVRIimaging. The sample consists of starburst nucleus galaxies, mostly withearly-type morphologies. We fit elliptical isophotes to the images, andanalyse the parameters derived from the fitting procedure, theluminosity profiles, the B-I colour profiles and B-I colour maps.Circumnuclear regions of star formation are identified, correspondingwell to the extended Hα emission measured spectroscopically. Thedimensions of these extended regions are of the order of kiloparsecs.For barred galaxies, the star formation is more concentrated than forunbarred ones, which tend to have extended starbursts. A highinteraction rate for the objects studied is indicated by the frequencyof dust, twisted isophotes, and a wide dispersion of colours (similar toArp-Madore galaxies), which is not correlated with the morphologicaltype. The observed isophotal twists in our sample are related to thepresence of bars, for SBa and later types, or to geometrical decoupling,for S0 and E galaxies. The level of `boxiness' and `discyness' is largerthan that of normal early-type galaxies, reflecting the disturbedmorphology of these objects. The connection of these morphologicalcharacteristics with the observed starbursts is highly probable.
| Galaxies with f12 > f25
We have compiled a sample of galaxies whose flux density is higher at 12microns (f12) than at 25 microns (f25). It is argued thatf12 >f25effectively selects quiescent galaxies which are less active ininfrared, radio, and optical bands than other types of normal galaxies.Moreover galaxies withf12 >f25 do not exhibit the well-knownrelations that normal galaxies show between far-infrared parameters, forexample, the negative correlation betweenf12/f25 andf60/f100. Thesegalaxies also show different far-infrared and radio properties. In ouropinion this sample of quiescent galaxies is suitable for use as acontrol sample when properties of more active galaxies are discussed. Itmay also be used in modeling galaxies with active star formation or anactive nucleus.
| The extended 12 micron galaxy sample
We have selected an all-sky (absolute value of b greater than or equalto 25 deg) 12 micron flux-limited sample of 893 galaxies from the IRASFaint Source Catalog, Version 2 (FSC-2). We have obtained accurate totalfluxes in the IRAS wavebands by using the ADDSCAN procedure for allobjects with FSC-2 12 micron fluxes greater than 0.15 Jy and increasingflux densities from 12 to 60 microns, and defined the sample by imposinga survey limit of 0.22 Jy on the total 12 micron flux. Its completenessis verified, by means of the classical log N - log S andV/Vmax tests, down to 0.30 Jy, below which we have measuredthe incompleteness down to the survey limit, using the log N - log Splot, for our statistical analysis. We have obtained redshifts (mostlyfrom catalogs) for virtually all (98.4%) the galaxies in the sample.Using existing catalogs of active galaxies, we defined a subsample of118 objects consisting of 53 Seyfert 1s and quasars, 63 Seyfert 2s, andtwo blazars (approximately 13% of the full sample), which is the largestunbiased sample of Seyfert galaxies ever assembled. Since the 12 micronflux has been shown to be about one-fifth of the bolometric flux forSeyfert galaxies and quasars, the subsample of Seyferts (includingquasars and blazars) is complete not only to 0.30 Jy at 12 microns butalso with respect to a bolometric flux limit of approximately 2.0 x10-10 ergs/s/sq cm. The average value of V/Vmaxfor the full sample, corrected for incompleteness at low fluxes, is 0.51+/- 0.04, expected for a complete sample of uniformly distributedgalaxies, while the value for the Seyfert galaxy subsample is 0.46 +/-0.10. We have derived 12 microns and far-infrared luminosity functionsfor the AGNs, as well as for the entire sample. We extracted from oursample a complete subsample of 235 galaxies flux-limited (8.3 Jy) at 60microns. The 60 micron luminosity function computed for this subsampleis in satisfactory agreement with the ones derived from the brightgalaxy sample (BGS) and the deep high-galactic latitude sample, bothselected at 60 microns.
| The Montreal blue galaxy survey. I - First list of ultraviolet-bright candidates
The first results of a UV-bright galaxy survey using theMontreal-Cambridge-Tololo (MCT) plate collection are presented. Visualinspection of 57 CTIO Curtis Schmidt plates, cnvering more than 1300 sqdeg, has resulted in the identification of 95 UV-bright galaxiesbrighter than B = 15.5. Even though 80 percent of these objects are IRASsources, barely 20 percent have their nature already established. Theinitial result of our survey shows that the bulk of our UV-brightcandidates are narrow emission-line galaxies commonly known as starburstor H II galaxies. The fraction of AGNs found is somewhat less than 10percent, but comparable to what has been found by the Markarian survey.
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