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An IRAS High Resolution Image Restoration (HIRES) Atlas of All Interacting Galaxies in the IRAS Revised Bright Galaxy Sample
The importance of far-infrared observations for our understanding ofextreme activity in interacting and merging galaxies has beenillustrated by many studies. Even though two decades have passed sinceits launch, the most complete all-sky survey to date from which far-IRselected galaxy samples can be chosen is still that of the InfraredAstronomical Satellite (IRAS). However, the spatial resolution of theIRAS all-sky survey is insufficient to resolve the emission fromindividual galaxies in most interacting galaxy pairs, and hence previousstudies of their far-IR properties have had to concentrate either onglobal system properties or on the properties of very widely separatedand weakly interacting pairs. Using the HIRES image reconstructiontechnique, it is possible to achieve a spatial resolution ranging from30" to 1.5m (depending on wavelength and detector coverage), whichis a fourfold improvement over the normal resolution of IRAS. This issufficient to resolve the far-IR emission from the individual galaxiesin many interacting systems detected by IRAS, which is very importantfor meaningful comparisons with single, isolated galaxies. We presenthigh-resolution 12, 25, 60, and 100 μm images of 106 interactinggalaxy systems contained in the IRAS Revised Bright Galaxy Sample (RBGS,Sanders et al.), a complete sample of all galaxies having a 60 μmflux density greater than 5.24 Jy. These systems were selected to haveat least two distinguishable galaxies separated by less than threeaverage galactic diameters, and thus we have excluded very widelyseparated systems and very advanced mergers. Additionally, some systemshave been included that are more than three galactic diameters apart,yet have separations less than 4' and are thus likely to suffer fromconfusion in the RBGS. The new complete survey has the same propertiesas the prototype survey of Surace et al. We find no increased tendencyfor infrared-bright galaxies to be associated with other infrared-brightgalaxies among the widely separated pairs studied here. We find smallenhancements in far-IR activity in multiple galaxy systems relative toRBGS noninteracting galaxies with the same blue luminosity distribution.We also find no differences in infrared activity (as measured byinfrared color and luminosity) between late- and early-type spiralgalaxies.
| Luminous Infrared Galaxies. III. Multiple Merger, Extended Massive Star Formation, Galactic Wind, and Nuclear Inflow in NGC 3256
We report detailed evidence for multiple merger, extended massive starformation, galactic wind, and circular/noncircular motions in theluminous infrared galaxy NGC 3256, based on observations ofhigh-resolution imaging (Hubble Space Telescope, ESO NTT), and extensivespectroscopic data (more than 1000 spectra, collected at EstaciónAstrofísica de Bosque Alegre, Complejo Astronómico elLeoncito, Cerro Tololo InterAmerican Observatory, and IUEobservatories). We find in a detailed morphological study (resolution~15 pc) that the extended massive star formation process detectedpreviously in NGC 3256 shows extended triple asymmetrical spiral arms(r~5 kpc), emanating from three different nuclei. The main opticalnucleus shows a small spiral disk (r~500 pc), which is a continuation ofthe external one and reaches the very nucleus. The core shows blueelongated structure (50 pc×25 pc) and harbors a blue stellarcluster candidate (r~8 pc). We discuss this complex morphology in theframework of an extended massive star formation driven by a multiplemerger process (models of Hernquist et al. and Taniguchi et al.). Westudy the kinematics of this system and present a detailed Hαvelocity field for the central region(40''×40'' rmax~30''~5kpc), with a spatial resolution of 1" and errors of +/-15 kms-1. The color and isovelocity maps show mainly (1) akinematic center of circular motion with ``spider'' shape, locatedbetween the main optical nucleus and the close (5") mid-IR nucleus and(2) noncircular motions in the external parts. We obtained three``sinusoidal rotation curves'' (from the Hα velocity field) aroundposition angle (P.A.) ~55°, ~90°, and ~130°. In the mainoptical nucleus we found a clear ``outflow component'' associated withgalactic winds plus an ``inflow radial motion.'' The outflow componentwas also detected in the central and external regions (r<=5-6 kpc).The main axis of the inflow region (P.A.~80deg) ispractically perpendicular to the ouflow axis (atP.A.~160deg). We analyze in detail the physical conditions inthe giant H II regions located in the asymmetric spiral arms, the twomain optical nuclei, and the outflow component (using long-slitspectroscopy, plus standard models of photoionization, shocks, andstarbursts). We present four detailed emission-line ratios (NII/Hα, S II/Hα, S II/S II), and FWHM (Hα) maps for thecentral region (30''×30''rmax~22''~4 kpc), with a spatial resolution of 1".In the central region (r~5-6 kpc) we detected that the nuclear starburstand the extended giant H II regions (in the spiral arms) have verysimilar properties, i.e., high metallicity and low-ionization spectra,with Teff=35,000 K, solar abundance, a range ofTe~6000-7000 K, and Ne~100-1000 cm-3.The nuclear and extended outflow shows properties typical of galacticwind/shocks, associated with the nuclear starburst. We suggest that theinteraction between dynamical effects, the galactic wind (outflow),low-energy cosmic rays, and the molecular+ionized gas (probably in theinflow phase) could be the possible mechanism that generate the``similar extended properties in the massive star formation, at a scaleof 5-6 kpc!'' We have also studied the presence of the closemerger/interacting systems NGC 3256C (at ~150 kpc, ΔV=-100 kms-1) and the possible association between the NGC 3256 and3263 groups of galaxies. In conclusion, these results suggest that NGC3256 is the product of a multiple merger, which generated an extendedmassive star formation process with an associated galactic wind plus anuclear inflow. Therefore, NGC 3256 is another example in which therelation between mergers and extreme starburst (and the powerfulgalactic wind, ``multiple'' Type II supernova explosions) play animportant role in the evolution of galaxies (the hypothesis of Rieke etal., Joseph et al., Terlevich et al., Heckman et al., and Lípariet al.). Based on observations obtained at the Hubble Space Telescope(HST; Wide Field Planetary Camera 2 [WFPC2] and NICMOS) satellite;International Ultraviolet Explorer (IUE) satellite; European SouthernObservatory (ESO, NTT); Chile, Cerro Tololo Inter-American Observatory(CTIO), Chile; Complejo Astronómico el Leoncito (CASLEO),Argentina; Estación Astrofísica de Bosque Alegre(BALEGRE), Argentina.
| Nearby Active and Starburst Galaxies as Seen with ISOCAM
We present a set of spectral characteristics distinguishing opticallyselected active galactic nuclei (AGNs) from starbursts in the mid-IR. InAGN spectra, the Unidentified Infrared Bands (UIBs) are not detectedwhich is probably due to the destruction of their carriers by the UV-Xradiation field. In addition, a non-negligible continuum below 10 μmcommonly associated with emission from very hot dust is exclusivelypresent in AGNs. On the contrary, starburst spectra present clearlydetected UIBs with a faint underlying continuum between 5-10 μm.Based on these features, we build a mid-IR diagnostic diagram toidentify emission induced by the AGN and that associated with the starformation activity. This diagnostic based on the mid-IR continuum andthe UIB intensity allows us to estimate the relative importance of thethree components (HII regions, photo-dissociation regions (PDRs), andAGN) contained in the integrated mid-IR emission of galaxies. Ourdiagnostic diagram can be applied to reveal the presence of veryobscured active nuclei behind large columns of dust.
| 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 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.
| General study of group membership. II - Determination of nearby groups
We present a whole sky catalog of nearby groups of galaxies taken fromthe Lyon-Meudon Extragalactic Database. From the 78,000 objects in thedatabase, we extracted a sample of 6392 galaxies, complete up to thelimiting apparent magnitude B0 = 14.0. Moreover, in order to considersolely the galaxies of the local universe, all the selected galaxieshave a known recession velocity smaller than 5500 km/s. Two methods wereused in group construction: a Huchra-Geller (1982) derived percolationmethod and a Tully (1980) derived hierarchical method. Each method gaveus one catalog. These were then compared and synthesized to obtain asingle catalog containing the most reliable groups. There are 485 groupsof a least three members in the final catalog.
| Southern Galaxy Catalogue.
Not Available
| UBV photometry of 262 southern galaxies
Multiaperture photometry of 262 bright southern galaxies in the JohnsonUBV system is given. Most of these are south of -30 deg declination,although some northward to -10 deg are included. A total of 169 objectshave published radial-velocity determinations. These provide distancesand enable construction of color-magnitude diagrams for this subset ofobjects through a physical diameter of 2.0 kpc (with H = 100). Thetwo-color diagrams for the inner regions of the galaxies differ fromthose of integrated galaxies due to the color changes towards theircenters. Comparison with theoretical models of Larson and Tinsley (1978)suggest that the colors of the inner portions of most ellipticals andlenticulars are consistent with their having all stars formed at nearlyone epoch with little subsequent star formation, while for spiralslarger amounts of star formation, either in bursts or continuously, aresuggested. This simple picture is complicated by the presence of certainobjects having peculiar colors indicative of large amounts of recentstar formation.
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