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The AMIGA sample of isolated galaxies. VI. Radio continuum properties of isolated galaxies: a very radio-quiet sample
Context: This paper is part of a series that describes the results ofthe AMIGA (Analysis of the interstellar Medium of Isolated GAlaxies)project, studying the largest sample of very isolated galaxies in thelocal Universe. Aims: The study of the radio properties of the AMIGAsample is intended to characterize the radio continuum emission for asample least affected by the local environment, thus providing areference against which less isolated and interacting samples can becompared. Methods: Radio continuum data at 325, 1420, and 4850 MHzwere extracted from the WENSS, NVSS/FIRST, and GB6 surveys,respectively. The source extractions have been obtained fromreprocessing the data and new detections added to the cross-matcheddetections with the respective survey catalogs. We focus on the completeAMIGA subsample composed of 719 galaxies. Results: A catalog of radiofluxes was obtained from the above four surveys. Comparison between theNVSS and FIRST detections indicates that the radio continuum is comingfrom disk-dominated emission in spiral galaxies, in contrast to theresults found in high-density environments where nuclear activity ismore frequent. The comparison of the radio continuum power with acomparable sample, which is however not selected with respect to itsenvironment, the Condon et al. UGC-SF sample of starforming fieldgalaxies, shows a lower mean value for the AMIGA sample. We haveobtained radio-to-optical flux ratios (R) using the NVSS radio continuumflux. The distribution of R for the AMIGA galaxies is consistent with asample dominated by radio emission from star formation (SF) and a smallnumber of active galactic nuclei (AGN), with less than 3% of the samplewith R > 100. We derived the radio luminosity function (RLF) andtotal power density of the radio continuum emission for the AMIGA sampleat 1.4 GHz, and compared them with results from other low-redshiftstudies. The Schechter fit of the RLF indicates a major weight of thelow-luminosity galaxies. Conclusions: The results indicate the verylow level of radio continuum emission in our sample of isolatedgalaxies, which is dominated by mild disk SF. It confirms thus the AMIGAsample as a suitable template to effectively quantify the role ofinteractions in samples extracted from denser environments.Full Table 2 is only available in electronic form at the CDS viaanonymous ftp to cdsarc.u-strasbg.fr (130.79.128.5) or viahttp://cdsweb.u-strasbg.fr/cgi-bin/qcat?J/A+A/485/475
| The AMIGA sample of isolated galaxies. V. Quantification of the isolation
Context: The AMIGA project aims to build a well defined andstatistically significant reference sample of isolated galaxies in orderto estimate the environmental effects on the formation and evolution ofgalaxies. Aims: The goal of this paper is to provide a measure of theenvironment of the isolated galaxies in the AMIGA sample, quantifyingthe influence of the candidate neighbours identified in our previouswork and their potential effects on the evolution of the primarygalaxies. Here we provide a quantification of the isolation degree ofthe galaxies in this sample. Methods: Our starting sample is theCatalogue of Isolated Galaxies (CIG). We used two parameters to estimatethe influence exerted by the neighbour galaxies on the CIG galaxy: thelocal number density of neighbour galaxies and the tidal strengthaffecting the CIG galaxy. We show that both parameters together providea comprehensive picture of the environment. For comparison, thoseparameters have also been derived for galaxies in denser environmentssuch as triplets, groups and clusters. Results: The CIG galaxies show acontinuous spectrum of isolation, as quantified by the two parameters,from very isolated to interacting. The fraction of CIG galaxies whoseproperties are expected to be influenced by the environment is howeverlow (159 out of 950 galaxies). The isolated parameters derived for thecomparison samples gave higher values than for the CIG and we foundclear differences for the average values of the 4 samples considered,proving the sensitivity of these parameters. Conclusions: Theenvironment of the galaxies in the CIG has been characterised, using twocomplementary parameters quantifying the isolation degree, the localnumber density of the neighbour galaxies and the tidal forces affectingthe isolated galaxies. A final catalogue of galaxies has been producedand the most isolated of these galaxies are consequently appropriate toserve as a reference sample for the AMIGA project.Full Tables [see full text], [see full text] and [see full text]-[see full text] are available in electronic form at the CDS via anonymous ftp tocdsarc.u-strasbg.fr (130.79.128.5) or viahttp://cdsweb.u-strasbg.fr/cgi-bin/qcat?J/A+A/472/121 and fromhttp://www.iaa.es/AMIGA.html.
| The AMIGA sample of isolated galaxies. III. IRAS data and infrared diagnostics
Aims.We describe the mid- (MIR) and far- (FIR) infrared properties of alarge (~1000) sample of the most isolated galaxies in the localUniverse. This sample is intended as a "nurture-free" zero point againstwhich more environmentally influenced samples can be compared. Methods: We reprocess IRAS MIR/FIR survey data using the ADDSCAN/SCANPIutility for 1030 out of 1050 galaxies from the Catalogue of IsolatedGalaxies (CIG) as part of the AMIGA project. We focus on diagnostics(FIR luminosity L_FIR, R=log(L_FIR/LB), and IRAS colours)thought to be sensitive to effects of environment or interaction. Results: The distribution of log(L_FIR) sharply peaks from 9.0-10.5,with very few (<2%) galaxies above 10.5. Review of available opticalimages of the most FIR luminous galaxies finds the majority likely to beinteracting systems missed in our earlier morphological reevaluation.The optically normalised luminosity diagnostic R=log(L_FIR/LB) shows a sharply peaked distribution between 0.0and -1.0. These results were compared to the magnitude limited sample ofthe Center for Astrophysics that was selected without environmentaldiscrimination. This modestly (e.g., compared to cluster, binary galaxy,and compact group samples) environmentally affected sample shows asignificantly higher mean log(L_FIR), and R, whereas the meanlog(LB) is the same. Our sample shows a strong L_FIR vs.LB correlation, with a slope steeper than one (L_FIR ∝LB1.41). Interacting galaxies were found abovethis correlation, showing an enhancement in L_FIR. With respect to theIRAS colours, we found higher F_60/F_100 values for ellipticals andlate-type galaxies than for spirals, indicating a higher dusttemperature. The mean value of F_60/F_100 was found to be lower than forinteracting samples from the literature. Conclusions: .The resultsindicate that the FIR emission is a variable enhanced by interaction,and that our sample probably shows the lowest possible mean value. Thisattests to the utility of our sample for defining a nurture-free zeropoint.
| The AMIGA sample of isolated galaxies. II. Morphological refinement
We present a refinement of the optical morphologies for galaxies in theCatalog of Isolated Galaxies that forms the basis of the AMIGA (Analysisof the interstellar Medium of Isolated GAlaxies) project. Uniformreclassification using the digitized POSS II data benefited from thehigh resolution and dynamic range of that sky survey. Comparison withindependent classifications made for an SDSS overlap sample of more than200 galaxies confirms the reliability of the early vs. late-typediscrimination and the accuracy of spiral subtypes within Δ T =1-2. CCD images taken at the Observatorio de Sierra Nevada were alsoused to solve ambiguities in early versus late-type classifications. Aconsiderable number of galaxies in the catalog (n = 193) are flagged forthe presence of nearby companions or signs of distortion likely due tointeraction. This most isolated sample of galaxies in the local Universeis dominated by two populations: 1) 82% are spirals (Sa-Sd) with thebulk being luminous systems with small bulges (63% between types Sb-Sc)and 2) a significant population of early-type E-S0 galaxies (14%). Mostof the types later than Sd are low luminosity galaxies concentrated inthe local supercluster where isolation is difficult to evaluate. Thelate-type spiral majority of the sample spans a luminosity rangeMB-corr = -18 to -22 mag. Few of the E/S0 population are moreluminous than -21.0 marking the absence of the often-sought superL* merger (e.g. fossil elliptical) population. The rarity ofhigh luminosity systems results in a fainter derived M* forthis population compared to the spiral optical luminosity function(OLF). The E-S0 population is from 0.2 to 0.6 mag fainter depending onhow the sample is defined. This marks the AMIGA sample as unique amongsamples that compare early and late-type OLFs separately. In othersamples, which always involve galaxies in higher density environments,M^*_E/S0 is almost always 0.3-0.5 mag brighter than M^*_S, presumablyreflecting a stronger correlation between M* andenvironmental density for early-type galaxies.
| The ISOPHOT 170 μm Serendipity Survey II. The catalog of optically identified galaxies%
The ISOPHOT Serendipity Sky Survey strip-scanning measurements covering≈15% of the far-infrared (FIR) sky at 170 μm were searched forcompact sources associated with optically identified galaxies. CompactSerendipity Survey sources with a high signal-to-noise ratio in at leasttwo ISOPHOT C200 detector pixels were selected that have a positionalassociation with a galaxy identification in the NED and/or Simbaddatabases and a galaxy counterpart visible on the Digitized Sky Surveyplates. A catalog with 170 μm fluxes for more than 1900 galaxies hasbeen established, 200 of which were measured several times. The faintest170 μm fluxes reach values just below 0.5 Jy, while the brightest,already somewhat extended galaxies have fluxes up to ≈600 Jy. For thevast majority of listed galaxies, the 170 μm fluxes were measured forthe first time. While most of the galaxies are spirals, about 70 of thesources are classified as ellipticals or lenticulars. This is the onlycurrently available large-scale galaxy catalog containing a sufficientnumber of sources with 170 μm fluxes to allow further statisticalstudies of various FIR properties.Based on observations with ISO, an ESA project with instruments fundedby ESA Member States (especially the PI countries: France, Germany, TheNetherlands and the UK) and with the participation of ISAS and NASA.Members of the Consortium on the ISOPHOT Serendipity Survey (CISS) areMPIA Heidelberg, ESA ISO SOC Villafranca, AIP Potsdam, IPAC Pasadena,Imperial College London.Full Table 4 and Table 6 are only available in electronic form at theCDS via anonymous ftp to cdsarc.u-strasbg.fr (130.79.128.5) or viahttp://cdsweb.u-strasbg.fr/cgi-bin/qcat?J/A+A/422/39
| The 2MASS-selected Flat Galaxy Catalog
An all-sky catalog of 18020 disc-like galaxies is presented. Thegalaxies are selected from the Extended Source Catalog of the Two MicronAll-Sky Survey (XSC 2MASS) basing on their 2MASS axial ratio a/b ≥ 3.The Catalog contains data on magnitudes of a galaxy in the J, H,KS bands, its axial ratio, positional angle, index ofluminosity concentration, as well as identification of the galaxy withthe LEDA and the NED databases. Unlike the available optical catalogs,the new 2MFGC catalog seems to be more suitable to study cosmicstreaming on a scale of z <~ 0.1. The dipole moment of distributionof the bright (K < 11m) 2MFGC objects (l = 227°, b =41° or SGL = 90°, SGB = -43°) lies within statistical errors(±15°) in the direction of the IRAS dipole and the opticalRFGC dipole.
| Revised positions for CIG galaxies
We present revised positions for the 1051 galaxies belonging to theKarachentseva Catalog of Isolated Galaxies (CIG). New positions werecalculated by applying SExtractor to the Digitized Sky Survey CIG fieldswith a spatial resolution of 1 arcsper 2. We visually checked theresults and for 118 galaxies had to recompute the assigned positions dueto complex morphologies (e.g. distorted isophotes, undefined nuclei,knotty galaxies) or the presence of bright stars. We found differencesbetween older and newer positions of up to 38 arcsec with a mean valueof 2 arcsper 96 relative to SIMBAD and up to 38 arcsec and 2 arcsper 42respectively relative to UZC. Based on star positions from the APMcatalog we determined that the DSS astrometry of five CIG fields has amean offset in (alpha , delta ) of (-0 arcsper 90, 0 arcsper 93) with adispersion of 0 arcsper 4. These results have been confirmed using the2MASS All-Sky Catalog of Point Sources. The intrinsic errors of ourmethod combined with the astrometric ones are of the order of 0 arcsper5.Full Table 1 is only available in electronic form at the CDS viaanonymous ftp to cdsarc.u-strasbg.fr (130.79.128.5) or viahttp://cdsweb.u-strasbg.fr/cgi-bin/qcat?J/A+A/411/391
| 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.
| Northern dwarf and low surface brightness galaxies. II - The Green Bank neutral hydrogen survey
The paper reports neutral hydrogen observations of a large sample ofdwarf and other low surface brightness galaxies. A detailed discussionand error analysis of the observations are presented, and spectra aredisplayed for 329 galaxies detected for the first time, or detected withsubstantially better signal-to-noise ratios than achieved previously.The positions on the sky of 667 galaxies meeting the present selectioncriteria north of delta = 38 deg are shown. The distribution of theredshifts of galaxies detected at Green Bank is illustrated. The GreenBank detections tapered off strongly below the median H I flux of 3.7 Jykm/s detected at Arecibo: only 12 percent of the Green Bank sample wasdetected with smaller fluxes.
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