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Supernovae 2005ds, 2005em, 2005er, 2005es, 2005et, 2005eu
IAUC 8611 available at Central Bureau for Astronomical Telegrams.
| Supernovae 2005eq, 2005er, and 2005es
IAUC 8608 available at Central Bureau for Astronomical Telegrams.
| Implications for unified schemes from the quasar fraction and emission-line luminosities in radio-selected samples
We use a principal components analysis of radio-selected (3CRR, 6CE and7CRS) active galactic nuclei (AGN) data sets to define two parametersrelated to low-frequency (151-MHz) radio luminosity L151 and[OIII] luminosity L[OIII]: a parameter α encoding theL151-L[OIII] correlation and a parameter βencoding scatter about this correlation. We describe methods forconstructing generalized luminosity functions (GLFs) based on α,β, redshift and schemes for unifying quasars and radio galaxies.These GLFs can be used to generate radio luminosity functions (RLFs)which improve on those of Willott et al. (2001a), mostly because theyincorporate scatter and are therefore much smoother.Luminosity-dependent unified schemes (e.g. a receding-torus scheme) havebeen invoked to explain the low quasar-to-radio galaxy fraction at lowα and the differences in emission-line luminosities of radioquasars and radio galaxies. With the constraints of the 3CRR, 6CE and7CRS data sets and radio source counts, our GLF approach was used todetermine whether a receding-torus-like scheme is required if there aretwo populations of radio sources: one at low α, consisting of`starved AGN' the other at high α, consisting of `Eddington-tunedAGN'. Because of the overlap between these two populations and theeffects of the β parameter, schemes with or without a recedingtorus can produce a low quasar fraction at low α and differencesin [OIII] luminosity between radio galaxies and quasars. The recedingtorus may be a physical process important in one or more populations ofradio sources, but this is not yet proved either by the quasar fractionor the emission-line properties of radio-selected samples.
| The VSOP 5 GHz Active Galactic Nucleus Survey. IV. The Angular Size/Brightness Temperature Distribution
The VLBI Space Observatory Programme (VSOP) mission is a Japanese-ledproject to study radio sources with submilliarcsecond angularresolution, using an orbiting 8 m telescope on board the satellite HALCAwith a global Earth-based array of telescopes. A major program is the 5GHz VSOP Survey Program, which we supplement here with Very LongBaseline Array observations to produce a complete and fluxdensity-limited sample. Using statistical methods of analysis of theobserved visibility amplitude versus projected (u, v) spacing, we havedetermined the angular size and brightness temperature distribution ofbright radio emission from active galactic nuclei. On average, the coreshave a diameter (full width, half-power) of 0.20 mas, which containsabout 20% of the total source emission, and 14%+/-6% of the cores areless than 0.04 mas in size. About 20%+/-5% of the radio cores have asource frame brightness temperatureTb>1.0×1013 K, and 3%+/-2% haveTb>1.0×1014 K. A model of the highbrightness temperature tail suggests that the radio cores havebrightness temperatures ~1×1012 K and are beamed towardthe observer with an average bulk motion of β=0.993+/-0.004.
| Spectra, optical identifications, and statistics of a complete sample of radio sources at declinations 10° 12°30′
The results of 0.97, 2.3, 3.9, 7.7, 11.1, and 21.7 GHz observations of acomplete sample of radio sources obtained on the RATAN-600 radiotelescope are presented. The sample is comprised of sources from the4.85-GHz MGB survey, and contains all sources at declinations 10°12°30′ (J2000) with Galactic latitudes |b|>15° and fluxdensities S 4.85>200 mJy. Optical identifications have been obtainedfor about 86% of the radio sources with flat spectra and 59% of thosewith steep spectra. The spectra of the flat-spectrum sources have beendecomposed into extended and compact components.
| 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
| Optical emission-line spectra from jet-cloud collisions?
We have examined the relative emission line strengths of [NII], [OI],and [SII] for selected regions in three nearby objects, all of whichhave published radio images showing detailed correspondence between thedisrupted morphology of the ionized gas clouds and the radio features atspatial resolutions of <=1h-1 kpc. In all of these casesthe clouds have measured velocities which differ from those of theambient medium and are directed away from the impinging radio plasma. Intwo of these objects the values for [NII]:H/α are significantlylower than those usually found for active galaxy nuclei (and EELG) withsimilar values of [OI] and [SII]. None of the published models whichcalculate emission line ratios for shock heating and/or UV continuumexcitation and ionization reproduce the extreme values of the [NII]:H/α ratios which we find here. We postulate that the extremely lowemissivity for [NII] which we see in these two objects may arise fromthe way in which the radio jet energized the interstellar gas in thegalaxy.
| Redshifts for a Sample of Radio-selected Poor Clusters
Multifiber optical spectroscopy has been performed on galaxies in thevicinity of strong, nearby radio galaxies. These radio galaxies wereselected from the 3CR and B2 catalogs based on their exclusion from theAbell catalog, which is puzzling given the hypothesis that an externalmedium is required to confine the radio plasma of such galaxies.Velocities derived from the spectra were used to confirm the existenceof groups and poor clusters in the fields of most of the radio galaxies.We find that all radio galaxies with classical Fanaroff-Riley type Imorphologies prove to reside in clusters, whereas the other radiogalaxies often appear to be recent galaxy-galaxy mergers in regions oflow galaxy density. These findings confirm the earlier result that theexistence of extended X-ray emission combined with a statistical excessof neighboring galaxies can be used to identify poor clusters associatedwith radio galaxies.
| Compact groups in the UZC galaxy sample
Applying an automatic neighbour search algorithm to the 3D UZC galaxycatalogue (Falco et al. \cite{Falco}) we have identified 291 compactgroups (CGs) with radial velocity between 1000 and 10 000 kms-1. The sample is analysed to investigate whether Tripletsdisplay kinematical and morphological characteristics similar to higherorder CGs (Multiplets). It is found that Triplets constitute lowvelocity dispersion structures, have a gas-rich galaxy population andare typically retrieved in sparse environments. Conversely Multipletsshow higher velocity dispersion, include few gas-rich members and aregenerally embedded structures. Evidence hence emerges indicating thatTriplets and Multiplets, though sharing a common scale, correspond todifferent galaxy systems. Triplets are typically field structures whilstMultiplets are mainly subclumps (either temporarily projected orcollapsing) within larger structures. Simulations show that selectioneffects can only partially account for differences, but significantcontamination of Triplets by field galaxy interlopers could eventuallyinduce the observed dependences on multiplicity. Tables 1 and 2 are onlyavailable in electronic at the CDS via anonymous ftp tocdsarc.u-strasbg.fr (130.79.125.5) or viahttp://cdsweb.u-strasbg.fr/cgi-bin/qcat?J/A+A/391/35
| A catalogue and analysis of X-ray luminosities of early-type galaxies
We present a catalogue of X-ray luminosities for 401 early-typegalaxies, of which 136 are based on newly analysed ROSAT PSPC pointedobservations. The remaining luminosities are taken from the literatureand converted to a common energy band, spectral model and distancescale. Using this sample we fit the LX:LB relationfor early-type galaxies and find a best-fit slope for the catalogue of~2.2. We demonstrate the influence of group-dominant galaxies on the fitand present evidence that the relation is not well modelled by a singlepower-law fit. We also derive estimates of the contribution to galaxyX-ray luminosities from discrete-sources and conclude that they provideLdscr/LB~=29.5ergs-1LBsolar-1. Wecompare this result with luminosities from our catalogue. Lastly, weexamine the influence of environment on galaxy X-ray luminosity and onthe form of the LX:LB relation. We conclude thatalthough environment undoubtedly affects the X-ray properties ofindividual galaxies, particularly those in the centres of groups andclusters, it does not change the nature of whole populations.
| The LX-σ Relation for Galaxies and Clusters of Galaxies
We demonstrate that individual elliptical galaxies and clusters ofgalaxies form a continuous X-ray luminosity-velocity dispersion(LX-σ) relation. Our samples of 280 clusters and 57galaxies have LX~σ4.4 andLX~σ10, respectively. This unifiedLX-σ relation spans 8 orders of magnitude inLX and is fully consistent with the observed and theoreticalluminosity-temperature scaling laws. Our results support the notion thatgalaxies and clusters of galaxies are the luminous tracers of similardark matter halos.
| The VSOP 5 GHz AGN Survey I. Compilation and Observations
The VSOP mission is a Japanese-led project to image radio sources withsub-milliarcsec resolution by correlating the signal from the orbiting8-m telescope, HALCA, with a global array of telescopes. Twenty-fivepercent of the scientific time of this mission is devoted to a survey of402 bright, small-diameter extra-galactic radio sources at 5 GHz. Themajor goals of the VSOP Survey are statistical in nature: to determinethe brightness temperature and approximate structure; to provide asource list for use with future space VLBI missions; and to compareradio properties with other data throughout the EM spectrum. This paperdescribes: the compilation of a complete list of radio sourcesassociated with active galactic nuclei (AGN); the selection of thesubsample of sources to be observed with VSOP; the extensive groundresources used for the Survey; the status of the observations as of 2000July; the data-analysis methods; and several examples of results fromthe VSOP Survey. More detailed results from the full sample will begiven in future papers.
| Radio, optical and X-ray nuclei in nearby 3CRR radio galaxies
HST observations have shown that low-redshift 3CR radio galaxies oftenexhibit a point-like optical component positionally coincident with theGHz-frequency radio core. In this paper we discuss the correlationbetween the luminosities of the radio, optical and X-ray cores in theseobjects, and argue that all three components have a common origin at thebase of the relativistic jets. In unified models, FR I radio galaxiesshould appear as dimmed, redshifted versions of BL Lac objects. We showthat such models are consistent with the spectral energy distributionsof the radio galaxies only if the nuclear X-ray emission in radiogalaxies is inverse Compton in origin.
| The VSOP 5 GHZ Continuum Survey: The Prelaunch VLBA Observations
We have imaged with milliarcsecond resolution at 5 GHz 374 strongflat-spectrum radio sources north of declination -44° using the VLBAin 1996 June. The source sample was compiled from the source list forthe VLBI Space Observatory Programme (VSOP) Survey Program. About 250 ofthe sources observed with the VLBA had correlated flux densities>=0.3 Jy on the longest VLBA baseline and these sources are currentlybeing observed with VSOP at 5 GHz. This paper presents the results fromthe VLBA prelaunch observations: the correlated flux density dependencewith u-v distance; the contour display of the images; the model fitparameters for each radio component; and improved positions for 62sources. Comparisons and extensive cross-referencing with other majorVLBI surveys are also given.
| An Imaging and Spectroscopic Survey of Galaxies within Prominent Nearby Voids. II. Morphologies, Star Formation, and Faint Companions
We analyze the optical properties of ~300 galaxies within and aroundthree prominent voids of the Center for Astrophysics Redshift Survey. Wedetermine CCD morphologies and Hα equivalent widths from ourimaging and spectroscopic survey. We also describe a redshift survey of250 neighboring galaxies in the imaging survey fields. We assess themorphology-density relation, EW(Hα)-density relation, and theeffects of nearby companions for galaxies in low-density environmentsselected with a smoothed large-scale (5 h-1 Mpc) galaxynumber density n. Both the morphological mix and the Hα line widthdistribution of galaxies at modest underdensities, 0.5R=16.13, demonstrates that the incidence ofa close companion in redshift space is insensitive to global densityover the range we investigate (0.163 σ) fromΔcz>~200 km s-1 at 0.5-1 at n<=0.5n. In the lowest densityenvironments, galaxies with companions clearly (~4 σ) havestronger star formation than comparable galaxies at larger globaldensity (0.5-1 kpc and 1000 km s-1) varies little over theentire density range. These results, combined with the luminosity- andcolor-density relations of this sample (Paper I), suggest that theformation and evolution of field galaxies are insensitive to large-scaleunderdensity down to a threshold of roughly half the mean density. Thedifferences in galaxy properties at the lowest global densities we canexplore (n<=0.5n) may be explained by (1) a relative scarcity of thesmall-scale primordial density enhancements needed to form massiveearly-type/absorption-line galaxies and (2) present-day galaxyencounters that are relatively more effective because of the lowervelocity dispersion on small scales (<~200 h-1 kpc) weobserve in these regions. In the voids, where the luminous galaxiespresumably formed more recently, there should be more gas and dustpresent for active star formation triggered by nearby companions.
| A Test for Large-Scale Systematic Errors in Maps of Galactic Reddening
Accurate maps of Galactic reddening are important for a number ofapplications, such as mapping the peculiar velocity field in the nearbyuniverse. Of particular concern are systematic errors which vary slowlyas a function of position on the sky, as these would induce spuriousbulk flow. We have compared the reddenings of Burstein & Heiles (BH)and those of Schlegel, Finkbeiner, & Davis (SFD) to independentestimates of the reddening, for Galactic latitudes |b|>10^deg. Ourprimary source of Galactic reddening estimates comes from comparing thedifference between the observed B-V colors of early-type galaxies, andthe predicted B-V color determined from the B-V-Mg_2 relation. We havefitted a dipole to the residuals in order to look for large-scalesystematic deviations. There is marginal evidence for a dipolar residualin the comparison between the SFD maps and the observed early-typegalaxy reddenings. If this is due to an error in the SFD maps, then itcan be corrected with a small (13%) multiplicative dipole term. Weargue, however, that this difference is more likely to be due to a small(0.01 mag) systematic error in the measured B-V colors of the early-typegalaxies. This interpretation is supported by a smaller, independentdata set (globular cluster and RR Lyrae stars), which yields a resultinconsistent with the early-type galaxy residual dipole. BH reddeningsare found to have no significant systematic residuals, apart from theknown problem in the region 230^deg
| Stellar population of ellipticals in different environments: near-infrared spectroscopic observations
Near-infrared spectra of 50 elliptical galaxies in the Pisces, Abell2199 and 2634 clusters, and in the general field, have been obtained.The strength of the CO (2.3-mu m) absorption feature in these galaxiesis used to explore the presence of an intermediate-age population (e.g.asymptotic giant branch stars) in ellipticals in different environments.We find that the strongest evidence for such a population comes fromellipticals in groups of a few members, which we interpret as the resultof recent minor merging of these galaxies with later-type galaxies.Field galaxies from very isolated environments, on the other hand, showno evidence for young or intermediate-age stars as revealed by Hβand CO absorptions, and appear to form a very uniform, old populationwith very little scatter in metallicity and star formation history.
| The peculiar motions of early-type galaxies in two distant regions - II. The spectroscopic data
We present the spectroscopic data for the galaxies studied in the EFARproject, which is designed to measure the properties and peculiarmotions of early-type galaxies in two distant regions. We have obtained1319 spectra of 714 early-type galaxies over 33 observing runs on 10different telescopes. We describe the observations and data reductionsused to measure redshifts, velocity dispersions and the Mgb and Mg_2Lick linestrength indices. Detailed simulations and intercomparison ofthe large number of repeat observations lead to reliable error estimatesfor all quantities. The measurements from different observing runs arecalibrated to a common zero-point or scale before being combined,yielding a total of 706 redshifts, 676 velocity dispersions, 676 Mgblinestrengths and 582 Mg_2 linestrengths. The median estimated errors inthe combined measurements are Delta cz=20 km s^-1, Delta sigma sigma=9.1 per cent, Delta Mgb Mgb=7.2 per cent and Delta Mg_2=0.015 mag.Comparison of our measurements with published data sets shows nosystematic errors in the redshifts or velocity dispersions, and onlysmall zero-point corrections to bring our linestrengths on to thestandard Lick system. We have assigned galaxies to physical clusters byexamining the line-of-sight velocity distributions based on EFAR andZCAT redshifts, together with the projected distributions on the sky. Wederive mean redshifts and velocity dispersions for these clusters, whichwill be used in estimating distances and peculiar velocities and to testfor trends in the galaxy population with cluster mass. The spectroscopicparameters presented here for 706 galaxies combine high-quality data,uniform reduction and measurement procedures, and detailed erroranalysis. They form the largest single set of velocity dispersions andlinestrengths for early-type galaxies published to date.
| X-ray luminosities for a magnitude-limited sample of early-type galaxies from the ROSAT All-Sky Survey
For a magnitude-limited optical sample (B_T <= 13.5 mag) ofearly-type galaxies, we have derived X-ray luminosities from the ROSATAll-Sky Survey. The results are 101 detections and 192 useful upperlimits in the range from 10^36 to 10^44 erg s^-1. For most of thegalaxies no X-ray data have been available until now. On the basis ofthis sample with its full sky coverage, we find no galaxy with anunusually low flux from discrete emitters. Below log (L_B) ~ 9.2L_⊗ the X-ray emission is compatible with being entirely due todiscrete sources. Above log (L_B) ~ 11.2 L_osolar no galaxy with onlydiscrete emission is found. We further confirm earlier findings that L_xis strongly correlated with L_B. Over the entire data range the slope isfound to be 2.23 (+/- 0.12). We also find a luminosity dependence ofthis correlation. Below log L_x = 40.5 erg s^-1 it is consistent with aslope of 1, as expected from discrete emission. Above this value theslope is close to 2, as expected from gaseous emission. Comparing thedistribution of X-ray luminosities with the models of Ciotti et al.leads to the conclusion that the vast majority of early-type galaxiesare in the wind or outflow phase. Some of the galaxies may have alreadyexperienced the transition to the inflow phase. They show X-rayluminosities in excess of the value predicted by cooling flow modelswith the largest plausible standard supernova rates. A possibleexplanation for these super X-ray-luminous galaxies is suggested by thesmooth transition in the L_x--L_B plane from galaxies to clusters ofgalaxies. Gas connected to the group environment might cause the X-rayoverluminosity.
| 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.
| Near-infrared Imaging of Early-Type Galaxies. II. Global Photometric Parameters
An imaging survey of 341 nearby early-type galaxies in the near-infraredK-band atmospheric window (2.2 μm) is described. The galaxiesprimarily reside in 13 nearby rich clusters (85%), while some additionalgalaxies are drawn from loose groups (12%) and the general field (3%).Surface photometry was measured for the entire sample. Detailedcorrections were derived from an extensive grid of seeing-convolvedr^1/4 models and then applied to the isophotal surface brightness,aperture magnitude, and ellipticity profiles. Global photometricparameters were derived from this seeing-corrected photometry. More than25% of the sample has been observed at least twice, and these repeatmeasurements demonstrate the small internal uncertainties on the derivedglobal photometric parameters. Extensive comparisons with aperturephotometry from the literature demonstrate that the photometric systemis fully consistent with other photometric systems to <=0.01 mag andconfirm the estimates of internal random uncertainties. Additionalglobal parameters are drawn from the literature in a homogeneous mannerin order to construct a large catalog of galaxy properties: 95% of thegalaxies have a velocity dispersion, 69% have a Mg_2 index, 80% have anoptical r_eff and μ_eff, 82% have a D_n, and 81% have a derivedoptical-infrared color measurement. This large data set providesexcellent source material for investigations of the physical origins ofthe global scaling relations of early-type galaxies, velocity fields inthe local universe, and comparisons to higher redshift early-typegalaxies.
| An X-Ray and Optical Investigation of the Environments around Nearby Radio Galaxies
Investigations of the cluster environment of radio sources have notshown a correlation between radio power and degree of clustering.However, it has been demonstrated that extended X-ray luminosity andgalaxy clustering do exhibit a positive correlation. This studyinvestigates a complete sample of 25 nearby (z<=0.06) radio galaxiesthat are not cataloged members of Abell clusters. The environment ofthese radio galaxies is studied in both the X-ray and the optical bymeans of the ROSAT All-Sky Survey (RASS), ROSAT pointed observations,and the Palomar optical Digitized Sky Survey (DSS). X-ray luminositiesand extents are determined from the RASS, and the DSS is used toquantify the degree of clustering via the spatial two-point correlationcoefficient, Bgg. Of the 25 sources, 20 are >=3 σdetections in the X-ray and 11 possessed Bgg's significantlyin excess of that expected for an isolated galaxy. Adding the criterionthat the X-ray emission be resolved, 10 of the radio galaxies do appearto reside in poor clusters with extended X-ray emission suggestive ofthe presence of an intracluster medium. Eight of these galaxies alsopossess high spatial correlation coefficients. Taken together, thesedata suggest that the radio galaxies reside in a low-richness extensionof the Abell clusters. The unresolved X-ray emission from the othergalaxies is most likely associated with active galactic nucleusphenomena. Furthermore, although the sample size is small, it appearsthat the environments of FR I and FR II sources differ. FR I's tend tobe more frequently associated with extended X-ray emission (10 of 18),whereas FR II's are typically point sources or nondetections in theX-ray (none of the seven sources exhibit extended X-ray emission).
| Progress in space VLBI science.
Not Available
| Radio jet interactions in the radio galaxy PKS 2152-699
We present radio observations of the radio galaxy PKS 2152-699 obtainedwith the Australia Telescope Compact Array. The much higher resolutionand signal-to-noise ratio of the new radio maps reveal the presence of abright radio component about 10 arcsec north-east of the nucleus. Thislies close to the highly ionized cloud previously studied in the opticaland here shown in a broad-band red snapshot image with the HST PC 2. Itsuggests that PKS 2152-699 may be a jet/cloud interaction similar to 3C277.3. This could cause the change in the position angle (of ~20 deg) ofthe radio emission from the inner to the outer regions. On the largescale, the source has Fanaroff & Riley type II morphology althoughthe presence of the two hotspots in the centres of the lobes is unusual.The northern lobe shows a particularly relaxed structure while thesouthern one has an edge-brightened, arc-like structure.
| A catalogue of Mg_2 indices of galaxies and globular clusters
We present a catalogue of published absorption-line Mg_2 indices ofgalaxies and globular clusters. The catalogue is maintained up-to-datein the HYPERCAT database. The measurements are listed together with thereferences to the articles where the data were published. A codeddescription of the observations is provided. The catalogue gathers 3541measurements for 1491 objects (galaxies or globular clusters) from 55datasets. Compiled raw data for 1060 galaxies are zero-point correctedand transformed to a homogeneous system. Tables 1, 3, and 4 areavailable in electronic form only at the CDS, Strasbourg, via anonymousftp 130.79.128.5. Table 2 is available both in text and electronic form.
| 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.
| H_2O megamaser emission from FR I radio galaxies
A systematic search for 22 GHz H_2O megamaser emission is reported for50 nearby (z la 0.15) FR I galaxies. No detection was obtained, implyingthat ultraluminous H_2O masers (L_H_2O > 10(3) Lsun) mustbe rare in early-type galaxies with FR I radio morphology. Despitehigher radio core luminosities the detection rate for our sample islower than in similar surveys of late-type Seyfert galaxies. Thispuzzling difference between Seyferts and low-power radio galaxies couldbe explained in several ways: a) the maser emission is saturated andtherefore independent of the radio core luminosity, b) the masers areunsaturated and originate in a thin circumnuclear gas disk, so the`seed' radio continuum would come from the far jet which isrelativistically dimmed or c) the amount, kinematics, or thedistribution of the molecular gas in the nuclei of Seyferts and radiogalaxies is different. Further studies of maser properties may provideclues to the differences between radio-loud and radio-quiet AGN.
| The peculiar motions of early-type galaxies in two distant regions. III - The photometric data
We present R-band CCD photometry for 776 galaxies observed in the EFARproject. The photometry is compared with photoelectric data, showingthat a common zero-point good to better than 1 per cent and a precisionof 0.03 mag per zero-point have been achieved. We give the circularlyaveraged surface brightness profiles and the photometric parameters ofthe 762 program galaxies, D(n) diameters, half-luminosity radii, totalmagnitudes, and average effective surface brightnesses. More than 80percent of the profiles have a global S/N ratio larger than 300. Theextrapolation needed to derive total magnitudes is less than 10 percentfor 80 percent of the fits. More than 80 percent of the galaxies havemean effective surface brightness larger than the observed skybrightness. In 90 percent of the profiles the estimate of thecontamination of the sky by the galaxy light is less than 1 percent. Wederive total magnitudes and half-luminosity radii to better than 0.15mag and 25 percent, respectively, for 90 percent of our sample. Incontrast, external comparisons show that data in the literature can bestrongly affected by systematic errors due to large extrapolations,small radial range, sky subtraction errors, seeing effects, and the useof a simple R exp 1/4 fit. The resulting errors can easily amount tomore than 0.5 mag in the total magnitudes and 50 percent in thehalf-luminosity radii.
| Galaxy clusters in the Perseus-Pisces region. I - Spectroscopic and photometric data for early-type galaxies
We present new spectroscopic and photometric data for 137 early-typegalaxies in nine clusters and for a set of nearby standard galaxies. Ourspectroscopic data comprise radial velocities, central velocitydispersions, and magnesium line strength indices. We demonstrate thatour new velocity dispersion data can be brought into consistency withthe standard system, to an uncertainty of percent 0.01 dex. From R-bandCCD photometry, we derive the effective diameter, the mean surfacebrightness within the effective diameter, and an R-band diameterequivalent to the Dn parameter of Dressler et al. Internal comparisonsindicate an average error of 0.005 in each measurement of log Dn. Thephotometric data can be brought on to a system consistent with externaldata at the level of 0.5 per cent in distance.
| [O III] 500.7 spectroscopy of 3C galaxies and quasars at redshift z>1
We present near infrared spectra of z>1 quasars and radio galaxiesfrom the 3CR and 3CRR catalogues. [O III] is detected in all but six ofthe 28 objects. These data extend the known correlation between the [OIII] and radio luminosities of radio sources to higher radioluminosities with no increase in scatter. The previously reporteddifference in [O III] luminosities between radio-luminous galaxies andquasars at z<0.8 is smaller at higher redshift and/or radioluminosity. In the context of orientation-based unified schemes of radiogalaxies and quasars, this implies that the [O III] emitting region ispartially hidden in the most radio-luminous galaxies seen at lowredshift (z~0.3) but less obscured in the even more radio-luminousgalaxies seen at z~1. Alternatively, such schemes do not apply to allobjects - perhaps there is a class of radio galaxies with highexcitation narrow emission lines but no luminous quasar nucleus.Equivalent widths of [O III] in the z>1 quasars are similar to thoseat lower z, implying no change in the excitation mechanism with z orradio luminosity.
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