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Classifications of the Host Galaxies of Supernovae
Classifications on the DDO system are given for the host galaxies of 177supernovae (SNe) that have been discovered since 1997 during the courseof the Lick Observatory Supernova Search with the Katzman AutomaticImaging Telescope. Whereas SNe Ia occur in all galaxy types, it isfound, at a high level of statistical confidence, that SNe Ib, Ic, andII are strongly concentrated in late-type galaxies. However, attentionis drawn to a possible exception provided by SN 2001I. This SN IInoccurred in the E2 galaxy UGC 2836, which was not expected to harbor amassive young supernova progenitor.
| Supernova 2001ic in NGC 7503
IAUC 7783 available at Central Bureau for Astronomical Telegrams.
| Supernova 2001ic in NGC 7503
IAUC 7783 available at Central Bureau for Astronomical Telegrams.
| Jet-triggered Type Ia Supernovae in Radio Galaxies?
We report the serendipitous discovery of a supernova (SN) in the nearbyradio galaxy 3C 78. Observations obtained with the Space TelescopeImaging Spectrograph on board the Hubble Space Telescope show, at adistance of 0.54" (300 pc) from the galaxy nucleus, a second brightsource, not present in previous images. As this source was fortuitouslycovered by the spectrograph slit, its spectrum was obtained, and it ischaracteristic of a Type Ia SN. This SN is closely aligned with theradio jet of 3C 78. Analysis of historical records shows that such aclose association between jet and SN occurred in six of the 14 reportedSNe in radio galaxies. The probability that this results from a randomdistribution of SNe in the host galaxy is less than ~0.05%. We thenargue that jets might trigger SN explosions. Based on observations withthe NASA/ESA Hubble Space Telescope, obtained at the Space TelescopeScience Institute, which is operated by the Association of Universitiesfor Research in Astronomy, Inc., under NASA contract NAS5-26555 andSTScI grant GO-3594.01-91A.
| A new list of extra-galactic radio jets
A catalogue of extra-galactic jets is very useful both in observationaland theoretical studies of active galaxies. With the use of new powerfulradio instruments, the detailed structures of very compact or weak radiosources are investigated observationally and many new radio jets aredetected. In this paper, we give a list of 661 radio sources withdetected radio jets known to us prior to the end of December 2000. Allreferences are collected for the observations of jets in radio, IR,optical, UV and X-ray wave-bands. Table 1 and references to Table 1 areonly 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/381/757
| Supernova 2001ic in NGC 7503
IAUC 7770 available at Central Bureau for Astronomical Telegrams.
| Mass and Metallicity of Five X-Ray-bright Galaxy Groups
We present ASCA X-ray observations of a sample of five groups selectedfrom a cross-correlation of the ROSAT All-Sky Survey with the White etal. optical catalog of groups. These X-ray-bright groups significantlyincrease the number of known systems with temperatures between 2 and 3keV. They have element abundances of roughly 0.3solar, which are typicalof clusters, but their favored ratio of Si-to-Fe abundance is lower thanthe cluster value. Combining the ASCA results with ROSAT imaging data,we calculate total masses of a few to several times 10^13 M_solar, gasmass fractions of ~10%, and baryonic mass fractions of at least 15%-20%within a radius of 0.5 Mpc. Upper limits for the ratios of gas to galaxymass and of the iron mass to galaxy luminosity overlap with the rangeobserved in rich clusters and extend to lower values, but not to suchlow values as seen in much poorer groups. These results support the ideathat groups, unlike clusters, are subject to the loss of theirprimordial and processed gas and show that this transition occurs at themass scale of the 2-3 keV groups. A discussion of ASCA calibrationissues and a comparison of ROSAT and ASCA temperatures are included inan Appendix.
| Linear polarization measurements of extragalactic radio sources at lambda 6.3 CM
We present linear polarization measurements of 154 extragalactic radiosources at lambda6 .3 cm, as part of a continuing effort to expand andimprove our Faraday rotation determinations of radio galaxies andquasars. The excellent telescope optics of the Effelsberg 100 mtelescope at this wavelength, combined with a matrix method we appliedfor calibrating out all components of the instrumental polarizationenables us to achieve better than average accuracy in the determinationsof linear polarization degree and position angle. In the absence ofthermal noise errors, these are repeatable to better than 0.2% and 0fdg1 respectively, for the prime calibrator, 3C 286. A very brief overviewof the results is also included.
| 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.
| Photoelectric UBV Photometry of Galaxies in the Clusters Pegasus I, Pegasus II, Abell 262, Abell 1367, and Abell 2197-9
This paper presents photoelectric UBV multiaperture photometry of 144galaxies, 139 of which are associated with six nearby bright clusters.The observations were made at the McDonald Observatory from 1986September to 1987 November and were part of the production of the ThirdReference Catalogue of Bright Galaxies (RC3). The observations were usedto compute total magnitudes and color indices published in RC3. Theobservations can also be used to calibrate CCD images.
| The fundamental plane of early-type galaxies: stellar populations and mass-to-light ratio.
We analyse the residuals to the fundamental plane (FP) of ellipticalgalaxies as a function of stellar-population indicators; these are basedon the line-strength parameter Mg_2_ and on UBVRI broad-band colors, andare partly derived from new observations. The effect of the stellarpopulations accounts for approximately half the observed variation ofthe mass-to-light ratio responsible for the FP tilt. The residual tiltcan be explained by the contribution of two additional effects: thedependence of the rotational support, and possibly that of the spatialstructure, on the luminosity. We conclude to a constancy of thedynamical-to-stellar mass ratio. This probably extends to globularclusters as well, but the dominant factor would be here the luminositydependence of the structure rather than that of the stellar population.This result also implies a constancy of the fraction of dark matter overall the scalelength covered by stellar systems. Our compilation ofinternal stellar kinematics of galaxies is appended.
| A Catalog of Stellar Velocity Dispersions. II. 1994 Update
A catalog of central velocity dispersion measurements is presented,current through 1993 September. The catalog includes 2474 measurementsof 1563 galaxies. A standard set of 86 galaxies is defined, consistingof galaxies with at least three reliable, concordant measurements. It issuggested that future studies observe some of these standard galaxies sothat different studies can be normalized to a consistent system. Allmeasurements are reduced to a normalized system using these standards.
| ROSAT Observations of Five Poor Galaxy Clusters with Extended Radio Sources
We present the results of deep ROSAT PSPC observations of the poorclusters MKW2, N79-299A, S49-128, S49-132, and S49-140. These poorclusters all contain extended radio sources, generally with a bent,head- tail (HT) morphology. It had been previously thought that HTsshould only be found in rich clusters, which have sufficiently highintracluster medium (ICM) densities and velocity dispersions foreffective ram pressure bending of the radio jets. We have found that theX-ray emission associated with these poor clusters is generally quiteclumpy and asymmetrical. Often, the clumps are associated with subgroupsor individual galaxies, as well as with extended regions around theradio sources. Our results also indicate that there is a continuum ofX-ray properties from poor to rich clusters. In many respects, poorclusters seem to be a low-mass extension of rich clusters. We find thatthese poor clusters have baryon fractions ranging from 1% to 25%. Also,the radio sources within these clusters are probably thermally confinedby the ICM. Although four of our clusters have central X-ray luminosityexcesses, the implied cooling times are longer than a Hubble time. Weinterpret the central X-ray luminosity excesses as unresolved galaxyemission. We hypothesize that these poor clusters have recentlycollapsed out of large, loose clouds of galaxies. We believe that manyof the poor cluster properties are understandable in light of thishypothesis. First, four of these five clusters are embedded withinlarger Zwicky clusters. This may indicate that these large Zwickyclusters act as "incubators" of poor clusters. Second, the observedflat, broad velocity distributions may reflect the velocities associatedwith the larger-scale systems from which we believe that these poorclusters have collapsed. Third, some of these galaxies (such as NGC4061, within N79-299A) show signs of interactions with neighboringgalaxies with large relative velocities (~850 km/s). Fourth, theobserved ICM densities, coupled with velocity distributions which aresuggestive of unrelaxed systems, and the peculiar velocities of theradio galaxies may explain the ram pressure bending of the radio jets inthe HTs.
| Integrated photoelectric magnitudes and color indices of bright galaxies in the Johnson UBV system
The photoelectric total magnitudes and color indices published in theThird Reference Catalogue of Bright Galaxies (RC3) are based on ananalysis of approximately equals 26,000 B, 25,000 B-V, and 17,000 U-Bmultiaperture measurements available up to mid 1987 from nearly 350sources. This paper provides the full details of the analysis andestimates of internal and external errors in the parameters. Thederivation of the parameters is based on techniques described by theVaucouleurs & Corwin (1977) whereby photoelectric multiaperture dataare fitted by mean Hubble-type-dependent curves which describe theintegral of the B-band flux and the typical B-V and U-B integrated colorgradients. A sophisticated analysis of the residuals of thesemeasurements from the curves was made to allow for the random andsystematic errors that effect such data. The result is a homogeneous setof total magnitudes BTA total colors(B-V)T and (U-B)T, and effective colors(B-V)e and (U-B)e for more than 3000 brightgalaxies in RC3.
| Why do head-tail sources exist in poor clusters of galaxies?
In a continuing study of nearby (z approximately 0.02-0.05) radiosources in poor clusters of galaxies, we obtained Very Large Array (VLA)observations of four head-tail (HT) sources as probes of theintracluster environments: NGC 742, NGC 1044, NGC 4061, and NGC 7503.NGC 742 apparently has a companion, NGC 741, in the midst of itsextended tail structure. NGC 7503 and NGC 4061 have horseshoe shapesvery similar to the archetypal HT radio galaxy, NGC 1265. Thesestructures are remarkable because the sources are found in poor groups,where both the average density of the intracluster medium (ICM) and thevelocities of the galaxies (thus the ram pressures) are supposedly muchlower than in the rich clusters. Yet these poor groups have narrow-angletail (NAT) sources with the same general morphologies as those in richclusters. There is not much difference between our poor-cluster NATsources and rich-cluster NAT sources, in terms of jet radii ofcurvature, jet opening angles, internal ram pressures within the jets,jet luminosity as a fraction of total source luminosity, and ICMdensities. It appears that the HT phenomenon is remarkably similarbetween the poor clusters and the rich clusters because the localconditions near these sources within their clusters are similar. An ICMdensity typical of that found in poor clusters (approximately10-4/cc and a galaxy velocity typical of the rich clusters(approximately 600 km/s) provide sufficient ICM ram pressure to bendradio jets into NAT morphologies. One explanation for the high relativevelocities of the poor cluster HT galaxies is that these clusters aredynamically young and are still collapsing.
| Head tail sources in poor clusters of galaxies
Head tail sources in poor clusters of galaxies have been studied usingthe VLA at wavelengths of 6 cm and 20 cm. Four sources (NGC 742, NGC1044, NGC 4061 and NGC 7503) were selected from a larger sample fordetailed study. These sources represent an exceptional opportunity tostudy radio jets and their interaction with the cluster environment, indetail, because of their proximity (z ~ 0.02 to 0.04). NGC 4061 and NGC7503 exhibit narrow-angle-tail (NAT) morphologies similar to the classicrich cluster NAT, NGC 1265. NGC 742 has a complex morphology while NGC1044 shows a wide-angle-tail (WAT) morphology. The NAT morphologies arebelieved to be the result of the intracluster medium (ICM) rampressures. The poor cluster NATs are thus remarkable because the poorcluster ICM ram pressure is expected to be much lower, in general, thanin rich clusters. Comparisons of the results of the poor cluster sourceswith those of NGC 1265 should reveal much about the radio source andcluster environment interaction. Most of the parameters calculated suchas jet luminosity as a fraction of total source luminosity, jet openingangle, jet radius of curvature and the ICM density surrounding thesources are quite similar between NGC 1265 and the poor cluster sources.This is a very surprising result and we conclude that ICM densitiestypical of poor clusters and a galaxy relative velocity ~ 1000 km s(-1)provide sufficient ram pressure to bend radio jets into NATmorphologies. Spectral indices and polarization structures have beencompared between the rich and poor clusters and are found to be similaras well. The spectral indices in the poor cluster sources (alpha_ {jet}~ -0.6 and alpha_ {tail} \approx -0.8) are similar to those of the richcluster sources. The fractional polarizations vary from \sim 10% in thejets to \sim 30%$ in the tails similar to the rich cluster HT sources.The magnetic field structure appears to follow the general structureseen in low luminosity radio sources. The overall result is theremarkable similarity between the HT phenomenon in the rich and poorclusters.
| Why Do Head Tail Sources Exist In Poor Clusters Of Galaxies?
In a continuing study of radio sources in poor clusters of galaxies, wehave obtained VLA observations of four head-tail sources as probes ofthe intracluster environments: NGC 742, NGC 1044, NGC 4061, and NGC7503. These sources represent an exceptional opportunity for the studyof radio sources (and radio jets in particular). They are very nearby (z~ 0.02 to 0.04) and thus can be examined in great detail, much like NGC1265 in Perseus. The four sources contain some remarkable structures.NGC 742 apparently has a companion, NGC 741, in the midst of itsextended tail structure. NGC 7503 has a horseshoe shape very similar toNGC 1265. The NGC 4061 source maintains a very linear structure out toequal distances on either side of the galaxy center, where the lobes aresharply `swept back.' These structures are remarkable because thesources are found in poor groups, where both the density of the ICM andthe velocities of the galaxies (thus the ram pressures) are supposedlymuch lower than in the rich clusters. Yet these poor groups havenarrow-angle-tail sources (NATs) with the same general characteristicsas those in rich clusters. Our calculations indicate that there is notmuch difference between the poor cluster sources and NGC 1265 in ICMdensities, jet luminosity as a fraction of total source luminosity, andradii of curvature of the jets. These are very surprising results. Whilethe jets of two sources (NGC 4061 and NGC 7503) appear to have roughlytwice the opening angle of the NGC 1265 jet (which suggests lesserpressure-confinement in poor clusters), most of our evidence pointstoward remarkably similar environments for rich and poor cluster jets.
| Numerical models of extragalactic radio sources
When supercomputer-implemented numerical simulations analyzing thenonlinear physics inherent in the hydrodynamic and MHD equations areapplied to extragalactic radio sources, many of the complex structuresobserved on telescopic images are reproduced. Attention is presentlygiven to recently obtained results from 2D and 3D numerical simulationsof the formation and evolution of extended radio morphologies; thesenumerical models allow the exploration of such physical phenomena as therole of magnetic fields in the dynamics and emissivity of extended radiogalaxies, intermittent outflow from the cores of active galaxies,fluid-jet instabilities, and the bending of collimated outflows bymotion through the intergalactic medium.
| Head-tail radio sources in poor clusters of galaxies : VLA Observations and comparisons to rich cluster HTs.
Not Available
| Infrared properties of nearby radio galaxies
The IRAS data for a sample of nearby radio galaxies (z less than 0.13)are analyzed. Comparison of the infrared, radio, and optical datasuggests that most of the long-wavelength infrared emission comes fromcool interstellar dust for almost all of the galaxies; these galaxiesmay contain large amounts (10 to the 8th - 10 to the 10th solar massesof interstelar matter. About 15 percent of the galaxies show evidencefor a hotter thermal component emitting at the shorter IRAS wavelengths;this could be due to dust in the inner regions of the galaxy heated bythe active galactic nucleus.
| The cluster environments of powerful radio galaxies
Results in the form of the ratio of the spatial cross-correlationamplitude to the autocorrelation amplitude are given as estimates of thelocal galaxy density around about 200 powerful radio sources. Lickgalaxy counts for z of less than 0.1 are extended to z of less than 0.25using deep galaxy samples from UK Schmidt plates. Although thelow-luminosity Fanaroff-Riley class I sources lie in richer clustersthan those of class II, a real scatter in properties is found. Theresults show no statistical evidence for the difference in environmentsuggested to exist between different subclasses of the class II sources.Compact radio sources are found to lie in regions of low galacticdensity.
| Determination of the relative spectrophotometric gradients of galaxies. IV
Relative spectrophotometric gradients of continua are determined for 195galaxies. The spectra have been obtained with the 70-cm meniscustelescope of the Abastumani Astrophysical Observatory using a 2-degpreobjective prism (the reverse linear dispersion was 1200 A/mm inH-gamma). The gradient values were reduced to the AO spectral class andcorrected for light absorption in the Galaxy.
| IRAS observations of radio galaxies
IRAS measurements at 25, 60, and 100 microns have been used to analyzethe far-infrared properties of radio galaxies. Fifty-eight of the 131objects surveyed were detected at the level of better than 300 mJy at 60microns. The most powerful radio galaxies are strong emitters in the farinfrared. Large infrared emission is shown to be correlated with thepresence of strong emission lines in the optical spectra. The infraredcolors of the strong radio galaxies are similar to those of MarkarianSeyferts. The results are shown to be consistent with recent resultsimplying that the host galaxies of radio sources are not normal giantellipticals and that galaxy-galaxy interactions may power luminous radiosources. Finally, some similarities between powerful radio galaxies andpowerful infrared galaxies are noted and briefly discussed.
| A VLA 20 CM survey of poor groups of galaxies
The paper reports on VLA 20 cm observations of an extensive sample ofgalaxies in 139 poor groups. These groups, composed of galaxies down tothe limit of the Zwicky et al. (CGCG) catalog, were chosen using apercolation algorithm set at a high surface-density threshold.Approximately 50 percent of the groups have measured redshifts. Thesegroups were surveyed using a 'snapshot' mode of the VLA with aresolution of about 13 arcsec. Analysis of the resulting radio andoptical properties reveals that the presence of a nearby companiongalaxy has an important role in generating radio emission in a galaxy.CCD observations of two radio-loud, disturbed galaxies with companionsare presented and are used to discuss models of radio-source production.Nine tailed radio galaxies are found in the poor groups, which is muchmore than had been expected from previous work on rich clusters and fromtheoretical models. The paper discusses previous statistical biases andproposes a method for bending head-tail sources in poor groups. From theconfinement of extended radio features associated with tailed sources,the presence of a substantial intracluster medium that should radiatesignificantly at soft-X-ray energies is predicted.
| Individual and orbital masses of double galaxies
A list is given of individual estimates of the masses of 124 componentsof isolated pairs of galaxies from Turner's catalog for which there arepublished data on the velocity dispersions in the central parts of thegalaxies, on the width of the 21-cm radio line profile, and on theamplitude of the rotation curve of the galaxies. From the comparison ofthe orbital estimates of the mass with the sum of the individual massesof the double galaxies it is concluded that the bulk of the mass of thegalaxies is situated within their standard optical diameter A(25). Theconsidered observational data for the Turner galaxy pairs do not containany arguments for the hypothesis of massive halos. Good agreementbetween the orbital and individual estimates of the mass is observed foralmost circular motions of the galaxies in pairs with mean orbitaleccentricity 0.25.
| A catalog of stellar velocity dispersions. I - Compilation and standard galaxies
A catalog of central stellar velocity dispersion measurements ispresented, current through June 1984. The catalog includes 1096measurements of 725 galaxies. A set of 51 standard galaxies is definedwhich consists of galaxies with at least three reliable, concordantmeasurements. It is suggested that future studies observed some of thesestandard galaxies in the course of their observations so that differentstudies can be normalized to the same system. Previous studies arecompared with the derived standards to determine relative accuracies andto compute scale factors where necessary.
| A survey of O II forbidden line emission in elliptical galaxies
A survey of elliptical galaxy spectra using image-tube spectrograms hasbeen carried out with the result that 40 percent of the galaxies havebeen found to contain ionized gas. Galaxies with intense nuclearemission also tend to have extended emission that appears to be confinedto a plane. Since there is a detectable velocity gradient for the gas inthose planes, the gas appears to be in a rotating disk.
| A comparison of distance scales for early-type galaxies
The distance scales of elliptical and lenticular galaxies areintercompared, based on the velocity dispersion indicator derived from arevised Faber-Jackson relation. The scales are found to be in nearperfect agreement with scales derived from the luminosity index and fromthe 21 cm line width indicator. The scales are also in excellentagreement with the distance scale derived by Michard (1979). Additionsare offered for the general catalog of 424 early-type galaxies, and aseries of reduction equations is presented which reduces the externalerrors in the distance moduli.
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