Contents
Images
Upload your image
DSS Images Other Images
Related articles
Supernovae 2005kg, 2005kh, 2005ki, 2005kj, 2005kk
IAUC 8632 available at Central Bureau for Astronomical Telegrams.
| Discovery of Type IIn Supernova SNF20051117-001 and classification of Type Ia SN2005ki
The Nearby Supernova Factory reports the discovery of supernovaSNF20051117-001 (coordinates RA 08:40:09.18 DEC -05:36:02.2 J2000.0) inimages obtained November 17.5 UT with an approximate magnitude of 16.3(calibrated to R) using the QUEST II camera on the Palomar Oschin48-inch telescope as a part of the JPL Near-Earth Asteroid Trackingcomponent of the Palomar Consortium. A spectrum (range 320-1000 nm) ofthis object, obtained November 20.6 UT with the Supernova Integral FieldSpectrograph (SNIFS) on the University of Hawaii 2.2-meter telescope,shows it to be a Type IIn supernova at a redshift of z = 0.016,exhibiting H-alpha (FWHM 1300 km/s), H-beta, H- gamma and He I 587.6 inemission.
| Redshift-Distance Survey of Early-Type Galaxies: Spectroscopic Data
We present central velocity dispersions and Mg2 line indicesfor an all-sky sample of ~1178 elliptical and S0 galaxies, of which 984had no previous measures. This sample contains the largest set ofhomogeneous spectroscopic data for a uniform sample of ellipticalgalaxies in the nearby universe. These galaxies were observed as part ofthe ENEAR project, designed to study the peculiar motions and internalproperties of the local early-type galaxies. Using 523 repeatedobservations of 317 galaxies obtained during different runs, the dataare brought to a common zero point. These multiple observations, takenduring the many runs and different instrumental setups employed for thisproject, are used to derive statistical corrections to the data and arefound to be relatively small, typically <~5% of the velocitydispersion and 0.01 mag in the Mg2 line strength. Typicalerrors are about 8% in velocity dispersion and 0.01 mag inMg2, in good agreement with values published elsewhere.
| Redshift-Distance Survey of Early-Type Galaxies: Circular-Aperture Photometry
We present R-band CCD photometry for 1332 early-type galaxies, observedas part of the ENEAR survey of peculiar motions using early-typegalaxies in the nearby universe. Circular apertures are used to tracethe surface brightness profiles, which are then fitted by atwo-component bulge-disk model. From the fits, we obtain the structuralparameters required to estimate galaxy distances using theDn-σ and fundamental plane relations. We find thatabout 12% of the galaxies are well represented by a pure r1/4law, while 87% are best fitted by a two-component model. There are 356repeated observations of 257 galaxies obtained during different runsthat are used to derive statistical corrections and bring the data to acommon system. We also use these repeated observations to estimate ourinternal errors. The accuracy of our measurements are tested by thecomparison of 354 galaxies in common with other authors. Typical errorsin our measurements are 0.011 dex for logDn, 0.064 dex forlogre, 0.086 mag arcsec-2 for<μe>, and 0.09 for mRC,comparable to those estimated by other authors. The photometric datareported here represent one of the largest high-quality and uniformall-sky samples currently available for early-type galaxies in thenearby universe, especially suitable for peculiar motion studies.Based on observations at Cerro Tololo Inter-American Observatory (CTIO),National Optical Astronomy Observatory, which is operated by theAssociation of Universities for Research in Astronomy, Inc., undercooperative agreement with the National Science Foundation (NSF);European Southern Observatory (ESO); Fred Lawrence Whipple Observatory(FLWO); and the MDM Observatory on Kitt Peak.
| 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
| The Optical and Near-Infrared Morphologies of Isolated Early-Type Galaxies
To study early-type galaxies in their simplest environments, we haveconstructed a well-defined sample of 30 isolated galaxies. The samplecontains all early-type galaxies listed in the Third Reference Catalogueof Bright Galaxies (RC3) with no other cataloged galaxy with a knownredshift lying within a projected radius of 1h-1100 Mpc and +/-1000 km s-1 (where weuse the recession velocities in the RC3). We have obtained optical andnear-infrared images of 23 of the galaxies and of a comparison sample of13 early-type galaxies in X-ray-detected poor groups of galaxies. Wehave applied the techniques of unsharp-masking, galaxy model division,and color maps to search for morphological features that might provideclues to the evolution of these galaxies. Evidence for dust features isfound in approximately 75% of both the isolated and group galaxies (17of 22 and 9 of 12, respectively). However, shells or tidal features aremuch more prevalent in our isolated sample than in our group sample (9of 22=41% vs. 1 of 12=8%, respectively). The isolation and colors ofthese shell galaxies make it unlikely that tidal interactions orasymmetric star formation are the causes of such features. One modelthat is not ruled out is that mergers produce the shells. If shells anddust are both merger signatures, the absence of shells in groupelliptical galaxies implies that shells (1) form more easily, (2) areyounger, and/or (3) are longer lived in isolated environments.
| 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.
| An image database. II. Catalogue between δ=-30deg and δ=70deg.
A preliminary list of 68.040 galaxies was built from extraction of35.841 digitized images of the Palomar Sky Survey (Paper I). For eachgalaxy, the basic parameters are obtained: coordinates, diameter, axisratio, total magnitude, position angle. On this preliminary list, weapply severe selection rules to get a catalog of 28.000 galaxies, wellidentified and well documented. For each parameter, a comparison is madewith standard measurements. The accuracy of the raw photometricparameters is quite good despite of the simplicity of the method.Without any local correction, the standard error on the total magnitudeis about 0.5 magnitude up to a total magnitude of B_T_=17. Significantsecondary effects are detected concerning the magnitudes: distance toplate center effect and air-mass effect.
| UGC galaxies stronger than 25 mJy at 4.85 GHz
UGC galaxies in the declination band +5 to +75 deg were identified byposition coincidence with radio sources stronger than 25 mJy on theGreen Bank 4.85 GHz sky maps. Candidate identifications were confirmedor rejected with the aid of published aperture-synthesis maps and new4.86 GHz VLA maps having 15 or 18 arcsec resolution, resulting in asample of 347 nearby radio galaxies plus five new quasar-galaxy pairs.The radio energy sources in UGC galaxies were classified as 'starbursts'or 'monsters' on the basis of their infrared-radio flux ratios, infraredspectral indices, and radio morphologies. The rms scatter in thelogarithmic infrared-radio ratio q is not more than 0.16 for starburstgalaxies selected at 4.85 GHz. Radio spectral indices were obtained fornearly all of the UGC galaxies, and S0 galaxies account for adisproportionate share of the compact flat-spectrum (alpha less than0.5) radio sources. The extended radio jets and lobes produced bymonsters are preferentially, but not exclusively, aligned within about30 deg of the optical minor axes of their host galaxies. The tendencytoward minor-axis ejection appears to be independent of radio-sourcesize and is strongest for elliptical galaxies.
| On the relationship between radio emission and optical properties in early-type galaxies
To study the origin of radio activity in early-type galaxies, thepossible dependence of their radio emission on basic optical parameters,such as the absolute magnitude, the central velocity dispersion sigma,and the mean surface brightness mu is explored. A sample of 743 E and SOgalaxies is used which is based on three independent radio surveys ofoptically selected galaxies with virtually complete information onmagnitudes, morphological types, redshift distances, diameters, andradio fluxes. For both E and SO galaxies, only the absolute magnitudeappears to be directly related to the radio activity, while sigma and mudo not. Also, a significant dependence of the apparent flattening onradio power is confirmed for E galaxies. Some relevant implications ofthese results are discussed.
| A survey of galaxy redshifts. IV - The data
The complete list of the best available radial velocities for the 2401galaxies in the merged Zwicky-Nilson catalog brighter than 14.5mz and with b (II) above +40 deg or below -30 deg ispresented. Almost 60 percent of the redshifts are from the CfA surveyand are accurate to typically 35 km/s.
| Radio observations of early-type galaxies
A complete sample of 34 nearby early-type galaxies, based on the Arecibosurvey by Dressel and Condon (1978) of objects from the Uppsala GeneralCatalogue, has now been mapped at radio frequencies. New data arepresented for 23 galaxies in the sample, and references are given topublished maps of the remainder. The majority of the sources show strongjet-like structures, but others remain unresolved. These latter occurprimarily in galaxies classed as S0 in the UGC. A strong correlationbetween radio luminosity and size has been found with log P (2.7 GHz)between 23.0 and 25.0. This correlation is in the sense that weaksources are confined within the optical extent of their parent galaxies,whereas strong sources generally attain large sizes. A tentativeexplanation of this tendency is offered in terms of the flowinstabilities in beams of energetic particles passing through densemedia.
| Redshifts of 31 bright galaxies
Optical spectroscopy of 31 bright galaxies, most of which are among theUGC galaxies detected at 2380 MHz by Dressel and Condon (1978), isreported. The observations were made at the McDonald Observatory withthe 2.7-m NASA reflector (except for UGC 3915, 4752, 5507, and 9357, forwhich the 2.1-m Struve reflector was used).
| VLBI observations of galactic nuclei
A three telescope VLBI survey has been carried out of optically brightgalaxies with nuclear radio sources which are unresolved at a fewseconds of arc. Twenty out of 58 galaxies were detected at 18 cm,indicating the presence of radio structure on a scale of about 10milli-arcsec. Most of these were normal galaxies, although emissionlines were present in many cases. Fifteen of the galaxies detected inthe survey (as well as M51, M81, and M82) were then observed in a sixtelescope VLBI network experiment to determine the general structure ofthe compact nuclear sources. Models of the milli-arcsec radio structurewere developed for 17 of these 18 galaxies. Except for the unusuallycomplex source in M87, the models are all composed of a small number ofcomponents in a region no larger than a few parsecs. They resemblemodels and hybrid maps of the compact sources in quasars and activegalaxies, indicating that a common physical mechanism is probablyresponsible for the compact radio sources in a wide range of opticalobjects.
| The H I content of isolated galaxies
H I data are presented for 33 galaxies from Huchra and Thuan's list(1977) among which eleven are isolated. Analysis of the data shows that(1) the H I content of isolated galaxies is about 60% higher than thatof group galaxies; (2) at least 6 out of the 9 isolated galaxiesexamined appear to be associated with groups of galaxies of the sameredshift, at distances of about 4 Mpc on an average; and (3) the excessof H I in isolated galaxies is related to their large distances to thecenters of the groups.
| Very-long-baseline interferometry of compact sources in bright galaxies
Thirty-one optically bright galaxies with compact radio nuclei have beenobserved with a 20-million-wavelength baseline at 2380 MHz. Thirteennuclei have been detected, with angular sizes smaller than 0.01 arcsec.Twelve of the detected nuclei have flat spectra and are about 1 pc, orsmaller, in size. This confirms the continuity of properties from theradio nuclei of strong radio galaxies to the less-luminous nuclei ofnearby bright galaxies.
| Compact radio sources in and near bright galaxies
Compact radio sources in galaxies stronger than 35 mJy at 2380 MHz fromthe Arecibo survey of galaxies brighter than a photographic magnitude of+14.5 have been detected and observed at 2695 and 8085 MHz with the NRAOthree-element interferometer. Accurate radio and optical positions showthat all compact radio sources identifiable with these galaxies arelocated in their nuclei. Five new BSO (blue stellar object)/galaxy pairswere discovered, and the BSO 0241 +011 lies in a spiral arm of thegalaxy U02210 = N1073. The number of BSO/galaxy pairs is compatible withrandom projection of cosmological QSOs onto bright galaxy fields. Mostof the nuclear compact sources, and nearly all of those with flatspectra, are found in E or S0 galaxies. Early Hubble subtypes arefavored in spiral galaxies with compact radio sources, and there is astrong tendency for them to occur in paired galaxies. These observationsare interpreted in terms of accretion by massive black holes in galacticnuclei.
|
Submit a new article
Related links
Submit a new link
Member of following groups:
|
Observation and Astrometry data
Catalogs and designations:
|
