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Публикации по объекту
Late-Time Radio Observations of 68 Type Ibc Supernovae: Strong Constraints on Off-Axis Gamma-Ray Bursts
We present late-time radio observations of 68 local Type Ibc supernovae,including six events with broad optical absorption lines(``hypernovae''). None of these objects exhibit radio emissionattributable to off-axis gamma-ray burst jets spreading into our line ofsight. Comparison with our afterglow models reveals the followingconclusions. (1) Less than ~10% of Type Ibc supernovae are associatedwith typical gamma-ray bursts initially directed away from our line ofsight; this places an empirical constraint on the GRB beaming factor of<~104, corresponding toan average jet opening angle, θj>~0.8d. (2) Thisholds in particular for the broad-lined supernovae (SNe 1997dq, 1997ef,1998ey, 2002ap, 2002bl, and 2003jd), which have been argued to host GRBjets. Our observations reveal no evidence for typical (or evensubenergetic) GRBs and rule out the scenario in which every broad-linedSN harbors a GRB at the 84% confidence level. Their large photosphericvelocities and asymmetric ejecta (inferred from spectropolarimetry andnebular spectroscopy) appear to be characteristic of the nonrelativisticSN explosion and do not necessarily imply the existence of associatedGRB jets.
| The structure of galactic disks. Studying late-type spiral galaxies using SDSS
Using imaging data from the SDSS survey, we present the g' and r' radialstellar light distribution of a complete sample of ~90 face-on tointermediate inclined, nearby, late-type (Sb-Sdm) spiral galaxies. Thesurface brightness profiles are reliable (1 σ uncertainty lessthan 0.2 mag) down to μ27 mag/''. Only ~10% of all galaxies havea normal/standard purely exponential disk down to our noise limit. Thesurface brightness distribution of the rest of the galaxies is betterdescribed as a broken exponential. About 60% of the galaxies have abreak in the exponential profile between 1.5-4.5 times thescalelength followed by a downbending, steeper outer region. Another~30% shows also a clear break between 4.0-6.0 times thescalelength but followed by an upbending, shallower outer region. A fewgalaxies have even a more complex surface brightness distribution. Theshape of the profiles correlates with Hubble type. Downbending breaksare more frequent in later Hubble types while the fraction of upbendingbreaks rises towards earlier types. No clear relation is found betweenthe environment, as characterised by the number of neighbours, and theshape of the profiles of the galaxies.
| Classifications of the Host Galaxies of Supernovae, Set II
Classifications on the DDO system are given for an additional 231 hostgalaxies of supernovae that have been discovered during the course ofthe Lick Observatory Supernova Search with the Katzman Automatic ImagingTelescope (KAIT). This brings the total number of hosts of supernovae(SNe) discovered (or independently rediscovered) by KAIT, which have sofar been classified on a homogeneous system, to 408. The probabilitythat SNe Ia and SNe II have a different distribution of host-galaxyHubble types is found to be 99.7%. A significant difference is alsofound between the distributions of the host galaxies of SNe Ia and ofSNe Ibc (defined here to include SNe Ib, Ib/c, and Ic). However, nosignificant difference is detected between the frequency distributionsof the host galaxies of SNe II and SNe IIn. This suggests that SNe IInare generally not SNe Ia embedded in circumstellar material that aremasquerading as SNe II. Furthermore, no significant difference is foundbetween the distribution of the Hubble types of the hosts of SNe Ibc andof SNe II. Additionally, SNe II-P and SNe II-L are found to occur amongsimilar stellar populations. The ratio of the number of SNe Ia-pec tonormal SNe Ia appears to be higher in early-type galaxies than it is ingalaxies of later morphological types. This suggests that the ancestorsof SNe Ia-pec may differ systematically in age or composition from theprogenitors of normal SNe Ia. Unexpectedly, five SNe of Types Ib/c, II,and IIn (all of which are thought to have massive progenitors) are foundin host galaxies that are nominally classified as types E and S0.However, in each case the galaxy classification is uncertain, or newlyinspected images show evidence suggesting a later classification. Amongthese five objects, NGC 3720, the host galaxy of SN 2002at, wasapparently misidentified in the Carnegie Atlas of Galaxies.
| Supernova 2002ho in NGC 4210
IAUC 8011 available at Central Bureau for Astronomical Telegrams.
| Nearby Optical Galaxies: Selection of the Sample and Identification of Groups
In this paper we describe the Nearby Optical Galaxy (NOG) sample, whichis a complete, distance-limited (cz<=6000 km s-1) andmagnitude-limited (B<=14) sample of ~7000 optical galaxies. Thesample covers 2/3 (8.27 sr) of the sky (|b|>20deg) andappears to have a good completeness in redshift (97%). We select thesample on the basis of homogenized corrected total blue magnitudes inorder to minimize systematic effects in galaxy sampling. We identify thegroups in this sample by means of both the hierarchical and thepercolation ``friends-of-friends'' methods. The resulting catalogs ofloose groups appear to be similar and are among the largest catalogs ofgroups currently available. Most of the NOG galaxies (~60%) are found tobe members of galaxy pairs (~580 pairs for a total of ~15% of objects)or groups with at least three members (~500 groups for a total of ~45%of objects). About 40% of galaxies are left ungrouped (field galaxies).We illustrate the main features of the NOG galaxy distribution. Comparedto previous optical and IRAS galaxy samples, the NOG provides a densersampling of the galaxy distribution in the nearby universe. Given itslarge sky coverage, the identification of groups, and its high-densitysampling, the NOG is suited to the analysis of the galaxy density fieldof the nearby universe, especially on small scales.
| 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.
| Groups of galaxies. III. Some empirical characteristics.
Not Available
| Kinematics of the local universe. VII. New 21-cm line measurements of 2112 galaxies
This paper presents 2112 new 21-cm neutral hydrogen line measurementscarried out with the meridian transit Nan\c cay radiotelescope. Amongthese data we give also 213 new radial velocities which complement thoselisted in three previous papers of this series. These new measurements,together with the HI data collected in LEDA, put to 6 700 the number ofgalaxies with 21-cm line width, radial velocity, and apparent diameterin the so-called KLUN sample. Figure 5 and Appendices A and B forcorresponding comments are available in electronic form at thehttp://www.edpsciences.com
| 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.
| A revised catalog of CfA1 galaxy groups in the Virgo/Great Attractor flow field
A new identification of groups and clusters in the CfA1 Catalog ofHuchra et al. is presented, using a percolation algorithm to identifydensity enhancements. It is shown that in the resulting catalog,contamination by interlopers is significantly reduced. The Schechterluminosity function is redetermined, including the Malmquist bias.
| Optical positions and 327 MHz flux-densities of UGC galaxies in selected Westerbork fields
The study presents accurate optical positions of 421 UGC galaxies whichare used to search for 30 92-cm WSRT fields observed for emission fromthese galaxies. Good 92-cm flux densities were obtained for 140galaxies, marginal flux densities for 71 galaxies, and upper limits for210 galaxies. For 35 galaxies, spectral indices in the decimeterwavelength range are determined. The mean spectral index for spiralgalaxies (0.72 +/- 0.03) is very similar to that of elliptical galaxies(0.64 +/- 0.10). The four multiple systems in the sample have a muchflatter spectral index (-0.21 +/- 0.07), from which the presence of asignificant thermal component in their total radio emission issuggested. Comparison with IRAS results show that about half of thegalaxies detected at radio wavelengths are detected in the FIR. It isproposed that some spiral galaxies are anomalously weak in the IR ascompared with their radio brightness.
| 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.
| Groups of galaxies within 80 Mpc. II - The catalogue of groups and group members
This paper gives a catalog of the groups and associations obtained bymeans of a revised hierarchical algorithm applied to a sample of 4143galaxies with diameters larger than 100 arcsec and redshifts smallerthan 6000 km/s. The 264 groups of galaxies obtained in this way (andwhich contain at least three sample galaxies) are listed, with the looseassociations surrounding them and the individual members of eachaggregate as well; moreover, the location of every entity among 13regions corresponding roughly to superclusters is specified. Finally,1729 galaxies belong to the groups, and 466 to the associations, i.e.,the total fraction of galaxies within the various aggregates amounts to53 percent.
| The far-infrared properties of the CfA galaxy sample. I - The catalog
IRAS flux densities are presented for all galaxies in the Center forAstrophysics magnitude-limited sample (mB not greater than 14.5)detected in the IRAS Faint Source Survey (FSS), a total of 1544galaxies. The detection rate in the FSS is slightly larger than in thePSC for the long-wavelength 60- and 100-micron bands, but improves by afactor of about 3 or more for the short wavelength 12- and 25-micronbands. This optically selected sample consists of galaxies which are, onaverage, much less IR-active than galaxies in IR-selected samples. Itpossesses accurate and complete redshift, morphological, and magnitudeinformation, along with observations at other wavelengths.
| Arm classifications for spiral galaxies
The spiral arm classes of 762 galaxies are tabulated; 636 galaxies withlow inclinations and radii larger than 1 arcmin were classified on thebasis of their blue images on the Palomar Observatory Sky Survey (POSS),76 SA galaxies in the group catalog of Geller and Huchra were alsoclassified from the POSS, and 253 galaxies in high-resolution atlaseswere classified from their atlas photographs. This spiral armclassification system was previously shown to correlate with thepresence of density waves, and galaxies with such waves were shown tooccur primarily in the densest galactic groups. The present sampleindicates, in addition, that grand design galaxies (i.e., those whichtend to contain prominent density wave modes) are physically larger thanflocculent galaxies (which do not contain such prominent modes) by afactor of about 1.5. A larger group sample confirms the previous resultthat grand design galaxies are preferentially in dense groups.
| A search for environmental effects on the optical properties of galaxies in groups
Environmental density-related modifications of basic optical properties(luminosities, sizes, axial ratios, and colors) of galaxies belonging toGeller and Huchra's (1983) groups have been investigated. Remarkably, itis found that the broad maxima of the distributions of luminosities anddiameters of spirals and the whole corresponding distributions oflenticulars tend to move to lower values as one goes to groups of highcompactness, whereas the luminosity-diameter relationship of spiralstends to become flatter. No color and axial ratio differences betweengalaxies of high- and low-compactness groups have been detected.
| Morphology of spiral galaxies. I - General properties
Red Palomar Sky Survey plates are scanned to characterize a completesample of 605 spiral galaxies north of declination -33 deg havinginclination angle less than 56 deg and blue diameter 2-15 arcmin. Theselection of the data and the reduction and parameter-extractionprocedures are explained, and the data and the results of statisticalanalysis are presented in tables and graphs. Findings reported include alow frequency of occurrence for small inclination angles (suggestingdistortion of outer structures), similar distributions of central diskbrightness for types Sa-Sc but not for types Sd-Sm (where mean valuesare smaller), fewer late-type galaxies with large exponential-disk scalelengths, no galaxies with both high central brightness and large scalelength (indicating a limit on angular momentum in galaxy formation), anda correlation between mean surface brightness and absolute magnitude forlater-type galaxies but not for types Sa-Scd.
| The dependence on distance and redshift of the velocity vectors of the sun, the Galaxy, and the Local Group with respect to different extragalactic frames of reference
The solar apex S is confirmed to move steadily from S-prime toS-asterisk, when the mean redshift of the reference frame increases fromsmall to large values, on the basis of a new analysis of the solarmotion and Hubble ratio. Most of the change takes place in the 0-4000km/sec interval. The velocity vectors increase steadily, and thedirections of the apexes drift progressively as the mean distance orredshift of the reference frame increases. The frame of referencedefined by galaxies at z greater than 0.01 is essentially at rest withrespect to background radiation, suggesting that any intrinsic dipolaranisotropy of the background radiation is probably less than about0.0001.
| 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.
| A catalog of hierarchical subclustering in the Turner-Gott groups
Information on the substructure, to four levels of hierarchy, ispresented for the 103 groups listed by Turner and Gott (TG) in theircatalog of groups of galaxies. All galaxies brighter than Mpg= 14.0 in the region delta is 0 deg or greater and b(II) is 40 deg orgreater that have been assigned group memberships by TG are included.Also listed is the local environmental information for each of thegalaxies, giving the surface density enhancement beta in the galaxy'sneighborhood, calculated at 15 levels in the range beta = 4.6 to 10,000.
| Inner ring structures in galaxies as distance indicators. III - Distances to 453 spiral and lenticular galaxies
Abstract image available at:http://adsabs.harvard.edu/cgi-bin/nph-bib_query?1983ApJS...51..149B&db_key=AST
| Flocculent and grand design spiral structure in field, binary and group galaxies
A 12-division morphological system emphasizing arm continuity, lengthand symmetry has been developed for the classification of all spiralgalaxies according to the regularity of their spiral arm structure. Armclassifications were tabulated for 305 barred and nonbarred spiralgalaxies; of these, 79 are isolated, 52 are binary and 174 are ingroups. Among the isolated SA galaxies, 68 + or - 10% have irregular andfragmented, or 'flocculent', spiral structures. Only 32 + or - 10% havesymmetric spiral arms in the classic grand design pattern. Flocculentspirals are the most common structures of galaxies without companions orbars. Since flocculent galaxies may have bars and companions, and granddesign galaxies may have neither bars nor companions, such perturbationsare neither perfectly effective nor always necessary in the driving ofgrand design patterns.
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