Ýçindekiler
Görüntüler
Resim Yükleyin
DSS Images Other Images
Ýlgili Makaleler
XMM-Newton observations of the interacting galaxy pairs NGC 7771/0 and NGC 2342/1
We present XMM-Newton X-ray observations of the interacting galaxy pairsNGC 7771/7770 and NGC 2342/2341. In NGC 7771, for the first time we areable to resolve the X-ray emission into a bright central source plus twobright (LX > 1040 erg s-1)ultraluminous X-ray sources (ULXs) located either end of the bar. In thebright central source (LX~ 1041 ergs-1), the soft emission is well-modelled by a two-temperaturethermal plasma with kT= 0.4/0.7 keV. The hard emission is modelled witha flat absorbed power-law (Γ~ 1.7, NH~ 1022cm-2), and this together with a low-significance (1.7σ)~ 300 eV equivalent width emission line at ~6 keV are the firstindications that NGC 7771 may host a low-luminosity AGN. For the barULXs, a power-law fit to X-1 is improved at the 2.5σ level withthe addition of a thermal plasma component (kT~ 0.3 keV), while X-2 isimproved only at the 1.3σ level with the addition of a discblackbody component with Tin~ 0.2 keV. Both sources arevariable on short time-scales implying that their emission is dominatedby single accreting X-ray binaries (XRBs). The three remaining galaxies,NGC 7770, NGC 2342 and NGC 2341, have observed X-ray luminosities of0.2, 1.8 and 0.9 × 1041 erg s-1,respectively (0.3-10 keV). Their integrated spectra are alsowell-modelled by multi-temperature thermal plasma components with kT=0.2-0.7 keV, plus power-law continua with slopes of Γ= 1.8-2.3that are likely to represent the integrated emission of populations ofXRBs as observed in other nearby merger systems. A comparison with otherisolated, interacting and merging systems shows that all four galaxiesfollow the established correlations for starburst galaxies betweenX-ray, far-infrared and radio luminosities, demonstrating that theirX-ray outputs are dominated by their starburst components.
| 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
| Physical Coupling of Kazarian Galaxies with Surrounding Galaxies
Results from a statistical study of Kazarian galaxies and the objectssurrounding them are presented. It is shown that: (1) the sample ofKazarian galaxies up to 16m.0 is complete. (2) Roughly 35.7% of theKazarian galaxies are members of clusters, 14.0% of groups, and 13.6% ofbinary systems, while 36.7% are single galaxies. (3) Of the 580 Kazariangalaxies, roughly 61.2% are infrared, 8.8% radio, and 2.8% x-raysources. (4) The relative numbers of Kazarian galaxies for completesamples of I, R, and X in the different groups are systematically higherthan the corresponding numbers for samples of all Kazarian galaxies.
| 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.
| 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.
| The Luminous Starburst Ring in NGC 7771: Sequential Star Formation?
Only two of the 20 highly luminous starburst galaxies analyzed by Smithet al. exhibit circumnuclear rings of star formation. These galaxiesprovide a link between ~10^11 L_solar luminosity class systems andclassical, less-luminous ringed systems. In this paper, we report thediscovery of a near-infrared counterpart to the 1.6 kpc diameter nuclearring of radio emission in NGC 7771 (UGC 12815). The ring contains ~10radio-bright clumps and ~10 near-infrared-bright clumps. A displacementbetween the peaks of the radio and the near-infrared emission indicatesthe presence of multiple generations of star formation. The estimatedthermal emission from each radio source is equivalent to that of ~35,000O6 stars. Each near-infrared-bright knot contains ~5000 red supergiants,on average. In the case that the radio-bright knots are 4 Myr old andthe near-infrared-bright knots are ~10 Myr old, each knot ischaracterized by a stellar mass of 10^7 M_solar, and the impliedtime-averaged star formation rate is ~40 M_solar yr^-1. Severalsimilarities are found between the properties of this system and otherringed and nonringed starbursts. Morphological differences between NGC7771 and the starburst+Seyfert 1 galaxy NGC 7469 (UGC 12332) suggestthat NGC 7771 may not be old enough to fuel an active galactic nucleus(AGN), or may not be capable of fueling an AGN. Alternatively, thedifferences may be unrelated to the presence or absence of an AGN andmay simply reflect the possibility that star formation in rings isepisodic.
| 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.
| Morphological classification of new galaxies with a UV excess
The results of a morphological classification of 580 galaxies with a UVexcess, included in the lists in [M. A. Kazarian, Astrofizika,15, 5(1979); ibid.,15, 193 (1979); M. A. Kazarian and É. S. Kazarian,ibid.,16, 17 (1980); ibid.,18, 512 (1982); ibid.,19, 213 (1983)], arepresented. For this we have developed a set of symbols, using the typesE, S, and Ir introduced by Hubble, as well as symbols introduced byother authors and us. This set enabled us to make the morphologicalclassification. Direct photographs obtained on the 2.6-m and 6-mtelescopes were used to classify 141 of the galaxies (over 24%), whilePalomar Atlas charts were used for the remaining 439 galaxies. Thesegalaxies were divided into two groups based on classificationconditions, and data on each group are given in Tables 1 and 2,respectively. The results for each group, given in Table 3, show thatwith the transition from early types, such as C and E, to later types,such as S and Ir, the relative number of galaxies going into one group(Table 1), in which the classification was based on direct photographs,increases in comparison with the number going into the other group(Table 2).
| Transport de particules et atmospheres d'etoiles magnetiques
We present the results of a spectral study of 17 galaxies with UV excessfrom the lists of [1-3]. We determine the equivalent widths of lines,the relative intensities of emission lines for 3 galaxies, the electrondensities of the gas components of 9 galaxies, and the gas masses of 2galaxies. It is shown that the gas component of Galaxy No. 235 hasextremely low excitability. In the spectrum of this galaxy the lines[Fell] 4951, 4947 are seen to be distinct, not merging with the line[OIII] 4959. The line H in the spectrum of Galaxy No. 128 has twoemission peaks, which seem to have been formed by an absorptioncomponent midway between the lines. The line H in the spectrum of GalaxyNo. 350 is detected both in emission and absorption, the absorptioncomponent lying in the longwave part of the line.
| A survey of the Pisces-Perseus supercluster. VI - The declination zone +15.5 deg to 21.5 deg
New results are presented of Arecibo observations in the 21 cm line of765 galaxies with declinations between 15.5 deg and 21.5 deg, in thePisces-Perseus supercluster zone. If considered independently on theneighboring parts of sky, this region, to the South of the superclusterridge, shows significantly less evidence of structure on large scales inexcess of 30 Mpc, contrasting substantially with the characteristics ofthe declination zones immediately to the North.
| 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.
| 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.
| Spectral observations of new galaxies with ultraviolet excess.
The results are given of spectral observations of 42 galaxies withultraviolet excess. Spectra were obtained with the 6-m telescope of theSpecial Astrophysical Observatory of the USSR Academy of Sciences withUAGS the spectrograph in conjunction with a scanner. Emission lines areobserved in the spectra of 27 galaxies; one object, No. 82, exhibits thefeatures of Seyfert galaxies. In the spectrum of galaxy No. 188 linesare not observed in the fairly wide wavelength interval 3550-7130 A.
| New galaxies with high surface brightness in the Nilson system
Using Arkelian's criteria (1974, 1975), data for 47 new High SurfaceBrightness Galaxies (HSBG) in the system of the Uppsala GeneralCatalogue of Galaxies are presented. Of the 193 Arkelian galaxies listedin the catalog, 46 were also found to be HSBGs in the Nilson system(1973). The present list contains 19 Zwicky (1971) compact galaxies (40percent), two of which are listed as HSBGs by Nilson.
| KISO survey for ultraviolet-excess galaxies. V.
Presented here are the fifth list and identification charts of theultraviolet-excess galaxies which have been detected on the multi-colorplates taken with the Kiso Schmidt telescope for 10 survey fields. Inthe sky area of some 300 square degrees 628 objects are catalogued downto the photographic magnitude of about 17.5.
| 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.
| Accurate Optical Positions of Arakelian Galaxies
Abstract image available at:http://adsabs.harvard.edu/cgi-bin/nph-bib_query?1981AJ.....86..820K&db_key=AST
| Galaxies of high surface brightness
Two lists are presented which contain 621 galaxies whose surfacebrightness, as derived from their apparent magnitudes, is at least 22.0magnitudes from an area of 1 sq arcsec. The lists were compiled in anattempt to verify observationally a possible correlation between surfacebrightness and nuclear activity. Four percent of all the galaxies in anarea of 4.5 sr at declinations higher than -3 deg and galactic latitudesgreater than 20 deg are listed, including 30 Markarian, 29 Zwicky, and 7blue Haro galaxies. A morphological study of 130 of the galaxiesindicates that about half are elliptical or lenticular, 50 are compactor peculiar, and that there is an excess of elliptical and lenticularobjects in comparison with a random sample. Notes on the morphologicaltypes and colors of the galaxies are provided along with identificationcharts.
|
Yeni bir Makale Öner
Ýlgili Baðlantýlar
Yeni Bir Baðlantý Öner
sonraki gruplarýn üyesi:
|
Gözlemler ve gökölçümü verileri
Kataloglar ve belirtme:
|
