Садржај
Слике
Уплоадјуј своје слике
DSS Images Other Images
Везани чланци
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 UZC-SSRS2 Group Catalog
We apply a friends-of-friends algorithm to the combined Updated ZwickyCatalog and Southern Sky Redshift Survey to construct a catalog of 1168groups of galaxies; 411 of these groups have five or more members withinthe redshift survey. The group catalog covers 4.69 sr, and all groupsexceed the number density contrast threshold, δρ/ρ=80. Wedemonstrate that the groups catalog is homogeneous across the twounderlying redshift surveys; the catalog of groups and their membersthus provides a basis for other statistical studies of the large-scaledistribution of groups and their physical properties. The medianphysical properties of the groups are similar to those for groupsderived from independent surveys, including the ESO Key Programme andthe Las Campanas Redshift Survey. We include tables of groups and theirmembers.
| Redshifts for 2410 Galaxies in the Century Survey Region
The Century Survey strip covers 102 deg2 within the limits8h5<=α<=16h5, 29.0d<=δ<=30.0d, equinoxB1950.0. The strip passes through the Corona Borealis supercluster andthe outer region of the Coma cluster. Within the Century Survey region,we have measured 2410 redshifts that constitute four overlappingcomplete redshift surveys: (1) 1728 galaxies with Kron-CousinsRph<=16.13 covering the entire strip, (2) 507 galaxieswith Rph<=16.4 in right ascension range8h32m<=α<=10h45m, equinox B1950.0, (3) 1251 galaxies withabsorption- and K-corrected RCCDc<=16.2 (where ``c''indicates ``corrected'') covering the right ascension range8h5<=α<=13h5, equinox B1950.0, and (4) 1255 galaxieswith absorption- and K-corrected VCCDc<=16.7 also coveringthe right ascension range 8h5<=α<=13h5, equinoxB1950.0. All these redshift samples are more than 98% complete to thespecified magnitude limit. We derived samples 1 and 2 from scans of thePOSS1 red (E) plates calibrated with CCD photometry. We derived samples3 and 4 from deep V and R CCD images covering the entire region. Weinclude coarse morphological types for all the galaxies in sample 1. Thedistribution of (V-R)CCD for each type correspondsappropriately with the classification. Work reported here is basedpartly on observations obtained at the Michigan-Dartmouth-MITObservatory.
| V- and R-band Galaxy Luminosity Functions and Low Surface Brightness Galaxies in the Century Survey
We use 64 deg2 of deep V and R CCD images to measure thelocal V- and R-band luminosity functions of galaxies. TheV0<16.7 and R0<16.2 redshift samples contain1255 and 1251 galaxies and are 98.1% and 98.2% complete, respectively.We apply k-corrections before the magnitude selection so that thecompleteness is to the same depth for all spectral types. The V and Rfaint-end slopes are surprisingly identical: α=-1.07+/-0.09.Representative Schechter function parameters for H0=100 are:M*R=-20.88+/-0.09,φ*R=0.016+/-0.003 Mpc-3 andM*V=-20.23+/-0.09,φ*V=0.020+/-0.003 Mpc-3. The V andR local luminosity densities,jR=(1.9+/-0.6)×108 Lsolar andjV=(2.2+/-0.7)×108 Lsolar, are inessential agreement with the recent 2 Degree Field Galaxy RedshiftSurvey and Sloan Digital Sky Survey determinations. All low surfacebrightness (LSB) galaxies fall in the large-scale structure delineatedby high surface brightness galaxies. The properties and surface numberdensity of our LSB galaxies are consistent with the LSB galaxy catalogof O'Neil, Bothun & Cornell, suggesting that our samples arecomplete for LSB galaxies to the magnitude limits. We measure colors,surface brightnesses, and luminosities for our samples, and find strongcorrelations among these galaxy properties. The color-surface brightnessrelation is(V-R)0=(-0.11+/-0.05)μR,0+(2.6+/-0.9).
| The QDOT all-sky IRAS galaxy redshift survey
We describe the construction of the QDOT survey, which is publiclyavailable from an anonymous FTP account. The catalogue consists ofinfrared properties and redshifts of an all-sky sample of 2387 IRASgalaxies brighter than the IRAS PSC 60-μm completeness limit(S_60>0.6Jy), sparsely sampled at a rate of one-in-six. At |b|>10deg, after removing a small number of Galactic sources, the redshiftcompleteness is better than 98per cent (2086/2127). New redshifts for1401 IRAS sources were obtained to complete the catalogue; themeasurement and reduction of these are described, and the new redshiftstabulated here. We also tabulate all sources at |b|>10 deg with noredshift so far, and sources with conflicting alternative redshiftseither from our own work, or from published velocities. A list of 95ultraluminous galaxies (i.e. with L_60μm>10^12 L_solar) is alsoprovided. Of these, ~20per cent are AGN of some kind; the broad-lineobjects typically show strong Feii emission. Since the publication ofthe first QDOT papers, there have been several hundred velocity changes:some velocities are new, some QDOT velocities have been replaced by moreaccurate values, and some errors have been corrected. We also present anew analysis of the accuracy and linearity of IRAS 60-μm fluxes. Wefind that the flux uncertainties are well described by a combination of0.05-Jy fixed size uncertainty and 8per cent fractional uncertainty.This is not enough to cause the large Malmquist-type errors in the rateof evolution postulated by Fisher et al. We do, however, find marginalevidence for non-linearity in the PSC 60-μm flux scale, in the sensethat faint sources may have fluxes overestimated by about 5per centcompared with bright sources. We update some of the previous scientificanalyses to assess the changes. The main new results are as follows. (1)The luminosity function is very well determined overall but is uncertainby a factor of several at the very highest luminosities(L_60μm>5x10^12L_solar), as this is where the remainingunidentified objects are almost certainly concentrated. (2) Thebest-fitting rate of evolution is somewhat lower than our previousestimate; expressed as pure density evolution with density varying as(1+z)^p, we find p=5.6+/-2.3. Making a rough correction for the possible(but very uncertain) non-linearity of fluxes, we find p=4.5+/-2.3. (3)The dipole amplitude decreases a little, and the implied value of thedensity parameter, assuming that IRAS galaxies trace the mass, isΩ=0.9(+0.45, -0.25). (4) Finally, the estimate of density varianceon large scales changes negligibly, still indicating a significantdiscrepancy from the predictions of simple cold dark matter cosmogonies.
| 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 Dynamics of Poor Systems of Galaxies
We assemble and observe a sample of poor galaxy systems that is suitablefor testing N-body simulations of hierarchical clustering and otherdynamical halo models. We (1) determine the parameters of the densityprofile rho(r) and the velocity dispersion profile sigma_p(R), (2)separate emission-line galaxies from absorption-line galaxies, examiningthe model parameters and as a function of spectroscopic type, and (3)for the best-behaved subsample, constrain the velocity anisotropyparameter, beta, which determines the shapes of the galaxy orbits. Oursample consists of 20 systems, 12 of which have extended X-ray emissionin the ROSAT All-Sky Survey. We measure the 877 optical spectra ofgalaxies brighter than m_R~15.4 within 1.5 h^-1 Mpc of the systemcenters (we take H_0=100 h km s^-1 Mpc^-1). Thus, we sample the systemmembership to a radius typically three times larger than other recentoptical group surveys. The average system population is 30 galaxies, andthe average line-of-sight velocity dispersion is ~300 km s^-1. TheNavarro, Frenk, & White universal profile and the Hernquist modelboth provide good descriptions of the spatial data. In most cases anisothermal sphere is ruled out. Systems with declining sigma_p(R) arewell-matched by theoretical profiles in which the star-forming galaxieshave predominantly radial orbits (beta>0) many of these galaxies areprobably falling in for the first time. There is significant evidencefor spatial segregation of the spectroscopic classes regardless ofsigma_p(R).
| 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.
| Large-Scale Structures in the Zone of Avoidance: The Galactic Anticenter Region
Abstract image available at:http://adsabs.harvard.edu/cgi-bin/nph-bib_query?1995ApJ...449..527L&db_key=AST
| Apparent magnitudes of galaxies behind the Milky Way
There are many Infrared Astronomy Satellite (IRAS) Uppsala GeneralCatalogue of Galaxies (UGC) and IRAS/Catalogue of Galaxies and ofClusters of Galaxies (CGCG) galaxies with measured redshifts in theMilky Way region at absolute value of b less than 15 deg. We compare themagnitudes of these galaxies with those of IRAS/UGC and IRAS/CGCGgalaxies located at b = 30 deg to 45 deg having similar redshift values.Eighteen redshifts of the latter objects were newly measured by us. Thebrightnesses of the galaxies systematically decrease with Galacticlatitude at the Milky Way region. It is shown that IRAS galaxies withincz less than 10000 km/sec are mostly detected in the regions behind theMilky Way with N(H I) less than 5 x 1021/sq cm if theredshifts are measured down to 21 mag in blue magnitude.
| The extended 12 micron galaxy sample
We have selected an all-sky (absolute value of b greater than or equalto 25 deg) 12 micron flux-limited sample of 893 galaxies from the IRASFaint Source Catalog, Version 2 (FSC-2). We have obtained accurate totalfluxes in the IRAS wavebands by using the ADDSCAN procedure for allobjects with FSC-2 12 micron fluxes greater than 0.15 Jy and increasingflux densities from 12 to 60 microns, and defined the sample by imposinga survey limit of 0.22 Jy on the total 12 micron flux. Its completenessis verified, by means of the classical log N - log S andV/Vmax tests, down to 0.30 Jy, below which we have measuredthe incompleteness down to the survey limit, using the log N - log Splot, for our statistical analysis. We have obtained redshifts (mostlyfrom catalogs) for virtually all (98.4%) the galaxies in the sample.Using existing catalogs of active galaxies, we defined a subsample of118 objects consisting of 53 Seyfert 1s and quasars, 63 Seyfert 2s, andtwo blazars (approximately 13% of the full sample), which is the largestunbiased sample of Seyfert galaxies ever assembled. Since the 12 micronflux has been shown to be about one-fifth of the bolometric flux forSeyfert galaxies and quasars, the subsample of Seyferts (includingquasars and blazars) is complete not only to 0.30 Jy at 12 microns butalso with respect to a bolometric flux limit of approximately 2.0 x10-10 ergs/s/sq cm. The average value of V/Vmaxfor the full sample, corrected for incompleteness at low fluxes, is 0.51+/- 0.04, expected for a complete sample of uniformly distributedgalaxies, while the value for the Seyfert galaxy subsample is 0.46 +/-0.10. We have derived 12 microns and far-infrared luminosity functionsfor the AGNs, as well as for the entire sample. We extracted from oursample a complete subsample of 235 galaxies flux-limited (8.3 Jy) at 60microns. The 60 micron luminosity function computed for this subsampleis in satisfactory agreement with the ones derived from the brightgalaxy sample (BGS) and the deep high-galactic latitude sample, bothselected at 60 microns.
| Millimeter and submillimeter continuum emission from early-type galaxies
Twenty-two early-type galaxies that were detected by IRAS have beensearched for continuum emission at millimeter and submillimeterwavelengths using the James Clerk Maxwell Telescope (JCMT). IRAS wasrelatively insensitive to cold dust that emits primarily at these longerwavelengths. In this first survey we were able to detect or achieveuseful limits on the emission from 14 of the 22 galaxies observed. Fromthese data we estimate upper limits on the dust temperature and lowerlimits on the mass of dust within the JCMT beam. These results arecompared with H I and CO data and with the blue luminosities of thegalaxies. The results are consistent with a model where the dust-to-gasratio is similar to the Galactic one, and the amount of cold dust is anorder of magnitude greater than the amount of warm dust (as is also seenin our Galaxy). The total dust mass, normalized to the luminosity of theentire galaxy, is much lower than is found in spiral galaxies, asexpected.
| 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.
| The neutral hydrogen content of early type disk galaxies
This paper presents the results of a sensitive 21-cm survey of massiveearly type galaxies made with the Arecibo radio telescope. Of the 81galaxies observed, the detections comprise 48 percent of the S0s, 73percent of the S0a's, and 96 percent of the Sa's. The values of thehybrid, distance-independent H I surface densities of the S0 galaxies inthe sample ranged continuously from amounts comparable to the mostgas-rich Sa galaxies to low estimated upper limts of the H I content.CCD images of most of the gas-rich S0s revealed either faint spiralfeatures or patchy structure in the disks. While no firm correlationbetween H I content and environmental density is apparent for thegalaxies in the sample, two-sample statistics suggest a differencebetween the highest and the lowest density bins. Early-type diskgalaxies within low density environments tend to have higher gas surfacedensities than those within high-density environments.
| Less probable IRR II candidateas
The paper presents a list of 89 less probable Irr candidates in whichthe presence of dust is suspected. In a commentary to this list, theshape of the galaxies is described and their location in relation toneighboring background galaxies is noted.
| Groups of galaxies in the Center for Astrophysics redshift survey
By applying the Huchra and Geller (1982) objective group identificationalgorithm to the Center for Astrophysics' redshift survey, a catalog of128 groups with three or more members is extracted, and 92 of these areused as a statistical sample. A comparison of the distribution of groupcenters with the distribution of all galaxies in the survey indicatesqualitatively that groups trace the large-scale structure of the region.The physical properties of groups may be related to the details oflarge-scale structure, and it is concluded that differences among groupcatalogs may be due to the properties of large-scale structures andtheir location relative to the survey limits.
| 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 model for far-IR emission of non-Seyfert Markarian galaxies
The paper presents simple models for the FIR emission from extended H IIregions and from cooler dust heated by the general interstellarradiation field. The models account for a realistic grain-sizedistribution including PAH molecules. In addition, the model explainsthe observed correlation between the FIR to optical luminosity ratio andthe 60-10 micron colors.
| A study of a flux-limited sample of IRAS galaxies
Redshift data and accurate four-color infrared photometry are presentedfor a complete IRAS sample of galaxies brighter than 2 Jy at 60 microns.A simple power law provides a good fit to the distribution forluminosities from 10 to the 10th to 10 to the 12th solar. There is noindication of an exponential dropoff in the luminosity function at highenergies. A flattening of the luminosity function occurs at L less than10 to the 20th solar. The highest luminosity galaxies typically arefound in multiple, possibly interacting, systems and exhibit marginallynarrower infrared spectral energy distributions than the isolatedspirals which predominate at low luminosities. Infrared-bright galaxiescome from a different population than the majority of optically brightgalaxies. In particular, galaxies of low blue luminosity are not stronginfrared emitters.
| 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.
| Structure of superclusters and superclusters formation. IV Spatial distribution of clusters of galaxies in the Coma supercluster and its large-scale environment
The Coma-A1367 Supercluster and its large-scale environment areinvestigated. The Zwicky et al. (1961-68) clusters are used assupercluster tracers; superclusters are defined not by visual impressionbut on the basis of cluster analysis. Attention is restricted to an areaof the sky where RA is between 9h and 15h, with Dec. greater than -3deg. Clustering analysis is applied to study the spatial distribution.At neighborhood radii R = 15-25 Mpc (for Hubble constant H = 50 km per sper Mpc), the clusters form chains and superclusters of galaxies. It isnoted that at R = 26-28 Mpc, superclusters merge to a single connectednetwork. Cluster chains link the Coma-A1367 Supercluster with the LocalSupercluster, A779, and Hercules Superclusters. The Coma-A1367Supercluster comprises four cluster chains, and its diameter is greaterthan 100 Mpc. It is noted that a typical cluster chain has eight Zwickyclusters and is 80 Mpc in length. Most, if not all, of the clusters formconnected systems. Empty regions devoid of clusters have diameters up to100 Mpc in this region of the sky. The morphology distribution of brightgalaxies and the mean absolute magnitude of first ranked galaxies inZwicky clusters are found to be similar to the respective quantities inAbell clusters.
| 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.
| Radial velocities of galaxies detected in the Arecibo 2380 MHz survey
The Loiano telescope's image tube spectrograph was used to obtain thepreviously unknown radial velocities of 50 galaxies detected during theArecibo 2380 MHz survey of bright galaxies, leading to the determinationof 224 radio-detected galaxy redshifts north of 15 deg. Both a 100km/sec typical standard error and minus 60 plus or minus 20 km/secsystematic zero error are derived for the velocities presented, on thebasis of comparisons with other redshift sources made on a furthersample of 35 galaxies.
|
Додај нови чланак
Линкови у сродству са темом
Додај нови линк
Чланови следећих група \:
|
Посматрања и Астрометриски подаци
Каталог и designations:
|
