Home     Getting Started     To Survive in the Universe    
Inhabited Sky
    News@Sky     Astro Photo     The Collection     Forum     Blog New!     FAQ     Press     Login  

NGC 7594



Upload your image

DSS Images   Other Images

Related articles

The Updated Zwicky Catalog (UZC)
The Zwicky Catalog of galaxies (ZC), with m_Zw<=15.5, has been thebasis for the Center for Astrophysics (CfA) redshift surveys. To date,analyses of the ZC and redshift surveys based on it have relied onheterogeneous sets of galaxy coordinates and redshifts. Here we correctsome of the inadequacies of previous catalogs by providing (1)coordinates with <~2" errors for all of the 19,369 catalog galaxies,(2) homogeneously estimated redshifts for the majority (98%) of the datataken at the CfA (14,632 spectra), and (3) an estimate of the remaining``blunder'' rate for both the CfA redshifts and for those compiled fromthe literature. For the reanalyzed CfA data we include a calibrated,uniformly determined error and an indication of the presence of emissionlines in each spectrum. We provide redshifts for 7257 galaxies in theCfA2 redshift survey not previously published; for another 5625 CfAredshifts we list the remeasured or uniformly rereduced value. Among ournew measurements, 1807 are members of UZC ``multiplets'' associated withthe original Zwicky catalog position in the coordinate range where thecatalog is 98% complete. These multiplets provide new candidates forexamination of tidal interactions among galaxies. All of the newredshifts correspond to UZC galaxies with properties recorded in the CfAredshift compilation known as ZCAT. About 1000 of our new measurementswere motivated either by inadequate signal-to-noise in the originalspectrum or by an ambiguous identification of the galaxy associated witha ZCAT redshift. The redshift catalog we include here is ~96% completeto m_Zw<=15.5 and ~98% complete (12,925 galaxies out of a total of13,150) for the right ascension ranges 20^h>=alpha_1950<=4^h and8^h>=alpha_1950<=17^h and declination range-2.5d<=delta_1950<=50^deg. This more complete region includes allof the CfA2 survey as analyzed to date. The Great Wall structurepersists throughout the northern survey region. Dedicated to the memoryof Jim Peters, whose friendship, skill, and dedication were essential tothis work.

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 CFA Redshift Survey: Data for the South Galactic CAP
We present redshifts for a sample of 4391 galaxies with magnitudem_B(0)<=15.5 covering 20^h<=alpha<=4^h in right ascension and-2.5d<=delta<=90^deg in declination. This sample is complete forall galaxies in the merge of the Zwicky et al. and Nilson catalogs inthe south Galactic cap. Redshifts for 2964 of these were measured aspart of the second CfA Redshift Survey. The data reveal large voids inthe foreground and background of the Perseus-Pisces Supercluster. Thelargest of these voids lies at a mean velocity ~8000 km s^-1, hasdiameter ~5000 km s^-1, and is enclosed by a complex of densestructures. The large structure known as the Perseus-Pisces Superclusterforms the near side of this complex. On the far side of this large void,at a mean velocity ~12,000 km s^-1, there is another coherent densewall. The structures in this survey support the view that galaxiesgenerally lie on surfaces surrounding or nearly surrounding low-densityregions or voids.

A Catalog of Nearby Poor Clusters of Galaxies
A catalog of 732 optically selected, nearby poor clusters of galaxiescovering the entire sky north of -3 deg declination is presented. Thepoor clusters, called WBL clusters, were identified as concentrations ofthree or more galaxies with photographic magnitudes brighter than 15.7,possessing a galaxy surface overdensity of 104/3. Thesecriteria are consistent with those used in the identification of theoriginal Yerkes poor clusters, and this new catalog substantiallyincreases the sample size of such objects. These poor clusters cover theentire range of galaxy associations up to and including Abell clusters,systematically including poor and rich galaxy systems spanning over 3orders of magnitude in the cluster mass function. As a result, this newcatalog contains a greater diversity of richness and structures thanother group catalogs, such as the Hickson and Yerkes catalogs. Theinformation on individual galaxies includes redshifts andcross-references to other galaxy catalogs. The entries for the clustersinclude redshift (where available) and cross-references to other groupand cluster catalogs.

Galaxy coordinates. II. Accurate equatorial coordinates for 17298 galaxies
Using images of the Digitized Sky Survey we measured coodinates for17298 galaxies having poorly defined coordinates. As a control, wemeasured with the same method 1522 galaxies having accurate coordinates.The comparison with our own measurements shows that the accuracy of themethod is about 6 arcsec on each axis (RA and DEC).

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

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.

Optical Rotation Curves and Linewidths for Tully-Fisher Applications
Abstract image available at:http://adsabs.harvard.edu/cgi-bin/nph-bib_query?1997AJ....114.2402C&db_key=AST

Deep r-Band Photometry for Northern Spiral Galaxies
We present r-band surface photometry for 349 northern Sb-Sc UGCgalaxies, from a total of 627 CCD images. For each galaxy, we presentsurface brightness profiles, isophotal and total magnitudes, isophotalradii, and structural parameters from exponential fits to the disk. Onehundred ninety-five galaxies have been observed more than once. Allnights with a photometric transformation scatter greater than 0.022 magwere rejected. Sky errors are investigated carefully and yield profilesthat are reliable down to 26 r mag arcsec^-2^, Deep isophotal magnitudesare as accurate as +/-0.019, and extrapolated magnitudes are internallyconsistent to within 0.020. We compare visual (UGC) and CCD isophotaldiameters and show that axial ratio must be included as a thirdparameter. Comparison with the r-band CCD photometry of Kent andWillick, and accounting for sky errors, suggest typical errors for totalmagnitudes of +/-0.08. Our data are also shown to be zero-pointed on thesame Gunn r system as that of Kent and Willick. Ellipticity measurementsagree very well except for progressively face-on galaxies where spiralstructure is more conspicuous. The ellipticity internal error is lessthan 0.02, or about 3^deg^ for inclinations. Our internal extinctioncorrection implies that disks are semitransparent in their outer parts.We caution that comparison of central surface brightnesses and scalelengths is complicated by the subjective nature of their measurement;extreme care must be applied when using such quantities. We measure anapparent Freeman law of (μ_0,c_) = 20.08 +/- 0.55 r mag arcsec^-2^.This magnitude-limited sample was originally derived for studies oflarge-scale motions in the local universe. The deep CCD photometry isalso ideally suited for matching spectroscopic studies, mass modeling,galaxy structural analysis, etc.

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.

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.

Peculiar motions in superclusters: Perseus--Pisces
We discuss the near infrared observations obtained for a set of 81galaxies in the region of the Perseus--Pisces supercluster. From these,in conjunction with the 21 cm data of the Arecibo sample, we estimatethe peculiar velocities via the Tully-Fisher relation and the model ofthe local perturbations as derived by Han and Mould. From the datadiscussed we find that the supercluster main structure is shrinking. Toexplain the size and velocities observed the model requires, for thesupercluster, a mean overdensity of about delta rho/rho = 9 whichcorresponds to a total mass of 1016 solar masses to cover anextension of about 100 Mpc.

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.

A catalog of radio, optical, and infrared observations of spiral galaxies in clusters
The results of a major observational program on the luminosities,colors, and gas contents of spiral galaxies in clusters of galaxies arepresented. The data have been used as part of a detailed investigationinto the nature of cluster spirals and for revisions of the distancescale using the infrared Tully-Fisher relation. The observationalstrategies, reduction procedures, and sources or error are brieflydiscussed. The data include 21-cm H I observations, UBVR multiaperturephotometry, and H-band photometry of several hunderd spiral galaxies in10 clusters.

Submit a new article

Related links

  • - No Links Found -
Submit a new link

Member of following groups:

Observation and Astrometry data

Right ascension:23h18m11.40s
Aparent dimensions:0.661′ × 0.288′

Catalogs and designations:
Proper Names   (Edit)
NGC 2000.0NGC 7594
ICIC 5307

→ Request more catalogs and designations from VizieR