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The galaxy cluster Abell 426 (Perseus). A catalogue of 660 galaxy positions, isophotal magnitudes and morphological types
We present a homogeneous catalogue of galaxies in the field of thenearby galaxy cluster A 426 (Perseus) based on a survey of digitisedSchmidt plates taken with the Tautenburg 2 m telescope in the B band.Accurate positions, morphological types, B25 isophotalmagnitudes, angular radii and position angles are given for 660 galaxieswithin a field of about 10 square-degrees, centred on alpha = 3() h 21()min, delta = 41degr 33' (J2000). When available, the radial velocity andthe most common name taken from NED or PGC are included. The cataloguecomprises galaxies brighter than B25~19.5. The estimatedlimit of completeness is B25~18. Two thirds of the galaxiesare published for the first time. The galaxy positions are measured witha mean accuracy of 0farcs5 , the photometric accuracy is of the order of0.1 to 0.2 mag depending on image crowding and galaxy shape.Morphological properties were evaluated from the visual inspections ofboth deep images obtained from the digital co-addition of a large numberof plates and higher-resolution images from single plates taken undergood seeing conditions. The superimposed images unveil faint structuresdown to mu_B ~ 27 mag arcsec(-2) . The catalogue is applied to a studyof statistical properties of the galaxies in A 426: projecteddistribution of morphological types, segregation of morphological types,position of the cluster centre, distribution of galaxy position angles,type-dependent luminosity functions, and total B-luminosity of the thecluster. In agreement with previous studies, we find a relativespiral-deficiency in the central region (r <~ 30'). The percentage ofidentified S+Irr increases, however, increases from 30% in the centre tomore than 50% in the outer parts. The projected distributions of early-and late-type galaxies are not co-centred. The total luminosity of allsupposed member galaxies in the surveyed area is estimated to(6.5+/-0.9)\ 10(12) x h50(-2) blue solar luminosities. We donot analyse in detail possible substructures in the projecteddistribution of galaxies. However, we found a pronounced clump ofgalaxies at alpha (J2000.0) = 3() h20fm4 , delta (J2000.0) = 43degr4 ',which is shown to be a background cluster at z~ 0.050. The catalogue isonly available in electronic form at the CDS via anonymous ftp tocdsarc.u-strasbg.fr ( or viahttp://cdsweb.u-strasbg.fr/Abstract.html } \fnmsep \thanks{ Based onobservations made with the 2\,m telescope of the ThüringerLandessternwarte Tautenburg, Germany, and with the 2.2\,m telescope ofthe German-Spanish Astronomical Centre, Calar Alto, Spain.

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.

Multifrequency radio continuum observations of head-tail galaxies in the Perseus cluster
New observations of head-tail radio galaxies in the Perseus cluster at21, 49 and 92 cm using the WSRT are presented. Two new head-tailgalaxies were discovered bringing the total for the cluster to five. Weshow total intensity maps for all of them and spectral indexdistribution and polarization maps for NGC 1265 and IC 310. Theobservations with high dynamic range, obtained with the WSRT and theredundancy and self-calibration techniques, reveal a large extension ofthe tail of NGC 1265 both at 49 cm and at 92 cm. The projected tailbends over an angle of almost 360°. There are several cleardifferences between the bright and the faint part of the radio tail:within a distance of one or two resolution beams the intensity decreasesby more than an order of magnitude and the spectral index steepens from-1 to -2. The simplest model for the tail is that it delineates theorbit of the galaxy through the cluster. Because the tail is seen inprojection, the faint part of the tail is visible only when it is notsuperimposed onto the bright part of the tail. It is likely, however,that large scale motions of the hot intracluster medium also help shapethe tail. In this respect it is interesting to note that the tails ofboth NGC 1265 and IC 310, as well as the low brightness emission of NGC1275 appear to have their faint extensions shifted to the east. The verylong tail of NGC 1265 makes it possible to test at low frequenciesmodels of the ageing process of the radiating electrons. In the faintpart of the tail the brightness temperature is very low, which eitherindicates a very weak magnetic field or a large deviation fromequipartition between particle and magnetic energy. The most remarkableproperties of the faint part of the tail of NGC1265, namely its constantsurface brightness and spectral index, are compared with threesynchrotron ageing models, making some standard assumptions. All thesemodels disagree with either the data or one of the assumptions. TheKardashev-Pacholczyk model and the Komissarov-Gubanov model requiremagnetic fields stronger than the equipartition value; the Jaffe-Perolamodel and the Komissarov-Gubanov model require an additional process,like in situ reacceleration or bulk streaming motions of electrons inthe tail, far in excess of a plausible galaxy speed, to explain theobserved spectra.

Kopf-Schwanz-Radioquellen. Proben fur das intergalaktische Medium.
Not Available

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.

Tailed radio sources as probes of the intergalactic medium pressure
The study analyzes a sample of tailed radio galaxies in Abell clustersin order to estimate their internal pressure under the assumption thattheir tails are in static equilibrium with the thermal pressure of theambient X-ray emitting gas. When projection effects are not taken intoaccount, the external pressure Pth is a factor from 5 to 100larger than the minimum internal nonthermal pressure, Peq,evaluated under equipartition conditions with a volume filling factorand a ratio between relativistic protons and electrons both equal toone. A statistical method is developed to take the projection effectsinto account. The internal pressure is set equal to s x Peq,with s as a free parameter, and the distance of each galaxy from thecluster center is determined by imposing s x Peq -Pth, where Pth is inferred from the availableX-ray data. Acceptable values of s fall in the range 5-10. Theimplications of this result are briefly discussed.

Alignments of galaxies in the Perseus supercluster
The relative orientations of the galaxies belonging to the Perseussupercluster are investigated. The result is a lack of alignment in anypreferred direction of the supercluster galaxies (ellipticals, spiralsand both), except in a selected region of the supercluster, whosesignificance is low. Moreover no evidence of anisotropy in the relativeorientations of neighboring galaxies has been found.

Photoelectric Observations of Interacting and Compact Galaxies
Not Available

Redshift-magnitude bands and the evolution of galaxies. I - New observations
Well-defined samples of galaxy redshifts and magnitudes for the Perseusand A1367 clusters are obtained from a combination of new and existingobservations. For the Perseus cluster, identifications, 1950 positions,distance from cluster center in degrees, mp and V(6)magnitudes, redshifts corrected for earth orbital and galactic rotation,and comments are provided. Information for the 50 central A1367 galaxiesincludes identification, mp, redshift and redshift source,morphology, and comments.

Dynamics of the Perseus Cluster of Galaxies
Abstract image available at:http://adsabs.harvard.edu/cgi-bin/nph-bib_query?1971ApJ...168..321C&db_key=AST

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Observation and Astrometry data

Right ascension:03h17m17.00s
Aparent dimensions:0.955′ × 0.676′

Catalogs and designations:
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NGC 2000.0NGC 1259

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