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

NGC 2227



Upload your image

DSS Images   Other Images

Related articles

The mass distribution in the innermost regions of spiral galaxies
We use high-spatial resolution ( ~ 100 pc) rotation curves of 83 spiralgalaxies to investigate the mass distribution of their innermost kpc. Weshow that in this region the luminous matter completely accounts for thegravitational potential and no dark component is required. The derivedI-band disk mass-to-light ratios Y_I agree well with those obtained frompopulation synthesis models and correlate with color in a similar way.We find strict upper limits of ~ 10^7 M_Sun for the masses of compactbodies at the center of spirals ruling out that these systems host theremnants of the quasar activity.

The I-Band Tully-Fisher Relation for SC Galaxies: 21 Centimeter H I Line Data
A compilation of 21 cm line spectral parameters specifically designedfor application of the Tully-Fisher (TF) distance method is presentedfor 1201 spiral galaxies, primarily field Sc galaxies, for which opticalI-band photometric imaging is also available. New H I line spectra havebeen obtained for 881 galaxies. For an additional 320 galaxies, spectraavailable in a digital archive have been reexamined to allow applicationof a single algorithm for the derivation of the TF velocity widthparameter. A velocity width algorithm is used that provides a robustmeasurement of rotational velocity and permits an estimate of the erroron that width taking into account the effects of instrumental broadeningand signal-to-noise. The digital data are used to establish regressionrelations between measurements of velocity widths using other commonprescriptions so that comparable widths can be derived throughconversion of values published in the literature. The uniform H I linewidths presented here provide the rotational velocity measurement to beused in deriving peculiar velocities via the TF method.

The I-Band Tully-Fisher Relation for SC Galaxies: Optical Imaging Data
Properties derived from the analysis of photometric I-band imagingobservations are presented for 1727 inclined spiral galaxies, mostly oftypes Sbc and Sc. The reduction, parameter extraction, and errorestimation procedures are discussed in detail. The asymptotic behaviorof the magnitude curve of growth and the radial variation in ellipticityand position angle are used in combination with the linearity of thesurface brightness falloff to fit the disk portion of the profile. TotalI-band magnitudes are calculated by extrapolating the detected surfacebrightness profile to a radius of eight disk scale lengths. Errors inthe magnitudes, typically ~0.04 mag, are dominated by uncertainties inthe sky subtraction and disk-fitting procedures. Comparison is made withthe similar imaging database of Mathewson, Ford, & Buchhorn, both aspresented originally by those authors and after reanalyzing theirdigital reduction files using identical disk-fitting procedures. Directcomparison is made of profile details for 292 galaxies observed incommon. Although some differences occur, good agreement is found,proving that the two data sets can be used in combination with onlyminor accommodation of those differences. The compilation of opticalproperties presented here is optimized for use in applications of theTully-Fisher relation as a secondary distance indicator in studies ofthe local peculiar velocity field.

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.

A catalogue of spatially resolved kinematics of galaxies: Bibliography
We present a catalogue of galaxies for which spatially resolved data ontheir internal kinematics have been published; there is no a priorirestriction regarding their morphological type. The catalogue lists thereferences to the articles where the data are published, as well as acoded description of these data: observed emission or absorption lines,velocity or velocity dispersion, radial profile or 2D field, positionangle. Tables 1, 2, and 3 are proposed in electronic form only, and areavailable from the CDS, via anonymous ftp to cdsarc.u-strasbg.fr (to130.79.128.5) or via http://cdsweb.u-strasbg.fr/Abstract.html

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

Scaleheights of 486 southern spiral galaxies and some statistical correlation
Based on Peng's method (1988), we obtain scaleheights of 486 southernspiral galaxies, the images of which are taken from the Digitized SkySurvey at Xinglong Station of Beijing Astronomical Observatory. Thefitted spiral arms of 70 galaxies are compared with their images to gettheir optimum inclinations. The scaleheights of other 416 ones arelisted in Table A1 in Appendix. After compiling and analyzing the data,we find some statistical correlations. The most interesting results arethat a flatter galaxy is bluer and looks brighter, and galaxies becomeflatter along the Hubble sequence Sab -- Scd. Based on photographic dataof the National Geographic Society -- Palomar Observatory Sky Survey(NGS-POSS) obtained using the Oschin Telescope Palomar Mountain. TheNGS-POSS was funded by a grant from the National Geographic Society tothe California Institute of Technology. The plates were processed intothe present compressed digital form with their permission. The DigitizedSky Survey was produced at the Space Telescope Science Institute underUS Government grant NAG W-2166. Table A1 is available in electronic fromonly, via anonymous ftp orhttp://cdsweb.u-strasbg.fr/Abstract.html

Parameters of 2447 Southern Spiral Galaxies for Use in the Tully-Fisher Relation
I-band luminosities, rotational velocities, and redshifts of 1092 spiralgalaxies have been measured by CCD photometry and Hα spectroscopyusing the 1 m and 2.3 m telescopes at Siding Spring Observatory,respectively. The results are tabulated. Luminosity profiles andHα rotation curves are given for the galaxies. When these resultsare combined with similar data for 1355 spiral galaxies publishedpreviously (Mathewson, Ford, & Buchhorn, hereafter Paper I), itprovides a large, uniform, and unique data set with which to measure,via the Tully-Fisher relation, the peculiar velocities of galaxies inthe local universe to a distance of 11,000 km s^-1^ (Mathewson &Ford). Taking advantage of the opportunity for publishing this data inmachine-readable form, in the CD-ROM, we have also included similar datafor the 1355 galaxies in Paper I.

Constraining the Ages of Supernova Progenitors. I. Supernovae and Spiral Arms
We present the first results of a three-part study of supernova (SN)ages using positional age indicators in spiral galaxies. We havemeasured the positions of 90 Spectroscopically identified Type Ia andType II SNs (SNs Ia and SNs II) relative to spiral arms in their hostgalaxies, making a special effort to reduce inhomogeneity in the processof arm tracing for different galaxies. We find that SNs II are moretightly concentrated to the arms than SNs Ia, but both kinds of SNsoccur closer to arms than a random disk population. However, whencompared with the distribution of V and I light relative to the arms,the SNs Ia are no more tightly concentrated than the general stellarpopulation. This indicates that SNs Ia occur in a population old enoughto have diffused away from their formation regions.

Rotation Curves of 967 Spiral Galaxies
We present the rotation curves of 967 southern spiral galaxies, obtainedby deprojecting and folding the raw Hα data originally publishedby Mathewson, Ford, & Buchhorn (1992). For 900 objects, we alsopresent, in figures and tables, the rotation curves smoothed on scalescorresponding to 5%-20% of the optical size; of these, 80 meet objectiveexcellence criteria and are suitable for individual detailed massmodeling, while 820, individually less compelling mainly because of themoderate statistics and/or limited extension, are suitable forstatistical studies. The remaining 67 curves suffer from severeasymmetries, small statistics, and large internal scatter that maylargely limit their use in galaxy structure studies. The deprojectedfolded curves, the smoothed curves, and various related quantities areavailable via anonymous ftp at galileo.sissa.it in the directory/users/ftp/pub/psrot.

Distribution of supernovae relative to spiral arms and H II regions
We have studied the association of supernovae in spiral galaxies withsites of recent stars formation -- sprial arms and H II regions. It isshown that supernovae (SNe) of Types Ia, Ib, and II exhibitconcentration to spiral arms and their distributions over the distanceto the nearest spiral arm do not differ significantly. This result isconfirmed by a Kolmogorov-Smirnov test comparison with the distancedistributions, expected if SNe are distributed randomly inside the modelgalaxy. SNe of types Ib and II show a strong concentration towards H IIregions, while distribution of SNe Ia can be explained by chancesuperposition. All studied distributions of SNe Ib and II show strikingsimilarity, which suggests that their progenitors are massive stars withsimilar ages and initial masses. The association of SNe Ia with spiralarms suggests that their progenitors in spiral galaxies are likely to beintermediate mass stars.

Searching for supernovae--Visually and otherwise
The main features of visual searching for supernovae in other galaxiesby amateur astronomers are described, and an outline is given of theresults which have been achieved so far by this method. A shortcomparison is made between visual searching and photographic searching.A more extensive comparison is then made between visual searching forsupernovae in Australia, and the work of the Berkeley AutomaticSupernova Search at Leuschner Observatory, since 1986. Among theconclusions is the claim that a competent visual observer could producesimilar results to those produced by the Berkeley group if a telescopeof similar aperture was used for a similar amount of observing time, andfrom a good observing site. Indeed, visual searching might possiblyproduce more results, and such a search would only cost a small fractionof what was spent on this automatic search. It would be a worthwhileproject to conduct a visual search with a suitably desinged 76-cmtelescope, or a one metre telescope, over a period of a few years, tosee if this conclusion could be supported in practice.

Evidence for Ni-56 yields Co-56 yields Fe-56 decay in type IA supernovae
In the prevailing picture of Type Ia supernovae (SN Ia), their explosiveburning produces Ni-56, and the radioactive decay chain Ni-56 yieldsCo-56 yields Fe-56 powers the subsequent emission. We test a centralfeature of this theory by measuring the relative strengths of a (Co III)emission feature near 5900 A and a (Fe III) emission feature near 4700A. We measure 38 spectra from 13 SN Ia ranging from 48 to 310 days aftermaximum light. When we compare the observations with a simple multilevelcalculation, we find that the observed Fe/Co flux ratio evolves asexpected when the Fe-56/Co-56 abundance ratio follows from Ni-56 yieldsCo-56 yields Fe-56 decay. From this agreement, we conclude that thecobalt and iron atoms we observe through SN Ia emission lines areproduced by the radioactive decay of Ni-56, just as predicted by a widerange of models for SN Ia explosions.

A southern sky survey of the peculiar velocities of 1355 spiral galaxies
The paper presents data from photometric and spectroscopic observationsof 1355 southern spiral galaxies and uses them to determine theirdistances and peculiar velocities via the Tully-Fisher (TF) relation.I-band CCD surface photometry was carried out using the 1-m and 3.9-mtelescopes at Siding Spring Observatory. H-alpha rotation curves for 965galaxies and 551 H I profiles are presented. The physical parameters,photometric and velocity data, distances, and peculiar velocities of thegalaxies are presented in tabular form. The mean distance, systemicvelocity, and average peculiar velocity of 24 clusters in the sample aregiven. TF diagrams are presented for each cluster.

High rate for Type IC supernovae
Using an automated telescope, 20 SNe in carefully documentedobservations of nearby galaxies were detected. The SN rates for latespiral (Sbc, Sc, Scd, and Sd) galaxies, normalized to a blue luminosityof 10 exp 10 are 0.4, 1.6, and 1.1 h squared per 100 years for Types Ia,Ic, and II SNe. The rate for Type Ic SNe is significantly higher thanfound in previous surveys. The rates are not corrected for detectioninefficiencies and do not take into account the indications that the IcSNe are fainter on the average than the previous estimates; thereforethe true rates are probably higher. The rates are not strongly dependenton the galaxy inclination, in contradiction to previous compilations. Ifthe Milky Way is a late spiral, then the rate of the Galactic SNe isgreater than 1 per 30 +/-7 yr, assuming h = 0.75. This high rate hasencouraging consequences for future neutrino and gravitational waveobservatories.

The Asiago Supernova Catalogue
A Catalogue of Supernovae (SNe) is presented which tabulates the maindata relative to all extragalactic SNe discovered up to 1988 December31, and to their parent galaxies. In total 661 SNe are listed of which267 are classified. For an easier consultation, two lists are givenwhere the SNe are ordered chronologically and by Right Ascension,respectively. The overall distribution of classified supernovae over themorphological types of their parent galaxies is also presented in asummary table.

Deep photometry of supernovae
Photometric observations of SNs have been initiated at intermediate andlate stages, extending to much fainter limits the extensive SN survey ofRosino over the last 30 years. The correspondence between observed andestimated magnitudes via linear decline for the objects of the sample isjudged to be good. Before ascertaining the intrinsic object properties,the reddening due to the galactic and internal absorption of the parentgalaxy must be taken into account. Also noted are the features of SN1986 g in NGC 5128.

Medium resolution spectroscopy of the Supernova 1986 O in the spiral galaxy NGC 2227
The ESO Faint Object Spectrograph and Camera (EFOSC) was used onFebruary 1 and 2, 1987, at the 3.6 m telescope on La Silla to obtainimages and spectra of the SN 1986 O in the barred spiral galaxy NGC2227. From the CCD exposure through a V filter it is derived a magnitudeof 16.03; an H-alpha exposure is used to identify the H II regions inthe galaxy. The spectra cover the spectral range 4000-7800 A at aresolving power of 1900. Both the magnitude and the spectral featuresare consistent with the classification of the SN as a type Ia about 45days past maximum light. Strong interstellar lines of Na I are detectedat the velocity of NGC 2227. This feature, common to other three recenttype I supernovae, suggests that their progenitors might belong to adisk population.

The First Supplement to a Checklist of Supernovae in the NGC and IC Galaxies through 1985
This is the first supplement to the author's paper, "A Checklist ofSupernovae in the NGC and IC Galaxies Through 1985" (Spratt 1986).

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.

BV photometry and radial velocities of southern spiral galaxies
Multiaperture photoelectric photometry for 119 southern spiral galaxiesand heliocentric velocities for 98 southern spiral galaxies obtainedfrom image-tube spectrograms are presented. The data were collected in1976, 1977, and 1978 at Cerro Tololo Inter-American Observatory. Themagnitude and (B-V) color index are compared with aperture diameter inorder to determine if the present data correlate with previousmeasurements. The comparison reveals that the data correspond. Theinternal measurement error of the radial velocities is estimated; it isobserved that the internal error for one measurement is 41 km/sec.

Southern Galaxy Catalogue.
Not Available

Submit a new article

Related links

  • - No Links Found -
Submit a new link

Member of following groups:

Observation and Astrometry data

Constellation:Canis Major
Right ascension:06h25m57.90s
Aparent dimensions:2.291′ × 1.259′

Catalogs and designations:
Proper Names   (Edit)
NGC 2000.0NGC 2227

→ Request more catalogs and designations from VizieR