目录
图像
上传图像
DSS Images Other Images
相关文章
Starbursts in barred spiral galaxies. VI. HI observations and the K-band Tully-Fisher relation
This paper reports a study of the effect of a bar on the neutralhydrogen (HI) content of starburst and Seyfert galaxies. We also makecomparisons with a sample of ``normal'' galaxies and investigate howwell starburst and Seyfert galaxies follow the fundamental scalingTully-Fisher (TF) relation defined for normal galaxies. 111 Markarian(Mrk) IRAS galaxies were observed with the Nançay radiotelescope,and HI data were obtained for 80 galaxies, of which 64 are newdetections. We determined the (20 and 50%) linewidths, the maximumvelocity of rotation and total HI flux for each galaxy. Thesemeasurements are complemented by data from the literature to form asample of Mrk IRAS (74% starburst, 23% Seyfert and 3% unknown) galaxiescontaining 105 unbarred and 113 barred ones. Barred galaxies have lowertotal and bias-corrected HI masses than unbarred galaxies, and this istrue for both Mrk IRAS and normal galaxies. This robust result suggeststhat bars funnel the HI gas toward the center of the galaxy where itbecomes molecular before forming new stars. The Mrk IRAS galaxies havehigher bias-corrected HI masses than normal galaxies. They also showsignificant departures from the TF relation, both in the B and K bands.The most deviant points from the TF relation tend to have a strongfar-infrared luminosity and a low oxygen abundance. These resultssuggest that a fraction of our Mrk IRAS galaxies are still in theprocess of formation, and that their neutral HI gas, partly of externalorigin, has not yet reached a stationary state.Based on observations obtained at the large radiotelescope ofObservatoire de Nançay, operated by Observatoire de Paris.Tables 5 and 6 are only (and Table 4 also) available in electronic format the CDS via anonymous ftp to cdsarc.u-strasbg.fr (130.79.128.5) orvia http://cdsweb.u-strasbg.fr/cgi-bin/qcat?J/A+A/416/515
| The PDS versus Markarian starburst galaxies: comparing strong and weak IRAS emitter at 12 and 25 μm in the nearby Universe
The characteristics of the starburst galaxies from the Pico dos Diassurvey (PDS) are compared with those of the nearby ultraviolet (UV)bright Markarian starburst galaxies, having the same limit in redshift(vh < 7500 km s-1) and absolute B magnitude(MB < -18). An important difference is found: theMarkarian galaxies are generally undetected at 12 and 25 μm in IRAS.This is consistent with the UV excess shown by these galaxies andsuggests that the youngest star-forming regions dominating thesegalaxies are relatively free of dust.The far-infrared selection criteria for the PDS are shown to introduce astrong bias towards massive (luminous) and large size late-type spiralgalaxies. This is contrary to the Markarian galaxies, which are found tobe remarkably rich in smaller size early-type galaxies. These resultssuggest that only late-type spirals with a large and massive disc arestrong emitters at 12 and 25 μm in IRAS in the nearby Universe.The Markarian and PDS starburst galaxies are shown to share the sameenvironment. This rules out an explanation of the differences observedin terms of external parameters. These differences may be explained byassuming two different levels of evolution, the Markarian being lessevolved than the PDS galaxies. This interpretation is fully consistentwith the disc formation hypothesis proposed by Coziol et al. to explainthe special properties of the Markarian SBNG.
| Far-Infrared Census of Starburst-Seyfert Connection
Far-infrared flux densities are newly extracted from the IRAS databasefor the Revised Shapley-Ames and CfA complete samples of Seyfertgalaxies. These data are used to classify the Seyfert galaxies intothose where the far-infrared continuum emission is dominated by theactive galactic nucleus (AGN), circumnuclear starburst, or host galaxy.While AGN-dominant objects consist of comparable numbers of Seyfert 1and 2 galaxies, starburst- and host-dominant objects consistpreferentially of Seyfert 2 galaxies. Thus, in addition to the dustytorus, the circumnuclear starburst region and host galaxy are importantin hiding the broad-line region. Morphologically, starburst-dominantSeyfert galaxies are of later types and more strongly interacting thanAGN-dominant Seyfert galaxies. In a later type galaxy, the AGN centralengine has a lower Eddington luminosity, and the gaseous content ishigher. The gas is efficiently supplied to the starburst via agalaxy-galaxy interaction. Morphologies of host-dominant Seyfertgalaxies are of various types. Since starbursts in Seyfert galaxies areolder than those in classical starburst galaxies, we propose anevolution from starburst to starburst-dominant Seyfert to host-dominantSeyfert for a late-type galaxy. An evolution from AGN-dominant Seyfertto host-dominant Seyfert is proposed for an early-type galaxy. Thesesequences have durations of a few times 108 yr and occurrepeatedly within a galaxy during its evolution from a late type to anearly type.
| Near-infrared spectroscopy of starburst galaxies
We present new K-band spectroscopy for a sample of 48 starburstgalaxies, obtained using UKIRT in Hawaii. This constitutes a fair sampleof the most common types of starburst galaxies found in the nearbyUniverse, containing galaxies with different morphologies, masses andmetallicities, with far-infrared luminosityLIR<1010Lsolar. The variety ofnear-infrared spectral features shown by these galaxies impliesdifferent bursts characteristics, which suggests that we survey galaxieswith different star formation histories or at different stages of theirburst evolution. Using synthetic starburst models, we conclude that theensemble of parameters that best describes starburst galaxies in thenearby UniverseQ1 is a constant rate of star formation, a Salpeterinitial mass function (IMF) with an upper mass cut-off ofMup=30Msolar and bursts ages between 10Myr and1Gyr. The model is fully consistent with the differences observed in theoptical and far-infrared (FIR) between the different types ofstarbursts. It suggests that Hii galaxies have younger bursts and lowermetallicities than starburst nucleus galaxies (SBNGs), while luminousinfrared galaxies (LIRGs) have younger bursts but higher metallicities.Although the above solution from the synthetic starburst model is fullyconsistent with our data, it may not constitute a strong constraint onthe duration of the bursts and the IMF. A possible alternative may be asequence of short bursts (which may follow an universal IMF) over arelatively long period of time. In favour of the multiple-bursthypothesis, we distinguish in our spectra some variations ofnear-infrared (NIR) features with the aperture that can be interpretedas evidence that the burst regions are not homogeneous in space andtime. We also found that the burst stellar populations are dominated byearly-type B stars, a characteristic which seems difficult to explainwith only one evolved burst. Our observations suggest that the starburstphenomenon must be a sustained or self-sustained phenomenon: either starformation is continuous in time, or multiple bursts happen in sequenceover a relatively long period of time. The generality of ourobservations implies that this is a characteristic of starburst galaxiesin the nearby Universe.
| Homogenization of the Stellar Population along Late-Type Spiral Galaxies
We present a study of the broadband UBV color profiles for 257 Sbcbarred and nonbarred galaxies, using photoelectric aperture photometrydata from the literature. Using robust statistical methods, we haveestimated the color gradients of the galaxies, as well as the total andbulge mean colors. A comparative photometric study using CCD images wasdone. In our sample, the color gradients are negative (reddish inward)in approximately 59% of the objects, are almost null in 27%, and arepositive in 14%, considering only the face-on galaxies, which representapproximately 51% of the sample. The results do not change, essentially,when we include the edge-on galaxies. As a consequence of this study wehave also found that barred galaxies are overrepresented among theobjects having null or positive gradients, indicating that bars act as amechanism of homogenization of the stellar population. This effect ismore evident in the U-B color index, although it can also be detected inthe B-V color. A correlation between the total and bulge colors wasfound that is a consequence of an underlying correlation between thecolors of bulges and disks found by other authors. Moreover, the meantotal color is the same irrespective of the gradient regime, whilebulges are bluer in galaxies with null or positive gradients, whichindicates an increase of the star formation rate in the central regionsof these objects. We have also made a quantitative evaluation of theamount of extinction in the center of these galaxies. This was doneusing the Wide Field Planetary Camera 2 (WFPC2) and the Near InfraredCamera and Multi-Object Spectrometer (NICMOS) Hubble Space Telescope(HST) archival data, as well as CCD B, V, and I images. We show thatalthough the extinction in the V-band can reach values up to 2 mag inthe central region, it is unlikely that dust plays a fundamental role inglobal color gradients. We found no correlation between color and O/Habundance gradients. This result could suggest that the color gradientsare more sensitive to the age rather than to the metallicity of thestellar population. However, the absence of this correlation may becaused by dust extinction. We discuss this result by considering apicture in which bars are a relatively fast, recurrent phenomenon. Theseresults are not compatible with a pure classical monolithic scenario forbulge and disk formation. On the contrary, they favor a scenario inwhich both these components are evolving in a correlated process inwhich stellar bars play a crucial role. Based partly on observationsmade at the Pico dos Dias Observatory (PDO/LNA-CNPq), Brazil.
| 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.
| Starbursts in barred spiral galaxies. V. Morphological analysis of bars
We have measured the bar lengths and widths of 125 barred galaxiesobserved with CCDs. The dependence of bar strength (identified with baraxis ratio) on morphological type, nuclear activity, central and mid-barsurface brightness is investigated. The properties of the bars are bestexplained if the sample is divided into early- (< SBbc) and late-typegalaxies, and into active (starburst, Seyfert or LINER) and normalgalaxies. We find that galaxies with very long bars are mostly activeand that normal late-type galaxies have a distinct behavior from thethree other groups of galaxies. We confirm earlier findings that activelate-type galaxies tend to have both stronger and longer bars thannormal ones. An important result of this paper is that early-typegalaxies do not share this behavior: they all tend to have strong bars,whether they are active or not. We also find correlations between barstrength and relative surface brightness in the middle and at the edgeof the bar, which are not followed by normal late-type galaxies. Theseresults are interpreted in the light of recent numerical simulations andparadigms about galaxy evolution. They suggest that normal late-typegalaxies represent the first stage of galaxy evolution, and that bars inearly- and late-type galaxies do not have the same properties becausethey have a different origin. Based on observations obtained at the 2meter telescope of Observatoire du Pic du Midi, operated by INSU (CNRS)
| The Supernova Rate in Starburst Galaxies
We conducted an optical CCD search for supernovae in a sample of 142bright [m(B) <= 16 mag], nearby (z<=0.03) starburst galaxies overthe period 1988 December to 1991 June, to a limiting R-band magnitude of18. Five supernovae were found, in all cases outside the host galaxy'snucleus. We determine supernova rates (in supernova units or SNU) in theextranuclear regions to be 0.7 h^2 SNU for Type Ia, 0.7 h^2 SNU for TypeIb/c, and ~0.6 h^2 SNU for Type II, with large uncertainties but upperlimits of 2.2 h^2, 2.5 h^2, and 1.7 h^2 SNU, respectively. These ratesare similar to those measured in ``normal'' galaxies. We found noevidence for a supernova-induced brightening in any galactic nucleusand, with a few reasonable assumptions, can place upper limits of 9 h^2,12 h^2, and 7 h^2 SNU on the rates of unobscured supernovae Types Ia,Ib/c, and II, respectively, inside the nuclei.
| Starbursts in barred spiral galaxies. III. Definition of a homogeneous sample of starburst nucleus galaxies
This paper presents optical long-slit spectroscopic observations of 105barred Markarian IRAS galaxies. These observations are used to determinethe spectral type (starburst or Seyfert) of emission-line regions in thenucleus and along the bar of the galaxies, in order to define ahomogeneous sample of Starburst Nucleus Galaxies (SBNGs). Our selectioncriteria (ultraviolet excess, far infrared emission and barredmorphology) have been very efficient for selecting star-forminggalaxies, since our sample of 221 emission-line regions includes 82%nuclear or extranuclear starbursts. The contamination by Seyferts is low(9%). The remaining galaxies (9%) are objects with ambiguousclassification (Hii or LINER). The dust content and Hα luminosityincrease towards the nuclei of the galaxies. No significant variation ofthe electron density is found between nuclear and bar Hii regions.However, the mean Hα luminosity and electron density in the barare higher than in typical disk Hii regions. We investigate differentmechanisms for explaining the excess of nitrogen emission observed inour starburst nuclei. There is no evidence for the presence of a weakhidden active galactic nucleus in our starburst galaxies. The cause ofthis excess is probably a selective enrichment of nitrogen in the nucleiof the galaxies, following a succession of short and intense bursts ofstar formation. Our sample of SBNGs, located at a mean redshift of ~0.015, has moderate Hα ( ~ 10(41) erg s(-1) ) and far infrared ( ~10(10) Lsun) luminosities. The types are distributed equallyamong early- and late-type giant spirals with a slight preference forSbc/Sc types because of their barred morphology. The majority (62%) ofSBNGs are isolated with no sign of gravitational interaction. In termsof distance, luminosity and level of interaction, SBNGs are intermediatebetween Hii galaxies and luminous infrared galaxies. Based onobservations obtained at the 1.93 meter telescope of Observatoire deHaute-Provence operated by INSU (CNRS). Tables 1, 3, 4, 5 and 6 are onlyavailable in electronic form at the CDS via anonymous ftp tocdsarc.u-strasbg.fr (130.79.128.5) or viahttp://cdsweb.u-strasbg.fr/Abstract.html
| 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.
| 21 CM H1 Line Spectra of Galaxies in Nearby Clusters
A compilation of HI line fluxes, systemic velocities and line widths ispresented for \Ndet detected galaxies, mostly in the vicinities of 30nearby rich clusters out to a redshift of z ~ .04, specifically for usein applications of the Tully-Fisher distance method. New 21 cm HI lineprofiles have been obtained for ~ 500 galaxies in 27 Abell clustersvisible from Arecibo. Upper limits are also presented for \Nnod galaxiesfor which HI emission was not detected. In order to provide ahomogeneous line width determination optimized for Tully-Fisher studies,these new data are supplemented by the reanalysis of previouslypublished spectra obtained both at Arecibo and Green Bank that areavailable in a digital archive. Corrections for instrumental broadening,smoothing, signal-to-noise and profile shape are applied, and anestimate of the error on the width is given. When corrected forturbulent broadening and viewing angle, the corrected velocity widthspresented here will provide the appropriate line width parameter neededto derive distances via the Tully-Fisher relation.
| Photoelectric UBV Photometry of 179 Bright Galaxies
This paper presents photoelectric UBV multiaperture photometry of 179bright galaxies that was used to compute total magnitudes and colorindices published in the Third Reference Catalog of Bright Galaxies(RC3). The observations were made at the McDonald Observatory from 1983December to 1986 September with an Amperex 56-DVP photometer attached tothe 0.76 and 0.91 m telescopes. The observations can also be used tocalibrate CCD images.
| 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.
| A multifrequency radio continuum and IRAS faint source survey of markarian galaxies
Results are presented from a multifrequency radio continumm survey ofMarkarian galaxies (MRKs) and are supplemented by IRAS infrared datafrom the Faint Source Survey. Radio data are presented for 899 MRKsobserved at nu = 4.755 GHz with the National Radio Astronomy Observatory(NRAO)-Green Bank 300 foot (91 m) telescope, including nearly 88% ofthose objects in Markarian lists VI-XIV. In addition, 1.415 GHzmeasurements of 258 MRKs, over 30% of the MRKs accessible from theNational Aeronomy and Ionosphere Center (NAIC)-Arecibo, are reported.Radio continuum observations of smaller numbers of MRKs were made at10.63 GHz and at 23.1 GHz and are also presented. Infrared data from theIRAS Faint Source Survey (Ver. 2) are presented for 944 MRKs, withreasonably secure identifications extracted from the NASA/IPACExtragalactic Database. MRKs exhibit the same canonical infraredcharacteristics as those reported for various other galaxy samples, thatis well-known enhancement of the 25 micrometer/60 micrometer color ratioamong Seyfert MRKs, and a clear tendency for MRKs with warmer 60micrometer/100 micrometer colors to also possess cooler 12 micrometer/25micrometer colors. In addition, non-Seyfert are found to obey thewell-documented infrared/radio luminosity correlation, with the tightestcorrelation seen for starburst MRKs.
| 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
| Gas content of infrared luminous markarian galaxies
The atomic and molecular hydrogen gas properties of a complete sample ofMarkarian galaxies with flux density at 60 µm higher than 1.95 Jyare presented. We present the improved far-infrared luminosity functionof Markarian galaxies; and its comparison with other samples. We findthat 40% of the bright IRAS galaxies of far-infrared luminosity higherthan 1010.5 L are Markarian galaxies. There is an absence of correlationbetween HI content of Markarian galaxies and current star formationactivity, implying that star formation in these systems has complexstructure and it is not a simple function of the HI content. On thecontrary, the H2 content of Markarian galaxies is well correlated withstar formation activity. It is argued that tight correlation between HIand H2 contents is a consequence of transformation of atomic hydrogeninto molecular.
| 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.
| 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.
| The small scale environment of low surface brightness disk galaxies
We use a sample of about 340 low surface brightness (LSB) disk galaxieswith measured redshifts in combination with the Center for Astrophysicsredshift survey to test the hypothesis that LSB galaxies have a deficitof nearby companion galaxies compared to high surface brightness (HSB)disk galaxies. We find a very strong statistical deficit of galaxieslocated within a projected radius of 0.5 Mpc and within a velocity of500 km/s around LSB disk galaxies compared to HSB ones. Further,comparing LSB and HSB disk galaxies which are located in the sameportion of the sky indicates that the average distance to the nearestneighbor is 1.7 times farther for LSB disk galaxies. AKomologorov-Smirnoff test rules out, at greater than the 99 percentconfidence level, the hypothesis that the distribution ofnearest-neighbor distances is the same for HSB and LSB disk galaxies. Wespeculate that LSB disk galaxies have relatively long formation timescales and therefore must form in relative isolation. In addition, thelack of tidal interactions over a Hubble time serves to suppress theoverall star-formation rate as no external trigger is available to helpclump the gas. The observed low surface densities of H I in combinationwith the low probability of tidal interactions effectively preventsthese disk galaxies from evolving very rapidly.
| A list of some corrections to Zwicky's Catalogue of Galaxies and Clusters of Galaxies
Not Available
| Long-slit spectroscopy of the central regions of starburst galaxies - Henize 2-10 and Markarian 52
Long-slit spectroscopic observations have been made for the twostarburst galaxies He 2-10 and Mrk 52, and the physical conditions ofthe starburst regions in galactic nuclei are discussed. H-alpha emissionis strongly concentrated in the central 70 and 300 pc regions in He 2-10and Mrk 52 respectively. This is evidence for nuclear starbursts in bothgalaxies. The H-alpha equivalent widths are 310 and 230 A for He 2-10and Mrk 52, respectively, values comparable to those of giant andsupergiant H II regions. Thus, the starburst phenomena that occurred inthe two nuclei continued for a comparable time to that of the OBassociations in giant and supergiant H II regions in disks. Based onforbidden S II double ratios, the electron densities of the nuclearionized regions in both galaxies are to the order of 1000/cu cm,decreasing outward to the order of 100/cm. The filling factors arecomparable to the highest values in giant and supergiant H II regions.
| Pairing properties of Markarian starburst Galaxies
The environmental parameters of 516 non-Seyfert Markarian galaxies werestudied in a redshift-bounded sample, supplemented by new spectra andredshift measures for possible companions, in order to evaluate theiroccurrence in galaxy pairs, defined through quantitative criteria. Itwas found that one-third of these galaxies occur in pairs (while only 6to 10 percent of optically-selected galaxies are known to be paired). Acomparison of various optical and IR properties of paired and nonpairedMarkarian galaxies showed no differences in the shape of the optical,far-IR, or H-alpha luminosity functions. It was found, however, that theMarkarian component is brighter than the other galaxy in each pair by0.66 magnitude in the mean at B.
| The cluster of galaxies SC 2008-57 (A 3667).
Abstract image available at:http://adsabs.harvard.edu/cgi-bin/nph-bib_query?1990RMxAA..21...52S&db_key=AST
| The color of the inner regions of Seyfert galaxies compared with normal galaxies
For homogeneous samples of 57 Seyfert and 79 normal galaxies, the (U-B)0and (B-V)0 color indices are determined for inner regions in rings witha mean radius of about 4 kpc. It is found that the E/S0-Sbc-type Seyfertgalaxies are bluer in (U-B)0 than similar normal galaxies. The positionof Seyfert galaxy rings on a two-color diagram reveals larger scatteringand a more systematic shift of points compared with the normal colorsequence of galaxies. It is suggested that these peculiarities arerelated to bursts of star formation and, in some objects, to large (B-V)color excesses in the inner part of the galaxy.
| Integrated colors and luminosity of Seyfert host galaxies - A comparison with the photometric characteristics of normal galaxies
Not Available
| 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 statistical study of properties of Seyfert and starburst galaxies
Spectral and morphological data for 282 Seyfert and emission-linegalaxies spanning radio to X-ray wavelengths are compiled. The datainclude a large number of optical emission-line measurements which havenot been reported previously. These data are intended to provide aconvenient summary of the relevant properties of these galaxies, as wellas a data base to search for correlations among the various parametersin order to obtain a better understanding of the active galaxyphenomenon. The paper presents the data and analyzes the distributionsof various properties of Seyfert 1 and Seyfert 2 galaxies and starburstgalaxies. It is found that Seyferts 2s have a higher 60 micron/forbiddenO III 5007 A flux ratio than Seyfert 1s. This result, combined with thefact that Seyfert 2s are more heavily reddened, indicate that they havea higher dust content. It is also found that starburst nuclei arecomparable to Seyfert 2s in far-infrared and 20 cm luminosities,although their optical spectra are markedly different.
| Long-slit spectroscopy of starburst galaxies
Long-slit spectroscopy of nine optically luminous starburst galaxies(SBGs) is presented that shows that star formation is not confined totheir nuclei, but extends up to kpc from their centers. This extendedemission, coupled with their narrow line widths and low ionization,morphologically and spectroscopically distinguish SBGs from AGN. Therotation curves and velocity profiles both suggest that the starformation occurs in a large, disk-shaped volume which is supported byrotation and contains from tens to thousands of separate, massive H IIregion complexes. Given the large spatial extent of the star formationand its disk environment, it is difficult to see how an evolutionarylink between SBGs and AGN could operate.
| Far-infrared luminosities of Markarian starburst galaxies. II - Individual galaxies
IRAS observations of galaxies in the Balzano sample of opticallyselected starburst nuclei and of a comparison of Virgo spiral galaxiesare used to derive far-infrared luminosities. Distances and blue andH-alpha luminosities of the starburst galaxies are also tabulated.
| 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.
|
提交文章
相关链接
提交链接
下列团体成员
|
观测天体数据
目录:
|
