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1.
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2.
The results of a statistical investigation of bright galaxies with a UV excess are given. The data obtained for them are compared with those for normal galaxies. A list of bright galaxies (mpg ≤14m.5 ) with a UV excess has been compiled, numbering 461. Their absolute stellar magnitudes and average geometrical linear diameters were determined. The relationships between Mpg and log D are given for galaxies with a UV excess and normal galaxies. The graphs of the relationships are expressed by second-degree equations. It is shown that the UV evolutionary stage of the galaxies has no influence on the relationship between Mpg and log D. Translated from Astrofizika, Vol. 43, No. 1, pp. 21-32, January–March, 2000.  相似文献   

3.
A fifth list of objects from the BIG (Byurakan-IRAS galaxies) sample is given: 89 galaxies identified with 59 point sources from the IRAS Point Source Catalog. The identifications were based on the Digital Sky Survey (DSS), the First Byurakan Survey, blue and red maps from the Palomar Observatory Sky Survey, and infrared fluxes at 12, 25, 60, and 100 mm in the region of+65° ≤ δ ≤69δ and 5h10m ≤ α ≤9h 15m with an area of 96 deg2. For the identified galaxies the optical coordinates, their departures from the IR coordinates, and the stellar V magnitudes, morphological types, angular sizes, and position angles were determined. The objects have optical magnitudes in the range of 14m. 1-21m.5 and angular sizes in the range of 2″-47″. The galaxies are mainly spiral in morphology. Compact galaxies and Seyfert candidates, interacting pairs, “mergers,” galaxies with companions and superassociations, groups of galaxies (including compact ones), and others are encountered, which shows the importance of these objects for the study of the relationships among the phenomena of star formation, activity, and interactions. Finder charts from the DSS are given for these objects. New designations and numbering are introduced for galaxies in the studied sample. Translated from Astrofizika, Vol. 43, No. 3, pp. 425-441, July– September, 2000. The NASA/IPAC Extragalactic Database (NED), operated by the Jet Propulsion Laboratory, California Institute of Technology, under contract with NASA.  相似文献   

4.
A fourth list of optically identified point sources from the IRAS Point Source Catalog, containing 34 nonstellar objects, is given. The identifications were made on the basis of the Digitized Sky Survey (DSS), the First Byurakan Survey, blue and red maps from the Palomar Sky Survey (FBS), and infrared fluxes at 12, 25, 60, and 100 μm in the region of +61° ≤ δ ≤ 65° and 11h15m ≤ α ≤ 18h35m with an area of 200 sq. deg. For the identified objects we determined their optical coordinates, their departures from the IR coordinates, their stellar V magnitudes, color indices CI, and preliminary types. The optical magnitudes of the objects are in the range 12m.5-27m. The identified galaxies include Seyfert candidates, interacting pairs, galaxies with companions, superassociations, etc. The galaxies are encountered in groups in many cases, and the IR emission may be due to heating of intergalactic matter within a group. Finder charts from the DDS are given for these objects. Translated from Astrofizika, Vol. 41, No. 3, pp. 359–366, July–September, 1998.  相似文献   

5.
Part three of optically identified point sources from the IRAS Point Source Catalog contains 113 objects. The identifications were based on the Digitized Sky Survey (DSS), the First Byurakan Survey, blue and red maps from the Palomar Sky Survey, and infrared fluxes at 12, 25, 60, and 100 μm in the region of +61° ≤ δ ≤ + 65° and 11h15m ≤ α ≤ 18h35m with an area of 200 sq. deg. Of the 119 sources in this region, 6 could not be identified owing to the absence of optical counterparts with the given coordinates. For the identified objects we determined their optical coordinates, their departures from the IR coordinates, and their stellar V magnitudes, color indices (CI), and preliminary types. The objects have optical magnitudes in the range of 8n–21m. Of the 113 objects, 31 turned out to be stars of spectral types K and M, 1 is a planetary nebula, 2 are candidates to be quasi- stellar objects, and 79 are galaxies. A list of the 48 nonstellar objects is given. The identified galaxies include Seyfert candidates, interacting pairs, galaxies with companions, superassociations, etc. The galaxies are in groups in many cases, and the IR emission may be due to heating of intergalactic matter within a group. Finder charts for these objects from the DSS are given. Translated from Astrofizika, Vol. 41, No. 2, pp. 251–262, April-June, 1998.  相似文献   

6.
We present the coordinates, apparent magnitudes, and morphological types for 230 galaxies presumably identified with HIPASS (HI Parkes All-Sky Survey) sources. The new optical counterparts of the HIPASS sources follow the well-known statistical relationships between the hydrogen mass, luminosity, and type of galaxies. Low-surface-brightness galaxies constitute a significant fraction among these objects. The median value of the hydrogen mass-to-luminosity ratio for them is a factor of 2 or 3 higher than that for bright HIPASS galaxies, reaching 1.7M ⊙/L ⊙. A number of our objects are located near the boundary log(M HI/L B ) = 0.2(M B + 20) that defines the zone of gravitational stability of disk galaxies against large-scale star formation.  相似文献   

7.
The second portion of optically identified point sources from the IRAS Point Source Catalog contains 104 objects. The identifications were made on the basis of the Digitized Sky Survey (DSS), the First Byurakan Survey (FBS), blue and red maps of the Palomar Survey (POSS), and infrared fluxes at wavelengths of 12, 25, 60, and 100 fim in the region of +61 ° ≤ δ ≤ +65°and 50h30m ≤ α ≤ 11h15m with an area of 157 sq. deg. Of the 114 sources in this region, 10 could not be identified because of the absence of the corresponding optical counterparts with the given coordinates. For the identified objects we determined their optical coordinates, their departure from the IR coordinates, the stellar V magnitudes, the color indices CI, and the preliminary types. The objects have optical magnitudes in the range of 8n–21m. Of the 104 objects, 46 turned out to be stars of spectral types K and M, 1 is a planetary nebula, 3 are QSO candidates, and 54 are galaxies. In the present work we give a list of the 58 nonstellar objects. The identified galaxies include Seyfert candidates, interacting pairs, galaxies with companions and superassociations, etc. Finder charts for these objects from the DSS are given. Translated from Astrofizika, Vol. 40, No. 4, pp. 581–593, October-December, 1997.  相似文献   

8.
In the framework of study of the evolutionary status of galaxies in the nearby Lynx-Cancer void, we present the results of the SAO RAS 6-m telescope spectroscopy for 20 objects in this region. The principal faint line [Oiii]λ4363 Å, used to determine the electron temperature and oxygen abundance (O/H) by the classicalmethod, is clearly detected in only about 2/3 of the studied objects. For the remaining galaxies this line is either faint or undetected. To obtain the oxygen abundances in these galaxies we as well apply the semi-empirical method by Izotov and Thuan, and/or the empirical methods of Pilyugin et al., which are only employing the intensities of sufficiently strong lines. We also present our O/H measurements for 22 Lynx-Cancer void galaxies, for which the suitable Sloan Digital Sky Survey (SDSS) spectra are available. In total, we present the combined O/H data for 48 Lynx-Cancer void galaxies, including the data adopted from the literature and our own earlier results. We make a comparison of their locations on the (O/H)-MB diagram with those of the dwarf galaxies of the Local Volume in the regions with denser environment. We infer that the majority of galaxies from this void on the average reveal an about 30% lower metallicity. In addition, a substantial fraction (not less than 10%) of the void dwarf galaxies have a much larger O/H deficiency (up to a factor of 5). Most of them belong to the tiny group of objects with the gas metallicity Z ⊙/20 or 12+log(O/H)?7.35. The surface density of very metal-poor galaxies (Z ⊙/10) in this region of the sky is 2–2.5 times higher than that, derived from the emission-line galaxy samples in the Hamburg-SAO and the SDSS surveys. We discuss possible implications of these results for the galaxy evolution models.  相似文献   

9.
We present the results of a photometric study of 85 objects from the updated sample of galaxies residing in the nearby Lynx-Cancer void. We perform our photometry on u, g, r, and i-band images of the Sloan Digital Sky Survey. We determine model-independent galaxy parameters such as the integrated magnitudes and colors, effective radii and the corresponding surface brightness values, optical radii and Holmberg radii. We analyze the radial surface brightness profiles to determine the central brightness values and scale lengths of the model disks. We analyze the colors of the outer parts of the galaxies and compare them with model evolutionary tracks computed using the PEGASE 2 software package. This allowed us to estimate the time T SF elapsed since the onset of star formation, which turned out to be on the order of the cosmological time T 0 for the overwhelming majority of the galaxies studied. However, for 13 galaxies of the sample the time T SF does not exceed T 0/2 ～ 7 Gyr, and for 7 of them T SF ? 3.5 Gyr. The latter are mostly unevolved objects dominated by low-luminosity galaxies with M B > ?13.2. We use the integrated magnitudes and colors to estimate the stellar masses of the galaxies.We estimate the parameter M(H I)/L B and the gas mass fractions for void galaxies with known HI-line fluxes. A small subgroup (about 10%) of the gas-richest void galaxies with M(H I)/L B ? 2.5 has gas mass fractions that reach 94–99%. The outer regions of many of these galaxies show atypically blue colors. To test various statistical differences between void galaxies and galaxies from the samples selected using more general criteria, we compare some of the parameters of void galaxies with similar data for the sample of 195 galaxies from the Equatorial Survey (ES) based on a part of the HIPASS blind HI survey. The compared samples have similar properties in the common luminosity interval ?18.5<M g < ?13.5. The faintest void galaxies differ appreciably from the ES survey galaxies. However, the ES survey also contains about 7% of the so-called “inchoate” galaxies with highM(H I)/L B ratios, most of which are located far from massive neighbors and are probably analogs of void galaxies.  相似文献   

10.
The physical nature of 277 ultraviolet excess objects of the third Asiago field (22 square degrees, 15 ≦ mpg ≦ 18, U–B ≦≦ -0.2) is investigated on the basis of objective prism plates. Most of them are stars, 8% are quasar candidates and 7% compact galaxies. The proportions of different kinds of objects changes with the magnitude and U–B colour index. The surface density of quasars is estimated to be between 0.5 Q/sq. deg. and 1.0 Q/sq. deg. for the UVX A3 objects. The results of the A3 field (located in the Virgo cluster of galaxies) statistically agree with the ones of the A1 field, outside clusters of galaxies.  相似文献   

11.
The determination of the supernova (SN) rate is based not only on the number of detected events, but also on the properties of the parent galaxy population. This is the first paper of a series aimed at obtaining new, refined, SN rates from a set of five SN surveys, by making use of a joint analysis of near-infrared (NIR) data. We describe the properties of the 3838 galaxies that were monitored for SNe events, including newly determined morphologies and their DENIS, and POSS-II/UKST I, 2MASS and DENIS J and Ks and 2MASS H magnitudes. We have compared 2MASS, DENIS and POSS-II/UKST IJK magnitudes in order to find possible systematic photometric shifts in the measurements. The DENIS and POSS-II/UKST I band magnitudes show large discrepancies (mean absolute difference of 0.4 mag.), mostly due to different spectral responses of the two instruments, with an important contribution (0.33 mag rms) from the large uncertainties in the photometric calibration of the POSS-II and UKST photographic plates. In the other wavebands, the limiting near infrared magnitude, morphology, and inclination of the galaxies are the most influential factors which affect the determination of photometry of the galaxies. Nevertheless, no significant systematic differences have been found between any pair of NIR magnitude measurements, except for a few percent of galaxies showing large discrepancies. This allows us to combine DENIS and 2MASS data for the J and Ks filters. Published in Astrofizika, Vol. 52, No. 1, pp. 47–62 (Februay 2009).  相似文献   

12.
We present moderate resolution CCD spectra and R photometry for seven KP2001 stars. We revised the spectral classification of the stars in the range λλ4000−8700? . Our photometric data confirmed the behavior of the light curves downloaded from the NSVS (Northern Sky Variability Survey) database. For KP2001-32, presented as a Mira-type variable in NSVS, we estimated absolute bolometric M b and K-band M K magnitudes as well as the distance using the period-luminosity relations. We also estimated the mass loss rate using the calibration relations between mass loss rate and K - [12] index. From the position in infrared color-color diagrams, we confirmed the photometric classification of KP2001-221 as a semiregular variable, based on the light curve of the NSVS database. For the N-type carbon star KP2001-77 we estimated distance and absolute magnitude M K using different calibration methods. For the remaining four objects we derived the absolute magnitudes and distances using our CCD spectra and published JHK S magnitudes. We discuss the nature of these objects on the basis of the obtained results.  相似文献   

13.
We have identified 22 galaxies with photometric redshifts zph=5–7 in the northern and southern Hubble Space Telescope deep fields. An analysis of the images of these objects shows that they are asymmetric and very compact (～1 kpc) structures with high surface brightness and absolute magnitudes of MB≈?20m. The average spectral energy distribution for these galaxies agrees with the distributions for galaxies with active star formation. The star formation rate in galaxies with zph=5–7 was estimated from their luminosity at λ=1500 Å to be ~30 M⊙yr?1. The spatial density of these objects is close to the current spatial density of bright galaxies. All the above properties of the distant galaxies considered are very similar to those of the so-called Lyman break galaxies (LBGs) with z ～ 3–4. The similarity between the objects considered and LBGs suggests that at z ～6, we observe the progenitors of present-day galaxies that form duringmergers of protogalactic objects and that undergo intense starbursts.  相似文献   

14.
ＲＯＳＡＴ卫星的全天巡天观测到了一大批射电星系和各种活动星核,为我们研究这些活动性剧烈的河外天体的辐射机制、多波段辐射相关性以及各类星系核之间的演化联系提供了重要数据。通过将ＲＯＳＡＴ全天巡天观测与ＰＭＮ射电（５ＧＨｚ）巡天观测进行交叉证认,我们得到了６４２颗天射电源。对这些对应体随后进行的光学证认构建了一个星系和活动星系核的大样本。其中３１１个对应体（占５２％）被过去的光学观测证实为河外天体（包  相似文献   

15.
A sixth list of objects from the BIG (Byurakan—IRAS galaxies) sample is given: 87 galaxies identified with 60 point sources from the IRAS Point Source Catalog. The identifications were based on the Digital Sky Survey (DSS), the First Byurakan Survey, blue and red maps from the Palomar Observatory Sky Survey, and infrared fluxes at 12, 25, 60, and 100 µm in the region of +65° +69° and 9h15m 14h00m with an area of 111 deg2. We determined the optical coordinates of the identified galaxies, their departures from the IR coordinates, and their V magnitudes, morphological types, angular sizes, and position angles. The objects have optical magnitudes in the range of 12 m .5-21 m .5 and angular sizes in the range of 2-29. Finder charts from the DSS are given for these objects.  相似文献   

16.
Spectroscopic data are presented for 35 galaxies from selected fields of the Second Byurakan Survey (SBS). The observations were made on the 2.6 m telescope at the BAO using the SCORPIO spectral camera. A majority of the objects were observed for the purpose of improving the classification of types in accordance with an adapted scheme presented in this paper.  相似文献   

17.
A seventh list of objects from the BIG (Byurakan-IRAS galaxies) sample is given: 95 galaxies identified with 63 point sources from the IRAS Point Source Catalog. The identifications were based on the Digital Sky Survey (DSS), the First Byurakan Survey, blue and red maps from the Palomar Observatory Sky Survey, and infrared fluxes at 12, 25, 60, and 100 m in the region of +65° 69° and 14h00m 18h05m with an area of 96 deg2. For the identified galaxies the optical coordinates, their departures from the IR coordinates, the stellar V magnitudes, morphological types, angular sizes, and position angles were determined. The objects have optical magnitudes in the range of 13 m .8-21 m .5 and angular sizes in the range of 4-38. Finder charts from the DSS are given for these objects.  相似文献   

18.
Recent spectroscopic observations of galaxies in the Fornax-Cluster reveal nearly unresolved ‘star-like’ objects with red-shifts appropriate to the Fornax-Cluster. These objects have intrinsic sizes of ≈ 100 pc and absolute B-band magnitudes in the range - 14 < MB < -11.5 mag and lower limits for the central surface brightness μB ≥ 23 mag/arcsec2 (Phillipps et al., 2001, Hilker et al., 1999), and so appear to constitute a new population of ultra-compact dwarf galaxies (UCDs). Such compact dwarfs were predicted to form from the amalgamation of stellar super-clusters (= clusters of star clusters; not to confuse with super stellar clusters (SSC)) by P. Kroupa (1998), which are rich aggregates of young massive star clusters (YMCs) that can form in collisions between gas-rich galaxies. Here we present the evolution of super-clusters in a tidal field. The YMCs merge on a few super-cluster crossing times. Super-clusters that are initially as concentrated and massive as Knot S in the interacting Antennae galaxies (Whitmore et al., 1999) evolve to merger objects that are long-lived and show properties comparable to the newly discovered UCDs. This revised version was published online in September 2006 with corrections to the Cover Date.  相似文献   

19.
The excess number of blue galaxies at faint magnitudes is a subject of much controversy. Recent Hubble Space Telescope results have revealed a plethora of galaxies with peculiar morphologies tentatively identified as the evolving population. We report the results of optical spectroscopy and near-infrared photometry of a sample of faint HST galaxies from the Medium Deep Survey to ascertain the physical properties of the faint morphological populations. We find four principal results. First, the population of objects classified as 'peculiar' are intrinsically luminous in the optical ( M B  ∼ −19). Secondly these systems tend to be strong sources of [O  II ] line luminosity. Thirdly the optical–infrared colours of the faint population (a) confirm the presence of a population of compact   blue galaxies and (b) show the stellar populations of irregular/peculiar galaxies encompass a wide range in age. Finally a surface-brightness comparison with the local galaxy sample of Frei et al. shows that these objects are not of anomalously low surface brightness, rather we find that all morphological classes have evolved to a higher surface brightness at higher redshifts ( z  > 0.3).  相似文献   

20.
The low-dispersion spectra of the First Byurakan Survey and the red and blue images of the Palomar Observatory Sky Survey have been used to identify optically 100 infrared sources from the IRAS Point Source Catalog. The work was carried out over the region 3h 50m ≤ α ≤ 7h 40m and +69° ≤ δ −73° with an area of 75 square degrees. The optical coordinates, their deviations from the infrared coordinates, V magnitudes, color indices, preliminary classes for all the objects, and a number of remarks on interesting objects are presented. Three objects were found to be quasars, 36 are galaxies (including Seyferts and an interacting pair), 5 are faint planetary nebulae, 9 are carbon stars, and 47 are stars of late M subclasses. Translated fromAstrofizika, Vol. 40, No. 1, pp. 5–18, February, 1997.  相似文献   

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