首页 | 本学科首页   官方微博 | 高级检索  
相似文献
 共查询到20条相似文献，搜索用时 31 毫秒
1.
We report observations of 24 stars in the fields of the three Seyfert galaxies MCG +08-23-067, Mrk 817, and Mrk 290. The observations were made with a CCD array photometer in the BVRcIc bands. The V magnitudes of the observed stars ranged from 13.5 and 17.2. For stars of approximate magnitude 15, the typical photometric errors are 0.010, 0.011, 0.008 and 0.011 magnitude in the BVRI bands, respectively. The BVRI magnitudes of all these stars were not known previously. In the field of the galaxy Mrk 290 a star has been found that probably has a periodic brightness variation with P=1.518 days and the mean value V=14.80 and which may belong to the class of “spotted” stars. 14′x14′ charts are supplied for identifying the stars. These results can be used for differential photometry of active galactic nuclei in the BVRI bands. __________ Translated from Astrofizika, Vol. 51, No. 1, pp. 41–50 (February 2008).  相似文献   

2.
Results are presented from CCD BVRI observations of comparison stars in the neighborhoods of 22 galaxies with active nuclei having right ascensions ranging from 0 to 12 hours, of which 19 are Seyfert galaxies. The observed stars have magnitudes ranging from V=11 to V=17. For stars brighter than V=14 the typical photometic error is 0.01m. The B, V, Rc, and Ic magnitudes of most of these stars were not known previously. 14′×14′ finding charts are included. These results can be used for differential photometry of the AGNs in the B, V, Rc, and Ic bands.__________Translated from Astrofizika, Vol. 48, No. 2, pp. 191–211 (May 2005).  相似文献   

3.
Results are presented from CCD BVRI-observations of 145 comparison stars in the neighborhoods of 14 Seyfert galaxies, 3 quasars, and 5 BL Lac objects with right ascensions of 12 to 24 hours. The magnitudes of the observed stars ranged from V=11 to V=17. The typical photometric error for stars brighter V=14 is 0m.01. The B, V, Rc, and Ic magnitudes of most of these stars were not known previously. 14′ x 14′ finding charts are provided. These results can be used for differential photometry of the nuclei of active galaxies in the B, V, Rc, and Ic bands.__________Translated from Astrofizika, Vol. 48, No. 3, pp. 365–379 (August 2005).  相似文献   

4.
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   

5.
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   

6.
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   

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.
Formation paradigms for massive galaxies have long centered around two antipodal hypotheses – the monolithic-collapse and the accretion/merger scenarios. Empirical data on the stellar contents of galaxy halos is crucial in order to develop galaxy formation and assembly scenarios which have their root in observations, rather than in numerical simulations. The Hubble Space Telescope (HST) has enabled us to study directly individual stars in the nearby E/S0 galaxies Cen A, NGC 3115, NGC 5102, and NGC 404. We here present and discuss HST single-star photometry in V and I bands. Using color-magnitude diagrams and stellar luminosity functions, we gauge the galaxies' stellar contents. This can be done at more than one position in the halo, but data with deeper limiting magnitudes are desired to quantify the variation of metallicity with galactocentric radius. We here compare the color distributions of red giant stars with stellar isochrones, and we intercompare the galaxies' halo populations, noting that their total absolute V magnitudes cover the range from about –21.5 to –17.5. In the future, we plan to model the stellar metallicity distributions with the aim to constrain chemical enrichment scenarios, a step towards unravelling the evolutionary history of elliptical and lenticular galaxies. This revised version was published online in August 2006 with corrections to the Cover Date.  相似文献   

9.
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   

10.
A fourth list of point sources from the IRAS Point Source Catalog (PSC) that are optically identified with stars of late spectral types is given. The list contains data on 41 objects. The identifications were based on the Digital Sky Survey (DSS), the First Byurakan Survey, blue and red maps of the Palomar Observatory Sky Survey, and infrared fluxes at the wavelengths 12, 25, 60, and 100 μm in the region of +65° ≤ δ ≤ +69° and 05h10m ≤ α ≤ 18h10m. Of the 41 objects, which are given in the IRAS PSC as unidentified sources of infrared emission, 9 are associated with known stars in existing catalogs while 32 sources remained unidentified in the optical range, one of which is also a source in the deep IRAS survey (IRAS Serendipitous Source Catalog). The optical coordinates, their departures from the IR coordinates, the V stellar magnitudes, the color indices CI, and the preliminary spectral subtypes have been determined. The objects have optical magnitudes in the range of 8m.5-14m.5. Finder charts from the DSS are given for 32 of the objects. Translated from Astrofizika, Vol. 43, No. 3, pp. 361-368, July–September, 2000.  相似文献   

11.
A catalogue of photoelectric stellar magnitudes and colours in the UBVR Johnson system in 47 sky areas with galaxies near the Main Galactic Meridian is presented. The catalogue includes 1141 stars within the V magnitude interval 4m.5–15m.5. The rms errors are ±0.014, ±0.026, ±0.012, ±0.016 mag for stellar magnitudes V and colours (U – B),(B – V),(V – R), respectively. The catalogue contains accurate equatorial coordinates (α, δ)1950.0, too.  相似文献   

12.
The absolute proper motions of about 275 million stars from the Kharkov XPM catalog have been obtained by comparing their positions in the 2MASS and USNO-A2.0 catalogs with an epoch difference of about 45 yr for northern-hemisphere stars and about 17 yr for southern-hemisphere stars. The zero point of the system of absolute proper motions has been determined using 1.45 million galaxies. The equatorial components of the residual rotation vector of the ICRS/UCAC2 coordinate system relative to the system of extragalactic sources have been determined by comparing the XPM and UCAC2 stellar proper motions: ω x,y,z = (−0.06, 0.17, −0.84) ± (0.15, 0.14, 0.14) mas yr−1. These parameters have been calculated using about 1 million faintest UCAC2 stars with magnitudes R UCAC2 > 16 m and J > 14 m . 7, for which the color and magnitude equation effects are negligible.  相似文献   

13.
Part five of optically identified point sources from the IRAS Point Source Catalog (PSC) contains data on 19 late-type stars. The identifications were based on the Digitized Sky Survey (DSS), the First Byurakan Survey (FBS), blue and red maps of the Palomar survey (POSS), and infrared fluxes at 12, 25, 60, and 100 mm in the region of +61° ≤ δ ≤ +65° and 05 h 30 m ≤ α ≤ 18 h 35 m with an area of 357 sq. deg. Of the 76 objects given in the IRAS PSC as unidentified sources of infrared radiation, 51 are associated with known stars in existing catalogs, 6 are objects from the FBS of late-type stars, and 19 sources remained unknown in the optical range. For the identified stars we determined the optical coordinates, their departures from the IR coordinates, the Vstellar magnitudes, the color indices CI,and the preliminary spectral subtypes. The objects have optical magnitudes in the range of 8 m −16 m .Gas-dust shells are assumed to exist around four of the sources. Finder charts from the DSS are given for 19 of the objects. Translated from Astrofizika, Vol. 42, No. 1, pp. 53–59, January–March, 1999.  相似文献   

14.
A Microtek ScanMaker 9800XL TMA was used to scan 102 plates of 60° declination zone of the northern sky. The images were obtained within the scope of the FON project using the double wide-angle astrograph of the Main Astronomical Observatory (National Academy of Sciences of Ukraine). The procedure is described of processing these scans and compilation of the catalog of equatorial coordinates and brightness. Mean square errors of positions and B-magnitudes of 1 108 603 stars of the output catalog (in the range from 56 to 64° in declination and from 0 to 24 h in right ascension) largely depend on the position on the plate, multiplicity of overlapping, and stellar magnitude. The standard deviations are 0.10–0.32″ for coordinates and 0.04–16 m for stellar magnitudes. The average values of mean square deviations of data of the obtained catalog from data of PPMX and UCAC catalogs are 0.23″ and 0.18 m .  相似文献   

15.
The characteristics of gravitational bursts from active galactic nuclei, and globular clusters are obtained for three astrophysical situations:(i) scattering of stars by massive black holes residued at the centers of galaxies and globular clusters; (ii) the close encounters of stars in the nuclear regions of these objects; (iii) scattering of stars by black holes of stellar mass containing in the stellar population of galactic nuclei and clusters. The most effective source of gravitational bursts appears to be a scattering of stars by the massive central black holes which produces the bursts with dimensionless amplitudeh10–19–10–21 and frequencies from 10–1 to 10–5 Hz. The characteristics obtained correspond to the possiblities of a future gravitational-wave experiment with use of laser Doppler tracking of interplanetary spacecrafts.  相似文献   

16.
Certain characteristics of quasars observed in the regions of three rich clusters of galaxies are investigated. It is shown that the luminosity functions constructed for samples of quasars from the regions of the Virgo and Fornax clusters are similar to each other and show a very sharp maximum at a stellar magnitude of 18m.0-18m.3. The maximum of the luminosity function for quasars from the region of the Coma cluster (A 1656) is shifted toward fainter magnitudes and lies at 21m. This effect is explained by the affiliation of the majority of the quasars to the respective clusters. It is shown that the absolute stellar magnitude of these quasars is –13m, which corresponds to the luminosity of dwarf galaxies of low luminosity. It is suggested that the local quasars are formed in two ways: by ejection from galactic nuclei and in quasar associations without a parent galaxy, directly from protostellar matter.  相似文献   

17.
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   

18.
BIMA SONG is a systematic imaging study of the 3 mm CO J = 1 → 0molecular emission within the centres and discs of 44 nearby spiral galaxies on size scales of a few hundred parsecs (6-9"). The overall goal of the survey is to study the role of molecular gas in the evolution of spiral galaxies. To this end, BIMA SONG addresses 1) the distribution and physical conditions of the molecular gas in galactic discs and its relation to star formation, 2) the effects of a stellar bar on the kinematics of molecular gas, including the possible inflow of gas along a bar, and 3) the distribution and role of molecular gas in the central few hundred parsecs of active and quiescent galaxies. The source list includes all (except M33and M31) 44 galaxies of Hubble types Sa–Sd, with declinations δ >−20°, visual magnitudes B < 11.0, velocities v hel <2000 km s-1, and inclinations i < 70°. Beyond the specific scientific questions we will address, this survey will provide a unique database for astronomers who study galaxies at all wavelengths. This revised version was published online in July 2006 with corrections to the Cover Date.  相似文献   

19.
A 10th list of late-type M and C stars found on plates of the First Byurakan Spectral Sky Survey in the − 11° ≤ δ ≤ − 7° belt with an area of about 1070 deg2 is given. The list contains data on 169 red stars, 117 of which were found for the first time: 8 are new C stars, 3 are Cstar candidates, 104 are M stars, 1 is either an M or an S star, and 1 object on the survey plate cannot be classified. Of the 117 objects, 47 are unidentified IRAS sources. A statistical analysis of the objects that are and are not identified with IRAS sources shows that the identified stars are, with a high probability, brighter and have relatively more massive envelopes. Two stars were found to have fairly large brightness variability (with an amplitude of at least 6m.O). Gasdust shells are assumed to exist around nine of the IRAS sources. The equatorial coordinates, spectral types, and stellar magnitudes, determined on Palomar E maps, are given for the selected objects. Translated from Astrofizika, Vol. 41. No. 4, pp. 545–559, October–December, 1998.  相似文献   

20.
We performed a series of CCD observations in BVRI bands of a celestial region in cluster M67 (NGC 2682) to study the photometric system of the Kyiv network telescope. The signal recording system consists of a CGE-1400 telescope, Celestron #94175 focal reducer, an automatic turret with a set of UBVRI filters, and a Rolera Mgi CCD camera. The operating field of the system is 10.62′ × 10.62′. CCD images are processed in the MIDAS/ROMAFOT package. The reduction coefficients of the instrumental photometric system relative to Johnson’s BVRI system are determined. The resulted value of the module of distance to cluster M67 V ? M V = 9.63 m does not contradict the results of other researchers. The mean square errors for one determination of stellar magnitude for different bands are 0.02–0.12 m . The errors in determining equatorial coordinates in the TYCHO-2 catalog system are ± 1″.  相似文献   

设为首页 | 免责声明 | 关于勤云 | 加入收藏

Copyright©北京勤云科技发展有限公司  京ICP备09084417号