Садржај
Слике
Уплоадјуј своје слике
DSS Images Other Images
Везани чланци
New periodic variables from the Hipparcos epoch photometry
Two selection statistics are used to extract new candidate periodicvariables from the epoch photometry of the Hipparcos catalogue. Theprimary selection criterion is a signal-to-noise ratio. The dependenceof this statistic on the number of observations is calibrated usingabout 30000 randomly permuted Hipparcos data sets. A significance levelof 0.1 per cent is used to extract a first batch of candidate variables.The second criterion requires that the optimal frequency be unaffectedif the data are de-trended by low-order polynomials. We find 2675 newcandidate periodic variables, of which the majority (2082) are from theHipparcos`unsolved' variables. Potential problems with theinterpretation of the data (e.g. aliasing) are discussed.
| Mesures de vitesses radiales. VIII. Accompagnement AU sol DU programme d'observation DU satellite HIPPARCOS
We publish 1879 radial velocities of stars distributed in 105 fields of4^{\circ} \times 4^{\circ}. We continue the PPO series \cite[(Fehrenbachet al. 1987;]{Feh87} \cite[Duflot et al. 1990, 1992 and 1995),]{Du90}using the Fehrenbach objective prism method. Table 1 only available inelectronic form at CDS via to cdsarc.u-strasbg.fr (130.79.128.5) or viahttp://cdsweb.u-strasbg.fr/Abstract.html
| Imaging the host galaxies of high-redshift radio-quiet QSOs
We present new deep K-band and optical images of four radio-quiet QSOsat z approximately = 1 and six radio-quiet QSOs at z approximately =2.5, as well as optical images only of six more at z approximately =2.5. We have examined the images carefully for evidence of extended'fuzz' from any putative QSO host galaxy. None of the z approximately =2.5 QSOs shows any extended emission, and only two of the zapproximately = 1 QSOs show marginal evidence for extended emission. Our3 sigma detection limits in the K images, mK approximately =21 for an isolated source, would correspond approximately to anunevolved Lstar elliptical galaxy at z = 2.5 or 2-3 magfainter than an Lstar elliptical at z = 1, although ourlimits on host galaxy light are weaker than this due to the difficultyof separating galaxy light from QSO light. We simulate simple models ofdisk and elliptical host galaxies, and find that the marginal emissionaround the two z approximately = 1 QSOs can be explained by disks orbulges that are approximately 1-2 mag brighter than an unevolvedLstar galaxy in one case and approximately 1.5-2.5 magbrighter than Lstar in the other. For two other zapproximately = 1 QSOs, we have only upper limits (L approximately =Lstar). The hosts of the high-redshift sample must be nobrighter than about 3 mag above an unevolved Lstar galaxy,and are at least 1 magnitude fainter than the hosts of radio-loud QSOsat the same redshift. If the easily detected K-band light surrounding aprevious sample of otherwise similar but radio-loud QSOs is starlight,then it must evolve on timescales of greater than or approximately equalto 108 yr (e.g., Chambers & Charlot 1990); therefore ournon-detection of host galaxy fuzz around radio-quiet QSOs supports theview that high-redshift radio-quiet and radio-loud QSOs inhabitdifferent host objects, rather than being single types of objects thatturn their radio emission on and off over short timescales. This isconsistent with the general trend at low redshifts that radio-loud QSOsare found in giant elliptical galaxies while radio-quiet QSOs are foundin less luminous disk galaxies. It also suggests that the processesresponsible for the spectacular properties of radio-loud AGNs at highredshifts might not be generally relevent to the (far more numerous)radio-quiet population.
| Selection of standard stars for photometric observations with the 91-cm reflector at Okayama
Not Available
| MK classification and photometry of stars used for time and latitude observations at Mizusawa and Washington
MK spectral classifications are given for 591 stars which are used fortime and latitude observations at Mizusawa and Washington. Theclassifications in the MK system were made by slit spectrograms ofdispersion 73 A/mm at H-gamma which were taken with the 91 cm reflectorat the Okayama Astrophysical Observatory. Photometric observations in UBV were made with the 1-meter reflector at the Flagstaff Station of U.S.Naval Observatory. The spectrum of HD 139216 was found to show a strongabsorption line of H-beta. The following new Am stars were found:HD9550, 25271, 32784, 57245, 71494, and 219109. The following new Apstars were found: HD6116, 143806, 166894, 185171, and 209260. The threestars, HD80492, 116204, and 211376, were found to show the emission inCaII H and K lines.
| A UV image of M31
A UV(2000 A) picture of the Andromeda galaxy (M31) was obtained from aballoon-borne experiment. In addition to the central region of thegalaxy, the general spiral structure is seen as a ring which coincideswith the distribution of the OB associations and H II regions. Theelliptical companion NGC 205 is also barely detected. The fluxes of thisgalaxy NGC 205 and of NGC 206, a bright association in the spiralstructure of M31, are found compatible with their known stellar content.For the central part of M31, the flux is in agreement with previousdeterminations. Detailed analysis confirms the diffuse aspect of thiscentral region and reveals a well peaked luminosity distribution.Possible origins for the central UV radiation are also discussed.
| UBV Photoelectric Photometry of 259 PZT Stars
Abstract image available at:http://adsabs.harvard.edu/cgi-bin/nph-bib_query?1980PASP...92..215G&db_key=AST
| Rocket ultraviolet imagery of the Andromeda galaxy
Far-UV electrographic imagery of M31 is presented which was obtainedduring a sounding-rocket flight with an electrographic Schmidt camerasensitive in the wavelength range from 1230 to 2000 A. The resolution inthe imagery is such that 50% of the energy from a point source isconfined within a circle 40 arcsec in radius. Two conspicuous featuresare observed in the UV image of M31: one corresponding to a brightassociation (NGC 206) in the SW region of the disk and one centered onthe galactic nucleus. Indications of the general spiral-arm structureare also evident. Absolute photometry and brightness distributions areobtained for the observed features, and both the central region and NGC206 are shown to be diffuse sources. It is found that the brightnessdistribution of the central region is a flat ellipse with its major axisclosely aligned with the major axis of the galaxy, which favors a sourcemodel consisting of young early-type stars close to the galactic planeand constitutes strong evidence against a nonthermal point source at thegalactic center.
| Die Intensitäts-und Farbverteilung in Andromeda-Nebel. Mit 17 Textabbildungen
Not Available
|
Додај нови чланак
Линкови у сродству са темом
Додај нови линк
Чланови следећих група \:
|
Посматрања и Астрометриски подаци
| Сазвежђа: | Андромеда |
| Ректацензија: | 00h41m51.22s |
| Deклинација: | +38°53'46.7" |
| Apparent магнитуда: | 7.625 |
| Даљина: | 349.65 parsecs |
| Proper motion RA: | 9.9 |
| Proper motion Dec: | -7.1 |
| B-T magnitude: | 7.576 |
| V-T magnitude: | 7.621 |
Каталог и designations:
|
