... Astrometry with the FGS, by contrast, proceeds in the reverse order; the positions of the individual objects are found first, and then a virtual plate is constructed with the help of data from the guide stars and check stars. ... Corrections based on guide star data are referred to as POSITION mode dejittering , and those based on check star data are called drift corrections . ... The adjustments to the astrometry centroids from this POSITION mode dejittering correction are typically about 1 mas. ...

Next: Radial velocity of the Up: Optical spectrum of IRAS04296 Previous: Observations and spectra reduction . ... However, molecular emission features are only very rarely observed in the optical spectra of PPNe. ... On the other hand, it is well known that cometary nuclei spectra show prominent Swan band emission. In both spectra of IRAS04296 we have discovered strong emission in the (0;0) and (0;1) bands of the Swan system of the molecule. ... Now consider the case of IRAS04296. ...

... In Fig. 2 the spectrum of the host galaxy HS1035+4758 is shown, in which typical HII-galaxy narrow emission lines are seen: H 4861, [OIII] 4959,5007, H 6562, [NII] 6548,6584 and [SII] 6716,6731 ?. ... The spectral evolution of SN 1998bv is illustrated in Fig. ... The change of the spectrum between April 6 and 19 with clear reddening shortward of H during these 2 weeks indicates seemingly that the 1st spectrum was observed in the period between the 20th and 30th days after the peak of the light curve...

... Subject and Problems of Stellar Astronomy. ... Plane of Galaxy, Methods of Its Location Determination. ... Stars Distances. ... Other Methods of Stars Distances Determination. ... Tangential Velocities, Their Determination by Self-Motions. ... Determination of Solar Apex and Spatial Velocity by Radial and Spatial Velocities of Stars. ... Features of Orientation and Parameters of Peculiar Stellar Velocities Ellipsoid. ... General and Selective Light Absorption in Galaxy. ... Darc Clouds in Galaxy. ...

... Absorption by neutral atomic hydrogen in luminous spiral galaxies provides an excellent tool to study the gas kinematics in their nuclear regions. ... Since the absorption lines are intrinsically narrow as a result of the low temperatures of the optically thick gas, typically 30 to 150 K (Dickey, Salpeter & Terzian 1979), it is surprising that numerous galaxies show H I absorption over a broad range of velocities (a few hundred kms -1 ); see e.g., Fig. ... range . ... NGC 253 . ... NGC 660 . ...

Next: Identifications and Efficiency Up: THE DEEP X-RAY RADIO Previous: Source Classification . ... For some sources which did not have NVSS positions before the time of optical observations, arcsecond positions from the Texas survey (Douglas et al. 1996) and NED (typically based on VLA data) were used. ... All X-ray/radio sources without counterparts on the survey plates were imaged at either the KPNO 0.9m or the CTIO 0.9m telescopes. ... Previously Identified Sources . Sample Properties . ...

... A universal physical relation for quasars . ... Harvey Tananbaum and his collaborators have first observed a relation between the soft X-ray and the optical/ultraviolet emission in AGN in 1979. Such relation is nonlinear, and it is usually parameterized as dependence between the logarithm of the monochromatic luminosities at 2500 †Е ( L 2500†Е ) and 2 keV ( L 2keV ) . ... Yet, the dispersion along the L 2500†Е тАУ L 2keV relationship is found to be rather high, typically ~0.35тАУ0.4 in log units. ...

... Up: Data Analysis and Processing Techniques . ... Also, a method for quality control of CCD observations is suggested. ... Everyone who observes a celestial object using a CCD detects moving celestial objects as a ``by product''. ... We hope that our investigations may be useful for near-Earth space control and also for searches of the moving celestial objects through analysis of old and new CCD frames obtained at any amateur or professional astronomical observatory. ...

... We are using Canadian Galactic Plane Survey l 74.2њ, -3.6њ < b This poster gives preliminary results for a full-fledged analysis of the gas properties and distribution of HISA features in the CGPS. ... where T ON and T OFF are observed brightnesses on and off the HISA feature, T S is the spin or excitation temperature of the HISA gas, tau is its optical depth, T C is the continuum intensity, and p is the fraction of H I emission lying behind the HISA feature. ... GIF | ...

We present broadband photometry in the optical, near infrared and sub-millimetre, and mid-infrared spectrophotometry of a selection of carbon stars with optically thin envelopes. ... Beside the emission features at 11.3 \mu m due to silicon carbide grains in the circumstellar environment, many of our mid-infrared spectra show an emission feature at 8.6 \mu m. All the observed spectral energy distributions exhibit a very large far-infrared flux excess. ...

... Laboratory and theoretical modelling of the UV bump on the interstellar extinction curve is a very popular topic in dusty investigations. ... feature is illustrated by Fig. 10 where the profiles were calculated using the model of graphite spheres. Figure 10: Normalized extinction efficiencies for graphite spheres. ... The lower panel shows the summary extinction of two graphite spheres with radii and (from upper panel) taken in equal proportions. ...

SWIRL DISTRIBUTION ON THE LUNAR SURFACE: LOCATIONS ANTIPODAL TO THE YOUNG BASINS? ... There are two main classes of hypothesises of the swirl origin: formation of the swirls in the regions antipodal to large impact basins (1), and formation of the swirls in result of cometary impacts (2). ... The Orientale basin is youngest. ... Fig. ... On the other hand, there are two cases of absence of correlation between swirl areas and regions antipodal to impact basins (for small swirl formations). ...

Next: Star Formation Rate and Up: No Title Previous: Calculation of Evolutionary Tracks . To start calculations, we choose the distributions of the initial binary parameters: the mass of the primary ZAMS component, , binary mass ratio, , orbital separation a . ... whereas the mass ratio distribution is not. ... The zero assumption often made is that the mass ratio distribution has a flat shape, that is binaries with a high mass ratio occur as frequently as those with equal masses. ...

... arXiv.org . ... Here we present and analyse the properties of an updated sample of 37 ULP Cepheids observed in galaxies within a very large metallicity range of 12+log(O/H) from ~7.2 to 9.2 dex. ... The Origin of Color Gradients in Early-Type Systems and Their Compactness at High-z . ... Multiwavelength Observations of Markarian 421 in 2005 - 2006 . ... In addition to this, the well-sampled spectral energy distribution of Markarian 421 (1101+384) is presented for three different activity levels. ...

spaceweb@oulu.fi - last update: 20 September 1998, 2020 UT (RR) . Traveling Convection Vortex (TCV) is a name given to a specific type of daytime magnetic impulsive events observed by high-latitude ground-based magnetometer arrays. Since the most likely source for TCVs is the solar wind , they are considered to be important processes in transfering energy from the solar wind into the magnetosphere . ... For example, one AMPTE Lithium release in the solar wind caused a TCV event . ...

The large magnetic cloud caused by coronal mass ejection at the Sun on January 6, 1997 came to the Earth at early morning on January 10 and continue to interact with Earth's magnetosphere till January 11 (see for example home page of this event prepeared by Dr. M.Peredo http://www-istp.gsfc.nasa.gov/istp/cloud_jan97/event.html ). ... During the days discussed here INTERBALL-1 satellite was in the magnetosphere (MS) near its dusk flunk - see the Fig. 1 for compearing. ...

The radial distribution of metallicity of star-forming galaxies in a galaxy cluster can inform us about the mass assembly and enrichment history of the galaxy cluster. ... Both galaxy clusters are cool-core clusters at redshift z т?? ... The gas-phase metallicity of star- forming galaxies in MACS1115+01 exhibit anti-correlation with projected distance т??0.15 ТБ 0.08 dex/Mpc, whereas the radial metallicity distribution of RXJ1532+30 is statistically flat (т??0.09 ТБ 0.12 dex/Mpc). ...

Contents. planet: 5 - Jupiter satellites: J1 - Io : 10, J3 - Ganymede : 15, J4 - Callisto : 6 total number: 31 type: relative dates: 1997-1997 observatory: see observatories list in the relevant article. ... Emelianov N. V., Vashkovjak S. N. (2009) Astrometric results of the observations of the mutual occultations and eclipses of the Galilean satellites of Jupiter in 1997. ... Position angle A in degrees (topocentric for mutual occultation or heliocentric for mutual eclipse) 10. ...

... Mindful of these biases, I can now explore the relations between the measured rotation periods and various other observables. The hypothesis behind monitoring stellar variability is that active stars have asymmetric spot distributions on their photospheres. ... They found that only stars with rotation periods greater than seven days show variations greater than 0.4 magnitudes at I. Bouvier et al . ... 1993a) demonstrated a relation between X--ray flux and spectral type in ZAMS stars. ...

XMM-Newton CCF Release Note XMM-CCF-REL-183 EPIC-pn spectral response R. D. Saxton 11 November 2004 1 CCF components Name of CCF VALDATE Blocks changed XSCS ag EPN QUANTUMEF 0015.CCF 2000-01-01 FRACTION CHANNEL, FRACTION ENERGY QE TOTAL, EBINS FRACTION NO EPN REDIST 0009.CCF 2000-01-01 NOISE PARAMS, PARTEVENT PARAMS THRESH LOSS NO 2 Changes Recent calibration work has shown that the Epic-pn redistribution function is in practice narrower than that represented in the current matrices. ...