... We will consider the rms, (K), for observations with a receiver of system temperature, T , frequency resolution, per polarization, and total integration time per observing cycle, . ... For ``in-band'' frequency switching, the line under investigation is always in the observing band. ... Position Switching or ``Out-of-Band'' Frequency Switching: Here the line is only observed for one half of the time, with noise being present all of the time. ...

We present a database of UV-to-FIR data of 83 nearby starburst galaxies. ... The NIR data are from new observations obtained at the NASA/IRTF and the Mount Laguna Observatory, combined with the published results from observations at the Kitt Peak National Observatory. ... In conjunction with IRAS and ISO FIR flux densities, all these data form a set of observed spectral energy distributions (SEDs) of the nuclear regions of nearby starburst galaxies. ...

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. ...

We explore the idea that the occurrence of nano-flares in the magnetic loop around the O VI formation temperature could explain the observed red-shift of mid-low transition region lines as well as the blue-shift observed in low coronal lines (T > 6 10^{5} K). Observations are compared to numerical simulations of the response of the solar atmosphere to an energy perturbation of 4 10^24 ergs representing an energy release during magnetic reconnection in a 1-D semi-circular flux tube. ...

Next: The Newton--Raphson Method. Up: Fitting of Data Previous: Fitting of Data . ... In a linear problem, if the errors on the observations have a gaussian distribution, the ``Maximum Likelihood Principle'' gives you the ``best estimate'' of the parameters as the solution of the so-called ``Least Squares Minimization'' that follows: . ... A certain number of numerical methods have been developed to solve the non--linear least squares problem, four have so far been implemented in MIDAS. ...

One of the first light images taken on April 22, 1998 in 195 Angstroms . Loops viewed on April 25, 1998, seen in 171 Angstroms. ... Active Region seen on April 26, 1998 in 171 Angstroms . ... Flare observed in 1216 Angstroms on May 19, 1998 . ... Post flare loop observations on August 16, 1998 observed in 171 Angstroms . Post flare loop observations on August 16, 1998 observed in 195 Angstroms . ... Active regions observed on August 19, 1998 in 171 Angstroms . ...

Magda Arnaboldi (MSSSO), Tom Oosterloo (ATNF), Francoise Combes (DEMIRM), . ... New, high resolution observations of the H I emission line and 20-cm continuum at the Australia Telescope Compact Array (ATCA) for the prototype polar ring galaxy NGC 4650A are presented. ... Keywords. galaxies: individual (NGC 4650A) - galaxies: dynamics - galaxies: dark matter. related paper: Combes Arnaboldi 1996, A 305, 763, . The dark halo of polar-ring galaxy NGC 4650a: flattened towards the polar ring ?'' . ...

... Back to the Live Radiation Monitor Data The radiation monitor on board XMM-Newton registers the total count rate and basic spectral information on the background radiation impinging on the spacecraft and its scientific instruments. ... Counting of pulses for a selected energy band and above the low thresholds. ... Sensitivity: due to the electronic threshold, actually only electrons with energy greater than 130 keV and protons greater than 1.3 MeV can be measured by this unit. ...

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. ...

Next: NICMOS/HST H-band (F160W) Images Up: NICMOS Science Previous: HST NICMOS Observations of . ... Observations of P . ... The NICMOS team has devised a comprehensive program of observations of the Galactic Center. ... Data in hand give a first look at variability and a detailed look at the search for the tip of the main sequence will be discussed where NICMOS has demonstrated adequate sensitivity and photometric precision to identify likely O8-B1 stars at the Galactic Center. ...

... At high latitudes, the E-region auroral electrojets and field-aligned currents produce 'radar aurora' that are somewhat more complicated than the equatorial radar echoes. ... Type 4 echoes are a special type of two-stream events associated with anomalous electron heating by the auroral electrojet waves. ... Res. ... Hedberg, and J. A. Nordling, Observations of auroral E-region plasma waves and electron heating with EISCAT and a VHF radar interferometer, J. atmos. terr. ... Observations, J. Geophys. ...

CORONAL METALLICITIES OF ACTIVE BINARIES Vinay Kashyap, Jeremy Drake, Deron Pease Harvard­Smithsonian Center for Astrophysics JЁ urgen Schmitt Max Planck Institut fЁ ur Extraterrestriche Physik SUMMARY We analyze EUV and X­ray data on a sample of X­ray active binary stars (HR 1099, – And, UX Ari, VY Ari, ё UMa, 44i Boo, and YY Gem) to determine coronal abundances. EUVE spectrometer data are used to obtain line fluxes, which are then used to determine Differential Emission Measures (DEMs). ...

... Fitting the observed dependence includes calculations of the polarization cross-sections averaged over particles orientation and size distribution, their normalization and the comparison of obtained dependencies with Serkowski's curve representing observational data for a chosen star. ... Variations of the polarization factors with wavelength are shown in Fig. 16 for homogeneous spheroidal particles with PF orientation. ... The distinction between prolate and oblate spheroids is also clearly seen. ...

... Science Users Information > Observing with ESO Telescopes > Phase 2 Preparation > Observing conditions . ... Service Mode Philosophy . ... The following definitions of the observing conditions are common between Phase 1 preparation and Phase 2 preparation, as well as between Service Mode and Visitor Mode observations. ... Seeing (Phase 1) and Image quality (Phase2) constraints . ... Please note that observing conditions requested at Phase 2 should match those at Phase 1 (see Service Mode Policies). ...

Irregular phenomena in the Earth Pole oscillation process and temporal variations of geopotential Valery Bondarenko, Vadim Perepelkin s The observed irregular phenomena in the Earth Pole oscillation process are very variety. ... These phenomena indicated in the IERS data are the "abnormal" fluctuation of the Earth Pole coordinates which owing to changing of the geodynamical parameters gives negative result in interpolation and forecast of the first approximation mathematical model. ... Fig. ...

It is possible to piece together the processes that have shaped the observed characteristics of a galaxy by studying its stars in detail. The Large Magellanic Cloud (LMC) is an excellent candidate for this type of study because of its favourable viewing angle and ongoing star formation. I present the results of high-resolution VLT/FLAMES observations of ~80 red giant stars around star cluster NGC 1846, located in the disc of the LMC. ...

This illustration shows the disk of our Milky Way Galaxy surrounded by a fain, extended halo of old stars. Astronomers using the Hubble Space Telescope to observe the nearby Andromeda Galaxy serendipitously identified a dozen foreground stars in the Milky Way halo. They measured the first sideways motions (represented by the arrows) for such distant halo stars. The motions indicate the possible presence of a shell in the halo, which may have formed from the accretion of a dwarf galaxy. ...

... For each observed position the table contains designation of object as in file of observations, the time of observation, the number and name/ preliminary designation of minor planet supposedly identical with observed object, the values of O – C (observed position minus computed one) in right ascension and declination expressed in arcsec, the difference O – C between observed magnitude and computed one, the code of observatory in the Observatory list (see Observatories section). ...

... In order to compare the number of different evolutionary stages obtained and X-ray luminosity of the chosen X-ray sources with the observed galactic values we use the sum of C/O+O/C , where C and O are the calculated and observed values of a given binary type, respectively. If we make comparison for a number of different binary species (for example, we compare the number of CV, number of X-ray pulsars,   total X-ray luminosity of LMXB, etc.), we write this criterion in the form: . ...