spaceweb@oulu.fi - last update: 1 July 1998, 1200 UT (RR) . ... Relates the wave number k to the wave frequency. ... From the equation of motion , m d v /dt = q( v x B ) one can calculate that, in a presence of magnetic field B , a charged particle is accelerated in direction perpendicular to both v (perp) and B . ... The angle a between magnetic field B and velocity vector of a charged particle, v ., i.e., sin a = v(perp) / v(total), where v(perp) refers to the velocity component perpendicular to B . ...

Next: Bivariate polynomial interpolation Up: Echelle Spectra Previous: Removal of particle . The estimation of the background is one of the critical points in the reduction of echelle spectra for two reasons. ... diffuse light in the interorder space coming from adjacent orders. sky background spectrum . ... These locations are defined when performing the order definition (command DEFINE/ECHELLE or DEFINE/HOUGH ) and can be displayed by command LOAD/ECHELLE . ... Sky background definition . ...

... The FOC suffers from various types of background, the most important of which are thermal electrons, Cerenkov radiation from high energy particles, geocoronal emission lines, zodiacal light, and light scattered within HST from the bright Earth or Moon. ... From on-orbit measurements using the f /96 camera, the former background has been found to vary with solar zenith distance (ZD); see Sections 6.4, 6.5, and 7.0 of the FOC Instrument Handbook , version 7.0, for more details. ...

... Energy . ... The free ions and electrons in a plasma behave the same way. Knowing the temperature of the high atmosphere of Earth, or that of the Sun, we can calculate energies expected of ions and electrons found there. However, ions and electrons actually observed in space are often much, much more energetic, and may move at a respectable fraction of the velocity of light (300,000 km/sec or 186,000 miles/sec). ... Typical energy of an electron in the polar aurora. 40,000 ev . ... 50,000 ev . ...

... The first task assumes the searching for chemical composition and sizes of particles which give the wavelength dependence of the extinction efficiencies close to the observed dependence of . Figure 7: Wavelength dependence of the extinction efficiency factors for homogeneous spherical particles of different sizes consisting of astronomical silicate and amorphous carbon. The dashed segment shows the approximate wavelength dependence of the mean galactic extinction curve at optical wavelengths. ...

Next: Displaying Images Up: Spectral Line Data Reduction Previous: Computation . A few comments are in order when using the imaging task, invert , to create spectral cubes (more information on invert can be found in Chapter 13 ): . To conserve space, invert produces a single beam dataset for all planes of a cube. ... That is, invert usually insists that no channels of a spectrum are flagged before that spectrum can be used for imaging. ... The slop keyword takes two values. ... VELSW . ...

So the evidence for Dark Matter is fairly overwhelming. ... Theory: if the Universe is closed then all the luminous matter seen in galaxies contributes only 0.5% of the mass required to eventually halt the expansion . ... This means that galaxies are surrounded by dark matter halos which trapped baryonic gas (e.g. hydrogen) and turned it into stars. ... WIMPS - weakly interacting massive particles created in the extremely early universe . ... Theory 99% of the Universe is Dark Matter . ...

... The group of radio emitting X-ray binaries (XRB's), such as SS433, Cyg X-3, LSI , Cir X-1, etc., exhibit highly variable bursting radio emission interpreted as synchrotron radiation from relativistic electrons. ... In this paper, a numerical model for radio outbursts in XRB's is developed. The model is based on a process of continuous injection of relativistic particles into a spherical expanding plasmon, ejected following a transitory supercritical accretion event onto the compact star. ...

Chair of solid state physics . ... One-particle Green’s function (Non interacting fermions) . Verbal definition of retarded one-particle Green’s function. ... One-particle Green’s function (Interacting fermions) . Formal definition of one-particle Green’s function. ... Quasi particles in Hartree-Fock approximation. ... Quasi particles and one-particle Green’s function. ... Vertex function and scattering of quasi particles. ... Matsubara Green’s function foe free particles. ...

... The spatially resolved structure near the hydrogen emission H line was found in the spectrum taken with the BTA/SCORPIO in June, 2013. ... The fragment of the Nova V1494 Aql spectrum is shown in Fig.1. ... The Nova V1494 Aql has passed the stage of the supersoft X-ray source (SSS) in the period between 218 and 516 days after the visible light maximum (Schwarz et al., ... The spectrum of Nova V1494 Aql taken on 2013 June 9 with BTA/SCORPIO . ... The vertical lines are the lines of night sky emission....

... Bad Astronomy . ... Mad Science . ... Keep Bad Astronomy close to your heart, and help make me filthy rich. ... I read in your archives that: "The black hole will slowly radiate away?. ... Since this represents energy leaving the black hole, it will slowly release all of its mass in this fashion." ... If a pair of particles is produced which gets its rest mass energy from the gravitational field of the hole, and one particle is lost, then there will be a decrease in the energy of the hole. ...

... Program of the Course of Radio Astronomy . Moscow State University , Physics Department , Astronomy Division , 4 th year, 60 hours in total) . ... Molecular maser emission. ... The emission of the interstellar neutral hydrogen. ... Pacholczyk, A. G. Radio Astrophysics, W. H. Freeman & Co., ... Frontiers of Astrophysics, Avrett, E. H., ed., Harvard University Press, Cambridge, Mass., ... Kaplan, S. A., Pikelner, S. B. The Interstellar Medium, Harvard University Press, Cambridge, Mass., ...

... spectrum . ... nsource <n> : choice of source function (def: 3=Feautrier) . noptype <n> : choice of continuous opacity (def: 1=Kiel) . nhedat <nhedat> : choice of HeI data (BCS or Mon treal) (def: 1=BCS) . ... read_model <filename>: read model atmosphere in QUB/STERNE2 format . ... wavmax <w_max> : distance from line centre to compute . ... nvturb <n vt > : number of points in -dependent v turb . ... tau_exp <n> : increase resolution of optical depth scale by adding additional points . ...

... X-rays are made up of photons that are emitted from stars, or quasars, or supernovae, the sun, or simply: anything that is undergoing a change either in size or temperature or giving out heat. ... in an X-ray binary star system, in which one normal star's orbit is crossed by a neutron star, when the neutron star by means of gravitational pull takes matter from the normal star X-rays form. ... Artists conception of a normal star (HDE 226868) and a black hole taking matter from the normal star. ...

Subject, Problems and Objects of Theoretical Astrophysics. ... Stellar Photospheres, Their Features. ... Physics of Continuous Radiation Absorption in Stellar Photospheres. ... Continuous Radiation Absorption in Stellar Photospheres of Various Spectral Classes. Solar Type Photospheres. ... Characterisics of Absorption Lines. ... Interstellar Absorption Lines, Their Features. ... Physical and Dynamic Features of Interstellar Medium, Which Follows from Observations of Interstellar Absorption Lines. ...

Gravitational four-fermion interaction and dynamics of the early Universe I.B. Khriplovich, A.S. Rudenko Budker Institute of Nuclear Physics, 630090 Novosibirsk, Russia October 2013 According to common beliefs, present expansion of Universe is result of Big Bang. Quite popular idea is that this expansion had been preceded by compression with subsequent Big Bounce. ... Its energy density is = n4/3, is numerical factor, n1/3 is typical energy per particle. ... Solution of FLRW equations. ...

... The GALFA Continuum Transit Survey group ( GALFACTS ; PI: A. R. Taylor) has conducted several test observations and will begin an all-sky full-Stokes continuum survey later this year with the new P-ALFA spectrometer. ... Sample Perseus images of GALFA H I 21cm-line and full-Stokes continuum emission are shown below along with maps of molecular (CO) gas, thermal dust, and ionized gas optical emission for comparison. ... The GALFA H I emission appears to envelop the molecular cloud gas traced by CO. ...

... ROTATION CURVE: When studying spiral galaxies it is invariably found that the stellar rotational velocity in the disk remains constant, or "flat", with increasing distance away from the galactic center. ... The rotation speed of the stars in galaxies is found NOT to decrease with increasing distance from the galactic center (see emission lines in the spectrum), implying that the overall mass distribution of the galaxy is different from the light distribution. ...

... In brief: the frequency-dependent radiative transfer equation is solved for a dust under assumption of spherically-symmetric geometry for its distribution taking into account particle size distribution and quantum heating effects for the very small dust particles. ... Table: Model parameters for IRAS04296+3429. ... parameter . ... hot dust shell) . ... The best fit to the spectral energy distribution of IRAS04296 is shown by heavy solid line (see Table2 for details concerning parameters of the model...

... Particle Sizes in Saturns Rings . ... Credit: RSS , JPL , ESA , NASA Explanation: What size particles compose Saturn's rings? To help find out, the robot Cassini spacecraft now orbiting Saturn broadcast radio waves of three different wavelengths right through the rings to Earth earlier this month. The experiment was sensitive to ring particle sizes because ring particles much larger than a broadcast radio wavelength will reflect those radio waves away. ... NASA Official: Jay Norris. ...