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. ...

... In the first page of this chapter, Eddington computes an effective temperature of 3.18 K, but this has nothing to do with the 2.725 K blackbody spectrum of the Cosmic Microwave Background (CMB) . Here is a quote of what Eddington actually said: . ... We shall first calculate the energy density of this radiation. ... It is clear that Eddington's model fits the optical data, but that Eddington did not anticipate either the CMB (red curve) or the interstellar dust (ISD, green curve). ...

The sband wide receiver has resonances in the OMT. ... A simplified model of the system temperature including these resonances is: Tsys= Tomt*alpha + (1-alpha)*Tsky + Tamp. ... Rewriting the equation: Tsys= Tsky + Tamp + alpha*(Tomt-Tsky) Shows that the spectral density at the resonance will increase or decrease (relative to the adjacent frequencies) depending on whether or not (Tomt-Tsky) is positive or negative. ... black - spectral density on the absorber . red - spectral density on the sky . ...

... Luminosity (L) · · · · A source's luminosity is the power that it emits in radiation. ... NB Astronomers often say `flux' when they mean `flux density' · SI units are Wm-2Hz -1 -26 filter · Also used are Jy 10 Wm-2Hz -1 E= РРРF d dA dt Specific Intensity, Surface Brightness (I) · Specific intensity (or surface brightness) is the power received (or emitted) per unit area per unit frequency per unit solid angle. ч F at surface of a spherical source = I · · Specific intensity is independent of distance...

Superconducting Integrated Submm Spectrometer for Laboratory Applications Specification: · Input frequency range : 200 ­ 700 GHz (covered by four exchangeable sensor modules each one covering range of about 100-150 GHz ); · Output frequency (IF) range : 1-2 GHz · Receiver noise temperature: below 500 K (direct ... The SIR chip is a superconducting integrated circuit comprising a quantum-noise-limited SIS mixer and a tunable Josephson local oscillator (LO). ...

... About ATNF overview . ... Parkes radio telescope . ... Saxton & Wu (1999) presented calculations of the stability of the accretion shock which forms on the surface of an accreting magnetic white dwarf in AM Herculis type systems in an attempt to explain the observed properties of the quasi periodic oscillations sometimes seen in these systems. He showed that radiative cooling may cause thermal instability in the post-shock structure of the accretion flow settling onto a magnetic white dwarf. ...

In the PROJECT we are using the following peculiar . features of RATAN-600 . ... Brightness temperature sensitivity being equal to the antenna temperature sensitivity .. ... Receiver system .. ... Using aperture averaging effect. dual- beam and dual (multi-) frequency filtration, we demonstrated full filtration of the atmosphere noise down to the receiver noise at all scales of acoustics peaks ( Fig.1 , Fig 2 ). ... We select this frequency as the central one in our project. ... Antenna surface . ...

Microsymposium 34, MS058, 2001 ANOMALIES OF THE MOON'S THERMAL EMISSION IN THE IR SPECTRAL RANGE (10.5 - 12.5 micron). ... Sternberg State Astronomical Institute, Moscow, 119899, Russia, pugach@sai.msu.ru Summary: New satellite measurements of the lunar-surface radiation temperature were used to construct the spatial angular function of thermal radiation of the Moon in the infrared (10.5-12.5 micron) spectral range. ... These thermal anomalies are observed only in the limited range of phase angles. ...

... The basic principles of incoherent scatter: . ... Because of the electron movement, spectrum of the observed signal is broad and it has shape which depends, e.g., on the temperature. ... ion temperature . ... According to the theory, Ti should be replaced by (2Ti,perp + Ti,par)/3 (Williams and Jain,1986; Glatthor and Hernandez, 1990; Winser et al., 1990). ... Glatthor, N., and R. Hernandez, Temperature anisotropy of drifting ions in the auroral F-region, observed by EISCAT, J. atmos. terr. ...

... Archives . ... Like spherical cows , true blackbodies do not exist. ... black here simply refers to the property of the object where no wavelength is preferentially absorbed or emitted, and all the energy input to it is converted into radiation. ... The blackbody spectrum is . B_{\nu}(T) = \frac{2 h \nu^3}{c^2} \frac{1}{e^{h \nu / k_B T} ? ... The general shape of a blackbody spectrum is like a rising parabola at low ? ... Comment ( RSS ) | ... Chandra Blog . ... Entries (RSS) and Comments (RSS) . ...

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... STIS . ... In a space environment, CCD detectors accumulate radiation damage, which over time leads to increasing dark current, more hot pixels, and reduced charge transfer efficiency. After twelve years on orbit, the effects of such radiation damage on the STIS CCD have become substantial. ... Since in a CCD, charge must be transferred many times before reaching the readout register, even a small decrease in CTE can have a large effect on the measured count rate near the center of the detector. ...

... A. M. Neminsky, P. N. Nikolaev, and D. V. Shovkun . ... The temperature dependence of the magnetic field penetration depth lambda ( T ) is determined down to 0.2 T c by the ac-susceptibility measurements on the Rb 3 C 60 fine powder with small, about 1 K, variation in the grains' superconducting transition temperatures. The lambda ( T ) temperature dependence is exponential at low temperatures, which allows us to determine the energy gap Delta 0 =1.7 k B T c . ...

XMM-Newton Science Analysis System . ... These subroutines calculate the power (in watts) radiated per unit surface area (m2) per unit solid angle (sr) by a black body at temperature='kelvin'. The power can be calculated either per unit frequency, at a given frequency (both in hertz), or per unit wavelength (in metres) at a given supplied wavelength (in angstroms). ... Per unit frequency . Per unit wavelength . XMM-Newton SOC/SSC -- 2008-07-01 ...

Instruments and Methods 133 Sky temperature resolution by microwave radiometry A.G. Kislyakov State University, Nizhny Novgorod, Russia Introduction The threshold sensitivity of a radiometer is determined by well known equation Karlov & Manenkov, 1966 " hE i = h hn i +1 hn i + N t G0 , 1 G0 1=2 : 1 Here we denote hE ias the minimum detectable increment of radiation spectral density E at a frequency . ... Equation 3 gives a correction to the expression for limit detector sensitivity Kislyakov, 1997. ...

If an object emits a total power (energy per unit time) L (L for luminosity), this radiation will spread outward into space, becoming more spread-out and diffuse as it goes. ... If an object receives more heat than it dissipates, then its temperature will rise. ... Any object at a temperature above absolute zero will radiate energy. ... A is the surface area of the black body, T is its temperature, and s = 5.67 « 10 -8 Wm -2 K -4 (the Stefan-Boltzmann constant). ...

The hotbed effect (hothouse effect) in the planets atmosphere is the inside atmosphere layers heating (of the Earth, Venus etc.), due to the transparent planet atmosphere for the main part of solar radiation (in optical range). In the atmosphere of the Earth this radiation is absorbed by the molecules of H2O, C02, O3 and others. ... As a result of human activities the CO2 content is increasing (and the other gases, absorbing in infrared range). ...

TEST RESULTS WITH 2KX2K MCT ARRAYS Finger, G, Dorn, R.J., Mehrgan, H., Meyer, M., Moorwood A.F.M. and Stegmeier, J. European Southern Observatory Abstract: The performance of both an LPE 2Kx2K engineering grade and a science grade array have been evaluated. Both arrays have a cut-off wavelength of c=2.6 µm. At an operating temperature of 60 K, the dark current of the science grade array is 0.004 e/s. The peak quantum efficiency of the science grade array is 84.4%. ...

The CHIANTI database consists of 4 primary ASCII files for each ion in the database. contains the energy levels in cm^(-1) It includes both experimental data and theoretical values of the levels energies. ... contains the spline fits to the electron collision strengths scaled according to Burgess and Tully (1992). ... References: %filename: si_9.psplups %rates: Ryans R.S.I., Foster-Woods V.J, Keenan F.P., Reid R.H.G., 1999, ADNDT 73, 1-42 %energies: CHIANTI database, ver.1, Dere et al., ...

Observation and modelling of main sequence star chromospheres. ... We compare our calculations to recent high res­ olution observations for selected stars in a narrow spectral range ((R­I) џ =0.875\Sigma0.05); we show that Hff line profiles behave as expected, with a tight correlation be­ tween the line width and equivalent width. ... We show that the hydrogen series dominate the radiative cooling in the spectral lines (form 40% to 90%) for Hff emission line stars. ...