function flux _to_em, emis , flux = flux , logT = logT , wvl = wvl ,Z=Z,NH=NH,defEM=defEM,$ noph=noph, thresh = thresh , _extra=e ;+ ;function flux _to_em ; return emission measures (-1 where undeterminable) at various ; temperatures consistent with given line fluxes and line emissivities. ; ; for each temperature, assume a delta-function emission measure, ; compute ...

... Armagh Observatory, College Hill, Armagh BT61 9DG, +44 (0)28 3752 2928 . Figure 1: Dynamic spectrum of Jovian radio emission recorded by Cassini on October 21, 2000 (courtesy of W.S. Kurth, Cassini RPWS Team, University of Iowa). ... We investigate the formation of zebra-like fine spectral structures (consisting of several parallel bands in the dynamic spectrum) in the Jovian broadband kilometric radiation; such radio bursts were observed by Cassini in 2000/2001. ...

... ATNF Home . ... About ATNF overview . ... Australia Telescope Steering Committee . ... Australia Telescope User Committee . ... Murchison Radio-astronomy Observatory . ... Parkes radio telescope . Australia Telescope Compact Array . ... Visiting Parkes radio telescope . ... Parkes radio telescope webcam . ... PULSE@Parkes . ... The project does not assume any detailed prior knowledge of pulsar astronomy though students should have studied astronomy as a component of Stage 4 Science (Years 7-8). ...

We cannot observe the way the distant universe accelerates cosmic rays or produces energetic photons, but acceleration processes also occur on our Sun , though on a much more moderate scale. ... That is why such events are often missed by cosmic ray detectors near the equator, where the lowest energies are excluded by the Earth's magnetic field. The best detectors for observing solar particles are therefore those sensitive to the lowest energies of the cosmic radiation. ...

... Authors: Mario Livio It is assumed that the acceleration and collimation mechanisms of jets are the same in all the classes of astrophysical objects which are observed to produce jets. These classes now include such objects as: active galactic nuclei, young stellar objects, massive x-ray binaries, low mass x-ray binaries, black hole x-ray transients, symbiotic systems, planetary nebulae, and supersoft x-ray sources. ... huizinga@stsci.edu . ...

... 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. ...

Bigbang Forum Message . ... Big Bang | ... Big Bang: Nagging Doubts Remain . ... I recently read 2 books by Simon Singh: Fermats Last Theorem and The Big Bang. ... No matter how many proofs there are to support a theory, if it is not mathematical then there will always remain an element of doubt as to the accuracy of that theory. ... www.astronomy.net . ... Forum posts are Copyright their authors as specified in the heading above the post. "dbHTML," "AstroGuide," "ASTRONOMY.NET" & "VA.NET" . ...

... A Hubble diagram for Quasars . ... The potential use of such relation as a cosmological probe is obvious: assuming no redshift evolution of the relation, the observed X-ray flux is a function of the observed UV flux, the redshift, and the parameters of the adopted cosmological model. ... In this framework, Guido Risaliti and Elisabeta Lusso (INAF-Arcetri Observatory) have recently published in the Astropysical Journal the first Hubble Diagram for quasars suitable for cosmological measurements . ...

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. ...

... Searching for Far Out and Wandering Worlds . ... The Real Reality Show: Would aliens be anything like us? ... The SETI Institute is after alien signals. Assuming another world is beaming a 1-million-watt radio signal in our direction, how far away can that source be before the signal is lost in intergalactic noise? ... Get instant access to subscriber content on Astronomy.com! ... If you are already registered on Astronomy.com, please log in below. ...

HI spectral-line observations of galaxies (Karen O'Neil) . Measuring the width, flux, etc. of the HI profile of two galaxies, using some combination of : dwarf emission line, HVC emission line, spiral emission line, and spiral absorption line. This project was designed to demonstrate the fundamentals of spectral line observing and position switching. ... The types of galaxies observed in this project are being kept open and will be determined when the project LST is known. ...

CONTINUUM AND BROAD EMISSION LINE VARIABILITY OF SEYFERT GALAXIES V.T. Doroshenko 1,2 , S.G. Sergeev 2 , V.I. Pronik 2 1 Crimean Lab. of the Sternberg Astronomical Institute, Moscow University, Russia 2 Scientific­Research Institute, Crimean Astrophysical Observatory, Ukraine; p/o Nauchny, 98409, Crimea, Ukraine vdorosh@sai.crimea.ua We focused on the observed properties of some Seyfert galaxies without detailed discussion of underlying physical mechanisms. ...

... Magnetic Storms . ... Cosmic Rays . ... Energetic Particles . ... Solar fast Particles . We cannot observe the way the distant universe accelerates cosmic rays or produces energetic photons, but acceleration processes also occur on our Sun , though on a much more moderate scale. ... That is why such events are often missed by cosmic ray detectors near the equator, where the lowest energies are excluded by the Earth's magnetic field. ... Should we be concerned about solar energetic radiation? ...

... Galaxies 99 Cosmic background with model of cloudy interstellar medium Yu. ... Figure 1: Averaged spectrum of the cosmic background I f in frequency range 0.25 200 MHz for the Galactic poles. ... First interpretation of the cosmic noise background spectrum at broad band frequency range 0.25 200 MHz with a model of the cloudy interstellar medium ISM is presented here. ... Synthesized background spectra I f for regions of the Galactic poles at the frequency range 0.25 200 MHz is presented in Fig. ...

... W. Steffen , T.P. Krichbaum , S. Britzen and A. Witzel . ... Such oscillations can result from precession of the jet, helical magnetic fields, or helical instabilities. ... VLBI monitoring of the milliarcsecond scale structure shows stationary components at about 5, 1.4 and 0.4 mas separation from the core ( Eckart et al. ... The accumulated VLBI data show that the observed components and the continuous jet structure are aligned along a curved, oscillating ridge line (see Figure 1 ). ...

... A glance at the article might leave you assuming that the planet was discovered using a large telescope at a remote, high-elevation location or perhaps by a multi- billion dollar observatory in Earth orbit. Reading on, you may be surprised to find that astronomers actually discovered the planet with a small telescope located not too far from the city of Tucson, Arizona. ... Well, don't give up, because you can observe interesting celestial sights near low-elevation big cities. ...

... ON THE ROLE OF LARGE-SCALE PLASMA IRREGULARITIES AT THE FINAL STAGE OF ANOMALOUS ABSOPTION DEVELOPING UNDER HF HEATING OF THE IONOSPHERE . ... Fig. ... With the aid of numerical statistical modeling based on multiple ray tracing it is shown that in presence of large-scale irregularities the reflected signal amplitude mean value is increased significantly. ... Dependence of the mean amplitude of the reflected from the ionosphere signal on the large-scale (10-50 km) electron density irregularity level...

... Science User Portal . ... ESO, the European Southern Observatory . ... ESO's Governing Bodies . ... Travel and Contacts . Travel to ESO Headquarters . ... ESO . ... Survey Telescopes . ... Star Clusters . ... Stars@ESO . ... ESO Science Newsletter . ... ESO 3.6-metre telescope . HARPS . MPG/ESO 2.2-metre telescope . ... ESO 1-metre Schmidt telescope . ... ESO Science Outreach Network . ... Illustration of the high-quality radial velocity measurements obtained with HARPS. ... mu Arae . ...

Mikhail Medvedev (University of Kansas) HEA- 2007 , IKI, Moscow Missing baryons in inter-cluster gas Afshordi, et al, 2007 , astro-ph/0612700 35% +/- 8% Sample of 260 clusters WMAP SZ 3yr data Compared with 11 simulated clusters Assumed: Universal NFW profile Self-similarity Isothermal gas Possible explanations Observed stellar mass in galaxies: ~ 10% (Lin, et al, ... Simulations indicate that the effect is small (Dolag, et al, 2004) Can account for ~1-2% missing mass at most ...

... About ATMoB . ... The Observing Committee is starting an Observing Awards Program to promote observing among the membership of the Amateur Telescope Makers of Boston. ... Participant must be a current member of the Amateur Telescope Makers of Boston . ... To qualify for your Observing Award Certificate, turn in your worksheet and drawings to an ATMoB Observing Committee member or observing@atmob.org . ... This Excel sheet has useful macros. ... Copyright (c) Amateur Telescope Makers of Boston, Inc. ...