... Be Stars . ... Stellar Winds . ... He had found the first emission line star. ... More emission line stars were found soon, and one had to make subclasses to keep some overview. Cas is a main sequence B-type star, and together with other such stars showing hydrogen emission it forms the class of "Be stars", where the "e" stands for emission. ... Struve further speculated that those stars would be surrounded by a disk, basically thrown off the stellar surface by the rapid rotation. ...

... Bad Astronomy . ... Mad Science . ... Site Info . ... Public Talks . ... Keep Bad Astronomy close to your heart, and help make me filthy rich. ... Who is this guy who calls himself "The Bad Astronomer?" ... First, yes, I am a real live astronomer (when people ask me what astronomers do, I tell them "They astronom !" ... These are emitted by powerful objects like black holes, exploding stars, and super-dense neutrons stars. ... Finally, am I really a bad astronomer? ... 2008 Phil Plait. ...

... Takuya Akahori "Faraday Rotation Measure due to the Intergalactic Magnetic Field" . Shae Brown "Cross-correlation of ATLAS and Spitzer-SWIRE Surveys: Probing intergalactic magnetic fields" . Roger Clay "Using low energy cosmic rays to investigate local galactic magnetic fields" . Roland Crocker "A new lower limit on the magnetic field around the Galactic Centre" . ... JinLin Han "Rotation measures of pulsars and radio sources for Galactic magnetic fields" . ...

Astronomers Detect Coolest Radio Star . ... The new radio-star is much smaller and colder than our Sun.€а With a surface temperature not much higher than that of a giant planet, and a size comparable to JupiterтАЩs, it is scarcely visible in optical light.€а Yet the radio flares seen at Arecibo show it must have a strong magnetic field, implying that the same could be true of other similar stars. ...

The Sun is our nearest star and the source of energy for life on Earth. ... For centuries astronomers wondered whether they were clouds floating in the Sun's atmosphere, but we now know that they really are huge regions of magnetic field, about as intense as the field at the poles of an iron magnet. ... Such abrupt events were named solar flares , and what made them especially interesting was that occasionally, after a prominent flare, a magnetic storm would erupt on Earth. ...

Synchrotron Radiation Emission from relativistic electrons gyrating round magnetic field lines. ... Different spectrum ( - optically thick - optically thin #" ! ... Can calculate radiated power from Larmor's equation. dipole pattern Mildly Relativistic Electrons Even for , relativistic beaming changes emitted spectrum significantly. Depar ture from dipole pattern and spectrum no longer a single emission line. gf !e d c 'b a` Y X h Ultra-Relativistic Electrons: Synchrotron Radiation B e v v|| v_ | ...

... Solar flare activity is produced by the processes of accumulation and release of energy in an active region. ... In the framework of study of solar active regions, producing powerful flares the researchers from the RATAN-600 radio telescope have detected sources with features in the form of a sharp drop in the intensity of polarized radiation in various parts of the recorded frequency range (2-16GHz), sometimes changing the sign of polarization. ...

... Observing . ... Solar Observing . ... April 3 (SUN) - Solar Observing, Central Park , Manhattan . ... APRIL'S SKY . ... Lecture Series at the American Museum of Natural History The Amateur Astronomers Association is proud to present an astronomy lecture series from October through May each year for our members and the .. ... The€аAmateur Astronomers Association of New York€аwas organized in 1927 to promote the study of Astronomy, emphasizing its cultural and inspirational value. ...

M. ( / DIAS, Ireland), A. (ISDC, Switzerland) 1 - Key Question Only 3 binary systems regularly observed in TeV: PSR B1259-63 (young pulsar +Be star, P=3.4 y) LSI +61 303 (comp. source + Be star, P=26.42 d) LS 5039 (comp. source + O star, P=3.9 d) Origin of the high-energy emission? ... 2006; Neronov &Chernyakova 2007 4 3.4 years orbital period. e~0.87 Correlated variability with a sharp rise ( "two bumps structure" ) is seen in radio, X-ray (and TeV?) bands. ...

Next: M.E. Bailey, Director Up: Research Previous: C.S. Jeffery, Research Astronomer Contents . Dr Michael Smith has focused mainly on the earliest stages of stellar evolution: the processes leading to star formation from an initially unstable, collapsing cloud of gas, and the energetic outflows -- jets and winds -- associated with the formation and early evolution of protostars and pre-main-sequence stellar objects. ... Spectacular jets of molecules, however, betray its presence. ...

http://hubblesite.org/newscenter/archive/releases/1996/22/text/ Probing the mysterious heart of the Crab Nebula, the tattered remains of a stellar cataclysm witnessed more than 900 years ago, astronomers using NASA's Hubble Space Telescope have found that the Crab is even more dynamic than previously understood, based on a cosmic "movie" assembled from a series of Hubble observations. ... Because of this flickering, the neutron star is also called a "pulsar." ...

Most current theories for magnetospheric emission can be grouped into polar cap, outer gap, and nebular models. These models, at least in some cases, need not be mutually exclusive; the Crab pulsar (among others), for example, shows clear evidence for pulsed emission from the magnetosphere and unpulsed emission from the surrounding nebula. ... This suggestion is strengthened by observation of a distinct soft emission component, consistent with the cooling scenario, from several of these pulsars. ...

ST ScI Preprint #1392 . ... This has accentuated the biases inherent in any survey to favor objects which are bright in the survey band, and should serve as a cautionary note both to those designing new surveys as well as theorists attempting to model blazar properties. ... Two new surveys have detected a large population of high-energy peaked emission line blazars (FSRQ), with properties somewhat different from previously known objects. ... Among these are several high-energy peaked FSRQ. ...

... Research . ... A rare hybrid morphology radio galaxy . ... In this project we will be able to investigate the environmental effect on star formation and galaxy evolution in individual galaxies falling into the cluster through radio observations of active galactic nuclei (AGN). Current models of galaxy evolution regulate the star formation rates within the simulated galaxies by invoking radio-mode feedback from AGN. ... Julie.Banfield@anu.edu.au . ...

... The Sun gives us light and heat, sustaining life on Earth. ... This uneven rotation, coupled with the churning of the upper layers, might well be what produces (by a "dynamo mechanism", described in a later section) regions of intense magnetic field, seen by observers on Earth as dark sunspots. ... Near sunspots those streamers seem to be shaped by the Sun's magnetic field lines, and above the Sun's poles they suggest field lines rising from twin magnetic poles like those of the Earth. ...

The Variable Gamma-Ray Source 2CG 135+01 ApJ, 497:L89-L91, 1998 7 h gamma AGN variability . gamma-radio-AGN-variability ADS query . ... Model for the High-Energy Emission from Blazars 1993ApJ.. ... Possible Production of High-Energy Gamma Rays from Proton Acceleration in the Extragalactic Radio Source Markarian 501 astro-ph/9803241 K.Mannheim . ... A theoretical unifying scheme for gamma-ray bright blazars astro-ph/9807317 G. Ghisellini, A. Celotti, G. Fossati, L. Maraschi, A. Comastri . ...

... Almost out of view from our fair planet, rotating around the Sun's western edge, giant sunspot region AR 10486 lashed out with another intense solar flare followed by a large coronal mass ejection (CME) on Tuesday, November 4th at about 1950 Universal Time. ... Northern and southern locales saw many a beautiful aurora over the last week, as particles from several large solar flares impacted the Earth. ... Yesterday, our Sun produced one of the most powerful solar flares in recorded history. ...

... 2008 October 21 . A Dark Pulsar in CTA 1 . Credit: NASA , S. Pineault ( DRAO ) . Explanation: Where's the pulsar? Previously, the nebula CTA 1 showed an expanding supernova remnant , a jet , and a point source expected to be a pulsar -- a rotating neutron star producing pulses at radio energies. ... Now NASA's recently deployed Fermi Space Telescope has solved the mystery with some of its initial observations indicating that the point source is pulsing at gamma-ray energies . ...