Portal:Radiation astronomy/Lecture

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Radiation astronomy entities

This is an image of Johannes Vermeer's The astronomer. Credit: www.essentialvermeer.com : Home : Info : Pic.

Radiation astronomy entities, radiation entities, are any astronomical persons or things that have separate and distinct existences in empirical, objective or conceptual reality.

Some of them, like the astronomers of today, or at any time in the past, are relatively known. But there are many entities that are far less known or understood, such as the observers of ancient times who suggested that deities occupied the sky or the heavens. Likewise, these alleged deities may be entities, or perhaps something a whole lot less.

Astronomical X-ray entities are often discriminated further into sources or objects when more information becomes available, including that from other radiation astronomies.

A researcher who turns on an X-ray generator to study the X-ray emissions in a laboratory so as to understand an apparent astronomical X-ray source is an astronomical X-ray entity. So is one who writes an article about such efforts or a computer simulation to possibly represent such a source.

"The X-ray luminosity of the dominant group [an entity] is an order of magnitude fainter than that of the X-ray jet."[1]

References

  1. A. Finoguenov, M.G. Watson, M. Tanaka, C.Simpson, M. Cirasuolo, J.S. Dunlop, J.A. Peacock, D. Farrah, M. Akiyama, Y. Ueda, V. Smolčič, G. Stewart, S. Rawlings, C.vanBreukelen, O. Almaini, L.Clewley, D.G. Bonfield, M.J. Jarvis, J.M. Barr, S. Foucaud, R.J. McLure, K. Sekiguchi, E. Egami (April 2010). "X-ray groups and clusters of galaxies in the Subaru-XMM Deep Field". Monthly Notices of the Royal Astronomical Society 403 (4): 2063-76. doi:10.1111/j.1365-2966.2010.16256.x. http://onlinelibrary.wiley.com/doi/10.1111/j.1365-2966.2010.16256.x/full. Retrieved 2011-12-09. 



Radiation astronomy sources

Volcanic bombs are thrown into the sky and travel some distance before returning to the ground. This bomb is in the Craters of the Moon National Monument and Preserve, Idaho, USA. Credit: National Park Service.

In source astronomy, the question is "Where did it come from?"

Source astronomy has its origins in the actions of intelligent life on Earth when they noticed things or entities falling from above and became aware of the sky. Sometimes what they noticed is an acorn or walnut being dropped on them or thrown at them by a squirrel in a tree. Other events coupled with keen intellect allowed these life forms to deduce that some entities falling from the sky are coming down from locations higher than the tops of local trees.

Def. a source or apparent source detected or “created at or near the time of the [ event or] events”[1] is called a primary source.

Direct observation and tracking of the origination and trajectories of falling entities such as volcanic bombs presented early intelligent life with vital albeit sometimes dangerous opportunities to compose the science that led to source astronomy.

References

  1. primary source. San Francisco, California: Wikimedia Foundation, Inc. February 16, 2012. Retrieved 2012-07-14.



Radiation astronomy objects

The image shows a chain of craters on Ganymede. Credit: Galileo Project, Brown University, JPL, NASA.

Def. a hemispherical pit a basinlike opening or mouth about which a cone is often built up any large roughly circular depression or hole is called a crater.

The image at right shows a chain of 13 craters (Enki Catena) on Ganymede measuring 161.3 km in length. "The Enki craters formed across the sharp boundary between areas of bright terrain and dark terrain, delimited by a thin trough running diagonally across the center of this image. The ejecta deposit surrounding the craters appears very bright on the bright terrain. Even though all the craters formed nearly simultaneously, it is difficult to discern any ejecta deposit on the dark terrain.




Strong forces

"In field theory it is known that coupling constants “run”. This means that the values of the coupling constants that one measures depend on the energy at which the measurement is performed. [...] the three different coupling constants [one each for the strong force, electromagnetic force, and the weak force] of the standard model seem to converge to the same value at an energy scale of about 1016 GeV [...] This suggests that there is only one coupling constant at high energies and most likely only one symmetry group. [...] The current belief [is] that the electromagnetic, weak and strong forces [are] unified at about 1016 GeV [as such] one has to rely on [the] particle physics interactions which can lead to electromagnetic radiation and cosmic rays".[1]

References

  1. Tanmay Vachaspati (1998). "Topological defects in the cosmos and lab". Contemporary Physics 39 (4): 225-37. doi:10.1080/001075198181928. http://www.tandfonline.com/doi/abs/10.1080/001075198181928. Retrieved 2013-11-05. 



Electromagnetic forces

The electric vectors of PKS0521-36 show clear structure and alignment. Credit: Keel.

"The emission of electromagnetic radiation from a superluminal (faster-than-light in vacuo) charged particle [is such] that no physical principle forbids emission by extended, massless superluminal sources. A polarization current density (dP/dt; see Maxwell's fourth equation) can provide such a source; the individual charged particles creating the polarization do not move faster than c, the speed of light, and yet it is relatively trivial to make the envelope of the polarization current density to do so."[1]

The "emitted radiation has many unusual characteristics, including: (i) the intensity of some components decays as the inverse of the distance from the source, rather than as 1/(distance)2 (i.e. these components are non-spherically-decaying); (ii) the emission is tightly beamed, the exact direction of the beam depending on the source speed; and (iii) the emission contains very high frequencies not present in the synthesis of the source. Note that the non-spherically decaying components of the radiation do not violate energy conservation. They result from the reception, during a short time period, of radiation emitted over a considerably longer period of (retarded) source time; their strong electromagnetic fields are compensated by weak fields elsewhere [1]."[1]

The "emission occupies a very small polar angular width of order 0.8 degrees in the far field. Based on these findings, we suggest that a superluminal source could act as a highly directional transmitter of MHz or THz signals over very long distances."[1]

"The magnetic field is well-ordered in many jets, as shown by polarization measurements. Synchrotron radiation can be very highly polarized (50%) if the field is globally ordered, and some sources [approach] this level. The electric vectors show clear structure and alignment; an especially common pattern is for the field lines to be along the jet in the inner portions and transition to an azimuthal configuration farther out. This is seen in [PKS0521-36 at 2 cm]."[2]

References

  1. 1.0 1.1 1.2 J. Singleton, A. Ardavan, H. Ardavan, J. Fopma and D. Halliday (2005). Non-spherically-decaying radiation from an oscillating superluminal polarization current: possible low-power, deep-space communication applications in the MHz and THz bands, 16th International Symposium on Space Terahertz Technology (PDF). p. 117. Retrieved 2014-03-18.CS1 maint: multiple names: authors list (link)
  2. Bill Keel (October 2003). Jets, Superluminal Motion, and Gamma-Ray Bursts. Tucson, Arizona USA: University of Arizona. Retrieved 2014-03-19.



Weak forces

The diagram shows beta-minus decay from a nucleus. Credit: Inductiveload.

The weak interaction is expressed with respect to nuclear electrons and the continuous β-ray emission spectrum of β decay.[1]

"The observation of a neutrino burst within 3 h of the associated optical burst from supernova 1987A in the Large Magellanic Cloud provides a new test of the weak equivalence principle, by demonstrating that neutrinos and photons follow the same trajectories in the gravitational field of the galaxy."[2]

References

  1. Fred L. Wilson (December 1968). "Fermi's Theory of Beta Decay". American Journal of Physics 36 (12): 1150-60. http://microboone-docdb.fnal.gov/cgi-bin/RetrieveFile?docid=953;filename=FermiBetaDecay1934.pdf;version=1. Retrieved 2012-06-24. 
  2. Lawrence M. Krauss, Scott Tremaine (January 1988). "Test of the Weak Equivalence Principle for Neutrinos and Photons". Physical Review Letters 60 (3): 176–7. doi:10.1103/PhysRevLett.60.176. http://link.aps.org/doi/10.1103/PhysRevLett.60.176. 



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