Galactic and Cosmology Section
Section Coordinator: David Westman david_westman@iinet.com
Background and Context
In 1931 Karl Jansky accidentally discovered naturally occurring radio emissions from the sky. The inexplicable source of radio noise was identified in 1940 by Gröte Reber, using a radio telescope in the backyard of his home, as originating from our own galaxy, the Milky Way. Today, amateur radio astronomers can detect these same emissions and many others outside the galaxy.
Radio Galaxy Zoo is the prominent citizen science project of the Galactic and Cosmology Section. It seeks to learn more about the formation of super massive black holes that are present at the center of galaxies with the help of crowd-sourced data mining. Due to the nature of black holes, the scientists composing the Radio Galaxy team analyze the surroundings of the formations due their inability to study the holes themselves. Using telescopic and satellite imaging, Radio Galaxy Zoo allows citizens to identify characteristics of galaxies in an attempt to synthesize more information about black holes, which is necessary to understand their origins.
Radio Galaxy Zoo can be found at:
https://radio.galaxyzoo.org/
Two professional papers highlighting the success of the program are found here:
Radio Galaxy Zoo: Discovery of a poor cluster through a giant wide-angle tail radio galaxy http://mnras.oxfordjournals.org/content/460/3/2376.full
Radio Galaxy Zoo: Host galaxies and radio morphologies derived from visual inspection http://mnras.oxfordjournals.org/content/453/3/2326.full
Galactic Center
The galactic center of the Milky Way was the first radio source to be detected. It contains a number of radio sources, including Sagittarius A and the supermassive black hole at its center.
Related Radio Astronomy Project(s) and/or Information:
https://groups.google.com/forum/#!topic/sara-list/eCiVuKXvHLU
http://radiojove.gsfc.nasa.gov/library/sci_briefs/galactic.html
http://radiojove.gsfc.nasa.gov/observing/sample_data.htm
Extra-Galactic
Radio waves also originate from outside the Milky Way. These radio sources have great implications for cosmology. Spiral galaxies, such as the Milky Way, are weak sources of radio waves, but certain giant elliptical and irregular galaxies emit more than a million times as much radio energy as ordinary galaxies.
Related Radio Astronomy Project(s) and/or Information:
http://www.dmradas.co.uk/new%20files%20dec%202011/RAG%20site%20pdfs/Dete...
http://www.britastro.org/radio/RadioSources/extragalactic.html
Star Forming Regions
Astronomers studying the Milky Way have discovered a large number of star forming areas. Their discovery provides important information about the structure and chemical composition of our galaxy.
Related Radio Astronomy Project(s) and/or Information:
Star formation in U,B,V,R and I bands: http://www.faulkes-telescope.com/news/2316
Radio Galaxies and Quasars
Radio galaxies and their relatives, radio-loud quasars and blazars, are types of active galaxy that are very luminous at radio wavelengths. Quasars or quasi-stellar radio sources are the most energetic and distant members of a class of objects called active galactic nuclei (AGN). Quasars were first identified as being high redshift sources of electromagnetic energy, that appeared to be similar to stars, rather than extended sources similar to galaxies. Their spectra contain very broad emission lines, unlike any known from stars, hence the name "quasi-stellar". Their luminosity can be 100 times greater than the Milky Way.
An optical observing program of Active Galactic Nucleus (AGN) galaxies, which include radio galaxies, is found at the Astronomical League website:
https://www.astroleague.org/programs/active-galactic-nuclei-observing-pr...
High energy / Gamma Ray Astronomy
Gamma-ray astronomy is the astronomical observation of gamma rays, the most energetic form of electromagnetic radiation.
Related Radio Astronomy Project(s) and/or Information:
http://www.radio-astronomy.org/node/115
http://www.radio-astronomy.org/pdf/projects/grb0809.pdf
http://www.radio-astronomy.org/node/40
Cosmic Microwave Background (CMB)
The CMB, discovered in 1964, is the thermal radiation assumed to be remaining from the "Big Bang" of cosmology. The CMB is a cosmic background radiation is the oldest radiation in the universe. With a traditional optical telescope, the space between stars and galaxies (the background) is completely dark. However, a radio telescope can show a faint background glow, almost exactly the same in all directions, that is not associated with any object. This glow is strongest in the microwave region of the radio spectrum.
Related Radio Astronomy Project(s) and/or Information:
https://groups.google.com/forum/#!topic/sara-list/0_9UQnKyCCs
Methanol Line Radio Astronomy
In 1965 emission lines of molecules were discovered in space. More discoveries followed, including methanol, CH3OH, emissions in 1970 coming from within molecular clouds. These were termed masers, as from their narrow line-widths and high effective temperatures it became clear that these sources were amplifying microwave radiation.
Related Radio Astronomy Project(s) and/or Information:
http://www.jupiterspacestation.org/BernardPaperInternet.html
Hydrogen Line Radio Astronomy
The hydrogen line, or HI line, refers to the electromagnetic radiation spectral line that is created by a change in the energy state of neutral hydrogen atoms. It has a precise frequency of 1420.4 MHz, which is equivalent to the vacuum wavelength of 21.1 cm in free space. It is observed frequently in radio astronomy, since those radio waves can penetrate the large clouds of interstellar cosmic dust that are opaque to visible light.
70th Anniversary of the Discovery of Radio Emissions from Neutral Hydrogen
Related Radio Astronomy Project(s) and/or Information:
http://y1pwe.co.uk/RAProgs/index.html
https://britastro.org/node/19862
Hydrogen Line Observing in Nearby Galaxies Using Drift Scanning With a Small Dish and Also Using the GBO 20m Dish
Tutorial Presentation
Drift Scan Data Analysis User Guide
GB 20 Meter Data Analysis User Guide
Drift Scan Data Analysis Template
GB 20 Meter Data Analysis Template
Data Template
You can download the data template at this location.
Useful Links
• Radio Observing Award Programs
• Citizen Science Radio Astronomy Award Programs
• Links (including related topics in the SARA Listserv Archive, and SARA Journal Table of Contents)
• References
• Glossary: http://www.radio-astronomy.org/pdf/SARA%20Glossary.pdf
• edX Radio Astronomy Certificate Course
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SARA is dedicated to the exploration of radio astronomy at the amateur level. Many amateurs are engaged in developing hardware, software, and methodologies to expand the limits of amateur radio observation. Such amateurs impose intriguing opportunities. With peer review, they can develop new approaches to radio astronomy observation, or offer an equally valuable dissertation on explanations to misidentified radio observations and their nature. SARA welcomes positive diversity of opinion but does not necessarily embrace those opinions as it own.