21-M Space Tracking Antenna

The instrument is a unique educational tool that provides an active laboratory for students to have hands-on learning experiences with the intricacies of satellite telecommunications and radio astronomy. The 21-M supports undergraduate research in astrophysics, satellite telecommunications, RF and electrical engineering and software development. The 21-M antenna system became operational in 2006 and is currently engaged in radio astronomy research. The 21-M antenna also serves as the primary Earth station for the KySat series of satellites.

Radio astronomy research projects include:

• Long-term monitoring campaigns (AGNs)
• Sky surveys (Dynamic Mapping of HI in the Milky Way)
• Transient phenomena (radio afterglow of GRBs)

The 21-M is considered to be a medium-aperture telescope where apertures of radio telescopes have been generally categorized by a ratio of the aperture diameter to the incident wavelength. At L-Band, the ratio of the aperture diameter of the Antenna to the incident wavelength exceeds 100 while at higher frequencies this ratio becomes 1000 or higher. Medium-aperture telescopes such as the Antenna have many advantages as active laboratories and as research instruments for both students and faculty members. Medium-aperture centimeter-wave instruments like the Antenna can produce significant scientific contributions: for example, while time on large-aperture instruments is generally heavily subscribed for phenomenon-specific observations, medium-aperture telescopes can devote time to long-term monitoring campaigns, sky surveys, and event-specific phenomena such as supernovae, gamma-ray bursts and apparitions of comets. In this respect, the Antenna stands to produce a lasting legacy of crucial datasets at multiple frequencies for the entire astronomical community.

Maps of the spatial distribution of RF emission associated with astronomical objects are produced by raster scanning across the field of view and producing a map of the RF intensity distribution field by integrating the entire post-detection frequency band of 6 MHz into a single, integrated channel map (0th-moment map). An image of the velocity field (1st-moment map) and an image of the velocity dispersion (2nd-moment map) can also be produced. Analysis of these maps of the phenomena in "velocity space" allows astronomers to calculate the kinematics of the system and thereby derive the dynamics, then infer the energetics, and virial masses, along with other insights into the underlying physics of these systems. An example of a 0th-moment map showing the spatial distribution of radio emission from a supernova remnant (3C 157) is shown (left center). The detail seen in this image demonstrates the sensitivity and resolution of the 21-M.