Glossary of Radio Astronomy Terms
Transporter:
The two VLA transporters are special-purpose vehicles designed specifically to pick up and carry the VLA’s 230-ton dish antennas. The transporters run on two parallel sets of U.S. gauge railroad tracks — four rails in total. Weighing 90 tons themselves, the transporters are powered by 380- and 400-horsepower (respectively) diesel engines that in turn power a hydraulic system. That system drives the wheels using radial hydraulic motors and also powers the jacks that lift the antennas off their concrete-pier mountings. The wheels are mounted on assemblies at each corner of the vehicle that can rotate to allow “turning” the 90-degree rail intersections that connect each antenna mounting station with the main rail line for each arm of the VLA’s “Y” layout.
![Transporter](https://public.nrao.edu/wp-content/uploads/2013/09/gallery-images-largeVLAtransportersidedishes2_large-150x150.jpg)
T Tauri Stars:
Young stars surrounded by gas and dust; believed to be contracting to main sequence stars.
![T Tauri Stars](https://public.nrao.edu/wp-content/uploads/2014/09/imagesnon-gallery2014c-blue09-22-ALMA-T-TauriTTauri_nrao-150x150.jpg)
Thermal emission:
Radiation emitted due to an object’s temperature or ionized gas
Tidal disruption event:
When a star being destroyed by a supermassive black hole is pulled apart and emits powerful jets of material along with light.
![Tidal disruption event](https://public.nrao.edu/wp-content/uploads/2018/06/nrao18df04_artistfinal-150x150.jpg)
Transit:
The passage of a celestial body across an observer’s meridian; also the passage of a celestial body across the disk of a larger one.
Telescope:
An instrument used to collect electromagnetic radiation (e.g. radio waves) from distant objects and enable direct observation.
![Telescope](https://public.nrao.edu/wp-content/uploads/2011/10/imagessquared2011CenterofALMA_Burchell11-150x150.jpg)
Torus:
The donut-shaped feature of dust and gas that surrounds some supermassive black holes.
![Torus](https://public.nrao.edu/wp-content/uploads/2015/04/imagesnon-gallery2015c-blue04-15-Black-HoleESO-SMB_nrao-150x150.jpg)