Many recently discovered dwarf galaxies, especially those seen in systematic photometric surveys such as the Sloan Digital Sky Survey (SDSS) and the Dark Energy Survey (DES) are very faint with absolute luminosity in the optical waveband below -8 magnitude. (sciencedaily.com)
Abigail Sellen and Mik Lamming of Rank Xerox in Cambridge are building pager - like devices that communicate in the infrared waveband with other transmitters, receivers and communication devices. (newscientist.com)
Aliens wishing to communicate would probably broadcast at frequencies between 1 and 10 gigahertz, where there's less astronomical background noise than in other wavebands. (newscientist.com)