Lyman-alpha emitters are thought to be young, low-mass galaxies with ages of approximately 10(8) yr (refs 1, 2). An overdensity of them in one region of the sky (the SSA 22 field) traces out a filamentary structure in the early Universe at a redshift of z approximately 3.1 (equivalent to 15 per cent of the age of the Universe) and is believed to mark a forming protocluster.
View Article and Find Full Text PDFSubmillimetre surveys during the past decade have discovered a population of luminous, high-redshift, dusty starburst galaxies. In the redshift range 1