Studying the Extragalactic Background Light with the Second Cosmic Infrared Background ExpeRiment, CIBER-2

Fluctuations in the extragalactic background light trace emission from the entire history of galaxy formation, including emission from early luminous sources prior to the reionization of the universe. The formation of the first luminous objects represents an important transition in the evolution of the universe from its smooth initial state to the clumpy, highly ordered state observable today. However, these objects are faint and diffuse and not well studied; direct observations of their emission are needed to constrain current numerical simulations of the nonlinear evolution of the early universe. A number of recent near-infrared measurements show excess spatial power at large angular scales inconsistent with models of z &#60; 5 emission from galaxies. These measurements have been interpreted as arising from either redshifted emission of early luminous objects, such as stellar and quasar emission from the epoch of reionization, or the combined intra-halo light from stars thrown out of more recent galaxies during merging activity at lower redshifts. Though astrophysically distinct, both interpretations arise from faint, low surface brightness source populations that are difficult to detect except by statistical approaches using careful observations with suitable instruments. The key to determining the source of these background anisotropies will be wide-field imaging measurements spanning multiple bands from the optical to the near-infrared. The Cosmic Infrared Background ExpeRiment 2 (CIBER-2) will measure spatial anisotropies in the extragalactic infrared background caused by cosmological structure using six broad spectral bands. The experiment uses three 2048 x 2048 Hawaii-2RG near-infrared arrays in three cameras coupled to a single 28.5 cm telescope housed in a reusable sounding rocket-borne payload. A small portion of each array will also be combined with a linear-variable filter to make absolute measurements of the spectrum of the extragalactic background with high spatial resolution for deep subtraction of Galactic starlight. The large field of view and multiple spectral bands make CIBER-2 unique in its sensitivity to fluctuations predicted by models of lower limits on the luminosity of the first stars and galaxies and in its ability to distinguish between primordial and foreground anisotropies. This work encompasses the scientific motivation for CIBER-2 and describes details of the instrument design and verification prior to flight.</p