Great Surveys of the Universe

When, and how, did the first galaxies and supermassive black holes (SMBH) form, and how did they reionization the Universe? First galaxy formation and cosmic reionization are among the last frontiers in studies of cosmic structure formation. We delineate the detailed astrophysical probes of early galaxy and SMBH formation afforded by observations at centimeter through submillimeter wavelengths. These observations include studies of the molecular gas (= the fuel for star formation in galaxies), atomic fine structure lines (= the dominant ISM gas coolant), thermal dust continuum emission (= an ideal star formation rate estimator), and radio continuum emission from star formation and relativistic jets. High resolution spectroscopic imaging can be used to study galaxy dynamics and star formation on sub-kpc scales. These cm and mm observations are the necessary compliment to near-IR observations, which probe the stars and ionized gas, and X-ray observations, which reveal the AGN. Together, a suite of revolutionary observatories planned for the next decade from centimeter to X-ray wavelengths will provide the requisite panchromatic view of the complex processes involved in the formation of the first generation of galaxies and SMBHs, and cosmic reionization. 1 The formation of the first galaxies and SMBH Study of the formation of the first galaxies and super-massive black holes is a key science driver for essentially all large area telescopes, at all wavelengths, under construction or design. Deep near-IR surveys have revolutionized our understanding of early galaxy formation by revealing star forming galaxies and SMBH back to the near-edge of cosmic reionization, z ∼ 6 to 7 (Ellis 2007, Saas Fe Advanced Course 36 astroph/070124; Fan et al. 2006, ARAA, 44, 414). Reionization sets a fundamental benchmark in cosmic structure formation, corresponding to the epoch when the first luminous sources (galaxies, quasars) reionize the neutral IGM. Current cm and mm facilities are providing the first glimpse into the cool gas, dust, and (obscuration-free) star formation in very early (massive) galaxies. In this white paper we describe the key contributions that will be made in the next decade to the detailed study of the first galaxies and SMBH with the powerful suite of large centimeter (cm) and millimeter (mm) interferometers and single dish telescopes. We delineate a key science program on first galaxy formation involving observations from cm through near-IR wavelengths, along with the instrumentation development for the cm and mm facilities that will leverage the major infrastructure investment for dramatic science return. 2 Probing the era of first galaxies While progress in the field of very high z galaxy formation has been impressive, near-IR studies of the earliest galaxies are fundamentally limited in two ways: (i) obscuration of rest-frame UV emission by dust, and Lyα scattering in the neutral intergalactic medium, may lead to a biased view of galaxy formation, and (ii) near-IR studies reveal only the stars and ionized gas, thereby missing the evolution of the cool gas in galaxies, the fuel for star formation. Line and continuum studies in the centimeter (cm) and millimeter (mm) and