Browsing by Author "Simpson, Chris"
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Item Evolution of star formation in the UKIDSS ultra deep survey field - I. Luminosity functions and cosmic star formation rate out of z = 1.6(OUP, 2013) Drake, Alyssa B.; Simpson, Chris; Collins, Chris A.; Jarvis, MattWe present new results on the cosmic star formation history in the SXDS-UDS field out to z = 1.6. We compile narrow-band data from the Subaru Telescope and the Visible and Infrared Survey Telescope for Astronomy (VISTA) in conjunction with broad-band data from the SXDS and UDS, to make a selection of 5725 emission-line galaxies in 12 redshift slices, spanning 10 Gyr of cosmic time. We determine photometric redshifts for the sample using 11-band photometry, and use a spectroscopically confirmed subset to fine tune the resultant redshift distribution.We use themaximum-likelihood technique to determine luminosity functions in each redshift slice and model the selection effects inherent in any narrow-band selection statistically, to obviate the retrospective corrections ordinarily required. The deep narrow band data are sensitive to very low star formation rates (SFRs), and allow an accurate evaluation of the faint end slope of the Schechter function, α.We find that α is particularly sensitive to the assumed faintest broadband magnitude of a galaxy capable of hosting an emission line, and propose that this limit should be empirically motivated. For this analysis we base our threshold on the limiting observed equivalent widths of emission lines in the local Universe. We compute the characteristic SFR of galaxies in each redshift slice, and the integrated SFR density, ρSFR. We find our results to be in good agreement with the literature and parametrize the evolution of the SFR density as ρSFR (1 + z)4.58 confirming a steep decline in star formation activity since z ~ 1.6Item The VISTA Deep Extragalactic Observations (VIDEO) survey(Oxford University Press, 2013) Jarvis, Matt; Bonfield, David G.; Bruce, V.A.; Zwart, J.; Geach, J.E.; McAlpine, K.; McLure, R.J.; Gonzalez-Solares, Eduardo A.; Irwin, M.; Lewis, J.; Kupcu Yoldas, A.; Andreon, S.; Cross, N.J.G.; Emerson, J.P.; Dalton, G.; Dunlop, J.S.; Hodgkin, S. T.; Le Fevre, O.; Karouzos, M.; Meisenheimer, K.; Oliver, S.; Rawlings, S.; Simpson, Chris; Smail, I.; Smith, Daniel J.B.; Sullivan, M.; Sutherland, W.; White, S.V.In this paper we describe the first data release of the the Visible and Infrared Survey Telescope for Astronomy (VISTA) Deep Extragalactic Observations (VIDEO) survey. VIDEO is a 12 degree2 survey in the near-infrared Z,Y ,J,H andKs bands, specifically designed to enable the evolution of galaxies and large structures to be traced as a function of both epoch and environment from the present day out to z=4, and active galactic nuclei (AGN) and the most massive galaxies up to and into the epoch of reionization. With its depth and area, VIDEO will be able to fully explore the period in the Universe where AGN and starburst activity were at their peak and the first galaxy clusters were beginning to virialize. VIDEO therefore offers a unique data set with which to investigate the interplay between AGN, starbursts and environment, and the role of feedback at a time when it was potentially most crucial. We provide data over the VIDEO-XMM3 tile, which also covers the Canada-France- Hawaii-Telescope Legacy Survey Deep-1 field (CFHTLS-D1). The released VIDEO data reach a 5 AB-magnitude depth of Z = 25:7, Y = 24:5, J = 24:4, H = 24:1 and Ks = 23:8 in 2 arcsec diameter apertures (the full depth of Y = 24:6 will be reached within the full integration time in future releases). The data are compared to previous surveys over this field and we find good astrometric agreement with the Two-Micron All Sky Survey, and source counts in agreement with the recently released UltraVISTA survey data. The addition of the VIDEO data to the CFHTLS-D1 optical data increases the accuracy of photometric redshifts and significantly reduces the fraction of catastrophic outliers over the redshift range 0 < z < 1 from 5.8 to 3.1 per cent in the absence of an iband luminosity prior. However, we expect the main improvement in photometric redshifts will come in the redshift range 1 < z < 4 due to the sensitivity to the Balmer and 4000°A breaks provided by the near-infrared VISTA filters. All images and catalogues presented in this paper are publicly available through ESO’s phase 3 archive and the VISTA Science Archive.