| dc.description.abstract | We used data from the Visible and Infrared Survey Telescope for Astronomy Deep Extragalactic
Observations (VIDEO) Survey and from the Spitzer Extragalactic Representative Survey
(SERVS) to generate a sample of Extremely Red Galaxies (ERGs) with colours H - [4:5] > 4,
by matching H-band (with a bandpass centred on 1:65mm) near-infrared data, and 4:5mm midinfrared
data. Using optical data from the Canada-France-Hawaii Telescope Legacy Survey
(CFHTLS) and a pre-release of data from the European Southern Observatory Spitzer Imaging
Extragalactic Survey (ESIS), extra wavelength bands covering each of the sources in our sample
was assembled to increase the wavelengths available. Through the use of Le Phare, a photometric
redshift, spectral energy distribution, fitting code, we calculated the probabilities of many
different models across a range of redshifts (z) and extinctions (AV ) for these sources, along
with what type of model, be it QSO or Galaxy, was the best fit for them. The sample constructed
was ~ 3:75 magnitudes brighter than the ERGs previously explored in previous work by Caputi
et al. (2012) and were at lower redshifts (0:4 < z < 3:0). The sample was also found to be primarily
modelled by QSO templates. Using data from the Herschel Multi-tiered Extragalactic
Survey (HerMES), a far-infrared survey, and assuming a specific dust template model, we converted
the 250mm fluxes to a total infrared luminosity, and then used a standard calibration to
convert this to the Star Formation Rate (SFR) for each source. These SFRs were very variable,
with one source at ~ 0 M_yr-1 and one even greater than 1000 M_yr-1. We used all of this
information to determine the probabilities of each possibility, and their reliability. We also discussed
the best fit solutions and if we can trust them, including the importance of the optical data
for deriving reliable source properties. We then related our sample of sources to similar ERGs
in the literature before finishing with a simulation calculation to estimate how many galaxies
with our chosen colour we would expect to see in the area of sky investigated. It was found that
current semi-analytical models such as Henriques’ work, based on the Millenium Simulation
(Henriques et al., 2009), predicts an ERG density ~ 54 times less than that found in this work.
Finally we discuss a potential for follow up work, including different SED fitting techniques, an
extra sample of templates, and spectroscopic follow-up. | en_US |
