We present the results of a pilot survey to find dust-reddened quasars by matching the FIRST radio catalog to the UKIDSS near-infrared survey, and using optical data from SDSS to select objects with ...very red colors. The deep K-band limit provided by UKIDSS allows for finding more heavily-reddened quasars at higher redshifts as compared with previous work using FIRST and 2MASS. We selected 87 candidates with K<=17.0 from the UKIDSS Large Area Survey (LAS) First Data Release (DR1) which covers 190 deg2. These candidates reach up to ~1.5 magnitudes below the 2MASS limit and obey the color criteria developed to identify dust-reddened quasars. We have obtained 61 spectroscopic observations in the optical and/or near-infrared as well as classifications in the literature and have identified 14 reddened quasars with E(B-V)>0.1, including three at z>2. We study the infrared properties of the sample using photometry from the WISE Observatory and find that infrared colors improve the efficiency of red quasar selection, removing many contaminants in an infrared-to-optical color-selected sample alone. The highest-redshift quasars (z > 2) are only moderately reddened, with E(B-V) ~ 0.2-0.3. We find that the surface density of red quasars rises sharply with faintness, comprising up to 17% of blue quasars at the same apparent K-band flux limit. We estimate that to reach more heavily reddened quasars (i.e., E(B-V) > 0.5) at z>2 and a depth of K=17 we would need to survey at least ~2.5 times more area.
We present the GAMA Panchromatic Data Release (PDR) constituting over 230deg\(^2\) of imaging with photometry in 21 bands extending from the far-UV to the far-IR. These data complement our ...spectroscopic campaign of over 300k galaxies, and are compiled from observations with a variety of facilities including: GALEX, SDSS, VISTA, WISE, and Herschel, with the GAMA regions currently being surveyed by VST and scheduled for observations by ASKAP. These data are processed to a common astrometric solution, from which photometry is derived for 221,373 galaxies with r<19.8 mag. Online tools are provided to access and download data cutouts, or the full mosaics of the GAMA regions in each band. We focus, in particular, on the reduction and analysis of the VISTA VIKING data, and compare to earlier datasets (i.e., 2MASS and UKIDSS) before combining the data and examining its integrity. Having derived the 21-band photometric catalogue we proceed to fit the data using the energy balance code MAGPHYS. These measurements are then used to obtain the first fully empirical measurement of the 0.1-500\(\mu\)m energy output of the Universe. Exploring the Cosmic Spectral Energy Distribution (CSED) across three time-intervals (0.3-1.1Gyr, 1.1-1.8~Gyr and 1.8---2.4~Gyr), we find that the Universe is currently generating \((1.5 \pm 0.3) \times 10^{35}\) h\(_{70}\) W Mpc\(^{-3}\), down from \((2.5 \pm 0.2) \times 10^{35}\) h\(_{70}\) W Mpc\(^{-3}\) 2.3~Gyr ago. More importantly, we identify significant and smooth evolution in the integrated photon escape fraction at all wavelengths, with the UV escape fraction increasing from 27(18)% at z=0.18 in NUV(FUV) to 34(23)% at z=0.06. The GAMA PDR will allow for detailed studies of the energy production and outputs of individual systems, sub-populations, and representative galaxy samples at \(z<0.5\). The GAMA PDR can be found at: http://gama-psi.icrar.org/
In order to generate credible 0.1-2 {\mu}m SEDs, the GAMA project requires
many Gigabytes of imaging data from a number of instruments to be re-processed
into a standard format. In this paper we ...discuss the software infrastructure we
use, and create self-consistent ugrizYJHK photometry for all sources within the
GAMA sample. Using UKIDSS and SDSS archive data, we outline the pre-processing
necessary to standardise all images to a common zeropoint, the steps taken to
correct for seeing bias across the dataset, and the creation of Gigapixel-scale
mosaics of the three 4x12 deg GAMA regions in each filter. From these mosaics,
we extract source catalogues for the GAMA regions using elliptical Kron and
Petrosian matched apertures. We also calculate S\'ersic magnitudes for all
galaxies within the GAMA sample using SIGMA, a galaxy component modelling
wrapper for GALFIT 3. We compare the resultant photometry directly, and also
calculate the r band galaxy LF for all photometric datasets to highlight the
uncertainty introduced by the photometric method. We find that (1) Changing the
object detection threshold has a minor effect on the best-fitting Schechter
parameters of the overall population (M* +/- 0.055mag, {\alpha} +/- 0.014,
{\Phi}* +/- 0.0005 h^3 Mpc^{-3}). (2) An offset between datasets that use Kron
or Petrosian photometry regardless of the filter. (3) The decision to use
circular or elliptical apertures causes an offset in M* of 0.20mag. (4) The
best-fitting Schechter parameters from total-magnitude photometric systems
(such as SDSS modelmag or S\'ersic magnitudes) have a steeper faint-end slope
than photometry dependent on Kron or Petrosian magnitudes. (5) Our Universe's
total luminosity density, when calculated using Kron or Petrosian r-band
photometry, is underestimated by at least 15%.
The Galaxy And Mass Assembly (GAMA) project is the latest in a tradition of large galaxy redshift surveys, and is now underway on the 3.9m Anglo-Australian Telescope at Siding Spring Observatory. ...GAMA is designed to map extragalactic structures on scales of 1kpc - 1Mpc in complete detail to a redshift of z~0.2, and to trace the distribution of luminous galaxies out to z~0.5. The principal science aim is to test the standard hierarchical structure formation paradigm of Cold Dark Matter (CDM) on scales of galaxy groups, pairs, discs, bulges and bars. We will measure (1) the Dark Matter Halo Mass Function (as inferred from galaxy group velocity dispersions); (2) baryonic processes, such as star formation and galaxy formation efficiency (as derived from Galaxy Stellar Mass Functions); and (3) the evolution of galaxy merger rates (via galaxy close pairs and galaxy asymmetries). Additionally, GAMA will form the central part of a new galaxy database, which aims to contain 275,000 galaxies with multi-wavelength coverage from coordinated observations with the latest international ground- and space-based facilities: GALEX, VST, VISTA, WISE, HERSCHEL, GMRT and ASKAP. Together, these data will provide increased depth (over 2 magnitudes), doubled spatial resolution (0.7"), and significantly extended wavelength coverage (UV through Far-IR to radio) over the main SDSS spectroscopic survey for five regions, each of around 50 deg^2. This database will permit detailed investigations of the structural, chemical, and dynamical properties of all galaxy types, across all environments, and over a 5 billion year timeline.
In order to generate credible 0.1-2 {\mu}m SEDs, the GAMA project requires many Gigabytes of imaging data from a number of instruments to be re-processed into a standard format. In this paper we ...discuss the software infrastructure we use, and create self-consistent ugrizYJHK photometry for all sources within the GAMA sample. Using UKIDSS and SDSS archive data, we outline the pre-processing necessary to standardise all images to a common zeropoint, the steps taken to correct for seeing bias across the dataset, and the creation of Gigapixel-scale mosaics of the three 4x12 deg GAMA regions in each filter. From these mosaics, we extract source catalogues for the GAMA regions using elliptical Kron and Petrosian matched apertures. We also calculate Sérsic magnitudes for all galaxies within the GAMA sample using SIGMA, a galaxy component modelling wrapper for GALFIT 3. We compare the resultant photometry directly, and also calculate the r band galaxy LF for all photometric datasets to highlight the uncertainty introduced by the photometric method. We find that (1) Changing the object detection threshold has a minor effect on the best-fitting Schechter parameters of the overall population (M* +/- 0.055mag, {\alpha} +/- 0.014, {\Phi}* +/- 0.0005 h^3 Mpc^{-3}). (2) An offset between datasets that use Kron or Petrosian photometry regardless of the filter. (3) The decision to use circular or elliptical apertures causes an offset in M* of 0.20mag. (4) The best-fitting Schechter parameters from total-magnitude photometric systems (such as SDSS modelmag or Sérsic magnitudes) have a steeper faint-end slope than photometry dependent on Kron or Petrosian magnitudes. (5) Our Universe's total luminosity density, when calculated using Kron or Petrosian r-band photometry, is underestimated by at least 15%.
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