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J. DaÂngela,
T. Shanks,
S. M. Croom,
P. Weilbacher,
R. J. Brunner,
W. J. Couch,
L. Miller,
A. D. Myers,
R. C. Nichol,
K. A. Pimbblet,
R. De Propris,
G. T. Richards,
N. P. Ross,
D. P. Schneider, D. Wake
[show abstract]
[hide abstract]
ABSTRACT: We combine the quasi-stellar object (QSO) samples from the 2dF QSO Redshift Survey (2QZ) and the 2dF-Sloan Digital Sky Survey luminous red galaxy (LRG) and QSO Survey (2dF-SDSS LRG and QSO, hereafter 2SLAQ) in order to investigate the clustering of z∼ 1.5 QSOs and measure the correlation function (ξ). The clustering signal in redshift-space and projected along the sky direction is similar to that previously obtained from the 2QZ sample alone. By fitting functional forms for ξ(σ, π), the correlation function measured along and across the line of sight, we find, as expected, that β, the dynamical infall parameter and Ω0m, the cosmological density parameter, are degenerate. However, this degeneracy can be lifted by using linear theory predictions under different cosmological scenarios. Using the combination of the 2QZ and 2SLAQ QSO data, we obtain: βQSO(z= 1.5) = 0.60+0.14−0.11, Ω0m= 0.25+0.09−0.07 which imply a value for the QSO bias, b(z= 1.4) = 1.5 ± 0.2.The combination of the 2QZ with the fainter 2SLAQ QSO sample further reveals that QSO clustering does not depend strongly on luminosity at fixed redshift. This result is inconsistent with the expectation of simple ‘high peaks’ biasing models where more luminous, rare QSOs are assumed to inhabit higher mass haloes. The data are more consistent with models which predict that QSOs of different luminosities reside in haloes of similar mass. By assuming ellipsoidal models for the collapse of density perturbations, we estimate the mass of the dark matter haloes which the QSOs inhabit as ∼3 × 1012 h−1 M⊙. We find that this halo mass does not evolve strongly with redshift nor depend on QSO luminosity. Assuming a range of relations which relate halo to black hole mass, we investigate how black hole mass correlates with luminosity and redshift, and ascertain the relation between Eddington efficiency and black hole mass. Our results suggest that QSOs of different luminosities may contain black holes of similar mass.
Monthly Notices of the Royal Astronomical Society 01/2008; 383(2):565 - 580. · 4.90 Impact Factor
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R. Cannon,
M. Drinkwater,
A. Edge,
D. Eisenstein,
R. Nichol,
P. Outram,
K. Pimbblet,
R. de Propris,
I. Roseboom, D. Wake, [......],
N. Ross,
E. M. Sadler,
T. Shanks,
R. Sharp,
J. A. Smith,
C. Stoughton,
P. Weilbacher,
R. J. Brunner,
A. Meiksin,
D. P. Schneider
[show abstract]
[hide abstract]
ABSTRACT: This version of the catalogue was created as v5.1 on 01 Feb 2006 by
Russell Cannon. Essentially the same data were used in the other 2SLAQ
LRG papers written in 2006.
There is one line for each object observed, sorted by RA. The best
available redshift, i.e. the one with the highest reliability parameter
Q (or the higher S/N in the case of a tie), is given for objects with
two or more observations. Another version of the listing, including
repeats, is available from the UQ web site at
http://lrg.physics.uq.edu.au.
The first 27 columns come from the AAO redshifting code (i.e. the
concatenated *z.rz output lists from RDC's version of Will Sutherland's
original Zcode). Columns 28 to 35 are from the SDSS input target lists
prepared by Daniel Eisenstein. Column 36 contains any notes made during
the redshifting or subsequent analysis.
The first 34 columns are present for all targets, in a fixed format with
leading zeroes where appropriate so that they can be easily read in free
format. Column 35 gives the original SDSS run_camcol object names for
the 2003 2dF data only and is blank otherwise.
Note that this version of the redshift listing uses SDSS DR4 photometry
in col. 8 and cols. 31-34 (for all but 10 objects) but retains the
original DR1 SDSS positions (as used by 2dF) in cols. 28 and 29. Earlier
listings up to and including v4 (available from RDC) gave the DR1
photometry used for 2dF target selection; the differences are very small
for >99% of the targets.
(1 data file).
VizieR Online Data Catalog. 05/2007; 837:20425.
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A. Collister,
O. Lahav,
C Blake,
Russell Cannon,
Scott Croom,
M. J. Drinkwater,
A. Edge,
D. Eisenstein,
J. Loveday,
R. Nichol,
K. A. Pimbblet,
R. De Propris,
I. Roseboom,
Nic Ross,
D. P. Schneider,
T. Shanks, D. Wake
[show abstract]
[hide abstract]
ABSTRACT: We describe the construction of MegaZ-LRG, a photometric redshift catalogue of over one million luminous red galaxies (LRGs) in the redshift range 0.4 < z < 0.7 with limiting magnitude i < 20. The catalogue is selected from the imaging data of the Sloan Digital Sky Survey (SDSS) Data Release 4. The 2dF-SDSS LRG and Quasar (2SLAQ) spectroscopic redshift catalogue of 13 000 intermediate-redshift LRGs provides a photometric redshift training set, allowing use of annz, a neural network-based photometric-redshift estimator. The rms photometric redshift accuracy obtained for an evaluation set selected from the 2SLAQ sample is sigma(z) 0.049 averaged over all galaxies, and sigma(z) = 0.040 for a brighter subsample (i < 19.0). The catalogue is expected to contain similar to 5 per cent stellar contamination. The annz code is used to compute a refined star/galaxy probability based on a range of photometric parameters; this allows the contamination fraction to be reduced to 2 per cent with negligible loss of genuine galaxies. The MegaZ-LRG catalogue is publicly available on the World Wide Web from http://www.2slaq.info.
08/2006;
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D. Wake,
R. Nichol,
D. J. Eisenstein,
J. Loveday,
A. C. Edge,
R. Cannon,
I. Smail,
D. P. Schneider,
R. Scranton,
D. Carson,
M. J. Drinkwater,
K. A. Pimbblet,
I. G. Roseboom
[show abstract]
[hide abstract]
ABSTRACT: We present new measurements of the luminosity function (LF) of luminous red galaxies (LRGs) from the Sloan Digital Sky Survey (SDSS) and the 2dF SDSS LRG and Quasar (2SLAQ) survey. We have carefully quantified, and corrected for, uncertainties in the K and evolutionary corrections, differences in the colour selection methods, and the effects of photometric errors, thus ensuring we are studying the same galaxy population in both surveys. Using a limited subset of 6326 SDSS LRGs (with 0.17 < z < 0.24) and 1725 2SLAQ LRGs (with 0.5 < z < 0.6), for which the matching colour selection is most reliable, we find no evidence for any additional evolution in the LRG LF, over this redshift range, beyond that expected from a simple passive evolution model. This lack of additional evolution is quantified using the comoving luminosity density of SDSS and 2SLAQ LRGs, brighter than M-0.2r - 5 log h(0.7) = - 22.5, which are 2.51 +/- 0.03 x 10(-7) L circle dot Mpc(-3) and 2.44 +/- 0.15 x 10(-7) L circle dot Mpc(-3), respectively (< 10 per cent uncertainty). We compare our LFs to the COMBO-17 data and find excellent agreement over the same redshift range. Together, these surveys show no evidence for additional evolution (beyond passive) in the LF of LRGs brighter than M-0.2r - 5 log h(0.7) = - 21 ( or brighter than similar to L-*).. We test our SDSS and 2SLAQ LFs against a simple 'dry merger' model for the evolution of massive red galaxies and find that at least half of the LRGs at z similar or equal to 0.2 must already have been well assembled (with more than half their stellar mass) by z similar or equal to 0.6. This limit is barely consistent with recent results from semi-analytical models of galaxy evolution.
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R. Cannon,
M. Drinkwater,
A. Edge,
D. Eisenstein,
R. Nichol,
P. Outram,
K. Pimbblet,
R. De Propris,
I. Roseboom, D. Wake, [......],
N. Ross,
E. M. Sadler,
T. Shanks,
R. Sharp,
J A Smith,
C. Stoughton,
P. Weilbacher,
R. J. Brunner,
A. Meiksin,
D. P. Schneider
[show abstract]
[hide abstract]
ABSTRACT: We present a spectroscopic survey of almost 15 000 candidate intermediate-redshift luminous red galaxies (LRGs) brighter than i = 19.8, observed with 2dF on the Anglo-Australian Telescope. The targets were selected photometrically from the Sloan Digital Sky Survey (SDSS) and lie along two narrow equatorial strips covering 180 deg(2). Reliable redshifts were obtained for 92 per cent of the targets and the selection is very efficient: over 90 per cent have 0.45 < z < 0.8. More than 80 per cent of the similar to 11 000 red galaxies have pure absorption-line spectra consistent with a passively evolving old stellar population. The redshift, photometric and spatial distributions of the LRGs are described. The 2SLAQ data will be released publicly from mid-2006, providing a powerful resource for observational cosmology and the study of galaxy evolution.
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J. da Angela,
T. Shanks,
S. M. Croom,
P. Weilbacher,
R. J. Brunner,
W. J. Couch,
L Miller,
A. D. Myers,
R. C. Nichol,
K. A. Pimbblet,
R. De Propris,
G. T. Richards,
N. P. Ross,
D. P. Schneider, D. Wake
[show abstract]
[hide abstract]
ABSTRACT: We combine the quasi-stellar object (QSO) samples from the 2dF QSO Redshift Survey (2QZ) and the 2dF-Sloan Digital Sky Survey luminous red galaxy (LRG) and QSO Survey (2dF-SDSS LRG and QSO, hereafter 2SLAQ) in order to investigate the clustering of z∼ 1.5 QSOs and measure the correlation function (ξ). The clustering signal in redshift-space and projected along the sky direction is similar to that previously obtained from the 2QZ sample alone. By fitting functional forms for ξ(σ, π), the correlation function measured along and across the line of sight, we find, as expected, that β, the dynamical infall parameter and Ω0m , the cosmological density parameter, are degenerate. However, this degeneracy can be lifted by using linear theory predictions under different cosmological scenarios. Using the combination of the 2QZ and 2SLAQ QSO data, we obtain: βQSO(z= 1.5) = 0.60+0.14−0.11, Ω0m= 0.25+0.09−0.07 which imply a value for the QSO bias, b(z= 1.4) = 1.5 ± 0.2 . The combination of the 2QZ with the fainter 2SLAQ QSO sample further reveals that QSO clustering does not depend strongly on luminosity at fixed redshift. This result is inconsistent with the expectation of simple 'high peaks' biasing models where more luminous, rare QSOs are assumed to inhabit higher mass haloes. The data are more consistent with models which predict that QSOs of different luminosities reside in haloes of similar mass. By assuming ellipsoidal models for the collapse of density perturbations, we estimate the mass of the dark matter haloes which the QSOs inhabit as ∼3 × 1012 h−1 M⊙ . We find that this halo mass does not evolve strongly with redshift nor depend on QSO luminosity. Assuming a range of relations which relate halo to black hole mass, we investigate how black hole mass correlates with luminosity and redshift, and ascertain the relation between Eddington efficiency and black hole mass. Our results suggest that QSOs of different luminosities may contain black holes of similar mass.
-
[show abstract]
[hide abstract]
ABSTRACT: This paper describes the application of atmospheric pressure MOVPE to the growth of several long wavelength opto-electronic components including lasers, detectors, field effect transistors and guided wave devices. Particular emphasis is placed on aspects of the growth technique which lead to improved performance or fabrication of the devices. State of the art operating characteristics measured for all the devices described in the paper illustrates the powerful capabilities of the atmospheric pressure MOVPE technique for the high yield production of a wide range of high performance opto-electronic components.
Journal of Crystal Growth.
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[show abstract]
[hide abstract]
ABSTRACT: Triboelectric exchange of charge between dissimilar polymers on contact can be used to good effect in the construction of air filters because the electric charge on the constituent fibres of filters made in this way attracts dust particles. A study of the sign, magnitude, and lifetime of the charge on such filters has been made, though the methods of investigation are, of necessity, indirect. It has been possible to measure the magnitude of the charge on complete filters only by neutralising the charge with measured doses of ionising radiation. Changes in the charged state of a filter can, likewise, only be measured by the effects that they produce on filtration efficiency. Measurements using yarns of the constituent fibres aid our understanding of the charging process, but the lifetime of charge on the yarns is quite different from that on the filter fibres. Results are given of the filtration performance of an optimal mixture, the electric charge on which results in a high filtration efficiency for submicron particles.
Journal of Electrostatics.
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[show abstract]
[hide abstract]
ABSTRACT: Respirator filters and filtering facepieces have been tested for filtration efficiency against radon daughters in a flourspar mine. The test method involved the use of sampling filters exposed to natural radon daughters in air filtered by the test respirators. Respirators with a filtration efficiency high enough for them to be considered suitable for use against toxic dusts generally reduced radon daughter levels by 90% or more, though nuisance dust masks were ineffective. The measured penetration of radon daughters through the former types of filter correlated reasonably well with the penetration of 0.1μm neutralised monodisperse aerosol and with that of the BS4400 sodium chloride aerosol, measured in the laboratory. Test filters were exposed to radon daughters in the mine for 8 hours as a simulation of their behaviour during a working shift, but their performance was not altered by this and they did not show measurable radioactivity as a result of it.
Journal of Aerosol Science.
