1,895 research outputs found
A structure in the early Universe at z 1.3 that exceeds the homogeneity scale of the R-W concordance cosmology
A Large Quasar Group (LQG) of particularly large size and high membership has been identified in the DR7QSO catalogue of the Sloan Digital Sky Survey. It has characteristic size (volume^1/3) ~ 500 Mpc (proper size, present epoch), longest dimension ~ 1240 Mpc, membership of 73 quasars, and mean redshift = 1.27. In terms of both size and membership it is the most extreme LQG found in the DR7QSO catalogue for the redshift range 1.0 = 1.28, which is itself one of the more extreme examples. Their boundaries approach to within ~ 2 deg (~ 140 Mpc projected). This new, huge LQG appears to be the largest structure currently known in the early universe. Its size suggests incompatibility with the Yadav et al. scale of homogeneity for the concordance cosmology, and thus challenges the assumption of the cosmological principle
Searching High Redshift Large-Scale Structures: Photometry of Four Fields Around Quasar Pairs at z~1
We have studied the photometric properties of four fields around the
high-redshift quasar pairs QP1310+0007, QP1355-0032, QP0110-0219, and
QP0114-3140 at z ~ 1 with the aim of identifying large-scale structures- galaxy
clusters or groups- around them. This sample was observed with GMOS in Gemini
North and South telescopes in the g', r', i', and z' bands, and our photometry
is complete to a limiting magnitude of i' ~ 24 mag (corresponding to ~ M*_i' +
2 at the redshift of the pairs). Our analysis reveals that QP0110-0219 shows
very strong and QP1310+0007 and QP1355-0032 show some evidence for the presence
of rich galaxy clusters in direct vicinity of the pairs. On the other hand,
QP0114-3140 could be an isolated pair in a poor environment. This work suggest
that z ~ 1 quasar pairs are excellent tracers of high density environments and
this same technique may be useful to find clusters at higher redshifts.Comment: 29 pages, 7 figures, ApJ accepted. Added one figure and 3 references.
Some paragraphs was rewritten in sections 1, 3, 5, and 6, as suggested by
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A structure in the early Universe at z 1.3 that exceeds the homogeneity scale of the R-W concordance cosmology
A Large Quasar Group (LQG) of particularly large size and high membership has been identified in the DR7QSO catalogue of the Sloan Digital Sky Survey. It has characteristic size (volume^1/3) ~ 500 Mpc (proper size, present epoch), longest dimension ~ 1240 Mpc, membership of 73 quasars, and mean redshift = 1.27. In terms of both size and membership it is the most extreme LQG found in the DR7QSO catalogue for the redshift range 1.0 = 1.28, which is itself one of the more extreme examples. Their boundaries approach to within ~ 2 deg (~ 140 Mpc projected). This new, huge LQG appears to be the largest structure currently known in the early universe. Its size suggests incompatibility with the Yadav et al. scale of homogeneity for the concordance cosmology, and thus challenges the assumption of the cosmological principle
The properties of highly luminous IRAS galaxies
From a complete sample of 154 galaxies identified with IRAS sources in a 304 sq deg area centered on the South Galactic Pole, a subsample of 58 galaxies with L sub IR/L sub B > 3 was chosen. Low resolution spectra were obtained for 30% of the subsample and redshifts and relative emission line intensities were derived. As a class these galaxies are very luminous with = 2.9 x 10 to the 11th power L sub 0 and (L sub IR) max = 1.3 x 10 to the 12th power L sub 0. CCD images and JHK photometry were obtained for many of the subsample. The galaxies are for the most part newly identified and are optically faint, with a majority showing evidence of a recent interaction. Radio continuum observations of all galaxies of the subsample were recently obtained at 20 cm VLA with about 75% being detected in a typical integration time of about 10 minutes
Systematic review of the evidence on housing interventions for ‘housing-vulnerable’ adults and its relationship to wellbeing
Access to safe, good quality affordable housing is essential to wellbeing and housing related factors
can have an important influence on neighbourliness and sense of community belonging. A recent
scoping review on housing and wellbeing identified a lack of review-level evidence around the
impact of housing interventions on wellbeing of people who are vulnerable to discrimination or
exclusion in relation to housing (Preston et al., 2016). This systematic review was commissioned to
address that gap. We synthesise and consider the quality of evidence on how housing interventions
can contribute to improving the lives of adults who are vulnerable in relation to the security of their
housing tenure (‘housing-vulnerable’ adults)
Scaling of Horizontal and Vertical Fixational Eye Movements
Eye movements during fixation of a stationary target prevent the adaptation
of the photoreceptors to continuous illumination and inhibit fading of the
image. These random, involuntary, small, movements are restricted at long time
scales so as to keep the target at the center of the field of view. Here we use
the Detrended Fluctuation Analysis (DFA) in order to study the properties of
fixational eye movements at different time scales. Results show different
scaling behavior between horizontal and vertical movements. When the small
ballistics movements, i.e. micro-saccades, are removed, the scaling exponents
in both directions become similar. Our findings suggest that micro-saccades
enhance the persistence at short time scales mostly in the horizontal component
and much less in the vertical component. This difference may be due to the need
of continuously moving the eyes in the horizontal plane, in order to match the
stereoscopic image for different viewing distance.Comment: 5 pages, 4 figure
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