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5,800 | Non-Minimal Quintessence With Nearly Flat Potential | astro-ph.CO | We consider Brans-Dicke type nonminimally coupled scalar field as a candidate
for dark energy. In the conformally transformed Einstein's frame, our model is
similar to {\it coupled quintessence} model. In such models, we consider
potentials for the scalar field which satisfy the slow-roll conditions:
$[(1/V)(dV/d\phi)]... | physics |
5,801 | Robust determination of the major merger fraction at z = 0.6 in Groth Strip | astro-ph.CO | (Abridged) We measure the fraction of galaxies undergoing disk-disk major
mergers (f_m) at intermediate redshifts (0.35 <= z < 0.85) by studying the
asymmetry index A of galaxy images. Results are provided for B- and Ks-band
absolute magnitude selected samples from the Groth strip in the GOYA
photometric survey. Three ... | physics |
5,802 | Neutrino Masses, Dark Energy and the Gravitational Lensing of Pregalactic HI | astro-ph.CO | We study the constraints which the next generation of radio telescopes could
place on the mass and number of neutrino species by studying the gravitational
lensing of high redshift 21 cm emission in combination with wide-angle surveys
of galaxy lensing. We use simple characterizations of reionization history and
of pro... | physics |
5,803 | Impact of Instrumental Systematic Contamination on the Lensing Mass Reconstruction using the CMB Polarization | astro-ph.CO | In this paper, we study the effects of instrumental systematics on the
reconstruction of the deflection angle power spectrum from weak lensing of
Cosmic Microwave Background (CMB) temperature and polarization observations. We
consider seven types of effects which are related to known instrumental
systematics: calibrati... | physics |
5,804 | Tracing the Reionization-Epoch Intergalactic Medium with Metal Absorption Lines | astro-ph.CO | IGM metal absorption lines observed in z>6 spectra offer the opportunity to
probe early feedback processes, the nature of enriching sources, and the
topology of reionization. We run high-resolution cosmological simulations
including galactic outflows to study the observability and physical properties
of 5 ions (C II, C... | physics |
5,805 | Lensing effects in inhomogeneous cosmological models | astro-ph.CO | Concepts developed in the gravitational lensing techniques such as shear,
convergence, tangential and radial arcs maybe used to see how tenable
inhomogeneous models proposed to explain the acceleration of the universe
models are. We study the widely discussed LTB cosmological models. It turns out
that for the observer ... | physics |
5,806 | Classical Cosmological Tests for Galaxies of the Hubble Ultra Deep Field | astro-ph.CO | Images of the Hubble Ultra Deep Field are analyzed to obtain a catalog of
galaxies for which the angular sizes, surface brightness, photometric
redshifts, and absolute magnitudes are found. The catalog contains a total of
about 4000 galaxies identified at a high signal-to-noise ratio, which allows
the cosmological rela... | physics |
5,807 | Gravitational waves in the Hyperspace? | astro-ph.CO | In the framework of the debate on high-frequency gravitational waves (GWs),
after a review of GWs in standard General Relativity, which is due for
completness, the possibility of merging such a traditional analysis with the
Hyperspace formalism that has been recently introduced in some papers in the
literature, with th... | physics |
5,808 | HD and H2 formation in low-metallicity dusty gas clouds at high redshift | astro-ph.CO | Context: The HD and H2 molecules play important roles in the cooling of
primordial and very metal-poor gas at high redshift. Aims: Grain surface and
gas phase formation of HD and H2 is investigated to assess the importance of
trace amounts of dust, 10^{-5}-10^{-3} Zo, in the production of HD and H2.
Methods: We conside... | physics |
5,809 | Black hole spin and radio loudness in a LCDM universe | astro-ph.CO | We use a combination of a cosmological N-body simulation of the concordance
Lambda cold dark matter (LCDM) paradigm and a semi-analytic model of galaxy
formation to investigate the spin development of central supermassive black
holes (BHs) and its relation to the BH host galaxy properties. In order to
compute BH spins,... | physics |
5,810 | The NEWFIRM Medium-Band Survey: Filter Definitions and First Results | astro-ph.CO | Deep near-infrared imaging surveys allow us to select and study distant
galaxies in the rest-frame optical, and have transformed our understanding of
the early Universe. As the vast majority of K- or IRAC-selected galaxies is too
faint for spectroscopy, the interpretation of these surveys relies almost
exclusively on p... | physics |
5,811 | ARCADE 2 Measurement of the Extra-Galactic Sky Temperature at 3-90 GHz | astro-ph.CO | The ARCADE 2 instrument has measured the absolute temperature of the sky at
frequencies 3, 8, 10, 30, and 90 GHz, using an open-aperture cryogenic
instrument observing at balloon altitudes with no emissive windows between the
beam-forming optics and the sky. An external blackbody calibrator provides an
{\it in situ} re... | physics |
5,812 | Interpretation of the Extragalactic Radio Background | astro-ph.CO | We use absolutely calibrated data between 3 and 90 GHz from the 2006 balloon
flight of the ARCADE 2 instrument, along with previous measurements at other
frequencies, to constrain models of extragalactic emission. Such emission is a
combination of the Cosmic Microwave Background (CMB) monopole, Galactic
foreground emis... | physics |
5,813 | HI and Cosmology: What We Need To Know | astro-ph.CO | There are three distinct regimes in which radio observations of the
redshifted 21 cm line of HI can contribute directly to cosmology in unique
ways. The regimes are naturally divided by redshift, from high to low, into:
inflationary physics, the Dark Ages and reionization, and galaxy evolution and
Dark Energy. Each mea... | physics |
5,814 | Early Dark Energy at High Redshifts: Status and Perspectives | astro-ph.CO | Early dark energy models, for which the contribution to the dark energy
density at high redshifts is not negligible, influence the growth of cosmic
structures and could leave observable signatures that are different from the
standard cosmological constant cold dark matter ($\Lambda$CDM) model. In this
paper, we present... | physics |
5,815 | Dark Matter | astro-ph.CO | A review of the development of the concept of dark matter is given. I begin
the review with the description of the discovery of the mass paradox in our
Galaxy and in clusters of galaxies. In mid 1970s the amount of observational
data was sufficient to suggest the presence of a massive and invisible
population around ga... | physics |
5,816 | Nonlinear Effects in the Amplitude of Cosmological Density Fluctuations | astro-ph.CO | The amplitude of cosmological density fluctuations, sigma_8, has been studied
and estimated by analysing many cosmological observations. The values of the
estimates vary considerably between the various probes. However, different
estimators probe the value of sigma_8 in different cosmological scales and do
not take int... | physics |
5,817 | The distribution of stellar mass in the low-redshift Universe | astro-ph.CO | We use a complete and uniform sample of almost half a million galaxies from
the Sloan Digital Sky Survey to characterise the distribution of stellar mass
in the low-redshift Universe. Galaxy abundances are well determined over almost
four orders of magnitude in stellar mass, and are reasonably but not perfectly
fit by ... | physics |
5,818 | Gravitational Lensing Effects on the Baryonic Acoustic Oscillation Signature in the Redshift-Space Correlation Function | astro-ph.CO | Measurements of the baryonic acoustic oscillation (BAO) peak in the
redshift-space correlation function yield the angular diameter distance D_A(z)
and the Hubble parameter H(z) as a function of redshift, constraining the
properties of dark energy and space curvature. We discuss the perturbations
introduced in the galax... | physics |
5,819 | The Formation Rates of Population III Stars and Chemical Enrichment of Halos during the Reionization Era | astro-ph.CO | [abridged] The First Stars in the Universe form out of pristine primordial
gas clouds that have been radiatively cooled to a few hundreds of degrees
Kelvin either via molecular or atomic (Lyman-Alpha) hydrogen lines. This
primordial mode of star formation is eventually quenched once radiative and/or
chemical (metal enr... | physics |
5,820 | Assumptions of the primordial spectrum and cosmological parameter estimation | astro-ph.CO | The observables of the perturbed universe, CMB anisotropy and large
structures, depend on a set of cosmological parameters, as well as, the assumed
nature of primordial perturbations. In particular, the shape of the primordial
power spectrum (PPS) is, at best, a well motivated assumption. It is known that
the assumed f... | physics |
5,821 | On the equivalence between the effective cosmology and excursion set treatments of environment | astro-ph.CO | In studies of the environmental dependence of structure formation, the large
scale environment is often thought of as providing an effective background
cosmology: e.g. the formation of structure in voids is expected to be just like
that in a less dense universe with appropriately modified Hubble and
cosmological consta... | physics |
5,822 | Cosmological Parameters from the QUaD CMB polarization experiment | astro-ph.CO | In this paper we present a parameter estimation analysis of the polarization
and temperature power spectra from the second and third season of observations
with the QUaD experiment. QUaD has for the first time detected multiple
acoustic peaks in the E-mode polarization spectrum with high significance.
Although QUaD-onl... | physics |
5,823 | CMB Lensing Constraints on Neutrinos and Dark Energy | astro-ph.CO | Signatures of lensing of the cosmic microwave background radiation by
gravitational potentials along the line of sight carry with them information on
the matter distribution, neutrino masses, and dark energy properties. We
examine the constraints that Planck, PolarBear, and CMBpol future data,
including from the B-mode... | physics |
5,824 | Lensed Cosmic Microwave Background Constraints on Post-General Relativity Parameters | astro-ph.CO | The constraints on departures from general relativity (GR) at cosmological
length scales due to cosmic microwave background (CMB) data are discussed. The
departure from GR is measured by the ratio, parameterized as $1 +\varpi_0 (1 +
z)^{-S}$, between the gravitational potentials conventionally appearing in the
geodesic... | physics |
5,825 | A Multi-Parameter Investigation of Gravitational Slip | astro-ph.CO | A detailed analysis of gravitational slip, a new post-general relativity
cosmological parameter characterizing the degree of departure of the laws of
gravitation from general relativity on cosmological scales, is presented. This
phenomenological approach assumes that cosmic acceleration is due to new
gravitational effe... | physics |
5,826 | Dark Matter Angular Momentum Profile from the Jeans Equation | astro-ph.CO | Cosmological simulations of dark matter structures have shown that the
equilibrated dark matter structures have a fairly small angular momentum. It
appears from these N-body simulations that the radial profile of the angular
momentum has an almost universal behavior, even if the different dark matter
structures have ex... | physics |
5,827 | Measuring the tensor to scalar ratio from CMB B-modes in presence of foregrounds | astro-ph.CO | Abreg: We investigate the impact of polarized foreground emission on the
performances of future CMB experiments in measuring the tensor-to-scalar ratio
r. We design a component separation pipeline, based on the Smica method, aimed
at estimating r and the foreground contamination from the data with no prior
assumption o... | physics |
5,828 | Primordial black holes are again on the limelight | astro-ph.CO | We derive a strong upper bound on the amount of Primordial Black Holes (PBHs)
that can still be present in the Universe. Gravitational capture of PBHs by the
Milky Way stars during their formation and subsequent accretion would produce a
dramatic depletion of disk stars and especially of white dwarfs, unless the
averag... | physics |
5,829 | Self-Consistent Solution of Cosmological Radiation-Hydrodynamics and Chemical Ionization | astro-ph.CO | We consider a PDE system comprising compressible hydrodynamics, flux-limited
diffusion radiation transport and chemical ionization kinetics in a
cosmologically-expanding universe. Under an operator-split framework, the
cosmological hydrodynamics equations are solved through the Piecewise Parabolic
Method, as implemente... | physics |
5,830 | The Many Manifestations of Downsizing: Hierarchical Galaxy Formation Models confront Observations | astro-ph.CO | [abridged] It has been widely claimed that several lines of observational
evidence point towards a "downsizing" (DS) of the process of galaxy formation
over cosmic time. This behavior is sometimes termed "anti-hierarchical", and
contrasted with the "bottom-up" assembly of the dark matter structures in Cold
Dark Matter ... | physics |
5,831 | A gravitationally lensed water maser in the early Universe | astro-ph.CO | Water masers are found in dense molecular clouds closely associated with
supermassive black holes in the centres of active galaxies. Based upon the
understanding of the local water maser luminosity function, it was expected
that masers at intermediate and high redshifts would be extremely rare, but
galaxies at redshift... | physics |
5,832 | The ACS Fornax Cluster Survey. V. Measurement and Recalibration of Surface Brightness Fluctuations and a Precise Value of the Fornax--Virgo Relative Distance | astro-ph.CO | We present g-z color and z-band surface brightness fluctuations (SBF)
measurements for 43 early-type galaxies in the Fornax cluster imaged with
HST/ACS. These are combined with measurements for Virgo cluster galaxies to
derive a revised, nonlinear calibration of the z-band SBF absolute magnitude as
a function of g-z. I... | physics |
5,833 | Structural Properties of Central Galaxies in Groups and Clusters | astro-ph.CO | Using a representative sample of 911 central galaxies (CENs) from the SDSS
DR4 group catalogue, we study how the structure of the most massive members in
groups and clusters depend on (1) galaxy stellar mass (Mstar), (2) dark matter
halo mass of the host group (Mhalo), and (3) their halo-centric position. We
establish ... | physics |
5,834 | A review of the stochastic background of gravitational waves in f(R) gravity with WMAP constrains | astro-ph.CO | This paper is a review of previous works on the stochastic background of
gravitational waves (SBGWs) which has been discussed in various peer-reviewed
journals and international conferences. The SBGWs is analyzed with the aid of
the Wilkinson Microwave Anisotropy Probe (WMAP) data. We emphasize that, in
general, in pre... | physics |
5,835 | Comment on the claimed radial BAO detection by Gaztanaga et al | astro-ph.CO | Gaztanaga et al. have recently claimed to measure the Baryon Acoustic
Oscillation (BAO) scale in the radial direction from the publicly available
SDSS DR6 data. They focus on the correlation function of Luminous Red Galaxies
(LRG) close to the line-of-sight direction to find a feature that they identify
as the BAO peak... | physics |
5,836 | The evolution of the red sequence slope in massive galaxy clusters | astro-ph.CO | We investigate the evolution of the optical and near-infrared
colour-magnitude relation in an homogeneous sample of massive clusters from z =
1 to the present epoch. By comparing deep Hubble Space Telescope ACS imaging of
X-ray selected MACS survey clusters at z = 0.5 to the similarly selected LARCS
sample at z = 0.1 w... | physics |
5,837 | Clustering in growing neutrino cosmologies | astro-ph.CO | We show that growing neutrino models, in which the growing neutrino mass
stops the dynamical evolution of a dark energy scalar field, lead to a
substantial neutrino clustering on the scales of superclusters. Nonlinear
neutrino lumps form at redshift z ~ 1 and could partially drag the clustering
of dark matter. If obser... | physics |
5,838 | Dissecting Galaxy Formation: I. Comparison Between Pure Dark Matter and Baryonic Models | astro-ph.CO | We compare assembly of DM halos with and without baryons, within the context
of cosmological evolution in the LCDM WMAP3 Universe (baryons+DM, BDM model,
and pure DM, PDM model). In representative PDM and BDM models we find that
baryons contribute decisively to the evolution of the central region, leading
to an isother... | physics |
5,839 | Evolution in the structural properties of early-type Brightest Cluster Galaxies at small lookback time and dependence on the environment | astro-ph.CO | At the present time, SDSS early-type BCGs have larger Re than early-type
galaxies of similar L, whether these other objects are in the field, or are
satellites in clusters (Re ~ L for BCGs). At fixed M* and formation time, BCGs
at lower z are larger and have smaller velocity dispersions, i.e. Re increases
and sigma dec... | physics |
5,840 | The formation and evolution of early-type galaxies : solid results and open questions | astro-ph.CO | The most recent results and some of the open key questions on the evolution
of early-type galaxies are reviewed in the general cosmological context of
massive galaxy formation. | physics |
5,841 | Relativistic MOND as an alternative to the dark matter paradigm | astro-ph.CO | Milgrom's Modified Newtonian dynamics (MOND) provides an efficient way to
summarize phenomenology of galaxies which does not lean on the notion of dark
matter; it has great predictive power. Here I briefly review MOND as well as
its implementation as a nonrelativistic modified gravity theory, AQUAL.
Gravitational lensi... | physics |
5,842 | Prospects for the direct detection of the cosmic neutrino background | astro-ph.CO | The existence of a cosmic neutrino background -- the analogue of the cosmic
microwave background -- is a fundamental prediction of standard big bang
cosmology. Up to now, the observational evidence for its existence is rather
indirect and rests entirely on cosmological observations of, e.g., the light
elemental abundan... | physics |
5,843 | The 0.4 < z < 1.3 star formation history of the Universe as viewed in the far-infrared | astro-ph.CO | [Abridged] We use the deepest existing mid- and far-infrared observations
(reaching ~3 mJy at 70 um) obtained with Spitzer in the GOODS and FIDEL fields
to derive the evolution of the rest-frame 15 um, 35 um, and total infrared
luminosity functions of galaxies spanning z < 1.3. In comparison with previous
studies, the ... | physics |
5,844 | The statistics of voids as a tool to constrain cosmological parameters: sigma_8 and Omega_m h | astro-ph.CO | We present a general analytical formalism to calculate accurately several
statistics related to underdense regions in the Universe. The statistics are
computed for dark matter halo and galaxy distributions both in real space and
redshift space at any redshift. Using this formalism, we found that void
statistics for gal... | physics |
5,845 | Model Independent Foreground Power Spectrum Estimation using WMAP 5-year Data | astro-ph.CO | In this paper, we propose & implement on WMAP 5-year data, a model
independent approach of foreground power spectrum estimation for multifrequency
observations of CMB experiments. Recently a model independent approach of CMB
power spectrum estimation was proposed by Saha et al. 2006. This methodology
demonstrates that ... | physics |
5,846 | Three-dimensional Magnetohydrodynamic Simulations of Buoyant Bubbles in Galaxy Clusters | astro-ph.CO | We report results of 3D MHD simulations of the dynamics of buoyant bubbles in
magnetized galaxy cluster media. The simulations are three dimensional
extensions of two dimensional calculations reported by Jones & De Young (2005).
Initially spherical bubbles and briefly inflated spherical bubbles all with
radii a few tim... | physics |
5,847 | Slow dynamos and decay of monopole magnetic fields in the early Universe | astro-ph.CO | Previously Liao and Shuryak [\textbf{Phys. Rev C (2008)}] have investigated
electrical flux tubes in monopole plasmas, where magnetic fields are
non-solenoidal in quark-QCD plasmas. In this paper slow dynamos in diffusive
plasma [{\textbf{Phys. Plasmas \textbf{15} (2008)}}] filaments (thin tubes) are
obtained in the ca... | physics |
5,848 | Dark energy and the Rutherford-Soddy radiative decay law | astro-ph.CO | It is shown that a putative evolution of the fundamental couplings of strong
and weak interactions via coupling to dark energy through a generalized
Bekenstein-type model may, for a linear model of variation, cause deviations on
the statistical nuclear decay Rutherford-Soddy law unless bounds are imposed on
the paramet... | physics |
5,849 | CMB anisotropies from acausal scaling seeds | astro-ph.CO | We investigate models where structure formation is initiated by scaling
seeds: We consider rapidly expanding relativistic shells of energy and show
that they can fit current CMB and large scale structure data if they expand
with super-luminal velocities. These acausally expanding shells provide a
viable alternative to ... | physics |
5,850 | Cosmic queuing: galaxy satellites, building blocks and the hierarchical clustering paradigm | astro-ph.CO | We study the properties of building blocks (BBs, i.e. accreted satellites)
and surviving satellites of present-day galaxies using the SAG semi-analytic
model of galaxy formation in the context of a concordance Lambda Cold Dark
Matter (LCDM) cosmology. We consider large numbers of DM halo merger trees
spanning a wide ra... | physics |
5,851 | The Equation of State of the Intergalactic Medium After Hydrogen Reionization | astro-ph.CO | We use an analytic model to study how inhomogeneous hydrogen reionization
affects the temperature distribution of the intergalactic medium (IGM). During
this process, the residual energy of each ionizing photon is deposited in the
IGM as heat, increasing its temperature to 20,000-30,000 K; subsequent
expansion of the U... | physics |
5,852 | Satellite galaxy velocity dispersions in the SDSS and modified gravity models | astro-ph.CO | The Sloan Digital Sky Survey (SDSS) provides data on several hundred thousand
galaxies. Precise location of these galaxies in the sky, along with information
about their luminosities and line-of-sight (Doppler) velocities allows one to
construct a three-dimensional map of their location and estimate their
line-of-sight... | physics |
5,853 | A search for diffuse radio emission in the relaxed, cool-core galaxy clusters A1068, A1413, A1650, A1835, A2029, and Ophiuchus | astro-ph.CO | We analyze sensitive, high-dynamic-range, observations to search for
extended, diffuse, radio emission in relaxed and cool-core galaxy clusters. We
performed deep 1.4 GHz Very Large Array observations, of A1068, A1413, A1650,
A1835, A2029, and complemented our dataset with archival observations of
Ophiuchus. We find th... | physics |
5,854 | Comparative analysis of the diffuse radio emission in the galaxy clusters A1835, A2029, and Ophiuchus | astro-ph.CO | We recently performed a study of a sample of relaxed, cooling core galaxy
clusters with deep Very Large Array observations at 1.4 GHz. We find that in
the central regions of A1835, A2029, and Ophiuchus the dominant radio galaxy is
surrounded by a diffuse low-brightness radio emission that takes the form of a
mini-halo.... | physics |
5,855 | The search for DM in nearby dSph galaxies with MAGIC: candidates, results and prospects | astro-ph.CO | At present, dwarf spheroidal galaxies satellites of the Milky Way may
represent the best astrophysical objects for dark matter (DM) searches with
gamma-ray telescopes. They present the highest mass-to-light ratios known in
the Universe. Furthermore, many of them are near enough from the Earth to be
able to yield high p... | physics |
5,856 | The WMAP cold spot | astro-ph.CO | The WMAP cold spot was found by applying spherical wavelets to the first year
WMAP data. An excess of kurtosis of the wavelet coefficient was observed at
angular scales of around 5 degrees. This excess was shown to be inconsistent
with Gaussian simulations with a p-value of around 1%. A cold spot centered at
(b = -57, ... | physics |
5,857 | ASKI: full-sky lensing map making algorithms | astro-ph.CO | Within the context of upcoming full-sky lensing surveys, the edge-preserving
non- linear algorithm Aski is presented. Using the framework of Maximum A
Posteriori inversion, it aims at recovering the full-sky convergence map from
surveys with masks. It proceeds in two steps: CCD images of crowded galactic
fields are deb... | physics |
5,858 | Testing Oscillating Primordial Spectrum and Oscillating Dark Energy with Astronomical Observations | astro-ph.CO | In this paper we revisit the issue of determining the oscillating primordial
scalar power spectrum and oscillating equation of state of dark energy from the
astronomical observations. By performing a global analysis with the Markov
Chain Monte Carlo method, we find that the current observations from five-year
WMAP and ... | physics |
5,859 | Gravitational Lensing Effect on the Two-Point Correlation Function of Hot Spots in 21 cm fluctuations | astro-ph.CO | We investigate the weak gravitational lensing effect on the two-point
correlation function of local maxima (hot spots) in the cosmic 21 cm
fluctuation map. The intrinsic two-point function has a pronounced depression
feature around the angular scale of $\theta \sim 40$ arcmin, which depends on
the observed frequency an... | physics |
5,860 | Analysis of the RC catalog sample in the region overlapping with the regions of the FIRST and SDSS surveys: I. Identification of sources with the VLSS, TXS, NVSS, FIRST, and GB6 catalogs | astro-ph.CO | Radio sources of the RC catalog produced in 1980--1985 at RATAN-600 radio
telescope based on a deep survey of a sky strip centered on the declination of
the SS 433 source are optically identified in the region overlapping with FIRST
and SDSS surveys (about 132 square degrees). The NVSS catalog was used as the
reference... | physics |
5,861 | Current lookback time-redshift bounds on dark energy | astro-ph.CO | We investigate observational constraints on dark energy models from lookback
time (LT) estimates of 32 old passive galaxies distributed over the redshift
interval $0.11 \leq z \leq 1.84$. To build up our LT sample we combine the age
measurements for these 32 objects with estimates of the total age of the
Universe, as o... | physics |
5,862 | Decaying dark matter in Draco | astro-ph.CO | Context. The sterile neutrino is an excellent dark matter candidate, which
can be searched for in a wide range of astrophysical sites. It has previously
been shown that the optimal search strategy is to consider dwarf galaxies
belonging to the Milky Way. Aims. We search for line emission from decaying
dark matter. Meth... | physics |
5,863 | Optimal limits on f_{NL}^{local} from WMAP 5-year data | astro-ph.CO | We have applied the optimal estimator for f_{NL}^{local} to the 5 year WMAP
data. Marginalizing over the amplitude of foreground templates we get -4 <
f_{NL}^{local} < 80 at 95% CL. Error bars of previous (sub-optimal) analyses
are roughly 40% larger than these. The probability that a Gaussian simulation,
analyzed usin... | physics |
5,864 | Spatial Correlations in the Helium-Ionizing Background | astro-ph.CO | After quasars ionize intergalactic HeII at z~3, a large radiation field
builds up above the HeII ionization edge. Unlike the background responsible for
HI ionizations, this field should be highly variable, thanks to the scarcity of
bright quasars and the relatively short attenuation lengths (~50 Mpc) of these
high-ener... | physics |
5,865 | The WiggleZ Dark Energy Survey: small-scale clustering of Lyman Break Galaxies at z < 1 | astro-ph.CO | The WiggleZ Dark Energy Survey is a large-scale structure survey of
intermediate-redshift UV-selected emission-line galaxies scheduled to cover
1000 sq deg, spanning a broad redshift range 0.2 < z < 1.0. The main scientific
goal of the survey is the measurement of baryon acoustic oscillations (BAO) in
the galaxy cluste... | physics |
5,866 | Compatibility of DAMA/LIBRA dark matter detection with other searches in light of new Galactic rotation velocity measurements | astro-ph.CO | The DAMA/NaI and DAMA/LIBRA annual modulation data, which may be interpreted
as a signal for the existence of weakly interacting dark matter (WIMPs) in our
galactic halo, are re-examined in light of new measurements of the local
velocity relative to the galactic halo. In the vicinity of the Sun, the
velocity of the Gal... | physics |
5,867 | A Decade of Dark Energy: 1998 - 2008 | astro-ph.CO | The years 1998 to 2008 were very exciting years for cosmology. It was a
pleasure to accept this invitation to describe my contributions to the
development of our knowledge and understanding of the universe over the course
of the past decade. Here, I begin by describing some of my work on radio
galaxies as a modified st... | physics |
5,868 | Anisotropy probe of galactic and extra-galactic Dark Matter annihilations | astro-ph.CO | We study the flux and the angular power spectrum of gamma-rays produced by
Dark Matter (DM) annihilations in the Milky Way (MW) and in extra-galactic
halos. The annihilation signal receives contributions from: a) the smooth MW
halo, b) resolved and unresolved substructures in the MW, c) external DM halos
at all redshif... | physics |
5,869 | Transverse motions in CSOs? | astro-ph.CO | The measurement of proper motions in CSOs is a powerful tool to determine the
dynamical evolution of the newly born extragalactic radio sources. We observed
3 CSOs with the VLBA in 2004 and in 2006 to monitor changes in their structure
and measure the separation velocity of the hot spots. It is important to
increase th... | physics |
5,870 | High Frequency Peakers: The Faint Sample | astro-ph.CO | We present a sample of sources with convex radio spectra peaking at
frequencies above a few GHz, known as "High Frequency Peakers" (HFPs). A
"bright" sample with a flux density limit of 300 mJy at 5 GHz has been
presented by Dallacasa et al. (2000). Here we present the "faint" sample with
flux density between 50 and 30... | physics |
5,871 | Internal resonance in non-linear disk oscillations and the amplitude evolution of neutron star kilohertz QPOs | astro-ph.CO | We explore some properties of twin kilohertz quasiperiodic oscillations
(QPOs) in a simple toy-model consisting of two oscillation modes coupled by a
general nonlinear force. We examine resonant effects by slowly varying the
values of the tunable, and nearly commensurable, eigenfrequencies. The behavior
of the actual o... | physics |
5,872 | Locating the Baryon Acoustic Peak | astro-ph.CO | Forthcoming photometric redshift surveys should provide an accurate probe of
the acoustic peak in the two-point galaxy correlation function, in the form of
angular clustering of galaxies within a given shell in redshift space. We
investigate the form of the anticipated signal, quantifying the distortions
that arise due... | physics |
5,873 | Distance to NGC 0247 | astro-ph.CO | We report VRI CCD observations of nine Cepheids in the South Polar (Sculptor)
Group spiral galaxy NGC 0247. Periods of these Cepheids range from 20 to 70
days. Over the past 20 years the very brightest Cepheid in our sample, NGC
0247:[MF09] C1, has decreased its period by 6%, faded by 0.8 mag in the V band,
and become ... | physics |
5,874 | The Evolution of Field Early-Type Galaxies in the FDF and WHDF | astro-ph.CO | We explore the properties of 24 field early-type galaxies at 0.20<z<0.75 down
to M_B<=-19.30 in a sample extracted from the FORS Deep Field and the William
Herschel Deep Field. High S/N intermediate-resolution VLT spectroscopy was
complemented by deep high-resolution HST/ACS imaging and additional
ground-based multi-ba... | physics |
5,875 | An Estimate of the Primordial Non-Gaussianity Parameter f_NL Using the Needlet Bispectrum from WMAP | astro-ph.CO | We use the full bispectrum of spherical needlets applied to the WMAP data of
the cosmic microwave background as an estimator for the primordial
non-Gaussianity parameter f_NL. We use needlet scales up to l_max=1000 and the
KQ75 galactic cut and find f_NL=84 +/- 40 corrected for point source bias. We
also introduce a se... | physics |
5,876 | An updated Gamma Ray Bursts Hubble diagram | astro-ph.CO | Gamma ray bursts (GRBs) have recently attracted much attention as a possible
way to extend the Hubble diagram to very high redshift. To this aim, the
luminosity (or isotropic emitted energy) of a GRB at redshift z must be
evaluated from a correlation with a distance independent quantity so that one
can then solve for t... | physics |
5,877 | The non-Gaussianity of the cosmic shear likelihood - or: How odd is the Chandra Deep Field South? | astro-ph.CO | (abridged) We study the validity of the approximation of a Gaussian cosmic
shear likelihood. We estimate the true likelihood for a fiducial cosmological
model from a large set of ray-tracing simulations and investigate the impact of
non-Gaussianity on cosmological parameter estimation. We investigate how odd
the recent... | physics |
5,878 | On the large-scale instability in interacting dark energy and dark matter fluids | astro-ph.CO | Recently, Valiviita et al. (2008) have reported a large-scale early-time
instability in coupled dark energy and dark matter models. We take the same
form of energy-momentum exchange and specialise to the case when the
interaction rate is proportional to Hubble's parameter and the dark energy
density only. Provided the ... | physics |
5,879 | Searching for massive galaxies at z>=3.5 in GOODS-North | astro-ph.CO | We constrain the space density and properties of massive galaxy candidates at
redshifts of z>=3.5 in the GOODS-N field. By selecting sources in the
Spitzer+IRAC bands, a highly stellar mass-complete sample is
assembled,including massive galaxies which are very faint in the
optical/near-IR bands that would be missed by ... | physics |
5,880 | The growth and assembly of a massive galaxy at z ~ 2 | astro-ph.CO | We study the stellar mass assembly of the Spiderweb Galaxy (MRC 1138-262), a
massive z = 2.2 radio galaxy in a protocluster and the probable progenitor of a
brightest cluster galaxy. Nearby protocluster galaxies are identified and their
properties are determined by fitting stellar population models to their
rest-frame ... | physics |
5,881 | How flat can you get? A model comparison perspective on the curvature of the Universe | astro-ph.CO | The question of determining the spatial geometry of the Universe is of
greater relevance than ever, as precision cosmology promises to verify
inflationary predictions about the curvature of the Universe. We revisit the
question of what can be learnt about the spatial geometry of the Universe from
the perspective of a t... | physics |
5,882 | Black Hole Masses of Intermediate-Redshift Quasars: Near Infrared Spectroscopy | astro-ph.CO | We present near-infrared spectra of ten luminous, intermediate redshift
quasars observed with SofI at the NTT of ESO/La Silla. With these rest-frame
optical spectra we probe the Hb -[OIII] emission line region. Using the
standard scaling relation involving the width of the Hb line and the continuum
luminosity, we measu... | physics |
5,883 | A Search for Molecular Gas toward a BzK-selected Star-forming Galaxy at z = 2.044 | astro-ph.CO | We present a search for CO(3-2) emission in SDF-26821, a BzK-selected
star-forming galaxy (sBzK) at z = 2.044, using the 45-m telescope of the
Nobeyama Radio Observatory and the Nobeyama Millimeter Array. We do not detect
significant emission and derive 2 \sigma limits: the CO luminosity of L'CO <
3.1 x 10^10 K km s^{-... | physics |
5,884 | Internal dynamics of the galaxy cluster Abell 959 | astro-ph.CO | The connection of cluster mergers with the presence of extended, diffuse
radio sources in galaxy clusters is still being debated. In this paper we aim
to obtain new insights into the internal dynamics of Abell 959, showing
evidence of a diffuse radio source, analyzing velocities and positions of
member galaxies. Our an... | physics |
5,885 | Cosmology with the cluster mass function: mass estimators and shape systematics in large weak lensing surveys | astro-ph.CO | Accurate measurement of the cluster mass function is a crucial element in
efforts to constrain structure formation models, the normalisation of the
matter power spectrum and the cosmological matter density, and the nature and
evolution of dark energy. Large weak lensing surveys of ~20,000 galaxy clusters
and groups wil... | physics |
5,886 | OTELO Survey: Deep BVRI broadband photometry of the Groth strip. II Properties of X-ray Emitters | astro-ph.CO | The Groth field is one of the sky regions that will be targeted by the OTELO
(OSIRIS Tunable Filter Emission Line Object) survey in the optical 820 nm and
920 nm atmospheric windows. This field has been observed by AEGIS
(All-wavelength Extended Groth strip International Survey) covering the full
spectral range, from X... | physics |
5,887 | The Near-IR Luminosity Function and Bimodal Surface Brightness Distribution of Virgo Cluster Galaxies | astro-ph.CO | We have acquired deep, H-band, imaging for a sample of 286 Virgo cluster
galaxies with B <= 16 mag and extracted surface photometry from optical g,r,i,z
Sloan Digital Sky Survey images of 742 Virgo Cluster Catalog galaxies,
including those with H-band images. We confirm the detection of a dip in the
luminosity function... | physics |
5,888 | The Strongest 100 Point Radio Sources in the LMC at 1.4 GHz | astro-ph.CO | We present the 100 strongest 1.4 GHz point sources from a new mosaic image in
the direction of the Large Magellanic Cloud (LMC). The observations making up
the mosaic were made over a ten year period and were combined with Parkes
single dish data at 1.4 GHz to complete the image for short spacing. An initial
list of co... | physics |
5,889 | Modelling non-Gaussianity from foreground contaminants | astro-ph.CO | We introduce a general class of models for charaterizing the non-Gaussian
properties of foreground contaminants in the cosmic microwave background with
view towards the removal of the non-primordial non-Gaussian signal from the
primordial one. This is important not only for treating temperature maps but
also for charac... | physics |
5,890 | Gravitational Wave Detection Using Redshifted 21-cm Observations | astro-ph.CO | A gravitational wave traversing the line of sight to a distant source
produces a frequency shift which contributes to redshift space distortion. As a
consequence, gravitational waves are imprinted as density fluctuations in
redshift space. The gravitational wave contribution to the redshift space power
spectrum. has a ... | physics |
5,891 | Evolution of the optical Tully-Fisher relation up to z=1.3 | astro-ph.CO | The study of the evolution of the Tully-Fisher relation has been
controversial in the past years. The main difficulty is in determining the
required parameters for intermediate and high redshift galaxies.
This work aims to identify the main problems of the study of the Tully-Fisher
relation at high redshift using opt... | physics |
5,892 | Giant Radio Galaxies - old long-living quasars? | astro-ph.CO | Based on the miscellaneous published radio and optical data, SDSS and APM
catalogue we consider the various properties of the giant radio sources (gRS)
with the aim of refining the conditions leading to the formation of these
objects. We compare gRSs with the regular-sized radio sources in radio and
optical bands, yiel... | physics |
5,893 | Central mass-to-light ratios and dark matter fractions in early-type galaxies | astro-ph.CO | Dynamical studies of local ETGs and the Fundamental Plane point to a strong
dependence of M/L ratio on luminosity (and stellar mass) with a relation of the
form $M/L \propto L^{\gamma}$. The "tilt" $\gamma$ may be caused by various
factors, including stellar population properties, IMF, rotational support,
luminosity pr... | physics |
5,894 | Multi-scale cluster lens mass mapping I. Strong Lensing modelling | astro-ph.CO | We propose a novel technique to refine the modelling of galaxy clusters mass
distribution using gravitational lensing. The idea is to combine the strengths
of both "parametric" and "non-parametric" methods to improve the quality of the
fit. We develop a multi-scale model that allows sharper contrast in regions of
highe... | physics |
5,895 | X-Ray Absorption By WHIM in the Sculptor Wall | astro-ph.CO | We present XMM RGS and Chandra LETG observations of the blazar, H 2356-309,
located behind the Sculptor Wall, a large-scale galaxy structure expected to
harbor high-density Warm-Hot Intergalactic Medium (WHIM). Our simultaneous
analysis of the RGS and LETG spectra yields a 3-sigma detection of the crucial
redshifted O ... | physics |
5,896 | The Building the Bridge survey for z=3 Ly-alpha emitting galaxies II: Completion of the survey | astro-ph.CO | (Abridged). We aim at bridging the gap between absorption selected and
emission selected galaxies at z~3 by probing the faint end of the luminosity
function of star-forming galaxies at z~3. We have performed narrow-band imaging
in three fields with intervening QSO absorbers (a damped Ly$\alpha$ absorber
and two Lyman-l... | physics |
5,897 | Neutrinos of non-zero rest mass and the equivalence principle | astro-ph.CO | Assuming that neutrinos of non-zero rest mass dominate the mass density in
the universe, and also the mass density on the scale of clusters of galaxies,
one obtains the upper limit m < 20 eV/c^2 on their mass, independent of the
values of H_0 and q_0, and the lower limit m > 5 eV/c^2 independent of q_0 and
almost indep... | physics |
5,898 | The evolution of the Lyman-alpha forest effective optical depth following HeII reionisation | astro-ph.CO | Three independent observational studies have now detected a narrow (\Delta z
~ 0.5) dip centred at z=3.2 in the otherwise smooth redshift evolution of the
Lya forest effective optical depth. This feature has previously been
interpreted as an indirect signature of rapid photo-heating in the IGM during
the epoch of HeII ... | physics |
5,899 | The optical afterglows and host galaxies of three short/hard gamma-ray bursts | astro-ph.CO | Short GRBs are commonly thought to originate from the merging of double
compact object binaries but direct evidence for this scenario is still missing.
Optical observations of short GRBs allow us to measure redshifts, firmly
identify host galaxies, characterize their properties, and accurately localize
GRBs within them... | physics |
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