Browsing Faculty of Natural Sciences by Subject "Astronomy"
Now showing items 1-20 of 93
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The analysis of indexed astronomical time series – XI. The statistics of oversampled white noise periodograms
(Oxford University Press, 2015)The distribution of the maxima of periodograms is considered in the case where the time series is made up of regularly sampled, uncorrelated Gaussians. It is pointed out that if there is no oversampling, then for large ... -
The analysis of indexed astronomical time series – XII. The statistics of oversampled Fourier spectra of noise plus a single sinusoid
(Oxford University Press, 2015)With few exceptions, theoretical studies of periodogram properties focus on pure noise time series. This paper considers the case in which the time series consists of noise together with a single sinusoid, observed at ... -
Antenna beam characterization for the global 21-cm experiment LEDA and its impact on signal model parameter reconstruction
(Oxford University Press, 2022)Cosmic dawn, the onset of star formation in the early universe, can in principle be studied via the 21-cm transition of neutral hydrogen, for which a sky-averaged absorption signal, redshifted to MHz frequencies, is predicted ... -
An∼600 pc view of the strongly lensed, massive main-sequence galaxy j0901: A baryon-dominated, thick turbulent rotating disk with a clumpy cold gas ring at z=2.259
(American Astronomical Society, 2023)We present a high-resolution kinematic study of the massive main-sequence star-forming galaxy (SFG) SDSS J090122.37+181432.3 (J0901) at z = 2.259, using ∼0 36 Atacama Large Millimeter/submillimeter Array CO(3–2) and ∼0 ... -
Big data research infrastructure collaboration toward the SKA (BRICSKA)
(Academia Brasileira de Ciencias, 2021)Astronomy is entering an era of mega-data that will render conventional research methods as well as data and visual analytics tools ineffective. The Square Kilometre Array (SKA) drives one of the most significant big ... -
The bright extragalactic ALMA redshift survey (BEARS) – II. Millimetre photometry of gravitational lens candidates
(Oxford University Press, 2023)We present 101- and 151-GHz ALMA continuum images for 85 fields selected from Herschel observations that have 500-μm flux densities >80 mJy and 250–500-μm colours consistent with z > 2, most of which are expected to be ... -
Ceers key paper. I. An early look into the first 500myr of galaxy formation with jwst
(American Astronomical Society, 2023)We present an investigation into the first 500 Myr of galaxy evolution from the Cosmic Evolution Early Release Science (CEERS) survey. CEERS, one of 13 JWST ERS programs, targets galaxy formation from z ∼ 0.5 to >10 using ... -
Clustering of HI galaxies in the HI parkes all sky survey and arecibo legacy fast alfa survey
(Oxford University Press, 2011)We investigate the clustering of H I-selected galaxies in the Arecibo Legacy Fast ALFA Survey (ALFALFA) and compare results with those obtained for the H I Parkes All Sky Survey (HIPASS). Measurements of the angular ... -
Collective rotational bands at low excitation energy in 186Os: Vibrational and rotational degrees of freedom
(American Physical Society, 2022)Collective structures in 186Os have been investigated through the 186W(4He, 4n) 186Os reaction, at a beam energy of 48 MeV. The low-lying bands built on the excited 0+ 2 , 2+ 2 , and 4+ 3 states have been extended up ... -
A comparison of multi-phase magnetic field tracers in a high-galactic latitude region of the filamentary interstellar medium
(IOP Publishing, 2022)Understanding how the Galactic magnetic field threads the multiphase interstellar medium (ISM) remains a considerable challenge, as different magnetic field tracers probe dissimilar phases and field components. We search for ... -
Consequences of using a smooth cosmic distance in a lumpy Universe. I.
(American Physical Society, 2022)How do we appropriately fit a model based on an idealised Friedmann-Lemaˆıtre Robertson-Walker spacetime to observations made from a single location in a lumpy Universe? We address this question for surveys that measure ... -
Constraining primordial non-gaussianity by combining next-generation galaxy and 21 cm intensity mapping surveys
(SpringerOpen, 2023)Surveys of the matter distribution contain ‘fossil’ information on possible non-Gaussianity that is generated in the primordialUniverse. This primordial signal survives only on the largest scales where cosmic variance ... -
Constraining the neutrino mass using a multitracer combination of two galaxy surveys and cosmic microwave background lensing
(Oxford University Press, 2022)Measuring the total neutrino mass is one of the most exciting opportunities available with next-generation cosmological data sets. We study the possibility of detecting the total neutrino mass using large-scale clustering ... -
Continuing influence of shell effects at high-excitation energies
(Elsevier, 2019)Empirical drops in ground-state nuclear polarizabilities indicate deviations from the effect of giant dipole resonances and may reveal the presence of shell effects in semi-magic nuclei with neutron magic numbers N = 50, ... -
Cosmological constraints from the power spectrum and bispectrum of 21cm intensity maps
(IOP Publishing, 2022)The 21cm emission of neutral hydrogen is a potential probe of the matter distribution in the Universe after reionisation. Cosmological surveys of this line intensity will be conducted in the coming years by the SKAO and ... -
COSMOS2020: A panchromatic view of the universe to z ∼ 10 from two complementary catalogs
(University of the Western Cape, 2022)The Cosmic Evolution Survey (COSMOS) has become a cornerstone of extragalactic astronomy. Since the last public catalog in 2015, a wealth of new imaging and spectroscopic data have been collected in the COSMOS field. This ... -
Coulomb excitation of 102 Ru with 12 C and 16 O
(American Physical Society, 2022)The Coulomb excitation of 102Ru was performed with beams of 12C and 16O ions. The beam particles scattered at forward angles were momentum analyzed with a magnetic spectrograph. The resolution achieved enabled the ... -
Dark energy homogeneity in general relativity: Are we applying it correctly?
(Springer, 2016)Thus far, there does not appear to be an agreed (or adequate) definition of homogeneous dark energy (DE). This paper seeks to define a valid, adequate homogeneity condition for DE. Firstly, it is shown that as long as ... -
A deep radio view of the evolution of the cosmic star formation rate density from a stellar-mass-selected sample in VLA-COSMOS
(Royal Astronomical Society, 2022)We present the 1.4 GHz radio luminosity functions (RLFs) of galaxies in the Cosmic Evolution Survey (COSMOS) field, measured above and below the 5σ detection threshold, using a Bayesian model-fitting technique. The radio ... -
Designing an optimal LSST deep drilling program for cosmology with type Ia supernovae
(American Astronomical Society, 2023)The Vera C. Rubin Observatory’s Legacy Survey of Space and Time (LSST) is forecast to collect a large sample of Type Ia supernovae (SNe Ia) expected to be instrumental in unveiling the nature of dark energy. The feat, ...