Browsing Research Articles (Physics) by Title
Now showing items 219-238 of 510
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The host haloes of O I absorbers in the reionization epoch
(Oxford University Press, 2013)We use a radiation hydrodynamic simulation of the hydrogen reionization epoch to study OI absorbers at z ∼ 6. The intergalactic medium (IGM) is reionized before it is enriched; hence, OI absorption originates within dark ... -
Hot subdwarf stars in close-up view IV. Helium abundances and the 3He isotopic anomaly of subdwarf B stars
(EDP Sciences, 2013)Atmospheric parameters and helium abundances of 44 bright subdwarf B stars have been determined. More than half of our sample consists of newly discovered stars from the Edinburgh Cape survey. We showed that effective ... -
Hot white dwarfs and pre-white dwarfs discovered with SALT
(Oxford University Press, 2023)The Southern African Large Telescope survey of helium-rich hot subdwarfs aims to explore evolutionary pathways among groups of highly evolved stars. The selection criteria mean that several hot white dwarfs and related ... -
How open data and interdisciplinary collaboration improve our understanding of space weather: A risk and resiliency perspective
(Frontiers Media, 2022)Space weather refers to conditions around a star, like our Sun, and its interplanetary space that may affect space- and ground-based assets as well as human life. Space weather can manifest as many different phenomena, often ... -
How well can we measure the stellar mass of a galaxy: The impact of the assumed star formation history model in SED fitting
(IOP Publishing, 2020)The primary method for inferring the stellar mass (M∗) of a galaxy is through spectral energy distribution (SED) modeling. However, the technique rests on assumptions such as the galaxy star formation history and dust ... -
The Hubble constant tension with next-generation galaxy surveys
(IOP Publishing Ltd, 2020)The rate at which the universe is expanding today is a fundamental parameter in cosmology which governs our understanding of structure formation and dark energy. However, current measurements of the Hubble constant, H0, ... -
Hunting down horizon-scale effects with multi-wavelength surveys
(American Astronomical Society, 2015)Next-generation cosmological surveys will probe ever larger volumes of the universe, including the largest scales, near and beyond the horizon. On these scales, the galaxy power spectrum carries signatures of local primordial ... -
Hybrid P` (k): General, unified, non-linear matter power spectrum in redshift space
(IOP Publishing Ltd, 2020)Constraints on gravity and cosmology will greatly benefit from performing joint clustering and weak lensing analyses on large-scale structure data sets. Utilising non-linear information coming from small physical scales ... -
Hydra I: An extensible multi-source-finder comparison and cataloguing tool
(Cambridge University Press, 2023)The latest generation of radio surveys are now producing sky survey images containing many millions of radio sources. In this context it is highly desirable to understand the performance of radio image source finder (SF) ... -
Hydra ii: Characterisation of Aegean, Caesar, profound, pybdsf, and selavy source finders
(Cambridge University Press, 2023)We present a comparison between the performance of a selection of source finders using a new software tool called Hydra. The companion paper, Paper I, introduced the Hydra tool and demonstrated its performance using ... -
Identification of single spectral lines in large spectroscopic surveys using UMLAUT: an Unsupervised Machine Learning Algorithm based on Unbiased Topology
(The Astrophysical Journal Supplement Series, 2021)The identification of an emission line is unambiguous when multiple spectral features are clearly visible in the same spectrum.However, in many cases, only one line is detected, making it difficult to correctly determine ... -
Identifying multiple periodicities in sparse photon event time series
(Oxford University Press, 2016)The data considered are event times (e.g. photon arrival times, or the occurrence of sharp pulses). The source is multiperiodic, or the data could be multiperiodic because several unresolved sources contribute to the time ... -
The Impact of Observing Strategy on Cosmological Constraints with LSST
(2022)The generation-defining Vera C. Rubin Observatory will make state-of-the-art measurements of both the static and transient universe through its Legacy Survey for Space and Time (LSST). With such capabilities, it is immensely ... -
The impact of quenching on galaxy profiles in the SIMBA simulation
(Oxford University Press, 2020)We study specific star formation rate (sSFR) and gas profiles of star-forming (SF) and green valley (GV) galaxies in the SIMBA cosmological hydrodynamic simulation. SF galaxy half-light radii (Rhalf) at z = 0 and their ... -
Impact of Rubin observatory cadence choices on supernovae photometric classification
(American Astronomical Society, 2023)The Vera C. Rubin Observatory’s Legacy Survey of Space and Time (LSST) will discover an unprecedented number of supernovae (SNe), making spectroscopic classification for all the events infeasible. LSST will thus rely on ... -
Impact of Rubin Observatory Cadence Choices on Supernovae Photometric Classification
(The Astrophysical Journal Supplement Series, 2023)The Vera C. Rubin Observatory’s Legacy Survey of Space and Time (LSST) will discover an unprecedented number of supernovae (SNe), making spectroscopic classification for all the events infeasible. LSST will thus rely on ... -
The impact of solar wind variability on pulsar timing
(EDP Sciences, 2021)Context. High-precision pulsar timing requires accurate corrections for dispersive delays of radio waves, parametrized by the dispersion measure (DM), particularly if these delays are variable in time. In a previous paper, ... -
The impact of the connectivity of the cosmic web on the physical properties of galaxies at its nodes
(Oxford University Press, 2019)We investigate the impact of the number of filaments connected to the nodes of the cosmic web on the physical properties of their galaxies using the Sloan Digital Sky Survey. We compare these measurements to the cosmological ... -
The impact of wind scalings on stellar growth and the baryon cycle in cosmological simulations
(Oxford University Press, 2020)Many phenomenologically successful cosmological simulations employ kinetic winds to model galactic outflows. Yet systematic studies of how variations in kinetic wind scalings might alter observable galaxy properties are ... -
Imprints of temperature fluctuations on the z ∼ 5 Lyman-α forest: a view from radiation-hydrodynamic simulations of reionization
(Oxford academic, 2019)Reionization leads to large spatial fluctuations in the intergalactic temperature that can persist well after its completion. We study the imprints of such fluctuations on the z ∼ 5 Ly α forest flux power spectrum using ...