2,989 research outputs found
Euclid preparation. The Cosmic Dawn Survey (DAWN) of the Euclid Deep and Auxiliary Fields
No full textEuclid will provide deep NIR imaging to 26.5 AB magnitude over 59
deg in its deep and auxiliary fields. The Cosmic DAWN survey complements
the deep Euclid data with matched depth multiwavelength imaging and
spectroscopy in the UV--IR to provide consistently processed Euclid selected
photometric catalogs, accurate photometric redshifts, and measurements of
galaxy properties to a redshift of . In this paper, we present an
overview of the survey, including the footprints of the survey fields, the
existing and planned observations, and the primary science goals for the
combined data set.Comment: 16 pages, 10 figures, submitted to A&A; Updated references; Updated
author lis
Galaxy clustering at cosmic dawn from JWST/NIRCam observations to redshift z11
No full textWe report measurements of the galaxy two-point correlation function at cosmic dawn, using photometrically-selected sources from the JWST Advanced Deep Extragalactic Survey (JADES). The JWST/NIRCam dataset comprises approximately photometrically-selected Lyman Break Galaxies (LBGs), spanning in the redshift range , finding a galaxy bias for the sample at . The result suggests that the observed sources are hosted by dark matter halos of approximately , in broad agreement with theoretical and numerical modelling of early galaxy formation during the epoch of reionization. Furthermore, the JWST JADES dataset enables an unprecedented investigation of clustering of dwarf galaxies two orders of magnitude fainter than the characteristic luminosity (i.e. with ) during the late stages of the epoch of reionization at . By analyzing clustering as a function of luminosity, we find that aligns with previous results for brighter galaxies and then decreases with , as theoretically expected for fainter candidates. These initial results demonstrate the potential for further quantitative characterisation of the interplay between assembly of dark matter and light during cosmic dawn that the growing samples of JWST observations are enabling.MNRAS accepted; 8 pages, 4 figure
Euclid preparation. The Cosmic Dawn Survey (DAWN) of the Euclid Deep and Auxiliary Fields
No full textInternational audienceEuclid will provide deep NIR imaging to 26.5 AB magnitude over 59 deg in its deep and auxiliary fields. The Cosmic DAWN survey complements the deep Euclid data with matched depth multiwavelength imaging and spectroscopy in the UV--IR to provide consistently processed Euclid selected photometric catalogs, accurate photometric redshifts, and measurements of galaxy properties to a redshift of . In this paper, we present an overview of the survey, including the footprints of the survey fields, the existing and planned observations, and the primary science goals for the combined data set
Euclid preparation:The Cosmic Dawn Survey (DAWN) of the Euclid Deep and Auxiliary Fields
No full textEuclid will provide deep NIR imaging to 26.5 AB magnitude over 59 deg in its deep and auxiliary fields. The Cosmic DAWN survey complements the deep Euclid data with matched depth multiwavelength imaging and spectroscopy in the UV--IR to provide consistently processed Euclid selected photometric catalogs, accurate photometric redshifts, and measurements of galaxy properties to a redshift of . In this paper, we present an overview of the survey, including the footprints of the survey fields, the existing and planned observations, and the primary science goals for the combined data set
Strategies for improving early detection and diagnosis of neovascular age-related macular degeneration
No full textTreatment of the neovascular form of age-related macular degeneration (AMD) has been revolutionized by the introduction of such agents as ranibizumab, bevacizumab, and aflibercept. As a result, the incidence of legal blindness occurring secondary to AMD has fallen dramatically in recent years in many countries. While these agents have undoubtedly been successful in reducing visual impairment and blindness, patients with neovascular AMD typically lose some vision over time, and often lose the ability to read, drive, or perform other important activities of daily living. Efforts are therefore under way to develop strategies that allow for earlier detection and treatment of this disease. In this review, we begin by providing an overview of the rationale for, and the benefits of, early detection and treatment of neovascular AMD. To achieve this, we begin by providing an overview of the pathophysiology and natural history of choroidal neovascularization, before reviewing the evidence from both clinical trials and "real-world" outcome studies. We continue by highlighting an area that is often overlooked: the importance of patient education and awareness for early AMD detection. We conclude the review by reviewing an array of both established and emerging technologies for early detection of choroidal neovascularization, ranging from Amsler chart testing, to hyperacuity testing, to advanced imaging techniques, such as optical coherence tomography
Dust at the Cosmic Dawn
No full textObservations provided by the Hubble Space Telescope (HST) and James Webb Space Telescope (JWST) have revealed a surprising abundance of galaxies at the “cosmic dawn” epoch, z>7. Some of them are found even in a more distant universe at z ≃ 14–16. Most of these galaxies appear to be intriguing: they are found to be either super-bright in the rest-frame ultraviolet (UV) band or super-dusty with a heavily reddened stellar population. The transition from the super-bright and super-dusty regimes seems to occur in the redshift range from z∼10.5 to z∼9.5 within a time range of ∼50 Myr. If confirmed, then the origin of this transition is far from being clear. In the review, we discuss possible mechanisms that can make z>10 galaxies free of dust and also explain the origin of apparently excessive dust in galaxies at intermediate and lower redshifts z<10
Efficient Jacobian-Based Inverse Kinematics With Sim-to-Real Transfer of Soft Robots by Learning
No full textThis article presents an efficient learning-based method to solve the <italic>inverse kinematic</italic> (IK) problem on soft robots with highly nonlinear deformation. The major challenge of efficiently computing IK for such robots is due to the lack of analytical formulation for either forward or inverse kinematics. To address this challenge, we employ neural networks to learn both the mapping function of forward kinematics and also the Jacobian of this function. As a result, Jacobian-based iteration can be applied to solve the IK problem. A sim-to-real training transfer strategy is conducted to make this approach more practical. We first generate a large number of samples in a simulation environment for learning both the kinematic and the Jacobian networks of a soft robot design. Thereafter, a sim-to-real layer of differentiable neurons is employed to map the results of simulation to the physical hardware, where this sim-to-real layer can be learned from a very limited number of training samples generated on the hardware.Green Open Access added to TU Delft Institutional Repository ‘You share, we take care!’ – Taverne project https://www.openaccess.nl/en/you-share-we-take-care Otherwise as indicated in the copyright section: the publisher is the copyright holder of this work and the author uses the Dutch legislation to make this work public.Materials and ManufacturingMechatronic Desig
Alpha particle spectroscopy using FNTD and SIM super-resolution microscopy
No full textStructured illumination microscopy (SIM) for the imaging of alpha particle tracks in fluorescent nuclear track detectors (FNTD) was evaluated and compared to confocal laser scanning microscopy (CLSM). FNTDs were irradiated with an external alpha source and imaged using both methodologies. SIM imaging resulted in improved resolution, without increase in scan time. Alpha particle energy estimation based on the track length, direction and intensity produced results in good agreement with the expected alpha particle energy distribution. A pronounced difference was seen in the spatial scattering of alpha particles in the detectors, where SIM showed an almost 50% reduction compared to CLSM. The improved resolution of SIM allows for more detailed studies of the tracks induced by ionising particles. The combination of SIM and FNTDs for alpha radiation paves the way for affordable and fast alpha spectroscopy and dosimetry. Journal compilatio
A simple disc wind model for broad absorption line quasars
No full textApproximately 20 per cent of quasi-stellar objects (QSOs) exhibit broad, blue-shifted absorption lines in their ultraviolet spectra. Such features provide clear evidence for significant outflows from these systems, most likely in the form of accretion disc winds. These winds may represent the ‘quasar’ mode of feedback that is often invoked in galaxy formation/evolution models, and they are also key to unification scenarios for active galactic nuclei (AGN) and QSOs. To test these ideas, we construct a simple benchmark model of an equatorial, biconical accretion disc wind in a QSO and use a Monte Carlo ionization/radiative transfer code to calculate the ultraviolet spectra as a function of viewing angle. We find that for plausible outflow parameters, sightlines looking directly into the wind cone do produce broad, blue-shifted absorption features in the transitions typically seen in broad absorption line (BAL) QSOs. However, our benchmark model is intrinsically X-ray weak in order to prevent overionization of the outflow, and the wind does not yet produce collisionally excited line emission at the level observed in non-BAL QSOs. As a first step towards addressing these shortcomings, we discuss the sensitivity of our results to changes in the assumed X-ray luminosity and mass-loss rate, Ṁwind. In the context of our adopted geometry, Ṁwind ∼ Ṁacc is required in order to produce significant BAL features. The kinetic luminosity and momentum carried by such outflows would be sufficient to provide significant feedback
Cosmic Radio Background from Primordial Black Holes at Cosmic Dawn
No full textThe presence of an extra radio background besides the cosmic microwave
background has important implications for the observation of the 21-cm signal
during the cosmic Dark Ages, Cosmic Dawn, and epoch of Reionization. The strong
absorption trough found in the 21-cm global spectrum measured by the EDGES
experiment, which has a much greater depth than the standard model prediction,
has drawn great interest to this scenario, but more generally it is still of
great interest to consider such a cosmic radio background (CRB) in the early
Universe. To be effective in affecting the 21-cm signal at early time, such a
radio background must be produced by sources which can emit strong radio
signals but modest amount of X-rays, so that the gas is not heated up too
early. We investigate the scenario that such a radio background is produced by
the primordial black holes (PBHs). For PBH with a single mass, we find that if
the PBHs' abundance (ratio of total PBH mass density to
total matter density) and mass satisfy the relation for , and have jet emission, they can generate
a CRB required for reproducing the 21-cm absorption signal seen by the EDGES.
The accretion rate can be boosted if the PBHs are surrounded by dark matter
halos, which permits lower value to satisfy the EDGES
observation. In the latter scenario, since the accretion rate can evolve
rapidly during the Cosmic Dawn, the frequency (redshift) and depth of the
absorption trough can determine the mass and abundance of the PBHs
simultaneously. For absorption trough redshift 17 and depth
mK, it corresponds to and .Comment: 16 pages, 13 figures, accepted for publication in PR
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