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Host: Miguel ABSTRACT TITLE: Particle versus Wave Dark Matter in Deep Space Data from JWST SPEAKER: Tom Broadhurst (UPV/EHU) ABSTRACT: We have discovered in that lensed galaxies intersected by Creation of an inflationary universe out of a black hole TITLE: Role of Stellar Microlensing in Generating Cluster Gravitationally-Lensed Transients The polyhomogeneity of the gravitational field and conserved ABSTRACT: Geodesic Completeness in General Cosmological Scenarios, by William Kinney, Univ. of Buffalo, US. ABSTRACT: Do Black Holes have Singularities? https://arxiv.org/abs/2312.00841 Microsoft Teams ¿Necesita ayuda? TITLE: Solitons in Quantum Field Theory
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June 2024
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Einstein rings are continuously twinkling in deep JWST images. This is caused when
micro-lensing caustics of stars in the lensing galaxy sweep over the surface of
individual stars within the lensed galaxy, allows us to detect individual stars at
cosmological distances apparently switching on and off.
These detections we find favour the inner edge of the Einstein ring with a
broad asymmetric spread that we show is characteristic of Wave Dark Matter as
a Bose Einstein Condensate, of very light axions, 10^{-22}eV, with a de Broglie
wavelength on astronomical scales and motivated by String Theory. Conventional
heavy particle Dark Matter (CDM) predicts the opposite behaviour and appears
excluded. This conclusion is now reinforced by the tendency for the most distant
galaxies to be elongated in shape in JWST images of well resolved high redshift
galaxies. Our cosmological simulations show this effect can be explained
by Wave and Warm Dark Matter, where galaxies form steadily at the nodes of long smooth
filaments as dark matter, stars and gas rain down for an extended period of about 0.5Gyrs.
This is quite unlike CDM where galaxies form from fragmented filaments and frequently merge, so that young galaxy shapes are expected to be oblate spheroids, in tension the observed young galaxies at high redshift observed by JWST. We outline further definitive predictions for comparison with ongoing JWST surveys.
https://arxiv.org/abs/1601.03929
SPEAKER: Sung Kei Li (University of Hong Kong)
ABSTRACT:
This seminar focuses on the impact of stellar microlensing on transients composed of lensed young star clusters, specifically H-II regions,
within the renowned ”Dragon Arc.” The Dragon Arc is an actively star-forming galaxy at a redshift of ∼ 0.73, multiply-lensed by the foreground
galaxy cluster Abell 370. During the Flashlights” project, two deep observations of Abell 370 taken roughly a year apart revealed brightness
variations spatially coinciding with the young star clusters in the Dragon Arc. Unlike conventional transients, where a single stellar source
remains consistently undetectable, these young star cluster transients, comprising numerous stars, persist over time, and the precise effects
of stellar microlensing remains understudied.
By employing a newly developed simulation, we examine the role of stellar microlensing in generating lensed star cluster transients. The simulation
predicts a detection rate of lensed star cluster transients that aligns with the observed data within a 1σ uncertainty range, suggesting that stellar
microlensing alone can account for all the detected lensed star cluster transients. Furthermore, this consistency enables the imposition of constraints
on the abundance of primordial black holes in dark matter, reaching a confidence level of 3σ, with constraints as stringent as ≤ 1%.
charges at null infinity, by Edgar Gasperín, CENTRA (Lisbon)
In this talk we will give an overview of the conformal Einstein field equations (CEFEs) and briefly discuss some of
the global non-linear stability results obtained with the CEFEs in asymptotically flat and de-Sitter-like spacetimes.
Motivated the caveats that emerge from these results, we will discuss the problem at spatial infinity and its impact
(polyhomogeneity) on the peeling behaviour of the gravitational field. To give a simple but illustrative discussion of
the so-called cylinder at spatial infinity (i^0), we will focus the analysis on the polyhomogeneity of spin-0 fields in
Minkowski spacetime propagating close to the cylinder at i^0 and the calculation of conserved charges at the critical
sets where spatial and null infinity meet.
The well-known Borde-Guth-Vilenkin Theorem shows that inflationary spacetimes are generically
geodesically past-incomplete, necessitating the existence of a pre-inflationary boundary of some sort, possibly singular.
In this talk, I discuss the generalization of the BGV theorem to spactimes beyond inflation, including inhomogeneous
and cyclic models. I argue that the cyclic model proposed by Ijjas and Steinhardt is geodesically incomplete, and that
an asymptotically de Sitter version of Penrose’s Conformal Cyclic Cosmology is either past- or future-incomplete.
July 2024
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Unirse a la reunión ahora
Id. de reunión: 337 116 539 27
Código de acceso: kgQJzY
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Unirse en un dispositivo de videoconferencia
Clave de inquilino: teams@tecnalia.com
Id. del vídeo: 127 553 223 3
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Para organizadores: Opciones de la reunión
SPEAKER: Jarah Evslin, Institute of Modern Physics, China
ABSTRACT:
Solitons in quantum field theory correspond to states. We present a new formalism for treating
these states. The formalism is much simpler and easier to use than previous formalisms, making many
previously impractical problems now practical. We have used it to calculate soliton masses, spectra, form factors,
and scattering amplitudes, as well as the decay rates of excited solitons. Our long-term goal is to treat the
monopoles whose condensation may be responsible for confinement in QCD.
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