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Massimo Meneghetti (INAF)14/11/2024, 09:05
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Gregor Rihtaršič (University of Ljubljana)14/11/2024, 09:50Contributed talk
The James Webb Space Telescope is revolutionizing the field of strong gravitational lensing in galaxy clusters, allowing us to go further and fainter in our search for multiply imaged galaxies. I will present the recent results of the Canadian NIRISS Unbiased Cluster Survey (CANUCS), targeting 5 massive clusters with 3 instruments onboard JWST. With the example of MACS 0416 - the cluster with...
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Asmaa Mazoun (Technische Universität München (TUM))14/11/2024, 10:10Contributed talk
In this talk, I will discuss how gravitational weak lensing data can be leveraged to calibrate the masses of galaxy clusters. The South Pole Telescope (SPT) survey detects clusters via the thermal Sunyaev-Zel'dovich (SZ) effect, but this method does not yield direct mass measurements. Gravitational weak lensing provides a complementary approach, enabling accurate mass estimations that are...
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Sijin Chen (LMU Munich)14/11/2024, 11:00Contributed talk
CMB observations show that early density fluctuations were nearly Gaussian. The gravitational evolution of matter formed large structures, and nonlinear evolution introduced non-Gaussianity, making it challenging to analyze. In this project, we employ the scattering transform, a powerful statistical tool that shares ideas with convolutional neural networks (CNNs) but requires no training or...
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Mehar Chawla14/11/2024, 11:20Contributed talk
Higher-order WL statistics can capture the non-Gaussian nature of the Cosmic Web and exploit that to offer stricter constraints on Cosmological/MG parameters. In this talk I will start by elaborating on the significance and advantages of looking into these higher-order statistics.
There are certain known systematic errors (like galaxy Intrinsic Alignment) that exist in WL data, which need...
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Chris Davies (USM LMU)14/11/2024, 11:40Contributed talk
Maximising the information that can be extracted from weak lensing measurements is a key goal for LSST and Euclid. This is typically achieved through statistics that are complementary to the cosmic shear two-point correlation function.
In this talk I will present the development of two such complementary statistics.
The first is weak lensing peaks. Typically, only the peak abundance is...
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Xu Han (LMU Munich)14/11/2024, 12:00Contributed talk
Cosmic voids are vast underdense regions in the universe that offer unique insights into dark energy and the large-scale structure of the cosmos. This talk presents a novel method for identifying voids in weak lensing convergence maps using a 2D watershed algorithm. By analyzing data from the CosmoGridV1 simulation and the Dark Energy Survey (DES), we demonstrate the algorithm's capability to...
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Willem de Roo14/11/2024, 12:20Contributed talk
The International LOFAR Telescope (ILT) is currently observing the entire northern sky at a resolution of 0.3 arcsec as part of the LOFAR Two-metre Sky Survey (LoTSS). Its large survey area and high resolution combined with steep number counts towards low frequencies make the ILT well suited for finding galaxy-scale lenses, but the inherent complexity of radio source morphologies make the...
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Leon Roman Ecker (LMU Munich (USM)/ Max-Planck Institute for extraterrestrial physics (MPE))14/11/2024, 14:10Contributed talk
The Euclid mission is expected to discover approximately 150,000 strong gravitational lenses, greatly expanding the known lens population (Collett et al. 2015). Low-redshift early-type galaxies (ETGs) offer a unique opportunity to probe the stellar initial mass function (IMF) as their Einstein radii, typically smaller than the effective radius, enable mass measurements more sensitive to...
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Han Wang (MPA/TUM)14/11/2024, 14:30Contributed talk
We present a mass measurement for the secondary lens along the line of sight (LoS) in the multi-plane strong lens modeling of the group-scale lens CASSOWARY 31 (CSWA 31). The secondary lens at redshift z = 1.49 is a spiral galaxy well aligned along the LoS with the main lens at z = 0.683. Using the MUSE integral-field spectroscopy of this spiral galaxy, we measure its rotation velocities and...
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Allan Schweinfurth (TUM / MPA)14/11/2024, 14:50Contributed talk
Strong gravitational lensing is an astrophysical effect that happens when the gravitational field of a massive object bends light from a background source, creating multiple, often distorted, images of the same distant object. Accurate modelling of the mass distribution of strong gravitational lenses is crucial in order to use them as astrophysical and cosmological probes, such as for...
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Maryam Tajalli (Max Planck Institute for Astrophysics)14/11/2024, 15:10Contributed talk
Strong gravitational lensing has proven to be a promising tool for detecting low-mass haloes through observing perturbations in the lensing potential, therefore allowing the testing of different dark matter (DM) models by comparing the theoretical predictions for the abundance of such haloes in different DM models with observations. However, to robustly constrain the mass function of low-mass...
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Noemi Anau Montel (MPA)14/11/2024, 15:30
Galaxy-galaxy strong gravitational lenses provide a unique laboratory for probing small-scale structures and testing the $\Lambda$CDM paradigm. However, performing precise statistical analysis of such observations is extremely challenging since it requires disentangling the source galaxy’s light from the lens’ mass distribution and marginalizing over different dark matter substructure...
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David Gebauer (LMU Munich)14/11/2024, 16:10Contributed talk
We present a simulation-based inference analysis framework for a higher-order weak lensing observable called the integrated 3-point correlation function. For this we have created a forward model based on N-body simulations. This forward model can create realistic shear maps including survey masks, realistic shape noise, and relevant systematic effects. Furthermore, I present a Python package...
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Benjamin Holzschuh14/11/2024, 16:30Contributed talk
We present a foundation model for strong lensing based on diffusion transformers, which can solve a wide range of different simulation-based inference problems via representation learning. Image-like data such as observations are split into smaller patches, which together with their positions are embedded as tokens. Similarly, parametric models are also encoded via tokens. A strong lens system...
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Alejandra Melo Melo (Max Planck Institute for Astrophysics / Technical University of Munich)14/11/2024, 16:50Contributed talk
In the past, researchers have relied on single-resolution images from individual telescopes to detect gravitational lenses. We propose a search for galaxy-galaxy lenses that, for the first time, combines high-resolution single-band images (in our case Hubble Space Telescope, HST) with low-resolution multi-band images (in our case Legacy survey, LS) using machine learning. To compensate for the...
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Stefan Taubenberger (TUM / MPA)14/11/2024, 17:10Contributed talk
Strongly lensed supernovae (SNe) hold great promise for measuring the expansion rate of the Universe and studying SN progenitors and environments. However, finding lensed SNe resembles searching for the needle in a haystack, and following them up is very demanding and costly due to their faintness. For the best possible use of available resources, it is thus essential that we can securely...
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Jana Grupa (Max Planck Institute for Astrophysics)14/11/2024, 17:30Contributed talk
With the upcoming start of Rubin Observatory Legacy Survey of Space and Time
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(LSST), we expect to detect hundreds to thousands of strongly lensed supernovae,
which can be used for time-delay cosmography.
As part of the HOLISMOKES program, we focus on developing methods to measure time delays of strongly lensed type II supernovae (SNe II) to determine the Hubble Constant.
In my talk, I... -
Elias Mamuzic (Technical University of Munich / Max Planck Institute for Astrophysics)14/11/2024, 17:50
In the coming years, surveys such as Rubin Observatory Legacy Survey of Space and Time (LSST) are expected to increase the number of observed tidal disruption events (TDEs) substantially. This analysis is a followup to Szekerczes, et al. (2024). We similarly employ Monte Carlo integration to calculate the TDE rate as a function of limiting magnitude. We investigate multiple black hole mass...
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