A5024423912- Galaxies: Formation, Evolution, Phenomena
- Astrophysics and Cosmic Phenomena
- Astronomy and Astrophysical Research
- Radio Astronomy Observations and Technology
- Astrophysical Phenomena and Observations
- Neutrino Physics Research
- Astrophysics and Star Formation Studies
- Dark Matter and Cosmic Phenomena
- Stellar, planetary, and galactic studies
- Cosmology and Gravitation Theories
- Ionosphere and magnetosphere dynamics
- Gamma-ray bursts and supernovae
- Solar and Space Plasma Dynamics
- Adaptive optics and wavefront sensing
- Particle Detector Development and Performance
- Magnetic confinement fusion research
- Digital Radiography and Breast Imaging
- Earthquake Detection and Analysis
- Advanced X-ray and CT Imaging
- Geophysics and Gravity Measurements
- Scientific Research and Discoveries
- Advanced Optical Sensing Technologies
- Computational Physics and Python Applications
- Atomic and Subatomic Physics Research
- Quantum, superfluid, helium dynamics
Heidelberg Institute for Theoretical Studies
2016-2022
Heidelberg University
2011-2022
University of Geneva
2011-2018
Swiss Institute of Comparative Law
2013
We present a joint optical/X-ray analysis of the massive galaxy cluster Abell 2744 (z=0.308). Our strong- and weak-lensing within central region cluster, i.e., at R<1Mpc from brightest galaxy, reveals eight substructures, including main core. All these dark-matter halos are detected with significance least 5sigma feature masses ranging 0.5 to 1.4x10^{14}Msun R<150kpc. Merten et al. (2011) Medezinski (2016) substructures also by us. measure slightly higher mass for core component than...
The Beyond Ultra-deep Frontier Fields and Legacy Observations (BUFFALO) is a 101 orbit + parallel Cycle 25 Hubble Space Telescope Treasury program taking data from 2018-2020. BUFFALO will expand existing coverage of the (HFF) in WFC3/IR F105W, F125W, F160W ACS/WFC F606W F814W around each six HFF clusters flanking fields. This additional area has not been observed by HST but already covered deep multi-wavelength datasets, including Spitzer Chandra. As with original program, designed to take...
We present a self-consistent interpretation of the very-high-energy neutrino signal from direction inner Galaxy, which is part astronomical reported by IceCube. demonstrate that an estimate flux in E>100 TeV energy range lies at high-energy power-law extrapolation spectrum diffuse gamma-ray emission Galactic Ridge, as observed Fermi telescope. This suggests IceCube and Fermi/LAT fluxes are both produced interactions cosmic rays with interstellar medium Norma arm and/or Bar. Cosmic...
Galaxy clusters are the endpoints of structure formation and continuously growing through merging accretion smaller structures. Numerical simulations predict that a fraction their energy content is not yet thermalized, mainly in form kinetic motions (turbulence, bulk motions). Measuring level non-thermal pressure support necessary to understand processes leading virialization gas within potential well main halo calibrate biases hydrostatic mass estimates. We present high-quality measurements...
Observations in radio have shown that galaxy clusters are giant reservoirs of cosmic rays (CR). Although a gamma- ray signal from the cluster volume is expected to arise through interactions CR protons with ambient plasma, confirming observation still missing. We search for cumulative gamma-ray emission direction by analysing collection stacked Fermi-LAT count maps. Additionally, we investigate possible systematic differences between cool-core and non-cool core populations. Making use sample...
Radio relics are Mpc-scale diffuse radio sources at the peripheries of galaxy clusters which thought to trace outgoing merger shocks. We present XMM-Newton and Suzaku observations cluster Abell 2744 (z=0.306), reveal presence a shock front 1.5 Mpc East core. The surface-brightness jump coincides with position known relic. Although indicates weak Mach number $\mathcal{M}=1.7_{-0.3}^{+0.5}$, plasma in post-shock region has been heated very high temperature ($\sim13$ keV) by passage wave. low...
Context. Galaxy clusters are continuously growing through the accretion of matter in their outskirts. This process induces inhomogeneities gas density distribution (clumping) which need to be taken into account recover physical properties intracluster medium (ICM) at large radii. Aims. We studied thermodynamic outskirts (R > R500) massive galaxy cluster Abell 2142 by combining Sunyaev Zel'dovich (SZ) effect with X-ray signal. Methods. combined SZ pressure profile measured Planck XMM-Newton...
Galaxy clusters are thought to grow hierarchically through the continuous merging and accretion of smaller structures across cosmic time. In local Universe, these phenomena still active in outer regions massive ($R>R_{500}$), where matter distribution is expected become clumpy asymmetric because presence accreting structures. We present XMM-Newton Cluster Outskirts Project (X-COP), which targets a sample 13 ($M_{500}>3\times10^{14}M_\odot$) redshift range 0.04-0.1 at uniform depth. The was...
Context. The imaging and timing properties of {\gamma}-ray emission from electromagnetic cascades initiated by very-high-energy (VHE) {\gamma}-rays in the intergalactic medium depend on strength B correlation length {\lambda}B magnetic fields (IGMF). Aims. We study possibility measuring both via observations cascade with telescopes. Methods. For each measurement method, we find two characteristics signal, which are sensitive to IGMF values different combinations. case using observation...
We explore the detectability of neutrino flux from entire Galactic Plane or a part it with IceCube. calculate normalization and spectral index power law spectrum different regions plane, based on observed characteristics pion decay gamma-ray diffuse emission by Fermi/LAT telescope in energy band above 100 GeV. compare calculated this way sensitivity IceCube for detection extended sources. Assuming binned source analysis method, we find that only possible evidence sources located Northern...
Context: Hadronic models, involving matter (proton or nuclei) acceleration in blazar jets, imply high energy photon and neutrino emissions due to interactions of high-energy protons with and/or radiation the source environment. Aims: This paper shows that sensitivity IceCube telescope its 40-string configuration (IC-40) is already at level constraining parameter space purely hadronic scenarios activity blazars. Methods: Assuming entire power originates from interactions, assuming models...
The hot electrons in the intra-cluster medium produce a spectral distorsion of cosmic microwave background (CMB) black body emission, thermal Sunyaev-Zel'dovich effect (tSZ). This characteristic is now commonly used to detect and characterize properties galaxy clusters. tSZ does not depends on redshift, only slightly affected by cluster via relativistic corrections, when reach velocities. present work proposes linear component separation approach extract Compton parameter corrections for...
Context. Biases in mass measurements of galaxy clusters are one the major limiting systematics constraining cosmology with clusters. Aims. We aim to demonstrate that associated cluster gravitational potentials smaller than hydrostatic bias and could therefore be a good alternative masses cosmological studies. Methods. Using simulations clusters, we compute biases (HE mass) those potential, reconstructed from at X-ray millimeter wavelengths. In particular, investigate effects presence...
Context. Galaxy clusters can be used as cosmological probes, but to this end, they need thoroughly understood. Combining all cluster observables in a consistent way will help us understand their global properties and internal structure. Aims. We provide proof of the concept that projected gravitational potential galaxy directly reconstructed from X-ray observations. also show joint analysis locally test validity equilibrium assumptions clusters. Methods. newly developed reconstruction...
Accounting for the triaxial shapes of galaxy clusters will become important in context upcoming cosmological surveys. We show that, compared to gas density distribution, cluster gravitational potential can be better characterised by a simple 3D model and is more robust against fluctuations. Perturbations distribution have substantial influence on derived thermodynamic properties, while potentials are smooth well-approximated spheroidal model. use statistical sample 85 from large...
The mass of galaxy clusters is not a direct observable, nonetheless it commonly used to probe cosmological models. Based on the combination all main cluster observables, that is, X-ray emission, thermal Sunyaev-Zel'dovich (SZ) signal, velocity dispersion galaxies, and gravitational lensing, potential can be jointly reconstructed. We derive two ingredients required for this joint reconstruction: potentials individually reconstructed from observables their covariance matrices, which act as...
Context . Galaxy clusters provide a multitude of observational data across wavelengths, and their structure morphology are considerable interest in cosmology as well astrophysics. Aims We develop framework that allows the combination lensing non-lensing observations free-form mesh-free approach to infer projected mass distribution individual galaxy clusters. This method can be used test common assumptions on parametric models. Methods make use reconstruction code S A WL ENS 2, expand its...