A5022611236- Galaxies: Formation, Evolution, Phenomena
- Astronomy and Astrophysical Research
- Stellar, planetary, and galactic studies
- Gamma-ray bursts and supernovae
- Adaptive optics and wavefront sensing
- Astrophysical Phenomena and Observations
- Astrophysics and Star Formation Studies
- Pulsars and Gravitational Waves Research
- Astrophysics and Cosmic Phenomena
- Astronomical Observations and Instrumentation
- Cosmology and Gravitation Theories
- Radio Astronomy Observations and Technology
- Aerospace Engineering and Energy Systems
- Calibration and Measurement Techniques
- History and Developments in Astronomy
- Photocathodes and Microchannel Plates
- CCD and CMOS Imaging Sensors
- Scientific Research and Discoveries
- Dark Matter and Cosmic Phenomena
- Atmospheric Ozone and Climate
- Spacecraft and Cryogenic Technologies
- Geophysics and Gravity Measurements
- Astro and Planetary Science
- Cryospheric studies and observations
- Spacecraft Design and Technology
Durham University
2016-2025
University of KwaZulu-Natal
2016-2025
Centre National de la Recherche Scientifique
2009-2024
Aix-Marseille Université
2009-2024
University of the Witwatersrand
2024
Space Telescope Science Institute
2016-2024
Laboratoire d’Astrophysique de Marseille
2010-2023
Indiana Cancer Consortium
2018-2023
École Polytechnique Fédérale de Lausanne
2017-2021
Durham Technical Community College
2019
Extending over three Hubble Space Telescope (HST) cycles, the Frontier Fields (HFF) initiative constitutes largest commitment ever of HST time to exploration distant Universe via gravitational lensing by massive galaxy clusters. Here, we present models mass distribution in six HFF cluster lenses, derived from a joint strong- and weak-lensing analysis anchored total 88 multiple-image systems identified existing data. The resulting maps projected magnification effectively calibrate clusters as...
We use deep Hubble Space Telescope imaging of the Frontier Fields to accurately measure galaxy rest-frame ultraviolet luminosity function (UV LF) in redshift range z ∼ 6–8. combine observations three lensing clusters, A2744, MACS 0416, and 0717, their associated parallel fields select high-redshift dropout candidates. latest models estimate flux magnification effective survey volume combination with completeness simulations performed source plane. report detection 227 candidates at = 6–7 25...
The gravitationally lensed supernova Refsdal appeared in multiple images produced through gravitational lensing by a massive foreground galaxy cluster. After the 2014, lens models of cluster predicted that an additional image would appear 2015, which was subsequently observed. We use time delays between to perform blinded measurement expansion rate Universe, quantified Hubble constant (
The Euclid ERO showcase Euclid's capabilities in advance of its main mission by targeting 17 astronomical objects, including galaxy clusters, nearby galaxies, globular and star-forming regions. A total 24 hours observing time was allocated the early months operation, scientific community engaged through an public data release. We describe development pipeline to create visually compelling images while simultaneously meeting demands within launch leveraging a pragmatic data-driven strategy....
Galaxy cluster Abell 3827 hosts the stellar remnants of four almost equally bright elliptical galaxies within a core radius 10kpc. Such corrugation distribution is very rare, and suggests recent formation by several simultaneous mergers. We map associated dark matter, using new Hubble Space Telescope imaging VLT/MUSE integral field spectroscopy gravitationally lensed system threaded through core. find that each central retains matter halo, but (at least) one these spatially offset from its...
We present a high-precision mass model of galaxy cluster Abell 2744, based on strong gravitational-lensing analysis the Hubble Space Telescope Frontier Fields (HFF) imaging data, which now include both Advanced Camera for Surveys and Wide Field 3 observations to final depth. Taking advantage unprecedented depth visible near-infrared we identify 34 new multiply imaged galaxies, bringing total 61, comprising 181 individual lensed images. In process, correct previous erroneous identifications...
We present a high-precision mass model of the galaxy cluster MACSJ0416.1-2403, based on strong-gravitational-lensing analysis recently acquired Hubble Space Telescope Frontier Fields (HFF) imaging data. Taking advantage unprecedented depth provided by HST/ACS observations in three passbands, we identify 51 new multiply imaged galaxies, quadrupling previous census and bringing grand total to 68, comprising 194 individual lensed images. Having selected subset 57 most securely identified use...
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...
Exploiting the power of gravitational lensing, Hubble Frontier Fields (HFF) program aims at observing six massive galaxy clusters to explore distant Universe far beyond depth limits blank field surveys. Using complete Space Telescope observations first HFF cluster Abell 2744, we report detection 50 candidates $z \sim 7$ and eight 8$ in a total survey area 0.96 arcmin$^{2}$ source plane. Three these galaxies are multiply-imaged by lensing cluster. an updated model mass distribution were able...
The far-infrared fine-structure line [CII] at 1900.5\,GHz is known to be one of the brightest cooling lines in local galaxies, and therefore it has been suggested an efficient tracer for star-formation very high-redshift galaxies. However, recent results galaxies $z>6$ have yielded numerous non-detections star-forming except quasars submillimeter We report ALMA observations two lensed, $z = 6.029$ $z=6.703$. galaxy A383-5.1 (star formation rate [SFR] 3.2 M$_\odot$ yr$^{-1}$ magnification...
We report the first weak-lensing detection of a large-scale filament funneling matter onto core massive galaxy cluster MACSJ0717.5+3745. Our analysis is based on mosaic 18 multi-passband images obtained with ACS aboard HST, covering an area \sim 10x20 arcmin^2. use pipeline developed for COSMOS survey, modified clusters, to produce catalogue. A mass map then computed by applying weak-gravitational-lensing multi-scale reconstruction technique designed describe irregular distributions such as...
ABSTRACT We present bahamas-SIDM, the first large-volume, $(400 \, h^{-1} \mathrm{\, Mpc})^{3}$, cosmological simulations including both self-interacting dark matter (SIDM) and baryonic physics. These are important for two primary reasons: (1) they include effects of baryons on distribution (2) baryon particles can be used to make mock observables that compared directly with observations. As is well known, SIDM haloes systematically less dense in their centres, rounder, than CDM haloes....
Abstract We test the assumption of hydrostatic equilibrium in an X-ray luminosity selected sample 50 galaxy clusters at 0.15 &lt; z 0.3 from Local Cluster Substructure Survey (LoCuSS). Our weak-lensing measurements M500 control systematic biases to sub-4 per cent, and our same achieve excellent agreement between XMM–Newton Chandra. The mean ratio lensing mass for these is $\mathrel {\beta _{\rm X}}\;= 0.95\pm 0.05$, 44 also detected by Planck, Planck estimate LoCuSS P}}\;= 0.04$. Based...
[abridged] We present a strong-lensing analysis of MACSJ0717.5+3745, based on the full depth Hubble Frontier Field (HFF) observations, which brings number multiply imaged systems to 61, ten are spectroscopically confirmed. The total images comprised in these rises 165. Our uses parametric mass reconstruction technique, as implemented Lenstool software, constrain distribution composed four large-scale components + galaxy-scale perturbers. find superposition cored isothermal provide good fit...
We map the lensing-inferred substructure in first three clusters observed by Hubble Space Telescope Frontier Fields (HSTFF) Initiative: Abell 2744 (z = 0.308), MACSJ 0416, 0.396) and 1149 0.543). Statistically resolving dark matter subhaloes down to |${\sim }10^{9.5}\,{{\rm {M}_{{\odot}}}}$|, we compare derived subhalo mass functions (SHMFs) theoretical predictions from analytical models with numerical simulations a Lambda cold (LCDM) cosmology. Mimicking our observational cluster member...
Motivated by the preponderance of so-called "heavy black holes" in binary hole (BBH) gravitational wave (GW) detections to date, and role that lensing continues play discovering new galaxy populations, we explore possibility GWs are strongly-lensed massive clusters. For example, if one GW sources were actually located at $z=1$, then rest-frame mass associated BHs would be reduced a factor $\sim2$. Based on known populations BBH strong-lensing clusters, estimate conservative lower limit...
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...
The Cluster HEritage project with XMM-Newton - Mass Assembly and Thermodynamics at the Endpoint of structure formation (CHEX-MATE) is a three mega-second Multi-Year Heritage Programme to obtain X-ray observations minimally-biased, signal-to-noise limited sample 118 galaxy clusters detected by Planck through Sunyaev-Zeldovich effect. programme, described in detail this paper, aims study ultimate products time mass. It composed census most recent objects have formed (Tier-1: 0.05 < z 0.2; 2 x...
Abstract Exploiting the fundamentally achromatic nature of gravitational lensing, we present a lens model for massive galaxy cluster SMACS J0723.3−7323 (SMACS J0723; z = 0.388) that significantly improves upon earlier work. Building on strong-lensing constraints identified in prior Hubble Space Telescope (HST) observations, mass utilizes 21 multiple-image systems, 17 which were newly discovered Early Release Observation data from JWST. The resulting maps distribution to an rms spatial...
ABSTRACT The distribution of mass in galaxy-scale strong gravitational lenses is often modelled as an elliptical power-law plus ‘external shear’, which notionally accounts for neighbouring galaxies and cosmic shear along our line sight. A small amount external could come from these sources, but we show that the vast majority does not. Except a handful rare systems, best-fitting values do not correlate with independent measurements line-of-sight shear: weak lensing 45 Hubble Space Telescope...
We present Advanced Camera for Surveys observations of MACS J1149.5+2223, an X-ray luminous galaxy cluster at z = 0.544 discovered by the Massive Cluster Survey. The data reveal least seven multiply imaged galaxies, three which we have confirmed spectroscopically. One these is a spectacular face-on spiral 1.491, four images are gravitationally magnified 8 ≲ μ 23. identify this as L⋆ (MB ≃ −20.7), disk-dominated (B/T 0.5) galaxy, forming stars ∼6 M☉ yr−1. use robust sample galaxies to...
The Herschel Lensing Survey (HLS) will conduct deep PACS and SPIRE imaging of ~40 massive clusters galaxies. strong gravitational lensing power these enable us to penetrate through the confusion noise, which sets ultimate limit on our ability probe Universe with Herschel. Here, we present an overview survey a summary major results from Science Demonstration Phase (SDP) observations Bullet Cluster (z=0.297). SDP data are rich, allowing study not only background high-redshift galaxies (e.g.,...
We present a high-precision mass model of the galaxy cluster MACS J1149.6+ 2223, based on strong gravitational lensing analysis Hubble Space Telescope Frontier Fields (HFF) imaging data and spectroscopic follow-up with Gemini/Gemini Multi-Object Spectrographs (GMOS) Very Large (VLT)/Multi Unit Spectroscopic Explorer (MUSE). Our includes 12 new multiply imaged galaxies, bringing total to 22, composed 65 individual lensed images. Unlike first two HFF clusters, Abell 2744 J0416.1−2403, J1149...