Publications (68)
Extreme magnification of a star at redshift 1.5 by a galaxy-cluster lens
Patrick L. Kelly, Jose M. Diego, Steven Rodney +42
Galaxy-cluster gravitational lenses can magnify background galaxies by a total factor of up to ~50. Here we report an image of an individual star at redshift z=1.49 (dubbed "MACS J…
CLASH: Precise New Constraints on the Mass Profile of Abell 2261
Dan Coe, Keiichi Umetsu, Adi Zitrin +43
We precisely constrain the inner mass profile of Abell 2261 (z=0.225) for the first time and determine this cluster is not "over-concentrated" as found previously, implying a forma…
Projected central dark matter fractions and densities in massive early-type galaxies from the Sloan Digital Sky Survey
Claudio Grillo
We investigate in massive early-type galaxies the variation of their two-dimensional central fraction of dark over total mass and dark matter density as a function of stellar mass,…
Metallicity Scatter Originating from Sub-kiloparsec Starbursting Clumps in the Core of a Protocluster at z=7.88
Takahiro Morishita, Massimo Stiavelli, Eros Vanzella +9
We present new JWST NIRSpec integral field unit (IFU) G395H/F290LP observations of a merging galaxy system at , part of A2744-z7p9, the most distant protocluster to date. T…
The production of ionizing photons in UV-faint z~3-7 galaxies
Gonzalo Prieto-Lyon, Victoria Strait, Charlotte A. Mason +20
The demographics of the production and escape of ionizing photons from UV-faint early galaxies is a key unknown in discovering the primary drivers of reionization. With the advent…
CLASH: Mass Distribution in and around MACS J1206.2-0847 from a Full Cluster Lensing Analysis
Keiichi Umetsu, Elinor Medezinski, Mario Nonino +45
We derive an accurate mass distribution of the galaxy cluster MACS J1206.2-0847 (z=0.439) from a combined weak-lensing distortion, magnification, and strong-lensing analysis of wid…
VLT/MUSE observations of SDSS J1029+2623: towards a high-precision strong lensing model
Ana Acebron, Claudio Grillo, Pietro Bergamini +9
We present a strong lensing analysis of the galaxy cluster SDSS J1029+2623 at , one of the few currently known lens clusters with multiple images of a background ($z=2.199…
VST-GAME: Galaxy Assembly as a function of Mass and Environment with VST. Photometric assessment and density field of MACSJ0416
Nicolas Estrada, Amata Mercurio, Benedetta Vulcani +14
Observational studies have widely demonstrated that galaxy physical properties are strongly affected by the surrounding environment. On one side, gas inflows provide galaxies with…
CLASH-VLT: Constraints on the Dark Matter Equation of State from Accurate Measurements of Galaxy Cluster Mass Profiles
Barbara Sartoris, Andrea Biviano, Piero Rosati +39
A pressureless scenario for the Dark Matter (DM) fluid is a widely adopted hypothesis, despite the absence of a direct observational evidence. According to general relativity, the…
The GLASS-JWST Early Release Science Program. III. Strong lensing model of Abell 2744 and its infalling regions
Pietro Bergamini, Ana Acebron, Claudio Grillo +23
We present a new high-precision, JWST-based, strong lensing model for the galaxy cluster Abell 2744 at . By combining the deep, high-resolution JWST imaging from the GLAS…
Early results from GLASS-JWST. XIV: A spectroscopically confirmed protocluster 650 million years after the Big Bang
Takahiro Morishita, Guido Roberts-Borsani, Tommaso Treu +39
We present the spectroscopic confirmation of a protocluster at behind the galaxy cluster Abell2744 (hereafter A2744-z7p9OD). Using JWST NIRSpec, we find seven galaxies wit…
Enhanced strong-lensing model of MACS~J0138.02155 based on new JWST and VLT/MUSE observations
Ana Acebron, Pietro Bergamini, Piero Rosati +10
We present a new parametric strong lensing analysis of the galaxy cluster MACS J0138.0-2155 at z = 0.336, the first known to show two multiply-imaged supernova (SN) siblings, SN Re…
The puzzling properties of the MACS1149-JD1 galaxy at z=9.11
Massimo Stiavelli, Takahiro Morishita, Marco Chiaberge +6
We analyze new JWST NIRCam and NIRSpec data on the redshift 9.11 galaxy MACS1149-JD1. Our NIRCam imaging data reveal that JD1 comprises three spatially distinct components. Our spe…
Early results from GLASS-JWST. IX: First spectroscopic confirmation of low-mass quiescent galaxies at with NIRISS
Danilo Marchesini, Gabriel Brammer, Takahiro Morishita +20
How passive galaxies form, and the physical mechanisms which prevent star formation over long timescales, are some of the most outstanding questions in understanding galaxy evoluti…
Supernova 2025wny: High-angular resolution Keck/NIRC2 observations and preliminary lens modeling
Christopher J. Storfer, Kenneth C. Wong, Ana Acebron +10
Multiply imaged, gravitationally lensed supernovae are rare but powerful tools for providing independent measurements on cosmological parameters. Supernova (SN) 2025wny ("SN Winny"…
The Low Mass End of the Fundamental Relation for Gravitationally Lensed Star Forming Galaxies at 1<z<6
Lise Christensen, Johan Richard, Jens Hjorth +6
We present VLT/X-shooter spectra of 13 galaxies in the redshift range 1< z < 6, which are strongly lensed by massive galaxy clusters. Spectroscopic redshifts are measured for nine…
Galaxies at the edges: a complete census of MACS J0416.1-2403 cluster
Rossella Ragusa, Maurizio D'Addona, Amata Mercurio +20
Numerous studies have established that the environment influences the physical properties of a galaxy. While gas inflows supply the fuel for SF, high density and temperature condit…
Accelerating lensed quasar discovery and modeling with physics-informed variational autoencoders
Irham T. Andika, Stefan Schuldt, Sherry H. Suyu +5
Strongly lensed quasars provide valuable insights into the rate of cosmic expansion, the distribution of dark matter in foreground deflectors, and the characteristics of quasar hos…
JWST NIRSpec Spectroscopy of the Remarkable Bright Galaxy GHZ2/GLASS-z12 at Redshift 12.34
Marco Castellano, Lorenzo Napolitano, Adriano Fontana +28
We spectroscopically confirm the mag galaxy GHZ2/GLASS-z12 to be at redshift . The source was selected via NIRCam photometry in GLASS-JWST ERS data, p…
Early results from GLASS-JWST. III: Galaxy candidates at z9-15
Marco Castellano, Adriano Fontana, Tommaso Treu +27
We present the results of a first search for galaxy candidates at z9--15 on deep seven-bands NIRCam imaging acquired as part of the GLASS-JWST Early Release Science Program o…
An excess of small-scale gravitational lenses observed in galaxy clusters
Massimo Meneghetti, Guido Davoli, Pietro Bergamini +11
Cold dark matter (CDM) constitutes most of the matter in the Universe. The interplay between dark and luminous matter in dense cosmic environments like galaxy clusters is studied t…
Dynamical models of cluster members to probe the total mass properties of cluster subhalos. I. A comparison with parametric strong lensing models
Nicola Bianchetti, Claudio Grillo, Giovanni Granata +6
In this series of papers, we present dynamical models of cluster members in strong lensing (SL) galaxy clusters to independently probe the persistent discrepancy reported between S…
Improved strong lensing modelling of galaxy clusters using the Fundamental Plane: Detailed mapping of the baryonic and dark matter mass distribution of Abell S1063
Giovanni Granata, Amata Mercurio, Claudio Grillo +6
From Hubble Frontier Fields photometry, and data from the Multi Unit Spectroscopic Explorer on the Very Large Telescope, we build the Fundamental Plane (FP) relation for the early-…
An improved Magellan weak lensing analysis of the galaxy cluster Abell 2744
Davide Abriola, Daniele Della Pergola, Marco Lombardi +4
We present a new weak lensing analysis of the Hubble Frontier Fields galaxy cluster Abell 2744 ( = 0.308) using new Magellan/MegaCam multi-band imaging data. We carry out…
Accelerated Emergence of Evolved Galaxies in Early Overdensities at
Takahiro Morishita, Zhaoran Liu, Massimo Stiavelli +8
We report the identification of two galaxy overdensities at in the sightline of the galaxy cluster Abell 2744. These overdensities consist of 25 and 17 member galaxies,…
Dynamics of the galactic component of Abell S1063 and MACS J1206.20847
Giovanni Ferrami, Giuseppe Bertin, Claudio Grillo +2
The galactic component in clusters is commonly thought to be generally nonrotating and in a dynamical state different from that of a collisionally relaxed system. In practice, a te…
The next step in galaxy cluster strong lensing: modeling the surface brightness of multiply-imaged sources
Ana Acebron, Claudio Grillo, Sherry H. Suyu +12
Overcoming both modeling and computational challenges, we present, for the first time, the extended surface-brightness distribution model of a strongly-lensed source in a complex g…
A luminous and young galaxy at z=12.33 revealed by a JWST/MIRI detection of Hα and [OIII]
Jorge A. Zavala, Marco Castellano, Hollis B. Akins +37
The James Webb Space Telescope (JWST) has discovered a surprising population of bright galaxies in the very early universe (<500 Myrs after the Big Bang) that is hard to explain wi…
Probing ionizing radiation of L<~0.1L* star-forming galaxies at z>~3 with strong lensing
Eros Vanzella, Mario Nonino, Stefano Cristiani +7
We show the effectiveness of strong lensing in the characterisation of Lyman continuum emission from faint L<~0.1L* star-forming galaxies at redshift >~ 3. Past observations of L>~…
Probing coherence in metal absorption towards multiple images of strong gravitationally lensed quasars
Rajeshwari Dutta, Ana Acebron, Michele Fumagalli +3
We present a tomographic analysis of metal absorption lines arising from the circumgalactic medium (CGM) of galaxies at z~0.5-2, using Multi Unit Spectroscopic Explorer (MUSE) obse…
Early results from GLASS-JWST. II: NIRCam extra-galactic imaging and photometric catalog
Emiliano Merlin, Andrea Bonchi, Diego Paris +26
We present the reduced images and multi-wavelength catalog of the first JWST NIRCam extra-galactic observations from the GLASS Early Release Science Program, obtained as coordinate…
CLASH-X: A Comparison of Lensing and X-ray Techniques for Measuring the Mass Profiles of Galaxy Clusters
Megan Donahue, G. Mark Voit, Andisheh Mahdavi +35
We present profiles of temperature (Tx), gas mass, and hydrostatic mass estimated from new and archival X-ray observations of CLASH clusters. We compare measurements derived from X…
Early results from GLASS-JWST. XX: Unveiling a population of "red-excess'' galaxies in Abell2744 and in the coeval field
Benedetta Vulcani, Tommaso Treu, Antonello Calabro +26
We combine JWST/NIRCam imaging and MUSE data to characterize the properties of galaxies in different environmental conditions in the cluster Abell2744 () and in its immed…
The nature of an ultra-faint galaxy in the cosmic Dark Ages seen with JWST
Guido Roberts-Borsani, Tommaso Treu, Wenlei Chen +44
In the first billion years after the Big Bang, sources of ultraviolet (UV) photons are believed to have ionized intergalactic hydrogen, rendering the Universe transparent to UV rad…
A Brightest Cluster Galaxy with an Extremely Large Flat Core
Marc Postman, Tod R. Lauer, Megan Donahue +14
Hubble Space Telescope images of the galaxy cluster Abell 2261, obtained as part of the Cluster Lensing And Supernova survey with Hubble, show that the brightest galaxy in the clus…
Dissecting the Interstellar Media of A Wolf-Rayet Galaxy at
Takahiro Morishita, Massimo Stiavelli, Stefan Schuldt +1
We report JWST/NIRSpec observations of a star-forming galaxy at , MACSJ1149-WR1. We securely detect two temperature-sensitive auroral lines, [SIII]6312 (7.4) and [OII]7…
Gravitationally Lensed Galaxies at 2<z<3.5: Direct Abundance Measurements of Lya Emitters
Lise Christensen, Peter Laursen, Johan Richard +6
Strong gravitational lensing magnifies the flux from distant galaxies, allowing us to detect emission lines that would otherwise fall below the detection threshold for medium-resol…
CLASH: Weak-Lensing Shear-and-Magnification Analysis of 20 Galaxy Clusters
Keiichi Umetsu, Elinor Medezinski, Mario Nonino +21
We present a joint shear-and-magnification weak-lensing analysis of a sample of 16 X-ray-regular and 4 high-magnification galaxy clusters at 0.19<z<0.69 selected from the Cluster L…
A persistent excess of galaxy-galaxy strong lensing observed in galaxy clusters
Massimo Meneghetti, Weiguang Cui, Elena Rasia +18
Previous studies have revealed that the estimated probability of galaxy-galaxy strong lensing in observed galaxy clusters exceeds the expectations from the Cold Dark Matter co…
HOLISMOKES XIX: SN 2025wny at , the first strongly lensed superluminous supernova
Stefan Taubenberger, Ana Acebron, Raoul Cañameras +45
We present imaging and spectroscopic observations of supernova SN 2025wny, associated with the lens candidate PS1 J0716+3821. Photometric monitoring from the Lulin and Maidanak obs…
Early Results from GLASS-JWST. XIX: A High Density of Bright Galaxies at in the Abell 2744 Region
Marco Castellano, Adriano Fontana, Tommaso Treu +38
We report the detection of a high density of redshift galaxies behind the foreground cluster Abell 2744, selected from imaging data obtained recently with NIRCam onbo…
Systematic search for lensed X-ray sources in the CLASH fields
Ang Liu, Paolo Tozzi, Piero Rosati +8
We search for unresolved X-ray emission from lensed sources in the FOV of 11 CLASH clusters with Chandra data. We consider the solid angle in the lens plane corresponding to a magn…
The projected gravitational potential of the galaxy cluster MACS~J1206 derived from galaxy kinematics
Dennis Stock, Sven Meyer, Eleonora Sarli +7
We reconstruct the radial profile of the projected gravitational potential of the galaxy cluster MACS-J1206 from 592 spectroscopic measurements of velocities of cluster members. Fo…
Unveiling the Universe with Emerging Cosmological Probes
Michele Moresco, Lorenzo Amati, Luca Amendola +22
The detection of the accelerated expansion of the Universe has been one of the major breakthroughs in modern cosmology. Several cosmological probes (CMB, SNe Ia, BAO) have been stu…
A new high-precision strong lensing model of the galaxy cluster MACS J0416.1-2403
Pietro Bergamini, Piero Rosati, Eros Vanzella +8
We present a new high-precision parametric strong lensing model of the galaxy cluster MACS J0416.1-2403, at z=0.396, which takes advantage of the MUSE Deep Lensed Field (MDLF), wit…
The Kormendy Relation of Galaxies in the Frontier Fields Clusters: Abell S1063 and MACS J1149.5+2223
Luca Tortorelli, Amata Mercurio, Maurizio Paolillo +12
We analyse the Kormendy relations (KRs) of the two Frontier Fields clusters, Abell S1063, at z = 0.348, and MACS J1149.5+2223, at z = 0.542, exploiting very deep Hubble Space Teles…
The Contribution of Halos with Different Mass Ratios to the Overall Growth of Cluster-Sized Halos
Doron Lemze, Marc Postman, Shy Genel +39
We provide a new observational test for a key prediction of the ÎCDM cosmological model: the contributions of mergers with different halo-to-main-cluster mass ratios to cluster-si…
Diverse Oxygen Abundance in Early Galaxies Unveiled by Auroral Line Analysis with JWST
Takahiro Morishita, Massimo Stiavelli, Claudio Grillo +10
We present deep JWST NIRSpec observations in the sightline of MACS J1149.5+2223, a massive cluster of galaxies at . We report the spectroscopic redshift of 28 sources at $3…
Three Gravitationally Lensed Supernovae Behind CLASH Galaxy Clusters
Brandon Patel, Curtis McCully, Saurabh W. Jha +42
We report observations of three gravitationally lensed supernovae (SNe) in the Cluster Lensing And Supernova survey with Hubble (CLASH) Multi-Cycle Treasury program. These objects,…
A highly magnified candidate for a young galaxy seen when the Universe was 500 Myrs old
Wei Zheng, Marc Postman, Adi Zitrin +33
The early Universe at redshift z\sim6-11 marks the reionization of the intergalactic medium, following the formation of the first generation of stars. However, those young galaxies…
CLASH: Complete Lensing Analysis of the Largest Cosmic Lens MACS J0717.5+3745 and Surrounding Structures
Elinor Medezinski, Keiichi Umetsu, Mario Nonino +35
The galaxy cluster MACS J0717.5+3745 (z=0.55) is the largest known cosmic lens, with complex internal structures seen in deep X-ray, Sunyaev-Zel'dovich effect and dynamical observa…
Galaxies in the central regions of simulated galaxy clusters
Antonio Ragagnin, Massimo Meneghetti, Luigi Bassini +20
In this paper, we assess the impact of numerical resolution and of the implementation of energy input from AGN feedback models on the inner structure of cluster sub-haloes in hydro…
A stellar dynamical mass measurement of an inactive black hole at redshift 2
Andrew B. Newman, Meng Gu, Sirio Belli +34
Supermassive black holes and their host galaxies grow together over time, producing correlations between the black hole mass and various galaxy properties. Determining the evolutio…
Early Results from GLASS-JWST. I: Confirmation of Lensed Lyman-Break Galaxies Behind the Abell 2744 Cluster With NIRISS
Guido Roberts-Borsani, Takahiro Morishita, Tommaso Treu +29
We present the first search for , continuum-confirmed sources with NIRISS/WFS spectroscopy over the Abell 2744 Frontier Fields cluster, as part of the GLASS-JWST ERS s…
Signatures and bias assessment of rotation in galaxy cluster members
Davide Castellani, Giovanni Ferrami, Claudio Grillo +1
We investigate the possible presence of systematic rotation in the member galaxies of a sample of 17 nearby (), rich (at least 80 identified members) Abell clusters. We also…
Galaxy halo truncation and Giant Arc Surface Brightness Reconstruction in the Cluster MACSJ1206.2-0847
Thomas Eichner, Stella Seitz, Sherry H. Suyu +32
In this work we analyze the mass distribution of MACSJ1206.2-0847, especially focusing on the halo properties of its cluster members. The cluster appears relaxed in its X-ray emiss…
The Grism Lens-Amplified Survey from Space (GLASS) X. Sub-kpc resolution gas-phase metallicity maps at cosmic noon behind the Hubble Frontier Fields cluster MACS1149.6+2223
Xin Wang, Tucker A. Jones, Tommaso Treu +17
(Abridged) We combine deep HST grism spectroscopy with a new Bayesian method to derive maps of gas-phase metallicity, nebular dust extinction, and star-formation rate for 10 star-f…
Exploring the low-mass regime of galaxy-scale strong lensing: Insights into the mass structure of cluster galaxies
Giovanni Granata, Pietro Bergamini, Claudio Grillo +8
We aim at a direct measurement of the compactness of three galaxy-scale lenses in massive clusters, testing the accuracy of the scaling laws that describe the members in strong len…
Hubble Space Telescope Combined Strong and Weak Lensing Analysis of the CLASH Sample: Mass and Magnification Models and Systematic Uncertainties
Adi Zitrin, Agnese Fabris, Julian Merten +23
We present results from a comprehensive lensing analysis in HST data, of the complete CLASH cluster sample. We identify new multiple-images previously undiscovered allowing improve…
The GLASS-JWST Early Release Science Programme: The NIRISS Spectroscopic Catalogue
Peter J. Watson, Benedetta Vulcani, Tommaso Treu +18
We present a spectroscopic redshift catalogue of sources in the Abell 2744 cluster field, derived from JWST/NIRISS observations taken as part of the GLASS-JWST Early Release Scienc…
The probability of galaxy-galaxy strong lensing events in hydrodynamical simulations of galaxy clusters
Massimo Meneghetti, Antonio Ragagnin, Stefano Borgani +27
Meneghetti et al. (2020) recently reported an excess of galaxy-galaxy strong lensing (GGSL) in galaxy clusters compared to expectations from the LCDM cosmological model. Theoretica…
Strong Lensing by Galaxy Clusters
Priyamvada Natarajan, Liliya L. Williams, Marusa Bradac +4
Galaxy clusters as gravitational lenses play a unique role in astrophysics and cosmology: they permit mapping the dark matter distribution on a range of scales; they reveal the pro…
Near-infrared characterization of ultra-diffuse galaxies in Abell 2744 by JWST/NIRISS imaging
Ryota Ikeda, Takahiro Morishita, Takafumi Tsukui +10
We present a search and characterization of ultra-diffuse galaxies (UDGs) in the Frontier Fields cluster Abell~2744 at . We use JWST/NIRISS F200W observations, acquired as…
HOLISMOKES XIII: Strong-lens candidates at all mass scales and their environments from the Hyper-Suprime Cam and deep learning
Stefan Schuldt, Raoul Cañameras, Irham T. Andika +6
We performed a systematic search for strong gravitational lenses using Hyper Suprime-Cam (HSC) data, focusing on galaxy-scale lenses combined with an environment analysis resulting…
The powerful lens galaxy cluster PLCK G287.0+32.9 ()
Maurizio D'Addona, Amata Mercurio, Piero Rosati +17
We present a new high-precision strong lensing model of PLCK G287.032.9, a massive lens galaxy cluster at , with the aim to get an accurate estimation of its effective…
Discovery and first models of the quadruply lensed quasar SDSS J1433+6007
Adriano Agnello, Claudio Grillo, Tucker Jones +3
We report the discovery of the quadruply lensed quasar J1433+6007, mined in the SDSS DR12 photometric catalogues using a novel outlier-selection technique, without prior spectrosco…
A massive, dead disk galaxy in the early Universe
Sune Toft, Johannes Zabl, Johan Richard +10
At redshift z = 2, when the Universe was just three billion years old, half of the most massive galaxies were extremely compact and had already exhausted their fuel for star format…
Galaxy cluster virial quantities from extrapolating strong lensing mass profiles
Enrico Maraboli, Claudio Grillo, Pietro Bergamini +1
We study the radial total mass profiles of nine massive galaxy clusters ( M) in the redshift range . These clusters were obse…