A5115598866- Astronomy and Astrophysical Research
- Galaxies: Formation, Evolution, Phenomena
- Stellar, planetary, and galactic studies
- Adaptive optics and wavefront sensing
- Gamma-ray bursts and supernovae
- Astronomical Observations and Instrumentation
- Astrophysics and Star Formation Studies
- Dark Matter and Cosmic Phenomena
- Astrophysical Phenomena and Observations
- History and Developments in Astronomy
- Particle Detector Development and Performance
- Geophysics and Gravity Measurements
- Oceanographic and Atmospheric Processes
- Tropical and Extratropical Cyclones Research
- Cosmology and Gravitation Theories
- CCD and CMOS Imaging Sensors
- Bayesian Methods and Mixture Models
- Radio Astronomy Observations and Technology
- Infrared Target Detection Methodologies
- Geophysics and Sensor Technology
- Probability and Risk Models
- Calibration and Measurement Techniques
- Astro and Planetary Science
- Satellite Image Processing and Photogrammetry
- Methane Hydrates and Related Phenomena
Donostia International Physics Center
2019-2025
Ikerbasque
2018-2025
University of the Basque Country
2018-2025
Tel Aviv University
2015
Hebrew University of Jerusalem
2002
University of California, Berkeley
1998-1999
Royal Observatory
1992
(Abridged) Several aspects of the evolution star-forming galaxies are studied using measures 2-dimensional surface brightness profile a sample 341 faint objects selected from CFRS and LDSS redshift surveys that have been observed with Hubble Space Telescope. The size function disk scale lengths in disk-dominated is found to stay roughly constant z=1. This result, which strengthened by inclusion local de Jong et al (1996) function, suggests typical disks can not grown substantially cosmic...
Abstract We present a multiwavelength analysis using the Submillimeter Array (SMA), James Clerk Maxwell Telescope, NOEMA, JWST, Hubble Space Telescope (HST), and Spitzer of two dusty strongly star-forming galaxies, 850.1 850.2, seen through massive cluster lens A 1489. These SMA-located sources both lie at z = 4.26 have bright dust continuum emission, but 850.2 is UV-detected Lyman-break galaxy, while undetected ≲ 2 μ m, even with deep JWST/NIRCam observations. investigate their stellar,...
Abstract Dark matter subhalos with extended profiles and density cores, globular star clusters of mass 10 6 –10 8 M ⊙ that live near the critical curves in galaxy cluster lenses can potentially be detected through their lensing magnification stars background galaxies. In this work, we study effect such have on lensed images, compare to case more well-studied microlensing by black holes curves. We find gradient distribution are important determining image properties. Both lead an asymmetry...
Individual highly magnified stars have been recently discovered at lookback times of more than half the age Universe, in lensed galaxies that straddle critical curves massive galaxy clusters. Having confirmed their detectability, it is now important to carry out systematic searches for them order establish frequency, and turn learn about statistical properties high-redshift granularity matter foreground deflector. Here we report discovery a star redshift $z = 0.94$ strongly arc behind Hubble...
We have selected a sample of eleven massive clusters galaxies observed by the Hubble Space Telescope in order to study impact dynamical state on IntraCluster Light (ICL) fraction, ratio total integrated ICL galaxy member light. With exception Bullet cluster, is drawn from Cluster Lensing and Supernova Survey Frontier Fields program, containing five relaxed six merging clusters. The fraction calculated three optical filters using CHEFs Estimator, robust accurate algorithm free priori...
Abstract We present a full analysis of galaxy major merger pair fractions, rates, and mass accretion thus uncovering the role mergers in formation at earliest previously unexplored epoch 4.5 < z 11.5. target galaxies with masses log10(M*/M⊙) = 8.0 − 10.0, utilizing data from eight JWST Cycle-1 fields (CEERS, JADES GOODS-S, NEP-TDF, NGDEEP, GLASS, El-Gordo, SMACS-0723, MACS-0416), covering an unmasked area 189.36 arcmin2. develop new probabilistic pair-counting methodology that...
We derive the spatial and wavelength behavior of dust attenuation in multiple-armed spiral galaxy VV191b using backlighting by superimposed elliptical system VV191a a pair with an exceptionally favorable geometry for this measurement. Imaging JWST HST spans range 0.3-4.5 microns high angular resolution, tracing detail from 0.6 to 1.5 microns. Distinct lanes continue well beyond bright arms, trace complex web, very sharp radial cutoff near 1.7 Petrosian radii. present profiles coverage...
We present a novel measurement of the pairwise peculiar velocity distribution function galaxies on scales r<3200 km s-1 in Las Campanas Redshift Survey. The is well described by scale-independent exponential with width τ, where σ12 = √2τ=363 s-1. signal very stable. Results from northern and southern sets slices agree within ±13 s-1, fluctuations among six individual survey vary as ±44 was determined using Fourier-space deconvolution redshift-space distortions correlation function. This...
We report on our first set of spectroscopic Hubble Space Telescope observations the candidate galaxy, which is strongly lensed by MACSJ 0647.7+7015 galaxy cluster. The three images are faint and we show that these early slitless grism sufficient depth to investigate whether this high-redshift candidate, identified its strong photometric break at , could possibly be an emission line a much lower redshift. While such interloper would imply existence rather peculiar object, here lines clearly...
We present a full analysis of galaxy major merger pair fractions, rates, and mass accretion thus uncovering the role mergers in formation at earliest previously unexplored epoch $4.5<z<11.5$. target galaxies with masses $\log_{10}(\mathrm{M}_*/\mathrm{M}_\odot) = 8.0 - 10.0$, utilizing data from eight JWST Cycle-1 fields (CEERS, JADES GOODS-S, NEP-TDF, NGDEEP, GLASS, El-Gordo, SMACS-0723, MACS-0416), covering an unmasked area 189.36 $\mathrm{arcmin}^2$. develop new probabilistic...
Once only accessible in nearby galaxies, we can now study individual stars across much of the observable universe aided by galaxy-cluster gravitational lenses. When a star, compact object, or multiple such objects foreground lens become aligned, they magnify background and timescale magnification peak limit its size to tens AU. The number frequency microlensing events therefore opens window into population objects, as well high-redshift stars. To assemble first statistical sample order...
We present a multi-wavelength analysis using SMA, JCMT, NOEMA, JWST, HST, and SST of two dusty strongly star-forming galaxies, 850.1 850.2, seen through the massive cluster lens A1489. These SMA-located sources both lie at z=4.26 have bright dust continuum emission, but 850.2 is UV-detected Lyman-break galaxy, while undetected <2um, even with deep JWST/NIRCam observations. investigate their stellar, ISM, dynamical properties, including pixel-level SED to derive sub-kpc-resolution...
We examine the clustering properties of low-redshift Lyα and heavy-element QSO absorption line systems seen in spectra 13 QSOs at Galactic poles. This is densest sample ~1° separated observed spectroscopically with Hubble Space Telescope to date. At median redshift (z ≈ 0.7), lines sight are on transverse scales from about 15 200 h-1 Mpc (q0=0.5, H=100 h km s-1 Mpc-1), allowing three-dimensional absorbers be examined those scales. The poles also regions where relatively deep wide-field...
We study the nature of transient events detected in "Dragon Arc", a star-forming galaxy at redshift $0.7251$ that is gravitationally lensed by cluster Abell 370. In particular, we focus on subset ten transients are identified as unresolved young star clusters deep broadband, F200LP, taken part "Flashlights" Hubble Space Telescope program, showing flux variations $\sim 10-20\%$ over period about year. Here develop several methods to address whether stellar microlensing alone capable...
We compare the abundant prolate shaped galaxies reported beyond z$>$3 in deep JWST surveys, with predicted {\it stellar} appearance of young detailed hydro-simulations three main dark matter contenders: Cold (CDM), Wave/Fuzzy ($\psi$DM) and Warm Dark Matter (WDM). find observed galaxy images closely resemble elongated stellar for both $\psi$DM WDM, during first $\simeq$ 500Myr while material steadily accretes from long, smooth filaments. The mater halos WDM also have pronounced, elongation...
Galaxy mergers are a key driver of galaxy formation and evolution, including the triggering AGN star to still unknown degree. We thus investigate impact on activity using sample 3,330 galaxies at $z = [4.5, 8.5]$ from eight JWST fields (CEERS, JADES GOODS-S, NEP-TDF, NGDEEP, GLASS, El-Gordo, SMACS-0723, MACS-0416), collectively covering an unmasked area 189 arcmin$^2$. focuses rate (SFR) enhancement, fraction, excess in major merger ($\mu > 1/4$) close-pair samples, defined by $\Delta z <...
We present a structural analysis of 521 galaxy candidates at 6.5 < z 12.5, with $SNR > 10\sigma$ in the F444W filter, taken from EPOCHS v1 sample, consisting uniformly reduced deep JWST NIRCam data, covering CEERS, JADES GOOD-S, NGDEEP, SMACS0723, GLASS and PEARLS surveys. use standard software to fit single S\'ersic models each rest-frame optical extract their parametric parameters (S\'ersic index, half-light radius axis-ratio), \texttt{Morfometryka} measure non-parametric concentration...
<title>Abstract</title> Low mass galaxies in the Local Group are dominated by dark matter and comprise well studied “dwarf Spheroidal" (dSph) class, with typical masses of 10<sup>9−10</sup><italic>M</italic><sub>⊙</sub> also equally numerous “ultra faint dwarfs" (UFD), discovered recently, that distinctly smaller denser only 10<sup>7−8</sup><italic>M</italic><sub>⊙</sub>. This bimodality amongst low contrasts scale free continuity expected for formed under gravity, as standard Cold Dark...
Dark matter subhalos with extended profiles and density cores, globular stars clusters of mass $10^6-10^8 M_\odot$, that live near the critical curves in galaxy cluster lenses can potentially be detected through their lensing magnification background galaxies. In this work we study effect such have on lensed images, compare to case more well studied microlensing by black holes curves. We find gradient distribution are important determining image properties. Both lead an asymmetry between...