A5090717138- Astronomy and Astrophysical Research
- Galaxies: Formation, Evolution, Phenomena
- Stellar, planetary, and galactic studies
- Gamma-ray bursts and supernovae
- Astrophysics and Star Formation Studies
- Adaptive optics and wavefront sensing
- Calibration and Measurement Techniques
- Radio Astronomy Observations and Technology
- Astrophysics and Cosmic Phenomena
- Astrophysical Phenomena and Observations
- Astro and Planetary Science
- High-Energy Particle Collisions Research
- Cosmology and Gravitation Theories
- History and Theory of Mathematics
- Particle physics theoretical and experimental studies
- Quantum Chromodynamics and Particle Interactions
- Spacecraft and Cryogenic Technologies
- Astronomical Observations and Instrumentation
Ludwig-Maximilians-Universität München
2023-2024
University of Ljubljana
2023-2024
ABSTRACT Early JWST observations that targeted so-called double-break sources (attributed to Lyman and Balmer breaks at z > 7), reported a previously unknown population of very massive, evolved high-redshift galaxies. This surprising discovery led flurry attempts explain these objects’ unexpected existence including invoking alternatives the standard Λ cold dark matter (ΛCDM) cosmological paradigm. To test early results, we adopted same candidate galaxy selection criteria search for...
Abstract We present a new sample of 158 galaxies at redshift z > 7.5 selected from deep James Webb Space Telescope (JWST) NIRCam imaging five widely separated sight lines in the CANUCS survey. Two-thirds pointings and 80% are covered by 12–14 filters, including seven to nine medium bands, providing accurate photometric redshifts robustness against low-redshift interlopers. A 28 with spectroscopic shows low systematic offset scatter difference between redshifts. derive galaxy UV luminosity...
Abstract We report the discovery of a low-mass z = 5.200 ± 0.002 galaxy that is in process ceasing its star formation. The galaxy, MACS0417-z5BBG, multiply imaged with magnification factors ∼40 by cluster MACS J0417.5-1154, observed as part CAnadian NIRISS Unbiased Cluster Survey (CANUCS). Using observations MACS0417-z5BBG JWST/NIRSpec Prism spectrum and NIRCam imaging, we investigate mechanism responsible for cessation formation speculate about possibilities future. spectrophotometric...
Abstract We present measurements of stellar populations properties a z = 9.1 gravitationally lensed galaxy MACS1149-JD1 using deep James Webb Space Telescope NIRISS slitless spectroscopy as well and NIRCam imaging from the CAnadian Unbiased Cluster Survey (CANUCS). The is split into four components. Three magnified ( μ ∼ 11) star-forming components are unresolved, giving intrinsic sizes <25 pc. In addition, underlying extended component contains bulk mass, formed majority its stars ∼50...
We present JWST/Near Infrared Spectrograph (NIRSpec) integral field spectroscopy (IFS) of a lensed Population III candidate stellar complex (dubbed Lensed And Pristine 1, LAP1), with lensing-corrected mass ≲10 4 M ⊙ and an absolute luminosity UV > −11.2 ( m 35.6), confirmed at redshift 6.639 ± 0.004. The system is strongly amplified μ ≳ 100) by straddling critical line the Hubble Frontier Field galaxy cluster MACS J0416. Although continuum currently not detected in Camera (NIRCam) Near...
Context. The environment inside and on the outskirts of galaxy clusters has a profound impact star formation rate active galactic nucleus (AGN) activity in cluster galaxies. While overall AGN suppression inner regions been thoroughly studied past, recent X-ray studies also indicate that conditions may promote activity. Aims. We investigate how properties host galaxies levels clusters. aim to identify significant trends different populations suggest possible explanations. Methods. with...
The most distant galaxies detected by JWST are assembling in a Universe that is less than 5\% of its present age. At these times, the progenitors like Milky Way expected to be about 10,000 times massive they now, with masses quite comparable globular clusters seen local Universe. Composed today primarily old stars and correlating properties their parent dark matter halos, first thought have formed during earliest stages galaxy assembly. In this article we explore connection between star...
ABSTRACT The epoch of reionization (EoR) progressed through the emission ionizing photons from galaxies to their local intergalactic medium. In this work, we characterize dwarf star-forming as candidates for source that drove EoR. We investigate properties and star formation histories at last stages EoR $4.8\lt z \lt 7$ using observations CAnadian NIRISS Unbiased Cluster Survey (CANUCS). magnification due gravitational lensing allows us probe large dynamic ranges in stellar mass ($2\times...
The most distant galaxies detected were seen when the Universe was a scant 5% of its current age. At these times, progenitors such as Milky Way about 10,000 times less massive. Using James Webb Space Telescope (JWST) combined with magnification from gravitational lensing, low-mass can not only be but also studied in detail. Here we present JWST observations strongly lensed galaxy at z
We report the discovery of a $z\sim7$ group galaxies that contains two Little Red Dots (LRDs) just 3.3 kpc apart, along with three satellite galaxies, as part Canadian NIRISS Unbiased Cluster Survey (CANUCS). These LRDs are massive ($M_\star\sim10^{10}\,M_\odot$) and dusty (A(V) $>1$ mag) whereas satellites lower-mass objects ($M_\star\sim10^{8-9}\,M_\odot$) subject to low dust attenuations. The spectral energy distributions (SEDs) this LRD pair show strong evidence for Balmer Break,...
We present {\it JWST} observations of a gravitationally-lensed, extremely metal-poor galaxy at redshift $z=8.203\pm 0.001$ from the CANUCS survey. Based on low oxygen to Balmer line ratios we infer gas-phase metallicity $12+{\rm log(O/H)}=6.85$ (1.4\% solar), making CANUCS-A370-z8-LAE most known $z>7$. With high H$\beta$ equivalent width $225\pm50$\,\AA\ and half-light radius only $r_{\rm hl} = 38 ^{+3}_{-19} $\,pc, has star-formation-rate density $50 -...
Strong gravitational lensing in galaxy clusters has become an essential tool astrophysics, as it allows one to directly probe the dark matter distribution and study magnified background sources. The precision reliability of strong models rely heavily on number quality multiple images sources with spectroscopic redshifts. We present updated model cluster MACS J0416.1-2403 largest sample redshifts a field date. Furthermore, we aim demonstrate effectiveness JWST, particularly its NIRISS camera,...
We present a methodology for modeling and removing light from cluster galaxies intracluster (ICL) $James\ Webb\ Space\ Telescope$ ($JWST$) images of gravitational lensing clusters. apply our method to Webb's First Deep Field the SMACS 0723 Early Release Observations use ICL subtracted select sample globular clusters (GCs) dwarf within cluster. compare spatial distributions these two samples with models galaxy light, finding significant similarity. Specifically we find that GCs trace diffuse...
Abstract We present an updated mass and magnification model of galaxy cluster A370 using new NIRCam, NIRISS, NIRSpec data from the Canadian NIRISS Unbiased Cluster Survey (CANUCS). Using Lenstool a combination archival Hubble Space Telescope (HST) MUSE with JWST as constraints, we derive improved gravitational lensing extract magnifications background galaxies uncertainties. our best fit model, perform search for multiply imaged systems via predicted positions. report no identifiable...
We report the discovery of a low-mass $z=5.200\pm 0.002$ galaxy that is in process ceasing its star formation. The galaxy, MACS0417-z5PSB, multiply imaged with magnification factors $\sim40$ by cluster MACS J0417.5-1154, observed as part CAnadian NIRISS Unbiased Cluster Survey (CANUCS). Using observations MACS0417-z5PSB JWST/NIRSpec Prism spectrum and NIRCam imaging, we investigate mechanism responsible for cessation formation speculate about possibilities future. spectrophotometric fitting,...
We present a new sample of 158 galaxies at redshift $z>7.5$ selected from deep \jwst\ NIRCam imaging five widely-separated sightlines in the CANUCS survey. Two-thirds pointings and 80\% are covered by 12 to 14 filters, including seven nine medium bands, providing accurate photometric redshifts robustness against low interlopers. A 28 with spectroscopic shows systematic offset scatter difference between redshifts. derive galaxy UV luminosity function 8 12, finding slightly higher...
Abstract The most distant galaxies detected by JWST are assembling in a Universe that is less than 5% of its present age. At these times, the progenitors like Milky Way expected to be about 10,000 times massive they now, with masses quite comparable globular clusters seen local Universe. Composed today primarily old stars and correlating properties their parent dark matter halos, first thought have formed during earliest stages galaxy assembly. In this article we explore connection between...
We report the serendipitous discovery of a faint (M UV > −12.2), low-metallicity (Z ∼ 0.02 Z⊙) ionizing source, dubbed T2c, with spectroscopic redshift z = 6.146. T2c is part larger structure amplified by Hubble Frontier Field galaxy cluster MACSJ0416 and was observed James Webb Space Telescope (JWST) NIRSpec integral field unit. Stacking short-wavelength NIRCam data reveals no stellar continuum detection down to magnitude limit m ≃ 31.0 (3 σ ). However, prominent H β , [O III ] λ 4959,...
Abstract We present a methodology for modeling and removing light from cluster galaxies intracluster (ICL) James Webb Space Telescope images of gravitational lensing clusters. apply our method to Webb’s First Deep Field the SMACS 0723 Early Release Observations use ICL-subtracted select sample globular clusters (GCs) dwarf within cluster. compare spatial distributions these two samples with models galaxy ICL light, finding significant similarities. In particular, we find that GCs trace...
We present JWST/NIRSpec integral field spectroscopy (IFS) of a lensed Population III candidate stellar complex (dubbed Lensed And Pristine 1, LAP1), with lensing-corrected mass ~<10^4 Msun, absolute luminosity M_UV > -11.2 (m_UV 35.6), confirmed at redshift 6.639 +/- 0.004. The system is strongly amplified (μ>~ 100) by straddling critical line the Hubble Frontier Field galaxy cluster MACS J0416. Despite continuum currently not detected in and JWST/NIRCam NIRISS imaging, arclet-like...
We present measurements of stellar populations properties a z = 9.1 gravitationally lensed galaxy MACS1149-JD1 using deep JWST NIRISS slitless spectroscopy as well and NIRCam imaging from the CAnadian Unbiased Cluster Survey (CANUCS). The is split into four components. Three magnified (${\mu}$ ~ 17) star-forming components are unresolved, giving intrinsic sizes < 50pc. In addition, underlying extended component contains bulk mass, formed majority its stars 50Myr earlier than other three not...
We report an updated mass and magnification model of galaxy cluster Abell 370 using new NIRCam NIRISS data from the CAnadian Unbiased Cluster Survey (CANUCS). Using Lenstool a combination archival HST MUSE with JWST as constraints, we derive improved gravitational lensing extract magnifications background galaxies uncertainties. our best fit model, perform search for multiply imaged systems via predicted positions. no identifiable redshifts, likely due to already very deep Spitzer data, but...
Strong gravitational lensing in galaxy clusters has become an essential tool astrophysics, allowing us to directly probe the dark matter distribution and study magnified background sources. The precision reliability of strong models rely heavily on number quality multiple images sources with spectroscopic redshifts. We present updated model cluster MACS J0416.1-2403 largest sample redshifts a field date. Furthermore, we aim demonstrate effectiveness JWST particularly its NIRISS camera, for...
The epoch of reionisation progressed through the emission ionising photons from galaxies to their local intergalactic medium. In this work, we characterise dwarf star-forming as candidates for source that drove EoR. We investigate properties and star formation histories at last stages EoR $4.8<\rm{z}<7$ using observations CAnadian NIRISS Unbiased Cluster Survey (CANUCS). magnification due gravitational lensing allows us probe large dynamic ranges in stellar mass ($2\times...
The James Webb Space Telescope (JWST) has recently discovered a new population of objects at high redshift referred to as `Little Red Dots' (LRDs). Their nature currently remains elusive, despite their surprisingly inferred number densities. This emerging red point-like sources is reshaping our view the early Universe and may shed light on formation high-redshift supermassive black holes. Here we present spectroscopically confirmed LRD CANUCS-LRD-z8.6 $z_{\rm spec}=8.6319\pm 0.0005$ hosting...