A5015179666- Galaxies: Formation, Evolution, Phenomena
- Astronomy and Astrophysical Research
- Astrophysics and Star Formation Studies
- Stellar, planetary, and galactic studies
- Gamma-ray bursts and supernovae
- Astrophysical Phenomena and Observations
- Adaptive optics and wavefront sensing
- Astrophysics and Cosmic Phenomena
- Astronomical Observations and Instrumentation
- CCD and CMOS Imaging Sensors
- Radio Astronomy Observations and Technology
- Cosmology and Gravitation Theories
- Scientific Research and Discoveries
- Spectroscopy and Laser Applications
- Photocathodes and Microchannel Plates
- History and Developments in Astronomy
- Geophysics and Gravity Measurements
- Calibration and Measurement Techniques
- Atmospheric Ozone and Climate
- Atomic and Subatomic Physics Research
- Particle Detector Development and Performance
- Advanced Fluorescence Microscopy Techniques
- Nuclear Physics and Applications
- Atmospheric and Environmental Gas Dynamics
- Dark Matter and Cosmic Phenomena
ETH Zurich
2019-2025
Wolfgang Pauli Institute
2025
Institute of Science and Technology Austria
2023-2024
Leiden University
2013-2019
Faint Lyα emitters become increasingly rarer toward the reionization epoch (z ∼ 6–7). However, observations from a very large (∼5 deg2) narrow-band survey at z = 6.6 show that this is not case for most luminous emitters, capable of ionizing their own local bubbles. Here we present follow-up two candidates in COSMOS field: "MASOSA" and "CR7." We used X-SHOOTER, SINFONI, FORS2 on Very Large Telescope, DEIMOS Keck, to confirm both beyond any doubt. find redshifts 6.541 6.604 "CR7,"...
Abstract The first few 100 Myr at z > 10 mark the last major uncharted epoch in history of universe, where only a single galaxy (GN-z11 ≈ 11) is currently spectroscopically confirmed. Here we present search for luminous galaxies with JWST/NIRCam photometry spanning ≈1–5 μ m and covering 49 arcmin 2 from public JWST Early Release Science programs (CEERS GLASS). Our most secure candidates are two M UV −21 systems: GLASS-z12 GLASS-z10. These display abrupt ≳1.8 mag breaks their spectral...
Abstract Characterizing the prevalence and properties of faint active galactic nuclei (AGNs) in early Universe is key for understanding formation supermassive black holes (SMBHs) determining their role cosmic reionization. We perform a spectroscopic search broad H α emitters at z ≈ 4–6 using deep JWST/NIRCam imaging wide field slitless spectroscopy from EIGER FRESCO surveys. identify 20 lines = 4.2–5.5 that have components with line widths ∼1200–3700 km s −1 , contributing ∼30%–90% total...
Abstract The James Webb Space Telescope is revealing a new population of dust-reddened broad-line active galactic nuclei (AGN) at redshifts z ≳ 5. Here we present deep NIRSpec/Prism spectroscopy from the Cycle 1 Treasury program Ultradeep NIRSpec and NIRCam ObserVations before Epoch Reionization (UNCOVER) 15 AGN candidates selected to be compact, with red continua in rest-frame optical but blue slopes UV. From photometry alone, they could have been dominated by dusty star formation or an...
ABSTRACT We present the first constraints on prevalence of z > 10 galaxies in Hubble Ultra Deep Field (HUDF) leveraging new NIRCam observations from JEMS (JWST Extragalactic Medium-band Survey). These probe redward 1.6 μm, beyond wavelength limit HST, allowing us to search for 10. indicate that highest redshift candidate identified HUDF09 data with UDFj-39546284, has a 11.5, as had been suggested analyses HUDF12/XDF data. This now confirmed JWST NIRSpec. source is thus most distant...
We present emission-line measurements and physical interpretations for a sample of 117 [OIII] emitting galaxies at $z=5.33-6.93$, using the first deep JWST/NIRCam wide field slitless spectroscopic observations. Our 9.7-hour integration is centered upon $z=6.3$ quasar J0100+2802 -- six fields targeted by EIGER survey covers $\lambda=3-4$ microns. detect 133 doublets, but merge pairs within $\approx$10 kpc 600 km s$^{-1}$, motivated their small scale clustering excess. H$\beta$ in 68 H$\gamma$...
ABSTRACT We present the JWST cycle 1 53.8 h medium program FRESCO, short for ‘First Reionization Epoch Spectroscopically Complete Observations’. FRESCO covers 62 arcmin2 in each of two GOODS/CANDELS fields a total area 124 exploiting JWST’s powerful new grism spectroscopic capabilities at near-infrared wavelengths. By obtaining ∼2 deep NIRCam/grism observations with F444W filter, yields unprecedented spectra R ∼ 1600 covering 3.8–5.0 µm most galaxies NIRCam field view. This setup enables...
Abstract We present a first sample of 117 [O iii ] λλ 4960, 5008–selected star-forming galaxies at 5.33 < z 6.93 detected in JWST/NIRCam 3.5 μ m slitless spectroscopy <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" overflow="scroll"> <mml:mn>6</mml:mn> <mml:mrow> <mml:mo>.′</mml:mo> </mml:mrow> <mml:mn>5</mml:mn> <mml:mspace width="0.25em"/> <mml:mo>×</mml:mo> <mml:mn>3</mml:mn> <mml:mn>4</mml:mn> </mml:math> field centered on the hyperluminous quasar SDSS J0100+2802, obtained as...
Abstract We report JWST/NIRCam measurements of quasar host galaxy emissions and supermassive black hole (SMBH) masses for six quasars at 5.9 < z 7.1 in the Emission-line galaxies Intergalactic Gas Epoch Reionization (EIGER) project. obtain deep NIRCam imaging F115W, F200W, F356W bands, as well grism spectroscopy quasars. use bright unsaturated stars to construct models point-spread functions (PSFs) estimate errors these PSFs. then measure or constrain fluxes morphology by fitting images a...
Primordial neutral atomic gas, mostly composed of hydrogen, is the raw material for star formation in galaxies. However, there are few direct constraints on amount hydrogen (H i ) galaxies at early cosmic times. We analyzed James Webb Space Telescope (JWST) near-infrared spectroscopy distant galaxies, redshifts ≳8. From a sample 12 we identified three that show strong damped Lyman-α absorption due to H their local surroundings. The located spectroscopic 8.8, 10.2, and 11.4, corresponding 400...
Abstract The identification of red, apparently massive galaxies at z > 7 in early James Webb Space Telescope (JWST) photometry suggests a strongly accelerated time line compared to standard models galaxy growth. A major uncertainty the interpretation is whether red colors are caused by evolved stellar populations, dust, or other effects such as emission lines active galactic nuclei (AGNs). Here we show that three candidates = 6.7–8.4 have prominent Balmer breaks JWST/NIRSpec spectroscopy...
Abstract Within the established framework of structure formation, galaxies start as systems low stellar mass and gradually grow into far more massive galaxies. The existence in first billion years Universe, suggested by recent observations, seems to challenge this model, such would require highly efficient conversion baryons stars. An even greater epoch is that have already ceased forming However, robust detections early quiescent been challenging due coarse wavelength sampling photometric...
Abstract We report the detection of a 13σ Hα emission line from HDF850.1 at z = 5.188 ± 0.001 using FRESCO NIRCam F444W grism observations. Detection in is noteworthy, given its high far-IR luminosity, substantial dust obscuration, and historical challenges deriving redshift. shows clear imaging data, distributed between northern southern component, mirroring that seen [CII] Plateau de Bure Interferometer. Modeling SED each component separately, we find has higher mass, star formation rate...
Using wide field narrow-band surveys, we provide a new measurement of the $z=6.6$ Lyman-$\alpha$ Emitter (LAE) luminosity function (LF), which constraints bright end for first time. We use combination archival NB921 data in UDS and measurements SA22 COSMOS/UltraVISTA, all observed with Subaru telescope, total area $\sim 5$ deg$^2$. exclude lower redshift interlopers by using broad-band optical near-infrared photometry also three supernovae split over multiple epochs. Combining COSMOS samples...
We investigate the morphology of [CII] emission in a sample "normal" star-forming galaxies at $5<z<7.2$ relation to their UV (rest-frame) counterpart. use new ALMA observations $z\sim6-7$ as well careful re-analysis archival data. In total 29 were analysed, 21 which are detected [CII]. For several latter breaks into multiple components. Only fraction these components, if any, is associated with primary systems, while bulk either fainter or not any counterpart current limits. By taking...
We use the hydrodynamical EAGLE simulation to study magnitude and origin of scatter in stellar mass - halo relation for central galaxies. separate cause effect by correlating masses baryonic with properties a matched dark matter only (DMO) simulation. The increases redshift decreases mass. At $z = 0.1$ it declines from 0.25 dex at $M_{200, \rm DMO} \approx 10^{11}$ M$_{\odot}$ 0.12 10^{13}$ M$_{\odot}$, but trend is weak above $10^{12}$ M$_{\odot}$. For < 10^{12.5}$ up 0.04 due...
We present and explore deep narrow- medium-band data obtained with the Subaru Isaac Newton Telescopes in ∼2 deg2 COSMOS field. use these as an extremely wide, low-resolution (R ∼ 20–80) Integral Field Unit survey to slice through field obtain a large sample of ∼4000 Ly α emitters (LAEs) from z 2 6 16 redshift slices (SC4K). new luminosity functions (LFs) covering comoving volume ∼108 Mpc3. SC4K extensively complements ultradeep surveys, jointly over 4 dex revealing global (2.5 < 6) synergy...
We study the production rate of ionizing photons a sample 588 H$\alpha$ emitters (HAEs) and 160 Lyman-$\alpha$ (LAEs) at $z=2.2$ in COSMOS field order to assess implied emissivity from galaxies, based on their UV luminosity. By exploring rest-frame Lyman Continuum (LyC) with GALEX/$NUV$ data, we find f$_{\rm esc} < 2.8\, (6.4)$% through median (mean) stacking. combining luminosity density IGM measurements absorption studies, globally averaged $\langle$f$_{\rm esc}\rangle$...
Observations have revealed that the star formation rate (SFR) and stellar mass (Mstar) of star-forming galaxies follow a tight relation known as galaxy main sequence. However, what physical information is encoded in this under debate. Here, we use EAGLE cosmological hydrodynamical simulation to study dependence, evolution, origin scatter SFR–Mstar relation. At |$z$| = 0, find decreases slightly with from 0.35 dex at Mstar ≈ 109 M⊙ 0.30 ≳ 1010.5 M⊙. The 0 5 by 0.05 1010 0.15 for lower masses....
The ionizing photon escape fraction (LyC $f_{\rm{esc}}$) of star-forming galaxies is the single greatest unknown in reionization budget. Stochastic sightline effects prohibit direct separation LyC leakers from non-leakers at significant redshift. Here we circumvent this uncertainty by inferring $f_{\rm{esc}}$ with resolved (R>4000) LyA profiles X-SHOOTER survey z=2 (XLS-z2). We select ($f_{\rm{esc}}>20$%) and ($f_{\rm{esc}}<5$%) a representative sample $>0.2 L^{*}$ emitters (LAEs). With...
We present new results from the widest narrow band survey search for Lyman-alpha (Lya) emitters at z=5.7, just after reionization. a total of 7 deg$^2$ spread over COSMOS, UDS and SA22 fields. find 11,000 line emitters, out which 514 are robust Lya candidates z=5.7 within volume 6.3x10$^6$ Mpc$^3$. Our span wide range in luminosities, faint to bright (L$_{\rm Ly\alpha}\sim10^{42.5-44}$ erg s$^{-1}$) rest-frame equivalent widths (EW$_0$~25-1000 \AA) single, homogeneous data-set. By combining...
We present the CAlibrating LYMan-$α$ with H$α$ (CALYMHA) pilot survey and new results on Lyman-$α$ (Lya) selected galaxies at z~2. use a custom-built Lya narrow-band filter Isaac Newton Telescope, designed to provide matched volume coverage z=2.23 Ha HiZELS survey. Here we first for COSMOS UDS fields. Our currently reaches 3$σ$ line flux limit of ~4x10$^{-17}$ erg/s/cm$^{2}$, luminosity ~10$^{42.3}$ erg/s. find 188 emitters over 7.3x10$^5$ Mpc$^{3}$, but also significant numbers other...
We present dynamical measurements from the KMOS (K-band Multi-Object Spectrograph) Deep Survey (KDS), which is comprised of 77 typical star-forming galaxies at z $\simeq$ 3.5 in mass range 9.0 < log(M$_{\star}$/M$_{\odot}$) 10.5. These constrain internal dynamics, intrinsic velocity dispersions (σ$_{int}$) and rotation velocities (V$_{C}$) high redshift Universe. The mean dispersion our sample σ$_{int}$ = $70.8^{+3.3}_{-3.1}$ km s$^{-1}$, revealing that increasing average with redshift,...
We investigate correlations between different physical properties of star-forming galaxies in the 'Evolution and Assembly GaLaxies their Environments' (EAGLE) cosmological hydrodynamical simulation suite over redshift range 0 ≤ z 4.5. A principal component analysis reveals that neutral gas fraction (fgas,neutral), stellar mass (Mstellar) star formation rate (SFR) account for most variance seen population, with tracing a two-dimensional, nearly flat, surface three-dimensional space fgas,...