Marcin Sawicki
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View article: Extreme properties of a compact and massive accreting black hole host in the first 500 Myr
Extreme properties of a compact and massive accreting black hole host in the first 500 Myr Open
View article: A Deep Dive down the Broad-line Region: Permitted O <scp>I</scp> , Ca <scp>II,</scp> and Fe <scp>II</scp> Emission in an Active Galactic Nucleus Little Red Dot at <i>z</i> = 5.3
A Deep Dive down the Broad-line Region: Permitted O <span>I</span> , Ca <span>II,</span> and Fe <span>II</span> Emission in an Active Galactic Nucleus Little Red Dot at <i>z</i> = 5.3 Open
We present a spectroscopic analysis of a broad-line active galactic nucleus (AGN) selected as a little red dot (LRD) at z = 5.3 behind the Bullet cluster (Bz5.3) based on JWST/NIRCam and NIRSpec data. The detection of strong Fe ii , O i , …
View article: JWST Photometry of Globular Cluster Populations in MACS0417.5−1154
JWST Photometry of Globular Cluster Populations in MACS0417.5−1154 Open
Deep JWST imaging of the massive galaxy cluster MACS0417.5−1154, at redshift z = 0.443, reveals a huge population of globular clusters (GCs) and ultracompact dwarfs (UCDs) primarily distributed around its single central giant brightest clu…
View article: Evolution of the Physical Properties of the Most Massive Galaxies in Clusters and Their Protohalos
Evolution of the Physical Properties of the Most Massive Galaxies in Clusters and Their Protohalos Open
We investigated the evolution of the physical properties of the brightest galaxies in clusters and their protohalos from z = 4 to z = 0. Galaxy clusters and groups are identified using a halo-based group finder applied to the COSMOS2020 ga…
View article: The rise and fall of Little Red Dots could be driven by the environment
The rise and fall of Little Red Dots could be driven by the environment Open
The Little Red Dot (LRD) paradigm comprises three main unknowns that are intrinsically connected: (1) What is the nature of these sources? (2) How do they form? (3) How do they evolve? Larger spectroscopic samples and high-resolution data …
View article: Metal-poor Star-forming Clumps in Cosmic Noon Galaxies: Evidence for Gas Inflow and Chemical Dilution Using JWST NIRISS
Metal-poor Star-forming Clumps in Cosmic Noon Galaxies: Evidence for Gas Inflow and Chemical Dilution Using JWST NIRISS Open
The formation and evolution of galaxies are intricately linked to the baryon cycle, which fuels star formation while shaping chemical abundances within galaxies. Investigating the relationship between star formation and metallicity for lar…
View article: Probing the Star Formation Main Sequence down to 10$^{7} M_\odot$ at $1 < z < 9$
Probing the Star Formation Main Sequence down to 10$^{7} M_\odot$ at $1 < z < 9$ Open
The Main Sequence of Star-Forming Galaxies (SFGMS or MS) is a fundamental scaling relation that provides a global framework for studying galaxy formation and evolution, as well as insight into the complex star formation histories (SFHs) of…
View article: Evolution of the Physical Properties of the Most Massive Galaxies in Clusters and their Protohalos
Evolution of the Physical Properties of the Most Massive Galaxies in Clusters and their Protohalos Open
We investigated the evolution of the physical properties of the brightest galaxies in clusters and their protohalos from $z = 4$ to $z = 0$. Galaxy clusters and groups are identified using a halo-based group finder applied to the COSMOS202…
View article: No Luminous Little Red Dots: A Sharp Cutoff in Their Luminosity Function
No Luminous Little Red Dots: A Sharp Cutoff in Their Luminosity Function Open
One of the most surprising results of early James Webb Space Telescope (JWST) observations is the discovery of an abundance of red, compact, broad-line objects dubbed "little red dots" (LRDs) at $z>4$. Their spatial density ($\sim10^{-4}$-…
View article: CANUCS/Technicolor: JWST Medium-band Photometry Finds Half of the Star Formation at <i>z</i> > 7.5 Is Obscured
CANUCS/Technicolor: JWST Medium-band Photometry Finds Half of the Star Formation at <i>z</i> > 7.5 Is Obscured Open
We present a sample of 110 high-redshift ( z > 7.5) galaxies from the CANUCS and Technicolor surveys, showcasing photometry in every wide- and medium-band NIRCam filter in addition to ancillary Hubble Space Telescope data sampling 0.4–5 μ …
View article: The Growth of Galaxy Stellar Haloes over 0.2 ≤ <i>z</i> ≤ 1.1
The Growth of Galaxy Stellar Haloes over 0.2 ≤ <i>z</i> ≤ 1.1 Open
Galaxies are predicted to assemble their stellar haloes through the accretion of stellar material from interactions with their cosmic environment. Observations that trace stellar halo buildup probe the processes that drive galaxy size and …
View article: The Connection between Galaxy Mergers, Star Formation, and Active Galactic Nuclei Activity in the HSC-SSP
The Connection between Galaxy Mergers, Star Formation, and Active Galactic Nuclei Activity in the HSC-SSP Open
Internal gas inflows driven by galaxy mergers are considered to enhance star formation rates (SFRs), fuel supermassive black hole growth, and stimulate active galactic nuclei (AGNs). However, quantifying these phenomena remains a challenge…
View article: In Search of the First Stars: An Ultra-compact and Very-low-metallicity Ly<i>α</i> Emitter Deep within the Epoch of Reionization
In Search of the First Stars: An Ultra-compact and Very-low-metallicity Ly<i>α</i> Emitter Deep within the Epoch of Reionization Open
We present JWST observations of a gravitationally lensed, extremely metal-poor galaxy at redshift z = 8.203 ± 0.001 from the CANUCS survey. Based on the low oxygen to Balmer line ratios, we infer a gas-phase metallicity of 12 + log(O/H) = …
View article: Earliest Galaxy Evolution in the CANUCS+Technicolor fields: Galaxy Properties at $z\sim10-16$ seen with the Full NIRCam Medium and Broad Band Filters
Earliest Galaxy Evolution in the CANUCS+Technicolor fields: Galaxy Properties at $z\sim10-16$ seen with the Full NIRCam Medium and Broad Band Filters Open
We present a sample of $z_{\rm phot}\sim10-16$ galaxies by exploiting one of the richest JWST NIRCam imaging data, taken in the CANUCS survey in Cycle 1 and the Technicolor (TEC) survey in Cycle 2. The combination of the CANUCS+TEC provide…
View article: Effects of Environment on the Size Evolution of Quiescent Galaxies: Comparing Galaxies in Clusters and in the Field at Two Rest-frame Wavelengths
Effects of Environment on the Size Evolution of Quiescent Galaxies: Comparing Galaxies in Clusters and in the Field at Two Rest-frame Wavelengths Open
We investigate the impact of environment on quiescent galaxy (QG) size evolution using the CLAUDS+HSC imaging covering 18.6 deg 2 in five broad filters ( Ugriz ) and the effective radius of a single-Sérsic fit as a proxy for galaxy size. W…
View article: RIDEN pilot survey: broad-band selection of candidate quasars with extended Lyman-α nebulae using CLAUDS–HSC-SSP–DUNES2 joint data
RIDEN pilot survey: broad-band selection of candidate quasars with extended Lyman-α nebulae using CLAUDS–HSC-SSP–DUNES2 joint data Open
The Vera C. Rubin Observatory will conduct the Legacy Survey of Space and Time (LSST), delivering deep, multi-band ($ugrizy$) imaging data across 18 000 square deg over the next decade. Before this ultra-wide-field survey, we constructed a…
View article: RIDEN pilot survey: broad-band selection of candidate quasars with extended Lyman-$α$ nebulae using CLAUDS-HSC-SSP-DUNES$^2$ joint data
RIDEN pilot survey: broad-band selection of candidate quasars with extended Lyman-$α$ nebulae using CLAUDS-HSC-SSP-DUNES$^2$ joint data Open
The Vera C. Rubin Observatory will conduct the Legacy Survey of Space and Time (LSST), delivering deep, multi-band ($ugrizy$) imaging data across 18,000 square degrees over the next decade. Before this ultra-wide-field survey, we construct…
View article: Possible environmental quenching in an interacting little red dot pair at <i>z</i> ∼ 7
Possible environmental quenching in an interacting little red dot pair at <i>z</i> ∼ 7 Open
We report the discovery of a z ∼ 7 group of galaxies that contains two little red dots (LRDs) just 3.3 kpc apart, along with three potential satellite galaxies, as part of the Canadian NIRISS Unbiased Cluster Survey (CANUCS). The spectral …
View article: Selection of high-redshift Lyman-Break Galaxies from broadband and wide photometric surveys
Selection of high-redshift Lyman-Break Galaxies from broadband and wide photometric surveys Open
In this paper, we investigate the possibility of selecting high-redshift Lyman-Break Galaxies (LBG) using current and future broadband wide photometric surveys, such as the Ultraviolet Near Infrared Optical Northern Survey (UNIONS) or the …
View article: Counting Little Red Dots at $z<4$ with Ground-based Surveys and Spectroscopic Follow-up
Counting Little Red Dots at $z<4$ with Ground-based Surveys and Spectroscopic Follow-up Open
Little red dots (LRDs) are a population of red, compact objects discovered by JWST at $z>4$. At $44$ to $\sim10^{-5.3}\,\mathrm{cMpc^{-3}}$ at $2.7
View article: Improving Photometric Redshifts of Epoch of Reionization Galaxies: A New Empirical Transmission Curve with Neutral Hydrogen Damping Wing Ly<i>α</i> Absorption
Improving Photometric Redshifts of Epoch of Reionization Galaxies: A New Empirical Transmission Curve with Neutral Hydrogen Damping Wing Ly<i>α</i> Absorption Open
We present a new analytical model for the attenuation to Epoch of Reionization (EoR) galaxies by proximate neutral hydrogen gas. Many galaxy spectra in the EoR taken by JWST have shown a flux deficit at wavelengths just redward of the Lyma…
View article: CANUCS/Technicolor: JWST Medium Band Photometry Finds Half of the Star Formation at $z>7.5$ is Obscured
CANUCS/Technicolor: JWST Medium Band Photometry Finds Half of the Star Formation at $z>7.5$ is Obscured Open
We present a sample of 146 high-redshift ($z>7.5$) galaxies from the CANUCS/Technicolor surveys, showcasing photometry in every wide- and medium-band NIRCam filter in addition to ancillary HST data sampling $0.4-5 μm$ (22 JWST bands out of…
View article: <i>Euclid</i> preparation
<i>Euclid</i> preparation Open
The Cosmic Dawn Survey (DAWN survey) provides multiwavelength (UV/optical to mid-IR) data across the combined 59 deg 2 of the Euclid Deep and Auxiliary fields (EDFs and EAFs). In this work, the first public data release from the DAWN surve…
View article: CANUCS: Constraining the MACS J0416.1-2403 strong lensing model with JWST NIRISS, NIRSpec, and NIRCam
CANUCS: Constraining the MACS J0416.1-2403 strong lensing model with JWST NIRISS, NIRSpec, and NIRCam Open
Context. Strong gravitational lensing in galaxy clusters has become an essential tool in astrophysics, as it allows one to directly probe the dark matter distribution and study magnified background sources. The precision and reliability of…
View article: In Search of the First Stars: An Ultra-Compact and Very Low Metallicity Lyman-$α$ Emitter Deep Within the Epoch of Reionization
In Search of the First Stars: An Ultra-Compact and Very Low Metallicity Lyman-$α$ Emitter Deep Within the Epoch of Reionization Open
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 the low oxygen to Balmer line ratios we infer a gas-phase metallicity of $12+{\rm l…
View article: JWST, ALMA, and Keck Spectroscopic Constraints on the UV Luminosity Functions at <i>z</i> ∼ 7–14: Clumpiness and Compactness of the Brightest Galaxies in the Early Universe
JWST, ALMA, and Keck Spectroscopic Constraints on the UV Luminosity Functions at <i>z</i> ∼ 7–14: Clumpiness and Compactness of the Brightest Galaxies in the Early Universe Open
We present the number densities and physical properties of the bright galaxies spectroscopically confirmed at z ∼ 7–14. Our sample is composed of 60 galaxies at z spec ∼ 7–14, including recently confirmed galaxies at z spec = 12.34–14.18 w…
View article: Cluster Candidates with Massive Quiescent Galaxies at z ∼ 2
Cluster Candidates with Massive Quiescent Galaxies at z ∼ 2 Open
Galaxy clusters are crucial to understanding the role of the environment in galaxy evolution. However, due to their rarity, only a limited number of clusters have been identified at z ≳ 2. In this paper, we report a discovery of seven clus…
View article: Galaxy properties from the outskirts to the core of a protocluster at <i>z</i> = 3.70
Galaxy properties from the outskirts to the core of a protocluster at <i>z</i> = 3.70 Open
We study the dependence of galaxy properties on their spatial position within a protocluster by carrying out follow-up spectroscopy on a protocluster candidate selected from the wide-field imaging of the Hyper SuprimeCam Subaru Strategic P…
View article: Possible environmental quenching in an interacting little red dot pair at $z\sim7$
Possible environmental quenching in an interacting little red dot pair at $z\sim7$ Open
We report the discovery of a $z\sim7$ group of galaxies that contains two little red dots (LRDs) just 3.3 kpc apart, along with three potential satellite galaxies, as part of the Canadian NIRISS Unbiased Cluster Survey (CANUCS). The spectr…
View article: <i>Euclid</i> preparation
<i>Euclid</i> preparation Open
Euclid will provide deep near-infrared (NIR) imaging to ∼26.5 AB magnitude over ∼59 deg 2 in its deep and auxiliary fields. The Cosmic DAWN survey combines dedicated and archival UV–NIR observations to provide matched depth multiwavelength…