Daniel P. Stark
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View article: Under Pressure: Decoding the Effect of High Densities on Derived Nebular Properties
Under Pressure: Decoding the Effect of High Densities on Derived Nebular Properties Open
Recent JWST observations have uncovered a population of compact, high-redshift ( z > 6) galaxies exhibiting extreme nebular conditions and enhanced nitrogen abundances that challenge standard chemical evolution paradigms. We present a join…
View article: REBELS-IFU: dust build-up in massive galaxies at redshift 7
REBELS-IFU: dust build-up in massive galaxies at redshift 7 Open
In recent years, observations with the James Webb Space Telescope (JWST) have started to map out the rapid metal enrichment of the early Universe, while (sub)millimetre observations have simultaneously begun to reveal the ubiquity of dust …
View article: Consistent Gas-phase C/O Abundances from UV and Optical Emission Lines: A Robust Scale for Chemical Evolution across Cosmic Time
Consistent Gas-phase C/O Abundances from UV and Optical Emission Lines: A Robust Scale for Chemical Evolution across Cosmic Time Open
The carbon-to-oxygen (C/O) abundance ratio is a valuable tracer of star formation history, as C and O enrichment occurs on different timescales. However, measurements based on ultraviolet (UV) collisionally excited lines and those based on…
View article: Deep JWST spectroscopy of galaxies in a candidate ionized bubble at $z = 8.7$: probing reionization at pMpc scales with Ly$α$ emission
Deep JWST spectroscopy of galaxies in a candidate ionized bubble at $z = 8.7$: probing reionization at pMpc scales with Ly$α$ emission Open
Strong Ly$α$ emission observed from galaxies when the Universe is expected to be highly neutral is thought to trace large ionized regions that facilitate the transmission of Ly$α$ through the IGM. In this work, we use deep JWST Ly$α$ spect…
View article: The Growth of Dust in Galaxies in the First Billion Years with Applications to Blue Monsters
The Growth of Dust in Galaxies in the First Billion Years with Applications to Blue Monsters Open
A combination of JWST observations at z~12-14 and ALMA observations of extremely dust-rich systems at z~6 has demonstrated that dust grows extremely fast in the early Universe, with galaxies amassing up to 10^7 Msun of dust in just 500 Myr…
View article: The AURORA Survey: The Nebular Attenuation Curve of a Galaxy at <i>z</i> = 4.41 from Ultraviolet to Near-infrared Wavelengths
The AURORA Survey: The Nebular Attenuation Curve of a Galaxy at <i>z</i> = 4.41 from Ultraviolet to Near-infrared Wavelengths Open
We use JWST/NIRSpec observations from the Assembly of Ultradeep Rest-optical Observations Revealing Astrophysics survey to constrain the shape of the nebular attenuation curve of a star-forming galaxy at z = 4.41, GOODSN-17940. We utilize …
View article: The AURORA Survey: Robust Helium Abundances at High Redshift Reveal A Subpopulation of Helium-Enhanced Galaxies in the Early Universe
The AURORA Survey: Robust Helium Abundances at High Redshift Reveal A Subpopulation of Helium-Enhanced Galaxies in the Early Universe Open
We present the first robust helium (He) abundance measurements in star-forming galaxies at redshifts $1.6\lesssim z\lesssim 3.3$ using deep, moderate-resolution JWST/NIRSpec spectroscopy from the AURORA survey. We establish a High$-z$ HeI …
View article: The JWST Spectroscopic Properties of Galaxies at $z=9-14$
The JWST Spectroscopic Properties of Galaxies at $z=9-14$ Open
We characterize the JWST spectra of $61$ galaxies at $z=9-14$, including $30$ newly-confirmed galaxies. We directly compare the $z>9$ spectroscopic properties against $401$ galaxies at $69$ galaxies. Our dataset indicates that the emission…
View article: Mapping reionization bubbles in JWST era
Mapping reionization bubbles in JWST era Open
The James Webb Space Telescope (JWST) is discovering an increasing number of galaxies well into the early stages of the epoch of reionization (EoR). Many of these galaxies are clustered with strong Lyman-alpha (Ly α ) emission, which indic…
View article: The Impact of Galaxy Overdensities and Ionized Bubbles on Ly$α$ Emission at $z\sim7.0-8.5$
The Impact of Galaxy Overdensities and Ionized Bubbles on Ly$α$ Emission at $z\sim7.0-8.5$ Open
Ly$α$ spectroscopy with JWST is opening a new window on the sizes of ionized bubbles through the reionization epoch. Theoretical expectations suggest typical bubble radii should be 0.6-1.5 pMpc at $z\simeq 7$, assuming neutral hydrogen fra…
View article: Shining a Light on the Connections between Galactic Outflows Seen in Absorption and Emission Lines
Shining a Light on the Connections between Galactic Outflows Seen in Absorption and Emission Lines Open
Galactic outflows provide important feedback effects to regulate the evolution of host galaxies. Two primary diagnostics of outflows are broad and/or blueshifted emission and absorption lines. Even though well-established methods exist to …
View article: JADES: Differing assembly histories of galaxies
JADES: Differing assembly histories of galaxies Open
We used deep NIRSpec spectroscopic data from the JADES survey to derive the star formation histories (SFHs) of a sample of 200 galaxies at 0.6 < z < 11 that span stellar masses from 10 6 to 10 9.5 M ⊙ . We found that galaxies at high redsh…
View article: REBELS-IFU: dust attenuation curves of 12 massive galaxies at <i>z</i> ≃ 7
REBELS-IFU: dust attenuation curves of 12 massive galaxies at <i>z</i> ≃ 7 Open
We present measurements of the dust attenuation curves of 12 massive ($9~<~\log$($M_{\star }$/${\rm M}_{\odot }$) $<~10$) Lyman-break galaxies at $z=6.5 \!\!-\!\! 7.7$ derived from JWST NIRSpec integral field unit spectroscopy. The g…
View article: The rest-UV spectral properties of dwarf galaxies at <i>z</i> ∼ 2
The rest-UV spectral properties of dwarf galaxies at <i>z</i> ∼ 2 Open
Rest-utraviolet (UV) spectroscopy can constrain properties of the stellar populations, outflows, covering fractions, and can indirectly constrain the Lyman continuum escape fraction of galaxies. Many works have studied the rest-UV spectra …
View article: The Ultraviolet Slopes of Early Universe Galaxies: The Impact of Bursty Star Formation, Dust, and Nebular Continuum Emission
The Ultraviolet Slopes of Early Universe Galaxies: The Impact of Bursty Star Formation, Dust, and Nebular Continuum Emission Open
JWST has enabled the detection of the ultraviolet (UV) continuum of galaxies at z > 10, revealing extremely blue, potentially dust-free galaxies. However, interpreting UV spectra is complicated by the well-known degeneracy between stellar …
View article: The AURORA Survey: An Extraordinarily Mature, Star-forming Galaxy at <i>z</i> ∼ 7
The AURORA Survey: An Extraordinarily Mature, Star-forming Galaxy at <i>z</i> ∼ 7 Open
We present the properties of a massive, large, dusty, metal-rich, star-forming galaxy at z spec = 6.73. GOODSN-100182 was observed with JWST/NIRSpec as part of the Assembly of Ultradeep Rest-optical Observations Revealing Astrophysics (AUR…
View article: Spatially Resolved Galactic Winds at Cosmic Noon: Outflow Kinematics and Mass Loading in a Lensed Star-forming Galaxy at <i>z</i> = 1.87
Spatially Resolved Galactic Winds at Cosmic Noon: Outflow Kinematics and Mass Loading in a Lensed Star-forming Galaxy at <i>z</i> = 1.87 Open
We study the spatially resolved outflow properties of CSWA13, an intermediate-mass ( M * = 10 9 M ⊙ ), gravitationally lensed star-forming galaxy at z = 1.87. We use Keck/KCWI to map outflows in multiple rest-frame UV interstellar medium (…
View article: The AURORA Survey: A New Era of Emission-line Diagrams with JWST/NIRSpec
The AURORA Survey: A New Era of Emission-line Diagrams with JWST/NIRSpec Open
We present results on the emission-line properties of z = 1.4–7.5 star-forming galaxies in the Assembly of Ultradeep Rest-optical Observations Revealing Astrophysics (AURORA) Cycle 1 JWST/NIRSpec program. Based on its depth, continuous wav…
View article: The AURORA Survey: The Evolution of Multi-phase Electron Densities at High Redshift
The AURORA Survey: The Evolution of Multi-phase Electron Densities at High Redshift Open
We present an analysis of deep $\textit{JWST}$/NIRSpec spectra of star-forming galaxies at $z\simeq1.4-10$, observed as part of the AURORA survey. We infer median low-ionization electron densities of $268_{-49}^{+45}~\rm cm^{-3}$, $350_{-7…
View article: Constraints on the $z\sim6-13$ intergalactic medium from JWST spectroscopy of Lyman-alpha damping wings in galaxies
Constraints on the $z\sim6-13$ intergalactic medium from JWST spectroscopy of Lyman-alpha damping wings in galaxies Open
JWST provides a unique dataset to study reionization's earliest stages, promising insights into the first galaxies. Many JWST/NIRSpec prism spectra reveal smooth Lyman-alpha breaks in z>5 galaxies, implying damping wing scattering by neutr…
View article: REBELS-IFU: Dust Build-up in Massive Galaxies at Redshift 7
REBELS-IFU: Dust Build-up in Massive Galaxies at Redshift 7 Open
In recent years, observations with the JWST have started to map out the rapid metal enrichment of the early Universe, while (sub)millimeter observations have simultaneously begun to reveal the ubiquity of dust beyond $z\gtrsim6$. However, …
View article: Mapping reionization bubbles in the JWST era II: inferring the position and characteristic size of individual bubbles
Mapping reionization bubbles in the JWST era II: inferring the position and characteristic size of individual bubbles Open
The James Webb Space Telescope (JWST) is discovering an increasing number of galaxies well into the early stages of the Epoch of Reionization (EoR). Many of these galaxies are clustered with strong Lyman alpha (Ly$α$) emission, motivating …
View article: The $z \gtrsim 9$ galaxy UV luminosity function from the JWST Advanced Deep Extragalactic Survey: insights into early galaxy evolution and reionization
The $z \gtrsim 9$ galaxy UV luminosity function from the JWST Advanced Deep Extragalactic Survey: insights into early galaxy evolution and reionization Open
The high-redshift UV luminosity function provides important insights into the evolution of early galaxies. JWST has revealed an unexpectedly large population of bright ($M_\mathrm{UV} \lesssim -20$) galaxies at $z\gtrsim10$, implying funda…
View article: Efficient Ionizers with Low H$\boldsymbolβ$+[OIII] Equivalent Widths: JADES Spectroscopy of a Peculiar High-z Population
Efficient Ionizers with Low H$\boldsymbolβ$+[OIII] Equivalent Widths: JADES Spectroscopy of a Peculiar High-z Population Open
Early JWST photometric studies discovered a population of UV faint ($\rm 700$Å) exclude the most metal-poor efficient ionizers and favor 1) more chemically enriched systems with comparable extreme radiation fields and 2) older starbursting…
View article: CLASSY. XI. Tracing Neutral Gas Properties Using UV Absorption Lines and 21 cm Observations*
CLASSY. XI. Tracing Neutral Gas Properties Using UV Absorption Lines and 21 cm Observations* Open
Rest-frame far-ultraviolet (FUV) observations from JWST are revolutionizing our understanding of the high- z galaxies that drove reionization and the mechanisms by which they accomplished it. To fully interpret these observations, we must …
View article: Extreme emission line galaxies detected in JADES <i>JWST</i>/NIRSpec – I. Inferred galaxy properties
Extreme emission line galaxies detected in JADES <i>JWST</i>/NIRSpec – I. Inferred galaxy properties Open
Extreme emission line galaxies (EELGs) exhibit large equivalent widths (EW) in their rest-optical emission lines ([O iii]$\lambda 5007$ or H $\alpha$ rest-frame EW$\gt 750$ Å) which can be tied to a recent upturn in star formation rate (SF…
View article: The Burstiness of Star Formation at $z\sim6$: A Huge Diversity in the Recent Star Formation Histories of Very UV-faint Galaxies
The Burstiness of Star Formation at $z\sim6$: A Huge Diversity in the Recent Star Formation Histories of Very UV-faint Galaxies Open
IRAC data have long implied that early ($z\gtrsim6$) galaxies often have very high specific star formation rates (sSFR$\gtrsim$30 Gyr$^{-1}$), but JWST data have shown that at least some early galaxies are forming stars far less vigorously…
View article: The AURORA Survey: An Extraordinarily Mature, Star-forming Galaxy at $z\sim 7$
The AURORA Survey: An Extraordinarily Mature, Star-forming Galaxy at $z\sim 7$ Open
We present the properties of a massive, large, dusty, metal-rich, star-forming galaxy at z_spec=6.73. GOODSN-100182 was observed with JWST/NIRSpec as part of the AURORA survey, and is also covered by public multi-wavelength HST and JWST im…
View article: JADES NIRSpec initial data release for the <i>Hubble</i> Ultra Deep Field
JADES NIRSpec initial data release for the <i>Hubble</i> Ultra Deep Field Open
We describe the NIRSpec component of the JWST Deep Extragalactic Survey (JADES), and provide deep spectroscopy of 253 sources targeted with the NIRSpec micro-shutter assembly in the Hubble Ultra Deep Field and surrounding GOODS-South. The …
View article: Theoretical Strong-line Metallicity Diagnostics for the JWST Era
Theoretical Strong-line Metallicity Diagnostics for the JWST Era Open
The ratios of strong rest-frame optical emission lines are the dominant indicators of metallicities in high-redshift galaxies. Since typical strong-line-based metallicity indicators are calibrated on auroral lines at z = 0, their applicabi…