arXiv subjects

Joseph Havens

Publications and source records attributed to Joseph Havens.

3 recordsLinked to original sources

arXiv2026

Constraining Dust Attenuation Curves in Star-Forming Galaxies at Cosmic Noon Using Multiple Emission Line Ratios

Dust attenuation remains a dominant systematic uncertainty in measurements of an emission line, and therefore galaxies properties derived from the emission lines such as star formation rates. Corrections based only on the Balmer decrement require an assumed attenuation-curve slope, even though that slope varies among galaxies. We use JWST/NIRSpec spectroscopy from JADES to constrain effective dust attenuation curves for 386 star-forming galaxies at $0.5\leq z\leq7$. For each galaxy, we combine H$α$, H$β$, and one additional hydrogen recombination line and solve for the normalization $τ_V$ and slope $n$ of a power-law attenuation curve, allowing the slope to vary from galaxy to galaxy. We found slopes and normalization span a broad range even for galaxies at similar redshifts. Additionally, our method using Paschen transitions provided substantially greater constraints the attenuation-curve slope than Balmer-only combinations. When comparing to SMC-like or Calzetti-like corrections we find our method produces more consistent star formation rates with less scatter. These improved dust corrections provide an avenue to better describe star formation rates in the epoch of peak star formation and the early universe.

astro-ph.GA↗

arXiv2026

Cosmic Collisions I: Optical Morphologies for MIRI-selected galaxies from the PRIMER survey

We present the first results of visual morphology classifications from the Cosmic Collisions project, comprising 14,657 galaxies from the JWST Public Release IMaging for Extragalactic Research (PRIMER) survey. The sample consists of galaxies detected with MIRI F770W and spans the epoch of peak cosmic star formation (1 2. This inverts findings from optical selection, which shows galaxies becoming more bulge-dominated and elliptical over cosmic time. In addition, we identify a population of galaxies with disk-like optical morphologies and luminous mid-IR point-source cores that may represent obscured AGN candidates, offering a promising path to identify AGNs based on imaging alone. Comparison with visual classifications from HST imaging demonstrates the impact of JWST's improved sensitivity and resolution on the identification of galaxy structure and interactions, with systems previously identified by HST as compact, smooth, or featureless showing significant extended and internal structure in JWST. These results provide a foundation for future investigations into the connection between morphology, dust structure, star formation, and AGN activity.

astro-ph.GA↗

arXiv2026

JWST Observations of Starbursts: A Young Bubble in NGC 253's Central Starburst

We present a multi-wavelength analysis of a young bubble in the nuclear starburst of NGC 253 using new JWST MIRI-MRS observations together with archival ALMA (100, 350, 690 GHz) and Chandra data. The MIRI maps reveal a prominent bubble-like structure in both ionized and molecular emission lines. The bubble is spatially coincident with one of the least embedded massive young clusters detected with ALMA, suggesting that the cluster is driving the expansion. We measure a radius of $\sim 11.5 \pm 3.4$ pc and an expansion velocity of $\sim 90 \pm 44$ km s$^{-1}$, implying a dynamical age of $\sim 0.1 \pm 0.1$ Myr. Using RADEX modeling of multiple CO transitions, we infer a molecular mass in the range of $(1.3 \pm 0.3) \times 10^4$ to $(2.8 \pm 0.8) \times 10^5$ $M_\odot$. We derive a kinetic energy of order $10^{51}$-$10^{52}$ erg, consistent with mechanical input from Wolf-Rayet stellar winds or supernovae in a $\sim 10^6$ $M_\odot$ cluster. The existence of a large population of Wolf-Rayet stars or past supernovae is supported by the presence of coincident X-ray emission. Our results provide direct evidence that individual clusters in a nuclear environment can carve out coherent structures on parsec scales and inject significant energy and momentum into the surrounding interstellar medium, which can contribute to the nuclear outflow in NGC 253.

astro-ph.GA↗