485 citations · 1.2k across the 42 of their papers we have counts for
43 papers
Luminous Red Novae as shock-powered transients I: Electron-scattering wings and deviations from Case B
Albert Sneppen, Kenta Hotokezaka, Christopher M. Irwin
Luminous red novae (LRNe) are a class of optical transients resulting from the mergers of binary stars or common envelope events. The population displays heterogeneous light curves…
The metallicities of little red dot host galaxies: LRDs are metal poor, but not pristine
G. P. Nikopoulos, D. Watson, C. L. Pollock +4
Little Red Dots (LRDs) are a population of high-z sources discovered by JWST whose compactness, broad permitted lines, strong absorption features, continuum shapes and luminosities…
The nature of `little blue dots'
Albert Sneppen, Darach Watson, James H. Matthews +1
Previous Sirocco radiative-transfer models of gas-cocooned AGN predicted lower-column counterparts to little red dots (LRDs): compact, X-ray-weak sources with bluer continuum slope…
Quenching of X-ray emission in little red dots by both Compton-thick gas and high accretion rates
Albert Sneppen, Darach Watson, James H. Matthews +1
Little red dots (LRDs) are candidate high-redshift supermassive black holes accreting in dense gas. They remain undetected in X-rays. In previous work, we provided the first quanti…
Paschen Jumps in Little Red Dots: Evidence for Nebular Continua
Albert Sneppen, James H. Matthews, Darach Watson +6
''Little Red Dots'' (LRDs) are broad-line sources at high redshift, initially identified by their compact morphologies, red colours and prominent Balmer breaks. The origin of their…
Strontium and helium in the kilonova AT2017gfo: Origin of the 1μm feature constrained via NLTE calculations
Aayush Arya, Rasmus Damgaard, Albert Sneppen +4
Mergers of neutron stars are believed to be one of the primary sites for the synthesis of the universe's heavy elements via the rapid neutron capture process. AT2017gfo, the kilono…
A hot, nebular-dominated galaxy interacting with a pristine PopIII system uncovered by JWST
Henriette Reumert, Kasper E. Heintz, Clara L. Pollock +6
The discovery of galaxies with extremely strong nebular continuum emission at high redshifts provide novel, unique insights into the conditions under which the first super-massive…
Inside the cocoon: a comprehensive explanation of the spectra of Little Red Dots
A. Sneppen, D. Watson, J. H. Matthews +10
JWST has revealed a population of compact galaxies in the early Universe with broad emission lines and strong Balmer breaks; among them the so-called ''little red dots'' (LRDs). Th…
Spectroscopic characterization of a remarkable temporally varying, triple-lensed quasar at z=2.67
Charlie Lind-Thomsen, Kasper E. Heintz, Albert Sneppen +5
Gravitationally lensed quasars are viable cosmic tools for constraining a diversity of fundamental astrophysical phenomena; They enable identification of faint, low-mass supermassi…
Electron impact excitation of Te IV and V and Level Resolved R-matrix Photoionization of Te I - IV with application to modelling of AT2017gfo
Leo P. Mulholland, Catherine A. Ramsbottom, Connor P. Ballance +2
Spectral modelling of kilonovae (KNe) require large amounts of collisional excitation and photoionization atomic data for lowly ionised (neutral, singly and doubly ionised) species…
Evidence for inefficient dust production in a massive, metal-rich galaxy at uncovered by JWST and ALMA
Kasper E. Heintz, Darach Watson, Francesco Valentino +17
Recent observations have revealed a remarkably rapid buildup of cosmic dust in the interstellar medium (ISM) of high redshift galaxies, with complex dust compositions and large abu…
Light Travel Time Effects in Kilonova Models
F. McNeill, S. A. Sim, C. E. Collins +4
The extremely rapid evolution of kilonovae results in spectra that change on an hourly basis. These spectra are key to understanding the processes occurring within the event, but t…
JWST Spectroscopy of GRB 250702B: An Extremely Rare and Exceptionally Energetic Burst in a Dusty, Massive Galaxy at
Benjamin P. Gompertz, Andrew J. Levan, Tanmoy Laskar +25
We present follow-up observations of the day-long, repeating GRB 250702B with the Near Infrared Spectrograph (NIRSpec) on board the James Webb Space Telescope (JWST). Through the i…
JWST reveals a supernova following a gamma-ray burst at z 7.3
A. J. Levan, B. Schneider, E. Le Floc'h +50
The majority of energetic long-duration gamma-ray bursts (GRBs) are thought to arise from the collapse of massive stars, making them powerful tracers of star formation across cosmi…
The day-long, repeating GRB 250702BDE / EP250702a: A unique extragalactic transient
Andrew J. Levan, Antonio Martin-Carrillo, Tanmoy Laskar +42
Gamma-ray bursts (GRBs) are singular outbursts of high-energy radiation with durations typically lasting from milliseconds to minutes and, in extreme cases, a few hours. They are a…
Novel auroral line measurements extend the gradual offset of the FMR deep into the first Gyr of cosmic time
Clara L. Pollock, Rashmi Gottumukkala, Kasper E. Heintz +15
The mass assembly and chemical enrichment of the first galaxies provide key insights into their star-formation histories and the earliest stellar populations at cosmic dawn. Here w…
The optical constants and grain sizes of interstellar dust measured directly using the dust scattered x-ray halo of GRB 221009A
Albert Sneppen, Darach Watson
X-ray scattering is a powerful probe of the optical constants and grain size distribution of interstellar dust. Bright, transient sources are excellent tools for this, since they f…
A power spectral study of PHANGS galaxies with JWST MIRI: On the spatial scales of dust and PAHs
Charlie Lind-Thomsen, Albert Sneppen, Charles L. Steinhardt
The interstellar medium (ISM) consists of a diversity of structures across a range of spatial scales, intimately tied to galactic evolution. In this work, Fourier analysis is used…
Little red dots as young supermassive black holes in dense ionized cocoons
V. Rusakov, D. Watson, G. P. Nikopoulos +14
The James Webb Space Telescope (JWST) has uncovered many compact galaxies at high redshift with broad hydrogen and helium lines, including the enigmatic population of little red do…
Helium as an Indicator of the Neutron-Star Merger Remnant Lifetime and its Potential for Equation of State Constraints
Albert Sneppen, Oliver Just, Andreas Bauswein +9
The time until black hole formation in a binary neutron-star (NS) merger contains invaluable information about the nuclear equation of state (EoS) but has thus far been difficult t…
A massive, neutral gas reservoir permeating a galaxy proto-cluster after the reionization era
Kasper E. Heintz, Jake S. Bennett, Pascal A. Oesch +21
Galaxy clusters are the most massive, gravitationally-bound structures in the Universe, emerging through hierarchical structure formation of large-scale dark matter and baryon over…
Helium features are inconsistent with the spectral evolution of the kilonova AT2017gfo
Albert Sneppen, Rasmus Damgaard, Darach Watson +3
The spectral features observed in kilonovae (KNe) reveal the elemental composition and the velocity structures of matter ejected from neutron star mergers. In the spectra of the ki…
The JWST-PRIMAL Legacy Survey. A JWST/NIRSpec reference sample for the physical properties and Lyman- absorption and emission of galaxies at
K. E. Heintz, G. B. Brammer, D. Watson +45
One of the surprising early findings with JWST has been the discovery of a strong "roll-over" or a softening of the absorption edge of Ly in a large number of galaxies at ($z\gt…
Emergence hour-by-hour of -process features in the kilonova AT2017gfo
Albert Sneppen, Darach Watson, Rasmus Damgaard +4
The spectral features in the optical/near-infrared counterparts of neutron star mergers (kilonovae, KNe), evolve dramatically on hour timescales. To examine the spectral evolution…