Search Publications
Strong damped Lyman-α absorption in young star-forming galaxies at redshifts 9 to 11
Finkelstein, Steven L.; Arrabal Haro, Pablo; Heintz, Kasper E. +18 more
Primordial neutral atomic gas, mostly composed of hydrogen, is the raw material for star formation in galaxies. However, there are few direct constraints on the amount of neutral atomic hydrogen (H I) in galaxies at early cosmic times. We analyzed James Webb Space Telescope (JWST) near-infrared spectroscopy of distant galaxies, at redshifts ≳8. Fr…
A pulsar in a binary with a compact object in the mass gap between neutron stars and black holes
Cadelano, Mario; Pallanca, Cristina; Freire, Paulo C. C. +22 more
Some compact objects observed in gravitational wave events have masses in the gap between known neutron stars (NSs) and black holes (BHs). The nature of these mass gap objects is unknown, as is the formation of their host binary systems. We report pulsar timing observations made with the Karoo Array Telescope (MeerKAT) of PSR J0514‑4002E, an eccen…
A far-ultraviolet–driven photoevaporation flow observed in a protoplanetary disk
Hartigan, Patrick; Zhang, Yong; Gordon, Karl D. +144 more
Most low-mass stars form in stellar clusters that also contain massive stars, which are sources of far-ultraviolet (FUV) radiation. Theoretical models predict that this FUV radiation produces photodissociation regions (PDRs) on the surfaces of protoplanetary disks around low-mass stars, which affects planet formation within the disks. We report Ja…
In situ observations of large-amplitude Alfvén waves heating and accelerating the solar wind
Stawarz, Julia E.; Kasper, Justin C.; Louarn, Philippe +16 more
After leaving the Sun’s corona, the solar wind continues to accelerate and cools, but more slowly than expected for a freely expanding adiabatic gas. Alfvén waves are perturbations of the interplanetary magnetic field that transport energy. We use in situ measurements from the Parker Solar Probe and Solar Orbiter spacecraft to investigate a stream…
Abundant hydrocarbons in the disk around a very-low-mass star
Waters, L. B. F. M.; Olofsson, G.; Kamp, I. +40 more
Very-low-mass stars (those less than 0.3 solar masses) host orbiting terrestrial planets more frequently than other types of stars. The compositions of those planets are largely unknown but are expected to relate to the protoplanetary disk in which they form. We used James Webb Space Telescope mid-infrared spectroscopy to investigate the chemical …
Emission lines due to ionizing radiation from a compact object in the remnant of Supernova 1987A
Fox, O. D.; Blommaert, J. A. D. L.; Larsson, J. +31 more
The nearby Supernova 1987A was accompanied by a burst of neutrino emission, which indicates that a compact object (a neutron star or black hole) was formed in the explosion. There has been no direct observation of this compact object. In this work, we observe the supernova remnant with JWST spectroscopy, finding narrow infrared emission lines of a…
A magnetic massive star has experienced a stellar merger
Smoker, J. V.; Shenar, T.; Sana, H. +13 more
Massive stars (those ≥8 solar masses at formation) have radiative envelopes that cannot sustain a dynamo, the mechanism that produces magnetic fields in lower-mass stars. Despite this, approximately 7% of massive stars have observed magnetic fields, the origin of which is debated. We used multi-epoch interferometric and spectroscopic observations …
Sun-like stars produce superflares roughly once per century
Solanki, Sami K.; Notsu, Yuta; Maehara, Hiroyuki +7 more
Stellar superflares are energetic outbursts of electromagnetic radiation that are similar to solar flares but release more energy, up to 1036 erg on main-sequence stars. It is unknown whether the Sun can generate superflares and, if so, how often they might occur. We used photometry from the Kepler space observatory to investigate super…
A magnified compact galaxy at redshift 9.51 with strong nebular emission lines
Koekemoer, Anton M.; Treu, Tommaso; Broadhurst, Tom +21 more
Ultraviolet light from early galaxies is thought to have ionized gas in the intergalactic medium. However, there are few observational constraints on this epoch because of the faintness of those galaxies and the redshift of their optical light into the infrared. We report the observation, in JWST imaging, of a distant galaxy that is magnified by g…
Constraints on the Hubble constant from supernova Refsdal's reappearance
Treu, Tommaso; Broadhurst, Tom; Filippenko, Alexei V. +27 more
The gravitationally lensed supernova Refsdal appeared in multiple images produced through gravitational lensing by a massive foreground galaxy cluster. After the supernova appeared in 2014, lens models of the galaxy cluster predicted that an additional image of the supernova would appear in 2015, which was subsequently observed. We use the time de…