Search Publications
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…
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…
Inspiraling streams of enriched gas observed around a massive galaxy 11 billion years ago
Fan, Xiaohui; Cai, Zheng; Li, Qiong +19 more
Stars form in galaxies, from gas that has been accreted from the intergalactic medium. Simulations have shown that recycling of gas—the reaccretion of gas that was previously ejected from a galaxy—could sustain star formation in the early Universe. We observe the gas surrounding a massive galaxy at redshift 2.3 and detect emission lines from neutr…
A cosmic stream of atomic carbon gas connected to a massive radio galaxy at redshift 3.8
Lehnert, Matthew D.; De Breuck, Carlos; Mandelker, Nir +7 more
The growth of galaxies in the early Universe is driven by accretion of circum- and intergalactic gas. Simulations have predicted that steady streams of cold gas penetrate the dark matter halos of galaxies and provide the raw material necessary to sustain star formation. We report a filamentary stream of gas that extends for 100 kiloparsecs and con…
A massive stellar bulge in a regularly rotating galaxy 1.2 billion years after the Big Bang
Maiolino, Roberto; Zhang, Zhi-Yu; De Breuck, Carlos +5 more
Cosmological models predict that galaxies forming in the early Universe experience a chaotic phase of gas accretion and star formation, followed by gas ejection due to feedback processes. Galaxy bulges may assemble later via mergers or internal evolution. Here we present submillimeter observations (with spatial resolution of 700 parsecs) of ALESS …
A transient radio source consistent with a merger-triggered core collapse supernova
Kulkarni, S. R.; Hallinan, G.; Horesh, A. +10 more
A core collapse supernova occurs when exothermic fusion ceases in the core of a massive star, which is typically caused by exhaustion of nuclear fuel. Theory predicts that fusion could be interrupted earlier by merging of the star with a compact binary companion. We report a luminous radio transient, VT J121001+495647, found in the Very Large Arra…
An excess of small-scale gravitational lenses observed in galaxy clusters
Grillo, Claudio; Rosati, Piero; Meneghetti, Massimo +11 more
Cold dark matter (CDM) constitutes most of the matter in the Universe. The interplay between dark and luminous matter in dense cosmic environments, such as galaxy clusters, is studied theoretically using cosmological simulations. Observations of gravitational lensing are used to characterize the properties of substructures—the small-scale distribu…
Gravitational lensing reveals ionizing ultraviolet photons escaping from a distant galaxy
Mahler, Guillaume; Chisholm, John; Rigby, Jane R. +7 more
During the epoch of reionization, neutral gas in the early Universe was ionized by hard ultraviolet radiation emitted by young stars in the first galaxies. To do so, ionizing ultraviolet photons must escape from the host galaxy. We present Hubble Space Telescope observations of the gravitationally lensed post-reionization galaxy PSZ1-ARC G311.6602…