Search Publications
X-ray quasi-periodic eruptions from two previously quiescent galaxies
Gromadzki, M.; Salvato, M.; Buchner, J. +21 more
Quasi-periodic eruptions (QPEs) are very-high-amplitude bursts of X-ray radiation recurring every few hours and originating near the central supermassive black holes of galactic nuclei1,2. It is currently unknown what triggers these events, how long they last and how they are connected to the physical properties of the inner accretion f…
Normal, dust-obscured galaxies in the epoch of reionization
Inami, H.; Bowler, R. A. A.; De Looze, I. +26 more
Over the past decades, rest-frame ultraviolet (UV) observations have provided large samples of UV luminous galaxies at redshift (z) greater than 6 (refs. 1-3), during the so-called epoch of reionization. While a few of these UV-identified galaxies revealed substantial dust reservoirs4-7, very heavily dust-obscured sources at …
All-sky dynamical response of the Galactic halo to the Large Magellanic Cloud
Conroy, Charlie; Johnson, Benjamin D.; Naidu, Rohan P. +4 more
Gravitational interactions between the Large Magellanic Cloud (LMC) and the stellar and dark matter halo of the Milky Way are expected to give rise to disequilibrium phenomena in the outer Milky Way1-7. A local wake is predicted to trail the orbit of the LMC, and a large-scale overdensity is predicted to exist across a large area of the…
A highly magnetized and rapidly rotating white dwarf as small as the Moon
Kulkarni, S. R.; Duev, Dmitry A.; Burdge, Kevin B. +15 more
White dwarfs represent the last stage of evolution of stars with mass less than about eight times that of the Sun and, like other stars, are often found in binaries1,2. If the orbital period of the binary is short enough, energy losses from gravitational-wave radiation can shrink the orbit until the two white dwarfs come into contact an…
A bright γ-ray flare interpreted as a giant magnetar flare in NGC 253
Mitrofanov, I.; Hurley, K.; von Kienlin, A. +33 more
Soft γ-ray repeaters exhibit bursting emission in hard X-rays and soft γ-rays. During the active phase, they emit random short (milliseconds to several seconds long), hard-X-ray bursts, with peak luminosities1 of 1036 to 1043 erg per second. Occasionally, a giant flare with an energy of around 1044 to 10…
r-Process elements from magnetorotational hypernovae
Schmidt, B. P.; Da Costa, G. S.; Marino, A. F. +11 more
Neutron-star mergers were recently confirmed as sites of rapid-neutron-capture (r-process) nucleosynthesis1-3. However, in Galactic chemical evolution models, neutron-star mergers alone cannot reproduce the observed element abundance patterns of extremely metal-poor stars, which indicates the existence of other sites of r-process nucleo…
Large metallicity variations in the Galactic interstellar medium
Jenkins, Edward B.; Petitjean, Patrick; Fox, Andrew J. +5 more
The interstellar medium (ISM) comprises gases at different temperatures and densities, including ionized, atomic and molecular species, and dust particles1. The neutral ISM is dominated by neutral hydrogen2 and has ionization fractions of up to eight per cent3. The concentration of chemical elements heavier than he…
The diffuse γ-ray background is dominated by star-forming galaxies
Krumholz, Mark R.; Crocker, Roland M.; Roth, Matt A. +1 more
The Fermi Gamma-ray Space Telescope has revealed a diffuse γ-ray background at energies from 0.1 gigaelectronvolt to 1 teraelectronvolt, which can be separated into emission from our Galaxy and an isotropic, extragalactic component1. Previous efforts to understand the latter have been hampered by the lack of physical models capable of p…
Quenching of star formation from a lack of inflowing gas to galaxies
Richard, Johan; van Dokkum, Pieter G.; Mowla, Lamiya +16 more
Star formation in half of massive galaxies was quenched by the time the Universe was 3 billion years old1. Very low amounts of molecular gas seem to be responsible for this, at least in some cases2-7, although morphological gas stabilization, shock heating or activity associated with accretion onto a central supermassive blac…
Light bending and X-ray echoes from behind a supermassive black hole
Brandt, W. N.; Costantini, E.; Blandford, R. D. +2 more
The innermost regions of accretion disks around black holes are strongly irradiated by X-rays that are emitted from a highly variable, compact corona, in the immediate vicinity of the black hole1-3. The X-rays that are seen reflected from the disk4, and the time delays, as variations in the X-ray emission echo or `reverberate…