Search Publications
Positron annihilation in the nuclear outflows of the Milky Way
Ruiter, Ashley J.; Panther, Fiona H.; Seitenzahl, Ivo R. +2 more
Observations of soft gamma rays emanating from the Milky Way from SPI/INTEGRAL reveal the annihilation of ∼2 × 1043 positrons every second in the Galactic bulge. The origin of these positrons, which annihilate to produce a prominent emission line centred at 511 keV, has remained mysterious since their discovery almost 50 yr ago. A plaus…
Evolution of Cometary Dust Particles to the Orbit of the Earth: Particle Size, Shape, and Mutual Collisions
Ishiguro, Masateru; Yang, Hongu
In this study, we numerically investigated the orbital evolution of cometary dust particles, with special consideration of the initial size-frequency distribution (SFD) and different evolutionary tracks according to the initial orbit and particle shape. We found that close encounters with planets (mostly Jupiter) are the dominating factor determin…
The interaction of the halo around the butterfly planetary nebula NGC 650-1 with the interstellar medium
Guerrero, M. A.; Ramos-Larios, G.; Sabin, L. +7 more
With its bright and wide equatorial waist seen almost edge-on (`the butterfly body') and the faint and broad bipolar extensions (`the butterfly wings'), NGC 650-1 is the archetypical example of bipolar planetary nebula (PN) with butterfly morphology. We present here deep high-resolution broad- and narrow-band optical images that expose the rich an…
Star formation and gas inflows in the OH megamaser galaxy IRAS03056+2034
Robinson, Andrew; Baum, Stefi; Storchi-Bergmann, Thaisa +6 more
We have obtained observations of the OH megamaser galaxy IRAS03056+2034 using the Gemini Multi-Object Spectrograph (GMOS) Integral Field Unit (IFU), Very Large Array (VLA), and Hubble Space Telescope (HST). The HST data reveals spiral arms containing knots of emission associated with star-forming regions. The GMOS-IFU data cover the spectral range…
Artificial intelligence unfolding for space radiation monitor data
Daglis, I. A.; Sandberg, I.; Evans, H. +5 more
The reliable and accurate calculation of incident particle radiation fluxes from space radiation monitor measurements, i.e. count-rates, is of great interest and importance. Radiation monitors are relatively simple and easy to implement instruments found on board multiple spacecrafts and can thus provide information about the radiation environment…
In Situ Generation of Transverse Magnetohydrodynamic Waves from Colliding Flows in the Solar Corona
Antolin, Patrick; Pagano, Paolo; Nakariakov, Valery M. +1 more
Transverse magnetohydrodynamic (MHD) waves permeate the solar atmosphere and are a candidate for coronal heating. However, the origin of these waves is still unclear. In this Letter, we analyze coordinated observations from Hinode/Solar Optical Telescope (SOT) and Interface Region Imaging Spectrograph ( IRIS) of a prominence/coronal rain loop-like…
Europa’s Optical Aurora
Brown, Michael E.; de Kleer, Katherine
Auroral emissions provide opportunities to study the tenuous atmospheres of solar system satellites, revealing the presence and abundance of molecular and atomic species as well as their spatial and temporal variability. Far-UV aurorae have been used for decades to study the atmospheres of the Galilean satellites. Here we present the first detecti…
Gaia-ESO Survey: INTRIGOSS—A New Library of High-resolution Synthetic Spectra
Jofré, Paula; Flaccomio, Ettore; Koposov, Sergey E. +19 more
We present a high-resolution synthetic spectral library, INTRIGOSS, designed for studying FGK stars. The library is based on atmosphere models computed with specified individual element abundances via ATLAS12 code. Normalized SPectra (NSPs) and surface Flux SPectra (FSP) in the wavelength range 4830-5400 Å were computed with the SPECTRUM code. INT…
Formation of the UV Spectrum of Molecular Hydrogen in the Sun
Judge, P. G.; Jaeggli, S. A.; Daw, A. N.
Ultraviolet (UV) lines of molecular hydrogen have been observed in solar spectra for almost four decades, but the behavior of the molecular spectrum and its implications for solar atmospheric structure are not fully understood. Data from the High-Resolution Telescope Spectrometer (HRTS) instrument revealed that H2 emission forms in part…
Substellar and low-mass dwarf identification with near-infrared imaging space observatories
Ryan, R.; Holwerda, B. W.; Smit, R. +9 more
Aims: We aim to evaluate the near-infrared colors of brown dwarfs as observed with four major infrared imaging space observatories: the Hubble Space Telescope (HST), the James Webb Space Telescope (JWST), the Euclid mission, and the WFIRST telescope.
Methods: We used the SPLAT SPEX/ISPEX spectroscopic library to map out the colors of the…