Search Publications
The extremely X-ray luminous radio-loud quasar CFHQS J142952 + 544717 at z = 6.18 under Chandra high-angular resolution lens
Cheung, C. C.; Stawarz, Ł.; Siemiginowska, A. +6 more
We present the first X-ray observation at sub-arcsecond resolution of the high-redshift (z = 6.18) radio-loud quasar CFHQS J142952 + 544717 (J1429). The ~100 net-count 0.3-7 keV spectrum obtained from ~30 ks Chandra exposure is best fit by a single power-law model with a photon index Γ = 2.0 ± 0.2 and no indication of an intrinsic absorber, implyi…
Distillation of 56Fe in Ultramassive O-Ne White Dwarfs
Blouin, Simon; Caplan, Matthew E.; Freeman, Ian F.
When white dwarfs freeze, the plasma mixtures inside them undergo separation processes that can produce radical changes in the composition profile of the star. The abundance of neutron-rich elements, such as 22Ne or 56Fe, determines whether or not the first crystals are more or less dense than the surrounding fluid and thus w…
Physical Properties of 5000 Cool Large Magellanic Cloud Supergiants with Gaia XP Spectra: A Detailed Portrait of the Upper H-R Diagram Hints at Missing Supernova Progenitors
Dorn-Wallenstein, Trevor Z.; Levesque, Emily M.; Neugent, Kathryn F.
Characterizing the physical properties of cool supergiants allows us to probe the final stages of a massive star's evolution before it undergoes core collapse. Despite their importance, the fundamental properties of these stars- $\mathrm{log}{T}_{\mathrm{eff}}$ and $\mathrm{log}L/{L}_{\odot }$ -are only known for a limited number of objects. The t…
The first look at narrow-line Seyfert 1 galaxies with eROSITA
Salvato, M.; Buchner, J.; Boller, Th. +6 more
We present the first look at the spectral and timing analysis of narrow-line Seyfert 1 galaxies (NLS1s) with the extended ROentgen Survey with an Imaging Telescope Array (eROSITA) on board the Spectrum-Roentgen-Gamma (SRG) mission. The sample of approximately 1200 NLS1s was obtained via a cross-match between the first eROSITA All-Sky Survey (eRASS…
V445 Puppis: Dustier than a Thousand Novae
Evans, A.; Banerjee, D. P. K.; Starrfield, S. +4 more
V445 Puppis, the only known Galactic helium nova, is a unique test bed to verify supernova (SN) theories in the single-degenerate channel that involve a white dwarf (WD) accreting matter from a helium-rich donor. An estimate of the mass of the helium shell on the WD is crucial to deciding whether or not it will undergo an SN detonation. In this co…
Probing Ganymede's Atmosphere with HST Lyα Images in Transit of Jupiter
Saur, Joachim; Roth, Lorenz; Becker, Tracy M. +6 more
We report results from far-ultraviolet observations by the Hubble Space Telescope of Jupiter's largest moon, Ganymede, transiting across the planet's dayside hemisphere. Within a targeted campaign on 2021 September 9 two exposures were taken during one transit passage to probe for attenuation of Jupiter's hydrogen Lyα dayglow above the moon limb. …
The SOFIA FEEDBACK [CII] Legacy Survey: Rapid molecular cloud dispersal in RCW 79
Schneider, N.; Zavagno, A.; Tielens, A. G. G. M. +12 more
It has long been discussed whether stellar feedback in the form of winds and/or radiation can shred the nascent molecular cloud, thereby controlling the star formation rate. However, directly probing and quantifying the impact of stellar feedback on the neutral gas of the nascent clouds is challenging. We present an investigation of this impact to…
A mid-infrared study of synthetic glass and crystal mixtures analog to the geochemical terranes on mercury
Helbert, Joern; Hiesinger, Harald; Weber, Iris +8 more
The MERTIS (MErcury Radiometer and Thermal Infrared Spectrometer) onboard of the BepiColombo ESA/JAXA mission to Mercury will map the surface of Mercury in the wavelength range of 7-14 µm and for the interpretation of these spectra a database of analog materials is needed. We analyzed bulk grain size fractions of a series of analog materials…
The Lyα Reference Sample. XIV. Lyα Imaging of 45 Low-redshift Star-forming Galaxies and Inferences on Global Emission
Verhamme, Anne; Cannon, John M.; Hayes, Matthew +18 more
We present Lyα imaging of 45 low-redshift star-forming galaxies observed with the Hubble Space Telescope. The galaxies have been selected to have moderate to high star formation rates (SFRs) using far-ultraviolet (FUV) luminosity and Hα equivalent width criteria, but no constraints on Lyα luminosity. We employ a pixel stellar continuum fitting cod…
Recurrent solar density transients in the slow wind observed with the Metis coronagraph
Heinzel, P.; Sasso, C.; Romoli, M. +22 more
Aims We aim to investigate and characterize the morphology and dynamics of small-scale coronal plasma density inhomogeneities detected as brighter, denser features propagating outward through the solar corona in the visible-light images of the Metis coronagraph on board Solar Orbiter on February 22, 2021. Our main focus is on investigating their p…