Search Publications
First constraints on the AGN X-ray luminosity function at z 6 from an eROSITA-detected quasar
Georgakakis, A.; Salvato, M.; Buchner, J. +19 more
Context. High-redshift quasars signpost the early accretion history of the Universe. The penetrating nature of X-rays enables a less absorption-biased census of the population of these luminous and persistent sources compared to optical/near-infrared colour selection. The ongoing SRG/eROSITA X-ray all-sky survey offers a unique opportunity to unco…
Primordial black holes and secondary gravitational waves from string inspired general no-scale supergravity
Gong, Yungui; Wu, Lina; Li, Tianjun
The formation of primordial black hole (PBH) dark matter and the generation of scalar induced secondary gravitational waves (SIGWs) have been studied in the generic no-scale supergravity inflationary models. By adding an exponential term to the Kähler potential, the inflaton experiences a period of ultraslow-roll and the amplitude of primordial po…
UV line-driven disc wind as the origin of UltraFast Outflows in AGN
Done, Chris; Mizumoto, Misaki; Odaka, Hirokazu +2 more
UltraFast Outflows (UFOs) are observed in some active galactic nuclei (AGN), with blueshifted and highly ionized Fe-K absorption features. AGN typically have an ultraviolet (UV-) bright accretion flow, so UV line driving is an obvious candidate for launching these winds. However this mechanism requires material with UV opacity, in apparent conflic…
Dark matter properties through cosmic history
Kopp, Michael; Skordis, Constantinos; Thomas, Daniel B. +1 more
We perform the first test of dark matter (DM) stress-energy evolution through cosmic history, using cosmic microwave background measurements supplemented with baryon acoustic oscillation data and the Hubble Space Telescope key project data. We constrain the DM equation of state (EoS) in 8 redshift bins, and its sound speed and (shear) viscosity in…
A β Cephei pulsator and a changing orbital inclination in the high-mass eclipsing binary system VV Orionis
Bowman, D. M.; Southworth, John; Pavlovski, K.
We present an analysis of the high-mass eclipsing binary system VV Ori based on photometry from the TESS satellite. The primary star (B1 V, 9.5 $\, {\rm M}_\odot$) shows β Cephei pulsations and the secondary (B7 V, 3.8 $\, {\rm M}_\odot$) is possibly a slowly pulsating B star. We detect 51 significant oscillation frequencies, including two multipl…
Reconstructing the Extreme Ultraviolet Emission of Cool Dwarfs Using Differential Emission Measure Polynomials
Loyd, R. O. Parke; Kowalski, Adam F.; Redfield, Seth +16 more
Characterizing the atmospheres of planets orbiting M dwarfs requires understanding the spectral energy distributions of M dwarfs over planetary lifetimes. Surveys like MUSCLES, HAZMAT, and FUMES have collected multiwavelength spectra across the spectral type's range of Teff and activity, but the extreme ultraviolet (EUV, 100-912 Å) flux…
The bursty star formation history of the Fornax dwarf spheroidal galaxy revealed with the HST
Monelli, M.; Cassisi, S.; Gallart, C. +4 more
We present a new derivation of the star formation history (SFH) of the dSph galaxy Fornax in two central regions, characterized by unprecedented precision and age resolution. It reveals that star formation has proceeded in sharp bursts separated by periods of low level or quiescent activity. The SFH was derived through colour-magnitude diagram (CM…
Search for flares and associated CMEs on late-type main-sequence stars in optical SDSS spectra
Temmer, Manuela; Veronig, Astrid; Beck, Paul G. +3 more
Aims: This work aims to detect and classify stellar flares and potential stellar coronal mass ejection (CME) signatures in optical spectra provided by the Sloan Digital Sky Survey (SDSS) data release 14. The sample is constrained to all F, G, K, and M main-sequence type stars, resulting in more than 630 000 stars. This work makes use of the i…
The Tharsis mantle source of depleted shergottites revealed by 90 million impact craters
Baratoux, D.; Towner, M. C.; Lagain, A. +8 more
The only martian rock samples on Earth are meteorites ejected from the surface of Mars by asteroid impacts. The locations and geological contexts of the launch sites are currently unknown. Determining the impact locations is essential to unravel the relations between the evolution of the martian interior and its surface. Here we adapt a Crater Det…
The MUSE-Faint survey. II. The dark-matter density profile of the ultra-faint dwarf galaxy Eridanus 2
Brinchmann, Jarle; Maseda, Michael V.; Krajnović, Davor +5 more
Aims: We use stellar line-of-sight velocities to constrain the dark-matter density profile of Eridanus 2, an ultra-faint dwarf galaxy with an absolute V-band magnitude MV = −7.1 that corresponds to a stellar mass M* ≈ 9 × 104 M⊙. We furthermore derive constraints on fundamental properties of self-in…