Astronomisches Rechen-Institut

Jan 17, 2025 | academic.oup.com | Madingley Road |Astronomisches Rechen-Institut

Carbon-rich (C-rich) stars can be found at all metallicities and evolutionary stages. They are often the result of mass-transfer from a companion, but some of the most metal-poor C-rich objects are likely carrying the imprint of the metal-free First Stars from birth. In this work, we employ a neural network to predict metallicities and carbon abundances for over 10 million stars with Gaia low-resolution XP spectra, down to and up to ⁠.

Jan 15, 2025 | academic.oup.com | Technische Universität München |Astronomisches Rechen-Institut |J Michael

GRB 200415A, a short and very bright pulse of γ-rays, has been claimed to be an extragalactic magnetar giant flare (MGF) in the galaxy NGC 253. However, as the redshift of the transient was not measured, it is possible that the measured location of the transient on the celestial sphere and the location of the local galaxy merely coincided.

Jun 17, 2024 | academic.oup.com | Academia Sinica |Astronomisches Rechen-Institut |Dipartimento di Fisica

In the galaxy, it is estimated that more than 40–50 per cent of stars are part of a binary system (Duquennoy & Mayor 1991; Raghavan et al. 2010; Tokovinin 2014a, b). Young binary star systems are commonly surrounded by a circumbinary disc of gas and dust, which are the sites for planet formation. Observations naturally reveal that circumbinary discs are commonly misaligned to the binary orbital plane (e.g. Czekala et al. 2019).

Jan 27, 2024 | academic.oup.com | Astronomisches Rechen-Institut

Globular clusters (GCs) are a powerful tool to study galaxy formation (see reviews by Brodie & Strader 2006; Forbes et al. 2018) as the properties of GCs observed today reflect not only the conditions of their formation but also the physics of GC survival.

Dec 4, 2023 | academic.oup.com | Astronomisches Rechen-Institut

A key assumption in quasar absorption line studies of the circumgalactic medium (CGM) is that each absorption component maps to a spatially isolated ‘cloud’ structure that has single valued properties (e.g. density, temperature, metallicity). We aim to assess and quantify the degree of accuracy underlying this assumption. We used adaptive mesh refinement hydrodynamic cosmological simulations of two z = 1 dwarf galaxies and generated synthetic quasar absorption-line spectra of their CGM.