Ralf Kotulla

TL;DR: The GALEV (Galev Evolutionary Evolutionary Models for Galaxies) model as mentioned in this paper describes the evolution of stellar populations in general, of star clusters as well as of galaxies, both in terms of resolved stellar populations and of integrated light properties over cosmological time-scales of ≥13 Gyr.

TL;DR: The PHoto-z Accuracy Testing Program (PHAT) as mentioned in this paper is an international initiative to test and compare different methods of photo-z estimation, and the test data sets are publicly available and can be used to compare new, upcoming methods to established ones and help in guiding future photoz method development.

TL;DR: In this article, the authors present observations of the interstellar interloper 1I/2017 U1 ('Oumuamua') taken during its 2017 October flyby of Earth.

TL;DR: In this paper, the authors examined the star formation in the outer halo of NGC 1275, the central galaxy in the Perseus cluster (Abell 426), using far ultraviolet and optical images obtained with the Hubble Space Telescope.

TL;DR: In this article, the authors presented the detection of 89 low surface brightness (LSB) and thus low stellar density galaxy candidates in the Perseus cluster core, of the kind named "ultra-diffuse galaxies" with mean effective V-band surface brightnesses 248-271 mag arcsec−2, total V-bands magnitudes −118 to −155 mag, and half-light radii 07-41 kpc.