Search Publications

Erratum: XMM-Newton large program on SN1006 - I. Methods and initial results of spatially resolved spectroscopy

Vink, Jacco; Miceli, Marco; Bocchino, Fabrizio +2 more

A multiwavelength view of the open cluster NGC 2527: discovery of active stars

Singh, K. P.; Shah, Nevil; Subramaniam, Annapurni

Star clusters are ideal platforms for categorizing X-ray emitting stars and to study X-ray emission as a function of stellar age and activity. We present a comprehensive study of an open star cluster, NGC 2527, by combining data from XMM-UVOT-Gaia. Cluster membership of stars and their photometry are taken from Gaia and cross-matched with XMM and …

Pinnacles on the surface of the comet 67P/Churyumov-Gerasimenko: regional distribution and morphology

Keller, H. U.; Hviid, S. F.; Mall, U. +3 more

Pinnacles are local topographic promontories of different shapes considered to be formed due to uneven surface erosion. In the case of comets, areal changes in the degree of erosion could be related to inhomogeneities of the nucleus. However, the amount of the solar radiation and the thermal gradient is different across the orbit for geomorphologi…

UNIVERSEMACHINE: The correlation between galaxy growth and dark matter halo assembly from z = 0-10

Conroy, Charlie; Behroozi, Peter; Wechsler, Risa H. +1 more

We present a method to flexibly and self-consistently determine individual galaxies' star formation rates (SFRs) from their host haloes' potential well depths, assembly histories, and redshifts. The method is constrained by galaxies' observed stellar mass functions, SFRs (specific and cosmic), quenched fractions, ultraviolet (UV) luminosity functi…

SIMBA: Cosmological simulations with black hole growth and feedback

Davé, Romeel; Narayanan, Desika; Li, Qi +3 more

We introduce the SIMBA simulations, the next generation of the MUFASA cosmological galaxy formation simulations run with GIZMO's meshless finite mass hydrodynamics. SIMBA includes updates to MUFASA's sub-resolution star formation and feedback prescriptions, and introduces black hole growth via the torque-limited accretion model of Anglés-Alcázar e…

Evidence for two early accretion events that built the Milky Way stellar halo

Myeong, G. C.; Evans, N. W.; Belokurov, V. +2 more

The Gaia Sausage is the major accretion event that built the stellar halo of the Milky Way galaxy. Here, we provide dynamical and chemical evidence for a second substantial accretion episode, distinct from the Gaia Sausage. The Sequoia Event provided the bulk of the high-energy retrograde stars in the stellar halo, as well as the recently discover…

Mean proper motions, space orbits, and velocity dispersion profiles of Galactic globular clusters derived from Gaia DR2 data

Hilker, M.; Bellini, A.; Baumgardt, H. +1 more

We have derived the mean proper motions and space velocities of 154 Galactic globular clusters and the velocity dispersion profiles of 141 globular clusters based on a combination of Gaia DR2 proper motions with ground-based line-of-sight velocities. Combining the velocity dispersion profiles derived here with new measurements of the internal mass…

A Gaia Data Release 2 catalogue of white dwarfs and a comparison with SDSS

Toonen, Silvia; Hollands, Mark; Raddi, Roberto +11 more

We present a catalogue of white dwarf candidates selected from the second data release of Gaia (DR2). We used a sample of spectroscopically confirmed white dwarfs from the Sloan Digital Sky Survey (SDSS) to map the entire space spanned by these objects in the Gaia Hertzsprung-Russell diagram. We then defined a set of cuts in absolute magnitude, co…

The formation and assembly history of the Milky Way revealed by its globular cluster population

Kruijssen, J. M. Diederik; Crain, Robert A.; Bastian, Nate +2 more

We use the age-metallicity distribution of 96 Galactic globular clusters (GCs) to infer the formation and assembly history of the Milky Way (MW), culminating in the reconstruction of its merger tree. Based on a quantitative comparison of the Galactic GC population to the 25 cosmological zoom-in simulations of MW-mass galaxies in the E-MOSAICS proj…

H0LiCOW - IX. Cosmographic analysis of the doubly imaged quasar SDSS 1206+4332 and a new measurement of the Hubble constant

Treu, T.; Fassnacht, C. D.; Meylan, G. +15 more

We present a blind time-delay strong lensing (TDSL) cosmographic analysis of the doubly imaged quasar SDSS 1206+4332 . We combine the relative time delay between the quasar images, Hubble Space Telescope imaging, the Keck stellar velocity dispersion of the lensing galaxy, and wide-field photometric and spectroscopic data of the field to constrain …