Search Publications
The Ly α, C IV, and He II nebulae around J1000+0234: a galaxy pair at the centre of a galaxy overdensity at z = 4.5
Magnelli, B.; Smolčić, V.; Gómez-Guijarro, C. +7 more
Ly α λ1216 (Ly α) emission extending over $\gtrsim \, \rm 10\, kilo\,parsec\, (kpc)$ around dusty, massive starbursts at z ≳ 3 might represent a short-lived phase in the evolution of present-day, massive quiescent galaxies. To obtain empirical constraints on this emerging scenario, we present Ly α, C IVλ1550 (C IV), and He II λ1640 (He II) observa…
Peekaboo: the extremely metal poor dwarf galaxy HIPASS J1131-31
Koribalski, B. S.; Karachentsev, I. D.; Anand, G. S. +3 more
The dwarf irregular galaxy HIPASS J1131-31 was discovered as a source of HI emission at low redshift in such close proximity of a bright star that we call it Peekaboo. The galaxy resolves into stars in images with Hubble Space Telescope, leading to a distance estimate of 6.8 ± 0.7 Mpc. Spectral optical observations with the Southern African Large …
Ultracool dwarfs candidates based on 6 yr of the Dark Energy Survey data
Bacon, D.; Bechtol, K.; Smith, M. +58 more
We present a sample of 19 583 ultracool dwarf candidates brighter than z ≤23 selected from the Dark Energy Survey DR2 coadd data matched to VHS DR6, VIKING DR5, and AllWISE covering ~ 480 deg2. The ultracool candidates were first pre-selected based on their (i-z), (z-Y), and (Y-J) colours. They were further classified using a method tha…
Modelling uncertainties in wide binary constraints on primordial black holes
Goodwin, Simon P.; Green, Anne M.; Tyler, Emily
Dark matter in the form of compact objects with mass Mco ≳ 10 M⊙ can be constrained by its dynamical effects on wide binary stars. Motivated by the recent interest in primordial black hole dark matter, we revisit the theoretical modelling involved in these constraints. We improve on previous studies in several ways. Specifica…
Two substellar survivor candidates: one found and one missing
Hermes, J. J.; von Hippel, T.; Breedt, E. +4 more
This study presents observations of two possible substellar survivors of post-main sequence engulfment, currently orbiting white dwarf stars. Infrared and optical spectroscopy of GD 1400 reveals a 9.98 h orbital period, where the benchmark brown dwarf has M2 = 68 ± 8 MJup, Teff ≈ 2100 K, and a cooling age under 1 G…
The SkyMapper search for extremely metal-poor stars in the Large Magellanic Cloud
Da Costa, G. S.; Mackey, A. D.; Nordlander, T. +2 more
We present results of a search for extremely metal-poor stars in the Large Magellanic Cloud (LMC), which can provide crucial information about the properties of the first stars as well as on the formation conditions prevalent during the earliest stages of star formation in dwarf galaxies. Our search utilized SkyMapper photometry, together with par…
Extreme mass ratios and fast rotation in three massive binaries
Nazé, Yaël; Labadie-Bartz, Jonathan; Rauw, Gregor +2 more
The origin of rapid rotation in massive stars remains debated, although binary interactions are now often advocated as a cause. However, the broad and shallow lines in the spectra of fast rotators make direct detection of binarity difficult. In this paper, we report on the discovery and analysis of multiplicity for three fast-rotating massive star…
First observational evidence of a relation between globular clusters' internal rotation and stellar masses
Bedin, L. R.; Vesperini, E.; Bellini, A. +3 more
Several observational studies have shown that many Galactic globular clusters (GCs) are characterized by internal rotation. Theoretical studies of the dynamical evolution of rotating clusters have predicted that, during their long-term evolution, these stellar systems should develop a dependence of the rotational velocity around the cluster's cent…
Detecting planetary mass companions near the water frost-line using JWST interferometry
Carter, Aarynn L.; Hinkley, Sasha; Sallum, Steph +4 more
JWST promises to be the most versatile infrared observatory for the next two decades. The Near Infrared and Slitless Spectrograph (NIRISS) instrument, when used in the Aperture Masking Interferometry (AMI) mode, will provide an unparalleled combination of angular resolution and sensitivity compared to any existing observatory at mid-infrared wavel…
Determining satellite infall times using machine learning
Cautun, Marius; Barmentloo, Stan
A key unknown of the Milky Way (MW) satellites is their orbital history, and, in particular, the time they were accreted onto the MW system since it marks the point where they experience a multitude of environmental processes. We present a new methodology for determining infall times, namely using a neural network (NN) algorithm. The NN is trained…