Search Publications
Serendipitous discovery of a faint dwarf galaxy near a Local Volume dwarf
Karachentsev, I. D.; Makarova, L. N.; Tully, R. B. +2 more
A faint dwarf irregular galaxy has been discovered in the HST/ACS field of LV J1157+5638. The galaxy is resolved into individual stars, including the brightest magnitude of the red giant branch. The dwarf is very likely a physical satellite of LV J1157+5638. The distance modulus of LV J1157+5638 using the tip of the red giant branch (TRGB) distanc…
The evolution of X-ray bursts in the `Bursting Pulsar' GRO J1744-28
Court, J. M. C.; Altamirano, D.; Albayati, A. C. +8 more
GRO J1744-28, commonly known as the `Bursting Pulsar', is a low-mass X-ray binary containing a neutron star and an evolved giant star. This system, together with the Rapid Burster (MXB 1730-33), are the only two systems that display the so-called type II X-ray bursts. These types of bursts, which last for tens of seconds, are thought to be caused …
Accurate radial velocity and metallicity of the Large Magellanic Cloud old globular clusters NGC 1928 and NGC 1939
Cole, A. A.; Hwang, N.; Angelo, M. S. +2 more
We present results obtained from spectroscopic observations of red giants located in the fields of the Large Magellanic Cloud (LMC) globular clusters (GCs) NGC 1928 and NGC 1939. We used the GMOS and AAOmega+2dF spectrographs to obtain spectra centred on the Ca II triplet, from which we derived individual radial velocities (RVs) and metallicities.…
The oxygen isotopic composition (18O/16O) in the dust of comet 67P/Churyumov-Gerasimenko measured by COSIMA on-board Rosetta
Hilchenbach, M.; Engrand, C.; Kissel, J. +5 more
The oxygen isotopic ratio 18O/16O has been measured in cometary gas for a wide variety of comets, but the only measurements in cometary dust were performed by the Stardust cometary sample return mission. Most such measurements find a value of the ratio that is consistent with Vienna Standard Mean Ocean Water (VSMOW) within er…
XMM-Newton observations of the Southeastern radio relic in Abell 3667
Vink, Jacco; Akamatsu, Hiroki; Storm, Emma +1 more
Radio relics, elongated, non-thermal, structures located at the edges of galaxy clusters, are the result of synchrotron radiation from cosmic ray electrons accelerated by merger-driven shocks at the cluster outskirts. However, X-ray observations of such shocks in some clusters suggest that they are too weak to efficiently accelerate electrons via …
Atmospheric mass-loss of extrasolar planets orbiting magnetically active host stars
Schmitt, J. H. M. M.; Lalitha, Sairam; Dash, Spandan
Magnetic stellar activity of exoplanet hosts can lead to the production of large amounts of high-energy emission, which irradiates extrasolar planets, located in the immediate vicinity of such stars. This radiation is absorbed in the planets' upper atmospheres, which consequently heat up and evaporate, possibly leading to an irradiation-induced ma…
Dependence of galaxy clustering on UV luminosity and stellar mass at z ∼ 4-7
Illingworth, Garth D.; Labbé, Ivo; Bouwens, Rychard J. +6 more
We investigate the dependence of galaxy clustering at z ∼ 4-7 on UV luminosity and stellar mass. Our sample consists of ∼10 000 Lyman-break galaxies in the eXtreme Deep Field (XDF) and Cosmic Assembly Near-infrared Deep Extragalatic Legacy Survey (CANDELS) fields. As part of our analysis, the M⋆-MUV relation is estimated for …
CLUES about M33: the reversed radial stellar age gradient in the outskirts of Triangulum galaxy
Minchev, Ivan; Libeskind, Noam I.; Knebe, Alexander +3 more
HST/ACS observations along the major axis of M33 show that the mean age of its stars decreases with increasing distance from the galaxy centre. Such a behaviour is consistent with an inside-out growth of the disc. However, in the outermost observed field, at r ≃ 11.6 kpc, a reversal of this gradient is detected, with old stars found in high percen…
Spatially associated clump populations in Rosette from CO and dust maps
Klessen, Ralf S.; Ossenkopf-Okada, Volker; Schneider, Nicola +3 more
Spatial association of clumps from different tracers turns out to be a valuable tool to determine the physical properties of molecular clouds. It provides a reliable estimate for the X-factors, serves to trace the density of clumps seen in column densities only, and allows one to measure the velocity dispersion of clumps identified in dust emissio…
Improved mass constraints for two nearby strong-lensing elliptical galaxies from Hubble Space Telescope imaging
Lucey, John R.; Smith, Russell J.; Collier, William P.
We analyse newly obtained Hubble Space Telescope imaging for two nearby strong lensing elliptical galaxies, SNL-1 (z = 0.03) and SNL-2 (z = 0.05), in order to improve the lensing mass constraints. The imaging reveals previously unseen structure in both the lens galaxies and lensed images. For SNL-1, which has a well resolved source, we break the m…