Search Publications
The progenitors of the Milky Way stellar halo: big bricks favoured over little bricks.
Belokurov, V.; Deason, A. J.; Weisz, D. R.
We present a census of blue horizontal branch (BHB) and blue straggler (BS) stars belonging to dwarf galaxies and globular clusters, and compare these counts to that of the Milky Way stellar halo. We find, in agreement with earlier studies, that the ratio of BS-to-BHB stars in these satellite populations is dependent on stellar mass. Dwarf galaxie…
Elemental Depletions in the Magellanic Clouds and the Evolution of Depletions with Metallicity
Meixner, Margaret; Seale, Jonathan; Dwek, Eli +4 more
We present a study of the composition of gas and dust in the Large and Small Magellanic Clouds (LMC and SMC) using UV absorption spectroscopy. We measure P ii and Fe ii along 84 spatially distributed sightlines toward the MCs using archival Far Ultraviolet Spectroscopic Explorer observations. For 16 of those sightlines, we also measure Si ii, Cr i…
The VLT SINFONI Mg II Program for Line Emitters (SIMPLE). II. Background Quasars Probing Z ~ 1 Galactic Winds
Finley, Hayley; Bouché, Nicolas; Contini, Thierry +3 more
The physical properties of galactic winds are of paramount importance for our understanding of galaxy formation. Fortunately, they can be constrained using background quasars passing near star-forming galaxies (SFGs). From the 14 quasar-galaxy pairs in our Very Large Telescope (VLT)/SINFONI Mg ii Program for Line Emitters sample, we reobserved the…
A survey of stellar X-ray flares from the XMM-Newton serendipitous source catalogue: HIPPARCOS-Tycho cool stars
Rosen, S.; Pye, J. P.; Schröder, A. C. +1 more
Context. The X-ray emission from flares on cool (i.e. spectral-type F-M) stars is indicative of very energetic, transient phenomena, associated with energy release via magnetic reconnection.
Aims: We present a uniform, large-scale survey of X-ray flare emission. The XMM-Newton Serendipitous Source Catalogue and its associated data products pr…
The radio relic in Abell 2256: overall spectrum and implications for electron acceleration
Lovisari, L.; Dallacasa, D.; Bonafede, A. +5 more
Context. Radio relics are extended synchrotron sources thought to be produced by shocks in the outskirts of merging galaxy clusters. The cluster Abell 2256 hosts one of the most intriguing examples in this class of sources. It has been found that this radio relic has a rather flat integrated spectrum at low frequencies that would imply an injectio…
New light on Galactic post-asymptotic giant branch stars - I. First distance catalogue
Parker, Quentin A.; Vickers, Shane B.; Frew, David J. +1 more
We have commenced a detailed analysis of the known sample of Galactic post-asymptotic giant branch (PAGB) objects compiled in the Toruń catalogue of Szczerba et al., and present, for the first time, homogeneously derived distance determinations for the 209 likely and 87 possible catalogued PAGB stars from that compilation. Knowing distances are es…
Spectroscopic Confirmation of an Ultra Massive and Compact Galaxy at z = 3.35: a Detailed Look at an Early Progenitor of Local Giant Ellipticals
van Dokkum, Pieter G.; Muzzin, Adam; Labbé, Ivo +10 more
We present the first spectroscopic confirmation of an ultramassive galaxy at redshift z\gt 3 using data from Keck-NIRSPEC, VLT-X-shooter, and GTC-Osiris. We detect strong [O iii] and Lyα emission, and weak [O ii], C iv, and He ii, placing C1-23152 at a spectroscopic redshift of {{z}spec}=3.351. The modeling of the emission-line-correcte…
Broadband Radio Polarimetry and Faraday Rotation of 563 Extragalactic Radio Sources
Gaensler, B. M.; Franzen, T. M. O.; Anderson, C. S. +1 more
We present a broadband spectropolarimetric survey of 563 discrete, mostly unresolved radio sources between 1.3 and 2.0 GHz using data taken with the Australia Telescope Compact Array. We have used rotation-measure synthesis to identify Faraday-complex polarized sources, those objects whose frequency-dependent polarization behavior indicates the pr…
Non-local gravity and comparison with observational datasets
Kunz, Martin; Pettorino, Valeria; Dirian, Yves +2 more
We study the cosmological predictions of two recently proposed non-local modifications of General Relativity. Both models have the same number of parameters as ΛCDM, with a mass parameter m replacing the cosmological constant. We implement the cosmological perturbations of the non-local models into a modification of the CLASS Boltzmann code, and w…
HST Rotational Spectral Mapping of Two L-type Brown Dwarfs: Variability in and out of Water Bands indicates High-altitude Haze Layers
Metchev, Stanimir; Showman, Adam P.; Apai, Dániel +13 more
We present time-resolved near-infrared spectroscopy of two L5 dwarfs, 2MASS J18212815+1414010 and 2MASS J15074759-1627386, observed with the Wide Field Camera 3 instrument on the Hubble Space Telescope (HST). We study the wavelength dependence of rotation-modulated flux variations between 1.1 µm and 1.7 µm. We find that the water absor…