Search Publications
Distances and parallax bias in Gaia DR2
Schönrich, Ralph; Eyer, Laurent; McMillan, Paul
We derive Bayesian distances for all stars in the radial velocity sample of Gaia DR2, and use the statistical method of Schönrich, Binney & Asplund to validate the distances and test the Gaia parallaxes. In contrast to other methods, which rely on special sources, our method directly tests the distances to all stars in our sample. We find clea…
The discovery of weak coherent pulsations in the ultraluminous X-ray source NGC 1313 X-2
Fabian, A. C.; Pinto, C.; Bachetti, M. +8 more
We report the detection of weak pulsations from the archetypal ultraluminous X-ray source (ULX) NGC 1313 X-2. Acceleration searches reveal sinusoidal pulsations in segments of two out of six new deep observations of this object, with a period of ∼1.5 s and a pulsed fraction of ∼ 5 per cent. We use Monte Carlo simulations to demonstrate that the in…
Evolution of the galaxy stellar mass functions and UV luminosity functions at z = 6-9 in the Hubble Frontier Fields
Conselice, Christopher J.; Bhatawdekar, Rachana; Duncan, Kenneth +1 more
We present new measurements of the evolution of the galaxy stellar mass functions (GSMFs) and ultraviolet luminosity functions (UV LFs) for galaxies from z = 6-9 within the Frontier Field cluster MACSJ0416.1-2403 and its parallel field. To obtain these results, we derive the stellar masses of our sample by fitting synthetic stellar population mode…
A distance of 13 Mpc resolves the claimed anomalies of the galaxy lacking dark matter
Beasley, Michael A.; Borlaff, Alejandro; Vazdekis, Alexandre +10 more
The claimed detection of a diffuse galaxy lacking dark matter represents a possible challenge to our understanding of the properties of these galaxies and galaxy formation in general. The galaxy, already identified in photographic plates taken in the summer of 1976 at the UK 48-in Schmidt telescope, presents normal distance-independent properties …
On the dust temperatures of high-redshift galaxies
Faucher-Giguère, Claude-André; Hayward, Christopher C.; Hopkins, Philip F. +7 more
Dust temperature is an important property of the interstellar medium (ISM) of galaxies. It is required when converting (sub)millimetre broad-band flux to total infrared luminosity (LIR), and hence star formation rate, in high-redshift galaxies. However, different definitions of dust temperatures have been used in the literature, leading…
Is the dark-matter halo spin a predictor of galaxy spin and size?
Somerville, Rachel S.; Genel, Shy; Dekel, Avishai +8 more
The similarity between the distributions of spins for galaxies (λgal) and for dark-matter haloes (λhalo), indicated both by simulations and observations, is naively interpreted as a one-to-one correlation between the spins of a galaxy and its host halo. This is used to predict galaxy sizes in semi-analytic models via Re<…
Evidence for rapid disc formation and reprocessing in the X-ray bright tidal disruption event candidate AT 2018fyk
Gromadzki, M.; Hodgkin, S. T.; Kostrzewa-Rutkowska, Z. +15 more
We present optical spectroscopic and Swift UVOT/XRT observations of the X-ray and UV/optical bright tidal disruption event (TDE) candidate AT 2018fyk/ASASSN-18ul discovered by ASAS-SN. The Swift light curve is atypical for a TDE, entering a plateau after ∼40 d of decline from peak. After 80 d the UV/optical light curve breaks again to decline furt…
NIHAO XV: the environmental impact of the host galaxy on galactic satellite and field dwarf galaxies
Buck, Tobias; Dutton, Aaron A.; Macciò, Andrea V. +2 more
We study the impact of the host on dwarf galaxy properties using four new Milky Way (MW)-like, ultra-high-resolution simulations (Npart > 107) from the NIHAO project. We split our sample into satellite (R < R200), nearby (1 < R/R200 < 2.5), and field (R > 2.5R200) galaxies. Simu…
The total stellar halo mass of the Milky Way
Belokurov, Vasily; Sanders, Jason L.; Deason, Alis J.
We measure the total stellar halo luminosity using red giant branch (RGB) stars selected from Gaia data release 2. Using slices in magnitude, colour, and location on the sky, we decompose RGB stars belonging to the disc and halo by fitting two-dimensional Gaussians to the Galactic proper motion distributions. The number counts of RGB stars are con…
Gaia Data Release 2 distances and peculiar velocities for Galactic black hole transients
Maccarone, Thomas J.; Gandhi, Poshak; Rao, Anjali +2 more
We report on a first census of Galactic black hole X-ray binary (BHXRB) properties with the second data release (DR2) of Gaia, focusing on dynamically confirmed and strong candidate BH transients. Gaia DR2 provides five-parameter astrometric solutions including position, parallax and proper motion for 11 out of a sample of 24 systems. Distance est…