Search Publications
Reading the tea leaves in the Mbh-M*,sph and Mbh-Re,sph diagrams: dry and gaseous mergers with remnant angular momentum
Graham, Alister W.; Sahu, Nandini
We recently revealed that bulges and elliptical galaxies broadly define distinct, superlinear relations in the (black hole mass, Mbh)-(spheroid stellar mass, M*,sph) diagram or Mbh-M*,sph diagram, with the order-of-magnitude lower Mbh/M*,sph ratios in the elliptical galaxies due to …
Exploring the diversity and similarity of radially anisotropic Milky Way-like stellar haloes: implications for disrupted dwarf galaxy searches
Springel, Volker; Orkney, Matthew D. A.; Laporte, Chervin F. P. +7 more
We investigate the properties of mergers comparable to the Gaia-Sausage-Enceladus (GSE) using cosmological hydrodynamical simulations of Milky Way-like galaxies. The merger progenitors span an order of magnitude in their peak stellar mass ($3\times 10^8\lt M_{\star }/\rm {M}_{\odot }\lt 4\times 10^9$) and include both rotation and pressure-support…
Two warm Neptunes transiting HIP 9618 revealed by TESS and Cheops
Guterman, P.; Alonso, R.; Deleuil, M. +126 more
HIP 9618 (HD 12572, TOI-1471, TIC 306263608) is a bright (G = 9.0 mag) solar analogue. TESS photometry revealed the star to have two candidate planets with radii of 3.9 ± 0.044 R⊕ (HIP 9618 b) and 3.343 ± 0.039 R⊕ (HIP 9618 c). While the 20.77291 d period of HIP 9618 b was measured unambiguously, HIP 9618 c showed only two tr…
Evidence for mass-dependent peculiar velocities in compact object binaries: towards better constraints on natal kicks
Maccarone, Thomas J.; Gandhi, Poshak; Zhao, Yue +4 more
We compile a catalogue of low-mass and high-mass X-ray binaries, some recently reported binaries that likely host a neutron star (NS) or a black hole (BH), and binary pulsars (a pulsar and a non-degenerated companion) that have measured systemic radial velocities (γ). Using Gaia and radio proper motions together with γ, we integrate their Galactic…
Updated radial velocities and new constraints on the nature of the unseen source in NGC1850 BH1
Usher, C.; Bastian, N.; Saracino, S. +7 more
A black hole candidate orbiting a luminous star in the Large Magellanic Cloud young cluster NGC 1850 (~100 Myr) has recently been reported based on radial velocity and light-curve modelling. Subsequently, an alternative explanation has been suggested for the system: a bloated post-mass transfer secondary star (Minitial ~ 4-5 M⊙
Planet(esimal)s around stars with TESS (PAST) III: A search for triplet He I in the atmospheres of two 200 Myr-old planets
Tamura, Motohide; Gaidos, Eric; Hirano, Teruyuki +13 more
We report a search for excess absorption in the 1083.2 nm line of ortho (triplet) helium during transits of TOI-1807b and TOI-2076b, 1.25 and 2.5-R⊕ planets on 0.55- and 10.4-d orbits around nearby ~200 Myr-old K dwarf stars. We limit the equivalent width of any transit-associated absorption to <4 and <8 mÅ, respectively. We limit…
The evolution of the Milky Way's thin disc radial metallicity gradient with K2 asteroseismic ages
Chiappini, Cristina; Mackereth, J. Ted; Miglio, Andrea +8 more
The radial metallicity distribution of the Milky Way's disc is an important observational constraint for models of the formation and evolution of our Galaxy. It informs our understanding of the chemical enrichment of the Galactic disc and the dynamical processes therein, particularly radial migration. We investigate how the metallicity changes wit…
Observational constraints on the origin of the elements - VII. NLTE analysis of Y II lines in spectra of cool stars and implications for Y as a Galactic chemical clock
Bergemann, Maria; Storm, Nicholas
Yttrium (Y), a key s-process element, is commonly used in nucleosynthesis studies and as a Galactic chemical clock when combined with magnesium (Mg). We study the applicability of the previously assumed local thermal equilibrium (LTE) line formation assumption in Y abundance studies of main-sequence and red giant stars, and probe the impact of NLT…
Dwarf galaxy archaeology from chemical abundances and star-formation histories
Conroy, Charlie; Ting, Yuan-Sen; Cargile, Phillip A. +8 more
We model the stellar abundances and ages of two disrupted dwarf galaxies in the Milky Way stellar halo: Gaia-Sausage Enceladus (GSE) and Wukong/LMS-1. Using a statistically robust likelihood function, we fit one-zone models of galactic chemical evolution with exponential infall histories to both systems, deriving e-folding time-scales of τin<…
Cataclysmic Variables from Sloan Digital Sky Survey - V. The search for period bouncers continues
Hermes, J. J.; Breedt, E.; Roman-Lopes, A. +25 more
SDSS-V is carrying out a dedicated survey for white dwarfs, single, and in binaries, and we report the analysis of the spectroscopy of 118 cataclysmic variables (CVs) and CV candidates obtained during the final plug plate observations of SDSS. We identify eight new CVs, spectroscopically confirm 53 and refute 11 published CV candidates, and we rep…