Search Publications
The rapidly spinning intermediate-mass black hole 3XMM J150052.0+015452
Jonker, P. G.; Zabludoff, A. I.; Stone, N. C. +2 more
A star tidally disrupted by a black hole can form an accretion disc with a super-Eddington mass accretion rate; the X-ray emission produced by the inner disc provides constraints on the black hole mass M• and dimensionless spin parameter a•. Previous studies have suggested that the M• responsible for the tidal disr…
Stellar-mass black holes in the Hyades star cluster?
Wang, L.; Anders, F.; Gieles, M. +3 more
Astrophysical models of binary-black hole mergers in the universe require a significant fraction of stellar-mass black holes (BHs) to receive negligible natal kicks to explain the gravitational wave detections. This implies that BHs should be retained even in open clusters with low escape velocities (≲1 km s-1). We search for signatures…
Searching for the extra-tidal stars of globular clusters using high-dimensional analysis and a core particle spray code
Speagle, Joshua S.; Webb, Jeremy J.; Leigh, Nathan W. C. +2 more
Three-body interactions can eject stars from the core of a globular cluster, causing them to enter the Galactic halo as extra-tidal stars. While finding extra-tidal stars is imperative for understanding cluster evolution, connecting isolated extra-tidal field stars back to their birth cluster is extremely difficult. In this work, we present a new …
The shared evaporation history of three sub-Neptunes spanning the radius-period valley of a hyades star
Fernández Fernández, Jorge; Wheatley, Peter J.; King, George W.
We model the evaporation histories of the three planets around K2-136, a K-dwarf in the Hyades open cluster with an age of 700 Myr. The star hosts three transiting planets, with radii of 1.0, 3.0, and 1.5 Earth radii, where the middle planet lies above the radius-period valley and the inner and outer planets are below. We use an XMM-Newton observa…
The X-ray view of optically selected dual AGN
Komossa, S.; Guainazzi, Matteo; Paragi, Zsolt +12 more
We present a study of optically selected dual Active Galactic Nuclei (AGN) with projected separations of 3-97 kpc. Using multiwavelength (MWL) information (optical, X-ray, mid-IR), we characterized the intrinsic nuclear properties of this sample and compared them with those of isolated systems. Among the 124 X-ray-detected AGN candidates, 52 appea…
Deep drilling in the time domain with DECam: survey characterization
Clarkson, William I.; Lee, Chien-Hsiu; Rest, Armin +41 more
This paper presents a new optical imaging survey of four deep drilling fields (DDFs), two Galactic and two extragalactic, with the Dark Energy Camera (DECam) on the 4-m Blanco telescope at the Cerro Tololo Inter-American Observatory (CTIO). During the first year of observations in 2021, >4000 images covering 21 deg2 (seven DECam poin…
An elusive dark central mass in the globular cluster M4
Anderson, Jay; Bedin, Luigi R.; Bellini, Andrea +4 more
Recent studies of nearby globular clusters have discovered excess dark mass in their cores, apparently in an extended distribution, and simulations indicate that this mass is composed mostly of white dwarfs (respectively stellar-mass black holes) in clusters that are core collapsed (respectively with a flatter core). We perform mass-anisotropy mod…
Stable accretion in young stars: the cases of EX Lupi and TW Hya
Ábrahám, P.; Kóspál, Á.; Scholz, A. +8 more
We examine the long-term spectroscopic and photometric variability of EX Lupi and TW Hya, studying the presence of stable accretion and the role it plays in the observed variability. Analysing the velocity modulations of the emission lines with STAR-MELT, we obtain information on the structure of the accretion columns and the disc-star connection.…
The EBLM project - IX. Five fully convective M-dwarfs, precisely measured with CHEOPS and TESS light curves
Alonso, R.; Deleuil, M.; Erikson, A. +85 more
Eclipsing binaries are important benchmark objects to test and calibrate stellar structure and evolution models. This is especially true for binaries with a fully convective M-dwarf component for which direct measurements of these stars' masses and radii are difficult using other techniques. Within the potential of M-dwarfs to be exoplanet host st…
A kinematic calibration of the O-rich Mira variable period-age relation from Gaia
Zhang, Hanyuan; Sanders, Jason L.
Empirical and theoretical studies have demonstrated that the periods of Mira variable stars are related to their ages. This, together with their brightness in the infrared, makes them powerful probes of the formation and evolution of highly-extincted or distant parts of the Local Group. Here we utilize the Gaia DR3 catalogue of long-period variabl…