Search Publications
Probable dormant neutron star in a short-period binary system
Maoz, Dan; Latham, David W.; Liu, Jifeng +24 more
We have identified 2XMM J125556.57+565846.4, at a distance of 600 pc, as a binary system consisting of a normal star and a probable dormant neutron star. Optical spectra exhibit a slightly evolved F-type single star, displaying periodic Doppler shifts with a 2.76-d Keplerian circular orbit, with no indication of light from a secondary component. O…
Pulsating B stars in the Scorpius-Centaurus Association with TESS
Bedding, Timothy R.; White, Timothy R.; Saio, Hideyuki +1 more
We study 119 B stars located in the Scorpius-Centaurus Association using data from NASA's TESS Mission. We see pulsations in 81 stars (68 per cent) across the full range of effective temperatures. In particular, we confirm previous reports of low-frequency pulsations in stars whose temperatures fall between the instability strips of SPB stars (slo…
An extended stellar halo discovered in the Fornax dwarf spheroidal using Gaia EDR3
Hammer, François; Pawlowski, Marcel S.; Yang, Yanbin +1 more
We have studied the extent of the Red Giant Branch stellar population in the Fornax dwarf spheroidal galaxy using the spatially extended and homogeneous data set from Gaia EDR3. Our pre-selection of stars belonging to Fornax is based on their proper motions, parallaxes, and colour-magnitude diagram. The latter criteria provide a Fornax star sample…
High-density disc reflection spectroscopy of low-mass active galactic nuclei
Fabian, A. C.; Pinto, C.; Gandhi, P. +13 more
The standard alpha-disc model predicts an anticorrelation between the density of the inner accretion disc and the black hole mass times square of the accretion rate, as seen in higher mass (MBH > 106 M⊙) active galactic nuclei (AGNs). In this work, we test the predictions of the alpha-disc model and study the pr…
The Fundamental Planes of black hole activity for radio-loud and radio-quiet quasars
Snios, Bradford; Siemiginowska, Aneta; Schwartz, Daniel A. +2 more
We examine the Fundamental Plane of black hole activity for correlations with redshift and radio loudness in both radio-loud and radio-quiet quasar populations. Sources are compiled from archival data of both radio-loud and radio-quiet quasars over redshifts 0.1 < z < 5.0 to produce a sample of 353 sources with known X-ray, radio, and black …
Haro 11 - Untying the knots of the nuclear starburst
Östlin, G.; Hayes, M.; Smith, L. J. +7 more
Star formation is a clustered process that regulates the structure and evolution of galaxies. We investigate this process in the dwarf galaxy Haro 11, forming stars in three knots (A, B, and C). The exquisite resolution of HST imaging allows us to resolve the starburst into tens of bright star clusters. We derive masses between 105 and …
UV to submillimetre luminosity functions of TNG50 galaxies
Vogelsberger, Mark; Pillepich, Annalisa; Nelson, Dylan +7 more
We apply the radiative transfer (RT) code SKIRT on a sample of ${\sim } 14\, 000$ low-redshift (z ≤ 0.1) galaxies extracted from the TNG50 simulation to enable an apples-to-apples comparison with observations. The RT procedure is calibrated via comparison of a subsample of TNG50 galaxies with the DustPedia observational sample: we compare several …
The X-ray emission of Be+stripped star binaries★
Smith, Myron A.; Nazé, Yaël; Rauw, Gregor +1 more
Using observations from Chandra, Swift, and XMM-Newton, we investigate the high-energy properties of all known (18) Be+sdO systems as well as seven additional Be binaries suspected to harbour stripped stars. The observed X-ray properties are found to be similar to those observed for other Be samples. The vast majority of these systems (15 out of 2…
The physical origin for spatially large scatter of IGM opacity at the end of reionization: The IGM Lyα opacity-galaxy density relation
Cai, Zheng; Kashino, Daichi; Onoue, Masafusa +9 more
The large opacity fluctuations in the z > 5.5 Lyα forest may indicate inhomogeneous progress of reionization. To explain the observed large scatter of the effective Lyα optical depth (τeff) of the intergalactic medium (IGM), fluctuation of UV background (Γ model), or the IGM gas temperature (T model) have been proposed, which predict…
Lack of other molecules in CO-rich debris discs: is it primordial or secondary gas?
Henning, Thomas; Hughes, A. Meredith; Moór, Attila +5 more
The nature of the gas in CO-rich debris discs remains poorly understood, as it could either be a remnant from the earlier Class II phase or of secondary origin, driven by the destruction of icy planetesimals. The aim of this paper was to elucidate the origin of the gas content in the debris discs via various simple molecules that are often detecte…