Search Publications
Modeling the kinematics of globular cluster systems
Chen, Yingtian; Gnedin, Oleg Y.
Globular clusters (GCs) are old massive star clusters that serve as 'fossils' of galaxy formation. The advent of Gaia observatory has enabled detailed kinematics studies of the Galactic GCs and revolutionized our understanding of the connections between GC properties and galaxy assembly. However, lack of kinematic measurements of extragalactic GCs…
Found: a rapidly spinning white dwarf in LAMOST J024048.51+195226.9.
Dhillon, V. S.; Breedt, E.; Marsh, T. R. +9 more
We present optical photometry of the cataclysmic variable LAMOST J024048.51+195226.9 taken with the high-speed, five-band CCD camera HiPERCAM on the 10.4 m Gran Telescopio Canarias (GTC). We detect pulsations originating from the spin of its white dwarf, finding a spin period of 24.9328(38)s. The pulse amplitude is of the order of 0.2% in the g-ba…
Survey of Multiple Populations in Globular Clusters among Very-low-mass Stars
Milone, A. P.; Cordoni, G.; Marino, A. F. +14 more
Recent work has shown that near-infrared (NIR) Hubble Space Telescope (HST) photometry allows us to disentangle multiple populations (MPs) among M dwarfs of globular clusters (GCs) and to investigate this phenomenon in very-low-mass (VLM) stars. Here, we present the color-magnitude diagrams of nine GCs and the open cluster NGC 6791 in the F110W an…
Helium absorption in exoplanet atmospheres is connected to stellar coronal abundances
Poppenhaeger, K.
Transit observations in the helium triplet around 10 830 Angstrom are a successful tool to study exoplanetary atmospheres and their mass loss. Forming those lines requires ionization and recombination of helium in the exoplanetary atmosphere. This ionization is caused by stellar photons at extreme ultraviolet (EUV) wavelengths; however, no current…
The Close AGN Reference Survey (CARS). No obvious signature of AGN feedback on star formation, but subtle trends
Gaspari, M.; Klessen, R. S.; Combes, F. +17 more
Context. Active galactic nuclei (AGN) are thought to be responsible for the suppression of star formation in massive ∼1010 M⊙ galaxies. While this process is a key feature in numerical simulations of galaxy formation, it has not been unambiguously confirmed in observational studies yet.
Aims: The characterization of the …
Constraining the Nature of the 18 min Periodic Radio Transient GLEAM-X J162759.5-523504.3 via Multiwavelength Observations and Magneto-thermal Simulations
de Martino, D.; Rea, N.; Buckley, D. A. H. +14 more
We observed the periodic radio transient GLEAM-X J162759.5-523504.3 (GLEAM-X J1627) using the Chandra X-ray Observatory for about 30 ks on 2022 January 22-23, simultaneously with radio observations from the Murchison Widefield Array, MeerKAT, and the Australia Telescope Compact Array. Its radio emission and 18 min periodicity led the source to be …
The Panchromatic Hubble Andromeda Treasury: Triangulum Extended Region (PHATTER). II. The Spatially Resolved Recent Star Formation History of M33
Bell, Eric F.; Williams, Benjamin F.; Choi, Yumi +11 more
We measure the spatially resolved recent star formation history (SFH) of M33 using optical images taken with the Hubble Space Telescope as part of the Panchromatic Hubble Andromeda Treasury: Triangulum Extended Region (PHATTER) survey. The area covered by the observations used in this analysis covers a de-projected area of ~38 kpc2 and …
Spectral analysis of ultra-cool white dwarfs polluted by planetary debris
Gänsicke, Boris T.; Gentile Fusillo, Nicola Pietro; Koester, Detlev +5 more
We identify two ultra-cool (${T_\mathrm{eff}}\lt 4000$ K) metal-polluted (DZ) white dwarfs WD J2147-4035 and WD J1922+0233 as the coolest and second coolest DZ stars known to date with ${T_\mathrm{eff}}\approx 3050$ K and ${T_\mathrm{eff}}\approx 3340$ K, respectively. Strong atmospheric collision-induced absorption (CIA) causes the suppression of…
Forbidden hugs in pandemic times. III. Observations of the luminous red nova AT 2021biy in the nearby galaxy NGC 4631
Lundqvist, P.; Zheng, W.; Galbany, L. +73 more
We present an observational study of the luminous red nova (LRN) AT 2021biy in the nearby galaxy NGC 4631. The field of the object was routinely imaged during the pre-eruptive stage by synoptic surveys, but the transient was detected only at a few epochs from ∼231 days before maximum brightness. The LRN outburst was monitored with unprecedented ca…
Stellar graveyards: clustering of compact objects in globular clusters NGC 3201 and NGC 6397
Bellini, Andrea; Libralato, Mattia; Mamon, Gary A. +2 more
We analyse Gaia EDR3 and re-calibrated HST proper motion data from the core-collapsed and non-core-collapsed globular clusters NGC 6397 and NGC 3201, respectively, with the Bayesian mass-orbit modelling code MAMPOSST-PM. We use Bayesian evidence and realistic mock data sets constructed with AGAMA to select between different mass models. In both cl…