Search Publications
Localizing short-period pulsations in hard X-rays and γ-rays during an X9.0 flare
Li, Dong
Context. The feature of quasi-periodic pulsations (QPPs) is frequently observed in the light curve of solar and stellar flares. However, the short-period QPP is rarely reported in the high energy range of hard X-rays (HXRs) and γ-rays. Aims. We investigated the QPP at a shorter period of about 1 s in high-energy channels of HXRs and γ-ray continuu…
The cosmological analysis of X-ray cluster surveys: VI. Inference based on analytically simulated observable diagrams
Pierre, M.; Werner, N.; Kosiba, M. +4 more
Context. The number density of galaxy clusters across mass and redshift has been established as a powerful cosmological probe, yielding important information on the matter components of the Universe. Cosmological analyses with galaxy clusters traditionally employ scaling relations, which are empirical relationships between cluster masses and their…
A study of the frequency and characteristics of stellar companions and Jupiter-like planets in nearby open clusters
Barbato, D.; D'Orazi, V.; Nascimbeni, V. +9 more
Context. Observations of companions of solar-type stars in nearby young moving groups (NYMGs) show that they split into two groups: stellar and brown dwarf companions (mass ratio q > 0.05) and Jupiter-like (JL) planets (q < 0.02). The frequency of JL planets in NYMGs appears to be higher than that obtained from radial velocity (RV) surveys. …
Behind the dust veil: A panchromatic view of an optically dark galaxy at z = 4.82
Koekemoer, Anton M.; Daddi, Emanuele; Schinnerer, Eva +30 more
Optically dark dusty star-forming galaxies (DSFGs) play an essential role in massive galaxy formation at early cosmic time; however, their nature remains elusive. Here, we present a detailed case study of all the baryonic components of a z = 4.821 DSFG, XS55. Selected from the ultra-deep COSMOS-XS 3 GHz map with a red SCUBA-2 450 µm/850 &mic…
Unveiling the binary nature of NGC 2323
Wang, Long; Chen, Li; Zhong, Jing +9 more
Context. As a well-known open cluster, NGC 2323 (also called M50) has been widely investigated for over a hundred years and has always been considered a classical single cluster. Aims. We studied the binary structure nature of NGC 2323 with Gaia Data Release 3 (DR3). Methods. We discovered the binary structure of NGC 2323 by the HDBSCAN algorithm …
IXPE observation of the low-synchrotron peaked blazar S4 0954+65 during an optical-X-ray flare
Kaaret, Philip; Wu, Kinwah; Enoto, Teruaki +135 more
The X-ray polarization observations, made possible with the Imaging X-ray Polarimetry Explorer (IXPE), offer new ways of probing high-energy emission processes in astrophysical jets from blazars. Here, we report the first X-ray polarization observation of the blazar S4 0954+65 in a high optical and X-ray state. During our multi-wavelength (MWL) ca…
The TW Hydrae Association is a cluster chain of Sco-Cen
Miret-Roig, N.; Bouy, H.; Figueras, F. +9 more
The TW Hydrae Association (TWA) is a young local association (YLA) about 50 pc from the Sun, offering a unique opportunity to study star and planet formation processes in detail. We characterized TWA's location, kinematics, and age, investigating its origin within the Scorpius-Centaurus (Sco-Cen) OB association. Using Gaia DR3 astrometric data and…
Spherical bias in the 3D reconstruction of the ICM density profile in galaxy clusters
Rossetti, M.; Veronesi, I.; Bartalucci, I. +9 more
Context. X-ray observations of galaxy clusters are routinely used to derive radial distributions of intracluster medium (ICM) thermodynamical properties, such as density and temperature. However, observations only allow access to quantities projected on the celestial sphere, so an assumption on the three-dimensional distribution of the ICM is nece…
The lithium-rich giant stars puzzle: New observational trends for a general-mass-loss scenario
de la Reza, R.
The existence of one percent of lithium-rich giant stars among normal, lithium-poor giant stars continues to be poorly explained. By merging two catalogues – one containing 10,535 lithium-rich giant stars with lithium abundances ranging from 1.5 to 4.9 dex, and the other detecting infrared sources – we have found 421 clump giant stars and 196 firs…
The 3D morphology of open clusters in the solar neighborhood: III. Fractal dimension of open clusters
Vallenari, A.; Kouwenhoven, M. B. N.; Pasquato, M. +2 more
We analyzed the fractal dimension of open clusters using 3D spatial data from Gaia DR 3 for 93 open clusters from Pang et al. and 127 open clusters from Hunt & Reffert mainly within 500 pc. The box-counting method was adopted to calculate the fractal dimension of each cluster in three regions: the all-member region, r ≤ rt (inside t…