Search Publications
Generalized Rotation Curves of the Milky Way from the GAIA DR3 Data Set: Constraints on Mass Models
Sylos Labini, Francesco
The circular velocity curve traced by stars provides a direct means of investigating the potential and mass distribution of the Milky Way. Recent measurements of the Galaxy's rotation curve have revealed a significant decrease in velocity for Galactic radii larger than approximately 15 kpc. While these determinations have primarily focused on the …
The star formation history of the first bulge fossil fragment candidate Terzan 5
Dalessandro, E.; Cignoni, M.; Massari, D. +6 more
Context. Terzan 5 and Liller 1 are the only bulge stellar clusters hosting multi-iron and multi-age stellar populations. They are therefore claimed to constitute a novel class of astrophysical objects: the fossils of massive star-forming clumps that possibly sank to the center of the Milky Way and contributed to the formation of the bulge. This is…
Surface properties of the seas of Titan as revealed by Cassini mission bistatic radar experiments
Soderblom, Jason M.; Lorenz, Ralph D.; Tortora, Paolo +9 more
Saturn's moon Titan was explored by the Cassini spacecraft from 2004 to 2017. While Cassini revealed a lot about this Earth-like world, its radar observations could only provide limited information about Titan's liquid hydrocarbons seas Kraken, Ligeia and Punga Mare. Here, we show the results of the analysis of the Cassini mission bistatic radar e…
Edge-on galaxies in the HST COSMOS field: the evolution of stellar discs up to z 0.5
Usachev, Pavel A.; Reshetnikov, Vladimir P.; Savchenko, Sergey S.
We present a sample of 950 edge-on spiral galaxies found with the use of an artificial neural network in the Hubble Space Telescope COSMOS field. This is currently the largest sample of distant edge-on galaxies. For all galaxies we analysed the 2D brightness distributions in the F814W filter and measured the radial and vertical exponential scales …
Exploring the stellar rotation of early-type stars in the LAMOST medium-resolution survey: III. Evolution
Chiappini, Cristina; Sun, Weijia
Context. Stellar rotation significantly shapes the evolution of massive stars, yet the interplay of mass and metallicity remains elusive, limiting our capacity to construct accurate stellar evolution models and to better estimate the impact of rotation on the chemical evolution of galaxies. Aims. Our goal is to investigate how mass and metallicity…
Atmospheric Retrievals of the Phase-resolved Spectra of Irradiated Brown Dwarfs WD-0137B and EPIC-2122B
Lothringer, Joshua D.; Apai, Dániel; Parmentier, Vivien +3 more
We present an atmospheric retrieval analysis of Hubble Space Telescope/Wide Field Camera 3/G141 spectroscopic phase curve observations of two brown dwarfs, WD-0137B and EPIC-2122B, in ultrashort period orbits around white dwarf hosts. These systems are analogous to hot and ultra-hot Jupiter systems, enabling a unique and high-precision comparison …
AstroSat and Insight-HXMT Observations of the Long-period X-Ray Pulsar 4U 2206+54
Wang, Wei; Epili, Prahlad R.
We report the timing and spectral studies of the accreting X-ray pulsar 4U 2206+54 using AstroSat and Insight-HXMT observations taken in 2016 and 2020 respectively. X-ray pulsations from the system are detected by both missions. The AstroSat discovered a significant periodic signal at ∼5619 s in 2016, and Insight-HXMT found a pulsation period at ∼…
Wind-line Variability and Intrinsic Errors in Observational Mass-loss Rates
Massa, Derck; Oskinova, Lidia M.; Prinja, Raman K.
UV wind-line variability in OB stars appears to be universal. In order to quantify this variation and to estimate its effect on a mass-loss rate determined from a single observation, we use the International Ultraviolet Explorer archive to identify nonpeculiar OB stars with well-developed but unsaturated Si IV λ1400 doublets and at least 10 indepe…
Pre-impact Thermophysical Properties and the Yarkovsky Effect of NASA DART Target (65803) Didymos
Kolb, Ulrich C.; Daly, R. Terik; Rivkin, Andrew S. +8 more
The NASA Double Asteroid Redirection Test (DART) spacecraft impacted the secondary body of the binary asteroid (65803) Didymos on 2022 September 26 and altered its orbit about the primary body. Before the DART impact, we performed visible and mid-infrared observations to constrain the pre-impact thermophysical properties of the Didymos system and …
The April 2023 SYM-H = −233 nT Geomagnetic Storm: A Classical Event
Henri, Pierre; Hajra, Rajkumar; Horne, Richard B. +8 more
The 23-24 April 2023 double-peak (SYM-H intensities of −179 and −233 nT) intense geomagnetic storm was caused by interplanetary magnetic field southward component Bs associated with an interplanetary fast-forward shock-preceded sheath (Bs of 25 nT), followed by a magnetic cloud (MC) (Bs of 33 nT), respectively. The…