Search Publications
The Correspondence Between Sudden Commencements and Geomagnetically Induced Currents: Insights From New Zealand
Forsyth, C.; Rae, I. J.; Smith, A. W. +6 more
Variability of the geomagnetic field induces anomalous Geomagnetically Induced Currents (GICs) in grounded conducting infrastructure. GICs represent a serious space weather hazard but are not often measured directly and the rate of change of the magnetic field is often used as a proxy. We assess the correlation between the rate of change of the ma…
Nebular abundance gradient in the Cartwheel galaxy using MUSE data
Ramos-Larios, Gerardo; Mayya, Divakara; Zaragoza-Cardiel, Javier +1 more
We here present the results from a detailed analysis of nebular abundances of commonly observed ions in the collisional ring galaxy Cartwheel using the Very Large Telescope (VLT) Multi-Unit Spectroscopic Explorer (MUSE) data set. The analysis includes 221 H II regions in the star-forming ring, in addition to 40 relatively fainter H α-emitting regi…
Forbush decreases associated with coronal mass ejections from active and non-active regions: statistical comparison
Melkumyan, A. A.; Belov, A. V.; Abunina, M. A. +4 more
In this paper, Forbush decreases (FDs) from 1997 to 2020 associated with coronal mass ejections from active and non-active regions are compared between themselves and to FDs caused by high-speed streams from coronal holes. The two types of sporadic FDs are also compared when corresponding solar wind (SW) disturbances contain, or do not contain, ma…
Accretion variability in RU Lup
Ray, T. P.; Natta, A.; Caratti o Garatti, A. +2 more
Context. The process of accretion in classical T Tauri stars (CTTSs) has been observed to vary on different timescales. Studying this variability is vital to understanding a star's evolution and provides insight into the complex processes at work within, including sources of the veiling present. Understanding the dichotomy between continuum veilin…
Topography of the Young Galactic Disk: Spatial and Kinematic Patterns of Clustered Star Formation in the Solar Neighborhood
González, Marta; Alfaro, Emilio J.; Sánchez-Gil, M. Carmen +3 more
The accuracy in determining the spatial-kinematical parameters of open clusters makes them ideal tracers of the Galactic structure. Young open clusters (YOCs) are the main representatives of the clustered star formation mode, which identifies how most of the stars in the Galaxy form. We apply the Kriging technique to a sample of Gaia YOCs within a…
CO line observations of OH/IR stars in the inner Galactic Bulge: Characteristics of stars at the tip of the AGB
Blommaert, J. A. D. L.; Ryde, N.; Olofsson, H. +10 more
Context. OH/IR stars are examples of late stellar evolution on the asymptotic giant branch (AGB), and they are, as such, important objects to study. They are also excellent probes of stellar populations, in particular in regions of high interstellar extinction such as the central regions of our Galaxy.
Aims: Our goal is to characterise the st…
Lithium abundances as a tracer of asymptotic giant branch star pollution in the globular cluster NGC 6752
Lucatello, Sara; Pietrinferni, Adriano; Rain, M. J. +1 more
This paper presents a chemical abundance analysis of 217 stars in the metal-poor globular cluster NGC 6752, distributed from the turn-off to the lower red giant branch. Al and Li abundances were derived through spectral synthesis applied to spectra collected with FLAMES, in both GIRAFFE and UVES modes. The work aims to gain insight into the nature…
Dissecting the Extended X-Ray Emission in the Merging Pair NGC 6240: Photoionization and Winds
Elvis, M.; Fabbiano, G.; Nardini, E. +3 more
We present a detailed spectral and imaging analysis of the central 15″ radius (~7.5 kpc) region of the merger galaxy NGC 6240 that makes use of all the available Chandra-ACIS data (0.3-3 keV effective exposure of ~190 ks). This region shows extended X-ray structures with lower-energy counterparts imaged in CO, [O III], and Hα line emission. We fin…
Orbital parameters and activity of ZZ Tau - a low-mass young binary with circumbinary disc
Safonov, B.; Belinski, A.; Emelyanov, N. +5 more
We present the results of our new observations of the young binary ZZ Tau with a circumbinary disc. The system was found to consist of two coeval (age < 2 Myr) classical T Tauri stars with the total mass 0.86 ± 0.09 M⊙, orbital period 46.8 ± 0.8 yr, semimajor axis 88.2 ± 2.1 mas, eccentricity 0.58 ± 0.02, and the orbital inclination …
The recurrent nova U Scorpii from the 2010.1 to 2022.4 eruptions; the missed eruption of 2016.78 ± 0.10 and the critical complex period changes
Schaefer, Bradley E.
U Sco is a recurrent nova with 11 observed eruptions, most recently in 2010.1 and 2022.4. I report on my program (running since 1989) of measuring eclipse times and brightnesses of U Sco in quiescence, from 2010 to 2022. The orbital period suddenly increased by +22.4 ± 1.0 parts-per-million across the 2010.1 eruption. This period change is greater…