Search Publications
The GALAH survey: a catalogue of carbon-enhanced stars and CEMP candidates
Lewis, Geraint F.; Ting, Yuan-Sen; Buder, Sven +20 more
Swan bands - characteristic molecular absorption features of the C2 molecule - are a spectroscopic signature of carbon-enhanced stars. They can also be used to identify carbon-enhanced metal-poor (CEMP) stars. The GALAH (GALactic Archaeology with Hermes) is a magnitude-limited survey of stars producing high-resolution, high-signal-to-no…
Observations on a Series of Merging Magnetic Flux Ropes Within an Interplanetary Coronal Mass Ejection
Zhao, Yan; Feng, Hengqiang; Zhao, Guoqing +2 more
Coronal mass ejections (CMEs) are intense solar explosive eruptions. CMEs are highly important players in solar-terrestrial relationships, and they have important consequences for major geomagnetic storms and energetic particle events. It has been unclear how CMEs evolve when they propagate in the heliosphere. Here we report an interplanetary CME …
First stellar occultation by the Galilean moon Europa and upcoming events between 2019 and 2021
Maury, A.; Cacella, P.; Lainey, V. +21 more
Context. Bright stellar positions are now known with an uncertainty below 1 mas thanks to Gaia DR2. Between 2019-2020, the Galactic plane will be the background of Jupiter. The dense stellar background will lead to an increase in the number of occultations, while the Gaia DR2 catalogue will reduce the prediction uncertainties for the shadow path. …
On the possibility of detecting ultrashort period exoplanets with LISA
Wong, Kaze W. K.; Berti, Emanuele; Gabella, William E. +1 more
Cunha, Silva & Lima recently reexamined the possibility of detecting gravitational waves from exoplanets, claiming that three ultrashort period systems would be observable by LISA. We revisit their analysis and conclude that the currently known exoplanetary systems are unlikely to be detectable, even assuming a LISA observation time Tobs<…
Formation of the Y Feature at the Venusian Cloud Top by Planetary-Scale Waves and the Mean Circulation: Analysis of Venus Express VMC Images
Kouyama, T.; Yamada, M.; Nara, Y. +6 more
The relationship between the planetary-scale ultraviolet contrast known as the Y feature and the wind field at the Venusian cloud top was investigated by using images obtained by Venus Monitoring Camera (VMC) on ESA's Venus Express. Spectral analyses of the ultraviolet reflectivity and the wind field revealed common periodicities of 4-5 Earth days…
Variations on a theme: the puzzling behaviour of Schulte 12
Nazé, Yaël; Mahy, Laurent; Rauw, Gregor +2 more
One of the first massive stars detected in X-rays, Schulte 12 has remained a puzzle in several aspects. In particular, its extreme brightness both in the visible and X-ray ranges is intriguing. Thanks to Swift and XMM-Newton observations covering ∼5000 d, we report the discovery of a regular 108 d modulation in X-ray flux of unknown origin. The mi…
Metallicity Gradients in M 31, M 33, NGC 300 and the Milky Way Using Abundances of Different Elements
Peña, M.; Flores-Durán, S. N.
Metallicity gradients derived from planetary nebulae (PNe) using O, Ne, and Ar abundances are studied and compared to those from H II regions in the galaxies M 31, M 33, NGC 300 and the Milky Way. Galactocentric radii and chemical abundances were collected from the literature, carefully selecting a homogeneous sample for each galaxy. Metallicity g…
A Cepheid-based Distance to the Seyfert Galaxy NGC 6814
Peterson, Bradley M.; Ferrarese, Laura; Onken, Christopher A. +2 more
We present a Cepheid-based distance to the nearby Seyfert galaxy NGC 6814 from Hubble Space Telescope observations. We obtained F555W and F814W imaging over the course of 12 visits with logarithmic time spacing in 2013 August-October. We detected and made photometric measurements for 16,469 unique sources across all images in both filters, from wh…
COS Observations of the Cosmic Web: A Search for the Cooler Components of a Hot, X-Ray Identified Filament
Zahedy, Fakhri S.; Chen, Hsiao-Wen; Mulchaey, John S. +3 more
In the local universe, a large fraction of the baryon content is believed to exist as diffuse gas in filaments. While this gas is directly observable in X-ray emission around clusters of galaxies, it is primarily studied through its UV absorption. Recently, X-ray observations of large-scale filaments connecting to the cosmic web around the nearby …
Electron Acceleration in Middle-age Shell-type γ-Ray Supernova Remnants
Zhang, Xiao; Liu, Siming
Over the past decade, γ-ray observations of supernova remnants (SNRs) and accurate cosmic-ray (CR) spectral measurements have significantly advanced our understanding of particle acceleration in SNRs. In combination with multiwavelength observations of a large sample of SNRs, it has been proposed that the highest energy particles are mostly accele…