Search Publications
A shock near the virial radius of the Perseus Cluster
Simionescu, A.; Kaastra, J. S.; Zhang, X. +6 more
Context. Previous X-ray studies of the Perseus Cluster, consisting of 85 Suzaku pointings along eight azimuthal directions, revealed a particularly steep decrease in the projected temperature profile near the virial radius (∼r200) towards the northwest (NW).
Aims: To further explore this shock candidate, another 4 Suzaku observatio…
The first heavy-metal hot subdwarf composite binary SB 744
Bastian, A.; Németh, P.; Vos, J. +1 more
Aims: The long-period sdOB+G1V type spectroscopic binary SB 744 reveals strong lines of fluorine and lead in the optical spectrum of the sdOB star and subsolar metallicity in the G1V companion thanks to a radial velocity follow-up study. Using high-quality observations and Gaia astrometric data, we aim to measure the chemical composition and …
The CARMA-NRO Orion Survey: Filament Formation via Collision-induced Magnetic Reconnection—the Stick in Orion A
Mairs, Steve; Nakamura, Fumitaka; Klessen, Ralf S. +13 more
A unique filament is identified in the Herschel maps of the Orion A giant molecular cloud. The filament, which we name the Stick, is ruler-straight and at an early evolutionary stage. Transverse position-velocity diagrams show two velocity components closing in on the Stick. The filament shows consecutive rings/forks in C18O (1-0) chann…
Hamilton's Object - a clumpy galaxy straddling the gravitational caustic of a galaxy cluster: constraints on dark matter clumping
Griffiths, Richard E.; Villforth, Carolin; Wagner, Jenny +3 more
We report the discovery of a 'folded' gravitationally lensed image, 'Hamilton's Object', found in a HST image of the field near the active galactic nucleus SDSS J223010.47-081017.8 (which has redshift 0.62). The lensed images are sourced by a galaxy at a spectroscopic redshift of 0.8200 ± 0.0005 and form a fold configuration on a caustic caused by…
The nearby magnetic cool DZ white dwarf PM J08186-3110
Vennes, Stéphane; Allard, Nicole F.; Kawka, Adela +2 more
We present an analysis of photometric, spectroscopic, and spectropolarimetric data of the nearby, cool, magnetic DZ white dwarf PM J08186-3110. High-dispersion spectra show the presence of Zeeman splitted spectral lines due to the presence of a surface average magnetic field of 92 kG. The strong magnesium and calcium lines show extended wings shap…
Metallicity and X-ray luminosity variations in NGC 922
Zezas, A.; Wolter, A.; Fruscione, A. +3 more
We present a systematic study of the metallicity variations within the collisional ring galaxy NGC 922 based on long-slit optical spectroscopic observations. We find a metallicity difference between star-forming regions in the bulge and the ring, with metallicities ranging from almost solar to significantly sub-solar ( $\rm {[12+\log (O/H)]\sim 8.…
HCT/HESP study of two carbon stars from the LAMOST survey
Shi, Jianrong; Shejeelammal, J.; Goswami, Aruna
Carbon stars, enhanced in carbon and neutron-capture elements, provide a wealth of information about the nucleosynthesis history of the Galaxy. In this work, we present the first ever detailed abundance analysis of the carbon star LAMOSTJ091608.81+230734.6 and a detailed abundance analysis of neutron-capture elements for the object LAMOSTJ151003.7…
AB Aurigae: possible evidence of planet formation through the gravitational instability
Cadman, James; Hall, Cassandra; Rice, Ken
Recent observations of the protoplanetary disc surrounding AB Aurigae have revealed the possible presence of two giant planets in the process of forming. The young measured age of 1-4 Myr for this system allows us to place strict time constraints on the formation histories of the observed planets. Hence, we may be able to make a crucial distinctio…
Stellar population astrophysics (SPA) with the TNG. The Arcturus Lab
Dalessandro, E.; Sanna, N.; Mucciarelli, A. +4 more
Context. High-resolution spectroscopy in the near-infrared (NIR) is a powerful tool for characterising the physical and chemical properties of cool-star atmospheres. The current generation of NIR echelle spectrographs enables the sampling of many spectral features over the full 0.9-2.4 µm range for a detailed chemical tagging.
Aims: Wit…
Middle aged γ-ray pulsar J1957+5033 in X-rays: pulsations, thermal emission, and nebula
Karpova, A. V.; Zyuzin, D. A.; Suleimanov, V. F. +2 more
We analyse new XMM-Newton and archival Chandra observations of the middle-aged γ-ray radio-quiet pulsar J1957+5033. We detect, for the first time, X-ray pulsations with the pulsar spin period of the point-like source coinciding by position with the pulsar. This confirms the pulsar nature of the source. In the 0.15-0.5 keV band, there is a single p…