Search Publications
Unraveling the inner substructure of new candidate hub-filament system in the H II region G25.4NW
Dewangan, L. K.
We present multiscale and multiwavelength data of the Galactic H II region G25.4-0.14 (hereafter G25.4NW, distance ~5.7 kpc). The SHARC-II 350-µm continuum map displays a hub-filament configuration containing five parsec-scale filaments and a central compact hub. Through the 5-GHz radio continuum map, four ionized clumps (i.e. Ia-Id) are ide…
Four new planetesimals around typical and pre-main-sequence stars (PLATYPUS) debris discs at 8.8 mm
Duchêne, Gaspard; Wilner, David J.; Matthews, Brenda +9 more
Millimetre continuum observations of debris discs can provide insights into the physical and dynamical properties of the unseen planetesimals that these discs host. The material properties and collisional models of planetesimals leave their signature on the grain size distribution, which can be traced through the millimetre spectral index. We pres…
Cosmography using strong-lensing systems and cosmic chronometers
Motta, V.; Lizardo, Andrés; Amante, Mario H. +2 more
Using a new sub-sample of observed strong gravitational lens systems, for the first time, we present the equation for the angular diameter distance in the y-redshift scenario for cosmography and use it to test the cosmographic parameters. In addition, we also use the observational Hubble data from cosmic chronometers and a joint analysis of both d…
Precise diffusion coefficients for white dwarf astrophysics
Caplan, M. E.; Freeman, I. F.
Observations of Galactic white dwarfs with Gaia have allowed for unprecedented modelling of white dwarf cooling, resolving core crystallization, and sedimentary heating from neutron-rich nuclei. These cooling sequences are sensitive to the diffusion coefficients of nuclei in Coulomb plasmas which have order 10 per cent uncertainty and are often no…
Morphological and kinematical analysis of the double-barred galaxy NGC 3504 using ALMA CO (2-1) data
Miyamoto, Yusuke; Espada, Daniel; Trejo, Alfonso +1 more
We present results obtained from ALMA CO (2-1) data of the double-barred galaxy NGC 3504. With three times higher angular resolution (~0${_{.}^{\prime\prime}}$8) than previous studies, our observations reveal an inner molecular gas bar, a nuclear ring, and four inner spiral arm-like structures in the central 1-kpc region. Furthermore, the CO emiss…
Dipper-like variability of the Gaia alerted young star V555 Ori
Pál, András; Moór, Attila; Ábrahám, Péter +26 more
V555 Ori is a T Tauri star, whose 1.5 mag brightening was published as a Gaia science alert in 2017. We carried out optical and near-infrared (NIR) photometric, and optical spectroscopic observations to understand the light variations. The light curves show that V555 Ori was faint before 2017, entered a high state for about a year, and returned to…
Orbital pericentres and the inferred dark matter halo structure of satellite galaxies
Bullock, James S.; Robles, Victor H.
Using the phat-ELVIS suite of Milky Way-sized halo simulations, we show that subhalo orbital pericentres, rperi, correlate with their dark matter halo structural properties. Specifically, at fixed maximum circular velocity, Vmax, subhaloes with smaller rperi are more concentrated (have smaller rmax value…
Flow directions of low-energy ions in and around the diamagnetic cavity of comet 67P
Nilsson, Hans; Stenberg Wieser, Gabriella; Wieser, Martin +5 more
The flow direction of low-energy ions around comet 67P/Churyumov-Gerasimenko has previously been difficult to constrain due to the influence of the spacecraft potential. The Ion Composition Analyzer of the Rosetta Plasma Consortium (RPC-ICA) on Rosetta measured the distribution function of positive ions with energies down to just a few eV/q throug…
UV and X-ray observations of the neutron star LMXB EXO 0748-676 in its quiescent state
Degenaar, N.; Wijnands, R.; Costantini, E. +5 more
The accretion behaviour in low-mass X-ray binaries (LMXBs) at low luminosities, especially at <1034 erg s-1, is not well known. This is an important regime to study to obtain a complete understanding of the accretion process in LMXBs, and to determine if systems that host neutron stars with accretion-heated crusts can be u…
HERMES spectroscopy of normal A and Am stars
Joshi, Santosh; De Cat, Peter; Lampens, Patricia +2 more
The nominal Kepler mission provided very high precision photometric data. Using these data, interesting phenomena such as spots, and 'hump and spike' features were observed in the light curves of some normal A and metallic lined A stars (Am stars). However, the connection between such phenomena and the chemical peculiarity of the Am stars is still…