Search Publications
Spectral analysis of the dipping LMXB system XB 1916-053
Sanna, A.; Di Salvo, T.; Burderi, L. +6 more
Context. XB 1916-053 is a low mass X-ray binary system (LMXB) hosting a neutron star (NS) and showing periodic dips. The spectrum of the persistent emission was modeled with a blackbody component having a temperature between 1.31 and 1.67 keV and with a Comptonization component with an electron temperature of 9.4 keV and a photon index Γ between 2…
The coronal temperature of NGC 4388 and NGC 2110 measured with INTEGRAL
Bird, A. J.; Ubertini, P.; Malizia, A. +4 more
Aims: We aim to measure the physical properties of the hot X-ray corona of two active galactic nuclei, NGC 4388 and NGC 2110.
Methods: We analysed the hard X-ray (20-300 keV) INTEGRAL spectrum in conjunction with archival XMM-Newton and NuSTAR data.
Results: The X-ray spectrum of both sources is phenomenologically well described by …
Ground-based infrared mapping of H2O2 on Mars near opposition
Aoki, S.; Daerden, F.; Neary, L. +12 more
We pursued our ground-based seasonal monitoring of hydrogen peroxide on Mars using thermal imaging spectroscopy, with two observations of the planet near opposition, in May 2016 (solar longitude Ls = 148.5°, diameter = 17 arcsec) and July 2018 (Ls = 209°, diameter = 23 arcsec). Data were recorded in the 1232-1242 cm-1 range (8.1 µ…
Some relationships between radiative and atmospheric quantities through 1D NLTE modeling of prominences in the Mg II lines
Vial, J. -C.; Zhang, P.; Buchlin, É.
Context. With more than four years of IRIS observations, and in order to avoid building customized diagnostics for each observation, it is useful to derive some simple relations between spectra and physical quantities. This is even more useful for the k and h lines of Mg II, which require complex non-local-thermodynamic-equilibrium NLTE treatments…
Hubble Space Telescope photometry of multiple stellar populations in the inner parts of NGC 2419
Hernandez, Svea; Brodie, Jean; Larsen, Søren S. +2 more
We present new deep imaging of the central regions of the remote globular cluster NGC 2419, obtained with the F343N and F336W filters of the Wide Field Camera 3 on board the Hubble Space Telescope. The new data are combined with archival imaging to constrain nitrogen and helium abundance variations within the cluster. We find a clearly bimodal dis…
Gaia GraL: Gaia DR2 gravitational lens systems. IV. Keck/LRIS spectroscopic confirmation of GRAL 113100-441959 and model prediction of time delays
Djorgovski, S. G.; Stern, D.; Surdej, J. +17 more
We report the spectroscopic confirmation and modeling of the quadruply imaged quasar GRAL 113100-441959, the first gravitational lens (GL) to be discovered from a machine learning technique that only relies on the relative positions and fluxes of the observed images without considering colour informations. Follow-up spectra obtained with Keck/LRIS…
The hierarchical triple nature of the former red nova precursor candidate KIC 9832227
Hartman, Joel D.; Bakos, Gáspár Á.; Kovacs, Geza
We revisit the issue of period variation of the recently claimed red nova precursor candidate KIC 9832227. By using the data gathered during the main mission of the Kepler satellite, and data collected by ground-based wide-field surveys and other monitoring programs (such as ASAS-SN), we find that the currently available timing data strongly suppo…
Surface magnetic activity of the fast-rotating G5 giant IN Comae, central star of the faint planetary nebula LoTr 5
Strassmeier, K. G.; Weber, M.; Ilyin, I. +8 more
Context. On the asymptotic giant branch, low to intermediate mass stars blow away their outer envelopes, forming planetary nebulae. Dynamic interaction between the planetary nebula and its central progenitor is poorly understood. The interaction is even more complex when the central object is a binary star with a magnetically active component, as …
Observability of hydrogen-rich exospheres in Earth-like exoplanets
dos Santos, Leonardo A.; Bourrier, Vincent; Ehrenreich, David +1 more
Context. The existence of an extended neutral hydrogen exosphere around small planets can be used as evidence of the presence of water in their lower atmosphere, but, to date, such a feature has not been securely detected in rocky exoplanets. Planetary exospheres can be observed using transit spectroscopy of the Lyman-α line, which is limited main…
Hot subdwarf wind models with accurate abundances. I. Hydrogen dominated stars HD 49798 and BD+18° 2647
Mereghetti, S.; Pintore, F.; Krtička, J. +5 more
Context. Hot subdwarfs are helium burning objects in late stages of their evolution. These subluminous stars can develop winds driven by light absorption in the lines of heavier elements. The wind strength depends on chemical composition which can significantly vary from star to star.
Aims: We aim to understand the influence of metallicity on…