Search Publications
Quiescent X-ray variability in the neutron star Be/X-ray transient GRO J1750-27
Degenaar, N.; Wijnands, R.; Kaper, L. +5 more
The Be/X-ray transient GRO J1750-27 exhibited a type-II (giant) outburst in 2015. After the source transited to quiescence, we triggered our multi-year Chandra monitoring programme to study its quiescent behaviour. The programme was designed to follow the cooling of a potentially heated neutron-star crust due to accretion of matter during the prec…
AGILE, Fermi, Swift, and GASP/WEBT multi-wavelength observations of the high-redshift blazar 4C +71.07 in outburst
Lähteenmäki, A.; Longo, F.; Morselli, A. +56 more
Context. The flat-spectrum radio quasar 4C +71.07 is a high-redshift (z = 2.172), γ-loud blazar whose optical emission is dominated by thermal radiation from the accretion disc.
Aims: 4C +71.07 has been detected in outburst twice by the AGILE γ-ray satellite during the period from the end of October to mid-November 2015, when it reached a γ-r…
Spot evolution in the eclipsing binary CoRoT 105895502
Schmitt, J. H. M. M.; Czesla, S.; Wichmann, R. +1 more
Stellar activity is ubiquitous in late-type stars. The special geometry of eclipsing binary systems is particularly advantageous to study the stellar surfaces and activity. We present a detailed study of the 145 d CoRoT light curve of the short-period (2.17 d) eclipsing binary CoRoT 105895502. By means of light-curve modeling with Nightfall, we de…
Recovering saturated images for high dynamic kernel-phase analysis. Application to the determination of dynamical masses for the system Gl 494AB
Beuzit, J. -L.; Laugier, R.; Martinache, F. +3 more
Kernel-phase observables extracted from mid- to high-Strehl images are proving to be a powerful tool to probe within a few angular resolution elements of point sources. The attainable contrast is limited, however, by the dynamic range of the imaging sensors. The Fourier interpretation of images with pixels exposed beyond the saturation has so far …
Circumstellar envelopes of semi-regular long-period variables: mass-loss rate estimates and general model fitting of the molecular gas
Alcolea, J.; Santander-García, M.; Bujarrabal, V. +4 more
Aims: We aim to study the main properties of a volume-limited unbiased sample of well-characterized semi-regular variables (SRs) in order to clarify important issues that need to be further explained, such as the formation of axially symmetric planetary nebulae (PNe) from spherical circumstellar envelopes (CSEs), which takes place during the …
Search for water outgassing of (1) Ceres near perihelion
Russell, C. T.; Mousis, O.; Vernazza, P. +13 more
Context. (1) Ceres is the largest body in the main asteroid belt and one of the most intriguing objects in the solar system, in part because of the discovery of water outgassing by the Herschel Space Observatory (HSO) and its still-debated origin. Ceres was the target of NASA's Dawn spacecraft for 3.5 yr, which achieved a detailed characterization…
ATLASGAL-selected massive clumps in the inner Galaxy. VII. Characterisation of mid-J CO emission
König, C.; Menten, K. M.; Csengeri, T. +7 more
Context. High-mass stars are formed within massive molecular clumps, where a large number of stars form close together. The evolution of the clumps with different masses and luminosities is mainly regulated by their high-mass stellar content and the formation of such objects is still not well understood.
Aims: In this work, we characterise th…
Nature of blackbody stars
Serenelli, Aldo; Rohrmann, René D.; Fukugita, Masataka
A selection of 17 stars in the Sloan Digital Sky Survey, previously identified as DC-class white dwarfs (WDs), has been reported to show spectra very close to blackbody radiation in the wavelength range from ultraviolet to infrared. Because of the absence of lines and other details in their spectra, the surface gravity of these objects has previou…
ISPY - NaCo Imaging Survey for Planets around Young stars. A young companion candidate embedded in the R CrA cloud
Quanz, S. P.; Quirrenbach, A.; Henning, T. +13 more
Context. Within the NaCo-ISPY exoplanet imaging program, we aim at detecting and characterizing the population of low-mass companions at wide separations (≳10 AU), focusing in particular on young stars either hosting a known protoplanetary disk or a debris disk.
Aims: R CrA is one of the youngest (1-3 Myr) and most promising objects in our sa…
Accretion disc by Roche lobe overflow in the supergiant fast X-ray transient IGR J08408-4503
Santangelo, A.; Ducci, L.; Romano, P. +1 more
Supergiant fast X-ray transients (SFXTs) are X-ray binary systems with a supergiant companion and likely a neutron star, which show a fast (∼103 s) and high variability with a dynamic range up to 105-6. Given their extreme properties, they are considered among the most valuable laboratories to test accretion models. Recently,…