Search Publications
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…
Jet‑triggered star formation in young radio galaxies
Baum, Stefi; Morganti, Raffaella; Tremblay, Grant +7 more
Emission in the ultraviolet continuum is a salient signature of the hot, massive and consequently short-lived, stellar population that traces recent or ongoing star formation. With the aim of mapping star forming regions and morphologically separating the generic star formation from that associated with the galaxy-scale jet activity, we obtained h…
K-band GRAVITY/VLTI interferometry of "extreme" Herbig Be stars. The size-luminosity relation revisited
Montesinos, B.; Mendigutía, I.; Vioque, M. +7 more
Context. It has been hypothesized that the location of Herbig Ae/Be stars (HAeBes) within the empirical relation between the inner disk radius (rin), inferred from K-band interferometry, and the stellar luminosity (L*), is related to the presence of the innermost gas, the disk-to-star accretion mechanism, the dust disk proper…
Multi-Instrument Investigation of the Impact of the Space Weather Events of 6-10 September 2017
Simi, K. G.; Amaechi, Paul O.; Akala, Andrew O. +3 more
We analyzed the space weather events of 6-10 September 2017 using the multi-instrument approach. We focused on the four X-class flares which emanated from the Active Region AR 12673 and the Ground Induced Currents hazard associated with the geomagnetic storm of 7-8 September 2017. The flare effect on the equatorial electrojet (EEJ) recorded on boa…
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…
Observation and calibration strategies for large-scale multi-beam velocity-resolved mapping of the [CII] emission in the Orion molecular cloud
Teyssier, D.; Goicoechea, J. R.; Stutzki, J. +15 more
Context. The [CII] 158 µm far-infrared fine-structure line is one of the dominant cooling lines of the star-forming interstellar medium. Hence [CII] emission originates in and thus can be used to trace a range of ISM processes. Velocity-resolved large-scale mapping of [CII] in star-forming regions provides a unique perspective of the kinemat…
A Radiatively Driven Wind from the η Tel Debris Disk
MacGregor, Meredith A.; Weinberger, Alycia J.; Roberge, Aki +5 more
We present far- and near-ultraviolet absorption spectroscopy of the ~23 Myr edge-on debris disk surrounding the A0V star η Telescopii, obtained with the Hubble Space Telescope Space Telescope Imaging Spectrograph. We detect absorption lines from C I, C II, O I, Mg II, Al II, Si II, S II, Mn II, Fe II, and marginally N I. The lines show two clear a…
The case for thermalization as a contributor to the [C II] deficit
Hunt, Leslie K.; Calzetti, Daniela; De Looze, Ilse +15 more
The [C II] deficit, which describes the observed decrease in the ratio of [C II] 158 µm emission to continuum infrared emission in galaxies with high star formation surface densities, places a significant challenge to the interpretation of [C II] detections from across the observable universe. In an attempt to further decode the cause of the…
Influence of Heliolatitudinal Anisotropy of Solar FUV/EUV Emissions on Lyα Helioglow: SOHO/SWAN Observations and WawHelioGlow Modeling
Bzowski, M.; Kubiak, M. A.; Strumik, M.
Observations of the Sun's surface suggest a nonuniform radiated flux as related to the presence of bright active regions and darker coronal holes. The variations of the FUV/EUV source radiation can be expected to affect the Lyα backscatter glow measured by spaceborne instruments. In particular, inferring the heliolatitudinal structure of the solar…
Hunt for extremely eccentric eclipsing binaries
Mašek, M.; Zasche, P.; Henzl, Z.
We report the very first analysis of 27 eclipsing binary systems with high eccentricities that sometimes reach up to 0.8. The orbital periods for these systems range from 1.4 to 37 days, and the median of the sample is 10.3 days. Star CzeV3392 (= UCAC4 623 022784), for example, currently is the eclipsing system with the highest eccentricity (e = 0…