Search Publications
Star formation in a diffuse high-altitude cloud?
Kerp, J.; Lenz, D.; Röhser, T.
Context. A recent discovery of two stellar clusters associated with the diffuse high-latitude cloud HRK 81.4-77.8 has important implications for star formation in the Galactic halo.
Aims: We derive a plausible distance estimate to HRK 81.4-77.8 primarily from its gaseous properties.
Methods: We spatially correlate state-of-the-art HI, fa…
Iron-rich solar particle events measured by SOHO/ERNE during two solar cycles
Vainio, R.; Valtonen, E.; Raukunen, O.
Aims: We study the differences in the heavy ion composition of solar energetic particle (SEP) events between solar cycles 23 and 24.
Methods: We have surveyed the SOHO/ERNE heavy ion data from the beginning of solar cycle 23 until the end of June 2015, that is, well into the declining phase of cycle 24. We used this long observation peri…
Searching for supergiant fast X-ray transients with Swift
D'Avanzo, P.; Campana, S.; Sbarufatti, B. +11 more
Supergiant fast X-ray transients (SFXTs) are high mass X-ray binaries (HMXBs) hosting a neutron star and an OB supergiant companion. We examine the available Swift data, as well as other new or archival/serendipitous data, on three sources: IGR J17407-2808, 2XMM J185114.3-000004, and IGR J18175-2419, whose X-ray characteristics qualify them as can…
K band SINFONI spectra of two z ~ 5 submillimeter galaxy systems: upper limits to the unobscured star formation from [O II] optical emission line searches
Arribas, Santiago; Colina, Luis; Storchi-Bergmann, Thaisa +2 more
We present deep SINFONI K-band integral field spectra of two submillimeter galaxy systems (SMG): BR 1202-0725 and J1000+0234, at z = 4.69 and 4.55, respectively. Spectra extracted for each object in the two systems do not show any signature of the [O II]λλ3726, 29 Å emission-lines, placing upper flux limits of 3.9 and 2.5 × 10-18erg s
Analysis of luminosity distributions and the shape parameters of strong gravitational lensing elliptical galaxies
Magain, P.; Sluse, D.; Chantry, V. +1 more
Context. The luminosity profiles of galaxies acting as strong gravitational lenses can be tricky to study. Indeed, strong gravitational lensing images display several lensed components, both point-like and diffuse, around the lensing galaxy. Those objects limit the study of the galaxy luminosity to its inner parts. Therefore, the usual fitting met…
The puzzling properties of the magnetic O star Tr16-22
Neiner, Coralie; Morrell, Nidia; Nazé, Yaël +4 more
Context. The detection of bright, hard, and variable X-ray emission in Tr16-22 prompted spectropolarimetric observations of this star, which in turn led to the discovery of a surface magnetic field.
Aims: We want to further constrain the properties of this star, in particular to verify whether X-ray variations are correlated to changes in opt…
Constraints on the dark energy dipole from large-scale structures
Hurier, G.
The high-significance measurement of large-scale structure signals enables testing the isotropy of the Universe. The measurement of cosmological parameters through the large-scale distribution of matter is now a mature domain. This approach is mainly limited by our knowledge of astrophysical processes that are used to observe the large-scale struc…
Hubble imaging of V1331 Cygni: proper motion study of its circumstellar structures
Stecklum, B.; Linz, Hendrik; Choudhary, A.
Aims: The young star V1331 Cyg received previous attention because it is surrounded by an optical, arc-like reflection nebula. V1331 Cyg is commonly considered to be a candidate for an object that has undergone an FU-Ori (FUOR) outbreak in the past. This in turn could lead to a time-varying appearance of the dusty arcs that may be revealed by…
Coronal O VI emission observed with UVCS/SOHO during solar flares: Comparison with soft X-ray observations
Raymond, J. C.; Giordano, S.; Mancuso, S.
In this work, we derive the O VI 1032 Å luminosity profiles of 58 flares, during their impulsive phase, based on off-limb measurements by the Ultraviolet Coronagraph Spectrometer (UVCS) aboard the SOlar and Heliospheric Observatory (SOHO). The O VI luminosities from the transition region plasma (here defined as the region with temperatures 5.0 ≤ l…
Fast inversion of Zeeman line profiles using central moments. II. Stokes V moments and determination of vector magnetic fields
Bommier, V.; Mein, P.; Mein, N. +2 more
Context. In the case of unresolved solar structures or stray light contamination, inversion techniques using four Stokes parameters of Zeeman profiles cannot disentangle the combined contributions of magnetic and nonmagnetic areas to the observed Stokes I.
Aims: In the framework of a two-component model atmosphere with filling factor f, we pr…