Search Publications
The peculiar ejecta of the nova V1425 Aquilae
Schmidtobreick, L.; Celedón, L.; Tappert, C.
Many important details of the mechanisms underlying the ejection of material during a (classical) nova eruption are still not understood. Here we present optical spectroscopy and narrow-band images of the nova V1425 Aql, 23 yr after the nova eruption. We find that the ejecta consist of two significantly different components. The first resembles wh…
Determination of the eddy diffusion in the Venusian clouds from VeRa sulfuric acid observations
Sheng, Zheng; Dai, Longkang; Shao, Wencheng +1 more
Context. The vertical eddy diffusion coefficient (Kzz) characterizing the efficiency of vertical atmospheric mixing is essential for 1D planetary atmospheric modeling, but poorly constrained in the Venusian clouds, where our ability to observe tracer gases is limited. The Venusian clouds are mainly composed of H2SO4
Convective blueshift strengths for 242 evolved stars
Reiners, A.; Zechmeister, M.; Jeffers, S. V. +1 more
Context. With the advent of extreme precision radial velocity (RV) surveys, seeking to detect planets at RV semi-amplitudes of 10 cm s−1, intrinsic stellar variability is the biggest challenge to detecting small exoplanets. To overcome the challenge we must first thoroughly understand all facets of stellar variability. Among those, conv…
High-precision broadband linear polarimetry of early-type binaries. IV. The DH Cephei binary system in the open cluster of NGC 7380
Piirola, Vilppu; Berdyugin, Andrei V.; Sakanoi, Takeshi +2 more
Aims: DH Cephei is a well-known massive O+O-type binary system on the northern sky, situated at the center of young open cluster NGC 7380. Our high-precision multi-band polarimetry clearly reveals that variations of linear polarization in this system are synchronous with the phase of the orbital period. We used the observed variations of Stok…
Likelihood of the sky. Bayesian treatment of the geometric two-catalog matching problem
Schmitt, J. H. M. M.; Salvato, M.; Buchner, J. +4 more
Catalogs with celestial positions and uncertainties are among the primary data products of observational astronomy. Consequently, the (cross-)matching problem, namely, the question of how many (and which) pairs of positions pertain to the same celestial source, remains a central part of this scientific exploitation. We address the matching problem…
Identification of large equivalent width dusty galaxies at 4 < z < 6 from sub-millimetre colours
Buat, V.; Boquien, M.; Burgarella, D. +8 more
Context. Infrared (IR), sub-millimetre (sub-mm), and millimetre (mm) databases contain a huge quantity of high-quality data. However, a large part of these data are photometric, and they are thought not to be useful to derive quantitative information on the nebular emission of galaxies.
Aims: The aim of this project is first to identify galax…
Gaia Focused Product Release: Spatial distribution of two diffuse interstellar bands
Prusti, T.; Mazeh, T.; Zucker, S. +402 more
Diffuse interstellar bands (DIBs) are absorption features seen in optical and infrared spectra of stars and extragalactic objects that are probably caused by large and complex molecules in the galactic interstellar medium (ISM). Here we investigate the Galactic distribution and properties of two DIBs identified in almost six million stellar spectr…
Multi-point study of the energy release and impulsive CME dynamics in an eruptive C7 flare
Krucker, Säm; Veronig, Astrid M.; Podladchikova, Tatiana +6 more
Context. The energy release in eruptive flares and the kinematics of the associated coronal mass ejections (CMEs) are interlinked and require favorable observing positions as both on-disk and off-limb signatures are necessary to characterize these events.
Aims: We combine observations from different vantage points to perform a detailed study …
The possible evolution of pitch angles of spiral galaxies
Reshetnikov, V. P.; Marchuk, A. A.; Mosenkov, A. V. +2 more
Aims: The origin and maintenance of spiral structure in galaxies, the correlation between different types of spiral structure and several proposed mechanisms for their generation, and the evolution of spiral arms of galaxies with time are questions that are still controversial. In this note we study the spiral structure in a sample of distant…
The star in RNO 54: A possible post-FUor with a short faint jet
Moiseev, A. V.; Magakian, T. Yu.; Movsessian, T. A. +2 more
Aims: The aim of the present study is to analyze the spectra of an unusual pre-main sequence star in the cometary nebula RNO 54, which is suspected by several researchers to be a FUori-like object.
Methods: We performed long-slit spectroscopy of the star using the 6m telescope with the SCORPIO-2 multi-mode focal reducer.
Results: We…