Search Publications
An HST/COS legacy survey of intervening Si III absorption in the extended gaseous halos of low-redshift galaxies
Wakker, B. P.; Fechner, C.; Richter, P. +3 more
Aims: Doubly ionized silicon (Si III) is a powerful tracer of diffuse ionized gas inside and outside of galaxies. It can be observed in the local Universe in ultraviolet (UV) absorption against bright extragalactic background sources. We here present an extensive study of intervening Si III-selected absorbers and study the properties of the w…
The Lyman alpha reference sample. VI. Lyman alpha escape from the edge-on disk galaxy Mrk 1486
Verhamme, Anne; Cannon, John M.; Hayes, Matthew +16 more
Context. Recent numerical simulations suggest that the strength of the Lyman alpha (Lyα) line of star-forming disk galaxies strongly depends on the inclination at which they are observed: from edge-on to face-on, we expect to see a change from a strongly attenuated Lyα line to a strong Lyα emission line.
Aims: We aim to understand how a stron…
The gamma-ray emitting radio-loud narrow-line Seyfert 1 galaxy PKS 2004-447. I. The X-ray View
Gehrels, N.; Wilms, J.; Kadler, M. +11 more
As part of the TANAMI multiwavelength progam, we discuss new X-ray observations of the γ-ray and radio-loud narrow line Seyfert 1 galaxy (γ-NLS1) PKS 2004-447. The active galaxy is a member of a small sample of radio-loud NLS1s detected in γ-rays by the Fermi Large Area Telescope. It stands out for being the radio-loudest and the only southern-hem…
Pulsating hot O subdwarfs in ω Centauri: mapping a unique instability strip on the extreme horizontal branch
Dhillon, V. S.; Chayer, P.; Fontaine, G. +10 more
We present the results of an extensive survey for rapid pulsators among Extreme Horizontal Branch (EHB) stars in ω Cen. The observations performed consist of nearly 100 h of time-series photometry for several off-centre fields of the cluster, as well as low-resolution spectroscopy for a partially overlapping sample. We obtained photometry for some…
Nine new open clusters within 500 pc from the Sun
Goldman, Bertrand; Röser, Siegfried; Schilbach, Elena
Aims: One of the results of the Milky Way Star Clusters (MWSC) survey was the detection of a slight under-density of old (ca. 1 Gyr) clusters within the nearest kilo-parsec from the Sun. This under-density may be due to an ineffectiveness in the detection of larger structures with lower surface brightness. We report on our attempts to reveal …
X-ray analysis of the galaxy group UGC 03957 beyond R200 with Suzaku
Thölken, Sophia; Reiprich, Thomas H.; Lovisari, Lorenzo +1 more
Context. In the last few years, the outskirts of galaxy clusters have been studied in detail and the analyses have brought up interesting results such as indications of possible gas clumping and the breakdown of hydrostatic, thermal, and ionization equilibrium. These phenomena affect the entropy profiles of clusters, which often show deviations fr…
Highly ionized region surrounding SN Refsdal revealed by MUSE
Treu, T.; Grillo, C.; Balestra, I. +9 more
Supernova (SN) Refsdal is the first multiply imaged, highly magnified, and spatially resolved SN ever observed. The SN exploded in a highly magnified spiral galaxy at z = 1.49 behind the Frontier Fields cluster MACS1149, and provides a unique opportunity to study the environment of SNe at high z. We exploit the time delay between multiple images t…
Physical properties and dynamical relation of the circular depressions on comet 67P/Churyumov-Gerasimenko
Jorda, L.; Lamy, P. L.; Lara, L. M. +52 more
Aims: We aim to characterize the circular depressions of comet 67P/Churyumov-Gerasimenko and investigate whether such surface morphology of a comet nucleus is related to the cumulative sublimation effect since becoming a Jupiter family comet (JFC).
Methods: The images from the Rosetta/OSIRIS science camera experiment are used to construc…
Mid-IR spectra of pre-main sequence Herbig stars: An explanation for the non-detections of water lines
Woitke, P.; Kamp, I.; Güdel, M. +7 more
Context. The mid-IR detection rate of water lines in disks around Herbig stars disks is about 5%, while it is around 50% for disks around T Tauri stars. The reason for this is still unclear.
Aims: In this study, we want to find an explanation for the different detection rates between low mass and high mass pre-main-sequence stars in the mid-I…
Effects of flare definitions on the statistics of derived flare distributions
Stegen, K.; Dominique, M.; Ryan, D. F. +2 more
The statistical examination of solar flares is crucial to revealing their global characteristics and behaviour. Such examinations can tackle large-scale science questions or give context to detailed single-event studies. However, they are often performed using standard but basic flare detection algorithms relying on arbitrary thresholds. This arbi…