Search Publications
Distortion of the stellar velocity field parameters due to systematic variations of parallaxes over the celestial sphere
Tsvetkov, A. S.; Vityazev, V. V.
We study the effect of systematic variations in stellar parallaxes over the celestial sphere on the results of a kinematic analysis of stellar proper motions. Our approach is based on the representation of stellar parallaxes by scalar spherical harmonics and on the decomposition of stellar proper motions into a system of vector spherical harmonics…
Operations and performance of the PACS instrument 3He sorption cooler on board of the Herschel space observatory
Poglitsch, A.; Okumura, K.; Sauvage, M. +5 more
A 3He sorption cooler produced the operational temperature of 285 mK for the bolometer arrays of the Photodetector Array Camera and Spectrometer (PACS) instrument of the Herschel Space Observatory. This cooler provided a stable hold time between 60 and 73 h, depending on the operational conditions of the instrument. The respective hold …
Observational dynamics of low-mass stellar systems
Frank, M. J.
The last fifteen years have seen the discovery of new types of low-mass stellar systems that bridge the gap between the once well-separated regimes of galaxies and of star clusters. Whether such objects are considered galaxies depends also on the definition of the term ``galaxy'', and several possible criteria are based on their internal dynamics …
Collisionless resistivity in a bifurcated current sheet
Andriyas, T.; Spencer, E.
The collisionless resistivity due to charged particle chaos in spatially inhomogeneous magnetic fields is calculated for two frequently observed magnetotail current sheets, the X line, and a bifurcated current sheet (BCS) over varying strengths of cross-tail electric field. The calculation is done for two charged species, protons and O+…
Morphology and Structure of Ultraluminous Infrared Galaxies at z ≈ 2 in the EGS Field
Chen, Y.; Kong, X.; Fang, G. W. +1 more
Using high-resolution HST WFC3 (Hubble Space Telescope Wide Field Camera 3) F160W imaging from the CANDELS-EGS (Cosmic Assembly Near-infrared Deep Extragalactic Legacy Survey-Extended Groth Strip) field, we present the morphology analysis of 9 ultraluminous infrared galaxies (ULIRGs) at z≈2. We find a wide range of morphological diversities for th…
Molecular gas associated with IRAS 10361-5830
Rubio, M.; Cappa, C. E.; Vazzano, M. M. +2 more
Aims: We analyze the distribution of the molecular gas and dust in the molecular clump linked to
Herschel/PACS photometry of transiting-planet host stars with candidate warm debris disks
Ardila, David R.; Bouy, Hervé; Stapelfeldt, Karl +4 more
Dust in debris disks is produced by colliding or evaporating planetesimals, which are remnants of the planet formation process. Warm dust disks, known by their emission at ≤24 µm, are rare (4% of FGK main sequence stars) and especially interesting because they trace material in the region likely to host terrestrial planets, where the dust ha…
Stereoscopic observations of the effects of a halo CME on the solar coronal structure
Romano, P.; Spadaro, D.; Dolei, S. +1 more
We investigated the substantial restructuring of the outer solar corona in the aftermath of the halo CME that occurred on 9 March 2012. To perform our analysis, we used SOHO/LASCO, STEREO/COR1 and SDO/AIA data, which provide observations from different viewpoints. In particular, we applied the polarization ratio technique to the COR1 calibrated im…
A Herschel PACS survey of brown dwarfs in IC 2391: limits on primordial and debris disc fractions
Riaz, B.; Kennedy, G. M.
We present results from a Herschel Photodetector Array Camera and Spectrometer (PACS) survey of eight brown dwarfs in the IC 2391 cluster. Our aim was to determine the brown dwarf disc fraction at ages of ∼40-50 Myr. None of the eight brown dwarfs observed were detected in the PACS 70 or 160 µm bands. We have determined the detection limits …
Herschel Photometry of Disks around Low-mass Stars in the R CrA Cloud
Henning, Thomas; Liu, Yao; Wolf, Sebastian +1 more
We report photometric results from a subset of a Herschel-PACS program to observe cool dust in disks around low-mass stars as a complement to our earlier program to measure far-infrared emission from brown dwarfs. In this latest study we observed five low-mass objects in the nearby R Corona Australis region and detected at least three at 70 µ…