Search Publications
Extragalactic background light: a measurement at 400 nm using dark cloud shadow*†- I. Low surface brightness spectrophotometry in the area of Lynds 1642
Leinert, Ch.; Väisänen, P.; Lehtinen, K. +2 more
We present the method and observations for the measurement of the Extragalactic Background Light (EBL) utilizing the shadowing effect of a dark cloud. We measure the surface brightness difference between the opaque cloud core and its unobscured surroundings. In the difference the large atmospheric and Zodiacal light components are eliminated and t…
On the possible triple central star system of PN SuWt 2: no ménage à trois at the heart of the Wedding Ring
Jones, David; Boffin, Henri M. J.
SuWt 2 is a planetary nebula consisting of a bright ring-like waist from which protrude faint extended lobes - a morphology believed to be typical of progenitors which have experienced a close-binary evolution. Previous observations of NSV 19992, the star at the projected centre of SuWt 2, have found it to comprise two A-type stars in a 4.9 d ecli…
An analytic method for identifying dynamically formed runaway stars
Perna, Rosalba; Ryu, Taeho; Leigh, Nathan W. C.
In this paper, we study the three-body products (two single stars and a binary) of binary-binary (2+2) scattering interactions. This is done using a combination of analytic methods and numerical simulations of 2+2 scattering interactions, both in isolation and in a homogeneous background potential. We analytically derive a simple formula relating …
The morphological transformation of red sequence galaxies in clusters since z ∼ 1
Demarco, R.; Lidman, C.; Huertas-Company, M. +6 more
The study of galaxy morphology is fundamental to understand the physical processes driving the structural evolution of galaxies. It has long been known that dense environments host high fractions of early-type galaxies and low fractions of late-type galaxies, indicating that the environment affects the structural evolution of galaxies. In this pap…
A flat-spectrum candidate for a track-type high-energy neutrino emission event, the case of blazar PKS 0723-008
Biermann, P. L.; Kun, E.; Gergely, L. Á.
By cross-correlating both the Parkes Catalogue and the Second Planck Catalogue of Compact Sources with the arrival direction of the track-type neutrinos detected by the IceCube Neutrino Observatory, we find the flat-spectrum blazar PKS 0723-008 as a good candidate for the high-energy neutrino event 5 (ID5). Apart from its coordinates matching thos…
Long-term monitoring of comet 67P/Churyumov-Gerasimenko's jets with OSIRIS onboard Rosetta
Jorda, L.; Lamy, P. L.; Lara, L. M. +47 more
We used the OSIRIS camera system onboard the Rosetta spacecraft to monitor jet activity of comet 67P/Churyumov-Gerasimenko. With a monthly cadence, we covered an epoch from 2014 December to 2015 October, thereby including the first equinox and the perihelion passage. Jet features were measured in individual images, which were used to perform a sta…
On the east-west longitudinally asymmetric distribution of solar proton events
Wan, W.; He, H. -Q.
A large data set of 78 solar proton events observed near the Earth's orbit during 1996-2011 is investigated. An east-west longitudinal (azimuthal) asymmetry is found to exist in the distribution of flare sources of solar proton events. With the same longitudinal separation between the flare sources and the magnetic field line footpoint of observer…
Mid-infrared observations of O-type stars: spectral morphology
Bouret, J. -C.; Audard, M.; Lanz, T. +2 more
We present mid-infrared (mid-IR) observations for a sample of 16 O-type stars. The data were acquired with the NASA Spitzer Space Telescope, using the IRS instrument at moderate resolution (R ∼ 600), covering the range of ∼10-37 µm. Our sample includes early, mid and late O supergiants and dwarfs. We explore for the first time their mid-IR s…
Nuclei of dwarf spheroidal galaxies KKs 3 and ESO 269-66 and their counterparts in our Galaxy
Sharina, M. E.; Kniazev, A. Y.; Shimansky, V. V.
We present the analysis of medium-resolution spectra obtained at the Southern African Large Telescope for nuclear globular clusters (GCs) in two dwarf spheroidal galaxies (dSphs). The galaxies have similar star formation histories, but they are situated in completely different environments. ESO 269-66 is a close neighbour of the giant S0 NGC 5128.…
The effect of CO2 on gases trapping in cometary ices
Bar-Nun, A.; Laufer, D.; Ninio Greenberg, A.
Water vapour and CO2 have been detected as the major volatile constituents in the coma of comet 67P/Churyumov-Gerasimenko, by ROSINA (Rosetta Orbiter Spectrometer for Ion and Neutral Analysis) onboard the Rosetta spacecraft. In this paper, we describe experimental results showing the influence of CO2 trapping in amorphous wat…