Search Publications
VEGAS-SSS. A VST early-type galaxy survey: analysis of small stellar systems. Testing the methodology on the globular cluster system in NGC 3115
Forbes, Duncan A.; Romanowsky, Aaron J.; Puzia, Thomas H. +11 more
We present a study of globular clusters (GCs) and other small stellar systems (SSSs) in the field of NGC 3115, observed as part of the ongoing wide-field imaging survey VEGAS, carried out with the 2.6 m VST telescope. We used deep g and i observations of NGC 3115, a well-studied lenticular galaxy that is covered excellently well in the scientific …
Photometric analysis of Asteroid (21) Lutetia from Rosetta-OSIRIS images
Vincent, J. -B.; Masoumzadeh, N.; Li, Jian-Yang +1 more
We analyzed the photometric properties of Asteroid (21) Lutetia based on images captured by Rosetta during its flyby. We utilized the images recorded in the F17 filter (λ = 631.6 nm) of the Wide Angle Camera (WAC) and in the F82 & F22 filters (λ = 649.2 nm) of the Narrow Angle Camera (NAC) of the OSIRIS imaging system onboard the spacecraft. W…
Gas phase dicyanoacetylene (C4N2) on Titan: New experimental and theoretical spectroscopy results applied to Cassini CIRS data
Jolly, A.; Cottini, V.; Irwin, P. +6 more
Dicyanoacetylene has not been observed so far in the gas phase in Titan's atmosphere but this molecule is still on the list of the detected species, on the basis of the correspondence between a solid phase feature measured at 478 cm-1 in the laboratory and a spectral feature observed by Voyager. In this work, the infrared spectrum of ga…
CMB low multipole alignments in the ΛCDM and dipolar models
Gruppuso, A.; Natoli, P.; Polastri, L.
The dipolar model [1] has attracted much interest because it may phenomenologically explain the CMB hemispherical power asymmetry found in the WMAP and Planck data. Since such a model explicitly breaks isotropy at large angular scales it is natural to wonder whether it can also explain other CMB directional anomalies. Focusing on the low ℓ alignme…
Observation and numerical modeling of chromospheric evaporation during the impulsive phase of a solar flare
Watanabe, Tetsuya; Murakami, Izumi; Imada, Shinsuke
We have studied the chromospheric evaporation flow during the impulsive phase of the flare by using the Hinode/EUV Imaging Spectrometer observation and 1D hydrodynamic numerical simulation coupled to the time-dependent ionization. The observation clearly shows that the strong redshift can be observed at the base of the flaring loop only during the…
Searches for Millisecond Pulsar Candidates among the Unidentified Fermi Objects
Cheng, K. S.; Takata, J.; Kong, A. K. H. +9 more
Here we report the results of searching millisecond pulsar (MSP) candidates from the Fermi LAT second source catalog (2FGL). Seven unassociated γ-ray sources in this catalog are identified as promising MSP candidates based on their γ-ray properties. Through the X-ray analysis, we have detected possible X-ray counterparts, localized to an arcsecond…
A high-resolution wide-field radio survey of M51
Argo, M. K.; Soria, R.; Tingay, S. J. +4 more
We present the highest resolution, wide-field radio survey of a nearby face-on star-forming galaxy to date. The multiphase centre technique is used to survey the entire disc of M51 (77 arcmin2) at a maximum resolution of 5 mas on a single 8 h pointing with the European Very Long Baseline Interferometry (VLBI) Network at 18 cm. In total,…
The Role of Large Amplitude Upstream Low-frequency Waves in the Generation of Superthermal Ions at a Quasi-parallel Collisionless Shock: Cluster Observations
Wang, Shui; Huang, Can; Guo, Fan +3 more
The superthermal ions at a quasi-parallel collisionless shock are considered to be generated during the reformation of the shock. Recently, hybrid simulations of a quasi-parallel shock have shown that during the reformation of a quasi-parallel shock the large-amplitude upstream low-frequency waves can trap the reflected ions at the shock front whe…
Eta Carinae’s 2014.6 Spectroscopic Event: The Extraordinary He II and N II Features
Humphreys, Roberta M.; Davidson, Kris; Mehner, Andrea +2 more
Eta Carinae’s spectroscopic events (periastron passages) in 2003, 2009, and 2014 differed progressively. He ii λ4687 and nearby N ii multiplet 5 have special significance because they respond to very soft X-rays and the ionizing UV radiation field (EUV). Hubble Space Telescope (HST)/STIS observations in 2014 show dramatic increases in both feature…
End-of-life disposal of high elliptical orbit missions: The case of INTEGRAL
Armellin, Roberto; San-Juan, Juan F.; Lara, Martin
Nowadays there is international consensus that space activities must be managed to minimize debris generation and risk. The paper presents a method for the end-of-life (EoL) disposal of spacecraft in high elliptical orbits (HEO). The time evolution of HEO is strongly affected by Earth's oblateness and luni-solar perturbation, and this can cause in…