Search Publications
From Voyager-IRIS to Cassini-CIRS: Interannual variability in Saturn’s stratosphere?
Fletcher, L. N.; Irwin, P. G. J.; Sinclair, J. A. +4 more
We present an intercomparison of Saturn’s stratosphere between Voyager 1-IRIS observations in 1980 and Cassini-CIRS observations in 2009 and 2010. Over a saturnian year (∼29.5 years) has now passed since the Voyager flybys of Saturn in 1980/1981. Cassini observations in 2009/2010 capture Saturn in the same season as Voyager observations (just afte…
Far-infrared Extinction Mapping of Infrared Dark Clouds
Tan, Jonathan C.; Lim, Wanggi
Progress in understanding star formation requires detailed observational constraints on the initial conditions, i.e., dense clumps and cores in giant molecular clouds that are on the verge of gravitational instability. Such structures have been studied by their extinction of near-infrared and, more recently, mid-infrared (MIR) background light. It…
The white dwarf cooling sequence of 47 Tucanae
Althaus, Leandro G.; Torres, Santiago; Miller Bertolami, Marcelo M. +1 more
Context. 47 Tucanae is one of the most interesting, well-observed, and theoretically studied globular clusters. This allows us to determine the reliability of our understanding of white dwarf cooling sequences, to compare different methods of determining its age, and to assess other important characteristics, such as its star formation history.
GS-TEC: the Gaia spectrophotometry transient events classifier
Wyrzykowski, Łukasz; Blagorodnova, Nadejda; Irwin, Mike +2 more
We present an algorithm for classifying the nearby transient objects detected by the Gaia satellite. The algorithm will use the low-resolution spectra from the blue and red spectrophotometers on board the satellite. Taking a Bayesian approach, we model the spectra using the newly constructed reference spectral library and literature-driven priors.…
Pulse phase-coherent timing and spectroscopy of CXOU J164710.2-45521 outbursts
Esposito, Paolo; Turolla, Roberto; Rea, Nanda +5 more
We present a long-term phase-coherent timing analysis and pulse-phase resolved spectroscopy for the two outbursts observed from the transient anomalous X-ray pulsar CXOU J164710.2-455216. For the first outburst we used 11 Chandra and XMM-Newton observations between 2006 September and 2009 August, the longest baseline yet for this source. We obtain…
No More Active Galactic Nuclei in Clumpy Disks Than in Smooth Galaxies at z ~ 2 in CANDELS/3D-HST
Barro, Guillermo; Bell, Eric F.; Ferguson, Henry C. +23 more
We use CANDELS imaging, 3D-HST spectroscopy, and Chandra X-ray data to investigate if active galactic nuclei (AGNs) are preferentially fueled by violent disk instabilities funneling gas into galaxy centers at 1.3 < z < 2.4. We select galaxies undergoing gravitational instabilities using the number of clumps and degree of patchiness as proxie…
Characterizing the Structure of Diffuse Emission in Hi-GAL Maps
Natoli, P.; Paladini, R.; Rygl, K. L. J. +18 more
We present a study of the structure of the Galactic interstellar medium (ISM) through the Δ-variance technique, related to the power spectrum and the fractal properties of infrared/submillimeter maps. Through this method, it is possible to provide quantitative parameters, which are useful for characterizing different morphological and physical con…
Formation and Decay of Rudimentary Penumbra around a Pore
Kitai, Reizaburo; Otsuji, Kenichi; Watanabe, Hiroko
We analyze the evolution of a pore in the active region NOAA 10940 using the data obtained by the Hinode satellite on 2007 February 3. The pore we analyzed showed the formation of a rudimentary penumbra structure, succeeded by an abrupt disappearance after about 5 hr. The pore had an approximate radius of 3.5 Mm and a total magnetic flux of 3.0 × …
Cassini ISS mutual event astrometry of the mid-sized Saturnian satellites 2005-2012
Cooper, N. J.; Lainey, V.; Murray, C. D. +3 more
Aims: We present astrometric observations of the Saturnian satellites Mimas, Enceladus, Tethys, Dione, and Rhea from Cassini Imaging Science Subsystem (ISS) narrow-angle camera (NAC) images. Image sequences were designed to observe mutual occultations between these satellites.
Methods: The positions of satellite centres were estimated by…
Discovery of Enhanced Radiative Recombination Continua of He-like Iron and Calcium from IC 443 and its Implications
Koyama, Katsuji; Uchida, Hiroyuki; Tsuru, Takeshi Go +3 more
We present deep observations of the Galactic supernova remnant IC 443 with the Suzaku X-ray satellite. We find prominent K-shell lines from iron and nickel, together with a triangle residual at 8-10 keV, which corresponds to the energy of the radiative recombination continuum (RRC) of He-like iron. In addition, the wavy residuals have been seen at…