Search Publications
Spectral and temporal properties of the supergiant fast X-ray transient IGR J18483-0311 observed by INTEGRAL
Santangelo, A.; Esposito, P.; Ducci, L. +4 more
Context. IGR J18483-0311 is a supergiant fast X-ray transient whose compact object is located in a wide (18.5 d) and eccentric (e ~ 0.4) orbit, which shows sporadic outbursts that reach X-ray luminosities of ~1036 erg s-1.
Aims: We investigated the timing properties of IGR J18483-0311 and studied the spectra during brigh…
Case study of a complex active-region filament eruption
Yan, X. L.; Xue, Z. K.; Kong, D. F. +2 more
Context. We investigated a solar active-region filament eruption associated with a C6.6 class flare and a coronal mass ejection (CME) in NOAA active region 08858 on 2000 February 9.
Aims: We aim to better understand the relationship between filament eruptions and the associated flares and CMEs.
Methods: Using BBSO, SOHO/EIT, and TRACE ob…
Studies of NGC 6720 with Calibrated HST/WFC3 Emission-line Filter Images. II. Physical Conditions
O'Dell, C. R.; Henney, W. J.; Ferland, G. J. +1 more
We have performed a detailed analysis of the electron temperature and density in the Ring Nebula using the calibrated Hubble Space Telescope WFC3 images described in the preceding paper. The electron temperature (T e) determined from [N II] and [O III] rises slightly and monotonically toward the central star. The observed equivalent wid…
Globular Cluster Scale Sizes in Giant Galaxies: The Case of M87 and the Role of Orbital Anisotropy and Tidal Filling
Sills, Alison; Harris, William E.; Webb, Jeremy J.
We present new Hubble Space Telescope imaging of the outer regions of M87 in order to study its globular cluster (GC) population out to large galactocentric distances. We discuss, particularly, the relationship between GC effective radii rh and projected galactocentric distance R gc. The observations suggest a shallow trend r…
Venus Express observations of ULF and ELF waves in the Venus ionosphere: Wave properties and sources
Russell, C. T.; Wei, H. Y.; Zhang, T. L. +3 more
Electrical activity in a planetary atmosphere enables chemical reactions that are not possible under conditions of local thermodynamic equilibrium. In both the Venus and terrestrial atmospheres, lightning forms nitric oxide. Despite the existence of an inventory of NO at Venus like the Earth’s, and despite observations of the signals expected from…
Serendipitous Discovery of a Massive cD Galaxy at z = 1.096: Implications for the Early Formation and Late Evolution of cD Galaxies
Barro, Guillermo; Grogin, Norman A.; Hathi, Nimish P. +18 more
We have made a serendipitous discovery of a massive (~5 × 1011 M ⊙) cD galaxy at z = 1.096 in a candidate-rich cluster in the Hubble Ultra Deep Field (HUDF) area of GOODS-South. This brightest cluster galaxy (BCG) is the most distant cD galaxy confirmed to date. Ultra-deep HST/WFC3 images reveal an extended envelope starting …
The opposition effect in Saturn’s main rings as seen by Cassini ISS: 1. Morphology of phase functions and dependence on the local optical depth
Déau, Estelle; Dones, Luke; Charnoz, Sébastien +4 more
During the Prime mission (2004-2008), the Cassini cameras captured the opposition effect in Saturn’s main rings with a fine radial resolution at extremely small phase angles. Phase functions were extracted for 211 different radial locations in the main ring system (135 in the broadband clear filter of the Wide Angle Camera at 635 nm, 76 in four na…
Upper limits for PH3 and H2S in Titan's atmosphere from Cassini CIRS
Nixon, Conor A.; Irwin, Patrick G. J.; Teanby, Nicholas A. +1 more
We have searched for the presence of simple P and S-bearing molecules in Titan's atmosphere, by looking for the characteristic signatures of phosphine and hydrogen sulfide in infrared spectra obtained by Cassini CIRS. As a result we have placed the first upper limits on the stratospheric abundances, which are 1 ppb (PH3) and 330 ppb (H<…
Measuring chemical evolution and gravitational dependence of α using ultraviolet Fe v and Ni v transitions in white-dwarf spectra
Flambaum, V. V.; Berengut, J. C.; Ong, A.
In this paper, we present the details of the ab initio high-precision configuration interaction and many-body perturbation theory calculations that were used by Berengut [Phys. Rev. Lett.PRLTAO0031-900710.1103/PhysRevLett.111.010801 111, 010801 (2013)] to place limits on the dependence of the fine-structure constant, α, on the gravitational field …
Timescales on which Star Formation Affects the Neutral Interstellar Medium
Dolphin, Andrew E.; Williams, Benjamin F.; Ott, Jürgen +5 more
Turbulent neutral hydrogen (H I) line widths are often thought to be driven primarily by star formation (SF), but the timescale for converting SF energy to H I kinetic energy is unclear. As a complication, studies on the connection between H I line widths and SF in external galaxies often use broadband tracers for the SF rate, which must implicitl…