Search Publications
Missions
Journals
Publication Years
Non-LTE line formation for heavy elements in four very metal-poor stars
Zhao, G.; Mashonkina, L.; Aoki, W. +6 more
Aims:Stellar parameters and abundances of Na, Mg, Al, K, Ca, Sr, Ba, and Eu are determined for four very metal-poor (VMP) stars (-2.15 ≥ [Fe/H] ≥ -2.66). For two of them, HD 84937 and HD 122563, the fraction of the odd isotopes of Ba derived for the first time.
Methods: Determination of an effective temperature, surface gravity, and element ab…
Formation of Solar Magnetic Flux Tubes with Kilogauss Field Strength Induced by Convective Instability
Tsuneta, Saku; Shimizu, Toshifumi; Lites, Bruce W. +11 more
Convective instability has been a mechanism used to explain the formation of solar photospheric flux tubes with kG field strength. However, the turbulence of the Earth's atmosphere has prevented ground-based observers from examining the hypothesis with precise polarimetric measurement on the subarcsecond scale flux tubes. Here we discuss observati…
The Hubble Space Telescope/Advanced Camera for Surveys Atlas of Protoplanetary Disks in the Great Orion Nebula
Robberto, M.; Ricci, L.; Soderblom, D. R.
We present the atlas of protoplanetary disks in the Orion Nebula based on the Wide Field Channel of the Advanced Camera for Surveys (ACS/WFC) images obtained for the Hubble Space Telescope (HST) Treasury Program on the Orion Nebula Cluster. The observations have been carried out in five photometric filters nearly equivalent to the standard B, V, H…
Processes and mechanisms governing the initiation and propagation of CMEs
Vršnak, B.
The most important observational characteristics of coronal mass ejections (CMEs) are summarized, emphasizing those aspects which are relevant for testing physical concepts employed to explain the CME take-off and propagation. In particular, the kinematics, scalings, and the CME-flare relationship are stressed. Special attention is paid to 3-dimen…
Circumnuclear Gas in Seyfert 1 Galaxies: Morphology, Kinematics, and Direct Measurement of Black Hole Masses
Malkan, Matthew A.; Hicks, Erin K. S.
The two-dimensional (2D) distribution and kinematics of the molecular, ionized, and highly ionized gas in the nuclear regions of Seyfert 1 galaxies have been measured using high spatial resolution (~0.09'') near-infrared spectroscopy from NIRSPEC with adaptive optics on the Keck telescope. Molecular hydrogen, H2, is detected in all nine…
A new activity phase of the blazar 3C 454.3 . Multifrequency observations by the WEBT and XMM-Newton in 2007-2008
Lee, C. -U.; Pian, E.; Lähteenmäki, A. +72 more
Aims: The Whole Earth Blazar Telescope (WEBT) consortium has been monitoring the blazar
Methods: We present and analyse the multifrequency results of the 2007-2008 observing season, including XMM-Newton observations and near…
The UV colours of high-redshift early-type galaxies: evidence for recent star formation and stellar mass assembly over the last 8 billion years
van Dokkum, P. G.; Gawiser, E.; Urry, C. M. +7 more
We combine deep optical and NIR (UBVRIzJK) photometry from the Multiwavelength Survey by Yale-Chile (MUSYC) with redshifts from the COMBO-17 survey to perform a large-scale study of the rest-frame ultraviolet (UV) properties of 674 high-redshift (0.5 < z < 1) early-type galaxies, drawn from the Extended Chandra Deep Field-South (E-CDFS). Gal…
A New Survey for Giant Arcs
Hennawi, Joseph F.; Strauss, Michael A.; Schneider, Donald P. +11 more
We report on the first results of an imaging survey to detect strong gravitational lensing targeting the richest clusters selected from the photometric data of the Sloan Digital Sky Survey (SDSS) with follow-up deep imaging observations from the Wisconsin-Indiana-Yale NOAO (WIYN) 3.5 m telescope and the University of Hawaii 88 inch telescope (UH88…
Multidimensional modelling of X-ray spectra for AGN accretion disc outflows
Turner, T. J.; Long, K. S.; Sim, S. A. +1 more
We use a multidimensional Monte Carlo code to compute X-ray spectra for a variety of active galactic nucleus (AGN) disc-wind outflow geometries. We focus on the formation of blueshifted absorption features in the Fe K band and show that line features similar to those which have been reported in observations are often produced for lines of sight th…
The cosmological properties of AGN in the XMM-Newton Hard Bright Survey
Page, M. J.; Carrera, F. J.; Caccianiga, A. +7 more
Aims: We investigate here the X-ray luminosity function (XLF) of absorbed (NH between 4 × 1021 and 1024 cm-2) and unabsorbed (NH < 4 × 1021 cm-2) AGN, the fraction of absorbed AGN as a function of LX (and z), the intrinsic NH distribution of the A…