Search Publications
Vector Magnetic Fields of Solar Granulation
Wang, Jingxiu; Jin, Chunlan; Zhao, Meng
Observations of the quiet Sun from the Solar Optical Telescope/Spectro-Polarimeter aboard the Hinode spacecraft reveal the magnetic characteristics of the solar photosphere. By making use of the deep-mode observations of three quiet regions, we have statistically studied the vector magnetic fields of solar granulation. More than 2000 normal granul…
Star Formation History of the Small Magellanic Cloud: Six Hubble Space Telescope/Advanced Camera for Survey Fields
Da Costa, G. S.; Anderson, J.; Cignoni, M. +9 more
We observed six fields of the Small Magellanic Cloud (SMC) with the Advanced Camera for Survey on board the Hubble Space Telescope in the F555W and F814W filters. These fields sample regions characterized by very different star and gas densities, and, possibly, by different evolutionary histories. We find that the SMC was already forming stars ~12…
Phase relation of oscillations near the planetary period of Saturn's auroral oval and the equatorial magnetospheric magnetic field
Nichols, J. D.; Cowley, S. W. H.; Provan, G.
Previous analyses of Hubble Space Telescope (HST) images of Saturn's southern auroras obtained during two campaigns, in January 2007 and February 2008, have revealed that the auroral oval oscillates at a period close to the planetary rotation period, with its center describing an elongated ellipse of semimajor axis ∼2° colatitude aligned along the…
Can the Composition of the Solar Corona Be Derived from Hinode/Extreme-Ultraviolet Imaging Spectrometer Spectra?
Doschek, G. A.; Warren, H. P.; Brown, C. M. +1 more
Elemental abundances appear to be the same everywhere in the photosphere, but in the solar corona they vary in different regions. Abundances in quiet Sun (closed) flux tubes are different from those in coronal hole (CH, open) magnetic field regions, and therefore abundance variations might possibly be used to determine locations of slow and fast s…
New Magellan Inamori Kyocera Echelle Observations of z < 1.5 sub-damped Lyman α systems
York, Donald G.; Kulkarni, Varsha P.; Lauroesch, James T. +3 more
The damped Lyman α (DLA) and sub-damped Lyman α (sub-DLA) systems seen in the spectra of quasi-stellar objects (QSOs) offer a unique way to study the interstellar medium (ISM) of high-redshift galaxies. In this paper, we report on new abundance determinations in a sample of 10 new systems, nine of the lesser studied sub-DLAs and one DLA along the …
The ultraluminous X-ray source population of NGC 4485/4490
Roberts, Timothy P.; Gladstone, Jeanette C.
We report the results of spectral and temporal variability studies of the ultraluminous X-ray sources (ULXs) contained within the interacting pair of galaxies NGC 4485/4490, combining Chandra and XMM-Newton observations. Each of the four separate observations provide at least modest quality spectra and light curves for each of the six previously i…
A Universal Decline Law of Classical Novae. IV. V838 Her (1991): A Very Massive White Dwarf
Cassatella, Angelo; Kato, Mariko; Hachisu, Izumi
We present a unified model of optical and ultraviolet (UV) light curves for one of the fastest classical novae, V838 Herculis (Nova Herculis 1991), and estimate its white dwarf (WD) mass. Based on an optically thick wind theory of nova outbursts, we model the optical light curves with free-free emission and the UV 1455 Å light curves with blackbod…
The dynamics of the giant radio galaxy 3C457
Hardcastle, M. J.; Croston, J. H.; Saikia, D. J. +1 more
We present multifrequency radio observations with the Giant Metrewave Radio Telescope and Very Large Array, and X-ray observations with the X-ray Multi-Mirror Mission (XMM-Newton) telescope of the giant radio source (GRS) 3C457. We have detected the core, lobes and the environment of the GRS in X-ray. We examine the relationships between the radio…
The absence of endogenic methane on Titan and its implications for the origin of atmospheric nitrogen
Desch, Steven J.; Glein, Christopher R.; Shock, Everett L.
We calculate the D/H ratio of CH 4 from serpentinization on Titan to determine whether Titan's atmospheric CH 4 was originally produced inside the giant satellite. This is done by performing equilibrium isotopic fractionation calculations in the CH 4-H 2O-H 2 system, with the assumption that t…
The diverse X-ray properties of four truly isolated elliptical galaxies: NGC 2954, NGC 6172, NGC 7052, and NGC 7785
Wolter, A.; Trinchieri, G.; Memola, E. +2 more
Aims: We investigate the X-ray properties of four isolated elliptical galaxies, selected from the Updated Zwicky Catalog according to strict isolation criteria. Isolated galaxies are not influenced by the group/cluster environment, and their X-ray emission can be studied independently of the often overwhelming contribution of the hot intergalactic…