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Multi-fluid Model of a Streamer at Solar Minimum and Comparison with Observations
Giordano, Silvio; Ofman, Leon; Abbo, Lucia
We present the results of a time-dependent 2.5-dimensional three-fluid magnetohydrodynamic model of the coronal streamer belt, which is compared with the slow solar wind plasma parameters obtained in the extended corona by the UV spectroscopic data from the Ultraviolet Coronagraph Spectrometer (UVCS) on board SOHO during the past minimum of solar …
Structure and Dynamics of the 2009 July 22 Eclipse White-light Corona
Rušin, V.; Saniga, M.; Pasachoff, J. M. +2 more
The white-light corona (WLC) during the total solar eclipse of 2009 July 22 was observed by several teams in the Moon's shadow stretching from India and China across the Pacific Ocean with its many isolated islands. We present a comparison of the WLC as observed by eclipse teams located in China (Shanghai region) and on the Enewetak Atoll in the M…
Supersonic Downflows at the Umbra-Penumbra Boundary of Sunspots
Venkatakrishnan, P.; Mathew, Shibu K.; Louis, Rohan E. +1 more
High-resolution spectropolarimetric observations of three sunspots taken with Hinode demonstrate the existence of supersonic downflows at or close to the umbra-penumbra boundary which have not been reported before. These downflows are confined to large patches, usually encompassing bright penumbral filaments, and have lifetimes of more than 14 hr.…
Long-term Radiative Behavior Of SGR 1900+14
Kouveliotou, Chryssa; Göǧüş, Ersin; Güver, Tolga +2 more
The prolific magnetar SGR 1900+14 showed two outbursts in the last decade and has been closely monitored in the X-rays to track the changes in its radiative properties. We use archival Chandra and XMM-Newton observations of SGR 1900+14 to construct a history of its spectrum and persistent X-ray flux spanning a period of about seven years. We show …
Spectral Energy Distribution of z >~ 1 Type Ia Supernova Hosts in GOODS: Constraints on Evolutionary Delay and the Initial Mass Function
Chary, R. R.; Thomson, M. G.
We identify a sample of 22 host galaxies of Type Ia Supernovae (SNe Ia) at redshifts 0.95 < z < 1.8 discovered in the Hubble Space Telescope (HST) observations of the Great Observatories Origins Deep Survey (GOODS) fields. We measure the photometry of the hosts in Spitzer Space Telescope and ground-based imaging of the GOODS fields to provid…
Is Calvera a Gamma-Ray Pulsar?
Halpern, J. P.
Originally selected as a neutron star (NS) candidate in the ROSAT All-Sky Survey, 1RXS J141256.0+792204 ("Calvera") was discovered to be a 59 ms X-ray pulsar in a pair of XMM-Newton observations by Zane et al. Surprisingly, their claimed detection of this pulsar in Fermi γ-ray data requires no period derivative, severely restricting its dipole mag…
Study of the Poynting Flux in Active Region 10930 Using Data-driven Magnetohydrodynamic Simulation
Zhu, X. S.; He, H.; Wang, H. N. +1 more
Powerful solar flares are closely related to the evolution of magnetic field configuration on the photosphere. We choose the Poynting flux as a parameter in the study of magnetic field changes. We use time-dependent multidimensional MHD simulations around a flare occurrence to generate the results, with the temporal variation of the bottom boundar…
AKARI Near-infrared Spectroscopic Observations of Interstellar Ices in the Edge-on Starburst Galaxy NGC 253
Oyabu, Shinki; Onaka, Takashi; Yamagishi, Mitsuyoshi +4 more
We present the spatially resolved near-infrared (2.5-5.0 µm) spectra of the edge-on starburst galaxy NGC 253 obtained with the Infrared Camera on board AKARI. Near the center of the galaxy, we clearly detect the absorption features of interstellar ices (H2O: 3.05 µm, CO2: 4.27 µm, and XCN: 4.62 µm) and…
IRAS 15099-5856: Remarkable Mid-infrared Source with Prominent Crystalline Silicate Emission Embedded in the Supernova Remnant MSH15-52
Kohno, Kotaro; Onaka, Takashi; Yun, Min S. +18 more
We report new mid-infrared (MIR) observations of the remarkable object IRAS 15099-5856 using the space telescopes AKARI and Spitzer, which demonstrate the presence of prominent crystalline silicate emission in this bright source. IRAS 15099-5856 has a complex morphology with a bright central compact source (IRS1) surrounded by knots, spurs, and se…
Searching for Needles in Haystacks—Looking for Gamma-ray Burst γ-rays with the Fermi/LAT Detector
Zheng, W.; Pandey, S. B.; McKay, T. A. +1 more
Since the launch of the Fermi Gamma-ray Space Telescope on 2008 June 11, 55 gamma-ray bursts (GRBs) have been observed at coordinates that fall within 66° of the Fermi Large Area Telescope (LAT) boresight with precise localizations provided by the NASA Swift mission or other satellites. Imposing selection cuts to exclude low Galactic latitudes and…