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Modeling Evolving Coronal Loops with Observations from Stereo, Hinode, and Trace
Warren, Harry P.; Ugarte-Urra, Ignacio; Kim, David M. +1 more
The high densities, long lifetimes, and narrow emission measure distributions observed in coronal loops with apex temperatures near 1 MK are difficult to reconcile with physical models of the solar atmosphere. It has been proposed that the observed loops are actually composed of sub-resolution "threads" that have been heated impulsively and are co…
The Advanced Camera for Surveys Nearby Galaxy Survey Treasury. VI. The Ancient Star-forming Disk of NGC 404
Williams, Benjamin F.; Gilbert, Karoline M.; Dolphin, Andrew +5 more
We present HST/WFPC2 observations across the disk of the nearby isolated dwarf S0 galaxy NGC 404, which hosts an extended gas disk. The locations of our fields contain a roughly equal mixture of bulge and disk stars. All of our resolved stellar photometry reaches m F814W = 26 (M F814W = -1.4), which covers 2.5 mag of the …
Using the 1.6 µm Bump to Study Rest-frame Near-infrared-selected Galaxies at Redshift 2
Sawicki, Marcin; Sorba, Robert
We explore the feasibility and limitations of using the 1.6 µm bump as a photometric redshift indicator and selection technique, and use it to study the rest-frame H-band galaxy luminosity and stellar mass functions (SMFs) at redshift z ~ 2. We use publicly available Spitzer/IRAC images in the GOODS fields and find that color selection in th…
The Abundance Pattern in the Hot ISM of NGC 4472: Insights and Anomalies
Loewenstein, Michael; Davis, David S.
Important clues to the chemical and dynamical history of elliptical galaxies are encoded in the abundances of heavy elements in the X-ray emitting plasma. We derive the hot interstellar medium abundance pattern in inner (0-2.3 Re ) and outer (2.3-4.6Re ) regions of NGC 4472 from analysis of Suzaku spectra, supported by analys…
Demonstrations that the Solar Wind is Not Accelerated By Waves or Turbulence
Roberts, D. Aaron
The present work uses observations and theoretical considerations to provide both qualitative and quantitative arguments that hydromagnetic waves, whether turbulent or not, cannot produce the acceleration of the fast solar wind and the related heating of the open solar corona. Waves do exist, and can play a role in the differential heating and acc…
Long-term Spectral Variations of Ultraluminous X-ray Sources in the Interacting Galaxy Systems M 51 and NGC 4490/85
Tsujimoto, Masahiro; Ebisawa, Ken; Matsushita, Kyoko +2 more
Variable ultraluminous X-ray sources (ULXs), which are considered to be black hole binaries (BHBs), are known to show state transitions similar to Galactic BHBs. However, the relation between the ULX states and the Galactic BHB states is still unclear, primarily due to the less well-understood behaviors of ULXs in contrast to the Galactic BHBs. He…
Searching for Diffuse Nonthermal X-Rays from the Superbubbles N11 and N51D in the Large Magellanic Cloud
Yamaguchi, H.; Bamba, A.; Sawada, M.
We report on observations of the superbubbles (SBs) N11 and N51D in the Large Magellanic Cloud (LMC) with Suzaku and XMM-Newton. The interior of both SBs exhibits diffuse X-ray emission, which is well represented by thin thermal plasma models with a temperature of 0.2-0.3 keV. The presence of nonthermal emission, claimed in previous works, is much…
M31 Pixel Lensing Event OAB-N2: A Study of the Lens Proper Motion
Gould, A.; Nucita, A.; Mancini, L. +13 more
We present an updated analysis of the M31 pixel lensing candidate event OAB-N2 previously reported by Calchi Novati et al. Here we take advantage of new data both astrometrical and photometrical. For astrometry: using archival 4 m KPNO and Hubble Space Telescope/WFPC2 data we perform a detailed analysis of the event source whose result, although n…
Diffuse Far-UV Line Emission from the Low-redshift Lyman Break Galaxy Analog KISSR242
Leitherer, Claus; France, Kevin; Nell, Nicholas +1 more
We present new ultraviolet (UV) observations of the luminous compact blue galaxy KISSR242, obtained with the Hubble Space Telescope-Cosmic Origins Spectrograph (HST-COS). We identify multiple resolved sub-arcsecond near-UV sources within the COS aperture. The far-UV spectroscopic data show strong outflow absorption lines, consistent with feedback …
Dynamics of the Flaring Loop System of 2005 August 22 Observed in Microwaves and Hard X-rays
Melnikov, V. F.; Shibasaki, K.; Ji, H. +1 more
We studied the spatial dynamics of the flaring loop in the 2005 August 22 event using microwave (NoRH) and hard X-ray (RHESSI) observations together with complementary data from SOHO/MDI, SMART at Hida, SOHO/EIT, and TRACE. We have found that (1) the pre-flare morphology of the active region exhibits a strongly sheared arcade seen in Hα and the J-…