Search Publications
Dust Properties of Local Dust-obscured Galaxies with the Submillimeter Array
Hwang, Ho Seong; Andrews, Sean M.; Geller, Margaret J.
We report Submillimeter Array observations of the 880 µm dust continuum emission for four dust-obscured galaxies (DOGs) in the local universe. Two DOGs are clearly detected with S ν(880 µm) =10-13 mJy and S/N > 5, but the other two are not detected with 3σ upper limits of S ν(880 µm) =5-9 mJy. Including a…
The Fading of Two Transient Ultraluminous X-Ray Sources to below the Stellar Mass Eddington Limit
Soria, Roberto; Maccarone, Thomas J.; Raychaudhury, Somak +10 more
We report new detections of the two transient ultraluminous X-ray sources (ULXs) in NGC 5128 from an ongoing series of Chandra observations. Both sources have previously been observed Lx (2-3) × ~1039 erg s-1, at the lower end of the ULX luminosity range. The new observations allow us to study these sources in the …
X-Ray Spectral Cutoff and the Lack of Hard X-Ray Emission from Two Ultraluminous X-Ray Sources M81 X-6 and Holmberg IX X-1
Jithesh, V.; Misra, R.; Dewangan, G. C. +1 more
We present broadband X-ray spectral study of two ultraluminous X-ray sources (ULXs), M81 X-6 and Holmberg IX X-1, based on Suzaku and XMM-Newton observations. We perform joint broadband spectral analysis of the brightest sources in the field, i.e., the two ULXs and the active galactic nucleus (AGN) in M81, and demonstrate that the X-ray spectra of…
The Role of Pickup Ions on the Structure of the Venusian Bow Shock and its Implications for the Termination Shock
Zank, Gary P.; Zhang, Tielong; Wang, Shui +5 more
The recent crossing of the termination shock by Voyager 2 has demonstrated the important role of pickup ions (PUIs) in the physics of collisionless shocks. The Venus Express (VEX) spacecraft orbits Venus in a 24 hr elliptical orbit that crosses the bow shock twice a day. VEX provides a unique opportunity to investigate the role of PUIs on the stru…
Fe XII Stalks and the Origin of the Axial Field in Filament Channels
Stenborg, G.; Sheeley, N. R., Jr.; Wang, Y. -M.
Employing Fe XII images and line-of-sight magnetograms, we deduce the direction of the axial field in high-latitude filament channels from the orientation of the adjacent stalklike structures. Throughout the rising phase of the current solar cycle 24, filament channels poleward of latitude 30° overwhelmingly obeyed the hemispheric chirality rule, …
Suzaku/WAM and RHESSI Observations of Non-thermal Electrons in Solar Microflares
Krucker, Säm; Ohno, Masanori; Lin, Robert P. +1 more
We report on hard X-ray spectroscopy of solar microflares observed by the Wide-band All-sky Monitor (WAM), on board the Suzaku satellite, and by RHESSI. WAM transient data provide wide energy band (50 keV-5 MeV) spectra over a large field of view (~2π sr) with a time resolution of 1 s. WAM is attractive as a hard X-ray solar flare monitor due to i…
Highly Ionized Fe-K Absorption Line from Cygnus X-1 in the High/Soft State Observed with Suzaku
Done, C.; Gandhi, P.; Yamada, S. +7 more
We present observations of a transient He-like Fe Kα absorption line in Suzaku observations of the black hole binary Cygnus X-1 on 2011 October 5 near superior conjunction during the high/soft state, which enable us to map the full evolution from the start to the end of the episodic accretion phenomena or dips for the first time. We model the X-ra…
The Size, Structure, and Ionization of the Broad-line Region in NGC 3227
Devereux, Nick
Hubble Space Telescope spectroscopy of the Seyfert 1.5 galaxy, NGC 3227, confirms previous reports that the broad Hα emission line flux is time variable, decreasing by a modest ~11% between 1999 and 2000 in response to a corresponding ~37% decrease in the underlying continuum. Modeling the gas distribution responsible for the broad Hα, Hβ, and Hγ …
Intervals of Radial Interplanetary Magnetic Fields at 1 AU, Their Association with Rarefaction Regions, and Their Apparent Magnetic Foot Points at the Sun
Zurbuchen, Thomas H.; Schwadron, Nathan A.; Smith, Charles W. +4 more
We have examined 226 intervals of nearly radial interplanetary magnetic field orientations at 1 AU lasting in excess of 6 hr. They are found within rarefaction regions as are the previously reported high-latitude observations. We show that these rarefactions typically do not involve high-speed wind such as that seen by Ulysses at high latitudes du…
Herschel/HIFI Observations of a New Interstellar Water Maser: The 532-441 Transition at 620.701 GHz
Menten, Karl M.; Tolls, Volker; Neufeld, David A. +4 more
Using the Herschel Space Observatory's Heterodyne Instrument for the Far-Infrared, we have performed mapping observations of the 620.701 GHz 532-441 transition of ortho-H2O within a ~1.'5 × 1.'5 region encompassing the Kleinmann-Low nebula in Orion (Orion-KL), and pointed observations of that transition toward the …