Search Publications
Plasma Motions and Heating by Magnetic Reconnection in a 2007 May 19 Flare
Harra, Louise K.; Hara, Hirohisa; Young, Peter R. +2 more
Based on scanning spectroscopic observations with the Hinode EUV imaging spectrometer, we have found a loop-top hot source, a fast jet nearby, and an inflow structure flowing to the hot source that appeared in the impulsive phase of a long-duration flare at the disk center on 2007 May 19. The hot source observed in Fe XXIII and Fe XXIV emission li…
The Discovery and Nature of the Optical Transient CSS100217:102913+404220
Drake, A. J.; Djorgovski, S. G.; Anderson, J. +32 more
We report on the discovery and observations of the extremely luminous optical transient CSS100217:102913+404220 (CSS100217 hereafter). Spectroscopic observations showed that this transient was coincident with a galaxy at redshift z = 0.147 and reached an apparent magnitude of V ~ 16.3. After correcting for foreground Galactic extinction we determi…
The Star-formation-rate-Density Relation at 0.6 < z < 0.9 and the Role of Star-forming Galaxies
Franx, Marijn; Kelson, Daniel D.; Illingworth, Garth D. +2 more
We study the star formation rates (SFRs) of galaxies as a function of local galaxy density at 0.6 < z < 0.9. We used a low-dispersion prism in IMACS on the 6.5 m Baade (Magellan I) telescope to obtain spectra and measured redshifts to a precision of σ z /(1 + z) ~ 1% for galaxies with z AB < 23.3 mag. We utilized a s…
AKARI Observation of the Fluctuation of the Near-infrared Background
Lee, H. M.; Jeong, W. -S.; Matsuhara, H. +6 more
We report a search for fluctuations of the sky brightness toward the north ecliptic pole with the Japanese infrared astronomical satellite AKARI, at 2.4, 3.2, and 4.1 µm. We obtained circular maps with 10' diameter fields of view, which clearly show a spatial structure on the scale of a few hundred arcseconds. A power spectrum analysis shows…
Diffuse Emission Measurement with the SPectrometer on INTEGRAL as an Indirect Probe of Cosmic-Ray Electrons and Positrons
Jourdain, Elisabeth; Roques, Jean-Pierre; Bouchet, Laurent +3 more
Significant advances have been made in the understanding of the diffuse Galactic hard X-ray continuum emission using data from the INTEGRAL observatory. The diffuse hard power-law component seen with the SPectrometer on INTEGRAL (SPI) has been identified with inverse-Compton emission from relativistic (GeV) electrons on the cosmic microwave backgr…
Molecular Gas in Young Debris Disks
Apai, D.; Pascucci, I.; Ábrahám, P. +7 more
Gas-rich primordial disks and tenuous gas-poor debris disks are usually considered as two distinct evolutionary phases of the circumstellar matter. Interestingly, the debris disk around the young main-sequence star 49 Ceti possesses a substantial amount of molecular gas and possibly represents the missing link between the two phases. Motivated to …
Observation of High-speed Outflow on Plume-like Structures of the Quiet Sun and Coronal Holes with Solar Dynamics Observatory/Atmospheric Imaging Assembly
He, Jiansen; Habbal, Shadia Rifai; McIntosh, Scott W. +1 more
Observations from the Atmospheric Imaging Assembly onboard the Solar Dynamics Observatory reveal ubiquitous episodic outflows (jets) with an average speed around 120 km s-1 at temperatures often exceeding a million degree in plume-like structures, rooted in magnetized regions of the quiet solar atmosphere. These outflows are not restric…
A Combined Low-radio Frequency/X-ray Study of Galaxy Groups. I. Giant Metrewave Radio Telescope Observations at 235 MHz AND 610 MHz
Raychaudhury, Somak; Jones, Christine; Clarke, Tracy E. +12 more
We present new Giant Metrewave Radio Telescope observations at 235 MHz and 610 MHz of 18 X-ray bright galaxy groups. These observations are part of an extended project, presented here and in future papers, which combines low-frequency radio and X-ray data to investigate the interaction between central active galactic nuclei (AGNs) and the intra-gr…
A Comparative Study of Confined and Eruptive Flares in NOAA AR 10720
Cheng, X.; Ding, M. D.; Zhang, J. +2 more
We investigate the distinct properties of two types of flares: eruptive flares associated with coronal mass ejections (CMEs) and confined flares without CMEs. Our study sample includes nine M- and X-class flares, all from the same active region (AR), six of which are confined and three others which are eruptive. The confined flares tend to be more…
Variations in the Axisymmetric Transport of Magnetic Elements on the Sun: 1996-2010
Hathaway, David H.; Rightmire, Lisa
We measure the axisymmetric transport of magnetic flux on the Sun by cross-correlating narrow strips of data from line-of-sight magnetograms obtained at a 96 minute cadence by the MDI instrument on the ESA/NASA SOHO spacecraft and then averaging the flow measurements over each synodic rotation of the Sun. Our measurements indicate that the axisymm…