Search Publications
Solar Polar X-Ray Jets and Multiple Bright Points: Evidence for Sympathetic Activity
Romoli, Marco; Sterling, Alphonse C.; Pucci, Stefano +1 more
We present an analysis of X-ray bright points (BPs) and X-ray jets observed by Hinode/X-Ray Telescope on 2007 November 2-4, within the solar northern polar coronal hole. After selecting small subregions that include several BPs, we followed their brightness evolution over a time interval of a few hours, when several jets were observed. We find tha…
Low Ionization State Plasma in Coronal Mass Ejections
Raymond, John C.; Lee, Jin-Yi
The Ultraviolet Coronagraph Spectrometer (UVCS) on board the Solar and Heliospheric Observatory often observes low ionization state coronal mass ejection (CME) plasma at ultraviolet wavelengths. The CME plasmas are often detected in O VI (3 × 105 K), C III (8 × 104 K), Lyα, and Lyβ, with the low ionization plasma confined to …
Magnetic Flux Density Measured in Fast and Slow Solar Wind Streams
Balogh, A.; Erdős, G.
The radial component of the heliospheric magnetic field vector is used to estimate the open magnetic flux density of the Sun. This parameter has been calculated using observations from the Ulysses mission that covered heliolatitudes from 80°S to 80°N, from 1990 to 2009 and distances from 1 to 5.4 AU, the Advanced Composition Explorer mission at 1 …
Deflections of Fast Coronal Mass Ejections and the Properties of Associated Solar Energetic Particle Events
Gopalswamy, N.; Kahler, S. W.; Akiyama, S.
The onset times and peak intensities of solar energetic particle (SEP) events at Earth have long been thought to be influenced by the open magnetic fields of coronal holes (CHs). The original idea was that a CH lying between the solar SEP source region and the magnetic footpoint of the 1 AU observer would result in a delay in onset and/or a decrea…
Observation of High-speed Outflows in Coronal Loops Associated with Photospheric Magnetic Field Evolution
Liu, Y.; Su, J. T.; Liu, S. +2 more
Using SDO/AIA instruments, we provide an EUV observation of two adjacent loop strands (Loops 1 and 2) with one side of their footpoints rooted in the boundaries of active region (AR) NOAA 11158 and the other side in the quiet-Sun regions. The AR footpoints of Loop 1 were located in monopolar magnetic areas and those of Loop 2 in mixed polar areas …
The Merger History, Active Galactic Nucleus, and Dwarf Galaxies of Hickson Compact Group 59
Hornschemeier, A. E.; Brandt, W. N.; Konstantopoulos, I. S. +16 more
Compact group galaxies often appear unaffected by their unusually dense environment. Closer examination can, however, reveal the subtle, cumulative effects of multiple galaxy interactions. Hickson Compact Group (HCG) 59 is an excellent example of this situation. We present a photometric study of this group in the optical (Hubble Space Telescope), …
Multiband Optical Observation of the P/2010 A2 Dust Tail
Hasegawa, Sunao; Usui, Fumihiko; Yoshida, Michitoshi +6 more
An inner main-belt asteroid, P/2010 A2, was discovered on 2010 January 6. Based on its orbital elements, it is considered that the asteroid belongs to the Flora collisional family, where S-type asteroids are common, while showing a comet-like dust tail. Although analysis of images taken by the Hubble Space Telescope and Rosetta spacecraft suggeste…
Discovery of the Host Cluster for the Fundamental Cepheid Calibrator Zeta Geminorum
Gieren, W.; Balam, D.; Lane, D. +2 more
New and existing CORAVEL, UBVJHKs , HST, HIP/Tycho, ARO, KPNO, and DAO observations imply that the fundamental Cepheid calibrator ζ Gem is a cluster member. The following parameters were inferred for ζ Gem from cluster membership and are tied to new spectral classifications (DAO) established for 26 nearby stars (e.g., HD53588/B7.5IV, HD…
An In-depth Study of the Abundance Pattern in the Hot Interstellar Medium in NGC 4649
Loewenstein, Michael; Davis, David S.
We present our X-ray imaging spectroscopic analysis of data from deep Suzaku and XMM-Newton Observatory exposures of the Virgo Cluster elliptical galaxy NGC 4649 (M60), focusing on the abundance pattern in the hot interstellar medium (ISM). All measured elements show a radial decline in abundance, with the possible exception of O. We construct ste…
The Size Difference between Red and Blue Globular Clusters is not due to Projection Effects
Sills, Alison; Harris, William E.; Webb, Jeremy J.
Metal-rich (red) globular clusters in massive galaxies are, on average, smaller than metal-poor (blue) globular clusters. One of the possible explanations for this phenomenon is that the two populations of clusters have different spatial distributions. We test this idea by comparing clusters observed in unusually deep, high signal-to-noise images …