Search Publications
Time Variation and Statistical Studies of Magnetic Helicity Injection in Solar Magnetic Regions
Sakurai, T.; Yamamoto, Tetsuya T.
In this study, we analyzed the helicity injection in solar active regions statistically with the method proposed by Kusano et al. We investigated the variation in helicity injection as an active region evolves and the statistical distribution of helicity injection against the magnetic flux (Φ) and the latitude. The temporal evolution of active reg…
A New XMM-Newton Long Look of the Low-Luminosity Active Galactic Nucleus NGC 3226
Rothschild, R. E.; Markowitz, A.; Binder, B.
We present the results of a 99 ks XMM-Newton observation of NGC 3226, a low-luminosity active galactic nucleus. The long exposure has enabled us to critically test several models for the form of the 0.3-10 keV spectrum. We find the 0.3-10 keV spectrum is best fitted by a partial-covering model, consisting of a power-law continuum (Γ ≈ 1.87) absorb…
Detection of the Second Eclipsing High-Mass X-Ray Binary in M 33
Williams, Benjamin F.; Haberl, Frank; Mazeh, Tsevi +7 more
Chandra data of the X-ray source [PMH2004] 47 were obtained in the ACIS Survey of M 33 (ChASeM33) in 2006. During one of the observations, the source varied from a high state to a low state and back, in two other observations it varied from a low state to respectively intermediate states. These transitions are interpreted as eclipse ingresses and …
Unidentified Features in the Ultraviolet Spectrum of X Per
Snow, Theodore P.; Destree, Joshua D.
High-resolution ultraviolet spectra from the Space Telescope Imaging Spectrograph (STIS) were used to search for unidentified interstellar absorption features in the well studied sight line toward X Per (HD 24534). The significance of features detected was determined from Gaussian fits to the data, as well as the features' persistence in multiple …
Studying Large- and Small-Scale Environments of Ultraviolet Luminous Galaxies
Koekemoer, Anton M.; Madore, Barry F.; Ilbert, Olivier +24 more
Studying the environments of 0.4 < z < 1.2 ultraviolet (UV)-selected galaxies, as examples of extreme star-forming galaxies (with star formation rates (SFRs) in the range of 3-30 M sun yr-1), we explore the relationship between high rates of star formation, host halo mass, and pair fractions. We study the large- and sma…
Ages of M33 Star Clusters Based on the Hubble Space Telescope/WFPC2 Photometry
Lee, Myung Gyoon; Park, Hong Soo; Park, Won-Kee
We present a result of age estimation for star clusters in M33. We obtain color-magnitude diagrams (CMDs) of resolved stars in 242 star clusters from the Hubble Space Telescope/Wide Field Planetary Camera 2 images. We estimate ages of 100 star clusters among these, by fitting the Padova theoretical isochrones to the observational CMDs. Age distrib…
Contribution of Unresolved Point Sources to the Diffuse X-ray Background Below 1 keV
Gupta, A.; Galeazzi, M.
We present here the analysis of X-ray point sources detected in several observations available in the XMM-Newton public archive. We focused, in particular, on energies below 1 keV, which are of particular relevance to the understanding of the diffuse X-ray background (DXB). The average field of all the exposures is 0.09 deg-2. We reache…
SCUBA Observations of Early-Type Galaxies
Fich, Michel; Savoy, Jonathan; Welch, Gary A.
We present SCUBA observations of the emission of 23 E and S0 galaxies at wavelengths of 850 and 450 µm. Four galaxies are detected at 850 µm with signal-to-noise ratios above 3.0, and an additional galaxy, NGC 6524, is detected at both 850 and 450 µm. We use the SCUBA data with published optical and IRAS photometry to construct s…
Near-Simultaneous Observations of X-Ray Plasma Ejection, Coronal Mass Ejection, and Type II Radio Burst
Cho, K. -S.; Moon, Y. -J.; Kim, Yeon-Han +2 more
We report the first simultaneous observation of X-ray plasma ejection (XPE), coronal mass ejection (CME), and type II solar radio burst on 1999 October 26. First, an XPE was observed from 21:12 UT to 21:24 UT in the Yohkoh SXT field of view (1.1 to 1.4 R sun). The XPE was accelerated with a speed range from 190 to 410 km s-1 …
Constraining Dust and Color Variations of High-z SNe Using NICMOS on the Hubble Space Telescope
Panagia, N.; Lidman, C.; Nugent, P. E. +24 more
We present data from the Supernova Cosmology Project for five high redshift Type Ia supernovae (SNe Ia) that were obtained using the NICMOS infrared camera on the Hubble Space Telescope. We add two SNe from this sample to a rest-frame I-band Hubble diagram, doubling the number of high redshift supernovae on this diagram. This I-band Hubble diagram…