Search Publications
The Emission Measure of the Solar Lower Transition Region (2 × 104-2 × 105 K)
Landi, E.; Dammasch, I. E.; Feldman, U.
We analyze Solar Ultraviolet Measurements of Emitted Radiation (SUMER) spectra in the 750-790 Å wavelength range from 12 different solar regions on the disk to measure the thermal structure of the lower transition region (LTR). We considered four coronal hole (CH), four quiet Sun (QS), and four active region (AR) data sets observed by SUMER during…
Ellipsoidal Variable V1197 Orionis: Absolute Light-Velocity Analysis for Known Distance
Chochol, D.; Wilson, R. E.; Pribulla, T. +3 more
V1197 Orionis light curves from a long-term observing program for red giant binaries show ellipsoidal variation of small amplitude in the V and RC bands, although not clearly in U and B. Eclipses are not detected. All four bands show large irregular intrinsic variations, including fleeting quasi-periodicities identified by power spectra…
Renewed Activity from the X-Ray Transient SAXJ 1810.8-2609 with Integral
Fiocchi, M.; Ubertini, P.; Bazzano, A. +8 more
We report on the results of International Gamma-Ray Astrophysics Laboratory (INTEGRAL) observations of the neutron star low-mass X-ray binary SAX J1810.8-2609 during its latest active phase in 2007 August. The current outburst is the first one since 1998 and the derived luminosity is 1.1-2.6 ×1036 erg s-1 in the 20-100 keV en…
Formation Heights of Extreme Ultraviolet Lines in an Active Region Derived by Correlation of Doppler Velocity and Magnetic Field
Ding, M. D.; Guo, Y.; Wiegelmann, T. +1 more
We study the correlation heights, which indicate the formation height of Extreme Ultraviolet (EUV) lines in an active region using observations from the EUV Imaging Spectrometer and Solar Optical Telescope on board Hinode. The nonlinear force-free field optimization method is adopted to extrapolate the three-dimensional magnetic fields to higher l…
Discovery, Photometry, and Kinematics of Planetary Nebulae in M 82
Johnson, L. C.; Méndez, R. H.; Teodorescu, A. M.
Using an [O III] λ5007 on-band/off-band filter technique, we identify 109 planetary nebulae (PNe) candidates in the edge-on spiral galaxy M 82, using the FOCAS instrument at the 8.2 m Subaru Telescope. The use of ancillary high-resolution Hubble Space Telescope Advanced Camera for Surveys Hα imaging aided in confirming these candidates, helping to…
Characteristic Development of Magnetic Shear in a Flare-producing Sunspot Obtained from Vector Magnetic Field Measurements by Hinode
Magara, T.
One of the promising models for the initiation of a solar flare requires observation-based information at the solar surface where the energy released during a flare is injected in the way limited by a real environment. Hinode provides a time series of vector-field maps of the photospheric magnetic field in NOAA10930 that shows strong flaring activ…
Suzaku Observations of the Extreme MeV Blazar SWIFT J0746.3+2548
Takahashi, Tadayuki; Kataoka, Jun; Madejski, Greg +8 more
We report the Suzaku observations of the high luminosity blazar SWIFT J0746.3+2548 (J0746) conducted in 2005 November. This object, which, with z = 2.979, is the highest redshift source observed in the Suzaku Guaranteed Time Observer period, is likely to show high gamma-ray flux peaking in the MeV range. As a result of the good photon statistics a…
A Further Drop into Quiescence by the Eclipsing Neutron Star 4U 2129+47
Chakrabarty, Deepto; Nowak, Michael A.; Lin, Jinrong
The low-mass X-ray binary 4U 2129+47 was discovered during a previous X-ray outburst phase and was classified as an accretion disk corona source. A 1% delay between two mid-eclipse epochs measured ~22 days apart was reported from two XMM-Newton observations taken in 2005, providing support to the previous suggestion that 4U 2129+47 might be in a h…
Radio and X-Ray Properties of Submillimeter Galaxies in the A2125 Field
Menten, K. M.; Bertoldi, F.; Voss, H. +4 more
We present the radio and X-ray properties of 1.2 mm MAMBO source candidates in a 1600 arcmin2 field centered on the Abell 2125 galaxy cluster at z = 0.247. The brightest, nonsynchrotron millimeter source candidate in the field has a photometric redshift z = 3.93+1.11 -0.80 and is not detected in a 31 ks Chandra X-r…
Suzaku Spectroscopy of Vela Shrapnel B
Yamaguchi, H.; Katsuda, S.
We present the X-ray observation of Vela shrapnel B with the X-ray Imaging Spectrometer on board the Suzaku satellite. The shrapnel is one of several ejecta fragmentlike features protruding beyond the primary blast wave shock front of the Vela supernova remnant. The spectrum of shrapnel B is well represented by a single-temperature thin-thermal pl…