Search Publications
A Strong Emission Line near 24.8 Å in the X-Ray Binary System MAXI J0556-332: Gravitational Redshift or Unusual Donor?
Raymond, John C.; Miller, Jon M.; Reynolds, Mark T. +1 more
We report the discovery of a strong emission line near 24.8 Å (0.5 keV) in the newly discovered X-ray binary system MAXI J0556-332 with the reflection grating spectrometer (RGS) on board the XMM-Newton observatory. The X-ray light curve morphology during these observations is complex and shows occasional dipping behavior. Here we present time- and…
Observational Evidences for the Existence of 17.4 keV Decaying Degenerate Sterile Neutrinos Near the Galactic Center
Chan, M. H.; Chu, M. -C.
We show that the existence of a degenerate halo of sterile neutrinos with rest mass of 17.4 keV near the Galactic center (GC) can account for both the excess 8.7 keV emission observed by the Suzaku mission and the power needed (1040 erg s-1) to maintain the high temperature of the hot gas (8 keV) near the GC. The required dec…
Time Variable Broad-line Emission in NGC 4203: Evidence for Stellar Contrails
Devereux, Nick
Dual epoch spectroscopy of the lenticular galaxy, NGC 4203, obtained with the Hubble Space Telescope has revealed that the double-peaked component of the broad Hα emission line is time variable, increasing by a factor of 2.2 in brightness between 1999 and 2010. Modeling the gas distribution responsible for the double-peaked profiles indicates that…
Regular Versus Diffusive Photospheric Flux Cancellation
Litvinenko, Yuri E.
Observations of photospheric flux cancellation on the Sun imply that cancellation can be a diffusive rather than regular process. A criterion is derived, which quantifies the parameter range in which diffusive photospheric cancellation should occur. Numerical estimates show that regular cancellation models should be expected to give a quantitative…
Contemporaneous XMM-Newton Investigation of a Giant X-ray Flare and Quiescent State from a Cool M-Class Dwarf in the Local Cavity
Gupta, A.; Williams, B.; Galeazzi, M.
We report the serendipitous detection of a giant X-ray flare from the source 2XMM J043527.2-144301 during an XMM-Newton observation of the high latitude molecular cloud MBM20. The source has not been previously studied at any wavelength. The X-ray flux increases by a factor of more than 52 from quiescent state to peak of flare. A 2MASS counterpart…
Detection of a Transient X-ray Absorption Line Intrinsic to the BL Lacertae Object H 2356-309
Canizares, Claude R.; Humphrey, Philip J.; Buote, David A. +1 more
Since the launch of the Einstein X-ray Observatory in the 1970s, a number of broad absorption features have been reported in the X-ray spectra of BL Lac objects. These features are often interpreted as arising from high-velocity outflows intrinsic to the BL Lac object, therefore providing important information about the inner environment around th…
Coronal Mass Ejection Dynamics Regarding Radial and Expansion Speeds
Dal Lago, Alisson; Rigozo, Nivaor R.; Nordeman, D. J. R.
A new technique for the detection of coronal mass ejection (CME) speeds using image processing was applied. This technique permits us to determine the CME dynamics: radial and expansion distances, velocities, and accelerations. The CME dynamics is determined by the selection of a radial direction in a given Large Angle and Spectroscopic Coronagrap…
X-Ray Spectroscopy of AS1101 with Chandra, XMM-Newton, and ROSAT: Bandpass Dependence of the Temperature Profile and Soft Excess Emission
Bonamente, Massimiliano; Nevalainen, Jukka
We present spatially resolved spectroscopy of the galaxy cluster AS1101, also known as Sèrsic 159-03, with Chandra, XMM-Newton, and ROSAT, and investigate the presence of soft X-ray excess emission above the contribution from the hot intracluster medium. In earlier papers we reported an extremely bright soft excess component that reached 100% of t…
Flares Producing Well-organized Post-flare Arcades (Slinkies) Have Early Precursors
Berger, T.; Frank, Z.; Ryutova, M. P. +1 more
Exploding loop systems producing X-ray flares often, but not always, bifurcate into a long-living, well-organized system of multi-threaded loop arcades resembling solenoidal slinkies. The physical conditions that cause or prevent this process are not known. To address this problem, we examined most of the major (X-class) flares that occurred durin…
Detection of Outflowing and Extraplanar Gas in Disks in an Assembling Galaxy Cluster at z = 0.37
Saintonge, Amélie; Tran, Kim-Vy H.; Gonzalez, Anthony H. +5 more
We detect ionized gas characteristics indicative of winds in three disk-dominated galaxies that are members of a super-group at z = 0.37 that will merge to form a Coma-mass cluster. All three galaxies are IR luminous (L IR > 4 × 1010 L ⊙, SFR > 8 M ⊙ yr-1) and lie outside the X-ray cores…