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The X-Ray Structure and Spectrum of the Pulsar Wind Nebula Surrounding PSR B0540-69.3
Safi-Harb, S.; Holt, S. S.; Williams, R. M. +2 more
We present the first spatially resolved spectral study of an extragalactic pulsar wind nebula (PWN), that surrounding the 50 ms pulsar B0540-69.3 in the Large Magellanic Cloud, using the ACIS instrument on board the Chandra X-ray Observatory. The spectral properties of the PWN change at a radius of ~5", corresponding to a shell detected optically …
Elemental Abundances of Nearby Galaxies through High Signal-to-Noise Ratio XMM-Newton Observations of Ultraluminous X-Ray Sources
Reynolds, Christopher S.; Mushotzky, Richard F.; Winter, Lisa M.
In this paper we examined XMM-Newton EPIC spectra of 14 ultraluminous X-ray sources (ULXs) in addition to the XMM-Newton RGS spectra of two sources (Holmberg II X-1 and Holmberg IX X-1). We determined oxygen and iron abundances of the host galaxy's ISM using K-shell (O) and L-shell (Fe) X-ray photoionization edges toward these ULXs. We found that …
A Galaxy in Transition: Structure, Globular Clusters, and Distance of the Star-Forming S0 Galaxy NGC 1533 in Dorado
Meurer, Gerhardt R.; Blakeslee, John P.; Putman, Mary E. +1 more
We use two-band imaging data from the Advanced Camera for Surveys onboard the Hubble Space Telescope for a detailed study of NGC 1533, an SB0 galaxy in the Dorado group surrounded by a ring of H I. NGC 1533 appears to be completing a transition from late to early type: it is red, but not quite dead. Faint spiral structure becomes visible following…
GQ Lup B Visible and Near-Infrared Photometric Analysis
Macintosh, Bruce; Barman, Travis; Marois, Christian
We have reanalyzed archival HST and Subaru data of the recently discovered planetary mass companion (PMC) GQ Lup B. With these we produce the first R- and I-band photometry of the companion and fit a radius and effective temperature using detailed model atmospheres. We find an effective temperature of 2335+/-100 K, a radius of 0.38+/-0.05 Rso…
The Merger in Abell 576: A Line-of-Sight Bullet Cluster?
Bregman, Joel N.; Dupke, Renato A.; Mirabal, Nestor +1 more
Using a combination of Chandra and XMM-Newton observations, we confirmed the presence of a significant velocity gradient along the northeast-southwest direction in the intracluster gas of the cluster Abell 576. The results are consistent with a previous ASCA SIS analysis of this cluster. The error-weighted average over the ACIS-S3 and EPIC MOS1 an…
Initial Observations of Sunspot Oscillations Excited by Solar Flare
Kosovichev, A. G.; Sekii, T.
Observations of a large solar flare on 2006 December 13 using Solar Optical Telescope (SOT) on board the Hinode spacecraft revealed high-frequency oscillations excited by the flare in the sunspot chromosphere. These oscillations are observed in the region of strong magnetic field of the sunspot umbra and may provide a new diagnostic tool for probi…
The First Direct Detection of a Gravitational µ-Lens toward the Galactic Bulge
Kozłowski, S.; Mao, S.; Woźniak, P. R. +1 more
We present a direct detection of the gravitational lens that caused the microlensing event MACHO-95-BLG-37. This is the first fully resolved microlensing system involving a source in the Galactic bulge, and the second such system in general. The lens and source are clearly resolved in images taken with the High Resolution Channel of the Advanced C…
Very High Energy Observations of Gamma-Ray Burst Locations with the Whipple Telescope
Fegan, S. J.; Fortin, P.; Horan, D. +56 more
Gamma-ray burst (GRB) observations at very high energies (VHE; E>100 GeV) can impose tight constraints on some GRB emission models. Many GRB afterglow models predict a VHE component similar to that seen in blazars and plerions, in which the GRB spectral energy distribution has a double-peaked shape extending into the VHE regime. VHE emission co…
Hard X-Ray Intensity Distribution along Hα Ribbons
Liu, Chang; Jing, Ju; Wang, Haimin +2 more
Unusual ribbon-like hard X-ray sources were found with the RHESSI observation of a 2B/M8.0 flare on 2005 May 13. We use this unique observation to investigate the spatial distribution of the hard X-ray intensity along the ribbons and compare it with the local magnetic reconnection rate and energy release rate predicted by the standard magnetic rec…
Spectral Modeling of the High-Energy Emission of the Magnetar 4U 0142+614
Stella, L.; Rea, N.; Tramacere, A. +4 more
We present an empirical spectral modeling of the high-energy emission of the anomalous X-ray pulsar 4U 0142+614 based on simultaneous Swift and INTEGRAL observations from X- to γ-ray energies. We adopted models contained in the XSPEC analysis package, as well as models based on recent theoretical studies, and restricted ourselves to those combinat…