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Imaging X-Ray, Optical, and Infrared Observations of the Transient Anomalous X-Ray Pulsar XTE J1810-197
Gotthelf, E. V.; Halpern, J. P.; Buxton, M. +1 more
We report X-ray imaging, timing, and spectral studies of XTE J1810-197, a 5.54 s pulsar discovered by Ibrahim and coworkers in recent Rossi X-Ray Timing Explorer (RXTE) observations. In a set of short exposures with the High Resolution Camera on board the Chandra X-Ray Observatory, we detect a strongly modulated signal (55%+/-4% pulsed fraction) w…
Ultraviolet Emission from the Millisecond Pulsar J0437-4715
Pavlov, George G.; Kargaltsev, Oleg; Romani, Roger W.
We observed PSR J0437-4715 with the FUV-MAMA detector of the Space Telescope Imaging Spectrometer (STIS) to measure the pulsar's spectrum and pulsations. For the first time, UV emission from a millisecond pulsar has been detected. The measured flux, (2.0+/-0.2)×10-15 ergs s-1 cm-2 in the 1150-1700 Å range, correspo…
Spaceship Earth Observations of the Easter 2001 Solar Particle Event
Dröge, Wolfgang; Evenson, Paul; Ruffolo, David +5 more
The largest relativistic (~1 GeV) solar proton event of the current solar activity cycle occurred on Easter 2001 (April 15). This was the first such event to be observed by Spaceship Earth, an 11-station network of neutron monitors optimized for measuring the angular distribution of solar cosmic rays. We derive the particle density and anisotropy …
Evidence for Gradual External Reconnection before Explosive Eruption of a Solar Filament
Moore, Ronald L.; Sterling, Alphonse C.
We observe a slowly evolving quiet-region solar eruption of 1999 April 18, using extreme-ultraviolet (EUV) images from the EUV Imaging Telescope (EIT) on the Solar and Heliospheric Observatory (SOHO) and soft X-ray images from the Soft X-ray Telescope (SXT) on Yohkoh. Using difference images, in which an early image is subtracted from later images…
Bright Points in the Internetwork Quiet Sun
Muller, R.; Márquez, I.; Sánchez Almeida, J. +2 more
High-resolution G-band images of the interior of a supergranulation cell show ubiquitous bright points (BPs; some 0.3 BPs per Mm2). They are located in intergranular lanes and often form chains of elongated blobs whose smallest dimension is at the resolution limit (135 km on the Sun). Most of them live for a few minutes, having peak int…
Extreme-Ultraviolet and X-Ray Spectroscopy of a Solar Flare Loop Observed at High Time Resolution: A Case Study in Chromospheric Evaporation
Phillips, Kenneth J. H.; Brosius, Jeffrey W.
We present extreme-ultraviolet (EUV) and X-ray light curves and Doppler velocity measurements for a GOES class M2 solar flare observed in NOAA Active Region 9433 on 2001 April 24 at high time resolution with the Coronal Diagnostic Spectrometer (CDS) on board the Solar and Heliospheric Observatory (SOHO) satellite (9.83 s) and the Bragg Crystal Spe…
Two New Low Galactic D/H Measurements from the Far Ultraviolet Spectroscopic Explorer
Blair, William P.; Wood, Brian E.; Linsky, Jeffrey L. +3 more
We analyze interstellar absorption observed toward two subdwarf O stars, JL 9 and LS 1274, using spectra taken by the Far Ultraviolet Spectroscopic Explorer (FUSE). Column densities are measured for many atomic and molecular species (H I, D I, C I, N I, O I, P II, Ar I, Fe II, and H2), but our main focus is on measuring the D/H ratios f…
Ring-Diagram Analysis of the Structure of Solar Active Regions
Basu, Sarbani; Antia, H. M.; Bogart, Richard S.
We measure differences in structure between active and quiet regions of the Sun using the frequencies of high-degree modes determined from ring-diagram analyses. We find that both the speed of sound and the adiabatic index Γ1 differ in active regions as compared with quiet regions. In the immediate subsurface layers, the sound speed is …
Three Lyα Emitters at z ~ 6: Early GMOS/Gemini Data from the GLARE Project
Bunker, Andrew J.; Glazebrook, Karl; McCarthy, Patrick J. +14 more
We report spectroscopic detection of three z~6 Lyα-emitting galaxies, in the vicinity of the Hubble Ultra Deep Field, from the early data of the Gemini Lyman Alpha at Reionisation Era (GLARE) project. Two objects, GLARE 3001 (z=5.79) and GLARE 3011 (z=5.94), are new detections and are fainter in z' (z'AB=26.37 and …
The Far-Infrared Spectrum of Arp 220
Cernicharo, José; Smith, Howard A.; González-Alfonso, Eduardo +1 more
Infrared Space Observatory Long Wavelength Spectrometer grating observations of the ultraluminous infrared galaxy Arp 220 shows absorption in molecular lines of OH, H2O, CH, NH, and NH3, as well as in the [O I] 63 µm line and emission in the [C II] 158 µm line. We have modeled the continuum and the emission/absorp…