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Radio and X-Ray Signatures of Magnetic Reconnection behind an Ejected Flux Rope
Pick, M.; Krucker, S.; Démoulin, P. +2 more
We present a detailed study of a complex solar event observed on 2002 June 2. Joint imaging EUV, X-ray, and multiwavelength radio observations allow us to trace the development of the magnetic structure involved in this solar event up to a radial distance of the order of 2 Rsolar. The event involves type II, III, and IV bursts. The type…
Limits from the Hubble Space Telescope on a Point Source in SN 1987A
Filippenko, Alexei V.; Garnavich, Peter; Fransson, Claes +16 more
We observed supernova 1987A (SN 1987A) with the Space Telescope Imaging Spectrograph (STIS) on the Hubble Space Telescope (HST) in 1999 September and again with the Advanced Camera for Surveys (ACS) on the HST in 2003 November. Our spectral observations cover ultraviolet (UV) and optical wavelengths from 1140 to 10266 Å, and our imaging observatio…
Three-dimensional Structure of Coronal Mass Ejections from LASCO Polarization Measurements
Wang, Dennis; Dere, Kenneth P.; Howard, Russell
The three-dimensional structure of a coronal mass ejection (CME) is essential information for understanding the process by which they are ejected from the Sun. Coronagraphic measurements readily provide information on the structure of CMEs in the plane of the sky. It has been known for some time that polarization measurements can provide informati…
Variability of Fe II Emission Features in the Seyfert 1 Galaxy NGC 5548
Peterson, Bradley M.; Vestergaard, Marianne
We study the low-contrast Fe II emission blends in the ultraviolet (1250-2200 Å) and optical (4000-6000 Å) spectra of the Seyfert 1 galaxy NGC 5548 and show that these features vary in flux and that these variations are correlated with those of the optical continuum. The amplitude of variability of the optical Fe II emission is 50%-75% that of Hβ,…
Reevaluation of the Magnetic Structure and Evolution Associated with the Bastille Day Flare on 2000 July 14
Zhang, Hongqi; Liu, Chang; Wang, Haimin +1 more
The Bastille Day flare on 2000 July 14 was well observed by several space- and ground-based observatories and studied extensively by many researchers. Recently, we discovered that a large fraction of X-class flares are associated with a very interesting evolutionary pattern in δ sunspots: part of the outer δ spot structure decays rapidly after maj…
XMM-Newton Observation of an X-Ray Trail between the Spiral Galaxy NGC 6872 and the Central Elliptical Galaxy NGC 6876 in the Pavo Group
Jones, Christine; Forman, William R.; Nulsen, Paul +2 more
We present XMM-Newton observations of a trail of enhanced X-ray emission extending along the full 8.7 arcmin ×4' region between the large spiral galaxy NGC 6872 and the dominant elliptical galaxy NGC 6876 in the Pavo group, the first known X-ray trail associated with a spiral galaxy in a poor galaxy group and, with a projected length of…
An XMM-Newton Observation of the Drifting Pulsar B0943+10
Pavlov, George G.; Zhang, Bing; Sanwal, Divas
Radio pulsar subpulse drifting has been interpreted as rotation of subbeams (sparks) of pair plasma produced by intermittent breakdowns of an inner vacuum gap above the pulsar polar cap. This model also predicts strong thermal X-ray emission from the polar cap caused by inflowing particles created in spark discharges. We have observed the best-stu…
Space Telescope Imaging Spectrograph Ultraviolet Spectra of Large Magellanic Cloud Planetary Nebulae: A Study of Carbon Abundances and Stellar Evolution
Gilmore, Diane; Shaw, Richard A.; Stanghellini, Letizia
We acquired spectra of 24 LMC planetary nebulae (PNs) in the 1150-3000 Å range in order to determine carbon and other ionic abundances. The sample more than doubles the number of LMC PNs with high-quality UV spectra in this wavelength range and whose optical images are available in the Hubble Space Telescope archive. The Space Telescope Imaging Sp…
Rapid Dissipation of Primordial Gas from the AU Microscopii Debris Disk
Weinberger, Alycia J.; Redfield, Seth; Roberge, Aki +1 more
The disk around AU Microscopii, an M1 star in the β Pictoris moving group, is extraordinarily well suited for comparison with the β Pic debris disk (type A5 V). We use far-UV absorption spectroscopy of AU Mic to probe its edge-on disk for small amounts of H2, the primary constituent of gas giant planets. Our conservative upper limit on …
Rotating Molecular Gas Associated with a Silhouette Disk at the Center of the Radio Galaxy 3C 31
Kohno, K.; Nakanishi, K.; Okuda, T. +1 more
Aperture synthesis observations of 12CO(J=1-0) emissions of the radio galaxy 3C 31 (NGC 383) have been made using the Nobeyama Millimeter Array (NMA) and the RAINBOW interferometer (NMA plus the Nobeyama 45 m radio telescope). Our high-resolution (1.9"×1.4", or 640pc×470pc, at D=70 Mpc) 12CO image shows a circularly rotating …