Search Publications
Mode conversion between Alfvén and slow waves observed in the magnetotail by THEMIS
Zhang, T. L.; Glassmeier, K. -H.; Nakamura, R. +6 more
We present the direct spacecraft observations of wave mode conversion in the magnetotail for the first time. On February 28, 2008, the satellites P4 and P3 of THEMIS observe wave signals with a period of about 100 s in the magnetotail at about 11 RE. At the same time, geomagnetic activity is very quiet and there are no wave signals obse…
Solar Spectral Irradiance Variations in 240 - 1600 nm During the Recent Solar Cycles 21 - 23
Weber, M.; Pagaran, J.; Floyd, L. E. +2 more
Regular solar spectral irradiance (SSI) observations from space that simultaneously cover the UV, visible (vis), and the near-IR (NIR) spectral region began with SCIAMACHY aboard ENVISAT in August 2002. Up to now, these direct observations cover less than a decade. In order for these SSI measurements to be useful in assessing the role of the Sun i…
Supernovae without host galaxies?. Hypervelocity stars in foreign galaxies
Bomans, D. J.; Zinn, P. -C.; Grunden, P.
Context. Harvesting the SAI supernova catalog, the most complete list of supernovae (SNe) currently available, we search for SNe that apparently do not occur within a distinct host galaxy but lie a great distance (several arcmin) apart from the host galaxy given in the catalog or even show no sign of an identifiable galaxy in their direct vicinity…
Investigating the Nuclear Activity of Barred Spiral Galaxies: The Case of NGC 1672
Zezas, A.; Brandt, W. N.; Roberts, T. P. +7 more
We have performed an X-ray study of the nearby barred spiral galaxy NGC 1672, primarily to ascertain the effect of the bar on its nuclear activity. We use both Chandra and XMM-Newton observations to investigate its X-ray properties, together with supporting high-resolution optical imaging data from the Hubble Space Telescope (HST), infrared imagin…
The Abundances of Polyacetylenes Toward CRL618
Cernicharo, J.; Fonfría, J. P.; Richter, M. J. +1 more
We present a mid-infrared high spectral resolution spectrum of CRL618 in the frequency ranges 778-784 and 1227-1249 cm-1 (8.01-8.15 and 12.75-12.85 µm) taken with the Texas Echelon-cross-Echelle Spectrograph (TEXES) and the Infrared Telescope Facility (IRTF). We have identified more than 170 rovibrational lines arising from C…
Is CGCS 5926 a symbiotic X-ray binary?
Masetti, N.; Munari, U.; Osborne, J. P. +3 more
We report on multiwavelength (X-ray to optical) follow-up observations of the carbon star CGCS 5926. These were motivated by the fact that this star is positionally coincident with a faint X-ray emitting object belonging to the ROSAT catalog of sources, thus suggesting a possible symbiotic X-ray binary (SyXB) nature for it. Our spectrophotometric …
Multiwavelength campaign on Mrk 509. VII. Relative abundances of the warm absorber
Kaastra, J. S.; Kriss, G. A.; Arav, N. +14 more
Context. The study of abundances in the nucleus of active galaxies allows us to investigate the evolution of the abundance by comparing local and higher redshift galaxies. However, the methods used so far have substantial drawbacks or rather large uncertainties. Some of the measurements are at odds with the initial mass function derived from the o…
Observational Evidence of Changing Photospheric Vector Magnetic Fields Associated with Solar Flares
Zhang, H. Q.; Su, J. T.; Guo, J. +6 more
Recent observations have provided evidence that the solar photospheric magnetic fields could have rapid and permanent changes in both longitudinal and transverse components associated with major flares. As a result, the Lorentz force (LF) acting on the solar photosphere and solar interior could be perturbed, and the change of LF is always nearly i…
A multilayer model for thermal infrared emission of Saturn's rings. III: Thermal inertia inferred from Cassini CIRS
Spilker, Linda; Ohtsuki, Keiji; Morishima, Ryuji
The thermal inertia values of Saturn's main rings (the A, B, and C rings and the Cassini division) are derived by applying our thermal model to azimuthally scanned spectra taken by the Cassini Composite Infrared Spectrometer (CIRS). Model fits show the thermal inertia of ring particles to be 16, 13, 20, and 11 J m -2 K -1 s <…
The Last Eight-billion Years of Intergalactic Si IV Evolution
Prochaska, J. Xavier; Chen, Hsiao-Wen; Thom, Christopher +1 more
We identified 24 Si IV absorption systems with z <~ 1 from a blind survey of 49 low-redshift quasars with archival Hubble Space Telescope ultraviolet spectra. We relied solely on the characteristic wavelength separation of the doublet to automatically detect candidates. After visual inspection, we defined a sample of 20 definite (group G = 1) a…