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The First Detection of [O IV] from an Ultraluminous X-Ray Source with Spitzer. I. Observational Results for Holmberg II ULX
Kallman, T. R.; Weaver, K. A.; Berghea, C. T. +1 more
We present the first Spitzer Infrared Spectrograph observations of the [O IV] 25.89 µm emission line detected from the ultraluminous X-ray source (ULX) in Holmberg II. This line is a well-established signature of high excitation, usually associated with active galactic nucleus (AGN). Its detection suggests that the ULX has a strong impact on…
X line distribution determined from earthward and tailward convective bursty flows in the central plasma sheet
Dunlop, M. W.; Baumjohann, W.; Reme, H. +5 more
With TC-1, Cluster, and Geotail observations, we statistically analyzed earthward and tailward convective bursty flows (CBFs) from 7 to 31 RE to understand the distribution of X lines in the magnetotail. We also analyzed the effect of the solar wind condition on the X lines with ACE satellite observations. The statistical results show t…
Excitation of electron cyclotron harmonic waves in the inner Saturn magnetosphere within local plasma injections
Gurnett, D. A.; Coates, A. J.; Hospodarsky, G. B. +6 more
Strong electron cyclotron harmonic (ECH) waves have been observed by Cassini associated with local plasma injection regions in the Saturnian magnetosphere. Using measured electron distributions from the Cassini plasma spectrometer, we calculated local growth rates and path-integrated wave gain of ECH waves inside an injection event using the HOTRA…
Late-stage water eruptions from Ascraeus Mons volcano, Mars: Implications for its structure and history
Williams, David A.; Muller, Jan-Peter; Murray, John B. +4 more
Ascraeus Mons was one of the first of the Martian volcanoes to be imaged by the High Resolution Stereo Camera (HRSC) experiment onboard the ESA Mars Express spacecraft. These images show much of the volcano at a higher resolution than previously, and details of its lava flows, sinuous rilles, flank vents and tectonic features indicate an unexpecte…
Modeling Evolving Coronal Loops with Observations from Stereo, Hinode, and Trace
Warren, Harry P.; Ugarte-Urra, Ignacio; Kim, David M. +1 more
The high densities, long lifetimes, and narrow emission measure distributions observed in coronal loops with apex temperatures near 1 MK are difficult to reconcile with physical models of the solar atmosphere. It has been proposed that the observed loops are actually composed of sub-resolution "threads" that have been heated impulsively and are co…
The Advanced Camera for Surveys Nearby Galaxy Survey Treasury. VI. The Ancient Star-forming Disk of NGC 404
Williams, Benjamin F.; Gilbert, Karoline M.; Dolphin, Andrew +5 more
We present HST/WFPC2 observations across the disk of the nearby isolated dwarf S0 galaxy NGC 404, which hosts an extended gas disk. The locations of our fields contain a roughly equal mixture of bulge and disk stars. All of our resolved stellar photometry reaches m F814W = 26 (M F814W = -1.4), which covers 2.5 mag of the …
Low-frequency magnetic field fluctuations in Venus' solar wind interaction region: Venus Express observations
Zhang, T. L.; Glassmeier, K. -H.; Narita, Y. +4 more
We investigate wave properties of low-frequency magnetic field fluctuations in Venus' solar wind interaction region based on the measurements made on board the Venus Express spacecraft. The orbit geometry is very suitable to investigate the fluctuations in Venus' low-altitude magnetosheath and mid-magnetotail and provides an opportunity for a comp…
Solar Cycle 23 in Coronal Bright Points
Karachik, Nina V.; Pevtsov, Alexei A.; Sattarov, Isroil +2 more
We describe an automatic routine to identify coronal bright points (CBPs) and apply this routine to SOHO/EIT observations taken in the 195 Å spectral range during solar cycle 23. We examine the total number of CBPs and its change in the course of this solar cycle. Unlike some other recent studies, we do find a modest ≈30% decrease in the number of…
Study of Hubble Space Telescope counterparts to Chandra X-ray sources in the globular cluster M 71
Heinke, C. O.; Edmonds, P. D.; Hsieh, B. C. +3 more
Aims: We report on archival Hubble Space Telescope (HST) observations of the globular cluster M 71 (NGC 6838).
Methods: These observations, covering the core of the globular cluster, were performed by the Advanced Camera for Surveys (ACS) and the Wide Field Planetary Camera 2 (WFPC2). Inside the half-mass radius (rh = 1farcm65…
Mapping the ionised gas around the luminous QSO HE 1029-1401: evidence for minor merger events?
Jahnke, K.; Husemann, B.; Sánchez, S. F. +4 more
We present VIMOS integral field spectroscopy of the brightest radio-quiet QSO on the southern sky HE 1029-1401 at a redshift of z = 0.086. Standard decomposition techniques for broad-band imaging are extended to integral field data in order to deblend the QSO and host emission. We perform a tentative analysis of the stellar continuum, finding a yo…