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Probing the Ionization Structure of the Narrow-Line Region in the Seyfert 1 Galaxy NGC 4151
Kraemer, S. B.; Crenshaw, D. M.; Schmitt, H. R.
We present a study of the distribution of [O III] λ5007 and [O II] λ3727 emission in the narrow-line region (NLR) of the Seyfert 1 galaxy NGC 4151. While the NLR of NGC 4151 exhibits an overall structure consistent with the unified model of Seyfert galaxies, narrowband [O III] and [O II] images obtained with the Wide Field and Planetary Camera 2 a…
In-flight performance and calibration of SPICAV SOIR onboard Venus Express
Montmessin, Franck; Bertaux, Jean-Loup; Korablev, Oleg +13 more
Solar occultation in the infrared, part of the Spectoscopy for Investigation of Characteristics of the Atmosphere of Venus (SPICAV) instrument onboard Venus Express, combines an echelle grating spectrometer with an acousto-optic tunable filter (AOTF). It performs solar occultation measurements in the IR region at high spectral resolution. The wave…
Relative age of interior layered deposits in southwest Candor Chasma based on high-resolution structural mapping
Kirk, Randolph L.; McEwen, Alfred S.; Okubo, Chris H. +1 more
High-resolution topography generated from stereo HiRISE (High-Resolution Imaging Science Experiment) imagery reveals the meter-scale structure of interior layered deposits (ILD) in southwest Candor Chasma. This study seeks to determine the age of the local ILD relative to any normal faults that can be attributed to chasma formation. The study area…
Constraints on the Emission and Viewing Geometry of the Transient Anomalous X-Ray Pulsar XTE J1810-197
Gotthelf, E. V.; Perna, Rosalba
The temporal decay of the flux components of the transient anomalous X-ray pulsar XTE J1810-197 following its 2002 outburst presents a unique opportunity to probe the emission geometry of a magnetar. Toward this goal, we model the magnitude of the pulsar's modulation in narrow spectral bands over time. Following previous work, we assume that the p…
The Ascraeus Mons fan-shaped deposit: Volcano ice interactions and the climatic implications of cold-based tropical mountain glaciation
Head, James W.; Kadish, Seth J.; Marchant, David R. +1 more
Amazonian-aged fan-shaped deposits extending to the northwest of each of the Tharsis Montes in the Tharsis region on Mars have been interpreted to have originated from mass-wasting, volcanic, tectonic and/or glacial processes. We use new data from MRO, MGS, and Odyssey to characterize these deposits. Building on recent evidence for cold-based glac…
Discovery of a Young, Energetic 70.5 ms Pulsar Associated with the TeV Gamma-Ray Source HESS J1837-069
Gotthelf, E. V.; Halpern, J. P.
We report the discovery of 70.5 ms pulsations from the X-ray source AX J1838.0-0655 using the Rossi X-Ray Timing Explorer ( RXTE). PSR J1838-0655 is a rotation-powered pulsar with spin-down luminosity Ė = 5.5 × 1036 ergs s-1, characteristic age τc ≡ P/2dot P = 23 kyr, and surface dipole magnetic field strength B
First identification of mirror mode waves in Venus' magnetosheath?
Zhang, T. L.; Glassmeier, K. -H.; Baumjohann, W. +3 more
In this paper first time observations of mirror mode like structures in Venus' magnetosheath are presented. Using magnetometer data from the Venus Express spacecraft it is shown that in two regions in the Venusian magnetosheath strong compressional waves exist, which propagate nearly perpendicular to the ambient magnetic field. They are most likel…
An empirical model of Saturn's bow shock: Cassini observations of shock location and shape
Coates, A. J.; Dougherty, M. K.; Hospodarsky, G. B. +4 more
We present a new empirical model of Saturn's bow shock that utilizes observations from the Cassini spacecraft. Shock crossings are identified in magnetic field and plasma observations made by Cassini between June 2004 and August 2005. The Cassini crossings are then combined with the crossings made during the Saturn flybys of Pioneer 11, Voyager 1,…
A New Hubble Space Telescope Distance to NGC 1569: Starburst Properties and IC 342 Group Membership
Mack, Jennifer; Aloisi, Alessandra; van der Marel, Roeland P. +8 more
We present deep HST ACS/WFC photometry of the dwarf irregular galaxy NGC 1569, one of the closest and strongest nearby starburst galaxies. These data allow us, for the first time, to unequivocally detect the tip of the red giant branch and thereby determine the distance to NGC 1569. We find that this galaxy is 3.36 +/- 0.20 Mpc away, considerably …
XMM-Newton Observations of Radio Pulsars B0834+06 and B0826-34 and Implications for the Pulsar Inner Accelerator
Haberl, F.; Zhang, B.; Gil, J. +3 more
We report the X-ray observations of two radio pulsars with drifting subpulses, B0834+06 and B0826-34, using XMM-Newton. PSR B0834+06 was detected with a total of 70 counts from the three EPIC instruments over 50 ks exposure time. Its spectrum is best described as that of a blackbody (BB), with temperature Ts = (2.0+ 2.0-…