Search Publications
Discovery of a Multipolar Structure with an Equatorial disk in NGC 6072
Zhang, Yong; Kwok, Sun; Hsia, Chih-Hao +2 more
From near-infrared and molecular hydrogen imaging observations, we have discovered that the planetary nebula NGC 6072 has a multipolar structure with a prominent equatorial ring. We have modeled the object by a double bipolar system, each with an equatorial ring and a pair of bipolar lobes. The bipolar axes of the two systems are estimated to be s…
The X-ray Power Spectral Density Function of the Seyfert Active Galactic Nucleus NGC 7469
Markowitz, A.
We present the broadband X-ray power spectral density (PSD) function of the X-ray-luminous Seyfert 1.2 NGC 7469, measured from Rossi X-ray Timing Explorer monitoring data and two XMM-Newton observations. We find significant evidence for a turnover in the 2-10 keV PSD at a temporal frequency of 2.0+3.0 -0.8 × 10-6 H…
Multi-wavelength simulations of atmospheric radiation from Io with a 3-D spherical-shell backward Monte Carlo radiative transfer model
Trafton, Laurence M.; Gratiy, Sergey L.; Walker, Andrew C. +4 more
Conflicting observations regarding the dominance of either sublimation or volcanism as the source of the atmosphere on Io and disparate reports on the extent of its spatial distribution and the absolute column abundance invite the development of detailed computational models capable of improving our understanding of Io's unique atmospheric structu…
Energetic electrons in the exterior cusp: identifying the source
Chen, J.; Fritz, T. A.; Walsh, B. M. +1 more
A case study is presented to test the role several different sources may play in populating the exterior cusp with energetic (E>40 keV) electrons. The properties of the electrons measured in the exterior cusp are compared with the expected signatures of three sources in order to weigh the role each source may contribute in populating this regio…
In-depth studies of the NGC253 ULXs with XMM-Newton: remarkable variability in ULX1, and evidence for extended coronae
Barnard, R.
We examined the variability of three ultraluminous X-ray sources (ULXs) in the 2003, 110ks XMM-Newton observation of NGC253. Remarkably, we discovered ULX1 to be three times more variable than ULX2 in the 0.3-10 keV band, even though ULX2 is brighter. Indeed, ULX1 exhibits a power density spectrum that is consistent with the canonical high state o…
Project of the mission to Phobos
Zelenyi, L. M.; Zakharov, A. V.; Polischuk, G. M. +1 more
This article provides the main scientific objectives and characteristics of the Phobos-Soil project, intended to fly to the Martian satellite Phobos, deliver its soil samples to the Earth, as well as explore Phobos, Mars, and the Martian environment with onboard scientific instruments. We give the basic parameters of the ballistic scenario of the …
Escape of O+ through the distant tail plasma sheet
Sauvaud, J. -A.; Wurz, P.; Bochsler, P. +13 more
In February 2007, the STEREO-B spacecraft encountered the magnetosheath, plasma sheet and plasma sheet boundary layer from about 200 RE to 300 RE downtail. This time period was during solar minimum, and there was no storm activity during this month. Using data from the PLASTIC instrument, we find that even during quiet times,…
New Cassini RADAR results for Saturn’s icy satellites
Lorenz, R. D.; Ostro, S. J.; West, R. D. +13 more
Cassini radar tracks on Saturn's icy satellites through the end of the Prime Mission in 2008 have increased the number of radar albedo estimates from 10 ( Ostro et al., 2006) to 73. The measurements sample diverse subradar locations (and for Dione, Rhea, and Iapetus almost always use beamwidths less than half the target angular diameters), thereby…
General relativistic models of the X-ray spectral variability of MCG-6-30-15
Niedźwiecki, A.; Miyakawa, T.
Context. The extremely relativistic Fe lines, detected from some active galactic nuclei (AGN), indicate that generation and reprocessing of the X-ray emission takes place in the immediate vicinity of the event horizon. Recently, general relativistic (GR) effects, in particular light bending which is very strong in that region, have been considered…
Detection of unidentified infrared bands in a Hα filament in the dwarf galaxy NGC 1569 with AKARI
Onaka, T.; Sakon, I.; Kaneda, H. +1 more
Context. We report the detection of unidentified infrared (UIR) bands in a filamentary structure associated with Hα emission in the starburst dwarf galaxy NGC 1569 based on imaging and spectroscopic observations of the AKARI satellite.
Aims: We investigate the processing and destruction of the UIR band carriers in an outflow from NGC 1569.