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Wind in the Solar Corona: Dynamics and Composition
Antonucci, Ester
The dynamics of the solar corona as observed during solar minimum with the Ultraviolet Coronagraph Spectrometer, UVCS, on SOHO is discussed. The large quiescent coronal streamers existing during this phase of the solar cycle are very likely composed by sub-streamers, formed by closed loops and separated by open field lines that are channelling a s…
Constraints on Galactic intermediate mass black holes
Rea, N.; Ferrara, A.; Mapelli, M.
Intermediate mass black holes (IMBHs; 101.3 to 105Msolar) are thought to form as relics of Population III stars or from the runaway collapse of stars in young clusters; their number and very existence are uncertain. We ran N-body simulations of Galactic IMBHs, modelling them as a halo population distributed accordi…
Mars Global MHD Predictions of Magnetic Connectivity Between the Dayside Ionosphere and the Magnetospheric Flanks
Liemohn, Michael W.; Barabash, Stas; Lundin, Rickard +7 more
Atmospheric photoelectrons have been observed well above the ionosphere of Mars by the ASPERA-3 ELS instrument on Mars Express. To systematically interpret these observations, field lines from two global MHD simulations were analyzed for connectivity to the dayside ionosphere (allowing photoelectron escape). It is found that there is a hollow cyli…
Chandra and XMM-Newton Observations of the Vela-like Pulsar B1046-58
Gaensler, B. M.; Gonzalez, M. E.; Kaspi, V. M. +1 more
We present results from Chandra and XMM-Newton observations of the radio pulsar B1046-58. A high-resolution spatial analysis reveals an asymmetric pulsar wind nebula (PWN), ~6''×11'' in size. The combined emission from the pulsar and its PWN is faint, with a best-fit power-law photon index of Γ=1.7+0.4-0.2
Why is the mass function of NGC 6218 flat?
Pulone, L.; Paresce, F.; de Marchi, G.
We have used the FORS-1 camera on the VLT to study the main sequence (MS) of the globular cluster NGC 6218 in the V and R bands. The observations cover an area of 3.4 arcmin × 3.4 arcmin around the cluster centre and probe the stellar population out to the cluster's half-mass radius (rh ≃ 2.2 arcmin). The colour-magnitude diagram (CMD) …
The Unusual X-Ray Spectrum of FU Orionis
Skinner, Stephen L.; Güdel, Manuel; Briggs, Kevin R.
FU Orionis objects (FUors) have undergone strong optical outbursts and are thought to be young low-mass stars accreting at high rates of up to M˙acc~10-4 Msolar yr-1. FUors have been extensively studied at optical and infrared wavelengths, but little is known about their X-ray properties. We have thus in…
Evidence of Orbital Motion in the Binary Brown Dwarf Kelu-1AB
Kulkarni, S. R.; Gelino, Christopher R.; Stephens, Denise C.
We have resolved Kelu-1 into a binary system with a separation of ~290 mas using the Laser Guide Star Adaptive Optics system on the Keck II telescope. We have also reanalyzed a 1998 HST observation of Kelu-1 and find that the observed PSF is best fit by a binary object separated by 45 mas. Observations at multiple epochs confirm that the two objec…
The sequestration of ethane on Titan in smog particles
Hunten, D. M.
Saturn's largest satellite, Titan, has a dense atmosphere of nitrogen with a few per cent of methane. At visible wavelengths its surface is hidden by dense orange-brown smog, which is produced in the stratosphere by photochemical reactions following the dissociation of methane by solar ultraviolet light. The most abundant of the products of these …
The super-soft source XMMU J052016.0-692505 in the LMC. A likely white dwarf Be/X-ray binary
Haberl, F.; Kahabka, P.; Filipović, M. D. +1 more
Aims.We report the discovery of the super-soft X-ray source XMMU J052016.0-692505 in the LMC with XMM-Newton.
Methods: .We analyse the EPIC spectra of XMMU J052016.0-692505 and study the likely optical counterpart LMCV2135.
Results: .Using an absorbed blackbody spectrum we derive a bolometric luminosity of ⪆ 1034 erg s-1
Detecting X-ray QPOs in active galaxies
Vaughan, Simon; Uttley, Philip
Since EXOSAT produced the first good quality X-ray light curves of Seyfert galaxies there have been several claims of quasi-periodic oscillations (QPOs). None of these have withstood repeated analyses and observations. We review some problems concerning the detection of QPOs.