Search Publications
A ground-to-exosphere Martian general circulation model: 1. Seasonal, diurnal, and solar cycle variation of thermospheric temperatures
Forget, F.; López-Valverde, M. A.; González-Galindo, F. +2 more
We present the extension to the thermosphere of a Martian general circulation model, the first able to self-consistently study the whole Martian atmosphere from the surface to the exosphere. We describe the parameterizations developed to include physical processes important for thermospheric altitudes. The results of a simulation covering 1 full M…
The dust condensation sequence in red supergiant stars
Eriksson, K.; Hony, S.; Decin, L. +3 more
Context: Red supergiant (RSG) stars exhibit significant mass loss by means of a slow, dense wind. They are often considered to be the more massive counterparts of Asymptotic Giant Branch (AGB) stars. While AGB mass loss is related to their strong pulsations, the RSG are often only weakly variable. This raises the question of whether their wind-dri…
Spectral variability of ultraluminous X-ray sources
Poutanen, Juri; Kajava, Jari J. E.
We study spectral variability of 11 ultraluminous X-ray sources (ULX) using archived XMM-Newton and Chandra observations. We use three models to describe the observed spectra: a power law, a multicolour disc (MCD) and a combination of these two models. We find that seven ULXs show a correlation between the luminosity LX and the photon i…
The First Swift Ultraviolet/Optical Telescope GRB Afterglow Catalog
Cucchiara, A.; Brown, P. J.; Page, M. J. +21 more
We present the first Swift Ultraviolet/Optical Telescope (UVOT) gamma-ray burst (GRB) afterglow catalog. The catalog contains data from over 64,000 independent UVOT image observations of 229 GRBs first detected by Swift, the High Energy Transient Explorer 2 (HETE2), the International Gamma-Ray Astrophysics Laboratory (INTEGRAL), and the Interplane…
Broad Relativistic Iron Emission Line Observed in SAX J1808.4-3658
Altamirano, D.; Wijnands, R.; Miller, J. M. +4 more
During the 2008 September-October outburst of the accreting millisecond pulsar SAX J1808.4-3658, the source was observed by both Suzaku and XMM-Newton approximately 1 day apart. Spectral analysis reveals a broad relativistic Fe Kα emission line which is present in both data sets, as has recently been reported for other neutron star low-mass X-ray …
Probing The Intergalactic Medium-Galaxy Connection At z < 0.5. I. A Galaxy Survey In Qso Fields And A Galaxy-Absorber Cross-Correlation Study
Chen, Hsiao-Wen; Mulchaey, John S.
We present an imaging and spectroscopic survey of galaxies in fields around QSOs HE 0226-4110, PKS 0405-123, and PG 1216+069. The fields are selected to have ultraviolet echelle spectra available, which uncover 195 Lyα absorbers and 13 O VI absorbers along the three sightlines. We obtain robust redshifts for 1104 galaxies of rest-frame absolute ma…
Dynamics of Galactic Disks and Mergers at z ~ 1.6: Spatially Resolved Spectroscopy with Keck Laser Guide Star Adaptive Optics
Erb, Dawn K.; Shapley, Alice E.; Steidel, Charles C. +3 more
We present 0farcs2 resolution near-infrared integral field spectroscopy of Hα emission from six star-forming galaxies at z ~ 1.6 (a look-back time of ~9.6 Gyr). These observations were obtained with OSIRIS using the Keck Laser Guide Star Adaptive Optics system. All sources have a compact spatial extent of ~1'', with an average half-light radius of…
Variability Timescales in the M87 Jet: Signatures of E 2 Losses, Discovery of a Quasi Period in HST-1, and the Site of TeV Flaring
Cheung, C. C.; Stawarz, Łukasz; Harris, D. E. +2 more
We investigate the variability timescales in the jet of M87 with two goals. The first is to use the rise times and decay times in the radio, ultraviolet, and X-ray light curves of HST-1 to constrain the source size and the energy loss mechanisms affecting the relativistic electron distributions. HST-1 is the first jet knot clearly resolved from th…
Optical-to-X-ray emission in low-absorption AGN: results from the Swift-BAT 9-month catalogue
Fabian, A. C.; Mushotzky, R. F.; Winter, L. M. +1 more
We present simultaneous optical-to-X-ray spectral energy distributions (SEDs) from Swift's X-ray and UV-optical telescopes (XRTs and UVOTs) for a well-selected sample of 26 low-redshift (z < 0.1) active galactic nuclei (AGN) from the Swift/Burst Alert Telescope 9-month catalogue, the largest well-studied, hard X-ray-selected survey of local AGN…
The redshift and afterglow of the extremely energetic gamma-ray burst GRB 080916C
Cenko, S. B.; Greiner, J.; Berger, E. +22 more
Context: The detection of GeV photons from gamma-ray bursts (GRBs) has important consequences for the interpretation and modelling of these most-energetic cosmological explosions. The full exploitation of the high-energy measurements relies, however, on accurate knowledge of the distance to the events.
Aims: Here we report on the discovery of …