Search Publications
Resonant Compton upscattering in anomalous X-ray pulsars
Baring, Matthew G.; Harding, Alice K.
A significant new development in the study of Anomalous X-ray Pulsars (AXPs) has been the recent discovery by INTEGRAL and RXTE of flat, hard X-ray components in three AXPs. These non-thermal spectral components differ dramatically from the steeper quasi-power-law tails seen in the classic X-ray band in these sources. A prime candidate mechanism f…
The Optical Extragalactic Background Light: Revisions and Further Comments
Bernstein, Rebecca A.
We revise the measurements in our previous work of foreground zodiacal light (ZL) and diffuse Galactic light (DGL) that were used to measure the extragalactic background light (EBL). These changes result in a decrease of 8 and an increase of 0.3 in units of 10-9 ergs s-1 cm-2 sr-1 Å-1 (``cgs''…
Swift and XMM-Newton Observations of the Extraordinary Gamma-Ray Burst 060729: More than 125 Days of X-Ray Afterglow
Sakamoto, Takanori; Cummings, Jay; Gronwall, Caryl +24 more
We report the results of the Swift and XMM-Newton observations of the Swift -discovered GRB 060729 (T90=115 s). The afterglow of this burst was exceptionally bright in X-rays as well as at UV/optical wavelengths, showing an unusually long slow decay phase (α=0.14+/-0.02), suggesting a larger energy injection phase at early times than in…
The luminosity function of high-redshift quasi-stellar objects. A combined analysis of GOODS and SDSS
Brandt, W. N.; Vanzella, E.; Grazian, A. +5 more
Aims:In this work the luminosity function of QSOs is measured in the redshift range 3.5<z<5.2 for the absolute magnitude interval -21<M145<-28. Determining the faint-end of the luminosity function at these redshifts provides important constraints on models of the joint evolution of galaxies and AGNs.
Methods: We have def…
Recent formation and evolution of northern Martian polar layered deposits as inferred from a Global Climate Model
Forget, F.; Montmessin, F.; Laskar, J. +1 more
We present a time-marching model which simulates the exchange of water ice between the Martian northern cap, the tropics, and a high-latitude surface reservoir. Net annual exchange rates of water and their sensitivity to variations in orbital/rotational parameters are examined using the Martian water cycle modeled by the LMD three-dimensional Glob…
GRB 061121: Broadband Spectral Evolution through the Prompt and Afterglow Phases of a Bright Burst
Troja, E.; Sakamoto, T.; Melandri, A. +33 more
Swift triggered on a precursor to the main burst of GRB 061121 (z=1.314), allowing observations to be made from the optical to gamma-ray bands. Many other telescopes, including Konus-Wind, XMM-Newton, ROTSE, and the Faulkes Telescope North, also observed the burst. The gamma-ray, X-ray, and UV/optical emission all showed a peak ~75 s after the tri…
Mineralogy of the Nili Fossae region with OMEGA/Mars Express data: 1. Ancient impact melt in the Isidis Basin and implications for the transition from the Noachian to Hesperian
Mangold, N.; Bibring, J. -P.; Langevin, Y. +6 more
The Nili Fossae region located on the northwestern quadrant of the Isidis Basin, Mars, displays superb exposures of bedrock outcrops that reveal mineralogy and composition of the crust. Previous work has shown that this region exhibits the largest exposures of olivine-dominated rock units on Mars. Visible-infrared imaging spectrometer data acquire…
Sun-to-thermosphere simulation of the 28-30 October 2003 storm with the Space Weather Modeling Framework
Roussev, Ilia I.; Sokolov, Igor V.; Gombosi, Tamas I. +4 more
In late October and early November 2003 a series of some of the most powerful solar eruptions ever registered shook the heliosphere. These "Halloween storms" damaged 28 satellites, knocking two out of commission, diverted airplane routes, and caused power failures in Sweden, among other problems. This paper presents a 4-day end-to-end simulation o…
Observations of the south seasonal cap of Mars during recession in 2004-2006 by the OMEGA visible/near-infrared imaging spectrometer on board Mars Express
Bibring, J. -P.; Gondet, B.; Langevin, Y. +5 more
The OMEGA visible/near-infrared imaging spectrometer on board Mars Express has observed the southern seasonal cap in late 2004 and 2005 and then in the summer of 2006. These observations extended from the period of maximum extension, close to the southern winter solstice, to the end of the recession at Ls 325°. The spectral range and sp…
Signatures of synchrotron emission and of electron acceleration in the X-ray spectra of Mrk 421
Tramacere, A.; Massaro, F.; Cavaliere, A.
Context: BL Lac objects undergo strong flux variations involving considerable changes in their spectral shapes. We specifically investigate the X-ray spectral evolution of Mrk 421 over a time span of about nine years.
Aims: We aim at statistically describing and physically understanding the large spectral changes in X rays observed in Mrk 421 …