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The soft X-ray counterpart of the newly discovered INTEGRAL source IGR J16195-4945
Mereghetti, S.; Sidoli, L.; Vercellone, S. +1 more
The INTEGRAL satellite, during its regular scanning observations of the Galactic plane, has discovered several new X-ray sources emitting above 20 keV. The nature of the great majority of them is still unknown. Here we report on the likely low energy counterpart, observed with ASCA in 1994 and 1997, of one of these sources, IGR J16195-4945. The AS…
The Ultraluminous X-Ray Source X-37 Is a Background Quasar in the Antennae Galaxies
Hayward, T. L.; Brandl, B. R.; Eikenberry, S. S. +8 more
In this Letter we report that a bright, X-ray source in the Antennae galaxies (NGC 4038/9), previously identified as an ultraluminous X-ray source (ULX), is in fact a background quasar. We identify an isolated infrared and optical counterpart within 0.3" +/- 0.5" of the X-ray source X-37. After acquiring an optical spectrum of its counterpart, we …
The Interaction of the Galactic Center Arches Cluster and the Thermal Filaments
Rubin, Robert H.; Colgan, Sean W. J.; Simpson, Janet P. +1 more
We present Infrared Space Observatory (ISO) measurements of the far-infrared (FIR) fine-structure lines [S IV] (10.5 µm), [S III] (33.5 µm), [O III] (51.8 and 88.4 µm), [N III] (57.3 µm), [N II] (121.9 µm), [O I] (63.2 and 145.5 µm), and [C II] (157.7 µm) at five positions on the thermal ``Arched'' Filamen…
The SDSS/XMM-Newton Quasar Sample. I. First Results
Elvis, Martin; Risaliti, Guido
We have searched in the XMM-Newton public archive for quasars in the Sloan Digital Sky Survey First Data Release and found 55 lying in the field of an XMM-Newton observation with exposure times >20 ks (as of 2004 August). The 35 quasars that yielded good X-ray spectra span redshifts from 0.5 to 2.5. The large collecting area of XMM-Newton allow…
A Deep Search with the Hubble Space Telescope for Late-Time Supernova Signatures in the Hosts of XRF 011030 and XRF 020427
Wood-Vasey, W. Michael; Ramirez-Ruiz, Enrico; Tanvir, Nial +16 more
X-ray flashes (XRFs) are, like gamma-ray bursts (GRBs), thought to signal the collapse of massive stars in distant galaxies. Many models posit that the isotropic equivalent energies of XRFs are lower than those for GRBs, such that they are visible from a reduced range of distances when compared with GRBs. Here we present the results of two-epoch H…
Filaments as Possible Signatures of Magnetic Field Structure in Planetary Nebulae
Huggins, P. J.; Manley, S. P.
We draw attention to the extreme filamentary structures seen in high-resolution optical images of certain planetary nebulae. We determine the physical properties of the filaments in the nebulae IC 418, NGC 3132, and NGC 6537, and based on their large length-to-width ratios, longitudinal coherence, and morphology, we suggest that they may be signat…
Cascades of shocks in active galactic nuclei and their radiation
Courvoisier, T. J. -L.; Türler, M.
We discuss accretion flows on massive black holes in which different elements of the flow (clumps) have velocities that may differ substantially. We estimate the consequence of collisions between these clumps as they come close to the central object and calculate the resulting radiation. We show that this radiation is similar to that observed in t…
The STAFF-DWP wave instrument on the DSP equatorial spacecraft: description and first results
Belmont, G.; Bouzid, V.; Santolík, O. +13 more
The STAFF-DWP wave instrument on board the equatorial spacecraft (TC1) of the Double Star Project consists of a combination of 2 instruments which are a heritage of the Cluster mission: the Spatio-Temporal Analysis of Field Fluctuations (STAFF) experiment and the Digital Wave-Processing experiment (DWP). On DSP-TC1 STAFF consists of a three-axis s…
Cluster at the Bow Shock: Introduction
Balogh, A.; Thomsen, M. F.; Lembège, B. +11 more
Constraints on the distribution of absorption in the X-ray-selected AGN population found in the 13HXMM-Newton/Chandra deep field
McHardy, I.; Page, M. J.; Sasseen, T. +4 more
We present an analysis of the X-ray properties of sources detected in the 13HXMM-Newton deep (200-ks) field. In order to constrain the absorbed active galactic nuclei (AGN) population, we use extensive Monte Carlo simulations to compare directly the X-ray colours of observed sources with those predicted by several model distributions. I…