Search Publications
The 2007 outburst of the X-ray binary XTE J1856+053
Greiner, J.; Sala, G.; Ajello, M. +1 more
Aims: On 28 February 2007 a new outburst of the previously known transient source XTE J1856+053 was detected with RXTE/ASM. We present here the results of an XMM-Newton (0.5-10.0 keV) Target of Opportunity observation performed on 14 March 2007, aimed at constraining the mass of the compact object in this X-ray binary and determining its main prop…
X-ray study of accretion flow in narrow-line Seyfert 1 galaxies
Terashima, Y.; Haba, Y.; Kunieda, H. +1 more
We present the results of a systematic study of narrow-line Seyfert 1 galaxies (NLS1s) observed with XMM-Newton. The 2 12 keV X-ray spectra of NLS1s are well represented by a single power law with a photon index Γ ∼ 2. When this hard power law continuum is extrapolated into the low energy band, we found that all objects in our sample show prominen…
XMM-Newton observations across the Cygnus Loop from northeastern rim to southwestern rim
Katsuda, Satoru; Tsunemi, Hiroshi
We have observed the Cygnus Loop from the northeast (NE) to the southwest (SW) with XMM-Newton. We extracted spectra from 3‧-spaced annular regions across the Loop and fitted them either with a one-kTe-component non-equilibrium ionization (NEI) model or with two-kTe-component NEI model. We found that the two-kTe-co…
A Glimpse into the Past: The Recent Evolution of Globular Clusters
Anderson, Jay; Strader, Jay; Richer, Harvey B. +1 more
We present the serendipitous discovery of 195 extragalactic globular clusters (GCs) in one of the deepest optical images ever obtained, a 126 orbit Hubble Space Telescope (HST) Advanced Camera for Surveys (ACS) imaging study of the nearby Galactic GC NGC 6397. The distant GCs are all found surrounding a bright elliptical galaxy in the field and ar…
Late-Time HST Photometry of SN 1994I: Hints of Positron Annihilation Energy Deposition
Filippenko, Alexei V.; Garnavich, Peter; Fransson, Claes +12 more
We present multicolor Hubble Space Telescope (HST) WFPC2 broadband observations of the Type Ic SN 1994I obtained ∼280 d after maximum light. We measure the brightness of the SN and, relying on the detailed spectroscopic database of SN 1994I, we transform the ground-based photometry obtained at early times to the HST photometric system, deriving li…
Heliospheric sector boundaries: Single or multiple?
Neugebauer, Marcia
Solar wind data were examined for a period when the Ulysses spacecraft moved roughly parallel to the boundary between inward and outward interplanetary fields at a solar distance of 1.4 AU. Multiple crossings of the magnetic sector boundary were observed. Three tests were used to evaluate whether or not the crossings were due to multiple crossings…
Saturnian icy satellites: Disk-integrated observations of the brightness opposition surge at low phase angles
Kulyk, Irina
Photopolarimetric observations of Saturn's satellites Enceladus, Tethys, Dione, and Rhea were obtained with the 2 m RCC telescope at the National Astronomical Observatory, Rozhen, in two different phase-angle regions (from 0.07° to 0.01° and from 5.6° to 5.2°). In this paper we present the first results of disk-integrated satellite photometry incl…
A study of the X-ray pulsars X1845-024 and XTE J1858+034 based on INTEGRAL observations
Doroshenko, V. A.; Doroshenko, R. F.; Postnov, K. A. +2 more
We present an analysis of observations of the relatively unstudied X-ray pulsars X1845-024 and XTE J1858+034 carried out from May 2003 through November 2004 using the JEM-X and IBIS telescopes of the INTEGRAL international gamma-ray observatory at energies of 5-70 keV. The X-ray spectra and light curves of the pulsars are constructed. During the o…
Rosetta in the year of the swing-bys
Montagnon, Elsa; Ferri, Paolo; Accomazzo, Andrea +1 more
The International Rosetta Mission, a cornerstone mission of the European Space Agency Scientific Programme, was launched on 2nd March 2004 on its 10 years journey towards a rendezvous with comet Churyumov-Gerasimenko. Once reached the comet nucleus in summer 2014, Rosetta will orbit it for about 1.5 years down to distances of a few kilometres and …
Meteoroid and space debris impacts in grazing-incidence telescopes
Carpenter, J. D.; Wells, A.; Abbey, A. F. +1 more
Context: Micrometeoroid or space debris impacts have been observed in the focal planes of the XMM-Newton and Swift-XRT (X-ray Telescope) X-ray observatories. These impacts have resulted in damage to, and in one case the failure of, focal-plane Charge-Coupled Device (CCDs) detectors.
Aims: We aim to quantify the future risks of focal-plane impa…