Search Publications
The Ly α and Ly β Profiles in Solar Prominences and Prominence Fine Structure
Vial, J. -C.; Ajabshirizadeh, A.; Ebadi, H.
Ly α and Ly β line profiles in a solar prominence were observed with high spatial and spectral resolution with SOHO/SUMER. Within a 60-arcsec scan, we measure a very large variety of profiles: not only reversed and nonreversed profiles but also red-peaked and blue-peaked ones in both lines. Such a spatial variability is probably related to both th…
A new superwind galaxy: XMM-Newton observations of NGC 6810
Strickland, David K.
We present the first imaging X-ray observation of the highly inclined (i = 78°) Sab Seyfert 2 galaxy NGC 6810 using XMM-Newton, which reveals soft X-ray emission that extends out to a projected height of ~7 kpc away from the plane of the galaxy. The soft X-ray emission beyond the optical disc of the galaxy is most plausibly extraplanar, although i…
E-type asteroid (2867) Steins: flyby target for Rosetta
Barucci, M. A.; Fulchignoni, M.; Vernazza, P. +3 more
Aims:The mineralogy of the asteroid (2867) Steins was investigated in the framework of a ground-based science campaign dedicated to the future encounter with Rosetta spacecraft.
Methods: Near-infrared (NIR) spectra of the asteroid in the 0.8-2.5 µm spectral range have been obtained with SpeX/IRTF in remote-observing mode from Meudon, Fra…
On the dynamic nature of the prolate solar chromosphere: jet formation
Filippov, B.; Koutchmy, S.; Vilinga, J.
Context: In "cool" spectral lines, the smoothed upper edge of the solar chromosphere is prolate in the South-North direction at the epoch of minimum solar activity and nearly spherically symmetric at the maximum phase. We attribute the effect to the dynamical nature of the upper chromosphere, which consists of a large number of small jet-like stru…
An X-Ray Spectral Analysis of the Central Regions of NGC 4593
Kaiser, Mary Elizabeth; Brenneman, Laura W.; Wilms, Jörn +1 more
We present a detailed analysis of XMM-Newton EPIC-pn data for the Seyfert 1 galaxy NGC 4593. We discuss the X-ray spectral properties of this source, as well as its variations with time. The 0.5-10 keV spectrum shows significant complexity beyond a simple power-law form, with clear evidence existing for a ``soft excess,'' as well as absorption by …
XMM observation of 1RXS J180431.1-273932: a new M-type X-ray binary with a 494 s-pulse period neutron star?
Guainazzi, M.; Nucita, A. A.; Carpano, S.
Context: Low-mass X-ray binaries are peculiar binary systems composed of a compact object and a low-mass star. Recently, a new class of these systems, known as symbiotic X-ray binaries (with a neutron star with a M-type giant companion), has been discovered.
Aims: Here, we present long-duration XMM observations of the source 1RXS J180431.1-273…
A longer XMM-Newton look at I Zwicky - 1. Distinct modes of X-ray spectral variability
Brandt, W. N.; Costantini, E.; Fabian, A. C. +1 more
The short-term spectral variability of the narrow-line Seyfert 1 galaxy I Zwicky 1 (I Zw 1) as observed in an 85ks XMM-Newton observation is discussed in detail. I Zw 1 shows distinct modes of variability prior to and after a flux dip in the broad-band light curve. Before the dip the variability can be described as arising from changes in shape an…
The Star-forming Region NGC 346 in the Small Magellanic Cloud with Hubble Space Telescope ACS Observations. II. Photometric Study of the Intermediate-Age Star Cluster BS 90
Henning, Thomas; Gouliermis, Dimitrios A.; Dolphin, Andrew E. +2 more
We present the results of our investigation of the intermediate-age star cluster BS 90, located in the vicinity of the H II region N66 in the SMC, observed with HST ACS. The high-resolution data provide a unique opportunity for a very detailed photometric study performed on one of the rare intermediate-age rich SMC clusters. The complete set of ob…
Adaptive Optics Imaging of IRAS 18276-1431: A Bipolar Preplanetary Nebula with Circumstellar ``Searchlight Beams'' and ``Arcs''
Sahai, R.; Sánchez Contreras, C.; Le Mignant, D. +2 more
We present high angular resolution images of the post-AGB nebula IRAS 18276-1431 (also known as OH 17.7-2.0) obtained with the Keck II adaptive optics (AO) system in its natural guide star (NGS) mode in the Kp, Lp, and Ms near-infrared bands. We also present supporting optical F606W and F814W HST images as well as …
Chandra and XMM-Newton Discovery of Transient X-Ray Pulsar in the Nearby Spiral Galaxy NGC 2403
Córdova, France A.; Trudolyubov, Sergey P.; Priedhorsky, William C.
We report on the discovery and analysis of the transient X-ray pulsar CXOU J073709.1+653544 detected in the 2004 August-October Chandra and XMM-Newton observations of the nearby spiral galaxy NGC 2403. The X-ray source exhibits X-ray pulsations with a period P~18 s and a nearly sinusoidal pulse shape and pulsed fraction 46%-70% during the first th…