Search Publications
TYC 8380-1953-1: Discovery of an RS CVn Binary Through the XMM-Newton Slew Survey
Stelzer, B.; López-Santiago, J.; Saxton, R.
In this article we report the discovery of the chromospherically active (RS CVn type) binary TYC 8380-1953-1 through the XMM-Newton slew survey and present results of our optical and X-ray follow-up. With a flux limit of 6 × 10-13 ergs cm-2 s-1 in the soft band (0.2-2 keV), the XMM-Newton slew has a similar sensiti…
Luminosity function of high-mass X-ray binaries and anisotropy in the distribution of active galactic nuclei toward the Large Magellanic Cloud
Tsygankov, S. S.; Lutovinov, A. A.; Grebenev, S. A.
In 2003-2012, the INTEGRAL observatory has performed long-term observations of the Large Magellanic Cloud (LMC). At present, this is one of the deepest hard X-ray (20-60 keV) surveys of extragalactic fields in which more than 20 sources of different natures have been detected. We present the results of a statistical analysis of the population of h…
Investigating the Optical Counterpart Candidates of Four INTEGRAL Sources Localized with Chandra
Rahoui, Farid; Kalemci, Emrah; Bodaghee, Arash +5 more
We report on the optical spectroscopic follow-up observations of the candidate counterparts to four INTEGRAL sources: IGR J04069+5042, IGR J06552-1146, IGR J21188+4901, and IGR J22014+6034. The candidate counterparts were determined with Chandra, and the optical observations were performed with 1.5 m RTT-150 telescope (TÜBİTAK National Observatory…
Substorm-like magnetospheric response to a discontinuity in the Bx component of interplanetary magnetic field
Carlson, C. W.; Angelopoulos, V.; Auster, H. -U. +4 more
We examined the magnetospheric magnetic field and plasma responses to an encounter of a discontinuity in the Bx component of interplanetary magnetic field (IMF). The striking variations of simultaneous solar wind dynamic pressure and IMF-Bz were not observed. Furthermore, we found that this IMF-Bx discontinuity was…
Coronal Mass Ejection Reconstruction from Three Viewpoints via Simulation Morphing. I. Theory and Examples
Frazin, Richard A.
The problem of reconstructing the three-dimensional (3D) density distribution of a coronal mass ejection (CME) from three simultaneous coronagraph observations is timely in that the COR1 and COR2 coronagraphs on the dual-spacecraft STEREO mission complement the LASCO coronagraphs on the SOHO satellite and the Mk4 on Mauna Loa. While the separation…
A Detailed Far-ultraviolet Spectral Atlas of O-type Stars
Smith, Myron A.
In this paper, we present a spectral atlas covering the wavelength interval 930-1188 Å for O2-O9.5 stars using Far-Ultraviolet Spectroscopic Explorer archival data. The stars selected for the atlas were drawn from three populations: Galactic main-sequence (classes III-V) stars, supergiants, and main-sequence stars in the Magellanic Clouds, which h…
A despeckle filter for the Cassini synthetic aperture radar images of Titan's surface
Coustenis, Athena; Solomonidou, Anezina; Bampasidis, Georgios +1 more
Cassini synthetic aperture radar (SAR) images of Titan, the largest satellite of Saturn, reveal surface features with shapes ranging from quasi-circular to more complex ones, interpreted as liquid hydrocarbon deposits assembled in the form of lakes or seas. One of the major problems hampering the derivation of meaningful texture information from S…
The spin of late-type galaxies at redshifts z ≤ 1.2
Hwang, Ho Seong; Park, Changbom; Le Borgne, Damien +2 more
We study the evolution of the galactic spin using data of high-redshift galaxies in the fields of the Great Observatories Origins Deep Survey. Through simple dynamical considerations we estimate the spin for the disc galaxies in our sample and find that its distribution is consistent with that found for nearby galaxies. Defining a dimensionless an…
Chandra Observations of the Nuclear Star Cluster and Ultraluminous X-Ray Sources in NGC 2139
Böker, Torsten; Ho, Luis C.; Shields, Joseph C. +3 more
We report Chandra observations of the Scd galaxy NGC 2139, which is known to host a recently formed (107.6 yr) nuclear star cluster. The star cluster is undetected in X-rays, with an upper bound on 0.5-7 keV luminosity of L X < 7.1 × 1037 erg s-1. This bound implies a bolometric accretion luminosity &…
Matching microlensing events with X-ray sources
Treves, A.; Sartore, N.
Aims: The detection of old neutron stars and stellar mass black holes in isolation is one of the most sought after goals of compact object astrophysics. Microlensing surveys may help in achieving this aim because the lensing mechanism is independent of the emission properties of the lens. Several black hole candidates have indeed been detecte…