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Composition and chemistry of Titan's stratosphere

Bézard, Bruno

X-ray Sources and their Optical Counterparts in the Galactic Globular Cluster M12 (NGC 6218)

Anderson, Scott F.; Kong, Albert K. H.; Verbunt, Frank +4 more

We study a Chandra X-ray Observatory ACIS-S observation of the Galactic globular cluster M12. With a 26 ks exposure time, we detect six X-ray sources inside the half-mass radius (2farcm16) of which two are inside the core radius (0farcm72) of the cluster. If we assume that these sources are all associated with globular cluster M12, the luminosity …

Plasma waves above the ion cyclotron frequency in the solar wind: a review on observations

Briand, C.

Since the very beginning of the space venture, discrepancies between hydrodynamic models and observations have raised the attention to the kinetic effects taking place in the interplanetary medium. After discussing some of these constraints, a review on the state of the art knowledge on the waves in the range f_ci<f<f_pe …

Seasonal variations of photochemical tracers at low and middle latitudes on Mars: Observations and models

Krasnopolsky, Vladimir A.

Mars Express observations give ozone abundances that are smaller than those from the ground-based infrared heterodyne and HST observations at low and middle latitudes. Both ground-based and Mars Express observations of the O ₂ dayglow at 1.27 µm, which originates from photolysis of ozone, are in mutual agreement after correction f…

Chandra Observations of Nuclear X-Ray Emission from Low Surface Brightness Galaxies

Reynolds, C. S.; Das, M.; Vogel, S. N. +2 more

We present Chandra detections of X-ray emission from the active galactic nuclei (AGN) in two giant low surface brightness (LSB) galaxies, UGC 2936 and UGC 1455. Their X-ray luminosities are 1.8 × 10⁴² ergs s^-1 and 1.1 × 10⁴⁰ ergs s^-1 respectively. Of the two galaxies, UGC 2936 is radio loud. Together wit…

Reconnection Electric Field and Hardness of X-Ray Emission of Solar Flares

Liu, Chang; Wang, Haimin

Magnetic reconnection is believed to be the prime mechanism that triggers solar flares and accelerates electrons up to energies of MeV. In the classical two-dimensional reconnection model, the separation motion of chromospheric ribbons, manifests the successive reconnection that takes place higher up in the corona. Meanwhile, downward traveling en…

Overdensities of Galaxies at z ~ 3.7 in Chandra Deep Field-South

Im, Myungshin; Kang, Eugene

We report the discovery of possible overdensities of galaxies at z ~ 3.7 in Chandra Deep Field-South (CDF-S). These overdensities are identified from a photometric redshift-selected sample and a BVz-selected sample. One overdensity is identified in the proximity of two active galactic nuclei and Lyman break galaxies at z = 3.66 and z = 3.70 at 7σ …

Three frontside full halo coronal mass ejections with a nontypical geomagnetic response

Zhukov, A. N.; Rodriguez, L.; Schmieder, B. +9 more

Forecasting potential geoeffectiveness of solar disturbances (in particular, of frontside full halo coronal mass ejections) is important for various practical purposes, e.g., for satellite operations, radio communications, global positioning system applications, power grid, and pipeline maintenance. We analyze three frontside full halo coronal mas…

INTEGRAL and XMM-Newton Spectroscopy of GX 339-4 during Hard/Soft Intermediate and High/Soft States in the 2007 Outburst

Mas-Hesse, J. M.; Fabian, A. C.; Miller, J. M. +5 more

We present simultaneous XMM-Newton and International Gamma-Ray Astrophysics Laboratory (INTEGRAL) observations of the luminous black hole transient and relativistic jet source GX 339-4. GX 339-4 started an outburst on 2006 November and our observations were undertaken from 2007 January to March. We triggered five INTEGRAL and three XMM-Newton Targ…

An Infrared Spectroscopic Study of Amorphous and Crystalline Ices of Vinylacetylene and Implications for Saturn's Satellite Titan

Kaiser, R. I.; Kim, Y. S.

Laboratory infrared spectra of amorphous and crystalline vinylacetylene ices were recorded in the range of 7000-400 cm^-1. The spectra showed several amorphous features in the ice deposited at 10 K, which were then utilized to monitor a phase transition between 93 ± 1 K to form the crystalline structure. Successive heating allows monitor…