Search Publications

Cluster observations of outflowing electron distributions and broadband electrostatic emissions above the polar cap

Belmont, G.; Canu, P.; Fontaine, D. +1 more

We investigate the excellent correlation between ionospheric upgoing electron beams and broadband electrostatic emissions (0-6 kHz) observed by Cluster, at ∼5 to 9 Earth's radii above the polar cap. In the absence of detailed, high time resolution waveform data in that region, we precisely analyzed several electron beams to obtain information conc…

The circumstellar environment of the YSO TMR-1 and a revisit to the candidate very low-mass object TMR-1C

Smith, M. D.; Sterzik, M. F.; Cuby, J. -G. +1 more

Context. TMR-1 (IRAS 04361+2547) is a class I proto-stellar source located in the nearby Taurus star-forming region. Its circumstellar environment is characterized by extended dust emission with complex structures and conspicuous filaments. A faint companion, called TMR-1C, located near the proto-star was detected in previous studies, but its natu…

Detection in the Interstellar Medium of the Weak [Mg II] Transition at 1398.8 Å

Snow, Theodore P.; Destree, Joshua D.; Williamson, Karen E.

High- and medium-resolution ultraviolet spectra from the Space Telescope Imaging Spectrograph and the Goddard High Resolution Spectrograph were used to search for the weak electric quadrupole transitions of [Mg II] near 1398.8 Å. This forbidden doublet was detected in eight sight lines. We calculate an empirical f-value of (1.29 ± 0.13) × 10^-…

Spokes in Saturn's B Ring: Could Lightning be the Cause?

Morfill, Gregor E.; Cravens, Thomas E.; Horanyi, Mihály

Quantitative solar spectroscopy

Wilhelm, K.

Quantitative solar spectroscopy must be based on calibrated instrumentation. The basic requirement of a calibration, i.e., a comparison between the instrument under test and a primary laboratory standard through appropriate procedures, will be briefly reviewed, and the application to modern space instruments will be illustrated. Quantitative measu…

A New Candidate of a Cluster of Galaxies, 2XMM J045637.2+522411

Ueno, Masaru; Koyama, Katsuji; Bamba, Aya +1 more

We present XMM-Newton and Suzaku results of an X-ray source, 2XMM J045637.2+522411, found during an observation of a galactic supernova remnant (SNR), G156.2+5.7. By comparing its radial profile with the point-spread function, we found that 2XMM J045637.2+522411 is an extended source. X-ray spectra exhibited a line-like structure at 5.7-5.8 keV. S…

The unified scheme seen with INTEGRAL detected AGN

Mas-Hesse, J. M.; Gehrels, N.; Ricci, C. +7 more

The INTEGRAL mission provides a large data set for studying the hard X-ray properties of AGN and allows to test the unified scheme for AGN. We present results based on the analysis of 199 AGN. A difference between the Seyfert types is detected in slightly flatter spectra with higher cut-off energies and lower luminosities for the type 2 AGN. When …

Ring current formation influenced by solar wind substorm conditions

Cash, M. D.; Winglee, R. M.; Harnett, E. M.

Single-particle tracking with time-dependent global magnetic and electric fields is used to investigate the generation of the ring current from ionospheric outflows during an internally driven substorm. We show that the energization of the ions is not correlated with the time that the ions leave the ionosphere; instead energization is correlated w…

Mapping Products of Titan's Surface

Barnes, Jason W.; Le Mouélic, Stéphane; Karkoschka, Erich +9 more

Remote sensing instruments aboard the Cassini spacecraft have been observed the surface of Titan globally in the infrared and radar wavelength ranges as well as locally by the Huygens instruments revealing a wealth of new morphological features indicating a geologically active surface. We present a summary of mapping products of Titan's surface de…

Is NP Aqr a new near-contact binary?

Çakırlı, Ö.; İbanoǧlu, C.; Dervişoǧlu, A.

We present radial velocities of the double-lined spectroscopic binary NP Aqr. The radial velocities and the optical light curves obtained by Hipparcos and ASAS-3 are analyzed separately. The masses of the primary and secondary components have been found to be 1.65±0.09 and 0.99±0.05M_⊙, respectively. The cross-correlation functions indic…