Search Publications
Spectral energy distributions of H ii regions in M 33 (HerM33es)
Boquien, M.; Braine, J.; Calzetti, D. +16 more
Aims: Within the framework of the Herschel M 33 extended survey HerM33es and in combination with multi-wavelength data we study the spectral energy distribution (SED) of a set of H ii regions in the Local Group galaxy M 33 as a function of the morphology. We analyse the emission distribution in regions with different morphologies and present …
Meter-sized Moonlet Population in Saturn's C Ring and Cassini Division
Colwell, Joshua E.; Esposito, Larry W.; Lewis, Mark C. +1 more
Stellar occultations observed by the Cassini Ultraviolet Imaging Spectrograph reveal the presence of transparent holes a few meters to a few tens of meters in radial extent in otherwise optically thick regions of the C ring and the Cassini Division. We attribute the holes to gravitational disturbances generated by a population of ~10 m boulders in…
Blue Straggler Evolution Caught in the Act in the Large Magellanic Cloud Globular Cluster Hodge 11
Deng, Licai; de Grijs, Richard; Li, Chengyuan +1 more
High-resolution Hubble Space Telescope imaging observations show that the radial distribution of the field-decontaminated sample of 162 "blue straggler" stars (BSs) in the 11.7^{+0.2}_{-0.1} Gyr old Large Magellanic Cloud cluster Hodge 11 exhibits a clear bimodality. In combination with their distinct loci in color-magnitude space, this offers new…
The X-ray/UV absorber in NGC 4593
Kaastra, J. S.; Kriss, G. A.; Costantini, E. +2 more
We present the results of a recent (2011 March) 160 ks Chandra-LETGS (Low Energy Transmission Grating Spectrometre) observation of the Seyfert galaxy NGC 4593, and the analysis of archival X-ray and UV spectra taken with XMM-Newton and Hubble Space Telescope (HST)/STIS (Space Telescope Imaging Spectrograph) in 2002. We find evidence of a multi-com…
Dispersion of low frequency plasma waves upstream of the quasi-perpendicular terrestrial bow shock
Walker, S. N.; Balikhin, M. A.; Pope, S. A. +1 more
Low frequency waves in the foot of a supercritical quasi-perpendicular shock front have been observed since the very early in situ observations of the terrestrial bow shock (Guha et al., 1972). The great attention that has been devoted to these type of waves since the first observations is explained by the key role attributed to them in the proces…
Solar cycle modulation of Titan's ionosphere
Wahlund, J. -E.; Edberg, N. J. T.; Ågren, K. +5 more
During the six Cassini Titan flybys T83-T88 (May 2012 to November 2012) the electron density in the ionospheric peak region, as measured by the radio and plasma wave science instrument/Langmuir probe, has increased significantly, by 15-30%, compared to previous average. These measurements suggest that a long−term change has occurred in the ionosph…
The Paα Luminosity Function of H II Regions in Nearby Galaxies from HST/NICMOS
Calzetti, Daniela; Schinnerer, Eva; Egusa, Fumi +5 more
The H II region luminosity function (LF) is an important tool for deriving the birthrates and mass distribution of OB associations and is an excellent tracer of the newly formed massive stars and associations. To date, extensive work (predominantly in Hα) has been done from the ground, which is hindered by dust extinction and the severe blending o…
Swift J053041.9-665426, a new Be/X-ray binary pulsar in the Large Magellanic Cloud
Pietsch, W.; Haberl, F.; Sturm, R. +4 more
Aims: We observed the newly discovered X-ray source Swift J053041.9-665426in the X-ray and optical regime to confirm its proposed nature as a high mass X-ray binary.
Methods: We obtained XMM-Newton and Swift X-ray data, along with optical observations with the ESO Faint Object Spectrograph, to investigate the spectral and temporal charac…
Separator reconnection with antiparallel/component features observed in magnetotail plasmas
Zong, Qiugang; He, Jiansen; Xie, Lun +8 more
reconnection (MR), a fundamental process in space plasmas that changes magnetic topology and converts magnetic energy into kinetic and thermal energies, is an ultimate driver of space weather. There exist two models of MR in the literatures, antiparallel and component, associated with intensive studies of their generation and applications. In this…
Deep Chandra Monitoring Observations of NGC 4649. I. Catalog of Source Properties
Zezas, A.; Luo, B.; Gallagher, J. S. +6 more
We present the X-ray source catalog for the Chandra monitoring observations of the elliptical galaxy, NGC 4649. The galaxy has been observed with Chandra ACIS-S3 in six separate pointings, reaching a total exposure of 299 ks. There are 501 X-ray sources detected in the 0.3-8.0 keV band in the merged observation or in one of the six individual obse…