Search Publications
On the Absence of Non-thermal X-Ray Emission around Runaway O Stars
Toalá, J. A.; Oskinova, L. M.; Ignace, R.
Theoretical models predict that the compressed interstellar medium around runaway O stars can produce high-energy non-thermal diffuse emission, in particular, non-thermal X-ray and γ-ray emission. So far, detection of non-thermal X-ray emission was claimed for only one runaway star, AE Aur. We present a search for non-thermal diffuse X-ray emissio…
Dense Gas in the Outer Spiral Arm of M51
Gao, Yu; Koda, Jin; Gu, Qiusheng +2 more
There is a linear relation between the mass of dense gas traced by the HCN(1-0) luminosity and the star formation rate (SFR) traced by the far-infrared luminosity. Recent observations of galactic disks have shown some systematic variations. In order to explore the SFR-dense gas link at high resolution (∼4″, ∼150 pc) in the outer disk of an externa…
3D Polarized Imaging of Coronal Mass Ejections: Chirality of a CME
de Koning, C. A.; Elliott, H. A.; DeForest, C. E.
We report on a direct polarimetric determination of the chirality of a coronal mass ejection (CME), using the physics of Thomson scattering applied to synoptic polarized images from the Solar Terrestrial Relations Observatories/COR2 coronagraph. We confirmed the determination using in situ magnetic field measurements of the same CME with the ACE s…
X-ray study of bow shocks in runaway stars
De Becker, M.; Romero, G. E.; del Valle, M. V. +2 more
Massive runaway stars produce bow shocks through the interaction of their winds with the interstellar medium, with the prospect for particle acceleration by the shocks. These objects are consequently candidates for non-thermal emission. Our aim is to investigate the X-ray emission from these sources. We observed with XMM-Newton a sample of five bo…
A Far-ultraviolet Fluorescent Molecular Hydrogen Emission Map of the Milky Way Galaxy
Edelstein, Jerry; Jo, Young-Soo; Min, Kyoung-Wook +2 more
We present the far-ultraviolet (FUV) fluorescent molecular hydrogen (H2) emission map of the Milky Way Galaxy obtained with FIMS/SPEAR covering ∼76% of the sky. The extinction-corrected intensity of the fluorescent H2 emission has a strong linear correlation with the well-known tracers of the cold interstellar medium (ISM), i…
Synchrotron emission from the blazar PG 1553+113. An analysis of its flux and polarization variability
Lähteenmäki, A.; Giroletti, M.; Villata, M. +59 more
In 2015 July 29-September 1, the satellite XMM-Newton pointed at the BL Lac object PG 1553+133 six times, collecting data for 218 h. During one of these epochs, simultaneous observations by the Swift satellite were requested to compare the results of the X-ray and optical-UV instruments. Optical, near-infrared and radio monitoring was carried out …
An Ultraviolet Survey of Low-redshift Partial Lyman-limit Systems with the HST Cosmic Origins Spectrograph
Stevans, Matthew L.; Shull, J. Michael; Danforth, Charles W. +2 more
We present an ultraviolet spectroscopic survey of strong H I absorbers in the intergalactic medium, probing their evolution over the last 6-7 Gyr at redshifts 0.24 ≤ z ≤ 0.84. We measure column densities N H I (cm-2) from the pattern of Lyman-series absorption lines and flux decrement at the Lyman limit (LL) when available. …
Investigating short-time-scale variations in cometary ions around comet 67P
Karlsson, Tomas; Simon Wedlund, Cyril; Nilsson, Hans +10 more
The highly varying plasma environment around comet 67P/Churyumov-Gerasimenko inspired an upgrade of the ion mass spectrometer (Rosetta Plasma Consortium Ion Composition Analyzer) with new operation modes, to enable high time resolution measurements of cometary ions. Two modes were implemented, one having a 4 s time resolution in the energy range 0…
Migration and kinematics in growing disc galaxies with thin and thick discs
Binney, James; Schönrich, Ralph; Aumer, Michael
We analyse disc heating and radial migration in N-body models of growing disc galaxies with thick and thin discs. Similar to thin-disc-only models, galaxies with appropriate non-axisymmetric structures reproduce observational constraints on radial disc heating in and migration to the Solar Neighbourhood (Snhd). The presence of thick discs can supp…
Observational evidence that positive and negative AGN feedback depends on galaxy mass and jet power
Page, M. J.; Hardcastle, M. J.; Elvis, M. +6 more
Several studies support the existence of a link between the active galactic nucleus (AGN) and star formation activity. Radio jets have been argued to be an ideal mechanism for direct interaction between the AGN and the host galaxy. A drawback of previous surveys of AGN is that they are fundamentally limited by the degeneracy between redshift and l…