|
|
| ATHENA technical and programmatic review report |
Reference: SRE-PA/2011/117
L1 Mission Reformulation, ATHENA
This report summarises the findings of the ESA review on the reformulation of IXO, the International X-ray Observatory (L class mission candidate of the Cosmic Vision 2015-2025 programme), into the new mission concept named ATHENA (Advanced Telescope for High Energy Astrophysics).
The review, completed at the end of the reformulation exercise, establishes the overall feasibility and credibility of the L1 mission candidate reformulated concept - for both platform and payload - for a launch in 2022, and an ESA cost at completion of 850 MEuro (e.c. 2010).
|
| Publication date: 28 Feb 2012 |
|
|
| NGO technical and programmatic review report |
Reference: LISA-EST-RP-1018
L1 Mission Reformulation, NGO
This report summarises the findings of the ESA review on the reformulation of LISA, the Laser Interferometer Space Antenna (L class mission candidate of the Cosmic Vision 2015-2025 programme), into the new mission concept named NGO (New Gravitational wave Observer).
The review, completed at the end of the reformulation exercise, establishes the overall feasibility and credibility of the L1 mission candidate reformulated concept - for both platform and payload - for a launch in 2022, and an ESA cost at completion of 850 MEuro (e.c. 2010).
|
| Publication date: 28 Feb 2012 |
|
|
| Evidence for ultra-fast outflows in radio-quiet AGNs. III. Location and energetics |
| In Press
Using the results of a previous X-ray photo-ionization modelling of blue-shifted Fe K absorption lines on a sample of 42 local radio-quiet AGNs observed with XMM-Newton, in this letter we estimate the location and energetics of the associated ultra-fast outflows (UFOs). Due to significant uncertainties, we are essentially able to place only lower/upper limits. On average, their location is in the interval ~0.0003-0.03pc (~102-104 rs) from the central black hole, consistent with what is expected for accretion disk winds/outflows. The mass outflow rates are constrained between ~0.01-1 M_Sun/yr, corresponding to >5-10% of the accretion rates. The average lower-upper limits on the mechanical power are log(EK_dot)~42.6-44.6 erg/s. However, the minimum possible value of the ratio between the mechanical power and bolometric luminosity is constrained to be comparable or higher than the minimum required by simulations of feedback induced by winds/outflows. Therefore, this work demonstrates that UFOs are indeed capable to provide a significant contribution to the AGN cosmological feedback, in agreement with theoretical expectations and the recent observation of interactions between AGN outflows and the interstellar medium in several Seyferts galaxies. |
| Publication date: 27 Feb 2012 |
|
|
| First submillimetre detection of the TWA brown dwarf disc 2MASSW J1207334-393254 |
| We present Herschel/SPIRE observations for the 2MASS 1207334-393254 (2M1207) system. Based on radiative transfer modelling of near-infrared to submillimetre data, we estimate a disc mass of 3 ± 2 MJup and an outer disc radius of 50-100 AU for the 2M1207A disc. The relative disc mass for 2M1207A is similar to the T Tauri star TW Hya, which indicates that massive discs are not underabundant around substellar objects. In probing the various formation mechanisms for this system, we find that core accretion is highly uncertain mainly due to the large separation between the primary and the companion. Disc fragmentation could be a likely scenario based on analytical models, and if the disc initially was more massive than its current estimate. Considering that the TW Hydrae Association (TWA) is sparsely populated, this system could have formed via one of the known binary formation mechanisms (e.g. turbulent fragmentation of a core) and survived disruption at an early stage. |
| Publication date: 21 Feb 2012 |
|
|
| ATHENA poster |
This double-sided poster summarises ATHENA, a mission devised to reveal the structure of the extreme Universe, from black holes to large-scale structure.
|
| Publication date: 09 Feb 2012 |
|
|
| Rotation period of Venus estimated from Venus Express VIRTIS images and Magellan altimetry |
| The 1.02 micron wavelength thermal emission of the nightside of Venus is strongly anti-correlated to the elevation of the surface. The VIRTIS instrument on Venus Express has mapped this emission and therefore gives evidence for the orientation of Venus between 2006 and 2008. The Magellan mission provided a global altimetry data set recorded between 1990 and 1992. Comparison of these two data sets reveals a deviation in longitude indicating that the rotation of the planet is not fully described by the orientation model recommended by the IAU. This deviation is sufficiently large to affect estimates of surface emissivity from infrared imaging. A revised period of rotation of Venus of 243.023 ± 0.002 d aligns the two data sets. This period of rotation agrees with pre-Magellan estimates but is significantly different from the commonly accepted value of 243.0185 ± 0.0001 d estimated from Magellan radar images. It is possible that this discrepancy stems from a length of day variation with the value of 243.023 ± 0.002 d representing the average of the rotation period over 16 years. |
| Publication date: 01 Feb 2012 |
|
|
