| 1. |
- Prusti, T., et al.
(författare)
-
The Gaia mission
- 2016
-
Ingår i: Astronomy and Astrophysics. - : EDP Sciences. - 0004-6361 .- 1432-0746. ; 595
-
Tidskriftsartikel (refereegranskat)abstract
- Gaia is a cornerstone mission in the science programme of the European Space Agency (ESA). The spacecraft construction was approved in 2006, following a study in which the original interferometric concept was changed to a direct-imaging approach. Both the spacecraft and the payload were built by European industry. The involvement of the scientific community focusses on data processing for which the international Gaia Data Processing and Analysis Consortium (DPAC) was selected in 2007. Gaia was launched on 19 December 2013 and arrived at its operating point, the second Lagrange point of the Sun-Earth-Moon system, a few weeks later. The commissioning of the spacecraft and payload was completed on 19 July 2014. The nominal five-year mission started with four weeks of special, ecliptic-pole scanning and subsequently transferred into full-sky scanning mode. We recall the scientific goals of Gaia and give a description of the as-built spacecraft that is currently (mid-2016) being operated to achieve these goals. We pay special attention to the payload module, the performance of which is closely related to the scientific performance of the mission. We provide a summary of the commissioning activities and findings, followed by a description of the routine operational mode. We summarise scientific performance estimates on the basis of in-orbit operations. Several intermediate Gaia data releases are planned and the data can be retrieved from the Gaia Archive, which is available through the Gaia home page.
|
|
| 2. |
|
|
| 3. |
- Coffineau, L., et al.
(författare)
-
INSIGHT_E-A Think Tank Informing the European Commission
- 2017
-
Ingår i: Europe's Energy Transition - Insights for Policy Making. - : Elsevier. - 9780128098066 - 9780128099032 ; , s. 11-20
-
Bokkapitel (refereegranskat)abstract
- INSIGHT_E is a think tank that offers unbiased energy policy advice and insights to the European Commission. The consortium forming INSIGHT_E combines a multidisciplinary group of 12 different partners based in nine different European countries. In order to provide energy policy advice and insights, it has developed tools and instruments to assess the impact of the energy transition in all its dimensions, including its drivers. Its three main types of publications include Rapid Response Energy Briefs, Hot Energy Topics, and Policy Reports. Its fourth key output is an Observatory, which provides access to all of INSIGHT_E's publications, tools, and instruments, including webinars, information corners, and statistical indicators on the energy transition of the European Union.
|
|
| 4. |
- Laskar, Tanmoy, et al.
(författare)
-
The Radio to GeV Afterglow of GRB 221009A
- 2023
-
Ingår i: Astrophysical Journal Letters. - : American Astronomical Society. - 2041-8205 .- 2041-8213. ; 946:1
-
Tidskriftsartikel (refereegranskat)abstract
- GRB 221009A ($z=0.151$) is one of the closest known long $gamma$-ray bursts (GRBs). Its extreme brightness across all electromagnetic wavelengths provides an unprecedented opportunity to study a member of this still-mysterious class of transients in exquisite detail. We present multi-wavelength observations of this extraordinary event, spanning 15 orders of magnitude in photon energy from radio to $gamma$-rays. We find that the data can be partially explained by a forward shock (FS) from a highly-collimated relativistic jet interacting with a low-density wind-like medium. The jet's beaming-corrected kinetic energy ($E_K sim 4times10<^>{50}$ erg) is typical for the GRB population, but its opening angle ($sim2<^>{circ}$) is one of the narrowest. The radio and mm data provide strong limiting constraints on the FS model, but require the presence of an additional emission component. From equipartition arguments, we find that the radio emission is likely produced by a small amount of mass ($lesssim6times10<^>{-7} M_odot$) moving relativistically ($Gammagtrsim9$) with a large kinetic energy ($gtrsim10<^>{49}$ erg). However, the temporal evolution of this component does not follow prescriptions for synchrotron radiation from a single power-law distribution of electrons (e.g. in a reverse shock or two-component jet), or a thermal electron population, perhaps suggesting that one of the standard assumptions of afterglow theory is violated. GRB 221009A will likely remain detectable with radio telescopes for years to come, providing a valuable opportunity to track the full lifecycle of a powerful relativistic jet.
|
|
