99 research outputs found
The BRITE-Constellation Nanosatellite Space Mission And Its First Scientific Results
The BRIght Target Explorer (BRITE) Constellation is the first nanosatellite
mission applied to astrophysical research. Five satellites in low-Earth orbits
perform precise optical two-colour photometry of the brightest stars in the
night sky. BRITE is naturally well suited for variability studies of hot stars.
This contribution describes the basic outline of the mission and some initial
problems that needed to be overcome. Some information on BRITE data products,
how to access them, and how to join their scientific exploration is provided.
Finally, a brief summary of the first scientific results obtained by BRITE is
given.Comment: 5 pages, 1 figure, to appear in the proceedings of "Seismology of the
Sun and the Distant Stars 2016. Using Today's Successes to Prepare the
Future. Joint TASC2/KASC9 Workshop - SPACEINN/HELAS8 Conference", ed. M. J.
P. F. G. Monteir
The LOFT mission concept: A status update
The Large Observatory For x-ray Timing (LOFT) is a mission concept which was proposed to ESA as M3 and M4 candidate in the framework of the Cosmic Vision 2015-2025 program. Thanks to the unprecedented combination of effective area and spectral resolution of its main instrument and the uniquely large field of view of its wide field monitor, LOFT will be able to study the behaviour of matter in extreme conditions such as the strong gravitational field in the innermost regions close to black holes and neutron stars and the supra-nuclear densities in the interiors of neutron stars. The science payload is based on a Large Area Detector (LAD, >8m2 effective area, 2-30 keV, 240 eV spectral resolution, 1 degree collimated field of view) and a Wide Field Monitor (WFM, 2-50 keV, 4 steradian field of view, 1 arcmin source location accuracy, 300 eV spectral resolution). The WFM is equipped with an on-board system for bright events (e.g., GRB) localization. The trigger time and position of these events are broadcast to the ground within 30 s from discovery. In this paper we present the current technical and programmatic status of the mission
Catalogue of BRITE-Constellation targets I. Fields 1 to 14 (November 2013 - April 2016)
The BRIght Target Explorer (BRITE) mission collects photometric time series
in two passbands aiming to investigate stellar structure and evolution. Since
their launches in the years 2013 and 2014, the constellation of five BRITE
nano-satellites has observed a total of more than 700 individual bright stars
in 64 fields. Some targets have been observed multiple times. Thus, the total
time base of the data sets acquired for those stars can be as long as nine
years. Our aim is to provide a complete description of ready-to-use BRITE data,
to show the scientific potential of the BRITE-Constellation data by identifying
the most interesting targets, and to demonstrate and encourage how scientists
can use these data in their research. We apply a decorrelation process to the
automatically reduced BRITE-Constellation data to correct for instrumental
effects. We perform a statistical analysis of the light curves obtained for the
300 stars observed in the first 14 fields during the first ~2.5 years of the
mission. We also perform cross-identification with the International Variable
Star Index. We present the data obtained by the BRITE-Constellation mission in
the first 14 fields it observed from November 2013 to April 2016. We also
describe the properties of the data for these fields and the 300 stars observed
in them. Using these data, we detected variability in 64% of the presented
sample of stars. Sixty-four stars or 21.3% of the sample have not yet been
identified as variable in the literature and their data have not been analysed
in detail. They can therefore provide valuable scientific material for further
research. All data are made publicly available through the BRITE Public Data
Archive and the Canadian Astronomy Data Centre.Comment: accepted by Astronomy & Astrophysics, 13 pages main text, 22 pages of
appendi
The Spectrometer/Telescope for Imaging X-rays (STIX)
Aims. The Spectrometer Telescope for Imaging X-rays (STIX) on Solar Orbiter is a hard X-ray imaging spectrometer, which covers the energy range from 4 to 150 keV. STIX observes hard X-ray bremsstrahlung emissions from solar flares and therefore provides diagnostics of the hottest (âȘ10 MK) flare plasma while quantifying the location, spectrum, and energy content of flare-accelerated nonthermal electrons.
Methods. To accomplish this, STIX applies an indirect bigrid Fourier imaging technique using a set of tungsten grids (at pitches from 0.038 to 1 mm) in front of 32 coarsely pixelated CdTe detectors to provide information on angular scales from 7 to 180 arcsec with 1 keV energy resolution (at 6 keV). The imaging concept of STIX has intrinsically low telemetry and it is therefore well-suited to the limited resources available to the Solar Orbiter payload. To further reduce the downlinked data volume, STIX data are binned on board into 32 selectable energy bins and dynamically-adjusted time bins with a typical duration of 1 s during flares.
Results. Through hard X-ray diagnostics, STIX provides critical information for understanding the acceleration of electrons at the Sun and their transport into interplanetary space and for determining the magnetic connection of Solar Orbiter back to the Sun. In this way, STIX serves to link Solar Orbiterâs remote and in-situ measurements
The design of the wide field monitor for LOFT
LOFT (Large Observatory For x-ray Timing) is one of the ESA M3 missions
selected within the Cosmic Vision program in 2011 to carry out an assessment
phase study and compete for a launch opportunity in 2022-2024. The phase-A
studies of all M3 missions were completed at the end of 2013. LOFT is designed
to carry on-board two instruments with sensitivity in the 2-50 keV range: a 10
m 2 class Large Area Detector (LAD) with a <1{\deg} collimated FoV and a wide
field monitor (WFM) making use of coded masks and providing an instantaneous
coverage of more than 1/3 of the sky. The prime goal of the WFM will be to
detect transient sources to be observed by the LAD. However, thanks to its
unique combination of a wide field of view (FoV) and energy resolution (better
than 500 eV), the WFM will be also an excellent monitoring instrument to study
the long term variability of many classes of X-ray sources. The WFM consists of
10 independent and identical coded mask cameras arranged in 5 pairs to provide
the desired sky coverage. We provide here an overview of the instrument design,
configuration, and capabilities of the LOFT WFM. The compact and modular design
of the WFM could easily make the instrument concept adaptable for other
missions.Comment: Proc. SPIE 9144, Space Telescopes and Instrumentation 2014:
Ultraviolet to Gamma Ray, 91442
Observing GRBs with the LOFT Wide Field Monitor
LOFT (Large Observatory For X-ray Timing) is one of the four candidate missions currently under assessment study for the M3 mission in ESAs Cosmic Vision program to be launched in 2024. LOFT will carry two instruments with prime sensitivity in the 2-30 keV range: a 10 m2 class large area detector (LAD) with a <1° collimated field of view and a wide field monitor (WFM) instrument. The WFM is based on the coded mask principle, and 5 camera units will provide coverage of more than 1/3 of the sky. The prime goal of the WFM is to detect transient sources to be observed by the LAD. With its wide field of view and good energy resolution of <500 eV, the WFM will be an excellent instrument for detecting and studying GRBs and X-ray flashes. The WFM will be able to detect ~150 gamma ray bursts per year, and a burst alert system will enable the distribution of ~100 GRB positions per year with a ~1 arcmin location accuracy within 30 s of the burst
Compton Large Area Silicon Timing Tracker for Cosmic Vision M3
International audienceProposed in response to the ESA call for the third Medium size mission (M3), CAPSiTT is a small mission designed for a 3-year survey of the non-thermal high energy sky from an equatorial LEO orbit. With a large effective area and a very wide field of view, its single instrument, a silicon tracker, provides good imaging, spectroscopic and polarimetric capabilities with a sensitivity 10-100 times better than COMPTEL. Nucleosynthesis and particle acceleration mechanisms in various sites are the main scientific topics addressed by CAPSiTT
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