XIPE, the X-ray Imaging Polarimetry Explorer, is a mission dedicated to X-ray Astronomy. At the time of
writing XIPE is in a competitive phase A as fourth medium size mission of ESA (M4). It promises to reopen the
polarimetry window in high energy Astrophysics after more than 4 decades thanks to a detector that efficiently
exploits the photoelectric effect and to X-ray optics with large effective area. XIPE uniqueness is time-spectrally-spatially-
resolved X-ray polarimetry as a breakthrough in high energy astrophysics and fundamental physics.
Indeed the payload consists of three Gas Pixel Detectors at the focus of three X-ray optics with a total effective
area larger than one XMM mirror but with a low weight. The payload is compatible with the fairing of the Vega
launcher. XIPE is designed as an observatory for X-ray astronomers with 75 % of the time dedicated to a Guest
Observer competitive program and it is organized as a consortium across Europe with main contributions from
Italy, Germany, Spain, United Kingdom, Poland, Sweden.
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.
The Large Observatory For x-ray Timing (LOFT) was studied within ESA M3 Cosmic Vision framework and participated in the final downselection for a launch slot in 2022-2024. Thanks to the unprecedented combination of effective area and spectral resolution of its main instrument, LOFT will study the behaviour of matter under extreme conditions, such as the strong gravitational field in the innermost regions of accretion flows close to black holes and neutron stars, and the supranuclear densities in the interior of neutron stars. The science payload is based on a Large Area Detector (LAD, 10 m2 effective area, 2-30 keV, 240 eV spectral resolution, 1° 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 status of the mission at the end of its Phase A study.
This paper summarizes the development of a successful project, LAUE, supported by the Italian Space Agency
(ASI) and devoted to the development of long foca length (up to 100—m) Laue lenses for hard X–/soft gamma–
ray astronomy (80-600 keV). The apparatus is ready and the assembling of a prototype lens petal is ongoing.
The great achievement of this project is the use of bent crystals. From measurements obtained on single crystals
and from simulations, we have estimated the expected Point Spread Function and thus the sensitivity of a lens
made of petals. The expected sensitivity is a few ×10−8 photons cm−2 s−1 keV−1). We discuss a number of open astrophysical questions that can settled with such an instrument aboard a free-flying satellite.
The LOFT mission concept is one of four candidates selected by ESA for the M3 launch opportunity as Medium Size missions of the Cosmic Vision programme. The launch window is currently planned for between 2022 and 2024. LOFT is designed to exploit the diagnostics of rapid X-ray flux and spectral variability that directly probe the motion of matter down to distances very close to black holes and neutron stars, as well as the physical state of ultradense matter. These primary science goals will be addressed by a payload composed of a Large Area Detector (LAD) and a Wide Field Monitor (WFM). The LAD is a collimated (<1 degree field of view) experiment operating in the energy range 2-50 keV, with a 10 m2 peak effective area and an energy resolution of 260 eV at 6 keV. The WFM will operate in the same energy range as the LAD, enabling simultaneous monitoring of a few-steradian wide field of view, with an angular resolution of <5 arcmin. The LAD and WFM experiments will allow us to investigate variability from submillisecond QPO’s to yearlong transient outbursts. In this paper we report the current status of the project.
We describe the design and construction of a new novel optical polarimeter (RINGO2) for the Liverpool Telescope.
The instrument is designed for rapid (< 3 minute) followup observations of Gamma Ray Bursts in order to
measure the early time polarization and time evolution on timescales of ~ 1 - 10000 seconds. By using a fast
rotating Polaroid whose rotation is synchronized to control the readout of an electron multiplying CCD eight
times per revolution, we can rebin our data in the time domain after acquisition with little noise penalty, thereby
allowing us to explore the polarization evolution of these rapidly variable objects for the first time.
We report on new results on the development activity of broad band Laue lenses for hard X-/gamma-ray astronomy
(70/100-600 keV). After the development of a first prototype, whose performance was presented at the
SPIE conference on Astronomical Telescopes held last year in Marseille (Frontera et al. 2008), we have improved
the lens assembling technology. We present the the development status of the new lens prototype that is on the
way to be assembled.
We are exploiting the Swift X-ray Telescope (XRT) deepest GRB follow-up observations to study the cosmic
X-Ray Background (XRB) population in the 0.2-10 keV energy band. We present some preliminary results of a
serendipitous survey performed on 221 fields observed with exposure longer than 10 ks. We show that the XRT is
a profitable instrument for surveys and that it is particularly suitable for the search and observation of extended
objects like clusters of galaxies. We used the brightest serendipitous sources and the longest observations to test
the XRT optics performance and the background characteristics all over the field of view, in different energy
bands during the first 2.5 years of fully operational mission.
We describe the design and construction of a novel optical ring-polarimeter (RINGO) for the Liverpool Telescope. The instrument is designed for rapid (< 5 minutes) followup observations of Gamma Ray Bursts in order to measure the early time polarization and its evolution for the first time. Sensitivity calculations and data reduction procedures are described, and the results of on-sky commissioning presented. The instrument is now on the telescope and in routine use during GRB followup.
The Italian-Dutch satellite for x-ray astronomy BeppoSAX is successfully operating on a 600 km equatorial orbit since May 1996. We present here the in-flight performances of the gamma ray burst monitor experiment during its first year of operation. The GRBM is the secondary function of the four CsI(Na) slabs primarily operating as an active anticoincidence of the PDS hard x-ray experiment. It has a geometric area of about 400 cm2 but, due to its location in the core of the satellite its effective area is dependent on the energy and direction of the impinging photons. A dedicated electronics allows to trigger on cosmic gamma-ray bursts. When the trigger condition is satisfied the light curve of the event is recorded from 8 s before to 98 s after the trigger time, with a maximum time resolution of 0.48 ms, in an energy band of 40 - 700 keV. As an instrument housekeeping the 1 s event ratemeter of the same detectors in the same energy band is stored regardless the trigger condition, allowing for an off- line detection of non-triggered events. Finally, the onboard software collects the event count rate that is used as anticoincidence, i.e. the events above a given energy threshold, typically kept at 100 keV. The flight-data screening is in progress, in order to extract real gamma ray bursts from the many sources of background. Already many results have been obtained, as those GRBs detected simultaneously with the wide field cameras oinboard BeppoSAX itself.