The high energy astrophysics group in the light of SHARJAH-SAT-1 and future projects

The newly formed High Energy Astrophysics (HEA) Group at the Sharjah Academy of Astronomy, Space Science, and Technology (SAASST) and the University of Sharjah (UoS) focuses on the accretion processes onto compact objects, mainly on neutron stars and black holes, across the electromagnetic spectrum. Our research lies on observations of Galactic black holes as well as accreting neutron stars in both high and low mass X-ray binary systems. An extensive research programme on accreting compact objects utilizes an armada of X-ray observsatories (e.g., XMM-Newton/ESA, Chandra/NASA, INTEGRAL/ESA, Neil Gehrels Swift Observatory/NASA, NuStar/NASA, etc) alongside major ground-based facilities such as the European's Southen Observatory (ESO), Very Large Telescope (VLT) and smaller 1m-class telescopes. Besides the observational part, in our research group we are using an advanced inventory of state-of-the-art tools such as (magneto)hydrodynamical and General-Relativistic (magneto)hydrodynamical simulations, alongside radiative transfer and ray-tracing tools to further study and shed light onto the elusive nature of these accreting compact objects and their surrounding environment. Moreover, this group will provide a direct science exploitation of the forthcoming 3U CubeSat SHARJAHSAT-1. The primary science payload on board is the iXRD (developed by Sabanci University) which will provide an improved version of XRD on board BeEagleSat. The leading technology behind iXRD is a CdZnTe-based crystal, operational in the hard X-rays regime, between 20 and 200 keV energy range. The target spectral resolution of the detector is 6 keV at 60 keV. Its' main science goal of the mission is long term monitoring of the brightest galactic X-ray sources, transient and persistent. Black holes and pulsars can emit radiation up to a few 100 keVs making them ideal targets. In addition, hard X-ray spectra from solar flare and coronal holes will be studied. Transient bright events, such as gamma-ray burst (GRB) and magnetar bursts will be studied as well as target of opportunities (TOO). Currently the project is at the Critical Design Review (CDR) level and the anticipated launch is planned for early-to-mid 2021

Comparison of Gaia and Hipparcos parallaxes of close visual binary stars and the impact on determinations of their masses

Precise measurement of the fundamental parameters of stellar systems, including mass and radius, depends critically on how well the stellar distances are known. Astrometry from space provides parallax measurements of unprecented accuracy, from which distances can be derived, initially from the Hipparcos mission, with a further refinement of that analysis provided by van Leeuwen in 2007. The publication of the Gaia DR2 catalogue promises a dramatic improvement in the available data. We have recalculated the dynamical masses of a sample of 1 700 close visual binary stars using Gaia DR2 and compared the results with masses derived from both the original and enhanced Hipparcos data. We show the van Leeuwen analysis yields results close to those of Gaia DR2, but the latter are significantly more accurate. We consider the impact of the Gaia DR2 parallaxes on our understanding of the sample of visual binaries

Human and technological capacity building through the Sharjah-Sat-1 CubeSat project

Sharjah-Sat-1 is 3U+ CubeSat, carrying a primary payload consisting of an X-ray detector to study bright X-ray sources in our Galaxy and a dual camera system as a secondary, remote-sensing application payload. It is the first small satellite mission of the Sharjah Academy for Astronomy, Space Sciences, and Technology (SAASST) and the University of Sharjah (UoS), developed in close collaboration with Istanbul Technical University Space Systems Design and Test Laboratory (ITU-SSDTL) and Sabanci University (SU). Small satellites, especially CubeSat standard, have greatly interested universities and educational establishments due to their lower costs and shorter development time. This makes them ideal for engaging students in the design, testing, and operation of satellite missions and offers a unique first-hand experience in the space industry. The Sharjah-Sat-1 project has provided an essential basis for theoretical and hands-on knowledge of space technologies. This included various extensive workshops for the team of undergraduate students involved and public outreach programs on the topics of satellites and space systems. Additionally, the project has created a solid infrastructure at the Academy to develop further CubeSat missions in the future. Throughout the mission duration, the CubeSat laboratory at SAASST has been expanding and building the necessary facilities that are vital for its success. This includes the high-performance Workstation loaded with the required software to design, simulate and analyze the mission in the space environment, the cleanroom (ISO6 certified) to integrate and test the satellite subsystems, and the ground station (VHF/UHF) needed to communicate with CubeSat once it is in orbit. Furthermore, the participating students have been trained on how to use the software and the operation of the ground station in the scope of the Sharjah-Sat-1 mission. Ultimately, the human and technological capacities the project has built and all experience gained will certainly be transferred to future projects

The iXRD on Sharjah-Sat-1 CubeSat, the science mission, and ground calibration

The Sharjah-Sat-1 3U CubeSat is designed and realized together with the Sharjah Academy for Astronomy, Space Sciences, and Technology (SAASST), the University of Sharjah (UoS), Istanbul Technical University (ITU), and Sabanci University (SU). It has two scientific objectives: performing X-ray astronomy observations and capturing remote sensing and Earth observation images of the United Arab Emirates. The CubeSat is to be launched by the fourth quarter of 2022 and is currently in the Flight-Model integration phase. The primary science payload is the iXRD (Improved X-Ray Detector), with the main objective of observing very bright transient and persistent galactic hard X-ray sources. It will use a pixelated 5 mm CdZnTe-based crystal as an active material with an energy range of 25keV to 300keV and a spectral resolution between 5-10 keV at 60keV, depending on the pixel size. In addition, a Tungsten collimator with a field of view of 4.26 degrees and a tungsten shield at the back decreases the cosmic X-ray and Earth's albedo background. Its' second objective is solar observations to study the hard X-ray spectra of flares and coronal holes. Other potential targets are transient bright events (e.g., GRBs and magnetar bursts). This presentation will show the results of laboratory calibration, TVAC tests, and sensitivity analysis based on in-orbit background simulations to support its science objectives