What is 3C 324?

We report ground based and HST observations of the z=1.206 radio galaxy 3C 324, a prototypical example of the radio-optical ``alignment effect.'' While infrared images shows a simple, round object reminiscent of a giant elliptical galaxy, the HST images reveal a spectacular, linear chain of UV-bright subcomponents closely aligned with the radio axis. In light of the available data, we consider various scenarios to explain the properties of 3C 324, as well as evidence for the presence of dust which may obscure the central active nucleus and scatter its light to produce the polarized, aligned continuum seen in the rest-frame UV.Comment: 9 pages, uuencoded gzipped postscript. To appear in ``Galaxies in the Young Universe,'' ed. H. Hippelein, Springer Verlag. Revised version (hopefully) corrects postscript error which garbled the last pag

SolSat: A Low-Cost 3-U CubeSat System for Space Weather applications

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Attitude determination and control system of Sharjah-sat-1

Sharjah-Sat-1 is the first CubeSat mission of the Sharjah Academy for Astronomy, Space Sciences, and Technology (SAASST), in collaboration with Istanbul Technical University Space Systems Design and Test Laboratory (ITU-SSDTL) and Sabanci University (SU). The 3U+ CubeSat's primary payload is an improved X-Ray detector (iXRD), with the objectives of detecting hard X-rays from very bright X-ray sources, as well as studying the solar coronal holes. The secondary payload is a dual-camera system for Earth imaging. A dual-camera system will be used to image the SAASST building with a size of about 100m. The iXRD requires an attitude accuracy of 1 degree or better. Its full width at half maximum is 4.26 degrees with a linear response for the square collimator used. Every 1-degree pointing error will lead to 23% information loss. The ADCS subsystem of Sharjah-Sat-1 has been carefully determined and selected to ensure the success of its sophisticated mission, considering the constraints on the CubeSat standards with regards to size, mass, and power, the operational requirements of the mission, and space environmental disturbances expected throughout the mission's lifetime. Those disturbances are mostly encountered at low altitudes, and Sharjah-Sat-1 is planned to have a Sun-synchronous orbit with an altitude of about 500 km, not exceeding 600km. The planned launch date of the mission is June 2022. The paper presents a discussion and evaluation of the ADCS system in detail and its importance in terms of the achievement of the Sharjah-Sat-1 scientific mission (both star/Sun imaging and Earth-imaging), the hardware and the software implemented for active control, and the various attitude determination and control modes for different sensors and actuators' configurations

First light of Sharjah-Sat-1: potential targets and early science

Sharjah-Sat-1 is a 3U+ CubeSat developed as a collaborative research project between the Sharjah Academy for Astronomy, Space Sciences, and Technology (SAASST), University of Sharjah (UoS), Istanbul Technical University (ITU), and Sabanci University (SU). Sharjah-Sat-1 was launched on January 3, 2023, equipped with a dual payload onboard: (i) an improved X-ray Detector (iXRD) and (ii) a system of two optical cameras. Its primary scientific mission is to study bright, hard X-ray sources in our Galaxy and solar coronal holes. The primary science payload onboard is the iXRD (improved X-ray Detector developed by Sabanci University) with CdZnTe-based crystal as the active material and a Tungsten collimator with a field of view of 4 degrees. The energy coverage ranges from 20 keV to 200 keV, with a spectral resolution of 6 keV @ 60 keV. Sharjah-Sat-1 is currently in the commissioning phase, and we anticipate early observation in the next few weeks. Its main science goal is to observe the brightest galactic hard X-ray sources, transient and persistent. Black hole candidates and pulsars emit radiation up to a few 100 keVs, making them potential targets. Long observations of bright Black Hole Candidates will allow observing spectral transition (hard/soft) and studying their variability. Besides, solar observations will be conducted to study hard X-ray spectra of flares and coronal holes. Other targets of opportunity are transient bright events, such as gamma-ray bursts (GRB). While the detector's effective area is only 6.5 cm2, it is expected to reach a sensitivity of around 60 mCrab in a single day in the 20 keV to 100 keV band, assuming 600s exposure for each orbit. However, further in-flight calibrations are needed. By the time of the conference, we anticipate having and presenting the first high-level products (i.e., spectra and lightcurves) of the brightest X-ray galactic sources (e.g., Cyg X-1, Sco X-1, etc.) observed by Sharjah-Sat-1

Sharjah-Sat-3: A Low-Cost 6U CubeSat for Space Weather Applications

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