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ART-XC (Astronomical Roentgen Telescope - X-ray Concentrator) is the hard X-ray instrument with grazing incidence imaging optics on board the Spektr-Roentgen-Gamma (SRG) observatory. The SRG observatory is the flagship astrophysical mission…

We make the in-orbit calibration to the point-spread functions (PSFs) of the collimators of the Hard X-ray Modulation Telescope with the scanning observation of the Crab. We construct the empirical adjustments to the theoretically…

Instrumentation and Methods for Astrophysics · Physics 2020-02-05 Yi Nang , Jin-Yuan Liao , Na Sai , Chen Wang , Ju Guan , Cheng-Kui Li , Cheng-Cheng Guo , Yuan Liu , Jing Jin , Xiao-Bo Li , Shu Zhang , Shuang-Nan Zhang

Orthogonal Time Frequency Space (OTFS) modulation offers robust performance in high-mobility scenarios by transforming time-varying channels into the delay-Doppler (DD) domain. However, in high-mobility environment such as emerging 5G…

Information Theory · Computer Science 2026-01-29 Bo-Yuan Chen , Hsuan-Jung Su

We present an untriggered search for optical bursts with the ROTSE-I telephoto array. Observations were taken which monitor an effective 256 square degree field continuously over 125 hours to m_{ROTSE}=15.7. The uniquely large field,…

This paper presents a linear complexity iterative rake detector for the recently proposed orthogonal time frequency space (OTFS) modulation scheme. The basic idea is to extract and coherently combine the received multipath components of the…

Signal Processing · Electrical Eng. & Systems 2021-01-07 Tharaj Thaj , Emanuele Viterbo

Sensors are vital for environmental monitoring, yet their effectiveness diminishes under spatial uncertainty. We propose a robust optimization framework for maximizing the coverage of aerial directional sensors under spatial uncertainty.…

Optimization and Control · Mathematics 2025-10-24 Vanshika Datta , C. Nahak

High-resolution spectroscopy (R>50,000) in astronomy typically uses echelle-type spectrographs, which excel for exoplanet detection via radial velocity but compromise throughput for atmospheric characterization. We propose and test a novel…

Instrumentation and Methods for Astrophysics · Physics 2025-06-18 Casper Farret Jentink , Francesco Pepe , Christophe Lovis , Christian Schwab , François Wildi , Andrew Clawson

Achieving a truly accurate wavelength calibration of high-dispersion echelle spectrographs is a challenging task but crucially needed for certain science cases, e.g. to test for a possible variation of the fine-structure constant in quasar…

Instrumentation and Methods for Astrophysics · Physics 2024-04-09 Tobias M. Schmidt , François Bouchy

Ground-based near-infrared astronomy is severely hampered by the forest of atmospheric emission lines resulting from the rovibrational decay of OH molecules in the upper atmosphere. The extreme brightness of these lines, as well as their…

This paper lays down a proposal of protocol named DREAM_OLSR. The protocol has been developed so as to effect current OLSR (RFC 3626) [4] protocol. The protocol establishes an optimized solution hence the name has been manipulated from Open…

Networking and Internet Architecture · Computer Science 2013-05-15 Gurpreet Singh Saini , Ashish Kots , Manoj Kumar

After the recent approval by the Italian Space Agency (ASI) of the LARES mission, which will be launched at the end of 2008 by a VEGA rocket to measure the general relativistic gravitomagnetic Lense-Thirring effect by combining LARES data…

General Relativity and Quantum Cosmology · Physics 2009-03-07 Lorenzo Iorio

Diffraction gratings with large angular dispersion rates are central to obtaining high spectral resolution in grating spectrometers operating over a broad spectral range from infrared to soft-x-ray domains. The greatest challenge is of…

Optics · Physics 2021-05-18 Yuri Shvyd'ko

We have developed spectral line On-The-Fly (OTF) observing mode for the Nobeyama Radio Observatory 45-m and the Atacama Submillimeter Telescope Experiment 10-m telescopes. Sets of digital autocorrelation spectrometers are available for OTF…

This paper proposes a robust beamforming scheme to enhance the physical layer security (PLS) of multicast transmission in a cognitive satellite and aerial network (CSAN) operating in the millimeter wave frequency band. Based on imperfect…

Signal Processing · Electrical Eng. & Systems 2021-05-14 Bai Zhao , Min Lin , Ming Cheng , Wei-Ping Zhu , Naofal Al-Dhahir

We verified the off-axis jet model of X-ray flashes (XRFs) and examined a discovery of off-axis orphan gamma-ray burst (GRBs) afterglows. The XRF sample was selected on the basis of the following three factors: (1) a constraint on the lower…

High Energy Astrophysical Phenomena · Physics 2015-04-29 Yuji Urata , Kuiyun Huang , Ryo Yamazaki , Takanori Sakamoto

We present a new scheme of a moderate-resolution spectrograph based on a cascade of serial holographic gratings each of which produces an individual spectrum with a resolution of about 6000 and a bandwidth of 80 nm. The gratings ensure…

Instrumentation and Methods for Astrophysics · Physics 2017-01-04 E. R. Muslimov , N. K. Pavlycheva , G. G. Valyavin , S. N. Fabrika

Since the discovery of Gamma-Ray Bursts (GRBs), attempts have been made to detect correlated optical transient emission from these objects. In January 1999, the ROTSE I robotic telescope detected a bright optical flash simultaneous with a…

Astrophysics · Physics 2007-05-23 Eliana Palazzi , Elena Pian

Satellite Laser Ranging (SLR) is an established technology used for geodesy, fundamental science and precise orbit determination. This paper reports on the first successful SLR measurement from the German Aerospace Center research…

Instrumentation and Methods for Astrophysics · Physics 2016-05-25 Daniel Hampf , Fabian Sproll , Paul Wagner , Leif Humbert , Thomas Hasenohr , Wolfgang Riede

The Line Emission Mapper (LEM) is an X-ray Probe with with spectral resolution ~2 eV FWHM from 0.2 to 2.5 keV and effective area >2,500 cm$^2$ at 1 keV, covering a 33 arcmin diameter Field of View with 15 arcsec angular resolution, capable…

Conventional surface-relief gratings are inefficient at deflecting normally-incident light by large angles. This constrains their use in many applications and limits the overall efficiency of any optical instrument integrating gratings.…

Optics · Physics 2021-11-19 Ashutosh Patri , Stephane Kena-Cohen , Christophe Caloz
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