S. D. Sidher
A5106716247- Astro and Planetary Science
- Stellar, planetary, and galactic studies
- Astrophysics and Star Formation Studies
- Solar and Space Plasma Dynamics
- Astronomy and Astrophysical Research
- Planetary Science and Exploration
- Astronomical Observations and Instrumentation
- Astrophysical Phenomena and Observations
- Atmospheric Ozone and Climate
- Spectroscopy and Laser Applications
- Calibration and Measurement Techniques
- Space Exploration and Technology
- Galaxies: Formation, Evolution, Phenomena
- Astrophysics and Cosmic Phenomena
- GNSS positioning and interference
- Adaptive optics and wavefront sensing
- Atomic and Molecular Physics
- X-ray Spectroscopy and Fluorescence Analysis
- Superconducting and THz Device Technology
- Dark Matter and Cosmic Phenomena
- Geophysics and Gravity Measurements
- Advanced X-ray Imaging Techniques
- Ionosphere and magnetosphere dynamics
- Radar Systems and Signal Processing
- Modeling, Simulation, and Optimization
Rutherford Appleton Laboratory
2008-2023
Imperial College London
1992-2008
Science and Technology Facilities Council
1999
The first all-sky survey for cosmic sources of extreme-ultraviolet radiation has been carried out with the UK Wide Field Camera on ROSAT. A reduction data yielded a catalogue 383 relatively bright EUV sources, forming WFC Bright Source Catalogue. This represents 30-fold increase in number astrophysical objects detected ~ 60–200 eV energy band and covers flux range, each two bands, more than 2000. search (typically 1-arcmin) error circles using variety catalogues SIMBAD base, identified...
Herschel-PACS measurements of the rotational R(0) and R(1) HD lines in atmospheres Uranus Neptune are analyzed order to derive a D/H ratio with improved precision for both planets. The derivation includes also previous R(2) line by Short Wavelength Spectrometer on board Infrared Space Observatory (ISO). available spectroscopic information three transitions is discussed applied radiative transfer calculations. best simultaneous fit all requires only minor departure from Spitzer temperature...
The Herschel SPIRE instrument consists of an imaging photometric camera and Fourier Transform Spectrometer (FTS), both operating over a frequency range 450-1550 GHz. In this paper, we briefly review the FTS design, operation, data reduction, describe in detail approach taken to relative calibration (removal signatures) absolute against standard astronomical sources. scheme assumes spatially extended source uses telescope as primary calibrator. Conversion from point-source is carried out...
Context. To meet the scientific objectives of mission, Solar Orbiter spacecraft carries a suite in-situ (IS) and remote sensing (RS) instruments designed for joint operations with inter-instrument communication capabilities. Indeed, previous missions have shown that Sun (imaged by RS instruments) heliosphere (mainly sampled IS should be considered as an integrated system rather than separate entities. Many advances expected from rely on this synergistic approach between measurements. Aims....
Aims. We present an analysis of the first connection mosaic made by SPICE instrument on board ESA/NASA Solar Orbiter mission March 2, 2022. The data will be used to map coronal composition that compared with in-situ measurements taken SWA/HIS establish origin solar wind plasma observed at Orbiter. spectral lines were chosen have varying sensitivity ionization potential (FIP) effect, and therefore radiances vary significantly depending whether elemental is or photospheric. investigate link...
SPIRE, the Spectral and Photometric Imaging Receiver, is a submillimetre camera spectrometer for Herschel. It comprises three-band operating at 250, 350 500 µm, an imaging Fourier Transform Spectrometer covering 194-672 μm. The photometer field of view 4x8 arcmin., viewed simultaneously in three bands. FTS has approximately circular 2.6 arcmin. diameter spectral resolution adjustable between 0.04 2 cm<sup>-1</sup> ( λ/▵λ=20-1000 250 μm). Following successful testing...
Abstract The Slow Solar Wind Connection Orbiter Observing Plan (Slow SOOP) was developed to utilize the extensive suite of remote-sensing and in situ instruments on board ESA/NASA mission answer significant outstanding questions regarding origin formation slow solar wind. SOOP designed link measurements wind originating at open–closed magnetic field boundaries. ran just prior Orbiter’s first close perihelion passage during two windows (RSW1 RSW2) between 2022 March 3–6 17–22, while...
Context. The Solar Orbiter mission completed its first remote-sensing observation windows in the spring of 2022. On 2 April 2022, an M-class flare followed by a filament eruption was seen both instruments on board and from several observatories Earth’s orbit, providing unprecedented view flaring region with large range observations. Aims. We aim to understand nature events via analysis available dataset. complexity observed features is compared predictions given standard model 3D. Methods....
The Spectral and Photometric Imaging Receiver (SPIRE) is one of three scientific instruments onboard the European Space Agency's Herschel Observatory launched on 14 May 2009. low to medium resolution spectroscopic capability SPIRE provided by an imaging Fourier transform spectrometer Mach-Zehnder configuration. Results from in flight performance verification phase are presented conformance with instrument design specifications reviewed.
A key goal of the Solar Orbiter mission is to connect elemental abundance measurements solar wind enveloping spacecraft with EUV spectroscopic observations their sources, but this not an easy exercise. Observations from previous missions have revealed a highly complex picture spatial and temporal variations abundances in corona. We used coordinated Hinode attempt new SPICE (Spectral Imaging Coronal Environment) instrument, benchmark them against standard analyses EIS (EUV Spectrometer). use...
We have obtained the first continuous disk averaged spectrum of Mars from 450 to 1550 Ghz using <i>Herschel<i/>-SPIRE Fourier-transform spectrometer. The was at a constant resolution 1.4 GHz across whole band. flux planet is such that instrument operated in "bright source" mode prevent saturation detectors. This successful use this and work we describe method used for observing together with detailed discussion data reduction techniques required calibrate spectrum. discuss calibration...
We announce the detection of flaring activity from a stellar source not previously known to be coronally active. The was detected with ROSAT Wide Field Camera during All Sky Survey stage satellite mission. A long-duration flare lasting for |$\sim 12000 \ {\rm s}$| observed low-energy survey filter, followed by period enhanced about 20 h. Optical observations have identified as an active K0V star, HD 197890. Spectral measurements found Ca ii emission core FWHM linewidths corresponding...
view Abstract Citations (7) References (28) Co-Reads Similar Papers Volume Content Graphics Metrics Export Citation NASA/ADS ROSAT Wide Field Camera Minisurvey of the Diffuse Sky Background in 90--188 eV Soft X-Rays Lieu, R. ; Quenby, J. Sidher, S. D. Sumner, T. Willingale, West, G. Harris, A. W. Snowden, L. Bickert, K. We present observations diffuse soft X-ray background band between 90 and 188 made by (WFC) on ROSAT. The were during a 5-day period prior to main all-sky survey cover great...
A key goal of the Solar Orbiter mission is to connect elemental abundance measurements solar wind enveloping spacecraft with EUV spectroscopic observations their sources, but this not an easy exercise. Observations from previous missions have revealed a highly complex picture spatial and temporal variations abundances in corona. We used coordinated Hinode attempt new SPICE (Spectral Imaging Coronal Environment) instrument, benchmark them against standard analyses EIS (EUV Spectrometer). use...