Brian D. Ramsey
A5055588693- Astrophysical Phenomena and Observations
- Particle Detector Development and Performance
- Advanced X-ray Imaging Techniques
- Astrophysics and Cosmic Phenomena
- Gamma-ray bursts and supernovae
- Nuclear Physics and Applications
- Pulsars and Gravitational Waves Research
- Radiation Detection and Scintillator Technologies
- Advanced X-ray and CT Imaging
- X-ray Spectroscopy and Fluorescence Analysis
- High-pressure geophysics and materials
- Calibration and Measurement Techniques
- Astronomical Observations and Instrumentation
- Solar and Space Plasma Dynamics
- Advanced Semiconductor Detectors and Materials
- Adaptive optics and wavefront sensing
- Atomic and Subatomic Physics Research
- Mechanics and Biomechanics Studies
- Particle Accelerators and Free-Electron Lasers
- Medical Imaging Techniques and Applications
- Planetary Science and Exploration
- Advanced Surface Polishing Techniques
- Astronomy and Astrophysical Research
- Dark Matter and Cosmic Phenomena
- Spacecraft Design and Technology
Marshall Space Flight Center
2015-2024
National Energy Technology Laboratory
2022
Deloitte (United Kingdom)
2022
Smithsonian Astrophysical Observatory
2005-2018
Lawrence Livermore National Laboratory
2005-2018
Sandia National Laboratories
2018
Universities Space Research Association
2018
Nagoya University
2010-2016
National Space Science and Technology Center
2003-2014
Kavli Institute for Particle Astrophysics and Cosmology
2010
The IBIS telescope is the high angular resolution gamma-ray imager on-board INTEGRAL Observatory, successfully launched from Baikonur (Kazakhstan) 17th of October 2002. This medium size ESA project, planned for a 2 year mission with possible extension to 5, devoted observation sky in energy range 3 keV 10 MeV (Winkler [CITE]). imaging system based on two independent solid state detector arrays optimised low ( keV) and MeV) energies surrounded by an active VETO System. efficiency shield...
Launched on 2021 December 9, the Imaging X-ray Polarimetry Explorer (IXPE) is a NASA Small Mission in collaboration with Italian Space Agency (ASI). The mission will open new window of investigation—imaging x-ray polarimetry. observatory features three identical telescopes, each consisting mirror module assembly polarization-sensitive imaging detector at focus. A coilable boom, deployed orbit, provides necessary 4-m focal length. utilizes three-axis-stabilized spacecraft, which services such...
Astronomical Roentgen Telescope – X-ray Concentrator (ART-XC) is the hard instrument with grazing incidence imaging optics on board Spektr-Roentgen-Gamma (SRG) observatory. The SRG observatory flagship astrophysical mission of Russian Federal Space Program, which was successively launched into orbit around second Lagrangian point (L2) Earth-Sun system a Proton rocket from Baikonur cosmodrome 13 July 2019. ART-XC telescope will provide first ever true all-sky survey performed in 4–30 keV...
A black hole x-ray binary (XRB) system forms when gas is stripped from a normal star and accretes onto hole, which heats the sufficiently to emit x-rays. We report polarimetric observation of XRB Cygnus X-1 using Imaging Polarimetry Explorer. The electric field position angle aligns with outflowing jet, indicating that jet launched inner emitting region. polarization degree (4.01+-0.20)% at 2 8 kiloelectronvolts, implying accretion disk viewed closer edge-on than orbit. observations reveal...
Abstract Imaging X-ray Polarimetry Explorer (IXPE) is a Small mission by NASA and Agenzia Spaziale Italiana, launched on 2021 December 9, dedicated to investigating polarimetry allowing angular-, time-, energy-resolved observations in the 2–8 keV energy band. IXPE science observation phase since 2022 January; it comprised of three identical telescopes with grazing-incidence mirrors, each one having focal plane gas pixel detector. In this paper, we present possible guideline obtain an optimal...
ABSTRACT We present an X-ray spectropolarimetric analysis of the bright Seyfert galaxy NGC 4151. The source has been observed with Imaging Polarimetry Explorer (IXPE) for 700 ks, complemented simultaneous XMM–Newton (50 ks) and NuSTAR (100 pointings. A polarization degree Π = 4.9 ± 1.1 per cent angle Ψ 86° 7° east north (68 confidence level) are measured in 2–8 keV energy range. shows that could be entirely due to reflection. Given low reflection flux IXPE band, this requires, however, a...
The Imaging X-ray Polarimetry Explorer (IXPE) expands observation space by simultaneously adding polarization measurements to the array of source properties currently measured (energy, time, and location). IXPE will thus open new dimensions for understanding how emission is produced in astrophysical objects, especially systems under extreme physical conditions—such as neutron stars black holes. Polarization singularly probes anisotropies—ordered magnetic fields, aspheric matter...
Due to be launched in late 2021, the Imaging X-Ray Polarimetry Explorer (IXPE) is a NASA Small mission designed perform polarization measurements 2-8 keV band, complemented with imaging, spectroscopy and timing capabilities. At heart of focal plane set three polarization-sensitive Gas Pixel Detectors (GPD), each based on custom ASIC acting as charge-collecting anode. In this paper we shall review design, manufacturing, test IXPE focal-plane detectors, particular emphasis connection between...
IXPE is a Small Explorer mission that was launched at the end of 2021 to measure polarization X-ray emission from tens astronomical sources. Its focal plane detectors are based on Gas Pixel Detector, which measures by imaging photoelectron tracks in gas mixture and reconstructing their initial directions. The quality single track, then capability correctly determining original direction photoelectron, depends many factors, e.g., whether emitted low or high inclination with respect collection...
Abstract Particle acceleration mechanisms in supermassive black hole jets, such as shock acceleration, magnetic reconnection, and turbulence, are expected to have observable signatures the multiwavelength polarization properties of blazars. The recent launch Imaging X-Ray Polarimetry Explorer (IXPE) enables us, for first time, use X-ray band (2–8 keV) probe jet synchrotron emission high-synchrotron-peaked BL Lac objects (HSPs). We report discovery linear (degree Π x = 15% ± 2% electric...
We report on the first detection of linearly polarized x-ray emission from an ultra-magnetized neutron star with Imaging X-ray Polarimetry Explorer (IXPE). The IXPE 35 observations anomalous pulsar 4U 0142+61 reveal a linear polarization degree $(12\pm 1)\%$ throughout 2--8 keV band. detect substantial variation energy: is $(14\pm at 2--4 and $(41\pm 7)\%$ 5.5--8 keV, while it drops below instrumental sensitivity around 4--5 where angle swings by $\sim 90^\circ$. give us completely new...
Abstract We report the first detection of X-ray polarization bright transient Swift J1727.8−1613 with Imaging Polarimetry Explorer. The observation was performed at beginning 2023 discovery outburst, when source resided in hard state. find a time- and energy-averaged degree 4.1% ± 0.2% angle 2.°2 1.°3 (errors 68% confidence level; this translates to ∼20 σ significance detection). This finding suggests that hot corona emitting bulk detected X-rays is elongated, rather than spherical....
Abstract We present the IXPE observation of GRB 221009A, which includes upper limits on linear polarization degree both prompt and afterglow emission in soft X-ray energy band. 221009A is an exceptionally bright gamma-ray burst (GRB) that reached Earth 2022 October 9 after traveling through dust Milky Way. The Imaging Polarimetry Explorer (IXPE) pointed at 11 to observe, for first time, 2–8 keV a afterglow. set limit 13.8% 99% confidence level. This result provides constraints jet opening...
Abstract The lower-energy peak of the spectral energy distribution blazars has commonly been ascribed to synchrotron radiation from relativistic particles in jets. Despite consensus regarding jet emission processes, particle acceleration mechanism is still debated. Here, we present first X-ray polarization observations PG 1553+113, a high-synchrotron-peak blazar observed by Imaging Polarimetry Explorer (IXPE). We detect an degree (10 ± 2)% along electric-vector position angle ψ X = 86° 8°....
ABSTRACT We present an X-ray spectro-polarimetric analysis of the bright Seyfert galaxy IC 4329A. The Imaging Polarimetry Explorer (IXPE) observed source for ∼500 ks, supported by XMM–Newton (∼60 ks) and NuSTAR (∼80 exposures. detect polarization in 2–8 keV band with 2.97σ confidence. report a degree 3.3 ± 1.1 per cent angle 78° 10° (errors are 1σ confidence). is consistent being aligned radio jet, albeit partially due to large uncertainties on position angle. jointly fit spectra from three...
After about 16 years since its first outburst, the transient neutron star low-mass X-ray binary XTE J1701$-$462 turned on again in September 2022, allowing for study of polarimetric characteristics by a dedicated observing program with Imaging Polarimeter Explorer (IXPE). Polarimetric studies have been expected to improve our understanding accreting weakly magnetized stars, particular, physics and geometry hot inner regions close compact object. The IXPE data two triggered observations were...
Abstract The launch of the Imaging X-ray Polarimetry Explorer (IXPE) on 2021 December 9 has opened a new window in astronomy. We report here results first IXPE observation weakly magnetized neutron star, GS 1826−238, performed 2022 March 29–31 when source was high soft state. An upper limit (99.73% confidence level) 1.3% for linear polarization degree is obtained over 2–8 keV energy range. Coordinated INTEGRAL and NICER observations were carried out simultaneously with IXPE. spectral...
Abstract A large energy-dependent X-ray polarization degree is detected by the Imaging Polarimetry Explorer (IXPE) in high-soft emission state of black hole binary 4U 1630–47. The highly significant detection (at ≈50 σ confidence level) an unexpectedly high polarization, rising from ∼6% at 2 keV to ∼10% 8 keV, cannot be easily reconciled with standard models thin accretion disks. In this work, we compare predictions different theoretical IXPE data and conclude that observed properties are...
Abstract The Imaging X-ray Polarimetry Explorer measured with high significance the polarization of brightest Z-source, Sco X-1, resulting in nominal 2–8 keV energy band a degree 1.0% ± 0.2% and angle 8° 6° at 90% confidence level. This observation was strictly simultaneous observations performed by NICER, NuSTAR, Insight-HXMT, which allowed for precise characterization its broadband spectrum from soft to hard X-rays. source has been observed mainly state, short periods flaring. We also...
We present the results of first X-ray polarimetric observation low-mass binary 4U 1957+115, performed with Imaging Polarimetry Explorer in May 2023. The system has been a high-soft spectral state since its discovery and is thought to host black hole. ∼571 ks reveals linear polarisation degree 1.9%±0.6% angle −41.°8±7.°9 2–8 keV energy range. Spectral modelling consistent dominant contribution coming from standard accretion disc, while data suggest significant role returning radiation:...
Abstract Cir X-1 is a neutron star X-ray binary characterized by strong variations in flux during its eccentric ∼16.6 day orbit. There are also the spectral state, and it has historically shown both atoll Z state properties. We observed source with Imaging Polarimetry Explorer two orbital segments, 6 days apart, for total of 263 ks. find an polarization degree these segments 1.6% ± 0.3% 1.4% at angles 37° 5° −12° 7°, respectively. Thus, we rotation angle 49° 8° along Because accretion flow,...