Adam Foster
A5040307838- Astrophysical Phenomena and Observations
- Astrophysics and Cosmic Phenomena
- Gamma-ray bursts and supernovae
- Atomic and Molecular Physics
- Laser-induced spectroscopy and plasma
- X-ray Spectroscopy and Fluorescence Analysis
- Solar and Space Plasma Dynamics
- Galaxies: Formation, Evolution, Phenomena
- Astrophysics and Star Formation Studies
- Stellar, planetary, and galactic studies
- Pulsars and Gravitational Waves Research
- Particle Detector Development and Performance
- Astronomy and Astrophysical Research
- Advanced Materials Characterization Techniques
- Magnetic confinement fusion research
- Advanced X-ray Imaging Techniques
- Mass Spectrometry Techniques and Applications
- Scientific Measurement and Uncertainty Evaluation
- Ionosphere and magnetosphere dynamics
- Astronomical Observations and Instrumentation
- Analytical chemistry methods development
- Fusion materials and technologies
- Nuclear Physics and Applications
- Astro and Planetary Science
- Radioactive Decay and Measurement Techniques
Center for Astrophysics Harvard & Smithsonian
2016-2025
Japan Aerospace Exploration Agency
2016-2024
Institute of Space and Astronautical Science
2024
SRON Netherlands Institute for Space Research
2024
Harvard University
2014-2023
Smithsonian Institution
2023
Smithsonian Astrophysical Observatory
2010-2021
University of Cambridge
2016
Dublin Institute For Advanced Studies
2016
University of Strathclyde
2005-2011
We detect a weak unidentified emission line at E = (3.55–3.57) ± 0.03 keV in stacked XMM-Newton spectrum of 73 galaxy clusters spanning redshift range 0.01–0.35. When the full sample is divided into three subsamples (Perseus, Centaurus+Ophiuchus+Coma, and all others), seen >3σ statistical significance independent MOS spectra PN "all others" spectrum. It also detected Chandra Perseus Cluster. However, it very located within 50–110 eV several known lines. The detection limit current instrument...
We describe the latest release of AtomDB, version 2.0.2, a database atomic data and plasma modeling code with focus on X-ray astronomy. This includes several major updates to fundamental structure process held within incorporating new ionization balance data, state-selective recombination updated collisional excitation for many ions, including iron L-shell ions from Fe$^{+16}$ Fe$^{+23}$ all hydrogen- helium-like sequences. also some effects that these changes have calculated emission...
Despite decades of intense efforts, many fundamental aspects Type Ia supernova (SNe Ia) remain elusive. One the major open questions is whether mass exploding white dwarf (WD) close to Chandrasekhar limit. Here we report detection strong K-shell emission from stable Fe-peak elements in Suzaku X-ray spectrum remnant (SNR) 3C 397. The high Ni/Fe and Mn/Fe ratios (0.11-0.24 0.018-0.033, respectively) hot plasma component that dominates lines indicate a degree neutronization SN ejecta which can...
Abstract High-resolution X-ray spectroscopy with Hitomi was expected to resolve the origin of faint unidentified emission line reported in several low-resolution studies various massive systems, such as galaxies and clusters, including Perseus cluster. We have analyzed first-light observation The for based on XMM-Newton signal from large cluster sample under dark matter decay scenario is too be detectable data. However, previously 3.5 keV flux anomalously high compared sample-based...
The Hitomi SXS spectrum of the Perseus cluster, with $\sim$5 eV resolution in 2-9 keV band, offers an unprecedented benchmark atomic modeling and database for hot collisional plasmas. It reveals both successes challenges current codes. latest versions AtomDB/APEC (3.0.8), SPEX (3.03.00), CHIANTI (8.0) all provide reasonable fits to broad-band spectrum, are close agreement on best-fit temperature, emission measure, abundances a few elements such as Ni. For Fe abundance, APEC measurements...
Abstract We present XRISM Resolve observations of the core hot, relaxed galaxy cluster Abell 2029 (A2029). find that line-of-sight bulk velocity intracluster medium (ICM) within central 180 kpc is at rest with respect to brightest galaxy, a 3 σ upper limit ∣ v < 100 km s −1 . robustly measure field-integrated ICM dispersion be = 169 ± 10 , obtaining similar results for both single-temperature and two-temperature plasma models account cool core. This result, if ascribed isotropic...
The joint JAXA/NASA ASTRO-H mission is the sixth in a series of highly successful X-ray missions initiated by Institute Space and Astronautical Science (ISAS). will investigate physics high-energy universe via suite four instruments, covering very wide energy range, from 0.3 keV to 600 keV. These instruments include high-resolution, high-throughput spectrometer sensitive over 0.3-2 with high spectral resolution Delta E < 7 eV, enabled micro-calorimeter array located focal plane thin-foil...
The joint JAXA/NASA ASTRO-H mission is the sixth in a series of highly successful X-ray missions developed by Institute Space and Astronautical Science (ISAS), with planned launch 2015. equipped suite sensitive instruments highest energy resolution ever achieved at E > 3 keV wide range spanning four decades from soft X-rays to gamma-rays. simultaneous broad band pass, coupled high spectral Delta < 7 eV micro-calorimeter, will enable variety important science themes be pursued. expected...
Abstract We report a systematic search for an emission line around 3.5 keV in the spectrum of cosmic X-ray background using total ∼10 Ms Chandra observations toward COSMOS Legacy and Extended Deep Field South survey fields. find marginal evidence feature at energy ∼3.51 with significance 2.5–3 σ , depending on choice statistical treatment. The intensity is best fit (8.8 ± 2.9) × 10 −7 ph cm −2 s −1 when simple Δ χ 2 or <?CDATA ${10.2}_{-0.4}^{+0.2}\times {10}^{-7}$?> Markov chain Monte Carlo...
The Hitomi (ASTRO-H) mission is the sixth Japanese X-ray astronomy satellite developed by a large international collaboration, including Japan, USA, Canada, and Europe. aimed to provide highest energy resolution ever achieved at E > 2 keV, using microcalorimeter instrument, cover wide range spanning four decades in from soft X-rays gamma-rays. After successful launch on 2016 February 17, spacecraft lost its function March 26, but commissioning phase for about month provided valuable...
Abstract We present an initial analysis of the X-Ray Imaging and Spectroscopy Mission (XRISM) first-light observation supernova remnant (SNR) N 132D in Large Magellanic Cloud. The Resolve microcalorimeter has obtained first high-resolution spectrum 1.6–10 keV band, which contains K-shell emission lines Si, S, Ar, Ca, Fe. find that Si S are relatively narrow, with a broadening represented by Gaussian-like velocity dispersion $\sigma _v \sim 450$ km s$^{-1}$. However, Fe He$\alpha$...
The ubiquitous diffuse soft (1/4 keV) X-ray background was one of the earliest discoveries astronomy. At least some emission may arise from charge exchange between solar wind ions and neutral atoms in heliosphere, but no detailed models have been fit to available data. Here we report on a new model for wind, which when combined with hot plasma component filling Local Cavity provides good only high-resolution extreme ultraviolet (EUV) spectra using plausible parameters wind. implied is...
Arcus will be proposed to the NASA Explorer program as a free-flying satellite mission that enable high-resolution soft X-ray spectroscopy (8-50) with unprecedented sensitivity – effective areas of >500 sq cm and spectral resolution >2500. The key science goals are (1) determine how baryons cycle in out galaxies by measuring effects structure formation imprinted upon hot gas is predicted lie extended halos around galaxies, groups, clusters, (2) black holes influence their surroundings...
Abstract We present an analysis of the first two XRISM/Resolve spectra well-known Seyfert-1.5 active galactic nucleus (AGN) in NGC 4151, obtained 2023 December. Our work focuses on nature narrow Fe K α emission line at 6.4 keV, strongest and most common X-ray observed AGN. The total is found to consist three components. Even narrowest component resolved with evident ,1 (6.404 keV) ,2 (6.391 contributions a 2:1 flux ratio, fully consistent neutral gas negligible bulk velocity. Subject...
We examine high signal-to-noise XMM-Newton European Photon Imaging Camera (EPIC) and Reflection Grating Spectrometer (RGS) observations to determine the physical characteristics of gas in cool core outskirts nearby rich cluster A3112. The Extended Source Analysis Software data reduction background modeling methods were used analyze EPIC data. From data, we find that iron silicon abundance gradients show significant increase toward center while oxygen profile is centrally peaked but has a...
Abstract Charge exchange (CX), both onto ions in the solar wind and potentially other astrophysical contexts, can create X‐ray emission lines largely indistinguishable from those created collisional or photoionized plasmas. The prime distinguishing characteristic is distinctly different line ratios generated by CX process. A complete model of process would require a vast number atomic calculations; we describe here an approximate approach that will allow astronomers to evaluate likely...
The AtomDB project provides models of X-ray and extreme ultraviolet emitting astrophysical spectra for optically thin, hot plasma. We present the new software package, PyAtomDB, which now underpins entire project, providing access to underlying database, collisional radiative model calculations, spectrum generation a range models. PyAtomDB is easily extensible, allowing users build tools use in analysis packages such as XSPEC. two these, kappa ACX non-Maxwellian Charge-Exchange plasmas...
The ITER Scenario Modelling Working Group (ISM WG) is organized within the European Task Force on Integrated Tokamak (ITM-TF). main responsibility of WG to advance a pan-European approach integrated predictive modelling plasmas with emphasis urgent issues, identified during Design Review. Three major topics are discussed, which considered as and where has best possible expertize. These current profile control, density control impurity in (the last two involve both core SOL plasma). Different...
It has been proposed that the charge-exchange (CX) process at interface between hot and cool interstellar gases could contribute significantly to observed soft X-ray emission in star-forming galaxies. We analyze XMM-Newton/reflection grating spectrometer (RGS) spectrum of M82 using a newly developed CX model combined with single-temperature thermal plasma characterize volume-filling gas. The is largely responsible for not only strongly enhanced forbidden lines Kα triplets various He-like...
If the unidentified emission line at ~3.55 keV previously found in spectra of nearby galaxies and galaxy clusters is due to radiatively decaying dark matter, one should detect signal comparable strength from many cosmic objects different nature. By studying existing matter distributions we identified top-19 them observed by XMM-Newton X-ray mission, analyzed data for presence new line. In 8 them, > 2 sigma positive line-like residuals with average position 3.52 +/- 0.08 emitter's frame....
Although collisionless shocks are ubiquitous in astrophysics, certain key aspects of them not well understood. In particular, the process known as electron heating, whereby electrons rapidly energized at shock front, is one main open issues physics. Here we present first clear evidence for efficient heating reverse Tycho's supernova remnant (SNR), revealed by Fe-K diagnostics using high-quality X-ray data obtained Suzaku satellite. We detect K-beta (3p->1s) fluorescence emission from...