A5064154817- Astrophysical Phenomena and Observations
- Galaxies: Formation, Evolution, Phenomena
- Astrophysics and Cosmic Phenomena
- Particle accelerators and beam dynamics
- Astronomy and Astrophysical Research
- Pulsars and Gravitational Waves Research
- Particle Accelerators and Free-Electron Lasers
- Gamma-ray bursts and supernovae
- Stellar, planetary, and galactic studies
- Gyrotron and Vacuum Electronics Research
- Adaptive optics and wavefront sensing
- Astronomical Observations and Instrumentation
- Electromagnetic Launch and Propulsion Technology
- Pulsed Power Technology Applications
- Mechanics and Biomechanics Studies
- Astrophysics and Star Formation Studies
- Superconducting Materials and Applications
- Magnetic confinement fusion research
- Laser-Plasma Interactions and Diagnostics
- Geophysics and Gravity Measurements
- High-pressure geophysics and materials
- Distributed and Parallel Computing Systems
- Radiation Detection and Scintillator Technologies
- Advanced X-ray Imaging Techniques
- Radio Astronomy Observations and Technology
High Magnetic Field Laboratory
2024-2025
Bristol Robotics Laboratory
2011-2024
University of Bristol
2012-2024
Lawrence Livermore National Laboratory
2012-2024
University of Arizona
2022-2024
SLAC National Accelerator Laboratory
1998-2022
Texas Tech University
2006-2011
Carleton College
2010
Massachusetts Institute of Technology
2005-2008
Kavli Institute for Particle Astrophysics and Cosmology
2007-2008
An intrinsically narrow line emitted by an accretion disk around a black hole appears broadened and skewed as result of the Doppler effect gravitational redshift. The fluorescent iron in X‐ray band at 6.4–6.9 keV is strongest such seen spectrum many active galactic nuclei and, particular, Seyfert galaxies. It important diagnostic with which to study geometry other properties flow very close central hole. broad indicates presence standard thin those objects, often low inclination. has opened...
We present the first results from a 325-ks observation of Seyfert 1 galaxy MCG–6-30-15 with XMM-Newton and BeppoSAX. The strong, broad, skewed iron line is clearly detected well characterized by steep emissivity profile within 6rg (i.e. 6GM/c2) flatter beyond. inner radius emission appears to lie at about 2rg, consistent reported both an earlier Wilms et al. part ASCA Iwasawa when source was in lower flux state. do depend however on assumed incident power-law continuum lack complex...
Chandra X-ray observations of the giant elliptical galaxy M87 resolve thermal state hot interstellar medium into accretion (Bondi) radius its central 3 × 109 M☉ black hole. We measure gas temperature and density profiles calculate Bondi rate, ~ 0.1 yr-1. The luminosity active nucleus observed with is LX,0.5-7 keV 7 1040 ergs s-1. This value much less than predicted nuclear luminosity, LBondi 5 1044 s-1, for at rate a canonical radiative efficiency 10%. If hole in accretes this it must do so...
Results are presented from a 500ks long XMM-Newton observation of the Narrow-Line Seyfert 1 galaxy IRAS13224-3809. The source is rapidly variable on timescales down to few 100s. spectrum shows strong broad Fe-K and L emission features which interpreted as arising reflection inner parts an accretion disc around spinning black hole. Assuming power-law emissivity for reflected flux that innermost radius corresponds stable circular orbit, hole spin measured be 0.988 with statistical precision...
X-ray reflection spectra are an important component in the of many active galactic nuclei and Galactic black hole candidates. It is likely that takes place from highly ionized surfaces accretion disc some cases. This can lead to strong Comptonization emergent iron, other absorption emission features. We present such here, computed a self-consistent manner with method described by Ross & Fabian. In particular we emphasize range where ionization parameter (the flux density ratio) ξ around...
We report X-ray observations of the nearby, powerful radio galaxy Pictor A with Chandra Observatory and optical near-UV its western hot spot Hubble Space Telescope. emission is detected from nucleus, a 19 (110 kpc) long jet to west some 42 (240 eastern lobe. The morphology remarkably similar that seen at wavelengths, where known be synchrotron radiation. spectrum well described by an absorbed power law photon index Γ = 2.07 ± 0.11. coincides weak laterally extended ≃20 (1.9 kpc). observed up...
Abstract We present numerical simulations investigating the interaction of active galactic nucleus jets with galaxy clusters, for first time taking into account dynamic nature cluster gas and detailed physics. The successfully reproduce observed morphologies radio sources in clusters. find that inhomogeneities large-scale flows have a significant impact on morphology source cannot be ignored priori when dynamics. Morphological comparison suggests centres clusters like Virgo Abell 4059 shows...
We measure X-ray emission from the outskirts of cluster galaxies PKS 0745-191 with Suzaku, determining radial profiles density, temperature, entropy, gas fraction, and mass. These measurements extend beyond virial radius for first time, providing new information about assembly diffuse intracluster medium out to ~1.5 r_200, (r_200 ~ 1.7 Mpc 15'). The temperature is found decrease by roughly 70 per cent 0.3-1 r_200. also see a flattening entropy profile near consider implications this has...
We present the results of a broadband simultaneous campaign on nearby low-luminosity active galactic nucleus M81*. From February through August 2005, we observed M81* five times using Chandra X-ray Observatory with High-Energy Transmission Grating Spectrometer, complemented by ground-based observations Giant Meterwave Radio Telescope, Very Large Array and Baseline Array, Plateau de Bure Interferometer at IRAM, Submillimeter Lick Observatory. discuss how resulting spectra vary over short...
We present new Chandra images of the X-ray emission from core Perseus cluster galaxies. The total observation time is now 1.4 Ms. New depressions in surface brightness are discovered to north NGC1275, which we interpret as old rising bubbles. They imply that bubbles long-lived and do not readily breakup when hot atmosphere. existence a 300 kpc long NNW-SSW bubble axis means there cannot be significant transverse large scale flows exceeding 100 km/s. Interesting spatial correlations seen...
We present a detailed X-ray timing analysis of the highly variable NLS1 galaxy, IRAS 13224-3809. The source was recently monitored for 1.5 Ms with XMM-Newton which, combined 500 ks archival data, makes this best studied galaxy in X-rays to date. apply standard time- and Fourier-domain order understand underlying variability process. flux is not distributed lognormally, as would be expected accreting sources. first non-linear rms-flux relation any waveband found, $\mathrm{rms} \propto...
The relativistically broad X-ray iron line seen in many active galactic nucleus (AGN) spectra is thought to originate from the central regions of putative black hole accretion disk. Both profile and strength will vary response rapid variability primary continuum source. temporal contains information on disk structure, source geometry, spin hole. Since have a size comparable with fluorescing region disk, general reverberation problem not invertible. However, progress can be made, since,...
We report sub arc-second resolution X-ray imaging-spectroscopy of the archetypal type 2 Seyfert galaxy NGC 1068 with Chandra Observatory. The observations reveal detailed structure and spectra 13 kpc-extent nebulosity previously imaged at lower ROSAT. image shows a bright, compact source coincident brightest radio optical emission; this is extended by \simeq 1.5 arcsec (165 pc) in same direction as nuclear line continuum emission. Bright emission extends 5 (550 to NE coincides lobe gas...
We report sub-arcsecond X-ray imaging spectroscopy of M87 and the core Virgo cluster with Chandra Observatory. The morphology shows structure on arcsecond (~100 pc) to ten arcminute (~50 kpc) scales, most prominent feature being an "arc" running from east, across central region off southwest. A ridge in radio map, ending "ear"-shaped structure, follows arc east. Depressions surface brightness correspond inner lobes there is no evidence shock-heated gas surrounding them. There are also at...
The results from a recent Chandra ACIS-S study of the cluster surrounding Cygnus A are presented. We have deprojected X-ray spectra taken various elliptical shells in order to derive run temperature, density, pressure, and abundance for ICM as function radius. confirm drop temperature emitting gas $\sim 8$ keV more than 2^{\prime}$ center $\simeq 5$ some $30^{\prime\prime}$ center, with coolest immediately adjacent radio galaxy. ``Belts'' slightly cooler ($\simeq 4$ keV) around minor...
We report X-ray observations of the powerful radio galaxy Cygnus A with Chandra Observatory. This letter focuses on hot spots, all four which are detected in X-rays a very similar morphology to their structure. spectra have been obtained for two brighter spots (A and D). Both well described by power law photon index Γ= 1.8 \pm 0.2 absorbed Galactic column direction A. Thermal models require too high gas densities may be ruled out. The images strongly support synchrotron self-Compton...
We use 2.0 Msec of Chandra observations to investigate the cocoon shocks Cygnus A and some implications for its lobes jet. Measured shock Mach numbers vary in range 1.18-1.66 around cocoon. estimate a total outburst energy $\simeq 4.7\times10^{60}\rm\ erg$, with an age 2 \times 10^{7}\rm\ yr$. The average postshock pressure is found be $8.6 \pm 0.3 10^{-10}\rm\ erg\ cm^{-3}$, which agrees thin rim compressed gas between radio shocks, as determined from X-ray spectra. However, pressures are...
We report results on the broad iron emission line of Seyfert galaxy MCG-6-30-15, obtained from second long ASCA observation in 1997. The time-averaged profile is very similar to that seen with 1994, so confirming detailed model fit then obtained. A bright flare light curve, during which continuum was soft. At time peaks around 5 keV and most its shifted below 6 no component detected at 6.4 (EW < 60eV). This can be interpreted as result an extraordinarily large gravitational redshift owing a...
We present a high resolution X-ray spectrum of the iron K bandpass in MCG-6-30-15 based on 522 ksec observation with Chandra's High Energy Transmission Grating Spectrometer. The Chandra is consistent presence relativistically broadened, highly redshifted alpha emission line similar profile to previous observations. A number narrow features are detected above 2 keV, including Fe and absorption lines from H- He-like Fe, H-like S Si. This well described by photoionized plasma column density log...
In this Letter, we focus on the limb-brightened, prolate spheroidal cavity of radio galaxy Cygnus A, as revealed by Chandra X-Ray Observatory. We use shock-heated, thermal intracluster medium around expanding to infer properties synchrotron-emitting gas inside cavity. The along north and south edges is found have an average temperature 6.0 keV, which hotter than (4.6 keV) adjacent gas. It proposed that shocked shock thus inferred be weak (Mach number 1.3, a value also from density jump at...
General relativistic ray tracing simulations of the time-averaged spectrum and energy-dependent time delays in active galactic nuclei (AGN) are presented. We model lamp-post geometry which accreting gas is illuminated by an X-ray source located on rotation axis black hole. The spectroscopic features imprinted reflection component modelled using reflionx. associated after direct continuum, known as reverberation lags, computed including full effects dilution ionization gradients disc....
We study the X-ray reverberation in active galactic nuclei (AGN) using variational autoencoder (VAE), which is a machine-learning algorithm widely used for signal processing and feature reconstruction. While signatures that contain information of accretion disk emitting corona are commonly analyzed Fourier domain, this work aims to extract response functions directly from AGN light curves. The VAE trained simulated curves primary X-rays lamp-post varying its height corresponding reflection...
This paper presents a novel approach to addressing challenges in neutrino event reconstruction within large Time Projection Chambers (TPCs). By integrating fiber-coupled digital silicon photomultipliers, we propose design that enhances light detection, improves energy resolution, and enhance reconstruction. Advancements power signal over fiber technologies are leveraged deploy sensors the TPC bulk volume, enabling precise timing robust particle identification.