A5061339144- Astrophysical Phenomena and Observations
- Pulsars and Gravitational Waves Research
- Gamma-ray bursts and supernovae
- Astrophysics and Cosmic Phenomena
- High-pressure geophysics and materials
- Geophysics and Gravity Measurements
- Astronomical Observations and Instrumentation
- Solar and Space Plasma Dynamics
- Astro and Planetary Science
- Particle Detector Development and Performance
- Astronomy and Astrophysical Research
- Stellar, planetary, and galactic studies
- Astrophysics and Star Formation Studies
- Mechanics and Biomechanics Studies
- Calibration and Measurement Techniques
- Superconducting Materials and Applications
- Nuclear Physics and Applications
- Dark Matter and Cosmic Phenomena
- Planetary Science and Exploration
- Adaptive optics and wavefront sensing
- Atomic and Subatomic Physics Research
- Advanced Semiconductor Detectors and Materials
- Galaxies: Formation, Evolution, Phenomena
- Optical Systems and Laser Technology
- GNSS positioning and interference
Massachusetts Institute of Technology
2019-2024
Kavli Institute for Particle Astrophysics and Cosmology
2019-2024
Compact Imaging (United States)
2023
McGill University
2017-2020
Columbia University
2011-2016
University of California, Irvine
2016
The Nuclear Spectroscopic Telescope Array (NuSTAR) mission, launched on 2012 June 13, is the first focusing high-energy X-ray telescope in orbit. NuSTAR operates band from 3 to 79 keV, extending sensitivity of far beyond ∼10 keV cutoff achieved by all previous satellites. inherently low background associated with concentrating light enables probe hard sky a more than 100-fold improvement over collimated or coded mask instruments that have operated this bandpass. Using its unprecedented...
Abstract We report Chandra observations of GW170817, the first neutron star–neutron star merger discovered by joint LIGO-Virgo Collaboration, and direct detection gravitational radiation associated with an electromagnetic counterpart, Fermi short γ -ray burst GRB 170817A. The event occurred on 2017 August 17 subsequent identified optical SSS17a, coincident NGC 4993 (∼10″ separation). Early ( days) Swift yielded non-detections at position, but ∼9 days post-trigger monitoring revealed X-ray...
We report the discovery of 3.76 s pulsations from a new burst source near Sgr A* observed by NuSTAR observatory. The strong signal SGR J1745−29 presents complex pulse profile modulated with pulsed fraction 27% ± 3% in 3–10 keV band. Two observations spaced nine days apart yield spin-down rate =(6.5 1.4) × 10−12. This implies magnetic field B = 1.6 1014 G, power =5 1033 erg s−1, and characteristic age P/2 =9 103 yr for rotating dipole model. However, current may be erratic, especially during...
Abstract The origin of the X-ray emission from neutron star coalescence GW170817/GRB 170817A is a key diagnostic unsettled post-merger narrative, and different scenarios predict distinct evolution in its light curve. Due to sky proximity Sun, sensitive monitoring has not been possible since previous detection at 16 days post-burst. We present new, deep Chandra observations 109 post-burst, immediately after Sun constraints were lifted. brightened 0.3–8.0 keV flux erg s −1 cm −2 days, rate...
The Advanced X-ray Imaging Satellite (AXIS) is a Probe-class concept that will build on the legacy of Chandra Observatory by providing low-background, arcsecond-resolution imaging in 0.3-10 keV band across 450 arcminute$^2$ field view, with an order magnitude improvement sensitivity. AXIS utilizes breakthroughs construction lightweight segmented optics using single-crystal silicon, and developments fabrication large-format, small-pixel, high readout rate CCD detectors good spectral...
We present broadband (3–78 keV) NuSTAR X-ray imaging and spectroscopy of the Crab nebula pulsar. show that while phase-averaged spatially integrated + pulsar spectrum is a power law in this energy band, resolved finds break at ∼9 keV spectral photon index torus structure with steepening characterized by ΔΓ ∼ 0.25. also confirm previously reported pulsed spectrum, quantify it broken ∼12 0.27. maps inner 100'' remnant measure size as function seven bands. These results find rate shrinkage can...
We present a wide-field optical imaging search for electromagnetic counterparts to the likely neutron star - black hole (NS-BH) merger GW190814/S190814bv. This compact binary was detected through gravitational waves by LIGO/Virgo interferometers, with masses suggestive of NS-BH merger. imaged localization region using MegaCam instrument on Canada-France-Hawaii Telescope. describe our hybrid observing strategy both tiling and galaxy-targeted observations, as well image differencing transient...
We use the first observation of Betelgeuse in hard $X$-rays to perform a novel search for axion-like particles (ALPs). is not expected be standard source $X$-rays, but light ALPs produced stellar core could converted back into photons Galactic magnetic field, producing detectable flux that peaks $X$-ray band ($E_\gamma>10\mathrm{\,keV}$). Using 50 ks by $NuSTAR$ satellite telescope, we find no significant excess events above background. models regular field direction Betelgeuse, set 95% C.L....
The hard X-ray emission from magnetars and other isolated neutron stars remains under-explored. An instrument with higher sensitivity to X-rays is critical understanding the physics of star magnetospheres also relationship between Fast Radio Bursts (FRBs). High required determine number tails, track transient non-thermal these sources for years post-outburst. This would enable previously impossible studies faint middle-aged rotation-powered pulsars (RPPs), detailed phase-resolved...
We present the first sub-arcminute images of Galactic Center above 10 keV, obtained with NuSTAR. NuSTAR resolves hard X-ray source IGR J17456–2901 into non-thermal filaments, molecular clouds, point sources, and a previously unknown central component emission (CHXE). detects four extending detection their power-law spectra Γ ∼ 1.3–2.3 up to ∼50 keV. A morphological spectral study filaments suggests that origin may be heterogeneous, where previous studies suggested common in young pulsar wind...
We present deep (>2.4 Ms) observations of the Cassiopeia A supernova remnant with NuSTAR, which operates in 3–79 keV bandpass and is first instrument capable spatially resolving above 15 keV. find that emission not entirely dominated by forward shock nor a smooth "bright ring" at reverse shock. Instead we >15 knots near center dimmer filaments remnant's outer rim. These regions are fit unbroken power laws 15–50 bandpass, though central have steeper (Γ ∼ −3.35) spectrum than −3.06). argue...
The multi-wavelength electromagnetic afterglow from the binary neutron star merger GW170817/GRB170817A has displayed long-term power-law brightening, and presented challenges to post-merger models of non-thermal emission. most recent radio observations up 200 days suggest that finally peaked may now be fading, but fading not been confirmed in X-rays. We present new, deep Chandra at 260 reveal an X-ray flux F{0.3-8keV} = 1.1 x 10^-14 erg/s/cm^2, confirm light curve is also fading. Through...
We present the first survey results of hard X-ray point sources in Galactic Center (GC) region by NuSTAR. have discovered 70 (3-79 keV) a 0.6 deg^2 around Sgr A* with total exposure 1.7 Ms, and 7 B2 field 300 ks. identify clear Chandra counterparts for 58 NuSTAR assign candidate remaining 19. The reaches luminosities ~4 x ~8 10^32 erg s^-1 at GC (8 kpc) 3-10 10-40 keV bands, respectively. source list includes three persistent luminous binaries likely run-away pulsar called Cannonball. New...
In 2013, NuSTAR observed the Sgr B2 region and for first time resolved its hard X-ray emission on subarcminute scales. Two prominent features are detected above 10 keV: a newly emerging cloud, G0.66−0.13, central 90'' radius containing two compact cores, B2(M) B2(N), surrounded by diffuse emission. It is inconclusive whether remaining level of still decreasing or has reached constant background level. A can be best explained reflection nebula scenario, where cloud reprocesses past giant...
We present NuSTAR high-energy X-ray observations of the pulsar wind nebula (PWN)/supernova remnant G21.5−0.9. detect integrated emission from up to ∼40 keV, and resolve individual spatial features over a broad band for first time. The morphology seen by agrees well with that XMM-Newton Chandra below 10 keV. At high energies, clearly detects non-thermal ∼20 keV extends along eastern northern rim supernova shell. broadband images demonstrate North Spur Eastern Limb results predominantly...
The Arches cluster is a young, densely packed massive star in our Galaxy that shows high level of formation activity. nature the extended non-thermal X-ray emission around remains unclear. observed bright Fe Kα line at 6.4 keV from material neutral or low ionization state can be produced either by photoionization cosmic-ray particle bombardment both. In this paper, we report on first detection above 10 with NuSTAR mission, and present results its morphology spectrum. spatial distribution...
ABSTRACT Recently, unresolved hard (20–40 keV) X-ray emission has been discovered within the central 10 pc of Galaxy, possibly indicating a large population intermediate polars (IPs). Chandra and XMM-Newton measurements in surrounding ∼50 imply much lighter IPs with <?CDATA $\langle {M}_{{\rm{WD}}}\rangle \approx 0.5{M}_{\odot }$?> . Here we use broadband NuSTAR observations two IPs: TV Columbae, which fairly typical but widely varying reported mass ${M}_{{\rm{WD}}}\approx 0.5$?> –...
Abstract We present a broadband X-ray study of W50 (the “Manatee” nebula), the complex region powered by microquasar SS 433, that provides test bed for several important astrophysical processes. The nebula, Galactic PeVatron candidate, is classified as supernova remnant but has an unusual double-lobed morphology likely associated with jets from 433. Using NuSTAR, XMM-Newton, and Chandra observations inner eastern lobe W50, we have detected hard nonthermal emission up to ∼30 keV, originating...
We report the discovery of ZTF J0127+5258, a compact mass-transferring binary with an orbital period 13.7 minutes. The system contains white dwarf accretor, which likely originated as post-common envelope carbon-oxygen (CO) dwarf, and warm donor ($T_{\rm eff,\,donor}= 16,400\pm1000\,\rm K$). probably formed during common phase between CO evolving giant left behind helium star or in close orbit dwarf. measure gravitational wave-driven inspiral $\sim 35\sigma$ significance, yields joint...
We report the first detection of high-energy X-ray (E > 10 keV) emission from Galactic center non-thermal filament G359.89−0.08 (Sgr A−E) using data acquired with Nuclear Spectroscopic Telescope Array (NuSTAR). The bright was detected up to ∼50 keV during a NuSTAR monitoring campaign. featureless power-law spectrum photon index Γ ≈ 2.3 confirms mechanism. observed flux in 3–79 band is FX = (2.0 ± 0.1) × 10−12 erg cm−2 s−1, corresponding an unabsorbed luminosity LX (2.6 0.8) 1034 s−1 assuming...
HEX-P is a probe-class mission concept that will combine high spatial resolution X-ray imaging ($<10"$ FWHM) and broad spectral coverage (0.2-80 keV) with an effective area far superior to current facilities' (including XMM-Newton NuSTAR). These capabilities enable revolutionary new insights into variety of important astrophysical problems. We present scientific objectives simulations observations the Galactic Center (GC) Bulge. demonstrate unique powerful observatory for studying both point...
NuSTAR is a hard X-ray satellite experiment to be launched in 2012. Two optics with 10.15 m focal length focus Xrays energies between 5 and 80 keV onto CdZnTe detectors located at the end of deployable mast. The FM1 FM2 flight were built same time based on design very similar components, thus performance both expected similar. We provide an overview calibration data that being used build response model for each optic describe initial results above 10 from ground optics. From preliminary...
We analyze the two brightest Chandra X-ray flares detected from Sagittarius A*, with peak luminosities more than 600 x and 245 greater quiescent emission. The flare has a distinctive double-peaked morphology --- it lasts 5.7 ksec ($\sim 2$ hours), rapid rise time of 1500 sec decay 2500 sec. second 3.4 ksec, times 1700 1400 These luminous are significantly harder quiescence: first power law spectral index $\Gamma = 2.06\pm 0.14$ 2.03\pm 0.27$, compared to 3.0\pm0.2$ for accretion flow....