Kristin K. Madsen
A5016297352- Astrophysical Phenomena and Observations
- Astrophysics and Cosmic Phenomena
- Gamma-ray bursts and supernovae
- Pulsars and Gravitational Waves Research
- Particle Detector Development and Performance
- Galaxies: Formation, Evolution, Phenomena
- Advanced X-ray Imaging Techniques
- High-pressure geophysics and materials
- Astronomical Observations and Instrumentation
- Calibration and Measurement Techniques
- Astronomy and Astrophysical Research
- Advanced Semiconductor Detectors and Materials
- X-ray Spectroscopy and Fluorescence Analysis
- Nuclear Physics and Applications
- Mechanics and Biomechanics Studies
- Adaptive optics and wavefront sensing
- Solar and Space Plasma Dynamics
- Stellar, planetary, and galactic studies
- Particle Accelerators and Free-Electron Lasers
- Dark Matter and Cosmic Phenomena
- Medical Imaging Techniques and Applications
- Surface Roughness and Optical Measurements
- Particle physics theoretical and experimental studies
- Geophysics and Gravity Measurements
- Inertial Sensor and Navigation
Goddard Space Flight Center
2021-2024
National Aeronautics and Space Administration
2024
California Institute of Technology
2014-2023
SpaceX (United States)
2023
University of Maryland, College Park
2023
University of Baltimore
2022
University of Maryland, Baltimore
2022
Kyoto University
2022
University of Maryland, Baltimore County
2021-2022
University of Miyazaki
2022
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...
The Wide-field Infrared Survey Explorer (WISE) is an extremely capable and efficient black hole finder. We present a simple mid-infrared color criterion, W1 − W2 ⩾ 0.8 (i.e., [3.4]−[4.6] ⩾0.8, Vega), which identifies 61.9 ± 5.4 active galactic nucleus (AGN) candidates per deg2 to depth of ∼ 15.0. This implies much larger census luminous AGNs than found by typical wide-area surveys, attributable the fact that selection both unobscured (type 1) obscured 2) AGNs. Optical soft X-ray surveys...
Merging neutron stars offer an exquisite laboratory for simultaneously studying strong-field gravity and matter in extreme environments. We establish the physical association of electromagnetic counterpart EM170817 to gravitational waves (GW170817) detected from merging stars. By synthesizing a panchromatic dataset, we demonstrate that are long-sought production site forging heavy elements by r-process nucleosynthesis. The weak gamma-rays seen dissimilar classical short gamma-ray bursts with...
ABSTRACT We report the detection of coherent pulsations from ultraluminous X-ray source (ULX) NGC 7793 P13. The ≈0.42 s nearly sinusoidal were initially discovered in broadband observations using XMM-Newton and NuSTAR taken 2016. subsequently also found archival data 2013 2014. significant (≫5 σ ) demonstrates that compact object P13 is a neutron star, given observed peak luminosity ≈10 40 <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" overflow="scroll"> <mml:mi>erg</mml:mi>...
We present the calibration of Nuclear Spectroscopic Telescope Array (NuSTAR) X-ray satellite. used Crab as primary effective area calibrator and constructed a piece-wise linear spline function to modify vignetting response. The achieved residuals for all off-axis angles energies, compared assumed spectrum, are typically better than ±2% up 40 keV 5%–10% above due limited counting statistics. An empirical adjustment theoretical two-dimensional point-spread (PSF) was found using several strong...
With the first direct detection of merging black holes in 2015, era gravitational wave (GW) astrophysics began. A complete picture compact object mergers, however, requires an electromagnetic (EM) counterpart. We report ultraviolet (UV) and X-ray observations by Swift Nuclear Spectroscopic Telescope ARray (NuSTAR) EM counterpart binary neutron star merger GW170817. The bright, rapidly fading emission indicates a high mass ($\approx0.03$ solar masses) wind-driven outflow with moderate...
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...
The search for diffuse non-thermal inverse Compton (IC) emission from galaxy clusters at hard X-ray energies has been undertaken with many instruments, most detections being either of low significance or controversial. Background and contamination uncertainties present in the data non-focusing observatories result lower sensitivity to IC a greater chance false detection. We 266ks NuSTAR observations Bullet cluster, detected 3-30 keV. NuSTAR's unprecedented focusing capability largely...
The High Energy X-ray Probe (HEX-P) is a proposed NASA probe-class mission that combines the power of high angular resolution with broad bandpass to provide necessary leap in capabilities address important astrophysical questions next decade. HEX-P achieves breakthrough performance by combining technologies developed experienced international partners. To meet science goals, payload consists suite co-aligned telescopes designed cover 0.2–80 keV bandpass. Telescope (HET) has an effective 2–80...
We report the results of a multi-band observing campaign on famous blazar 3C 279 conducted during phase increased activity from 2013 December to 2014 April, including first observations it with NuSTAR. The $\gamma$-ray emission source measured by Fermi-LAT showed multiple distinct flares reaching highest flux level in this object since beginning Fermi mission, $F(E > 100\,{\rm MeV})$ $10^{-5}$ photons cm$^{-2}$ s$^{-1}$, and doubling time scale as short 2 hours. spectrum one was very hard,...
Using a sample of high-redshift lensed quasars from the CASTLES project with observed-frame ultraviolet or optical and near-infrared spectra, we have searched for possible biases between supermassive black hole (BH) mass estimates based on C iv, Hα, Hβ broad emission lines. Our is upon that Greene, Peng, & Ludwig, expanded new near-IR spectroscopic observations, consistently analyzed high signal-to-noise ratio (S/N) consistent continuum luminosity at 5100 Å. We find BH full width...
The black hole binary Cygnus X-1 was observed in late-2012 with the Nuclear Spectroscopic Telescope Array (NuSTAR) and Suzaku, providing spectral coverage over ~1-300 keV range. source soft state a multi-temperature blackbody, power-law, reflection components along absorption from highly ionized material system. high throughput of NuSTAR allows for very quality measurement complex iron line region as well rest component. is clearly broadened well-described by relativistic blurring model, an...
Stellar metals shine toward our eyes only Taking a different look at familiar star may still yield surprises. Boggs et al. trained the x-ray vision of NuSTAR observatory on well-studied supernova 1987A. Core-collapse explosions such as SN 1987A produce titanium isotope, 44 Ti, whose radioactive decay yields hard emission lines. All associated with 44Ti appears to be from material moving us, none away. This implies that explosion was not symmetric. These findings help explain mechanics and...
We present the results of NuSTAR and XMM-Newton observations two ultraluminous X-ray sources (ULX) NGC 1313 X-1 X-2. The combined spectral bandpass satellites enables us to produce first spectrum between 0.3 30 keV, while X-2 is not significantly detected by above 10 keV. data demonstrate that has a clear cutoff whose presence was only marginally detectable with previous observations. This rules out interpretation as black hole in standard low/hard state, it deeper than predicted for...
ABSTRACT On behalf of the International Astronomical Consortium for High Energy Calibration, we present results from cross-calibration campaigns in 2012 on 3C 273 and 2013 PKS 2155-304 between then active X-ray observatories Chandra , NuSTAR Suzaku Swift, XMM-Newton . We compare measured fluxes instrument pairs two energy bands, 1–5 keV 3–7 keV, calculate an average cross-normalization constant each range. review known features provide a series tables figures to be used evaluating constants...
We present coordinated multiwavelength observations of the bright, nearby BL Lac object Mrk 421 taken in 2013 January-March, involving GASP-WEBT, Swift, NuSTAR, Fermi-LAT, MAGIC, VERITAS, and other collaborations instruments, providing data from radio to very-high-energy (VHE) gamma-ray bands. NuSTAR yielded previously unattainable sensitivity 3-79 keV range, revealing that spectrum softens when source is dimmer until X-ray spectral shape saturates into a steep power law with photon index...
The distribution of elements produced in the inner-most layers a supernova explosion is key diagnostic for studying collapse massive stars. Here we present results 2.4 Ms \textit{NuSTAR} observing campaign aimed at remnant Cassiopeia A (Cas A). We perform spatially-resolved spectroscopic analyses $^{44}$Ti ejecta which use to determine Doppler shift and thus three-dimensional (3D) velocities ejecta. find an initial mass 1.54 $\pm$ 0.21 $\times 10^{-4}$ M$_{\odot}$ has day average momentum...
We present a NuSTAR and XMM-Newton monitoring campaign in 2014/2015 of the Compton-thick Seyfert 2 galaxy, NGC 1068. During August 2014 observation, we detect with flux excess above 20 keV ($32\pm6 \%$) respect to December 2012 observation later performed February 2015. do not any spectral variation below 10 data. The transient can be explained by temporary decrease column density obscuring material along line sight (from N$_{\rm H}\simeq10^{25}$ cm$^{-2}$ H}=6.7\pm1.0\times10^{24}$...
We present results from the coordinated broadband X-ray observations of extreme ultraluminous source Holmberg IX X-1 performed by NuSTAR, XMM-Newton and Suzaku in late 2012. These provide first high-quality spectra above 10 keV to date, extending coverage this remarkable up ~30 keV. Broadband were undertaken at two epochs, between which exhibited both flux strong spectral variability, increasing luminosity Lx = (1.90+/-0.03)e40 erg/s (3.35+/-0.03)e40 erg/s. Neither epoch exhibits a spectrum...
MAXI J1820+070 (optical counterpart ASASSN-18ey) is a black hole candidate discovered through its recent very bright outburst. The low extinction column and long duration at high flux allow detailed measurements of the accretion process to be made. In this work, we compare evolution X-ray spectral timing properties initial hard state We show that inner disc, as measured by relativistic reflection, remains steady throughout period Nevertheless, subtle variability observed, which well...
The hard X-ray emission in active galactic nuclei (AGN) and black hole binaries is thought to be produced by a hot cloud of electrons referred as the corona. This emission, commonly described power law with high-energy cutoff, suggestive Comptonization thermal electrons. While several hypotheses have been proposed explain origin, geometry, composition corona, we still lack clear understanding this fundamental component. NuSTAR has playing key role improving our knowledge coronæ thanks its...
Ever since the discovery of first active galactic nuclei (AGN), substantial observational and theoretical effort has been invested into understanding how massive black holes have evolved across cosmic time. Circum-nuclear obscuration is now established as a crucial component, with almost every AGN observed known to display signatures some level in their X-ray spectra. However, despite more than six decades effort, open questions remain: does accretion power impact structure circum-nuclear...
The <i>Nuclear Spectroscopic Telescope Array (NuSTAR)</i> is a NASA Small Explorer mission that will carry the first focusing hard X-ray (6 - 80 keV) telescope to orbit. <i>NuSTAR</i> offer factor 50 100 sensitivity improvement compared previous collimated or coded mask imagers have operated in this energy band. In addition, provides sub-arcminute imaging with good spectral resolution over 12-arcminute eld of view. After launch, out two-year primary science focuses on four key programs:...