Fiona A. Harrison - Caltech

Fiona A. Harrison
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Fiona A. Harrison
United States

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High Energy Astrophysical Phenomena (44)
Astrophysics of Galaxies (15)
Instrumentation and Methods for Astrophysics (5)
Solar and Stellar Astrophysics (3)
Cosmology and Nongalactic Astrophysics (3)
Earth and Planetary Astrophysics (1)

Publications Authored By Fiona A. Harrison

Affiliations: 1SSL/UCB, 2Cambridge, 3Harvard, 4SSL/UCB, 5Harvard-Smithsonian CfA, 6Harvard-Smithsonian CfA, 7Cambridge, 8Univ. of Durham, 9Georgia College, 10SSL/UCB, 11Harvard-Smithsonian CfA, 12Columbia, 13Caltech, 14Space Research Institute, Russian Academy of Sceinces, 15Columbia, 16JPL

The Nuclear Spectroscopic Telescope Array (NuSTAR) provides an improvement in sensitivity at energies above 10 keV by two orders of magnitude over non-focusing satellites, making it possible to probe deeper into the Galaxy and Universe. Lansbury and collaborators recently completed a catalog of 497 sources serendipitously detected in the 3-24 keV band using 13 deg2 of NuSTAR coverage. Here, we report on an optical and X-ray study of 16 Galactic sources in the catalog. Read More

Understanding the origin of the flaring activity from the Galactic center supermassive black hole, Sagittarius A*, is a major scientific goal of the NuSTAR Galactic plane survey campaign. We report on the data obtained between July 2012 and April 2015, including 27 observations on Sgr A* with a total exposure of ~ 1 Ms. We found a total of ten X-ray flares detected in the NuSTAR observation window, with luminosities in the range of $L_{3-79~keV}$~$(0. Read More

We study the observed relation between accretion rate (in terms of L/L_Edd) and shape of the hard X-ray spectral energy distribution (namely the photon index Gamma_X) for a large sample of 228 hard X-ray selected, low-redshift active galactic nuclei (AGN), drawn from the Swift/BAT AGN Spectroscopic Survey (BASS). This includes 30 AGN for which black hole mass (and therefore L/L_Edd) is measured directly through masers, spatially resolved gas or stellar dynamics, or reverberation mapping. The high quality and broad energy coverage of the data provided through BASS allow us to examine several alternative determinations of both Gamma_X and L/L_Edd. Read More

The relativistic jets created by some active galactic nuclei are important agents of AGN feedback. In spite of this, our understanding of what produces these jets is still incomplete. X-ray observations, which can probe the processes operating in the central regions in immediate vicinity of the supermassive black hole, the presumed jet launching point, are potentially particularly valuable in illuminating the jet formation process. Read More

We present results from a NuSTAR observation of the Crab made at a large off-axis angle of 1.5\degree. At these angles X-rays do not pass through the optics, but rather illuminate the detectors directly due to incomplete baffling. Read More

Active galactic nucleus (AGN) feedback is the process by which supermassive black holes in the centres of galaxies may moderate the growth of their hosts. Gas outflows from supermassive black holes release huge quantities of energy into the interstellar medium, clearing the surrounding gas. The most extreme of these, the ultra-fast outflows (UFOs), are the subset of X-ray detected outflows with velocities higher than 10,000 km/s, believed to originate in relativistic disc winds, a few hundred gravitational radii from the black hole. Read More

We present a spectral analysis of the NuSTAR and XMM-Newton observations of the Seyfert 1h galaxy/ULIRG IRAS 05189-2524 taken in 2013. We find evidence for relativistic disk reflection in the broadband X-ray spectrum: a highly asymmetric broad Fe K$\alpha$ emission line extending down to 3 keV and a Compton scattering component above 10 keV. Physical modeling with a self-consistent disk reflection model suggests the accretion disk is viewed at an intermediate angle with a super-solar iron abundance, and a mild constraint can be put on the high-energy cutoff of the power-law continuum. Read More

We present observations of the occulted active region AR12222 during the third {\em NuSTAR} solar campaign on 2014 December 11, with concurrent {\em SDO/}AIA and {\em FOXSI-2} sounding rocket observations. The active region produced a medium size solar flare one day before the observations, at $\sim18$UT on 2014 December 10, with the post-flare loops still visible at the time of {\em NuSTAR} observations. The time evolution of the source emission in the {\em SDO/}AIA $335\textrm{\AA}$ channel reveals the characteristics of an extreme-ultraviolet late phase event, caused by the continuous formation of new post-flare loops that arch higher and higher in the solar corona. Read More

We investigate the observed relationship between black hole mass ($M_{\rm BH}$), bolometric luminosity ($L_{\rm bol}$), and Eddington ratio (${\lambda}_{\rm Edd}$) with optical emission line ratios ([NII] {\lambda}6583/H{\alpha}, [SII] {\lambda}{\lambda}6716,6731/H{\alpha}, [OI] {\lambda}6300/H{\alpha}, [OIII] {\lambda}5007/H{\beta}, [NeIII] {\lambda}3869/H{\beta}, and HeII {\lambda}4686/H{\beta}) of hard X-ray-selected AGN from the BAT AGN Spectroscopic Survey (BASS). We show that the [NII] {\lambda}6583/H{\alpha} ratio exhibits a significant correlation with ${\lambda}_{\rm Edd}$ ($R_{\rm Pear}$ = -0.44, $p$-value=$3\times10^{-13}$, {\sigma} = 0. Read More

$Context:$ Intermediate-Mass Black Holes (IMBHs) are thought to be the seeds of early Supermassive Black Holes (SMBHs). While $\gtrsim$100 IMBH and small SMBH candidates have been identified in recent years, few have been robustly confirmed to date, leaving their number density in considerable doubt. Placing firmer constraints both on the methods used to identify and confirm IMBHs/SMBHs, as well as characterizing the range of host environments that IMBHs/SMBHs likely inhabit is therefore of considerable interest and importance. Read More

The Nuclear Spectroscopic Telescope Array (NuSTAR) is the first focusing high energy (3-79 keV) X-ray observatory operating for four years from low Earth orbit. The X-ray detector arrays are located on the spacecraft bus with the optics modules mounted on a flexible mast of 10.14m length. Read More

M82 X-1 is one of the brightest ultraluminous X-ray sources (ULXs) known, which, assuming Eddington-limited accretion and other considerations, makes it one of the best intermediate-mass black hole (IMBH) candidates. However, the ULX may still be explained by super-Eddington accretion onto a stellar-remnant black hole. We present simultaneous NuSTAR, Chandra and Swift/XRT observations during the peak of a flaring episode with the aim of modeling the emission of M82 X-1 and yielding insights into its nature. Read More

We obtained Keck/OSIRIS near-IR adaptive optics-assisted integral-field spectroscopy to probe the morphology and kinematics of the ionized gas in four velocity-offset active galactic nuclei (AGNs) from the Sloan Digital Sky Survey. These objects possess optical emission lines that are offset in velocity from systemic as measured from stellar absorption features. At a resolution of ~0. Read More

We study the geometry of the AGN obscurer in IRAS 09104+4109, an IR-luminous, radio-intermediate FR-I source at $z=0.442$, using infrared data from Spitzer and Herschel, X-ray data from Nustar, Swift, Suzaku, and Chandra, and an optical spectrum from Palomar. The infrared data imply a total rest-frame 1-1000$\mu$m luminosity of $5. Read More

We present results from the the first campaign of dedicated solar observations undertaken by the \textit{Nuclear Spectroscopic Telescope ARray} ({\em NuSTAR}) hard X-ray telescope. Designed as an astrophysics mission, {\em NuSTAR} nonetheless has the capability of directly imaging the Sun at hard X-ray energies ($>$3~keV) with an increase in sensitivity of at least two magnitude compared to current non-focusing telescopes. In this paper we describe the scientific areas where \textit{NuSTAR} will make major improvements on existing solar measurements. Read More

Recently, unresolved hard (20-40 keV) X-ray emission has been discovered within the central 10 pc of the Galaxy, possibly indicating a large population of intermediate polars (IPs). Chandra and XMM-Newton measurements in the surrounding ~50 pc imply a much lighter population of IPs with $\langle M_{\rm WD} \rangle \approx 0.5 M_\odot$. Read More

We report on a simultaneous NuSTAR and Swift observation of the neutron star low-mass X-ray binary 4U 1728-34. We identified and removed four Type I X-ray bursts during the observation in order to study the persistent emission. The continuum spectrum is hard and well described by a black body with $kT=$ 1. Read More

Affiliations: 1Georgia College, 2SSL-UC Berkeley, 3SSL-UC Berkeley, 4IKI Moscow, 5JPL-Caltech, 6Columbia University, 7ESO, 8SSL-UC Berkeley, 9DTU Space, 10SSL-UC Berkeley, 11Columbia University, 12Caltech, 13NASA-GSFC

The high-mass X-ray binary and accreting X-ray pulsar IGR J16393-4643 was observed by NuSTAR in the 3-79 keV energy band for a net exposure time of 50 ks. We present the results of this observation which enabled the discovery of a cyclotron resonant scattering feature with a centroid energy of 29.3(+1. Read More

We report on the results of NuSTAR and XMM-Newton observations of the persistent X-ray source 1E1743.1-2843, located in the Galactic Center region. The source was observed between September and October 2012 by NuSTAR and XMM-Newton, providing almost simultaneous observations in the hard and soft X-ray bands. Read More


We present the results of a joint Swift-NuSTAR spectroscopy campaign on M31. We focus on the five brightest globular cluster X-ray sources in our fields. Two of these had previously been argued to be black hole candidates on the basis of apparent hard-state spectra at luminosities above those for which neutron stars are in hard states. Read More

We present NuSTAR and Swift observations of the neutron star Aquila X-1 during the peak of its July 2014 outburst. The spectrum is soft with strong evidence for a broad Fe K\alpha line. Modeled with a relativistically broadened reflection model, we find that the inner disk is truncated with an inner radius of 15+/-3 R_G. Read More

We present a multi-epoch X-ray spectral analysis of the Seyfert 1 galaxy Fairall 9. Our analysis shows that Fairall 9 displays unique spectral variability in that its ratio residuals to a simple absorbed power law in the 0.5-10 keV band remain constant with time in spite of large variations in flux. Read More

Some reddened quasars appear to be transitional objects in the merger-induced black hole growth/galaxy evolution paradigm, where a heavily obscured nucleus starts to be unveiled by powerful quasar winds evacuating the surrounding cocoon of dust and gas. Hard X-ray observations are able to peer through this gas and dust, revealing the properties of circumnuclear obscuration. Here, we present NuSTAR and XMM-Newton/Chandra observations of FIRST-2MASS selected red quasars F2M 0830+3759 and F2M 1227+3214. Read More

ULX-7, in the northern spiral arm of M51, demonstrates unusual behaviour for an ultraluminous X-ray source, with a hard X-ray spectrum but very high short-term variability. This suggests that it is not in a typical ultraluminous state. We analyse the source using archival data from XMM-Newton, Chandra and NuSTAR, and by examining optical and radio data from HST and VLA. Read More

We present a hard X-ray NuSTAR observation of PSR J0437-4715, the nearest millisecond pulsar. The known pulsations at the apparent pulse period ~5.76 ms are detected at energies up to 20 keV. Read More

Affiliations: 1Washington University in Saint Louis, Physics Department and McDonnell Center for the Space Sciences, 2Jet Propulsion Laboratory, 3California Institute of Technology, Cahill Center for Astronomy and Astrophysics, 4Washington University in Saint Louis, Physics Department and McDonnell Center for the Space Sciences, 5Washington University in Saint Louis, Physics Department and McDonnell Center for the Space Sciences, 6Washington University in Saint Louis, Physics Department and McDonnell Center for the Space Sciences, 7Washington University in Saint Louis, Physics Department and McDonnell Center for the Space Sciences, 8Washington University in Saint Louis, Physics Department and McDonnell Center for the Space Sciences, 9Washington University in Saint Louis, Physics Department and McDonnell Center for the Space Sciences, 10Anton Pannekoek Institute for Astronomy, 11California Institute of Technology, Cahill Center for Astronomy and Astrophysics, 12California Institute of Technology, Cahill Center for Astronomy and Astrophysics, 13Jet Propulsion Laboratory, 14Jet Propulsion Laboratory, 15Rice University, Department of Physics and Astronomy, 16Washington University in Saint Louis, Physics Department and McDonnell Center for the Space Sciences, 17Georgia College, Department of Chemistry, Physics, and Astronomy, 18Jet Propulsion Laboratory, 19Jet Propulsion Laboratory, 20North-West University, Centre for Space Research, 21Technical University of Denmark, DTU Space, National Space Institute, 22Yale University, Department of Astronomy, 23Washington University in Saint Louis, Physics Department and McDonnell Center for the Space Sciences, 24University of Virginia, Department of Astronomy, 25MPI for Extraterrestrial Physics Garching, 26Durham University, Centre for Extragalactic Astronomy, Department of Physics, 27Jet Propulsion Laboratory, 28North Carolina State University, Department of Physics, 29Jet Propulsion Laboratory, 30Cambridge, Institute of Astronomy, UK, 31Penn State University, Department of Astronomy and Astrophysics, 32Jet Propulsion Laboratory, 33University of California, Berkeley, Department of Physics, 34ASI Science Data Center, Italy, 35California Institute of Technology, Cahill Center for Astronomy and Astrophysics, 36Cambridge, Institute of Astronomy, UK, 37Jet Propulsion Laboratory, 38Purdue University, Department of Physics and Astronomy, 39Texas Tech University, Physics Department, 40Nagoya University, Center for Experimental Studies, Kobayashi-Maskawa Institute for the Origin of Particles and the Universe, 41University of Maryland, Physics Department, 42RIKEN, 43Univ. of Michigan in Ann Arbor, Astronomy Dept, 44Harvard-Smithsonian Center for Astrophysics, 45Istituto di Astrofisica e Planetologia Spaziali, INAF, 46Department of Astronomy/Steward Observatory, 47Lawrence Livermore National Laboratory, 48Jet Propulsion Laboratory, 49Department of Astronomy/Steward Observatory, 50NASA Goddard Space Flight Center, 51Tohoku University, Astronomical Institute, 52NASA Goddard Space Flight Center

This paper describes the Polarization Spectroscopic Telescope Array (PolSTAR), a mission proposed to NASA's 2014 Small Explorer (SMEX) announcement of opportunity. PolSTAR measures the linear polarization of 3-50 keV (requirement; goal: 2.5-70 keV) X-rays probing the behavior of matter, radiation and the very fabric of spacetime under the extreme conditions close to the event horizons of black holes, as well as in and around magnetars and neutron stars. Read More

We present a NuSTAR, Chandra, and XMM--Newton survey of nine of the nearest ultraluminous infrared galaxies (ULIRGs). The unprecedented sensitivity of NuSTAR at energies above 10 keV enables spectral modeling with far better precision than was previously possible. Six of the nine sources observed were detected sufficiently well by NuSTAR to model in detail their broadband X-ray spectra, and recover the levels of obscuration and intrinsic X-ray luminosities. Read More

We present the results from a joint Suzaku/NuSTAR broad-band spectral analysis of 3C 390.3. The high quality data enables us to clearly separate the primary continuum from the reprocessed components allowing us to detect a high energy spectral cut-off ($E_\text{cut}=117_{-14}^{+18}$ keV), and to place constraints on the Comptonization parameters of the primary continuum for the first time. Read More

We investigate the relationship between X-ray and optical line emission in 340 nearby AGN selected above 10 keV using Swift BAT. We find a weak correlation between the extinction corrected [O III] and hard X-ray luminosity (14-195 keV) with a [OIII] large scatter (R_Pear = 0.64, sigma = 0. Read More

We report on Nuclear Spectroscopic Telescope Array (NuSTAR) hard X-ray observations of the young rotation-powered radio pulsar PSR B1509$-$58 in the supernova remnant MSH 15$-$52. We confirm the previously reported curvature in the hard X-ray spectrum, showing that a log parabolic model provides a statistically superior fit to the spectrum compared with the standard power law. The log parabolic model describes the NuSTAR data, as well as previously published gamma-ray data obtained with COMPTEL and AGILE, all together spanning 3 keV through 500 MeV. Read More

Galactic Center (GC) molecular cloud Sgr B2 is the best manifestation of an X-ray reflection nebula (XRN) reprocessing a past giant outburst from the supermassive black hole Sgr A*. Alternatively, Sgr B2 could be illuminated by low-energy cosmic ray electrons (LECRe) or protons (LECRp). In 2013, NuSTAR for the first time resolved Sgr B2 hard X-ray emission on sub-arcminute scales. Read More

The recent discovery by Bachetti et al. (2014) of a pulsar in M82 that can reach luminosities of up to 10^40 ergs s^-1, a factor of ~100 the Eddington luminosity for a 1.4 Msol compact object, poses a challenge for accretion physics. Read More

Affiliations: 1SSL-UC Berkeley, CA, USA, 2Tuorla Observatory, Department of Physics and Astronomy, University of Turku, Finland, 3Space Research Institute, 4SSL-UC Berkeley, CA, USA, 5MIT Kavli Institute for Astrophysics and Space Research, Cambridge, MA, USA, 6Observatoire Midi-Pyrenees, Universite de Toulouse, France, 7SSL-UC Berkeley, CA, USA, 8Dublin City University, Ireland, 9DTU Space - National Space Institute, Technical University of Denmark, Denmark, 10Lawrence Livermore National Laboratory, Livermore, CA, USA, 11Cahill Center for Astronomy and Astrophysics, California Institute of Technology, Pasadena, CA, USA, 12Columbia Astrophysics Laboratory, Columbia University, New York, USA, 13Cahill Center for Astronomy and Astrophysics, California Institute of Technology, Pasadena, CA, USA, 14Department of Physics, University of Durham, UK, 15European Southern Observatory, Garching bei Muenchen, Germany, 16Jet Propulsion Laboratory, California Institute of Technology, Pasadena, CA, USA, 17NASA Goddard Space Flight Center, Greenbelt, MD, USA

We present spectral and timing analysis of NuSTAR observations of the accreting X-ray pulsar 2RXP J130159.6-635806. The source was serendipitously observed during a campaign focused on the gamma-ray binary PSR B1259-63 and was later targeted for a dedicated observation. Read More

We present results from multi-wavelength simultaneous X-ray and radio observations of the black hole X-ray binary V404 Cyg in quiescence. Our coverage with NuSTAR provides the very first opportunity to study the X-ray spectrum of V404 Cyg at energies above 10 keV. The unabsorbed broad-band (0. Read More

We present NuSTAR observations of the powerful radio galaxy Cygnus A, focusing on the central absorbed active galactic nucleus (AGN). Cygnus A is embedded in a cool-core galaxy cluster, and hence we also examine archival XMM-Newton data to facilitate the decomposition of the spectrum into the AGN and intracluster medium (ICM) components. NuSTAR gives a source-dominated spectrum of the AGN out to >70keV. Read More

Affiliations: 1SSL/UCB, 2ESO and Harvard, 3Oxford, 4Curtin University, 5Caltech, 6Nagoya University, 7Hiroshima University, 8AIM and Observatoire de Paris, 9IRAP, 10University of Durham, 11University of Southampton, 12Caltech, 13Taiwan Normal University, 14University of Iowa, 15Sabanci University, 16Hiroshima University, 17ESAC, 18University of Michigan, 19Nagoya University and University of Tokyo, 20JPL, 21Nagoya University, 22National Central Univeristy

(abridged) We report on multi-wavelength measurements of Swift J1753.5-0127 in the hard state at L=2.7e36 erg/s (assuming d=3 kpc) in 2014. Read More

We present results from a 244\,ks \textit{NuSTAR} observation of 3C\,273 obtained during a cross-calibration campaign with the \textit{Chandra}, \textit{INTEGRAL}, \textit{Suzaku}, \textit{Swift}, and \textit{XMM-Newton} observatories. We show that the spectrum, when fit with a power-law model using data from all observatories except \textit{INTEGRAL} over the 1--78\,keV band, leaves significant residuals in the \textit{NuSTAR} data between 30--78\,keV. The \nustar\ 3--78\,keV spectrum is well-described by an exponentially cutoff power-law ($\Gamma = 1. Read More

Affiliations: 1CalTech, 2Columbia University, 3Beijing Institute of Technology, 4McGill University, 5Columbia University, 6KIPAC, Stanford, 7INAF Cagliari, 8SSL, UC Berkeley, 9DTU Space, 10DTU Space, 11McGill University, 12Columbia University, 13CalTech, 14NASA JPL, 15NASA GSFC

We present temporal and spectral analysis of simultaneous 0.5-79 keV Swift-XRT and NuSTAR observations of the magnetar 4U 0142+61. The pulse profile changes significantly with photon energy between 3 and 35 keV. Read More

The black hole candidate XTE J1908+094 went into outburst for the first time since 2003 in October 2013. We report on an observation with the Nuclear Spectroscopic Telescope Array (NuSTAR) and monitoring observations with Swift during the outburst. NuSTAR caught the source in the soft state: the spectra show a broad relativistic iron line, and the light curves reveal a ~40 ks flare with the count rate peaking about 40% above the non-flare level and with significant spectral variation. Read More

We report on a 350-ks NuSTAR observation of the magnetar 1E 1841-045 taken in 2013 September. During the observation, NuSTAR detected six bursts of short duration, with $T_{90}<1$ s. An elevated level of emission tail is detected after the brightest burst, persisting for $\sim$1 ks. Read More

Authors: Warren Skidmore, Ian Dell'Antonio, Misato Fukugawa, Aruna Goswami, Lei Hao, David Jewitt, Greg Laughlin, Charles Steidel, Paul Hickson, Luc Simard, Matthias Schöck, Tommaso Treu, Judith Cohen, G. C. Anupama, Mark Dickinson, Fiona Harrison, Tadayuki Kodama, Jessica R. Lu, Bruce Macintosh, Matt Malkan, Shude Mao, Norio Narita, Tomohiko Sekiguchi, Annapurni Subramaniam, Masaomi Tanaka, Feng Tian, Michael A'Hearn, Masayuki Akiyama, Babar Ali, Wako Aoki, Manjari Bagchi, Aaron Barth, Varun Bhalerao, Marusa Bradac, James Bullock, Adam J. Burgasser, Scott Chapman, Ranga-Ram Chary, Masashi Chiba, Michael Cooper, Asantha Cooray, Ian Crossfield, Thayne Currie, Mousumi Das, G. C. Dewangan, Richard de Grijs, Tuan Do, Subo Dong, Jarah Evslin, Taotao Fang, Xuan Fang, Christopher Fassnacht, Leigh Fletcher, Eric Gaidos, Roy Gal, Andrea Ghez, Mauro Giavalisco, Carol A. Grady, Thomas Greathouse, Rupjyoti Gogoi, Puragra Guhathakurta, Luis Ho, Priya Hasan, Gregory J. Herczeg, Mitsuhiko Honda, Masa Imanishi, Hanae Inami, Masanori Iye, Jason Kalirai, U. S. Kamath, Stephen Kane, Nobunari Kashikawa, Mansi Kasliwal, Vishal Kasliwal, Evan Kirby, Quinn M. Konopacky, Sebastien Lepine, Di Li, Jianyang Li, Junjun Liu, Michael C. Liu, Enrigue Lopez-Rodriguez, Jennifer Lotz, Philip Lubin, Lucas Macri, Keiichi Maeda, Franck Marchis, Christian Marois, Alan Marscher, Crystal Martin, Taro Matsuo, Claire Max, Alan McConnachie, Stacy McGough, Carl Melis, Leo Meyer, Michael Mumma, Takayuki Muto, Tohru Nagao, Joan R. Najita, Julio Navarro, Michael Pierce, Jason X. Prochaska, Masamune Oguri, Devendra K. Ojha, Yoshiko K. Okamoto, Glenn Orton, Angel Otarola, Masami Ouchi, Chris Packham, Deborah L. Padgett, Shashi Bhushan Pandey, Catherine Pilachowsky, Klaus M. Pontoppidan, Joel Primack, Shalima Puthiyaveettil, Enrico Ramirez-Ruiz, Naveen Reddy, Michael Rich, Matthew J. Richter, James Schombert, Anjan Ananda Sen, Jianrong Shi, Kartik Sheth, R. Srianand, Jonathan C. Tan, Masayuki Tanaka, Angelle Tanner, Nozomu Tominaga, David Tytler, Vivian U, Lingzhi Wang, Xiaofeng Wang, Yiping Wang, Gillian Wilson, Shelley Wright, Chao Wu, Xufeng Wu, Renxin Xu, Toru Yamada, Bin Yang, Gongbo Zhao, Hongsheng Zhao

The TMT Detailed Science Case describes the transformational science that the Thirty Meter Telescope will enable. Planned to begin science operations in 2024, TMT will open up opportunities for revolutionary discoveries in essentially every field of astronomy, astrophysics and cosmology, seeing much fainter objects much more clearly than existing telescopes. Per this capability, TMT's science agenda fills all of space and time, from nearby comets and asteroids, to exoplanets, to the most distant galaxies, and all the way back to the very first sources of light in the Universe. Read More

We report results from deep observations (~750 ks) of Tycho's supernova remnant (SNR) with NuSTAR. Using these data, we produce narrow-band images over several energy bands to identify the regions producing the hardest X-rays and to search for radioactive decay line emission from 44Ti. We find that the hardest (>10 keV) X-rays are concentrated in the southwest of Tycho, where recent Chandra observations have revealed high emissivity "stripes" associated with particles accelerated to the knee of the cosmic-ray spectrum. Read More

We present the calibration of the \textit{Nuclear Spectroscopic Telescope Array} (\nustar) X-ray satellite. We used the Crab as the primary effective area calibrator and constructed a piece-wise linear spline function to modify the vignetting response. The achieved residuals for all off-axis angles and energies, compared to the assumed spectrum, are typically better than $\pm 2$\% up to 40\,keV and 5--10\,\% above due to limited counting statistics. Read More

We present broadband (3 -- 78 keV) NuSTAR X-ray imaging and spectroscopy of the Crab nebula and pulsar. We show that while the phase-averaged and spatially integrated nebula + pulsar spectrum is a power-law in this energy band, spatially resolved spectroscopy of the nebula finds a break at $\sim$9 keV in the spectral photon index of the torus structure with a steepening characterized by $\Delta\Gamma\sim0.25$. Read More