Author
Nicholas E. White
Other affiliations: George Washington University, European Space Research and Technology Centre
Bio: Nicholas E. White is an academic researcher from Goddard Space Flight Center. The author has contributed to research in topics: Luminosity & Neutron star. The author has an hindex of 48, co-authored 192 publications receiving 13977 citations. Previous affiliations of Nicholas E. White include George Washington University & European Space Research and Technology Centre.
Topics: Luminosity, Neutron star, Pulsar, Galaxy, Binary star
Papers published on a yearly basis
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Goddard Space Flight Center1, University of Milan2, Brera Astronomical Observatory3, University College London4, Pennsylvania State University5, University of Leicester6, Sonoma State University7, University of California, Berkeley8, Universities Space Research Association9, National Research Council10, University of Southampton11, Los Alamos National Laboratory12, National Radio Astronomy Observatory13, Space Telescope Science Institute14, Max Planck Society15, California Institute of Technology16, University of Texas at Austin17, French Alternative Energies and Atomic Energy Commission18, University of Toronto19, University of Maryland, College Park20, Princeton University21, Lawrence Livermore National Laboratory22, University of Cambridge23, University of California, Santa Barbara24, Rice University25, University of Tokyo26, Saitama University27, University of Florence28
TL;DR: The Swift mission as discussed by the authors is a multi-wavelength observatory for gamma-ray burst (GRB) astronomy, which is a first-of-its-kind autonomous rapid-slewing satellite for transient astronomy and pioneers the way for future rapid-reaction and multiwavelength missions.
Abstract: The Swift mission, scheduled for launch in 2004, is a multiwavelength observatory for gamma-ray burst (GRB) astronomy. It is a first-of-its-kind autonomous rapid-slewing satellite for transient astronomy and pioneers the way for future rapid-reaction and multiwavelength missions. It will be far more powerful than any previous GRB mission, observing more than 100 bursts yr � 1 and performing detailed X-ray and UV/optical afterglow observations spanning timescales from 1 minute to several days after the burst. The objectives are to (1) determine the origin of GRBs, (2) classify GRBs and search for new types, (3) study the interaction of the ultrarelativistic outflows of GRBs with their surrounding medium, and (4) use GRBs to study the early universe out to z >10. The mission is being developed by a NASA-led international collaboration. It will carry three instruments: a newgeneration wide-field gamma-ray (15‐150 keV) detector that will detect bursts, calculate 1 0 ‐4 0 positions, and trigger autonomous spacecraft slews; a narrow-field X-ray telescope that will give 5 00 positions and perform spectroscopy in the 0.2‐10 keV band; and a narrow-field UV/optical telescope that will operate in the 170‐ 600 nm band and provide 0B3 positions and optical finding charts. Redshift determinations will be made for most bursts. In addition to the primary GRB science, the mission will perform a hard X-ray survey to a sensitivity of � 1m crab (� 2;10 � 11 ergs cm � 2 s � 1 in the 15‐150 keV band), more than an order of magnitude better than HEAO 1 A-4. A flexible data and operations system will allow rapid follow-up observations of all types of
3,753 citations
TL;DR: Les spectres RX de nombreuses sources de trous noirs en accretion suggerent la presence de matiere relativement froide entouree d'un plasma emetteur de RX dur.
Abstract: Les spectres RX de nombreuses sources de trous noirs en accretion suggerent la presence de matiere relativement froide entouree d'un plasma emetteur de RX dur. Les raies fluorescentes du fer sont produites par l'irradiation RX du gaz froid. On montre que la raie d'emission large du fer trouvee dans Cyg X-1 par Barr P., White N.E. et Page C.G. (1985, Mon. Not. R. astr. Soc., 216) est bien modelisee par une emission fluorescente emanant des parties internes d'un disque d'accretion
1,431 citations
Massachusetts Institute of Technology1, Goddard Space Flight Center2, Kyoto University3, Nagoya University4, University of Tokyo5, Osaka University6, Ehime University7, University of Cambridge8, Hiroshima University9, Carnegie Mellon University10, Max Planck Society11, University of Miyazaki12, Franklin W. Olin College of Engineering13, Rutgers University14, Tokyo Metropolitan University15, Kobe University16, Stanford University17, Tokyo Institute of Technology18, Rikkyo University19, Kogakuin University20, Tokyo University of Science21, University of Wisconsin-Madison22, Kanazawa University23, Nihon University24, Pennsylvania State University25, European Space Research and Technology Centre26, Yale University27, Saitama University28, Chuo University29, University of Leicester30, Nihon Fukushi University31, Aoyama Gakuin University32, Iwate University33
TL;DR: In this paper, the authors summarized the spacecraft, in-orbit performance, operations, and data processing that are related to observations of the Suzaku X-ray observatory, including high-sensitivity wide-band Xray spectroscopy.
Abstract: High-sensitivity wide-band X-ray spectroscopy is the key feature of the Suzaku X-ray observatory, launched on 2005 July 10. This paper summarizes the spacecraft, in-orbit performance, operations, and data processing that are related to observations. The scientific instruments, the high-throughput X-ray telescopes, X-ray CCD cameras, non-imaging hard X-ray detector are also described.
908 citations
INAF1, Pennsylvania State University2, University of Milan3, National Research Council4, Goddard Space Flight Center5, Kavli Institute for Theoretical Physics6, International School for Advanced Studies7, Weizmann Institute of Science8, University of Nevada, Las Vegas9, Nanjing University10, Polaris Industries11, University of Leicester12, Sonoma State University13, Universities Space Research Association14, Los Alamos National Laboratory15
TL;DR: A supernova is caught in the act of exploding, directly observing the shock break-out, which indicates that the GRB progenitor was a Wolf–Rayet star.
Abstract: A link between long γ-ray bursts (GRBs) and supernovae has been established, but whether there is a similar relationship between the weaker and softer X-ray flashes and supernovae is unclear. GRB/XRF 060218, spotted by the Swift satellite on 18 February this year, may supply that missing link. In the first of four papers on this novel burster, Campana et al. report the sighting of the X-ray signature of a shock break-out, possible evidence of a supernova in progress. Pian et al. report the optical discovery of a type Ic supernova 2006aj associated with GRB/XRF 060218. Soderberg et al. report radio and X-ray observations that show that XRF 060218 is 100 times less energetic than, but of a type that is ten times more common than cosmological GRBs. Mazzali et al. modelled the spectra and light curve of SN 2006aj to show that it had a much smaller explosion energy and ejected much less mass than other GRB-supernovae, suggesting that it was produced by a star with a mass was only about 20 times that of the Sun, leaving behind a neutron star, rather than a black hole. Observations of the close gamma-ray burst GRB 060218 and its connection to supernova SN 2006aj reveal the break-out of a shock wave driven by a mildly relativistic shell into the dense wind surrounding the GRB progenitor. These observation catch a supernova in the act of exploding. Although the link between long γ-ray bursts (GRBs) and supernovae has been established1,2,3,4, hitherto there have been no observations of the beginning of a supernova explosion and its intimate link to a GRB. In particular, we do not know how the jet that defines a γ-ray burst emerges from the star's surface, nor how a GRB progenitor explodes. Here we report observations of the relatively nearby GRB 060218 (ref. 5) and its connection to supernova SN 2006aj (ref. 6). In addition to the classical non-thermal emission, GRB 060218 shows a thermal component in its X-ray spectrum, which cools and shifts into the optical/ultraviolet band as time passes. We interpret these features as arising from the break-out of a shock wave driven by a mildly relativistic shell into the dense wind surrounding the progenitor7. We have caught a supernova in the act of exploding, directly observing the shock break-out, which indicates that the GRB progenitor was a Wolf–Rayet star.
835 citations
Goddard Space Flight Center1, University of Virginia2, University of Leicester3, University of Nevada, Las Vegas4, University College London5, Pennsylvania State University6, University of Maryland, Baltimore County7, National Research Council8, Universities Space Research Association9, University of Maryland, College Park10, Los Alamos National Laboratory11, Brera Astronomical Observatory12, University of Milan13, INAF14, Sonoma State University15, University of Copenhagen16, University of California, Berkeley17, Marshall Space Flight Center18, Stockholm University19, University of Amsterdam20, Saitama University21
TL;DR: In this article, the authors reported the detection of the X-ray afterglow from the short burst GRB 050509B and its location on the sky is near a luminous, non-star-forming elliptical galaxy at a redshift of 0.225.
Abstract: Gamma-ray bursts (GRBs) are either ‘long and soft’, or ‘short and hard’. The long-duration type leave a strong afterglow and have been extensively studied. So we have a good idea of what causes them: explosions of massive stars in distant star-forming galaxies. Short GRBs, with no strong afterglow, were harder to pin down. The Swift satellite, launched last November, is designed to study bursts as soon as they happen. Having shown its worth with long GRBs (reported in the 18 August issue of Nature), Swift has now bagged a short burst, GRB 050509B, precisely measured its location and detected the X-ray afterglow. Four papers this week report on this and another recent short burst. Now, over 20 years after they were first recognized, the likely origin of the short GRBs is revealed as a merger between neutron stars of a binary system and the instantaneous production of a black hole. Gamma-ray bursts (GRBs) come in two classes1: long (> 2 s), soft-spectrum bursts and short, hard events. Most progress has been made on understanding the long GRBs, which are typically observed at high redshift (z ≈ 1) and found in subluminous star-forming host galaxies. They are likely to be produced in core-collapse explosions of massive stars2. In contrast, no short GRB had been accurately (< 10″) and rapidly (minutes) located. Here we report the detection of the X-ray afterglow from—and the localization of—the short burst GRB 050509B. Its position on the sky is near a luminous, non-star-forming elliptical galaxy at a redshift of 0.225, which is the location one would expect3,4 if the origin of this GRB is through the merger of neutron-star or black-hole binaries. The X-ray afterglow was weak and faded below the detection limit within a few hours; no optical afterglow was detected to stringent limits, explaining the past difficulty in localizing short GRBs.
590 citations
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Goddard Space Flight Center1, University of Milan2, Brera Astronomical Observatory3, University College London4, Pennsylvania State University5, University of Leicester6, Sonoma State University7, University of California, Berkeley8, Universities Space Research Association9, National Research Council10, University of Southampton11, Los Alamos National Laboratory12, National Radio Astronomy Observatory13, Space Telescope Science Institute14, Max Planck Society15, California Institute of Technology16, University of Texas at Austin17, French Alternative Energies and Atomic Energy Commission18, University of Toronto19, University of Maryland, College Park20, Princeton University21, Lawrence Livermore National Laboratory22, University of Cambridge23, University of California, Santa Barbara24, Rice University25, University of Tokyo26, Saitama University27, University of Florence28
TL;DR: The Swift mission as discussed by the authors is a multi-wavelength observatory for gamma-ray burst (GRB) astronomy, which is a first-of-its-kind autonomous rapid-slewing satellite for transient astronomy and pioneers the way for future rapid-reaction and multiwavelength missions.
Abstract: The Swift mission, scheduled for launch in 2004, is a multiwavelength observatory for gamma-ray burst (GRB) astronomy. It is a first-of-its-kind autonomous rapid-slewing satellite for transient astronomy and pioneers the way for future rapid-reaction and multiwavelength missions. It will be far more powerful than any previous GRB mission, observing more than 100 bursts yr � 1 and performing detailed X-ray and UV/optical afterglow observations spanning timescales from 1 minute to several days after the burst. The objectives are to (1) determine the origin of GRBs, (2) classify GRBs and search for new types, (3) study the interaction of the ultrarelativistic outflows of GRBs with their surrounding medium, and (4) use GRBs to study the early universe out to z >10. The mission is being developed by a NASA-led international collaboration. It will carry three instruments: a newgeneration wide-field gamma-ray (15‐150 keV) detector that will detect bursts, calculate 1 0 ‐4 0 positions, and trigger autonomous spacecraft slews; a narrow-field X-ray telescope that will give 5 00 positions and perform spectroscopy in the 0.2‐10 keV band; and a narrow-field UV/optical telescope that will operate in the 170‐ 600 nm band and provide 0B3 positions and optical finding charts. Redshift determinations will be made for most bursts. In addition to the primary GRB science, the mission will perform a hard X-ray survey to a sensitivity of � 1m crab (� 2;10 � 11 ergs cm � 2 s � 1 in the 15‐150 keV band), more than an order of magnitude better than HEAO 1 A-4. A flexible data and operations system will allow rapid follow-up observations of all types of
3,753 citations
TL;DR: In this paper, an improved model for the absorption of X-rays in the interstellar medium (ISM) is presented for use with data from future X-ray missions with larger effective areas and increased energy resolution such as Chandra and the X-Ray Multiple Mirror mission.
Abstract: We present an improved model for the absorption of X-rays in the interstellar medium (ISM) intended for use with data from future X-ray missions with larger effective areas and increased energy resolution such as Chandra and the X-Ray Multiple Mirror mission, in the energy range 100 eV. Compared with previous work, our formalism includes recent updates to the photoionization cross section and revised abundances of the interstellar medium, as well as a treatment of interstellar grains and the H2 molecule. We review the theoretical and observational motivations behind these updates and provide a subroutine for the X-ray spectral analysis program XSPEC that incorporates our model.
3,239 citations
University of Geneva1, Ioffe Institute2, University of California, Santa Cruz3, University of Mississippi4, Curtin University5, University of California, Santa Barbara6, Las Cumbres Observatory Global Telescope Network7, University of Warwick8, Spanish National Research Council9, University of Colorado Boulder10, University of Hawaii11, Aoyama Gakuin University12, Queen's University Belfast13, Max Planck Society14, Nagoya University15, University of Warsaw16
TL;DR: A binary neutron star coalescence candidate (later designated GW170817) with merger time 12:41:04 UTC was observed through gravitational waves by the Advanced LIGO and Advanced Virgo detectors.
Abstract: On 2017 August 17 a binary neutron star coalescence candidate (later designated GW170817) with merger time 12:41:04 UTC was observed through gravitational waves by the Advanced LIGO and Advanced Virgo detectors. The Fermi Gamma-ray Burst Monitor independently detected a gamma-ray burst (GRB 170817A) with a time delay of $\sim 1.7\,{\rm{s}}$ with respect to the merger time. From the gravitational-wave signal, the source was initially localized to a sky region of 31 deg2 at a luminosity distance of ${40}_{-8}^{+8}$ Mpc and with component masses consistent with neutron stars. The component masses were later measured to be in the range 0.86 to 2.26 $\,{M}_{\odot }$. An extensive observing campaign was launched across the electromagnetic spectrum leading to the discovery of a bright optical transient (SSS17a, now with the IAU identification of AT 2017gfo) in NGC 4993 (at $\sim 40\,{\rm{Mpc}}$) less than 11 hours after the merger by the One-Meter, Two Hemisphere (1M2H) team using the 1 m Swope Telescope. The optical transient was independently detected by multiple teams within an hour. Subsequent observations targeted the object and its environment. Early ultraviolet observations revealed a blue transient that faded within 48 hours. Optical and infrared observations showed a redward evolution over ~10 days. Following early non-detections, X-ray and radio emission were discovered at the transient's position $\sim 9$ and $\sim 16$ days, respectively, after the merger. Both the X-ray and radio emission likely arise from a physical process that is distinct from the one that generates the UV/optical/near-infrared emission. No ultra-high-energy gamma-rays and no neutrino candidates consistent with the source were found in follow-up searches. These observations support the hypothesis that GW170817 was produced by the merger of two neutron stars in NGC 4993 followed by a short gamma-ray burst (GRB 170817A) and a kilonova/macronova powered by the radioactive decay of r-process nuclei synthesized in the ejecta.
2,746 citations
TL;DR: In this paper, a summary of what is now known of disk turbulence and some knotty outstanding questions (e.g., what is the physics behind nonlinear field saturation?) for which we may soon begin to develop answers.
Abstract: Recent years have witnessed dramatic progress in our understanding of how turbulence arises and transports angular momentum in astrophysical accretion disks. The key conceptual point has its origins in work dating from the 1950s, but its implications have been fully understood only in the last several years: the combination of a subthermal magnetic field (any nonpathological configuration will do) and outwardly decreasing differential rotation rapidly generates magnetohydrodynamic (MHD) turbulence via a remarkably simple linear instability. The result is a greatly enhanced effective viscosity, the origin of which had been a long-standing problem. The MHD nature of disk turbulence has linked two broad domains of magnetized fluid research: accretion theory and dynamos. The understanding that weak magnetic fields are not merely passively acted upon by turbulence, but actively generate it, means that the assumptions of classical dynamo theory break down in disks. Paralleling the new conceptual understanding has been the development of powerful numerical MHD codes. These have taught us that disks truly are turbulent, transporting angular momentum at greatly enhanced rates. We have also learned, however, that not all forms of disk turbulence do this. Purely hydrodynamic turbulence, when it is imposed, simply causes fluctuations without a significant increase in transport. The interplay between numerical simulation and analytic arguments has been particularly fruitful in accretion disk theory and is a major focus of this article. The authors conclude with a summary of what is now known of disk turbulence and mention some knotty outstanding questions (e.g., what is the physics behind nonlinear field saturation?) for which we may soon begin to develop answers.
2,465 citations
TL;DR: In this article, it was shown that the radiative or quasar mode of feedback can account for the observed proportionality between the central black hole and the host galaxy mass, which can lead to ejection or heating of the gas.
Abstract: Radiation, winds, and jets from the active nucleus of a massive galaxy can interact with its interstellar medium, and this can lead to ejection or heating of the gas. This terminates star formation in the galaxy and stifles accretion onto the black hole. Such active galactic nuclei (AGN) feedback can account for the observed proportionality between the central black hole and the host galaxy mass. Direct observational evidence for the radiative or quasar mode of feedback, which occurs when AGN are very luminous, has been difficult to obtain but is accumulating from a few exceptional objects. Feedback from the kinetic or radio mode, which uses the mechanical energy of radio-emitting jets often seen when AGN are operating at a lower level, is common in massive elliptical galaxies. This mode is well observed directly through X-ray observations of the central galaxies of cool core clusters in the form of bubbles in the hot surrounding medium. The energy flow, which is roughly continuous, heats the hot intraclu...
2,299 citations