J. E. Grindlay
A5054070152- Astrophysical Phenomena and Observations
- Gamma-ray bursts and supernovae
- Astronomy and Astrophysical Research
- Stellar, planetary, and galactic studies
- Astronomical Observations and Instrumentation
- Pulsars and Gravitational Waves Research
- Particle Detector Development and Performance
- Astrophysics and Cosmic Phenomena
- High-pressure geophysics and materials
- Astrophysics and Star Formation Studies
- Nuclear Physics and Applications
- Advanced Semiconductor Detectors and Materials
- Astro and Planetary Science
- Advanced X-ray Imaging Techniques
- Particle Accelerators and Free-Electron Lasers
- Galaxies: Formation, Evolution, Phenomena
- Advanced X-ray and CT Imaging
- History and Developments in Astronomy
- Adaptive optics and wavefront sensing
- X-ray Spectroscopy and Fluorescence Analysis
- Mechanics and Biomechanics Studies
- Calibration and Measurement Techniques
- Radiation Detection and Scintillator Technologies
- Solar and Space Plasma Dynamics
- Geophysics and Gravity Measurements
Center for Astrophysics Harvard & Smithsonian
2015-2024
Harvard University
2011-2024
Harvard University Press
2002-2019
University of Arizona
2019
Harvard College Observatory
2001-2018
Max Planck Society
2015
Max Planck Institute for Radio Astronomy
2015
University of California, San Diego
2013
Institut de Recherche sur les Lois Fondamentales de l'Univers
2013
Commissariat à l'Énergie Atomique et aux Énergies Alternatives
2013
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 During its approach to asteroid (101955) Bennu, NASA’s Origins, Spectral Interpretation, Resource Identification, and Security-Regolith Explorer (OSIRIS-REx) spacecraft surveyed Bennu’s immediate environment, photometric properties, rotation state. Discovery of a dusty natural satellite, or unexpected characteristics would have had consequences for the mission’s safety observation strategy. Here we show that observations during this period were highly sensitive satellites (sub-meter...
view Abstract Citations (643) References (15) Co-Reads Similar Papers Volume Content Graphics Metrics Export Citation NASA/ADS On searches for pulsed emission with application to four globular cluster X-ray sources : NGC 1851, 6441, 6624 and 6712. Leahy, D. A. ; Darbro, W. Elsner, R. F. Weisskopf, M. C. Sutherland, P. G. Kahn, S. Grindlay, J. E. Periodic pulsations have been sought in the 6624, 6712 sources' emission, using Einstein Observatory's Monitor Proportional Counter. Special...
view Abstract Citations (834) References (17) Co-Reads Similar Papers Volume Content Graphics Metrics Export Citation NASA/ADS The Einstein (HEAO 2) X-ray Observatory. Giacconi, R. ; Branduardi, G. Briel, U. Epstein, A. Fabricant, D. Feigelson, E. Forman, W. Gorenstein, P. Grindlay, J. Gursky, H. Harnden, F. Henry, Jones, C. Kellogg, Koch, Murray, S. Schreier, Seward, Tananbaum, Topka, K. Van Speybroeck, L. Holt, Becker, Boldt, Serlemitsos, Clark, Canizares, Markert, T. Novick, Helfand,...
Sagittarius A*, which is located at the Galactic center, a puzzling source. It has mass of M = (2.5 ± 0.4) × 106 M☉, makes it an excellent black hole candidate. Observations stellar winds and other gas flows in its vicinity suggest accretion rate ≳ few 10−6 M☉ yr-1. However, such would imply luminosity greater than 1040 ergs-1 if radiative efficiency usual 10%, whereas observations indicate bolometric less 1037 ergs-1. The spectrum Sgr A* unusual, with emission extending over many decades...
Current X-ray missions are providing high-quality spectra from neutron stars (NSs) in quiescent low-mass binaries (qLMXBs). This has motivated us to calculate new hydrogen-atmosphere models, including opacity due free-free absorption and Thomson scattering, thermal electron conduction, self-irradiation by photons the compact object. We have constructed a self-consistent grid of star models covering wide range surface gravities as well effective temperatures, which we make available...
view Abstract Citations (287) References (14) Co-Reads Similar Papers Volume Content Graphics Metrics Export Citation NASA/ADS Discovery of intense X-ray bursts from the globular cluster NGC 6624. Grindlay, J. ; Gursky, H. Schnopper, Parsignault, D. R. Heise, Brinkman, A. C. Schrijver, A new type time variation cosmic sources has been found Astronomical Netherlands Satellite (ANS) observations source 3U 1820-30, associated with Two in 1-30 keV intensity this are reported. Each displayed a...
view Abstract Citations (332) References (68) Co-Reads Similar Papers Volume Content Graphics Metrics Export Citation NASA/ADS Einstein observations of the Rho Ophiuchi dark cloud : an X-ray christmas tree. Montmerle, T. ; Koch-Miramond, L. Falgarone, E. Grindlay, J. The results obtained by extensive Observatory investigation region, emphasizing findings pertaining to densest part cloud. and specific features data analysis are briefly described, space distribution sources in is discussed,...
view Abstract Citations (345) References (23) Co-Reads Similar Papers Volume Content Graphics Metrics Export Citation NASA/ADS The distribution and morphology of X-ray emitting gas in the core Perseus cluster. Fabian, A. C. ; Hu, E. M. Cowie, L. Grindlay, J. An unresolved source has been found coincident with nucleus NGC 1275 a high-resolution image Absorption optical features at high velocity respect to 1275, which are thought be associated foreground galaxy, does not produce any detectable...
We have obtained high-resolution (approximately 1") deep x-ray images of the globular cluster 47Tucanae (NGC 104) with Chandra X-ray Observatory to study population compact binaries in high stellar density core. A 70-kilosecond exposure reveals a centrally concentrated faint (Lx approximately 10(30-33) ergs per second) sources, at least 108 located within central 2' x 2.5' and greater, similar half Lx 10(30.5) second. All 15 millisecond pulsars (MSPs) recently precisely by radio observations...
view Abstract Citations (263) References (26) Co-Reads Similar Papers Volume Content Graphics Metrics Export Citation NASA/ADS Discovery of an X-ray star association in VI Cygni (Cyg OB2). Harnden, F. R., Jr. ; Branduardi, G. Elvis, M. Gorenstein, P. Grindlay, J. Pye, Rosner, R. Topka, K. Vaiana, S. A group six sources located within 0.4 deg Cygnus X-3 has been discovered with the Einstein Observatory. These have positively identified and five them correspond to stars heavily obscured OB...
Optical light curves and spectra of the Type Ia supernova 1986G in NGC 5128 (Centaurus A) are presented. Although spectral evolution closely resembled that more common "slower" photometric classes supernovae, subtle differences maximum-light were detected. The expansion velocity photosphere SN decreased rapidly at early phases. appears to have been heavily obscured by dust lane 5128. This circumstances accounts for strong interstellar-absorption lines Ca II H K Na I D observed as well...
We use Chandra and XMM observations of the globular clusters $\omega$ Cen NGC 6397 to measure spectrum their quiescent neutron stars (NSs), thus constrain allowed ranges mass radius for each. also Hubble Space Telescope photometry identify a potential optical companion NS, find evidence that lacks hydrogen. carefully consider number systematic problems, show choices atmospheric composition, interstellar medium abundances, cluster distances can have important effects on inferred NS radius....
Despite the large number of discoveries made recently by Fermi, origins so called unidentified gamma-ray sources remain unknown. The these suggests that among them there could be a population significantly contributes to isotropic background and is therefore crucial understand their nature. first step toward complete comprehension source identify those can associated with blazars, most numerous class extragalactic in sky. Recently, we discovered blazars recognized separated from other using...
Blazars constitute the most interesting and enigmatic class of extragalactic gamma-ray sources dominated by non-thermal emission. In this Letter, we show how WISE infrared data make possible to identify a distinct region [3.4]-[4.6]-[12] micron color-color diagram where thermal radiation are separated from those emission, in particular blazar population. This delineated as Blazar Strip (WBS), it is powerful new diagnostic tool when full survey released. The WBS can be used extract...
Blazars constitute the most enigmatic class of extragalactic gamma-ray sources, and their observational features have been ascribed to a relativistic jet closely aligned line sight. They are generally divided in two main classes: BL Lac objects (BL Lacs) Flat Spectrum Radio Quasars (FSRQs). In case Lacs double bumped spectral energy distribution (SED) is described by Synchrotron Self Compton (SSC) emission, while for FSRQs it interpreted as due External (EC) emission. Recently, we showed...
We report the discovery and detailed monitoring of X-ray emission associated with Type IIb SN 2011dh using data from Swift Chandra satellites, placing it among best-studied supernovae (SNe) to date. further present millimeter radio obtained Submillimeter Array, Combined Array for Research in Millimeter-wave Astronomy, Expanded Very Large during first three weeks after explosion. Combining these observations early optical photometry, we show that panchromatic set is well described by...
This paper investigates the recent stellar merger transient M31LRN 2015 in Andromeda galaxy. We analyze published optical photometry and spectroscopy along with a Hubble Space Telescope detection of color magnitude pre-outburst source. The outburst is consistent dynamically driven ejecta at onset common envelope episode, which eventually leads to complete binary system. light curve appears contain two components: first $\sim10^{-2} M_\odot$ fast by shocks envelope, later, $\sim0.3 further as...
We report on Rossi X-Ray Timing Explorer observations of four type I X-ray bursters, namely, 1E 1724-3045, GS 1826-238, SLX 1735-269, and KS 1731-260. The first three were in a low state, with 1-200 keV luminosities the range ~0.05-0.1LEdd (LEdd: Eddington luminosity for neutron star, LEdd = 2.5 × 1038 ergs s-1), whereas 1731-260 was high ~0.35LEdd. low-state sources have very similar power spectra, displaying high-frequency noise up to ~200 Hz. For 1731-260, its spectrum is dominated by at...