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Title: NO TIME FOR DEAD TIME: TIMING ANALYSIS OF BRIGHT BLACK HOLE BINARIES WITH NuSTAR

Abstract

Timing of high-count-rate sources with the NuSTAR Small Explorer Mission requires specialized analysis techniques. NuSTAR was primarily designed for spectroscopic observations of sources with relatively low count rates rather than for timing analysis of bright objects. The instrumental dead time per event is relatively long (∼2.5 msec) and varies event-to-event by a few percent. The most obvious effect is a distortion of the white noise level in the power density spectrum (PDS) that cannot be easily modeled with standard techniques due to the variable nature of the dead time. In this paper, we show that it is possible to exploit the presence of two completely independent focal planes and use the cospectrum, the real part of the cross PDS, to obtain a good proxy of the white-noise-subtracted PDS. Thereafter, one can use a Monte Carlo approach to estimate the remaining effects of dead time, namely, a frequency-dependent modulation of the variance and a frequency-independent drop of the sensitivity to variability. In this way, most of the standard timing analysis can be performed, albeit with a sacrifice in signal-to-noise ratio relative to what would be achieved using more standard techniques. We apply this technique to NuSTAR observations of the black holemore » binaries GX 339–4, Cyg X-1, and GRS 1915+105.« less

Authors:
;  [1]; ; ; ;  [2]; ; ;  [3];  [4];  [5]; ;  [6];  [7];  [8];  [9];  [10];  [11];  [12];  [13] more »; « less
  1. Université de Toulouse, UPS-OMP, IRAP, Toulouse F-31400 (France)
  2. Cahill Center for Astronomy and Astrophysics, Caltech, Pasadena, CA 91125 (United States)
  3. Space Sciences Laboratory, University of California, Berkeley, CA 94720 (United States)
  4. Dr. Karl-Remeis-Sternwarte and ECAP, Sternwartstrasse 7, D-96049 Bamberg (Germany)
  5. DTU Space, National Space Institute, Technical University of Denmark, Elektrovej 327, DK-2800 Lyngby (Denmark)
  6. Institute of Astronomy, University of Cambridge, Madingley Road, Cambridge CB3 0HA (United Kingdom)
  7. Department of Physics, Durham University, South Road DH1 3LE (United Kingdom)
  8. Columbia Astrophysics Laboratory, Columbia University, New York, NY 10027 (United States)
  9. Department of Physics, Texas Tech University, Lubbock, TX 79409 (United States)
  10. Department of Astronomy, University of Michigan, 500 Church Street, Ann Arbor, MI 48109-1042 (United States)
  11. CRESST, UMBC, and NASA GSFC, Code 661, Greenbelt, MD 20771 (United States)
  12. Jet Propulsion Laboratory, California Institute of Technology, Pasadena, CA 91109 (United States)
  13. Anton Pannekoek Institute, University of Amsterdam, Science Park 904, 1098 XH Amsterdam (Netherlands)
Publication Date:
OSTI Identifier:
22522118
Resource Type:
Journal Article
Resource Relation:
Journal Name: Astrophysical Journal; Journal Volume: 800; Journal Issue: 2; Other Information: Country of input: International Atomic Energy Agency (IAEA)
Country of Publication:
United States
Language:
English
Subject:
79 ASTROPHYSICS, COSMOLOGY AND ASTRONOMY; ACCRETION DISKS; BINARY STARS; BLACK HOLES; COUNTING RATES; DATA ANALYSIS; DEAD TIME; ENERGY SPECTRA; FREQUENCY DEPENDENCE; MODULATION; MONTE CARLO METHOD; POWER DENSITY; SENSITIVITY; SIGNAL-TO-NOISE RATIO; X RADIATION

Citation Formats

Bachetti, Matteo, Barret, Didier, Harrison, Fiona A., Cook, Rick, Grefenstette, Brian W., Fürst, Felix, Tomsick, John, Boggs, Steven E., Craig, William W., Schmid, Christian, Christensen, Finn E., Fabian, Andrew C., Kara, Erin, Gandhi, Poshak, Hailey, Charles J., Maccarone, Thomas J., Miller, Jon M., Pottschmidt, Katja, Stern, Daniel, Uttley, Phil, E-mail: matteo.bachetti@irap.omp.eu, and and others. NO TIME FOR DEAD TIME: TIMING ANALYSIS OF BRIGHT BLACK HOLE BINARIES WITH NuSTAR. United States: N. p., 2015. Web. doi:10.1088/0004-637X/800/2/109.
Bachetti, Matteo, Barret, Didier, Harrison, Fiona A., Cook, Rick, Grefenstette, Brian W., Fürst, Felix, Tomsick, John, Boggs, Steven E., Craig, William W., Schmid, Christian, Christensen, Finn E., Fabian, Andrew C., Kara, Erin, Gandhi, Poshak, Hailey, Charles J., Maccarone, Thomas J., Miller, Jon M., Pottschmidt, Katja, Stern, Daniel, Uttley, Phil, E-mail: matteo.bachetti@irap.omp.eu, & and others. NO TIME FOR DEAD TIME: TIMING ANALYSIS OF BRIGHT BLACK HOLE BINARIES WITH NuSTAR. United States. doi:10.1088/0004-637X/800/2/109.
Bachetti, Matteo, Barret, Didier, Harrison, Fiona A., Cook, Rick, Grefenstette, Brian W., Fürst, Felix, Tomsick, John, Boggs, Steven E., Craig, William W., Schmid, Christian, Christensen, Finn E., Fabian, Andrew C., Kara, Erin, Gandhi, Poshak, Hailey, Charles J., Maccarone, Thomas J., Miller, Jon M., Pottschmidt, Katja, Stern, Daniel, Uttley, Phil, E-mail: matteo.bachetti@irap.omp.eu, and and others. Fri . "NO TIME FOR DEAD TIME: TIMING ANALYSIS OF BRIGHT BLACK HOLE BINARIES WITH NuSTAR". United States. doi:10.1088/0004-637X/800/2/109.
@article{osti_22522118,
title = {NO TIME FOR DEAD TIME: TIMING ANALYSIS OF BRIGHT BLACK HOLE BINARIES WITH NuSTAR},
author = {Bachetti, Matteo and Barret, Didier and Harrison, Fiona A. and Cook, Rick and Grefenstette, Brian W. and Fürst, Felix and Tomsick, John and Boggs, Steven E. and Craig, William W. and Schmid, Christian and Christensen, Finn E. and Fabian, Andrew C. and Kara, Erin and Gandhi, Poshak and Hailey, Charles J. and Maccarone, Thomas J. and Miller, Jon M. and Pottschmidt, Katja and Stern, Daniel and Uttley, Phil, E-mail: matteo.bachetti@irap.omp.eu and and others},
abstractNote = {Timing of high-count-rate sources with the NuSTAR Small Explorer Mission requires specialized analysis techniques. NuSTAR was primarily designed for spectroscopic observations of sources with relatively low count rates rather than for timing analysis of bright objects. The instrumental dead time per event is relatively long (∼2.5 msec) and varies event-to-event by a few percent. The most obvious effect is a distortion of the white noise level in the power density spectrum (PDS) that cannot be easily modeled with standard techniques due to the variable nature of the dead time. In this paper, we show that it is possible to exploit the presence of two completely independent focal planes and use the cospectrum, the real part of the cross PDS, to obtain a good proxy of the white-noise-subtracted PDS. Thereafter, one can use a Monte Carlo approach to estimate the remaining effects of dead time, namely, a frequency-dependent modulation of the variance and a frequency-independent drop of the sensitivity to variability. In this way, most of the standard timing analysis can be performed, albeit with a sacrifice in signal-to-noise ratio relative to what would be achieved using more standard techniques. We apply this technique to NuSTAR observations of the black hole binaries GX 339–4, Cyg X-1, and GRS 1915+105.},
doi = {10.1088/0004-637X/800/2/109},
journal = {Astrophysical Journal},
number = 2,
volume = 800,
place = {United States},
year = {Fri Feb 20 00:00:00 EST 2015},
month = {Fri Feb 20 00:00:00 EST 2015}
}