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Title: DETECTION AND IMAGING OF THE CRAB NEBULA WITH THE NUCLEAR COMPTON TELESCOPE

Abstract

The Nuclear Compton Telescope (NCT) is a balloon-borne Compton telescope designed for the study of astrophysical sources in the soft gamma-ray regime (200 keV-20 MeV). NCT's 10 high-purity germanium crossed-strip detectors measure the deposited energies and three-dimensional positions of gamma-ray interactions in the sensitive volume, and this information is used to restrict the initial photon to a circle on the sky using the Compton scatter technique. Thus NCT is able to perform spectroscopy, imaging, and polarization analysis on soft gamma-ray sources. NCT is one of the next generation of Compton telescopes-the so-called compact Compton telescopes (CCTs)-which can achieve effective areas comparable to the Imaging Compton Telescope's with an instrument that is a fraction of the size. The Crab Nebula was the primary target for the second flight of the NCT instrument, which occurred on 2009 May 17 and 18 in Fort Sumner, New Mexico. Analysis of 29.3 ks of data from the flight reveals an image of the Crab at a significance of 4{sigma}. This is the first reported detection of an astrophysical source by a CCT.

Authors:
; ; ; ;  [1]; ; ;  [2]; ; ;  [3];  [4];  [5];  [6];  [7]; ;  [8]; ;  [9];  [10]
  1. Space Sciences Laboratory, University of California, Berkeley, CA 94720 (United States)
  2. Department of Physics, National Tsing Hua University, Hsinchu 30013, Taiwan (China)
  3. Department of Physics, National Central University, Taoyuan 32001, Taiwan (China)
  4. Department of Energy Engineering, National United University, Miaoli 36003, Taiwan (China)
  5. Department of Electrical Engineering, National United University, Miaoli 36003, Taiwan (China)
  6. Department of Electronic Engineering, National United University, Miaoli 36003, Taiwan (China)
  7. Institute of Physics, Academia Sinica, Taipei 11529, Taiwan (China)
  8. Lawrence Berkeley National Laboratory, Berkeley, CA 94720 (United States)
  9. Centre d'Etude Spatiale des Rayonnements (CESR), 31028 Toulouse Cedex 4 (France)
  10. Deutsches Elektronen-Synchrotron (DESY), Notkestr. 85, 22607 Hamburg (Germany)
Publication Date:
OSTI Identifier:
21582996
Resource Type:
Journal Article
Resource Relation:
Journal Name: Astrophysical Journal; Journal Volume: 738; Journal Issue: 1; Other Information: DOI: 10.1088/0004-637X/738/1/8
Country of Publication:
United States
Language:
English
Subject:
79 ASTROPHYSICS, COSMOLOGY AND ASTRONOMY; CRAB NEBULA; GAMMA DETECTION; GAMMA RADIATION; HIGH-PURITY GE DETECTORS; INTERACTIONS; THREE-DIMENSIONAL CALCULATIONS; COSMIC RADIO SOURCES; DETECTION; ELECTROMAGNETIC RADIATION; GE SEMICONDUCTOR DETECTORS; IONIZING RADIATIONS; MEASURING INSTRUMENTS; NEBULAE; RADIATION DETECTION; RADIATION DETECTORS; RADIATIONS; SEMICONDUCTOR DETECTORS; SUPERNOVA REMNANTS

Citation Formats

Bandstra, M. S., Bellm, E. C., Boggs, S. E., Perez-Becker, D., Zoglauer, A., Chang, H.-K., Chiu, J.-L., Liang, J.-S., Chang, Y.-H., Liu, Z.-K., Hung, W.-C., Huang, M.-H. A., Chiang, S. J., Run, R.-S., Lin, C.-H., Amman, M., Luke, P. N., Jean, P., Von Ballmoos, P., and Wunderer, C. B., E-mail: bandstra@ssl.berkeley.edu. DETECTION AND IMAGING OF THE CRAB NEBULA WITH THE NUCLEAR COMPTON TELESCOPE. United States: N. p., 2011. Web. doi:10.1088/0004-637X/738/1/8.
Bandstra, M. S., Bellm, E. C., Boggs, S. E., Perez-Becker, D., Zoglauer, A., Chang, H.-K., Chiu, J.-L., Liang, J.-S., Chang, Y.-H., Liu, Z.-K., Hung, W.-C., Huang, M.-H. A., Chiang, S. J., Run, R.-S., Lin, C.-H., Amman, M., Luke, P. N., Jean, P., Von Ballmoos, P., & Wunderer, C. B., E-mail: bandstra@ssl.berkeley.edu. DETECTION AND IMAGING OF THE CRAB NEBULA WITH THE NUCLEAR COMPTON TELESCOPE. United States. doi:10.1088/0004-637X/738/1/8.
Bandstra, M. S., Bellm, E. C., Boggs, S. E., Perez-Becker, D., Zoglauer, A., Chang, H.-K., Chiu, J.-L., Liang, J.-S., Chang, Y.-H., Liu, Z.-K., Hung, W.-C., Huang, M.-H. A., Chiang, S. J., Run, R.-S., Lin, C.-H., Amman, M., Luke, P. N., Jean, P., Von Ballmoos, P., and Wunderer, C. B., E-mail: bandstra@ssl.berkeley.edu. Thu . "DETECTION AND IMAGING OF THE CRAB NEBULA WITH THE NUCLEAR COMPTON TELESCOPE". United States. doi:10.1088/0004-637X/738/1/8.
@article{osti_21582996,
title = {DETECTION AND IMAGING OF THE CRAB NEBULA WITH THE NUCLEAR COMPTON TELESCOPE},
author = {Bandstra, M. S. and Bellm, E. C. and Boggs, S. E. and Perez-Becker, D. and Zoglauer, A. and Chang, H.-K. and Chiu, J.-L. and Liang, J.-S. and Chang, Y.-H. and Liu, Z.-K. and Hung, W.-C. and Huang, M.-H. A. and Chiang, S. J. and Run, R.-S. and Lin, C.-H. and Amman, M. and Luke, P. N. and Jean, P. and Von Ballmoos, P. and Wunderer, C. B., E-mail: bandstra@ssl.berkeley.edu},
abstractNote = {The Nuclear Compton Telescope (NCT) is a balloon-borne Compton telescope designed for the study of astrophysical sources in the soft gamma-ray regime (200 keV-20 MeV). NCT's 10 high-purity germanium crossed-strip detectors measure the deposited energies and three-dimensional positions of gamma-ray interactions in the sensitive volume, and this information is used to restrict the initial photon to a circle on the sky using the Compton scatter technique. Thus NCT is able to perform spectroscopy, imaging, and polarization analysis on soft gamma-ray sources. NCT is one of the next generation of Compton telescopes-the so-called compact Compton telescopes (CCTs)-which can achieve effective areas comparable to the Imaging Compton Telescope's with an instrument that is a fraction of the size. The Crab Nebula was the primary target for the second flight of the NCT instrument, which occurred on 2009 May 17 and 18 in Fort Sumner, New Mexico. Analysis of 29.3 ks of data from the flight reveals an image of the Crab at a significance of 4{sigma}. This is the first reported detection of an astrophysical source by a CCT.},
doi = {10.1088/0004-637X/738/1/8},
journal = {Astrophysical Journal},
number = 1,
volume = 738,
place = {United States},
year = {Thu Sep 01 00:00:00 EDT 2011},
month = {Thu Sep 01 00:00:00 EDT 2011}
}
  • The Crab Pulsar and Nebula are the remnants of the explosion of the supernova SN1054, which was observed by Chinese astronomers. Previously detected by EGRET, the Crab Pulsar and Nebula have been extensively observed in the gamma-ray energy band by the Large Area Telescope (LAT) onboard the Fermi satellite. The data collected by the LAT during its early operation stage have allowed a detailed measurement of the fluxes and of the energy spectra of both sources. The pulsar spectrum is consistent with the EGRET measurement in the region below 1 GeV and is well described by a power law withmore » exponential cutoff at a few GeV. The nebula spectrum is well modeled by a sum of two power laws, identified respectively as the falling edge of the synchrotron and the rising edge of the inverse Compton components, and is in agreement with the observations from Earth-based telescopes.« less
  • We report on gamma-ray observations of the Crab Pulsar and Nebula using 8 months of survey data with the Fermi Large Area Telescope (LAT). The high quality light curve obtained using the ephemeris provided by the Nancay and Jodrell Bank radio telescopes shows two main peaks stable in phase with energy. The first gamma-ray peak leads the radio main pulse by (281 +- 12 +- 21) mus, giving new constraints on the production site of non-thermal emission in pulsar magnetospheres. The first uncertainty is due to gamma-ray statistics, and the second arises from the rotation parameters. The improved sensitivity andmore » the unprecedented statistics afforded by the LAT enable precise measurement of the Crab Pulsar spectral parameters: cut-off energy at E{sub c} = (5.8 +- 0.5 +- 1.2) GeV, spectral index of GAMMA = (1.97 +- 0.02 +- 0.06) and integral photon flux above 100 MeV of (2.09 +- 0.03 +- 0.18) x 10{sup -6} cm{sup -2} s{sup -1}. The first errors represent the statistical error on the fit parameters, while the second ones are the systematic uncertainties. Pulsed gamma-ray photons are observed up to approx 20 GeV which precludes emission near the stellar surface, below altitudes of around 4-5 stellar radii in phase intervals encompassing the two main peaks. A detailed phase-resolved spectral analysis is also performed: the hardest emission from the Crab Pulsar comes from the bridge region between the two gamma-ray peaks while the softest comes from the falling edge of the second peak. The spectrum of the nebula in the energy range 100 MeV-300 GeV is well described by the sum of two power laws of indices GAMMA{sub sync} = (3.99 +- 0.12 +- 0.08) and GAMMA{sub IC} = (1.64 +- 0.05 +- 0.07), corresponding to the falling edge of the synchrotron and the rising edge of the inverse Compton (IC) components, respectively. This latter, which links up naturally with the spectral data points of Cherenkov experiments, is well reproduced via IC scattering from standard magnetohydrodynamic nebula models, and does not require any additional radiation mechanism.« less
  • Here, we report on γ-ray observations of the Crab Pulsar and Nebula using 8 months of survey data with the Fermi Large Area Telescope (LAT). The high quality light curve obtained using the ephemeris provided by the Nançay and Jodrell Bank radio telescopes shows two main peaks stable in phase with energy. The first γ-ray peak leads the radio main pulse by (281 ± 12 ± 21) μs, giving new constraints on the production site of non-thermal emission in pulsar magnetospheres. The first uncertainty is due to γ-ray statistics, and the second arises from the rotation parameters. The improved sensitivitymore » and the unprecedented statistics afforded by the LAT enable precise measurement of the Crab Pulsar spectral parameters: cut-off energy at E c = (5.8 ± 0.5 ± 1.2) GeV, spectral index of Γ = (1.97 ± 0.02 ± 0.06) and integral photon flux above 100 MeV of (2.09 ± 0.03 ± 0.18) × 10 –6 cm –2 s –1. The first errors represent the statistical error on the fit parameters, while the second ones are the systematic uncertainties. Pulsed γ-ray photons are observed up to ~ 20 GeV which precludes emission near the stellar surface, below altitudes of around 4-5 stellar radii in phase intervals encompassing the two main peaks. We also performed a detailed phase-resolved spectral analysis : the hardest emission from the Crab Pulsar comes from the bridge region between the two γ-ray peaks while the softest comes from the falling edge of the second peak. Furthermore, the spectrum of the nebula in the energy range 100 MeV-300 GeV is well described by the sum of two power laws of indices Γ sync = (3.99 ± 0.12 ± 0.08) and Γ IC = (1.64 ± 0.05 ± 0.07), corresponding to the falling edge of the synchrotron and the rising edge of the inverse Compton (IC) components, respectively. This latter, which links up naturally with the spectral data points of Cherenkov experiments, is well reproduced via IC scattering from standard magnetohydrodynamic nebula models, and does not require any additional radiation mechanism.« less