Broadband x-ray imaging and spectroscopy of the crab nebula and pulsar with NuSTAR

Kristin K. Madsen, Stephen Reynolds, Fiona Harrison, Hongjun An, Steven Boggs, Finn Erland Christensen, William W. Craig, Chris L. Fryer, Brian W. Grefenstette, Charles J. Hailey

    Research output: Contribution to journalJournal articleResearchpeer-review

    565 Downloads (Pure)

    Abstract

    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 ~9 keV in the spectral photon index of the torus structure with a steepening characterized by ΔΓ ~ 0.25. We also confirm a previously reported steepening in the pulsed spectrum, and quantify it with a broken power law with break energy at ~12 keV and ΔΓ ~ 0.27. We present spectral maps of the inner 100" of the remnant and measure the size of the nebula as a function of energy in seven bands. These results find that the rate of shrinkage with energy of the torus size can be fitted by a power law with an index of γ = 0.094 ± 0.018, consistent with the predictions of Kennel and Coroniti. The change in size is more rapid in the NW direction, coinciding with the counter-jet where we find the index to be a factor of two larger. NuSTAR observed the Crab during the latter part of a γ-ray flare, but found no increase in flux in the 3-78 keV energy band.
    Original languageEnglish
    Article number66
    JournalAstrophysical Journal
    Volume801
    Issue number1
    Number of pages14
    ISSN0004-637X
    DOIs
    Publication statusPublished - 2015

    Keywords

    • Pulsars: individual (Crab)
    • Stars: neutron
    • X-rays: individual (Crab)

    Fingerprint

    Dive into the research topics of 'Broadband x-ray imaging and spectroscopy of the crab nebula and pulsar with NuSTAR'. Together they form a unique fingerprint.

    Cite this