Speaker
Dr
George Sonneborn
(NASA Goddard Space Flight Center)
Description
The nature and quantity of dust produced in supernovae (SNe) is still poorly
understood. Recent IR observations of freshly-formed dust in supernova remnants
(SNRs) have yielded significantly lower dust masses than predicted by theoretical
models and observations high-redshift galaxies. The Crab Nebula's pulsar wind is
thought to be sweeping up freshly-formed SN dust along with the SN ejecta. The
evidence for this dust was found in the form of an IR bump in the integrated spectrum
of the Crab and in extinction against the synchrotron nebula that revealed the
presence of dust in the filament cores. We present the first spatially-resolved
emission spectra of dust in the Crab Nebula acquired with the Spitzer Space
Telescope. The IR spectra are dominated by synchrotron emission and show forbidden
line emission from both sides of the expanding nebula, including emission from [S
III], [Si II], [Ne II], [Ne III], [Ne V], [Ar III], [Ar V], [Fe II], and [Ni II]. We
extrapolated a synchrotron spectral data cube from the Spitzer 3.6 and 4.5 micron
images, and subtracted this contribution from our 15-40 micron spectral data to
produce a map of the residual continuum emission from dust. The emission appears to
be concentrated along the ejecta filaments and is well described by astronomical
silicates at an average temperature of 65 K. The estimated mass of dust in the Crab
Nebula is 0.008 solar masses.
Primary author
Dr
George Sonneborn
(NASA Goddard Space Flight Center)
Co-authors
Dr
Eli Dwek
(NASA Goddard Space Flight Center)
Dr
Patrick Slane
(Harvard-Smithsonian Center for Astrophysics)
Dr
Rick Arendt
(NASA Goddard Space Flight Center)
Dr
Robert Gehrz
(University of Minesota)
Dr
Tea Temim
(NASA Goddard Space Flight Center)
