ACIS X-ray Spectrum
This image illustrates the X-ray afterglow spectrum of GRB991216 obtained with the Advanced CCD Imaging Spectrometer (ACIS) instrument aboard the Chandra X-ray Observatory on December 18, 1999. The ACIS instrument is an array of charged coupled devices (CCDs). This instrument is especially useful because it can make X-ray images, and at the same time, measure the energy of each incoming X-ray, as depicted in this image.
(Credit: NASA/CNR/L.Piro et al)

Optical image of field around GRB991216
This image is an optical view of the area around GRB991216. The optical transient believed to be the GRB afterglow is indicated with an arrow.
(Credit: S.Jha et al. (Harvard-Smithsonian Center for Astrophysics))

Chandra HETG Spectrum
Shown here is the X-ray afterglow spectrum of GRB991216 obtained with Chandra's High Energy Grating Spectrometer (HETG). The HETG is one of two instruments aboard Chandra (the other being the Low Energy Grating Spectrometer) dedicated to high-resolution spectroscopy and can be used in conjunction with the ACIS or High Resolution Camera.
(Credit: NASA/CNR/L.Piro et al)

X-ray image of GRB991216
Taken with the ACIS instrument, this CCD image shows the observed X-ray afterglow.
(Credit: NASA/CXC/Piro et al.)

Chandra X-ray Image with Scale Bar

Scale bar = 10 arcsec
(Credit: NASA/CNR/L.Piro et al.)