Molecular Clouds Associated with Supernova Remnants in the Large Magellanic Cloud

N132D

The grayscale shows the ROSAT X-ray image of the supernova remnant (SNR) N132D overlaid with contours of X-ray emission at levels of 0.54, 1.1, 1.6, 2.1, 2.7, 3.2, and 3.8 counts s-1 arcmin-2. The set of contours to the south of the SNR show the velocity integrated CO emission (J= 2-1 rotational transition at 230.5 GHz) obtained at the Swedish-ESO Submillimeter Telescope. The grid pattern for the CO observations is shown. The CO contours are 5.0, 8.3, 11.7, 15.0, 18.3, 21.7, 25.0, 28.3, and 31.7 K km s-1. The amount of gas in this giant molecular cloud is 3x105 solar masses. Coordinates are in epoch B1950.
Photo Credit: John P. Hughes, Rutgers University

N49

The grayscale shows the ROSAT X-ray image of the supernova remnant (SNR) N49 overlaid with contours of X-ray emission at levels of 0.35, 0.87, 1.4, 1.9, 2.4, 3.0, and 3.5 counts s-1 arcmin-2. The CO emission here appears at the eastern limb of the remnant, where the X-rays are brightest. The CO emission (also obtained at the SEST) is much weaker for this remnant; contours are 1.0, 1.3, 1.7, 2.0, 2.3, and 2.7 K km s-1. Again, the grid pattern for the CO observations is shown. The mass of gas in this molecular cloud is estimated to be only 104 solar masses.
Photo Credit: John P. Hughes, Rutgers University

Discussion

The velocities derived for the molecular clouds near N49 and N132D, +286.0 and +264.0 km/s, agree well with the previously known velocities of the associated SNRs. The ROSAT X-ray images presented above clearly show that the ambient density into which the remnants are expanding appears to be significantly increased in the direction of the clouds. Taken together these observations indicate a physical association between the remnants and their respective, presumably natal, molecular clouds. The association of N49 and N132D with dense regions of molecular material means that both were likely products of short-lived progenitors that exploded as core-collapse supernovae. For more details about this work please see the article "Supernova Remnants Associated with Molecular Clouds in the Large Magellanic Cloud" by Banas, Hughes, Bronfman, and Nyman in the Astrophysical Journal.
Please send any comments on this page to Jack Hughes, jph@physics.rutgers.edu.

Revised October 3, 1997