ChandraSpatially Resolved Spectroscopic Study and Multiwavelength Imaging of the Supernova Remnant 3C 397 (G41.1−0.3)

(Abridged) We present a Chandra observation of the supernova remnant (SNR) 3C397 (G41.1-0.3) obtained with ACIS-S. Previous studies of this SNR have shownthat it harbors a central X-ray `hot spot' suggestive of a compact objectassociated with 3C 397. With the Chandra data, we can rule out the nature ofthe hot spot as a pulsar or a pulsar wind nebula, and put an upper limit on theflux of a hidden compact object of F (0.5--10 keV)~6E-13 erg/cm2/s. We foundtwo point sources in the Chandra field. We argue that none of them isassociated with 3C 397; and that the hard source, CXO J190741.2+070650, is anewly discovered AGN. The Chandra image reveals arcseconds-scale clumps andknots which are strongly correlated with the radio VLA image, except for theX-ray hot spot. Our Chandra spatially resolved spectroscopic study shows thatone-component models are inadequate, and that at least two non-equilibriumionization thermal components are needed to fit the spectra of each selectedregion. The derived average spectral parameters are consistent with theprevious global ASCA fits performed by Safi-Harb et al. (2000). However, thehard component requires a high abundance of Fe indicating the presence of hotFe ejecta. When comparing the eastern with the western lobe, we find that thecolumn density, the brightness, and the ionization timescales are generallyhigher for the western side. This result, combined with our study of the 3C397environs at millimeter wavelengths, indicate a denser medium to the west of theSNR. Our multi-wavelength imaging and spectral study favors the scenario where3C 397 is a ~5,300-year old SNR expanding in a medium with a marked densitygradient, and which is likely to be encountering a molecular cloud on thewestern side. We propose that 3C 397 will evolve into a mixed-morphology SNR.