An observation of Mrk 478 using the Chandra Low Energy Transmission Grating Spectrometer is presented .
The source exhibited 30-40 % flux variations on timescales of \sim 10 ^ { 4 } s together with a slow decline in the spectral softness over the full 80 ks observation .
The 0.15–3.0 keV spectrum is well fitted by a single power law with photon index \Gamma = 2.91 \pm 0.03 .
Combined with high energy data from BeppoSAX , the spectrum from 0.15 to 10 keV is well fit as the sum of two power laws with \Gamma = 3.03 \pm 0.04 , which dominates below 2 keV and 1.4 \pm 0.2 , which dominates above 2 keV ( quoting 90 % confidence uncertainties ) .
No significant emission or absorption features are detected in the high resolution spectrum , supporting our previous findings using the Extreme Ultraviolet Explorer but contradicting the claims of emission lines by Hwang & Bowyer ( 1997 ) .
There is no evidence of a warm absorber , as found in the high resolution spectra of many Sy 1 galaxies including others classified as narrow line Sy 1 galaxies such as Mrk 478 .
We suggest that the X-ray continuum may result from Comptonization of disk thermal emission in a hot corona through a range of optical depths .