The late-type galaxy NGC 4303 ( M61 ) is one of the most intensively studied barred galaxies in the Virgo Cluster .
Its prominent enhanced star formation throughout large areas of the disk can be nicely studied due to its low inclination of about 27° .

We present observations of NGC 4303 with the ROSAT PSPC and HRI in the soft X-ray ( 0.1–2.4 keV ) .
The bulk of the X-ray emission is located at the nuclear region .
It contributes more than 80 % to the total observed soft X-ray flux .
The extension of the central X-ray source and the L _ { X } / L _ { H \alpha } ratio point to a low luminous AGN ( LINER ) with a circumnuclear star-forming region .
Several separate disk sources can be distinguished with the HRI , coinciding spatially with some of the most luminous H ii regions outside the nucleus of NGC 4303 .
The total star formation rate amounts to 1–2 M _ { \sun } yr ^ { -1 } .
The X-ray structure follows the distribution of star formation with enhancement at the bar-typical patterns .

The best spectral fit consists of a power-law component ( AGN and HMXBs ) and a thermal plasma component of hot gas from supernova remnants and superbubbles .
The total 0.1–2.4 keV luminosity of NGC 4303 amounts to 5 \times 10 ^ { 40 } erg s ^ { -1 } , consistent with comparable galaxies , like e.g .
NGC 4569 .