We present a deep VLA search for HI emission from the low-luminosity Virgo Cluster elliptical galaxy NGC 4476 , which contains 1.1 \times 10 ^ { 8 } M _ { \odot } of molecular gas in an undisturbed disk in regular rotation .
No HI was detected .
The rms noise in the final image corresponds to a 3 \sigma column density sensitivity of 1.2 \times 10 ^ { 20 } cm ^ { -2 } at the position of NGC 4476 , averaged over the 4 kpc beam .
The total HI mass is less than 1.5 \times 10 ^ { 7 } M _ { \odot } .
If we compare our HI upper limit to the H _ { 2 } content , we find that NGC 4476 is extremely deficient in HI compared to other galaxies detected in these two species .
The H _ { 2 } /HI mass ratio for NGC 4476 is > 7 , whereas typical H _ { 2 } /HI ratios for elliptical galaxies detected in both HI and H _ { 2 } are < 2 .
Based on this extreme HI deficiency and the intra-cluster medium ( ICM ) density at the projected distance from M87 we argue that either NGC 4476 has undergone ram-pressure stripping while traveling through the Virgo cluster core or its average molecular gas density is larger and its interstellar UV field is smaller than in typical spiral galaxies .
NGC 4476 is located 12′ in projection from M87 , which causes extreme continuum confusion problems .
We also discuss in detail the techniques used for continuum subtraction .
The spectral dynamic range of our final image is 50,000 to 1 .