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Description
We present HI observations of the jellyfish galaxy, JO201, a massive galaxy falling along the line-of-sight towards the centre of a rich cluster, A85 at a high velocity. Its H{alpha} emission shows a ~40kpc tail confined closely to its stellar disc and a ~100kpc tail extending further out. We find HI emission coinciding only with the shorter clumpy H{alpha} tail while no HI emission is detected along the ~100kpc Ha tail. In total, we measure an HI mass of M_HI_=1.65x10^+9^M_{sun}_, which is about 60% lower than expected based on its stellar mass and stellar surface density. We compared JO201 to another jellyfish in the GASP sample, JO206, and find that they are similarly HI-deficient. The global star formation rate (SFR) analysis of JO201 suggests that its observed SFR would be expected if it had 10x its current HI mass. The disc is the main contributor of the high star formation efficiency at a given HI gas density for both galaxies, but their tails also show higher star formation efficiencies compared to the outer regions of field galaxies. Generally, we find that JO201 and JO206 are similar based on their HI content, stellar mass and star formation rate. This finding is unexpected considering their different environments. A toy model comparing the ram pressure of the ICM versus the restoring forces of these galaxies suggests that the ram pressure strength exerted on them could be comparable if we consider their 3D orbital velocities and radial distances relative to the clusters.
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