| Description: | The picture shows WSRT observations of the neutral hydrogen gas in galaxy NGC 4414, overlaid on a background optical image. NGC 4414 was observed as part of the HALOGAS survey. This deep survey of nearby galaxies aims to help solve the riddle of where the gas in galaxies comes from. Galaxies do not have enough gas to sustain their current rate of star formation and must be resupplied from somewhere.
The HALOGAS observations showed that the optically very normal looking galaxy actually has an extended and disturbed neutral hydrogen disk, as shown the picture. This distribution can be modelled as a so-called "U-shaped warp" - what we are seeing is that the outer, low-density parts of the disk get pushed and slowed down by the intra-galactic medium as the galaxy moves through space, resulting in the disk looking like a dinner plate. These new, deep observations of NGC 4414 presented here show that even apparently undisturbed galaxies are interacting with their environment. For more information see http://adsabs.harvard.edu/abs/2014A%26A...566A..80D |
