NGC 4522 BVR
Broadband color image of the Virgo Cluster spiral
galaxy NGC4522. Most of the light in this picture
arises from stars. The dark lanes are due to dust
which blocks some of the starlight. This highly
inclined galaxy has a relatively normal
distribution of old stars, but bright, blue
newly-formed star clusters can be seen embedded
within gas filaments which emerge from the disk
plane toward the NW.
Image from WIYN 3.5-meter telescope.
|
NGC 4522 H-alpha
H-alpha image of the Virgo
Cluster spiral galaxy
NGC4522. H-alpha emission
arises from hot ionized gas
surrounding recently formed
massive stars. This image
is to the same scale as the
broadband image to the left.
Image from WIYN 3.5-meter
telescope.
|
NGC 4522 H-alpha and R
H-alpha and broadband (R band) optical maps of the Virgo Cluster
spiral galaxy NGC4522. The galaxy has been rotated for this figure.
(a) The top panel shows grayscale and contour maps of H-alpha
emission. Note that there is no H-alpha emission, and therefore
no ionized gas and no star formation, in the outer disk.
(b) The middle panel shows grayscale and contour maps of R-band
emission. The distribution of starlight appears normal for an
inclined spiral disk galaxy.
(c) The bottom panel shows an overlay of the H-alpha map (grayscale)
on the R-band map (contours). Note that the distributions of stars
and gas are very different! There is no gas in the outer disk, but
there are gas filaments emerging from the plane of the disk. This is
gas in the process of leaving the galaxy, as it is stripped by the
ram pressure force exerted by gas in the intracluster medium.
Images from WIYN 3.5-meter telescope.
|
|