Science Release
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The velocity field image of the nearby edge-on galaxy NGC 3556, constructed from our multi-slit narrow-band spectroscopic data, clearly shows rotating features with a typical maximum rotation velocity of roughly 150 km/s.
CosmicCanvas was used to assign an equiluminance colour mapping to the MDM velocity field image. These equal intensity colours spanned 180 degrees on the colour wheel from turquoise to orange. The chroma was adjusted so that perceptually the orange, representing redshift, visually recedes while the turquoise, representing blueshift, approaches the viewer. Using GIMP, this image was "multiplied" by a greyscale version of the APO H-alpha image. GIMP's "addition" blending mode merged this combined image with a combined SDSS image of u- g- and r-filters assigned blue, green and red respectively. Note that before assigning colours the .fits data were intensity-scaled using logarithmic plus bias/contrast adjustments in CARTA. Further intensity adjustments were carried out in GIMP.
Citations:
CosmosCanvas: English, J., Richardson, M. L. A., Ferrand, G., and Deg, N. 2023, version 1, Astrophysics Source Code Library, record ID ascl:2401.005
Carta: A. Comrie et al. 2021, "CARTA: The Cube Analysis and Rendering Tool for Astronomy", DOI 10.5281/zenodo.3377984
GIMP: The GIMP Development Team, 2019. GIMP, Available at https://www.gimp.org
Jayanne English (U. Manitoba), Liyuan Lu (XMU & PMO), Jiangtao Li (PMO)/MDM/APO/SDSS
2024Aug07
eDIG-Changes. II. Project Design and Initial Results on NGC 3556 (publication link)
