Star Formation in NGC 1187


Where does global star formation end in spiral galaxies? The above multi-wavelength image of NGC1187 combines H alpha emission (red), visible light in the R-band (white), and HI 21cm gas emission (blue). The H alpha and R-band data were obtained with the WIYN 3.5m, while the HI data were obtained with the Very Large Array. Each wavelength probes a different aspect of the galaxy; the H alpha emission traces recent star formation, the visible light traces past star formation, which is now seen as the old stellar disk, and the HI emission indicates where there is fuel for creating new stars.
Narrowband H alpha emission and continuum, R-band, and HI 21 cm line emission are combined in the above RGB image to show star formation, the stellar disk, and HI. The H alpha and R-band data were obtained with the WIYN 3.5m. The images represent a total integration time of 6000 seconds for the OFF- band, 7200 seconds for the ON-band, and 360 seconds for the R-band exposures. The seeing for each exposure is about 1.1, 1.1, 0.95 arcseconds respectively. The HI data were obtained with the VLA in DnC configuration, 380 minutes on source, with a beam size of 40.9x28.6 arcseconds.


Legacy Astronomical Images


NRAO/AUI/NSF does not hold full copyright for this image. Contact the archivist for details.


Legacy Astronomical Image

Object Name

NGC 1187

Photo Credit

A. C. Boley and L. van Zee, Indiana University; D. Schade and S. C?t?, Herzberg Institute for Astrop


L. van Zee, D. Schade, S. Csto


Very Large Array (VLA)

Observation Date


Type of Observation

spectral line

Center of Image

RA 3:2:38.000, Dec: -22:51:33.000 (J2000)

Field of View

0.125000 x 0.125000 degrees


Contact the archivist for a high resolution tif of this image.


Galaxies Series


Spiral Unit


Legacy Astronomical Images, “Star Formation in NGC 1187,” NRAO Archives, accessed December 3, 2021,