M33 in Radio and Optical

This image of the Triangulum Galaxy was created by combining optical data from the National Science Foundation's 0.9-meter telescope on Kitt Peak in Arizona with radio data from the National Science Foundation's Very Large Array (VLA) telescope in New Mexico and the Westerbork Synthesis Radio Telescope (WSRT) in the Netherlands. Also known as M33, the Triangulum Galaxy is part of the Local Group of galaxies, which includes the Andromeda Galaxy (M31) and our galaxy, the Milky Way. M33 is over thirty thousand light years across, and more than two million light years away. The optical data in this image show the many stars within the galaxy as well as reddish star forming regions that are filled with hot Hydrogen gas. The radio data reveal the cool Hydrogen gas within the galaxy, gas which cannot be seen with an optical telescope. Combined together, the radio and optical give a more comprehensive view of star formation in this galaxy. The color image was generated by combining images taken with the 0.9-meter telescope through four filters (B, V, I and Hydrogen-alpha) and 21cm neutral Hydrogen data taken with the VLA and WSRT (shown in blue-violet). The image is one square degree in field of view, roughly five times the size of the Moon. A very high resolution (8107 x 8270 pixels) version of this image is available on request.

The radio data were obtained from VLA observations taken both in its B-array and CS-array configurations, with a spatial resolution of 10" and velocity resolution of 1.3 km/s. The VLA data have been supplemented by total power observations obtained at the Westerbork Synthesis Radio Telescope.

Legacy Astronomical Images

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

Legacy Astronomical Image

M33

NOAO/AURA/NSF

Travis Rector, David Thilker, Robert Braun

Very Large Array (VLA)

WSRT

1998-08-15

spectral line

21 cm

1420.4 MHz

HI

RA 1:33:51.020, Dec: 30:39:36.700 (J2000)

1.000000 x 1.000000 degrees

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

Galaxies Series

Spiral Unit