Future MeerKAT Installation Completes Spectral Analysis of NGC 3109

The KAT-7 radio telescope is probably the largest found in the southern hemisphere. Eventually, it will be expanded to include technology that makes up an even larger system called the MeerKAT. It should remain the largest unit down south until the Square Kilometer Array is finished around 2024. Though one could argue that KAT-7 is still under construction, it is already yielding some pretty amazing results. The device has observed radio emissions from neutral hydrogen gas in the NGC 3109 galaxy.

NGC 3109

NGC 3109 is classified as a Magellanic type irregular galaxy, but it may in fact be a small spiral galaxy. If it is a spiral galaxy, it would be the smallest in the Local Group (dwarf galaxy). NGC 3109 has a mass of about 2.3×109 times the mass of the Sun, of which 20% is in the form of neutral hydrogen. It is oriented edge-on from our point of view, and may contain a disk and a halo. The disk appears to be composed of stars of all ages, whereas the halo contains only very old and metal-poor stars. NGC 3109 does not appear to possess a galactic nucleus.It is about 4.3 million light-years from Earth and is located in the constellation of Hydra. In areas where the gas is moving in a relative direction towards the point of observation, the spectral lines are Doppler shifted upward. In areas where the opposite is true, the spectral lines are downshifted. This means that astronomers can ultimately map the direction in which the gas in the galaxy is moving.

Mapping the universe with neutral hydrogen substances is one of the primary missions for the SKA and MeerKAT installations. The universe is constantly expanding, and this means that distant galaxies are moving away from one another. Spectral analysis should help to calculate just how far away these galaxies are.

NGC 3109

Image Credit: NGC 3109 by GALEX

Reference:

G. Pietrzynski, W. Gieren, A. Udalski, I. Soszynski, F. Bresolin, R. P. Kudritzki, R. Mennickent, & M. Szymanski (2006). The Araucaria Project. A Wide-Field Photometric Survey for Cepheid
Variables in NGC 3109 Astrophys.J.648:366-374,2006 arXiv: astro-ph/0605226v1

Lee, M. (1993). The distance to nearby galaxy NGC 3109 based on the tip of the red giant branch The Astrophysical Journal, 408 DOI: 10.1086/172598

Musella, I., Piotto, G., & Capaccioli, M. (1997). On the cepheid variables of nearby galaxies. III. NGC 3109. The Astronomical Journal, 114 DOI: 10.1086/118528

Barnes, D., & de Blok, W. (2001). On the Neutral Gas Content and Environment of NGC 3109 and the Antlia Dwarf Galaxy The Astronomical Journal, 122 (2), 825-829 DOI: 10.1086/321170

KAT-7. (n.d.). Square Kilometre Array (SKA) Africa. Retrieved March 16, 2012, from http://www.ska.ac.za/media/kat7.php

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