H i in the Giant Elliptical Galaxy NGC 4406 (original) (raw)

ADS

Abstract

The Arecibo 305 m radio telescope was used to make 21 cm measurements of NGC 4406, an elliptical galaxy containing 10^10^ M_sun_ of hot diffuse gas. The H I decreases by a factor of 3 one beamwidth from the center (3.5'; 20.4 kpc for d = 20 Mpc) and by an order of magnitude two beamwidths from the center. Excess H I emission is seen in the X-ray tail, but not in dust-rich regions. The H I measurements do not support the suggestion that the X-ray tail is hot gas being stripped from the galaxy. The velocities of the peaks of the emission differ by less than 20 km s^-1^ for observations separated by more than 40 kpc, indicating that the H I has little rotation. Infall is also inconsistent with the line profiles, and we argue that random motion of H I clouds is the probable origin of the H I profile shapes. The properties of the H I gas agree with expectations of the cooling flow model in which cold gas is produced in situ as the hot gas radiatively cools.

Publication:

The Astrophysical Journal

Pub Date:

October 1990

DOI:

10.1086/169284

Bibcode:

1990ApJ...362..468B

Keywords: