Ian Glass

Ian Glass was born in Dublin and educated at Trinity College Dublin and MIT. His (Physics) PhD thesis was in x-ray astronomy but following a Post-Doc with Neugebauer at Caltech he switched over to infrared. In 1970-75 he worked at the Royal Greenwich Observatory. During the middle three years of this period he was assigned to the Royal Observatory/SAAO in Cape Town. He joined SAAO in 1975  but was forced to retire in 1999, remaining as a contract employee until the end of 2005. Since then he has been an unpaid “Associate Research Astronomer”.

He has designed and constructed numerous infrared instruments as well as contributing to updating the older Sutherland telescopes, the field acquisition cameras and the Unit Spectrograph. The SAAO became a centre for southern infrared studies as a result of these instruments being available.

Observationally, he started by setting up a network of southern infrared standards. Many pioneering studies were done of a large variety of objects such as active galaxies, Magellanic Cloud stars, M,C and S stars, RCB variables, T-Tauris, Miras, old novae, symbiotic stars, Be stars and  x-ray source counterparts. (These projects were often carried out with collaborators both inside and outside SAAO.)

Highlights of his career included a long-term study of active galaxies, one of which (Fairall 9) clearly showed delayed emission from dust heated by the ultraviolet radiation from the black hole region and provided convincing evidence for the “dust reverberation model”. Essentially all active nuclei were shown to vary in the infrared.

The obscured x-ray source Cir X-1 was observed to flare in a cyclic manner associated with its binary period.

With Lloyd Evans, who located the first sample of Mira variables in the LMC, he showed that these stars obey a clear period-luminosity relation in the infrared. This work was refined and then extended to various other samples such as the Baade’s Window fields near the Galactic Centre, producing an independent distance estimate.

Work with the ISOGAL group using the ISO satellite showed that not only Miras show mass-loss but all late-type M stars do so as well and further are all variable. This led to some papers on the P-L and mass-loss systematics of Semi-Regular variables.

A number of projects concerned identification of IRAS infrared sources near the Galactic Centre. One of these was the “Quintuplet” cluster (simultaneously found by Okuda et al). One large project was the mapping of the Galactic Centre region in the pre-array days, showing up extinction patterns that correlated with the intervening molecular clouds. A later large project in the inner part of the Bulge identified large numbers of Mira-like variables.

Glass’s current interest is in the history of astronomy. His latest book is about a pioneering French astronomer: “Nicolas-Louis de La Caille, Astronomer and Geodesist”, who visited the Cape in 1751-3.