Gemini e-Newscast #26 -- May 17, 2010

by jpollard

An extremely massive cannibalistic galaxy

The discovery of a gravitational lens in the central galaxy of cluster Abell 3827 allows for the measurement of the galaxy mass, and it may reveal the most massive galaxy known in the local universe. The central galaxy has an asymmetric halo, and it shows the remains of at least four other incompletely merged galaxies. R. Carrasco (Gemini Observatory) and colleagues used imaging and spectroscopy from GMOS on Gemini South, combined with modeling of the lenses, to find a galactic mass of about 3 x 1013 MSun, which is an order of magnitude larger than the X-ray-indicated mass. Complete results appear in the Astrophysical Journal Letters (2010 715 L160) and are featured at

More dust from supernovae, but not enough

Luminous infrared galaxies (LIRGs) at high redshift contain great amounts of dust, but a complete account of the origin of the dust so quickly in the history of the universe remains lacking. Some dust is produced in supernovae, as local observations demonstrate. J. E. Andrews (Louisiana State University) and colleagues find evidence for early dust formation in the type IIP SN 2007od, based on both the H alpha profile and the mid-IR excess, but the quantity (up to around 4 x 10-4 MSun) means that supernovae are not likely the primary source of dust in LIRGs, even allowing for dust formation in circumstellar interactions as well as in the ejecta. These results are based on observations with the GMOS instruments on Gemini North and South, as well as HST, Spitzer, and the SMARTS 1.3m telescope. They are published in the Astrophysical Journal (2010 715 541).

GNIRS update

GNIRS is now cold in the Hilo lab for a third round of tests. The science detector is in place and at operating temperature. Instrument characterization is a key aspect of the current work. We expect to have GNIRS on Mauna Kea in July to start on-sky commissioning.

Welcome Andy Adamson

We are pleased to welcome Andy Adamson as he starts work today as the Associate Director of Science Operations. Andy leaves his post as Associate Director of the UK Infrared Telescope, having just exceeded 11 years at the Joint Astronomy Centre. He had previously spent over ten years at the University of Central Lancashire as a postdoctoral researcher and lecturer. Andy's primary research interest is interstellar dust and its relationship to interstellar molecules, which he studies using infrared spectroscopy and polarimetry. We also take this opportunity to thank Dennis Crabtree for his contributionsover the past three years. Dennis has returned to the Herzberg Institute of Astrophysics in Canada.