Inamori-Magellan Areal Camera and Spectrograph

Inamori-Magellan Areal Camera and Spectrograph. It is a wide-field optical and near-infrared imaging and spectrograph instrument permanently mounted on the Magellan-Baade Telescope at the Las Campanas Observatory in Chile. Funded by a grant from the Inamori Foundation, the instrument was designed and built by a team led by the Carnegie Institution for Science to conduct large-scale surveys of the distant universe. Its unique capabilities have made it a workhorse for observational astronomy, particularly in the study of galaxy formation and cosmology.

Overview

The instrument is a versatile, multi-mode instrument that combines a large field of view with high sensitivity across optical and near-infrared wavelengths. It operates on the 6.5-meter Magellan-Baade Telescope, one of the twin telescopes at the renowned Las Campanas Observatory operated by the Carnegie Institution for Science. Its primary scientific mission involves conducting deep imaging surveys to map the distribution of galaxies and quasars across cosmic time, providing critical data for understanding large-scale structure and the expansion of the universe. The instrument's name honors the philanthropic support of the Inamori Foundation, founded by Kyocera co-founder Kazuo Inamori.

Instrument design

The core of the instrument is a cryogenically cooled focal plane array containing four CCDs, each with 2048x4096 pixels, providing a total field of view of approximately 0.5 square degrees. For spectroscopic work, it employs a set of interchangeable masks that allow for multi-object spectroscopy of hundreds of targets simultaneously across its wide field. The optical design incorporates high-throughput reflective optics and a suite of broad-band and narrow-band filters, including those similar to the Sloan Digital Sky Survey system, enabling precise photometric redshift measurements. Its operation is integrated with the Magellan Telescopes' sophisticated active optics and guidance system to ensure precise tracking and image quality.

Scientific capabilities

The instrument excels in deep, wide-field imaging surveys, capable of detecting extremely faint dwarf galaxies and high-redshift Lyman-alpha emitters in the early universe. Its multi-object spectroscopic mode is powerful for obtaining redshifts for thousands of galaxies in a single observation, crucial for projects like the Magellan Evolution of Galaxies Survey. It has been instrumental in follow-up observations for missions like the Hubble Space Telescope and the Dark Energy Survey, providing ground-based spectroscopic confirmation and complementary data. The instrument also contributes to time-domain astronomy, studying supernovae and transient events discovered by surveys like the Zwicky Transient Facility.

Development and history

The concept for the instrument was developed in the late 2000s by astronomers at the Carnegie Observatories, led by scientists including Alan Dressler. A major grant from the Inamori Foundation in 2009 provided the primary funding for construction. The instrument was built through a collaboration between the Carnegie Institution for Science, the University of Arizona Steward Observatory imaging lab, and the Australian Astronomical Observatory. After assembly and testing, it was shipped to Chile and saw first light on the Magellan-Baade Telescope in September 2012. It has been in continuous scientific operation since, with its data contributing to numerous doctoral theses and international research programs.

Key scientific results

Data from the instrument were fundamental to the Magellan Evolution of Galaxies Survey, which traced the chemical evolution and star formation histories of galaxies over billions of years. It played a key role in the HectoMAP redshift survey, mapping the detailed three-dimensional structure of the local universe to study dark matter distribution. Observations have constrained the properties of the most distant quasars known, probing the epoch of reionization. The instrument has also provided critical follow-up spectroscopy for gravitational wave events detected by LIGO, helping to identify and characterize the electromagnetic counterparts of neutron star mergers.