Gemini e-newscast #44

by xzhangIn this release:
Infrared Supernova Spectroscopy
GeMS/GSAOI Update
Users’ Committee for Gemini
GPI to Start Acceptance Testing
Gemini North Shutdown Complete
"Big" Winner of Australian Student Imaging Contest

Surprises from Infrared Supernova Spectroscopy

The supernova SN2011fe in M101 continues to develop as an exemplar of Type Ia supernovae, and it still holds surprises. The latest is the detection of unprocessed carbon from the progenitor star in a time series of near-infrared (NIR) spectra. Based on observations using GNIRS on Gemini North, Eric Hsiao (Las Campanas Observatory, Chile) and collaborators suggest that the number of SNe Ia harboring unprocessed carbon from their progenitors may be grossly underestimated based on optical studies alone. They demonstrate that the NIR carbon signature is strongest around the maximum supernova brightness, which makes it a more practical diagnostic than optical signatures, which must be captured before maximum light. A second surprise, comparing more examples, is the lack of correlation between supernova peak luminosity and velocity of ionized magnesium absorption lines.  Consequently, previous explanations for the origin of the luminosity-decline rate relationship may not be correct. More information is available in a Gemini web feature and a preprint, in advance of publication in The Astrophysical Journal.

Near-infrared spectra of SN2011fe, offset in flux for clarity and identified by time since maximum.  Gray bands mark regions of strong telluric absorption.

GeMS/GSAOI Update

Commissioning and System Verification(SV) of the Gemini Multi-Conjugate Adaptive Optics System (GeMS) with the Gemini South Adaptive Optics Imager (GSAOI) continued in late January. Six SV programs are complete, and another three have partial observations. Principal Investigators can download their data from the Gemini Science Archive. Additional detailed information about obtaining calibrations for GSAOI is posted here.

Users’ Committee for Gemini

The first report from the Users’ Committee for Gemini (UCG) is now posted , along with the Gemini response. One common theme of their recommendations is the challenge of learning what is new at Gemini. In addition to this newsletter, consider subscribing to the RSS feeds of the Science Operations Announcements or General Announcements, or find them on the right hand side of the Science Operations page. Current members of the committee and their contact information are posted. Please communicate with the members of the UCG, so they can represent the needs of all users.

GPI to Start Acceptance Testing

The Gemini Planet Imager (GPI) has concluded its characterization stage at the Laboratory for Adaptive Optics at the University of California Santa Cruz. The team spanning eight US and Canadian institutions will begin the acceptance test stage on February 19, which will last about three months. This will be followed by a pre-delivery review and then plans for shipping to Gemini South. Instrument characterization has already produced some great lab results (see following figure). 

This image shows a still from data slices of a single 60-second exposure using an incandescent light source through the GPI telescope simulator and using atmospheric turbulence phase plates. The known planetary system of HR8799 has been superposed on the image, showing the direct detection of the planets without further processing. (The known planets in HR8799 are labeled a-e.) Useful low-resolution spectra could be extracted from even such a short exposure.

Gemini North Shutdown Complete

The Gemini North telescope completed a successful maintenance shutdown that began on January 22, returning to science on the night of February 2. During the shutdown many key systems underwent maintenance and/or upgrades, with the most significant work focusing on the acquisition and guiding (A&G) system and the installation of sensors to help measure vibrations and further improve high-resolution adaptive optics imaging. Safety mechanisms were added to the A&G and to the Gemini Multi-Object Spectrograph, to prevent known mechanical failure modes. We were not able to complete a planned recoating of the primary mirror, after severe freezing on the summit ruptured a coolant water line inside the coating chamber. This coating work will be postponed until later in 2013.

Engineers working on the acquisition and guiding unit.

"Big" Winner of Australian Student Imaging Contest

Australian high school senior Ryan Soares won the most recent Australian Gemini Schools Imaging Contest with a large mosaic image of NGC 7232 and its surroundings obtained from Gemini South. The contest, sponsored by the Australian Gemini Office, and entering its 5th year, asks students to suggest targets to be imaged by Gemini as part of the Australian time allocation. Learn more and see additional photos at www.gemini.edu/node/11955.

The galaxies NGC 7232B (at left), NGC7233 (top right), and NGC 7232 (right of center) are featured in the latest winner of the Australian/Gemini Student Imaging Contest. The data were obtained in 2012 at the Gemini South telescope in Chile using the Gemini Multi-Object Spectrograph (GMOS) and the color composite image produced by Travis Rector, University of Alaska Anchorage.