First demonstration of OH suppression in a high efficiency near-infrared spectrograph

Abstract

Ground-based near-infrared astronomy is severely hampered by the forest of atmospheric emission lines resulting from the rovibrational decay of OH molecules in the upper atmosphere. The extreme brightness of these lines, as well as their spatial and temporal variability, makes accurate sky subtraction difficult. Selectively filtering these lines with OH suppression instruments has been a long standing goal for near-infrared spectroscopy. We have shown previously the efficacy of fibre Bragg gratings combined with photonic lanterns for achieving OH suppression. Here we report on PRAXIS, a unique near-infrared spectrograph that is optimised for OH suppression with fibre Bragg gratings. We show for the first time that OH suppression (of any kind) is possible with high overall throughput (18 per cent end-to-end), and provide examples of the relative benefits of OH suppression.

Accepted for publication in MNRAS

References in corpus (7)

• The Photonic Lantern
• A method to remove residual OH emission from near infrared spectra
• GNOSIS: the first instrument to use fibre Bragg gratings for OH suppression
• The case for OH suppression at near-infrared wavelengths
• The Narrow Line Region of the Seyfert 2 galaxy Mrk 78. An infrared view
• PRAXIS: a low background NIR spectrograph for fibre Bragg grating OH suppression
• Photonic lantern behaviour and implications for instrument design

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• Temperature-compensating package for OH line filters for astronomy: II. manufacture, assembly, and performance study
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