Suppression of the near-infrared OH night-sky lines with fibre Bragg gratings - first results

Ellis, S. C.; Bland-Hawthorn, Joss; Lawrence, Jon; Horton, Anthony; Trinh, Christopher; Leon-Saval, Sergio G.; Shortridge, Keith; Bryant, Julia J.; Case, Scott W.; Colless, Matthew; Couch, W.; Freeman, K. C.; Gers, Luke; Glazebrook, Karl; Haynes, Roger; Lee, S.; Löhmannsröben, H.‐G.; O’Byrne, John W.; Miziarski, Stan; Roth, Martin; Schmidt, B. P.; Tinney, C. G.; Zheng, Rong

doi:10.1111/j.1365-2966.2012.21602.x

Cited by 45 publications

(31 citation statements)

References 32 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…In contrast to our results, these lines were predicted to be unresolved by the R2000 list. Similar discrepancies for a few Q lines were also reported by Ellis et al (2012).…”

Section: Oh Wavelengths and Fluxessupporting

confidence: 88%

A GIANO-TNG high-resolution infrared spectrum of the airglow emission

Oliva

Origlia

Maiolino

et al. 2013

A&A

View full text Add to dashboard Cite

Aims. A flux-calibrated high-resolution spectrum of the airglow emission is a practical λ-calibration reference for astronomical spectral observations. It is also useful for constraining the molecular parameters of the OH molecule and the physical conditions in the upper mesosphere. Methods. We used the data collected during the first technical commissioning of the GIANO spectrograph at the Telescopio Nazionale Galileo (TNG). The high-resolution (R 50 000) spectrum simultaneously covers the 0.95-2.4 μm wavelength range. Relative flux calibration is achieved by the simultaneous observation of a spectrophotometric standard star. Results. We derived a list of improved positions and intensities of OH infrared lines. The list includes Λ-split doublets, many of which are spectrally resolved. Compared with previous works, the new results correct errors in the wavelengths of the Q-branch transitions. The relative fluxes of OH lines from different vibrational bands show remarkable deviations from theoretical predictions: the Δv = 3, 4 lines are a factor of 2 and 4 brighter than expected. We also found evidence of a significant fraction (1-4%) of OH molecules with a non-thermal population of high-J levels. Finally, we list wavelengths and fluxes of 153 lines not attributable to OH. Most of these can be associated with O 2 , while 37 lines in the H band are not identified. The O 2 and unidentified lines in the H band account for 5% of the total airglow flux in this band.

show abstract

“…In contrast to our results, these lines were predicted to be unresolved by the R2000 list. Similar discrepancies for a few Q lines were also reported by Ellis et al (2012).…”

Section: Oh Wavelengths and Fluxessupporting

confidence: 88%

A GIANO-TNG high-resolution infrared spectrum of the airglow emission

Oliva

Origlia

Maiolino

et al. 2013

A&A

View full text Add to dashboard Cite

show abstract

“…This background would slightly weaken the case for OH-suppressed instruments (e.g., Ellis et al 2012), but it would also lessen the technical requirements for OH-suppressed instruments to achieve background-limited performance in the J from ∼30-35 dB narrowband attenuation to ∼20 dB. These arguments are particularly germane for studies of the Lyman alpha transition in high-redshift objects since it is observable in the dark portions of Y and J bands throughout the epoch of cosmic reionization.…”

Section: Implications For Telescope Allocation and Instrument Designmentioning

confidence: 99%

A Calibrated Measurement of the Near-IR Continuum Sky Brightness Using Magellan/FIRE

Sullivan

Simcoe

2012

Publications of the Astronomical Society of the Pacific

View full text Add to dashboard Cite

ABSTRACT. We characterize the near-IR sky background from 308 observations with the Folded-port InfraRed Echellette (FIRE) spectrograph at Magellan. A subset of 105 observations selected to minimize lunar and thermal effects gives a continuous, median spectrum from 0.83 to 2.5 μm, which we present in Table 2(see the online edition of the PASP for this table). The data are used to characterize the broadband continuum emission between atmospheric OH features and correlate its properties with observing conditions such as lunar angle and time of night. We find that the Moon contributes significantly to the inter-line continuum in Y and J bands, whereas the observed H-band continuum is dominated by the blended Lorentzian wings of multiple OH line profiles, even at R ¼ 6000. Lunar effects may be mitigated in Y and J through careful scheduling of observations, but the most ambitious near-IR programs will benefit from allocation during dark observing time if those observations are not limited by read noise. In Y and J, our measured continuum exceeds space-based average estimates of the zodiacal light, but it is not readily identified with known terrestrial foregrounds. If further measurements confirm such a fundamental background, it would impact requirements for OH-suppressed instruments operating in this regime.

show abstract

“…Results from GNOSIS, a prototype FBG OH suppression system which used the existing IRIS2 spectrograph on the Anglo-Australian Telescope, illustrate the potential impact of dark current. Figure 1 shows the background levels observed by GNOSIS, as reported by Ellis et al 5 The PACE HAWAII-1 HgCdTe detector used in IRIS2 has a measured dark current of 0.015 e − s −1 pixel −1 however even this relatively low value is sufficient to dominate the observed background for wavelengths less than 1.67 µm. There are two main factors effecting the impact of dark current, detector selection and spectral format.…”

Section: Dark Currentmentioning

confidence: 67%

“…4 The effectiveness of this background suppression clearly has the potential to significantly increase the sensitivity of ground based near infrared spectroscopy however in order to fulfil this potential the spectrographs must have very low instrumental backgrounds so that they remain sky background noise limited. Simulations as well as real world experience gained during the commissioning of the GNOSIS system with the IRIS2 spectrograph on the AAT 2,5 suggest that existing spectrographs, optimised for much higher sky background levels, will be unable to fully exploit the benefits FBG OH suppression. A purpose built, specialised spectrograph is required and for that reason we plan to built PRAXIS.…”

Section: Introductionmentioning

confidence: 99%

PRAXIS: a low background NIR spectrograph for fibre Bragg grating OH suppression

et al. 2012

View full text Add to dashboard Cite

Fibre Bragg grating (FBG) OH suppression is capable of greatly reducing the bright sky background seen by near infrared spectrographs. By filtering out the airglow emission lines at high resolution before the light enters the spectrograph this technique prevents scattering from the emission lines into interline regions, thereby reducing the background at all wavelengths. In order to take full advantage of this sky background reduction the spectrograph must have very low instrumental backgrounds so that it remains sky noise limited. Both simulations and real world experience with the prototype GNOSIS system show that existing spectrographs, designed for higher sky background levels, will be unable to fully exploit the sky background reduction. We therefore propose PRAXIS, a spectrograph optimised specifically for this purpose.The PRAXIS concept is a fibre fed, fully cryogenic, fixed format spectrograph for the J and H-bands. Dark current will be minimised by using the best of the latest generation of NIR detectors while thermal backgrounds will be reduced by the use of a cryogenic fibre slit. Optimised spectral formats and the use of high throughput volume phase holographic gratings will further enhance sensitivity. Our proposal is for a modular system, incorporating exchangeable fore-optics units, integral field units and OH suppression units, to allow PRAXIS to operate as a visitor instrument on any large telescope and enable new developments in FBG OH suppression to be incorporated as they become available. As a high performance fibre fed spectrograph PRAXIS could also serve as a testbed for other astrophotonic technologies.

show abstract

Suppression of the near-infrared OH night-sky lines with fibre Bragg gratings - first results

Cited by 45 publications

References 32 publications

A GIANO-TNG high-resolution infrared spectrum of the airglow emission

A GIANO-TNG high-resolution infrared spectrum of the airglow emission

A Calibrated Measurement of the Near-IR Continuum Sky Brightness Using Magellan/FIRE

PRAXIS: a low background NIR spectrograph for fibre Bragg grating OH suppression

Contact Info

Product

Resources

About