On-sky tests of sky-subtraction methods for fiber-fed spectrographs

Rodrigues, M.; Cirasuolo, M.; Hammer, F.; Royer, F.; Evans, Christopher J.; Puech, M.; Flores, H.; Guinouard, Isabelle; Causi, G. Li; Disseau, K.; Yang, Yuanheng

doi:10.1117/12.924878

Cited by 8 publications

(3 citation statements)

References 9 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…Additionally, the exact multiplex in HMM-NIR is still to be confirmed. This depends on whether or not the fibres can be deployed independently or have to be paired at the hardware level so as to carry out cross-beam switching 12 to improve the sky subtraction accuracy. In the latter case the effective multiplex will reduce to 70.…”

Section: Updated Top-level Requirementsmentioning

confidence: 99%

MOSAIC: the high-multiplex and multi-IFU spectrograph for the ELT

Sánchéz-Janssen¹,

Hammer²,

Morris³

et al. 2020

Preprint

Self Cite

View full text Add to dashboard Cite

MOSAIC is the planned multi-object spectrograph for the 39m Extremely Large Telescope (ELT). Conceived as a multi-purpose instrument, it offers both high multiplex and multi-IFU capabilities at a range of intermediate to high spectral resolving powers in the visible and the near-infrared. MOSAIC will enable unique spectroscopic surveys of the faintest sources, from the oldest stars in the Galaxy and beyond to the first populations of galaxies that completed the reionisation of the Universe-while simultaneously opening up a wide discovery space. In this contribution we present the status of the instrument ahead of Phase B, showcasing the key science cases as well as introducing the updated set of top level requirements and the adopted architecture. The high readiness level will allow MOSAIC to soon enter the construction phase, with the goal to provide the ELT community with a world-class MOS capability as soon as possible after the telescope first light.

show abstract

Section: Updated Top-level Requirementsmentioning

confidence: 99%

MOSAIC: the high-multiplex and multi-IFU spectrograph for the ELT

Sánchéz-Janssen¹,

Hammer²,

Morris³

et al. 2020

Preprint

Self Cite

View full text Add to dashboard Cite

show abstract

“…28) and on spatial scales of arcminutes. 29 It is therefore necessary to obtain sky spectra at the same time as the target spectra.…”

Section: Considerations For Sky Subtractionmentioning

confidence: 99%

The science calibration challenges of next generation highly multiplexed optical spectroscopy: the case of the Maunakea Spectroscopic Explorer

McConnachie¹,

Flagey²,

Hall

et al. 2018

Observatory Operations: Strategies, Processes, and Systems VII

View full text Add to dashboard Cite

MSE is an 11.25m telescope with a 1.5 sq.deg. field of view. It can simultaneously obtain 3249 spectra at R = 3000 from 360−1800nm, and 1083 spectra at R = 40000 in the optical. The large field of view, large number of targets, as well as the use of more than 4000 optical fibres to transport the light from the focal plane to the spectrographs, means that precise and accurate science calibration is difficult but essential to obtaining the science goals. As a large aperture telescope focusing on the faint Universe, precision sky subtraction and spectrophotometry are especially important. Here, we discuss the science calibration requirements, and the adopted calibration strategy, including operational features and hardware, that will enable the successful scientific exploitation of the vast MSE dataset.

show abstract

“…For the long-slit spectrographs, the sky can be derived by interpolating adjacent blank sky regions and subtracted from the target (Soto et al 2016). On the other hand, this method does not work well for the multi-fiber spectrographs, but considerable progress has been made in the last three decades to address sky subtractions, such as beam-switching (Barden et al 1993;Puech et al 2014;Rodrigues et al 2012), nod-and-shuffle (Glazebrook & Bland-Hawthorn 2001;Sharp & Parkinson 2010), and principal component analysis (PCA, Wild & Hewett 2005;Soto et al 2016).…”

Section: Introductionmentioning

confidence: 99%

LAMOST medium-resolution spectral survey of Galactic nebulae (LAMOST-MRS-N): subtraction of geocoronal Hα emission

Zhang

et al. 2021

Res. Astron. Astrophys.

View full text Add to dashboard Cite

We introduce a method of subtracting geocoronal Hα emissions from the spectra of LAMOST medium-resolution spectral survey of Galactic nebulae (LAMOST-MRS-N). The flux ratios of the Hα sky line to the adjacent OH λ6554 single line do not show a pattern or gradient distribution in a plate. More interestingly, the ratio is well correlated to solar altitude, which is the angle of the Sun relative to the Earthʼs horizon. It is found that the ratio decreases from 0.8 to 0.2 with the decreasing solar altitude from –17 to –73 degree. Based on this relation, which is described by a linear function, we can construct the Hα sky component and subtract it from the science spectrum. This method has been applied to the LAMOST-MRS-N data, and the contamination level of the Hα sky to nebula is reduced from 40% to less than 10%. The new generated spectra will significantly improve the accuracy of the classifications and the measurements of physical parameters of Galactic nebulae.

show abstract

On-sky tests of sky-subtraction methods for fiber-fed spectrographs

Cited by 8 publications

References 9 publications

MOSAIC: the high-multiplex and multi-IFU spectrograph for the ELT

MOSAIC: the high-multiplex and multi-IFU spectrograph for the ELT

The science calibration challenges of next generation highly multiplexed optical spectroscopy: the case of the Maunakea Spectroscopic Explorer

LAMOST medium-resolution spectral survey of Galactic nebulae (LAMOST-MRS-N): subtraction of geocoronal Hα emission

Contact Info

Product

Resources

About