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

Sullivan, Peter; Simcoe, Robert A.

doi:10.1086/668849

Cited by 36 publications

(36 citation statements)

References 18 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…Sullivan & Simcoe 2012), so improved S/N could potentially be achieved by observing from space. Above the Earth's atmosphere, the background is dominated by zodiacal light which can be minimized by observing a target at high ecliptic latitude.…”

Section: Discussionmentioning

confidence: 99%

Quasar ionization front Lyα emission in an inhomogeneous intergalactic medium

Davies

Furlanetto

McQuinn

2016

Mon. Not. R. Astron. Soc.

View full text Add to dashboard Cite

The conditions within the ionization front of a quasar during reionization (T ∼ 30, 000 K, neutral hydrogen fraction x H I ∼ 0.5) are ideal for producing Lyα emission via collisional excitation of hydrogen atoms. Observations of this emission, which could subtend > ∼ 10 arcmin 2 on the sky, would definitively demonstrate the presence of a neutral intergalactic medium at the observed epoch, placing valuable constraints on the progress of reionization. We find that the expected Lyα surface brightness is significantly weaker than previously determined and may be impossible to observe with current and near-future instruments. Past work calculated the Lyα emission from a quasar ionization front in a homogeneous medium with a clumping factor approximation to account for inhomogeneities. We find using 1D radiative transfer calculations that this approximation overestimates the emission by a factor of > ∼ 3. Our calculations model the propagation of ionizing photons and compute the Lyα emission from quasar ionization fronts on sightlines from a hydrodynamic cosmological simulation at z = 7.1. To better understand the physical properties of the emission, we also develop an analytic model that accurately describes the results of the full radiative transfer calculation.

show abstract

Section: Discussionmentioning

confidence: 99%

Quasar ionization front Lyα emission in an inhomogeneous intergalactic medium

Davies

Furlanetto

McQuinn

2016

Mon. Not. R. Astron. Soc.

View full text Add to dashboard Cite

show abstract

“…3 Because IR spectrographs on 6-10 meter telescopes suffer from read noise, the scale-up to GMT's larger aperture should produce large gains in sensitivity even when seeing limited. Assuming identical sensor noise, this requires that the plate scale in arcseconds per pixel is matched between FIRE and SuperFIRE so that increase in aperture is not offset by diffusion of photon flux.…”

Section: Derived Instrument Requirementsmentioning

confidence: 99%

A concept for seeing-limited near-IR spectroscopy on the Giant Magellan Telescope

et al. 2016

Self Cite

View full text Add to dashboard Cite

We present a simple seeing-limited IR spectrometer design for the Giant Magellan Telescope, with continuous R = 6000 coverage from 0.87-2.50 microns for a 0.7 slit. The instrument's design is based on an asymmetric white pupil echelle layout, with dichroics splitting the optical train into yJ, H, and K channels after the pupil transfer mirror. A separate low-dispersion mode offers single-object R ∼ 850 spectra which also cover the full NIR bandpass in each exposure. Catalog gratings and H2RG detectors are used to minimize cost, and only two cryogenic rotary mechanisms are employed, reducing mechanical complexity. The instrument dewar occupies an envelope of 1.8×1.5×1.2 meters, satisfying mass and volume requirements for GMT with comfortable margin. We estimate the system throughput at ∼ 35% including losses from the atmosphere, telescope, and instrument (i.e. all coatings, gratings, and sensors). This optical efficiency is comparable to the FIRE spectrograph on Magellan, and we have specified and designed fast cameras so the GMT instrument will have an almost identical pixel scale as FIRE. On the 6.5 meter Magellan telescopes, FIRE is read-noise limited in the y and J bands, similar to other existing near-IR spectrometers and also to JWST/NIRSPEC. GMT's twelve-fold increase in collecting area will therefore offer gains in signal-to-noise per exposure that exceed those of moderate resolution optical instruments, which are already sky-noise limited on today's telescopes. Such an instrument would allow GMT to pursue key early science programs on the Epoch of Reionization, galaxy formation, transient astronomy, and obscured star formation environments prior to commissioning of its adaptive optics system. This design study demonstrates the feasibility of developing relatively affordable spectrometers at the ELT scale, in response to the pressures of joint funding for these telescopes and their associated instrument suites.

show abstract

“…In particular, all spectrographs unavoidably scatter light, resulting in a point spread function with strongly Lorentzian wings, 23 Thus, the dark regions in between the OH lines is contaminated by the scattered OH lines, and this may even dominate the interline regions. 17,25 High dispersion masking of the cores of the lines does not remove this scattered light. In order to truly exploit the dark regions between the OH lines other solutions must be found.…”

Section: Filtering Atmospheric Emission Linesmentioning

confidence: 99%

Speciality optical fibres for astronomy

Ellis

Bland-Hawthorn

2015

SPIE Proceedings

View full text Add to dashboard Cite

Astrophotonics is a rapidly developing area of research which applies photonic technology to astronomical instrumentation. Such technology has the capability of significantly improving the sensitivity, calibration and stability of astronomical instruments, or indeed providing novel capabilities which are not possible using classical optics. We review the development and application of speciality fibres for astronomy, including multi-mode to single-mode converters, notch filters and frequency combs.In particular we focus on our development of instruments designed to filter atmospheric emission lines to enable much deeper spectroscopic observations in the near-infrared. These instruments employ two novel photonic technologies. First, we have developed complex aperiodic fibre Bragg gratings which filter over 100 irregularly spaced wavelengths in a single device, covering a bandwidth of over 200 nm. However, astronomical instruments require highly multi-mode fibres to enable sufficient coupling into the fibre, since atmospheric turbulence heavily distorts the wavefront. But photonic technologies such as fibre Bragg gratings, require single mode fibres. This problem is solved by the photonic lantern, which enables efficient coupling from a multi-mode fibre to an array of single-mode fibres and vice versa.We present the results of laboratory tests of these technologies and of on-sky experiments made using the first instruments to deploy these technologies on a telescope. These tests show that the fibre Bragg gratings suppress the night sky background by a factor of 9. Current instruments are limited by thermal and detector emission. Planned instruments should improved the background suppression even further, by optimising the design of the spectrograph for the properties of the photonic components.Finally we review ongoing research in astrophotonics, including multi-moded multicore fibre Bragg gratings, which enable multiple gratings to be written into the same device simultaneously, femtosecond direct-write photonic lanterns and Bragg gratings, and complex notch filters and frequency combs using microring resonators, and plans for future astrophotonic instrumentation.

show abstract

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

Cited by 36 publications

References 18 publications

Quasar ionization front Lyα emission in an inhomogeneous intergalactic medium

Quasar ionization front Lyα emission in an inhomogeneous intergalactic medium

A concept for seeing-limited near-IR spectroscopy on the Giant Magellan Telescope

Speciality optical fibres for astronomy

Contact Info

Product

Resources

About