Christopher Q. Trinh

SOFIA-USRA

We describe the design of the Field-Imaging Far-Infrared Line Spectrometer (FIFI-LS), operated as a Facility-Class instrument on the Stratospheric Observatory for Infrared Astronomy (SOFIA). FIFI-LS is an imaging spectrometer for medium resolution spectroscopy. Since being commissioned in 2014, it has performed over 50 SOFIA commissioning and scien...

Observing on the Stratospheric Observatory for Infrared Astronomy (SOFIA) requires a strategy that takes the specific circumstances of an airborne platform into account. Observations of a source cannot be extended or shortened on the spot due to flight path constraints. Still, no exact prediction of the time on source is available since there are a...

(Abridged) We analyse the near-infrared interline sky background, OH and O2 emission in 19 hours of H band observations with the GNOSIS OH suppression unit and the IRIS2 spectrograph at the 3.9-m AAT. The observations cover a range of sky positions with varying lunar conditions throughout the night. We measure the interline background at 1.520 micr...

GNOSIS is a prototype astrophotonic instrument that utilizes OH suppression fibres consisting of fibre Bragg gratings and photonic lanterns to suppress the 103 brightest atmospheric emission doublets between 1.47-1.7 microns. GNOSIS was commissioned at the 3.9-meter Anglo-Australian Telescope with the IRIS2 spectrograph to demonstrate the potential...

We have devised a method to select galaxies that are isolated in their dark matter halo (N = 1 systems) and galaxies that reside in a group of exactly two (N = 2 systems). Our N = 2 systems are widely separated (up to ∼200 h−1 kpc), where close galaxy–galaxy interactions are not dominant. We apply our selection criteria to two volume-limited sample...

The sky background is over 1000 times brighter in the near-infrared (NIR) than in the visible placing severe limitations on our ability to study the redshifted light from the distant objects formed in the early Universe from the ground. It is well-known that 98% of the NIR background comes from the forest of bright and highly variable emission line...

We present the first scientific results from the Sydney-AAO Multi-Object IFS (SAMI) at the Anglo-Australian Telescope. This unique instrument deploys 13 fused fibre bundles (hexabundles) across a one-degree field of view allowing simultaneous spatially-resolved spectroscopy of 13 galaxies. During the first SAMI commissioning run, targeting a single...

The background noise between 1 and 1.8 μm in ground-based instruments is dominated by atmospheric emission from hydroxyl molecules. We have built and commissioned a new instrument, the Gemini Near-infrared OH Suppression Integral Field Unit (IFU) System (GNOSIS), which suppresses 103 OH doublets between 1.47 and 1.7 μm by a factor of ≈1000 with a r...

GNOSIS has provided the first on-telescope demonstration of a concept to utilize complex aperioidc fiber Bragg gratings to suppress the 103 brightest atmospheric hydroxyl emission doublets between 1.47-1.7 μm. The unit is designed to be used at the 3.9-meter Anglo-Australian Telescope (AAT) feeding the IRIS2 spectrograph. Unlike previous atmospheri...

Ground based near-infrared observations have long been plagued by poor sensitivity when compared to visible observations as a result of the bright narrow line emission from atmospheric OH molecules. The GNOSIS instrument recently commissioned at the Australian Astronomical Observatory uses Photonic Lanterns in combination with individually printed...

We discuss the development of multi-core fiber Bragg gratings (FBGs) to be applied to astrophotonics, more specifically to near-infrared spectroscopy for ground-based instruments. The multi-core FBGs require over 100 notches to reject the OH lines in a broad wavelength range (160 nm). The number of cores of the fiber should correspond to the mode n...

We demonstrate a novel technology that combines the power of the multi-object spectrograph with the spatial multiplex advantage of an integral field spectrograph (IFS). The Sydney-AAO Multi-object IFS (SAMI) is a prototype wide-field system at the Anglo-Australian Telescope (AAT) that allows 13 imaging fibre bundles ("hexabundles") to be deployed o...

A long-standing and profound problem in astronomy is the difficulty in obtaining deep near-infrared observations due to the extreme brightness and variability of the night sky at these wavelengths. A solution to this problem is crucial if we are to obtain the deepest possible observations of the early Universe, as redshifted starlight from distant...

We use a volume-limited spectroscopic sample of isolated galaxies in the Sloan Digital Sky Survey to investigate the frequency and radial distribution of luminous (Mr –18.3) satellites like the Large Magellanic Cloud (LMC) around ~L * Milky Way (MW) analogs and compare our results object-by-object to ΛCDM predictions based on abundance matching in...

Astronomical near-infrared spectroscopy is made difficult by the extremely bright and variable night sky background. The night sky surface brightness is more than a thousand times brighter at 1.6μm than at 0.4μm. Furthermore the brightness of the sky changes by factors of -10% on time-scales of minutes. Background subtraction is therefore frustrate...

We use a volume-limited spectroscopic sample of isolated galaxies in the Sloan Digital Sky Survey (SDSS) to investigate the frequency and radial distribution of luminous (M_r <~ -18.3) satellites like the Large Magellanic Cloud (LMC) around ~L* Milky Way analogs and compare our results object-by-object to LCDM predictions based on abundance matchin...

Substructure in LCDM provides a number of interesting puzzles. While the missing satellites problem is well-studied, there are suggestions of an opposite problem on the bright end. Subhalos large enough to host luminous satellites are uncommon, so we investigate whether the existence of the Large Magellanic Cloud (LMC) orbiting the Galaxy is a chal...

Modern redshift surveys enable the identification of large samples of galaxies in pairs, taken from many different environments. Meanwhile, cosmological simulations allow a detailed understanding of the statistical properties of the selected pair samples. Using these tools in tandem leads to a quantitative understanding of the effects of galaxy-gal...

Star formation quenching is in part responsible for the build-up of the red sequence of galaxies. Thus, quenching mechanisms are one of the central problems in galaxy evolution. However, quenching time-scales are largely unconstrained. Using mock galaxy redshift surveys created using hybrid N-body/semi-analytic substructure simulations, we have dev...

We examine the inner structure of the polar ring galaxies UGC 7576, NGC 2685, and NGC 3718 in U, B, V, and R with images from the WIYN 3.5 meter telescope. Residual images reveal the presence of a luminous, warped disk-like structure in the central host of UGC 7576 and NGC 2685, which is consistent with an S0 morphology. Color maps indicate a B-R c...

We use the technique known as optical pumping to measure the nuclear spin of Rb87 and Rb85 as well as the strength of the magnetic fleld of the Earth. We use plots of the resonance frequency versus the current or magnetic fleld from a Helmholtz coil for each isotope, the Breit-Rabi equation, and the expression for the magnetic fleld strength at the...