Professor Ray Sharples' Outputs (189)

Correcting Turbulence-induced Errors in Fiber Positioning for the Dark Energy Spectroscopic Instrument (2024)
Journal Article
Schlafly, E. F., Guy, J., Honscheid, K., Kent, S., Koposov, S. E., Aguilar, J., Ahlen, S., Bailey, S., Brooks, D., Claybaugh, T., Dawson, K., Doel, P., Fanning, K., Finkbeiner, D. P., Font-Ribera, A., Forero-Romero, J. E., Gontcho A Gontcho, S., Gutierrez, G., Kirkby, D., Kisner, T., …DESI. (2024). Correcting Turbulence-induced Errors in Fiber Positioning for the Dark Energy Spectroscopic Instrument. Astronomical Journal, 168(6), Article 263. https://doi.org/10.3847/1538-3881/ad7e12

Highly multiplexed, robotic, fiber-fed spectroscopic surveys are observing tens of millions of stars and galaxies.
For many systems, accurate positioning relies on imaging the fibers in the focal plane and feeding that information
back to the robot... Read More about Correcting Turbulence-induced Errors in Fiber Positioning for the Dark Energy Spectroscopic Instrument.

Overview of the Fiber System for the Dark Energy Spectroscopic Instrument (2024)
Journal Article
Poppett, C., Tyas, L., Aguilar, J., Bebek, C., Bramall, D., Claybaugh, T., Edelstein, J., Fagrelius, P., Heetderks, H., Jelinsky, P., Jelinsky, S., Lafever, R., Lambert, A., Lampton, M., Levi, M. E., Martini, P., Rockosi, C., Schmoll, J., Sharples, R. M., Sirk, M., …Zhou, R. (2024). Overview of the Fiber System for the Dark Energy Spectroscopic Instrument. Astronomical Journal, 168(6), Article 245. https://doi.org/10.3847/1538-3881/ad76a4

The Dark Energy Spectroscopic Instrument (DESI) is a revolutionary instrument designed for precise measurements of cosmic distances and the investigation of dark energy. DESI utilizes 5000 optical fibers to simultaneously measure the spectra of dista... Read More about Overview of the Fiber System for the Dark Energy Spectroscopic Instrument.

A field programmable gate array based Langmuir probe system for measurement of plasma parameters at 500 kHz in a high-power impulse magnetron sputtering plasma. (2024)
Journal Article
Hickling, C. J., Hall, S., Harrison, J. R., Sharples, R., & Bradley, J. W. (2024). A field programmable gate array based Langmuir probe system for measurement of plasma parameters at 500 kHz in a high-power impulse magnetron sputtering plasma. Review of Scientific Instruments, 95(3), Article 033503. https://doi.org/10.1063/5.0174458

By utilizing Field Programmable Gate Arrays in a configuration similar to that of the Mirror Langmuir Probe, it is possible to bias a single probe at three precise voltages in sequence. These voltages can be dynamically adjusted in real-time based on... Read More about A field programmable gate array based Langmuir probe system for measurement of plasma parameters at 500 kHz in a high-power impulse magnetron sputtering plasma..

GTC Follow-up Observations of Very Metal-poor Star Candidates from DESI (2023)
Journal Article
Allende Prieto, C., Aguado, D. S., González Hernández, J. I., Rebolo, R., Najita, J., Manser, C. J., …Zou, H. (2023). GTC Follow-up Observations of Very Metal-poor Star Candidates from DESI. Astrophysical Journal, 957(2), Article 76. https://doi.org/10.3847/1538-4357/acfa96

The observations from the Dark Energy Spectroscopic Instrument (DESI) will significantly increase the numbers of known extremely metal-poor stars by a factor of ∼10, improving the sample statistics to study the early chemical evolution of the Milky W... Read More about GTC Follow-up Observations of Very Metal-poor Star Candidates from DESI.

KURVS: the outer rotation curve shapes and dark matter fractions of z ∼ 1.5 star-forming galaxies (2023)
Journal Article
Puglisi, A., Dudzevičiūtė, U., Swinbank, M., Gillman, S., Tiley, A. L., Bower, R. G., …Sharples, R. M. (2023). KURVS: the outer rotation curve shapes and dark matter fractions of z ∼ 1.5 star-forming galaxies. Monthly Notices of the Royal Astronomical Society, 524(2), 2814-2835. https://doi.org/10.1093/mnras/stad1966

We present first results from the KMOS Ultra-deep Rotation Velocity Survey (KURVS), aimed at studying the outer rotation curves shape and dark matter content of 22 star-forming galaxies at z ∼1.5. These galaxies represent ’typical’ star-forming discs... Read More about KURVS: the outer rotation curve shapes and dark matter fractions of z ∼ 1.5 star-forming galaxies.

Overview of the DESI Milky Way Survey (2023)
Journal Article
Cooper, A. P., Koposov, S. E., Allende Prieto, C., Manser, C. J., Kizhuprakkat, N., Myers, A. D., Dey, A., Gänsicke, B. T., Li, T. S., Rockosi, C., Valluri, M., Najita, J., Deason, A., Raichoor, A., Wang, M.-Y., Ting, Y.-S., Kim, B., Carrillo, A., Wang, W., Beraldo e Silva, L., …Zou, H. (2023). Overview of the DESI Milky Way Survey. Astrophysical Journal, 947(1), Article 37. https://doi.org/10.3847/1538-4357/acb3c0

We describe the Milky Way Survey (MWS) that will be undertaken with the Dark Energy Spectroscopic Instrument (DESI) on the Mayall 4 m telescope at the Kitt Peak National Observatory. Over the next 5 yr DESI MWS will observe approximately seven millio... Read More about Overview of the DESI Milky Way Survey.

Characterisation of detachment in the MAST-U Super-X divertor using multi-wavelength imaging of 2D atomic and molecular emission processes (2023)
Journal Article
Wijkamp, T., Allcock, J., Feng, X., Kool, B., Lipschultz, B., Verhaegh, K., Duval, B., Harrison, J., Kogan, L., Lonigro, N., Perek, A., Ryan, P., Sharples, R., Classen, I., & Jaspers, R. (2023). Characterisation of detachment in the MAST-U Super-X divertor using multi-wavelength imaging of 2D atomic and molecular emission processes. Nuclear Fusion, 63(5), Article 056003. https://doi.org/10.1088/1741-4326/acc191

In this work, we provide the first 2D spatially resolved description of radiative detachment in MAST-U Super-X L-mode divertor plasmas. The Super-X magnetic configuration was designed to achieve reduced heat- and particle loads at the divertor target... Read More about Characterisation of detachment in the MAST-U Super-X divertor using multi-wavelength imaging of 2D atomic and molecular emission processes.

The Spectroscopic Data Processing Pipeline for the Dark Energy Spectroscopic Instrument (2023)
Journal Article
Guy, J., Bailey, S., Kremin, A., Alam, S., Alexander, D., Allende Prieto, C., BenZvi, S., Bolton, A., Brooks, D., Chaussidon, E., Cooper, A., Dawson, K., de la Macorra, A., Dey, A., Dey, B., Dhungana, G., Eisenstein, D., Font-Ribera, A., Forero-Romero, J., Gaztañaga, E., …Zou, H. (2023). The Spectroscopic Data Processing Pipeline for the Dark Energy Spectroscopic Instrument. Astrophysical Journal, 165(4), Article 144. https://doi.org/10.3847/1538-3881/acb212

We describe the spectroscopic data processing pipeline of the Dark Energy Spectroscopic Instrument (DESI), which is conducting a redshift survey of about 40 million galaxies and quasars using a purpose-built instrument on the 4 m Mayall Telescope at... Read More about The Spectroscopic Data Processing Pipeline for the Dark Energy Spectroscopic Instrument.

DESI Observations of the Andromeda Galaxy: Revealing the Immigration History of our Nearest Neighbor (2023)
Journal Article
Dey, A., Najita, J. R., Koposov, S., Josephy-Zack, J., Maxemin, G., Bell, E. F., Poppett, C., Patel, E., Beraldo e Silva, L., Raichoor, A., Schlegel, D., Lang, D., Meisner, A., Myers, A. D., Aguilar, J., Ahlen, S., Allende Prieto, C., Brooks, D., Cooper, A., Dawson, K., …Zou, H. (2023). DESI Observations of the Andromeda Galaxy: Revealing the Immigration History of our Nearest Neighbor. Astrophysical Journal, 944(1), Article 1. https://doi.org/10.3847/1538-4357/aca5f8

We present DESI observations of the inner halo of M31, which reveal the kinematics of a recent merger - a galactic immigration event - in exquisite detail. Of the 11,416 sources studied in 3.75 hours of on-sky exposure time, 7,438 are M31 sources wit... Read More about DESI Observations of the Andromeda Galaxy: Revealing the Immigration History of our Nearest Neighbor.

Wavelength calibration of birefringent interferometers for 2-D measurement of plasma flow (2023)
Journal Article
Allcock, J. S., Silburn, S. A., Sharples, R. M., Harrison, J. R., Conway, N. J., Long, T., & Lin, N. (2023). Wavelength calibration of birefringent interferometers for 2-D measurement of plasma flow. Optics Express, 31(2), 1901-1915. https://doi.org/10.1364/oe.473278

Imaging birefringent interferometers are used to measure plasma flow in 2-D via the Doppler shift of a spectral emission line. Applications include plasma physics study in fusion energy experiments and in the Earth’s upper atmosphere. We present a ne... Read More about Wavelength calibration of birefringent interferometers for 2-D measurement of plasma flow.

The Robotic Multiobject Focal Plane System of the Dark Energy Spectroscopic Instrument (DESI) (2022)
Journal Article
Silber, J. H., Fagrelius, P., Fanning, K., Schubnell, M., Aguilar, J. N., Ahlen, S., Ameel, J., Ballester, O., Baltay, C., Bebek, C., Beard, D. B., Besuner, R., Cardiel-Sas, L., Casas, R., Castander, F. J., Claybaugh, T., Dobson, C., Duan, Y., Dunlop, P., Edelstein, J., …Zou, H. (2023). The Robotic Multiobject Focal Plane System of the Dark Energy Spectroscopic Instrument (DESI). Astronomical Journal, 165(1), Article 9. https://doi.org/10.3847/1538-3881/ac9ab1

A system of 5,020 robotic fiber positioners was installed in 2019 on the Mayall Telescope, at Kitt Peak National Observatory. The robots automatically re-target their optical fibers every 10 - 20 minutes, each to a precision of several microns, with... Read More about The Robotic Multiobject Focal Plane System of the Dark Energy Spectroscopic Instrument (DESI).

Reconstruction of the emissivity and flow for Doppler coherence imaging spectroscopy (CIS) on J-TEXT (2022)
Journal Article
Li, B., Wang, T., Nie, L., Long, T., Zhang, X., Sharples, R., Xu, M., Wang, Z., Chen, Z., Wu, H., Liu, Z., Ke, R., Zhang, X., Jiao, S., Qing, W., Tian, Y., & Pan, Y. (2022). Reconstruction of the emissivity and flow for Doppler coherence imaging spectroscopy (CIS) on J-TEXT. Fusion Engineering and Design, 184, Article 113271. https://doi.org/10.1016/j.fusengdes.2022.113271

Doppler coherence imaging spectroscopy (CIS) has been installed on J-TEXT tokamak to provide a wealth of information for carbon impurity ions (CIII). To obtain the local emissivity and flow from the line-integrated information measured by the camera,... Read More about Reconstruction of the emissivity and flow for Doppler coherence imaging spectroscopy (CIS) on J-TEXT.

The HR image slicer for GNIRS at Gemini North: optical design and performance (2022)
Presentation / Conference Contribution
Calcines Rosario, A., Dubbeldam, C. M., Sharples, R., Bourgenot, C., Diaz, R., & Stephens, A. W. (2022, December). The HR image slicer for GNIRS at Gemini North: optical design and performance. Presented at Ground-based and Airborne Instrumentation for Astronomy IX

GNIRS (Gemini Near-InfraRed Spectrograph) is a multi-function spectrograph at Gemini North telescope offering four observational modes in the spectral range of 0.8 to 5.4 µm. It provides 2-pixel spectral resolutions from 1,200 up to 18,0000 and has s... Read More about The HR image slicer for GNIRS at Gemini North: optical design and performance.

The resolved chemical abundance properties within the interstellar medium of star-forming galaxies at z≈ 1.5 (2022)
Journal Article
Gillman, S., Puglisi, A., Dudzevičiūtė, U., Swinbank, A., Tiley, A., Harrison, C., Molina, J., Sharples, R., Bower, R., Cirasuolo, M., Ibar, E., & Obreschkow, D. (2022). The resolved chemical abundance properties within the interstellar medium of star-forming galaxies at z≈ 1.5. Monthly Notices of the Royal Astronomical Society, 512(3), 3480-3499. https://doi.org/10.1093/mnras/stac580

We exploit the unprecedented depth of integral field data from the KMOS Ultra-deep Rotational Velocity Survey (KURVS) to analyse the strong (Hα) and forbidden ([NII], [SII]) emission line ratios in 22 main-sequence galaxies at z ≈ 1.5. Using the [NII... Read More about The resolved chemical abundance properties within the interstellar medium of star-forming galaxies at z≈ 1.5.

Chronos: A NIR spectroscopic galaxy survey to probe the most fundamental stages of galaxy evolution (2021)
Journal Article
Ferreras, I., Cropper, M., Sharples, R., Bland-Hawthorn, J., Bruzual, G., Charlot, S., Conselice, C., Driver, S., Dunlop, J., Hopkins, A., Kaviraj, S., Kitching, T., Barbera, F. L., Lahav, O., Pasquali, A., Serjeant, S., Silk, J., & Windhorst, R. (2021). Chronos: A NIR spectroscopic galaxy survey to probe the most fundamental stages of galaxy evolution. Experimental Astronomy, 51(3), https://doi.org/10.1007/s10686-021-09702-2

We propose a dedicated, ultra-deep spectroscopic survey in the near infrared (NIR), that will target a mass-limited sample of galaxies during two of the most fundamental epochs of cosmic evolution: the formation of the first galaxies (at z ≳ 6; cosmi... Read More about Chronos: A NIR spectroscopic galaxy survey to probe the most fundamental stages of galaxy evolution.

2D measurements of plasma electron density using coherence imaging with a pixelated phase mask (2021)
Journal Article
Allcock, J., Silburn, S., Sharples, R., Harrison, J., Conway, N., & Vernimmen, J. (2021). 2D measurements of plasma electron density using coherence imaging with a pixelated phase mask. Review of Scientific Instruments, 92(7), Article 073506. https://doi.org/10.1063/5.0050704

In this paper, the pixelated phase mask (PPM) method of interferometry is applied to coherence imaging (CI)—a passive, narrowband spectral imaging technique for diagnosing the edge and divertor regions of fusion plasma experiments. Compared to previo... Read More about 2D measurements of plasma electron density using coherence imaging with a pixelated phase mask.

The KMOS galaxy evolution survey (KGES): the angular momentum of star-forming galaxies over the last ≍10 Gyr (2021)
Journal Article
Tiley, A. L., Gillman, S., Cortese, L., Swinbank, A., Dudzevičiūtė, U., Harrison, C., Smail, I., Obreschkow, D., Croom, S., Sharples, R., & Puglisi, A. (2021). The KMOS galaxy evolution survey (KGES): the angular momentum of star-forming galaxies over the last ≍10 Gyr. Monthly Notices of the Royal Astronomical Society, 506(1), 323-342. https://doi.org/10.1093/mnras/stab1692

We present the KMOS Galaxy Evolution Survey (KGES), a K-band Multi-Object Spectrograph (KMOS) study of the H α and [N II] emission from 288 K-band-selected galaxies at 1.2 ≲ z ≲ 1.8, with stellar masses in the range log10(M∗/M⊙)≈9 – 11.5. In this pap... Read More about The KMOS galaxy evolution survey (KGES): the angular momentum of star-forming galaxies over the last ≍10 Gyr.

Development of an 11-channel multi wavelength imaging diagnostic for divertor plasmas in MAST Upgrade (2021)
Journal Article
Feng, X., Calcines, A., Sharples, R., Lipschultz, B., Perek, A., Vijvers, W., Harrison, J., Allcock, J., Andrebe, Y., Duval, B., & Mumgaard, R. (2021). Development of an 11-channel multi wavelength imaging diagnostic for divertor plasmas in MAST Upgrade. Review of Scientific Instruments, 92(6), Article 063510. https://doi.org/10.1063/5.0043533

Divertor detachment and alternative divertor magnetic geometries are predicted to be promising approaches to handle the power exhaust of future fusion devices. In order to understand the detachment process caused by volumetric losses in alternative d... Read More about Development of an 11-channel multi wavelength imaging diagnostic for divertor plasmas in MAST Upgrade.

The evolution of gas-phase metallicity and resolved abundances in star-forming galaxies at z ≍ 0.6-1.8 (2020)
Journal Article
Gillman, S., Tiley, A., Swinbank, A., Dudzevičiūtė, U., Sharples, R., Smail, I., Harrison, C., Bunker, A. J., Bureau, M., Cirasuolo, M., Magdis, G. E., Mendel, T., & Stott, J. P. (2021). The evolution of gas-phase metallicity and resolved abundances in star-forming galaxies at z ≍ 0.6-1.8. Monthly Notices of the Royal Astronomical Society, 500(3), 4229-4247. https://doi.org/10.1093/mnras/staa3400

We present an analysis of the chemical abundance properties of ≈650 star-forming galaxies at z ≈ 0.6–1.8. Using integral-field observations from the K-band multi-object spectrograph (KMOS), we quantify the [N II]/H α emission-line ratio, a proxy for... Read More about The evolution of gas-phase metallicity and resolved abundances in star-forming galaxies at z ≍ 0.6-1.8.

Doppler coherence imaging of scrape-off-layer impurity flows in the HL-2A tokamak (2020)
Journal Article
Long, T., Allcock, J., Nie, L., Sharples, R., Xu, M., Ke, R., Zhang, S., Silburn, S., Howard, J., Yu, Y., Yuan, B., Wang, Z., Song, X., Liu, L., & Duan, X. (2020). Doppler coherence imaging of scrape-off-layer impurity flows in the HL-2A tokamak. Review of Scientific Instruments, 91(8), Article 083504. https://doi.org/10.1063/5.0005609

A new Doppler coherence imaging spectroscopy interferometer has been developed on the HL-2A tokamak for the scrape-off-layer impurity flow measurement. Its spatial resolution is estimated to be up to ∼0.8 mm in the horizontal direction and ∼9 mm in t... Read More about Doppler coherence imaging of scrape-off-layer impurity flows in the HL-2A tokamak.