R. R. Joyce

Newcastle University

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Co-Authors

Kenneth H. Hinkle

NSF’s NOIRLab

Francis C. Fekel

Tennessee State University

T. Lebzelter

University of Vienna

David Sprayberry

National Solar Observatory

Albert M. Fowler

Optica

P. R. Wood

Australian National University

Stephen T. Ridgway

NSF’s NOIRLab

D. Y. Gezari

Goddard Space Flight Center

Lori Allen

NSF’s NOIRLab

M. E. Levi

Lawrence Berkeley National Laboratory

Cooperative Institutions

Kitt Peak National Observatory

138

Optica

118

Lawrence Berkeley National Laboratory

104

University of California, Berkeley

NSF’s NOIRLab

University of Arizona

Centre National de la Recherche Scientifique

Center for Astrophysics Harvard & Smithsonian

California Institute of Technology

The Ohio State University

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Papers

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ProtoDESI: risk reduction experiment for the Dark Energy Spectroscopic Instrument

Proceedings of SPIE, the International Society for Optical Engineering/Proceedings of SPIE (2016)

Parker Fagrelius C. Baltay C. Bebek Robert Besuner F. J. Castander

The Dark Energy Spectroscopic Instrument (DESI) is under construction to measure the expansion history of the Universe using the Baryon Acoustic Oscillation technique. The spectra of 40 million galaxies over 14,000 sq. deg. will be measured during the life of the experiment. A new prime focus corrector for the KPNO Mayall telescope will deliver light to 5000 fiber optic positioners. The fibers in turn feed ten broad-band spectrographs. We describe the ProtoDESI experiment, planned for installation and commissioning at the Mayall telescope in the fall of 2016, which will test the fiber positioning system for DESI. The ProtoDESI focal plate, consisting of 10 fiber positioners, illuminated fiducials, and a guide, focus and alignment (GFA) sensor module, will be installed behind the existing Mosaic prime focus corrector. A Fiber View Camera (FVC) will be mounted to the lower surface of the primary mirror cell and a subset of the Instrument Control System (ICS) will control the ProtoDESI subsystems, communicate with the Telescope Control System (TCS), and collect instrument monitoring data. Short optical fibers from the positioners will be routed to the back of the focal plane where they will be imaged by the Fiber Photometry Camera (FPC) or back-illuminated by a LED system. Target objects will be identified relative to guide stars, and using the GFA in a control loop with the ICS/TCS system, the guide stars will remain stable on pre-identified GFA pixels. The fiber positioners will then be commanded to the target locations and placed on the targets iteratively, using the FVC to centroid on back-illuminated fibers and fiducials to make corrective delta motions. When the positioners are aligned with the targets on-sky, the FPC will measure the intensities from the positioners' fibers which can then be dithered to look for intensity changes, indicating how well the fibers were initially positioned on target centers. The final goal is to operate ProtoDESI on the Mayall telescope for a 6-hour period during one night, successfully placing targets on the intended fibers for the duration of a typical DESI science exposure.

10.1117/12.2231760

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Citations (4)

Imaging Ejecta from the Final Flash Star V605 Aql

International Astronomical Union Colloquium (2002)

Kenneth H. Hinkle R. R. Joyce S. T. Ridgway Laird M. Close T. Lebzelter

Abstract The cloud of ejecta resulting from a final helium shell flash in V605 Aql has been imaged in both optical emission lines and infrared continuum. The obscuring circumstellar dust cloud, whose effects were first seen in 1923, is shown to be bipolar, suggesting dust formation takes place in a disk surrounding this star. The ongoing stellar mass loss in V605 Aql is part of the final flash episode, which has been ongoing since 1919. The pre-final flash planetary nebula, A58, is nearly circular. This implies that significant changes in the mass loss process occur between the AGB and final flash stages.

Star (game theory)

10.1017/s025292110000138x

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A study of bright Southern long period variables

Astronomy and Astrophysics (2005)

T. Lebzelter K. H. Hinkle P. R. Wood R. R. Joyce Francis C. Fekel

In this paper we present radial velocity curves of AGB variables that exhibit various kinds of anomalies: semiregular variables (SRVs) with typical mira periods, SRVs exceeding the mira 2.5 mag amplitude limit, miras with secondary maxima in their light curves, and a SRV with a long secondary period. The stars with reliable Hipparcos parallaxes from this and from previous studies are plotted in a -diagram. Our objects nicely follow the -relations determined for the LMC. This allows the pulsation mode to be identified. While all miras fall on the fundamental mode sequence, the SRVs fall on both the first overtone and fundamental mode sequences. The SRVs on the fundamental mode sequence occur at both high and low luminosities, some of them being more luminous than larger amplitude miras. This demonstrates observationally that some parameter other than luminosity affects the stability of long period variables, probably mass. First overtone pulsators all show velocity amplitudes around 4 km s-1. For the fundamental mode pulsators, the velocity amplitude shows a correlation with light amplitude. The two miras R Cen and R Nor, known for their double-peaked light curves, have velocity curves that are quite different. The R Nor velocity curve shows no evidence of the double peaks, meaning that the true pulsation period is the time between alternate minima or maxima. There is slight evidence for a double bump in the R Cen velocity curve. It is suggested that these stars are relatively massive (3–5 ).

Maxima

Overtone

Radial velocity

10.1051/0004-6361:20041575

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Citations (38)

Observations of 3.2-3.6 micron emission features in comet Halley

The Astrophysical Journal (1986)

R. F. Knacke T. Y. Brooke R. R. Joyce

view Abstract Citations (66) References (18) Co-Reads Similar Papers Volume Content Graphics Metrics Export Citation NASA/ADS Observations of 3.2--3.6 Micron Emission Features in Comet Halley Knacke, R. F. ; Brooke, T. Y. ; Joyce, R. R. Abstract Ground-based spectroscopic observations of the emission feature near 3.3 microns discovered in comet Halley by the Vega 1 spacecraft are reported. At a resolution of Delta gamma/gamma = 0.012 the emission consists of several components between 3.2 and 3.6 microns, and appears to be a superposition of C-H group bands. The feature is observed out to several thousand kilometers from the nucleus and does not appear to be thermal radiation from the grains responsible for the 4-20 micron continuum. Molecular scattering or emission by a component of cool (less than 400 K) grains would require near cosmic abundance of carbon. Hotter grains would radiate strongly enough to reduce the abundance requirement. The band shape is similar, but not identical, to interstellar absorption at 3.4 microns, to spectra of organic extracts from carbonaceous chondrites, and to spectra of some synthesized materials, such as 'QCCs' (as discussed by Sakata and colleagues in 1984). A newly found emission at 3.52 + or 0.02 microns is evidence for oxygen containing organic molecules, possibly formaldehyde or methanol. Publication: The Astrophysical Journal Pub Date: November 1986 DOI: 10.1086/184780 Bibcode: 1986ApJ...310L..49K Keywords: Halley'S Comet; Infrared Spectra; Interstellar Matter; Abundance; Cosmic Dust; Formaldehyde; Methyl Alcohol; Astrophysics; COMETS; INFRARED: SPECTRA; INTERSTELLAR: MATTER full text sources ADS |

Halley's Comet

Interstellar comet

Comet dust

10.1086/184780

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Citations (54)

A conceptual design for the Thirty Meter Telescope adaptive optics systems

Proceedings of SPIE, the International Society for Optical Engineering/Proceedings of SPIE (2006)

Brent L. Ellerbroek C. Boyer Colin Bradley M. C. Britton Steve Browne

In this paper, we provide an overview of the adaptive optics (AO) program for the Thirty Meter Telescope (TMT) project, including an update on requirements; the philosophical approach to developing an overall AO system architecture; the recently completed conceptual designs for facility and instrument AO systems; anticipated first light capabilities and upgrade options; and the hardware, software, and controls interfaces with the remainder of the observatory. Supporting work in AO component development, lab and field tests, and simulation and analysis is also discussed. Further detail on all of these subjects may be found in additional papers in this conference.

Upgrade

Conceptual design

10.1117/12.669422

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Citations (16)

The infrared view of dust and molecules around V4334 Sgr (Sakurai’s object): a 20-yr retrospective

Monthly Notices of the Royal Astronomical Society (2020)

A. Evans R. D. Gehrz C. E. Woodward D. Banerjee T. R. Geballe

We present an analysis of the evolution of circumstellar dust and molecules in the environment of the very late thermal pulse object V4334 Sgr (Sakurai's Object) over a $\sim20$-year period, drawing on ground-, airborne- and space-based infrared photometry and spectroscopy. The dust emission, which started in 1997, resembles a blackbody that cooled from $\sim1200$K in 1998 August to $\sim180$K in 2016 July. The dust mass, assuming amorphous carbon, was $\sim5\times10^{-10}$M$_\odot$ in 1998 August, and we estimate that the total dust mass was $\sim2\times10^{-5}$M$_\odot$ by $\sim2016$. The appearance of a near infrared excess in 2008 suggests a new episode of (or renewed) mass loss began then. We infer lower limits on the bolometric luminosity of the embedded star from that of the dust shell, which rose to $\sim16000$L$_\odot$ before declining to $\sim3000$L$_\odot$. There is evidence for weak 6-7$μ$m absorption, which we attribute to hydrogenated amorphous carbon formed in material ejected by Sakurai's Object during a mass ejection phase that preceded the 1997 event. We detect small hydrocarbon and other molecules in the spectra, and trace the column densities in hydrogen cyanide (HCN) and acetylene (C$_2$H$_2$). We use the former to determine the $^{12}$C/$^{13}$C ratio to be $6.4\pm0.7$, 14 times smaller than the Solar System value.

Black-body radiation

Amorphous carbon

10.1093/mnras/staa343

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Citations (16)

Optical design of the high-resolution near-infrared spectrograph

Proceedings of SPIE, the International Society for Optical Engineering/Proceedings of SPIE (2006)

Ming Liang R. R. Joyce S. S. Eikenberry K. H. Hinkle Gary Muller

HRNIRS is an extremely versatile high-resolution infrared facility spectrograph designed for the Gemini South telescope. Operating over the 1.05 - 5.5 micron wavelength range, it has the capability to carry out a wide range of scientific programs by incorporating two separate modes of operation. The first is a conventional single slit cross-dispersed mode providing spectral resolution R ~ 70000 with a 0.4 arcsec slit over as much as an octave in wavelength, thus covering most of the JHK or LM windows in a single observation. In this mode the spectrograph accepts the Gemini seeing-limited f/16 input over a small field. A built-in modulator and polarizer allow HRNIRS to measure both linear and circular polarization. The second mode is a moderately-high resolution (R ~ 30000) spectrograph observing multiple objects simultaneously within a 2 arcmin field fed by the f/33.2 Gemini MCAO beam. In this paper, we discuss the optical design considerations, present the resulting design and show that the predicted performance meets the design requirements.

Polarizer

Spectral resolution

Field of view

10.1117/12.671895

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Citations (2)

Infrared Spectroscopy of Symbiotic Stars. V. First Orbits for Three S-Type Systems: Henize 2-173, CL Scorpii, and AS 270

The Astronomical Journal (2006)

Francis C. Fekel Kenneth H. Hinkle R. R. Joyce P. R. Wood T. Lebzelter

Infrared radial velocities have been used to compute first orbits of the M giants in three southern S-type symbiotic systems. Of the three, Hen 2-173 has the longest orbital period, 911 days, and also has a noncircular orbit with an eccentricity of 0.21. The large value of its mass function suggests that Hen 2-173 may be an eclipsing system. For CL Sco our spectroscopic orbital period of 626 days is essentially identical to the previously determined light variability period of 625 days, and we have adopted the latter. AS 270 has an orbital period of similar length, 671 days, and both CL Sco and AS 270 have circular orbits. Only CL Sco has been extensively investigated previously, and we compare our results with the conclusions of Kenyon & Webbink. We also have examined the period-eccentricity relation for 30 S-type symbiotics. Circular orbits are found for 81% of the systems with orbital periods up to 800 days, while they occur for only 22% with periods greater than 800 days. This distribution is quite unlike that for G and K giants; rather, it is similar to that for barium stars, another type of mass-transfer binary, which also consists of a late-type giant and a white dwarf companion.

Orbital period

Eccentricity (behavior)

Radial velocity

Orbital elements

Orbit (dynamics)

10.1086/509133

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Citations (18)

Spectra of Cool Stars in the [ITAL]J[/ITAL] Band (1.0–1.3 μ[CLC]m[/CLC]) at Medium Resolution

The Astronomical Journal (1998)

R. R. Joyce Kenneth H. Hinkle Lloyd Wallace Michael Dulick David L. Lambert

A spectroscopic survey of 103 cool S-, C-, and M-type stars was undertaken with the Kitt Peak cryogenic spectrograph on the 1.3 m telescope to make a detailed search for new molecular bands in the 1.0–1.3 μm J-band region. While the spectra have high signal-to-noise ratios and good repeatability, no strong new features were found. Higher resolution spectra of a small sample of representative stars observed with the 4 m Fourier transform spectrometer were invoked in order to identify the features in these spectra. With few exceptions, the details of these spectra are well understood. Laboratory spectra were obtained to aid in the identification of some weak features. Spectral features from dominant lines of Ti, Fe, Al, Si, Mn, Na, and K, and molecular bands due to TiO, TiS, ZrO, ZrS, VO, H2O, and CN, have been identified in the spectra. Several weak unidentified bands are found.

10.1086/300594

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Citations (38)

Near infrared long slit spectra of NGC 1068.

Astronomical Society of the Pacific Conference Series eBooks (1991)

Motohide Tamura S. G. Kleinmann N. Z. Scoville R. R. Joyce

Long-slit spectra at 2.30 and 2.16 μm at a spectral resolution of 1200 are presented for the nucleus and inner disk of the Seyfert 2 galaxy NGC 1068, in order to study the stellar population and the ionized and molecular gas at wavelengths where the extinction is greatly reduced. At 6″-12″ from the nucleus, the CO (ν = 0-2) band head is seen in absorption at a level consistent with that seen in late K or nearly M giants. It is shallower than that of M82, a prototype of starburst galaxies, by ∼ 30%. Closer to the nucleus, the band head appears progressively weaker. This may be due to scattered nuclear light.

Extinction (optical mineralogy)

Stellar population

Source

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