We present a new calibration of the J-band absolute magnitude of the JAGB method based on thermally pulsing AGB stars that are members of Milky Way open clusters, having distances and reddenings, independently compiled and published by Marigo. A total 17 of these photometrically selected J-Branch AGB stars give M ( J ) = -6.40 mag with a scatter of +/- 0.40 mag, and 1 sigma on the mean of +/- 0.10 mag. Combining the Milky Way field carbon star calibration of Lee with this determination gives a weighted average of M ( J )(MW) = -6.19 +/- 0.04 mag (error on the mean). This value is statistically indistinguishable from the value determined for this population of distance indicators in the LMC and SMC, giving further evidence that JAGB stars are extremely reliable distance indicators of high luminosity and universal applicability. Combining the zero-points for JAGB stars in these three systems, a value of M ( J ) = -6.20 +/- 0.01 (stat) +/- 0.04 (sys) mag becomes our best current estimate of the JAGB zero-point and its associated errors. Finally, we note that no evidence is found for any statistically significant dependence of this zero-point on metallicity.

Plasma membrane phosphatidylinositol (PI) 4-phosphate (PtdIns4P) has critical functions via both direct interactions and metabolic conversion to PI 4, 5-bisphosphate (PtdIns(4,5)P-2) and other downstream metabolites. However, mechanisms that control this PtdIns4P pool in cells of higher eukaryotes remain elusive. PI4KIII alpha, the enzyme thought to synthesize this PtdIns4P pool, is reported to localize in the ER, contrary to the plasma membrane localization of its yeast homologue, Stt4. In this paper, we show that PI4KIII alpha was targeted to the plasma membrane as part of an evolutionarily conserved complex containing Efr3/rolling blackout, which we found was a palmitoylated peripheral membrane protein. PI4KIII alpha knockout cells exhibited a profound reduction of plasma membrane PtdIns4P but surprisingly only a modest reduction of PtdIns(4,5)P-2 because of robust up-regulation of PtdIns4P 5-kinases. In these cells, however, much of the PtdIns(4,5)P-2 was localized intracellularly, rather than at the plasma membrane as in control cells, along with proteins typically restricted to this membrane, revealing a major contribution of PI4KIII alpha to the definition of plasma membrane identity.

We present a status update for MagAO-X, a 2000 actuator, 3.6 kHz adaptive optics and coronagraph system for the Magellan Clay 6.5 m telescope. MagAO-X is optimized for high contrast imaging at visible wavelengths. Our primary science goals are detection and characterization of Solar System-like exoplanets, ranging from very young, still-accreting planets detected at H-alpha, to older temperate planets which will be characterized using reflected starlight. First light was in Dec, 2019, but subsequent commissioning runs were canceled due to COVID-19. In the interim, MagAO-X has served as a lab testbed. Highlights include implementation of several focal plane and low-order wavefront sensing algorithms, development of a new predictive control algorithm, and the addition of an IFU module. MagAO-X also serves as the AO system for the Giant Magellan Telescope High Contrast Adaptive Optics Testbed. We will provide an overview of these projects, and report the results of our commissioning and science run in April, 2022. Finally, we will present the status of a comprehensive upgrade to MagAO-X to enable extreme-contrast characterization of exoplanets in reflected light. These upgrades include a new post-AO 1000-actuator deformable mirror inside the coronagraph, latest generation sCMOS detectors for wavefront sensing, optimized PIAACMC coronagraphs, and computing system upgrades. When these Phase II upgrades are complete we plan to conduct a survey of nearby exoplanets in reflected light.

We present millimeter, optical, and soft X-ray observations of a stellar flare with an energy squarely in the regime of typical X1 solar flares. The flare was observed from Proxima Cen on 2019 May 6 as part of a larger multi-wavelength flare monitoring campaign and was captured by Chandra, the Las Cumbres Observatory Global Telescope, the Irene du Pont Telescope at Las Campanas Observatory, and the Atacama Large Millimeter Array. Millimeter emission appears to be a common occurrence in small stellar flares that had gone undetected until recently, making it difficult to interpret these events within the current multi-wavelength picture of the flaring process. The May 6 event is the smallest stellar millimeter flare detected to date. We compare the relationship between the soft X-ray and millimeter emission to that observed in solar flares. The X-ray and optical flare energies of 10(30.3 +/- 0.2) and 10(28.9 +/- 0.1) erg, respectively, the coronal temperature of T = 11.0 +/- 2.1 MK, and the emission measure of 9.5 +/- 2.2 x 10(49) cm(-3) are consistent with M-X class solar flares. We find the soft X-ray and millimeter emission during quiescence are consistent with the Gudel-Benz relation, but not during the flare. The millimeter luminosity is >100x higher than that of an equivalent X1 solar flare and lasts only seconds instead of minutes as seen for solar flares.

GMTNIRS (Giant Magellan Telescope Near-Infrared Spectrograph) is a high resolution (R = 65,000 - 80,000) wide-band near-infrared spectrograph, one of the first-generation instruments of the Giant Magellan Telescope. We present the preliminary design of the electronics system including temperature control, power distribution, vacuum pressure monitoring, moving mechanism, and packaging. Design for infrared detector subsystems for science bands (J, H, K, L, and M) and a slit-view camera is planned. The electronics system makes use of EtherCAT as fieldbus standard according to the requirement of the GMT.

GMTNIRS, the Giant Magellan Telescope Near-Infrared Spectrograph, is a high resolution (R=65,000 similar to 80,000) near-infrared spectrograph selected as a first-generation instrument for the Giant Magellan Telescope. The instrument covers J, H, K, L, and M spectral bands in a single shot through 6-channel spectrographs. The L band is shared by two channels. Thanks to the use of silicon immersion gratings, the design is compact for its capability. GMTNIRS will be located on the GMT instrument rotator upper disk and operating in adaptive optics mode. We detail the optical system design, imaging performance, spectral formats, and fabrication/alignment budget.

GMTNIRS, the Giant Magellan Telescope Near-Infrared Spectrograph, is a high resolution (R = 65,000 - 80,000) nearinfrared spectrograph selected as a first-generation instrument for the Giant Magellan Telescope ( GMT). It simultaneously observes the J, H, K, L, and M bands using five immersion gratings. GMTNIRS will be located on the GMT instrument rotator upper disk and operating in adaptive optics mode. The cryostat and optical bench design is based on the heritage of the highly successful immersion grating spectrograph, IGRINS. The cryostat is octagonal with a width of 1.7 m and a height of 1 m. It consists of top piece, bottom plate, passive radiation shields, and warm window assembly. Cryocoolers, electronics, and vacuum components are installed on the bottom plate. The optical bench system is comprised of two optical benches, bench interface structure, and active radiation shield. It is thermally isolated from the cryostat by eight sets of G10 supports. The sub-bench accommodates the fore-optics, a pupil mask, and an oninstrument wave front sensor, while the spectrographs, slit-mask imager, and slit viewing camera are located on the main bench. Structure and thermal analysis have been performed to verify bench flexure by gravity vector change, integrity of the cryostat by vacuum pressure, and temperature distribution at the operating temperature of 70 K. We also present some design strategies to prevent light leakage.

GMTNIRS, the first-generation instrument of the Giant Magellan Telescope, is a high-resolution (R = 65,000 80,000) near-infrared spectrograph. We introduce the preliminary design of optical mounts for slit, beam splitters, and mirrors installed in the cryogenic spectrograph. Optical components are mounted on aluminum structures and fixed by titanium springs and spring plungers. Static analysis of optical mounts with 1g-force at various directions has been performed to verify the stability of the optical system. In addition, stability in the seismic environment is evaluated with modal analysis and non-linear dynamic analysis. Design and simulation results are compared to the tolerance limits of the system.

Solar contamination, due to moonlight and atmospheric scattering of sunlight, can cause systematic errors in stellar radial velocity (RV) measurements that significantly detract from the similar to 10 cm s(-1) sensitivity required for the detection and characterization of terrestrial exoplanets in or near habitable zones of Sun-like stars. The addition of low-level spectral contamination at variable effective velocity offsets introduces systematic noise when measuring velocities using classical mask-based or template-based cross-correlation techniques. Here we present simulations estimating the range of RV measurement error induced by uncorrected scattered sunlight contamination. We explore potential correction techniques, using both simultaneous spectrometer sky fibers and broadband imaging via coherent fiber imaging bundles, that could reliably reduce this source of error to below the photon-noise limit of typical stellar observations. We discuss the limitations of these simulations, the underlying assumptions, and mitigation mechanisms. We also present and discuss the components designed and built into the NEID (NN-EXPLORE Exoplanet Investigations with Doppler spectroscopy) precision RV instrument for the WIYN 3.5 m telescope, to serve as an ongoing resource for the community to explore and evaluate correction techniques. We emphasize that while "bright time" has been traditionally adequate for RV science, the goal of 10 cm s(-1) precision on the most interesting exoplanetary systems may necessitate access to darker skies for these next-generation instruments.