A5024916144- Astronomy and Astrophysical Research
- Stellar, planetary, and galactic studies
- Adaptive optics and wavefront sensing
- Galaxies: Formation, Evolution, Phenomena
- Spacecraft Design and Technology
- Calibration and Measurement Techniques
- Gamma-ray bursts and supernovae
- Photocathodes and Microchannel Plates
- Astronomical Observations and Instrumentation
- Semiconductor Lasers and Optical Devices
- Advanced optical system design
- Astrophysical Phenomena and Observations
- Atmospheric Ozone and Climate
- Optical Coatings and Gratings
- Astrophysics and Star Formation Studies
- Radiation Effects in Electronics
- SAS software applications and methods
- Optical Systems and Laser Technology
- Space Exploration and Technology
- Laser-Matter Interactions and Applications
- Semiconductor materials and devices
- Radio Astronomy Observations and Technology
- solar cell performance optimization
- Astro and Planetary Science
- Optical Network Technologies
Laboratory for Atmospheric and Space Physics
2023-2024
The University of Texas at Austin
2016-2022
University of Colorado Boulder
2022
University of Wisconsin–Madison
2012-2014
Abstract The Hobby–Eberly Telescope (HET) Dark Energy Experiment (HETDEX) is undertaking a blind wide-field low-resolution spectroscopic survey of 540 deg 2 sky to identify and derive redshifts for million Ly α -emitting galaxies in the redshift range 1.9 < z 3.5. ultimate goal measure expansion rate universe at this epoch, sharply constrain cosmological parameters thus nature dark energy. A major multiyear Wide-Field Upgrade (WFU) HET was completed 2016 that substantially increased field...
The second generation Low Resolution Spectrograph (LRS2) is a new facility instrument for the Hobby-Eberly Telescope (HET) at McDonald Observatory. Designed as powerful spectroscopic follow-up platform, LRS2 based on design of HETs Visible Integral-field Replicable Unit (VIRUS) and provides integral field spectroscopy two seeing-limited fields 6"×12" with unity fill factor. replicable VIRUS has been leveraged to gain broad wavelength coverage from 370 nm 1.0 μm, spread between fiber-fed...
We present spectra and near-infrared images of a sample faint radio sources initially selected as promising high-redshift galaxy (HzRG) candidates. have determined redshifts for total 13 galaxies with ranging from $0.52\le z \le 5.72$. Our probes luminosities that are almost an order magnitude fainter than previous large samples at the highest redshifts. use photometry subsample these to calculate stellar masses using simple population models, find be in range $10^{10.8} - 10^{11.7}...
Abstract We measure the Balmer decrements of 23 brightest planetary nebulae (PNe) in inner bulge ( r ≲ 3′) M31 and deredden bright end region’s [O iii ] λ 5007 PN luminosity function. show that most luminous PNe produce ≳1200 L ⊙ power their line, implying central star luminosities at least ∼11,000 . Even with recent accelerated-evolution post-AGB models, such require masses excess 0.66 M main-sequence progenitors ∼2.5 Since M31's has very few intermediate-age stars, we conclude conventional...
The Visible Integral-field Replicable Unit Spectrograph (VIRUS) consists of 156 identical spectrographs (arrayed as 78 pairs, each with a pair spectrographs) fed by 35,000 fibers, 1.5 arcsec diameter, at the focus upgraded 10 m Hobby-Eberly Telescope (HET). VIRUS has fixed bandpass 350-550 nm and resolving power R~750. fibers are grouped into integral field units, 448 20 average length. is first example large-scale replication applied to optical astronomy capable surveying large areas sky,...
The development of high reflectivity, protective mirror coatings for the Lyman UV (λ < 120 nm) is essential enabling both CubeSats and large UVOIR missions to tap this rich bandpass. Aluminum mirrors with fluoride-based layers are baseline coating technology; these have been proven be stable, reliable, long flight heritage. However, despite their overall acceptable optical performance, efficiency current state-of-theart Al still insufficient in 100-120 nm wavelength range systems which...
The Visible Integral-field Replicable Unit Spectrograph (VIRUS) consists of 156 identical spectrographs (arrayed as 78 pairs) fed by 35,000 fibers, each 1.5 arcsec diameter, at the focus upgraded 10 m Hobby-Eberly Telescope (HET). VIRUS has a fixed bandpass 350-550 nm and resolving power R~700. is first example industrial-scale replication applied to optical astronomy capable surveying large areas sky, spectrally. concept offers significant savings engineering effort, cost, schedule when...
The Robert Stobie Spectrograph Near Infrared Instrument (RSS-NIR), a prime focus facility instrument for the 11-meter Southern African Large Telescope (SALT), is well into its laboratory integration and testing phase. RSS-NIR will initially provide imaging single or multi-object medium resolution spectroscopy in an 8 arcmin field of view at wavelengths 0.9 - 1.7 μm. Future modes, including tunable Fabry-Perot spectral polarimetry, have been designed can be easily added later. mate to...
Abstract We report the discovery of disappearance Mg ii , Al iii C iv and Si broad absorption lines (BALs) at same velocity (0.07 c ), accompanied by a new BAL emerging higher (up to 0.11 in quasar J0827+4252 z = 2.038. This is first (i) over ions (ii) weak emission-line (WLQ). The based on four spectra from Sloan Digital Sky Survey one follow-up spectrum Hobby–Eberly Telescope/Low-Resolution Spectrograph-2. simultaneous emergence different velocities, together with no variations Catalina...
The SPRITE (The Supernova remnants, Proxies for Re-Ionization Testbed Experiment) 12U CubeSat mission, funded by NASA and led the Laboratory Atmospheric Space Physics (LASP) at University of Colorado Boulder, will house first Far-UV (100-175 nm) long-slit spectrograph with access to Lyman UV (λ ⪅ 115 sub-arcminute imaging resolution. map high energy emission from diffuse gas allowing study star formation feedback in a critical, but rarely studied, regime on both stellar galactic scales. This...
The MANTIS (Monitoring Activity of Nearby sTars with uv Imaging and Spectroscopy) 16U CubeSat mission, led by the Laboratory for Atmospheric Space Physics (LASP) at University Colorado Boulder, plans to characterize high-energy stellar radiation that drives atmospheric photochemistry escape on extrasolar planets conducting simultaneous observations exoplanet host stars extreme-ultraviolet (100–1200A; EUV), far-ultraviolet (1300–2200A; FUV), near-ultraviolet (2200–3500A; NUV), visible...
VIRUS is a massively replicated spectrograph built for HETDEX, the Hobby Eberly Telescope Dark Energy Experiment. It consists of 156 channels within 78 units fed by 34944 fibers over 22 arcminute field upgraded HET. covers relatively narrow bandpass (350-550nm) at low resolution (R ~ 700) to target emission Lyman-alpha emitters (LAEs) HETDEX. first demonstration industrial style assembly line replication in optical astronomy. Installation and testing began November 2015. This winter we...
The Visible Integral Field Replicable Unit Spectrograph (VIRUS), the instrument for Hobby Eberly Telescope Dark Energy Experiment (HETDEX), consists of 78 replicable units, each with two integral field spectrographs. Each spectrograph has its own 2kx2k CCD detector 15 micron pixels. Following alignment, final stage prior to deployment unit is characterization 156 channels and their CCDs. We describe laboratory calibration system scripting that automates this process. Both fiber continuous...
We assemble a sample of 17 low metallicity (7.45 < log(O/H)+12 8.12) galaxies with z 0.1 found spectroscopically, without photometric pre-selection, in early data from the Hobby Eberly Telescope Dark Energy Experiment (HETDEX). Star forming that occupy lowest mass and end mass-metallicity relation tend to be under sampled continuum-based surveys as their spectra are typically dominated by emission newly stars. search for high [OIII]$\lambda$5007 / [OII]$\lambda$3727, implying highly ionized...
We assemble an unbiased sample of 29 galaxies with [O II] $\lambda 3727$ and/or III] 5007$ detections at $z < 0.15$ from the Hobby-Eberly Telescope Dark Energy Experiment (HETDEX) Pilot Survey (HPS). HPS finds without pre-selection based on their detected emission lines via integral field spectroscopy. Sixteen these objects were followed up second-generation, low resolution spectrograph (LRS2) upgraded Telescope. Oxygen abundances then derived strong using a Bayesian approach. find most fall...
The Supernova remnants Proxies for reIonization Testbed Experiment (SPRITE) CubeSat is designed to map shock emission in supernova and determine the escape fraction of hydrogen ionizing radiation star-forming galaxies. As a secondary objective, SPRITE will track stability new advanced 'eLiF' mirror coatings Micro Channel Plate (MCP) detector over mission's lifetime as they are sensitive molecular contamination, especially from organic compounds, silicones, well exposure water vapor. result,...
The VIRUS2 instrument is a new fiber-fed multiplexed integral field spectrograph consisting of 6 units, each with 4 spectral channels, to provide large on-sky area coverage coupled broad coverage. will be facility on the McDonald Observatory 2.7 m Harlan J Smith Telescope 2.33 arcminute view and 2.5 arcsecond sampling. employs novel beam-switch module within fiber feed split light into channels covering 370-930 nm at R~2000, while achieving very compact highly stable instrument. design...
3C 82 at a redshift of 2.87 is the most distant (Third Cambridge Catalogue) quasar. Thus, it strong candidate to have luminous radio lobes in Universe. belongs class compact steep spectrum sources. We use single dish and interferometric observations order model plasma state these powerful lobes. It estimated that long-term time-averaged jet power required fill with leptonic $\overline{Q} \approx 2.66 \pm 1.33 \times 10^{47} \rm{ergs/sec}$, among largest time averaged powers from Positing...
We report on the status of detector system for Robert Stobie Spectrograph Near Infrared Arm (RSS-NIR) Southern African Large Telescope (SALT). The is a HAWAII-2RG array with 1.7 μm cutoff wavelength. controller incorporates Teledyne cryogenic SIDECAR ASIC board inside dewar and an FPGA interface card, developed by Inter-University Centre Astronomy Astrophysics (IUCAA), outside dewar. Data acquisition software written IUCAA runs under Linux operating communicates to through USB fiber optic...
The study of solar system bodies in the ultraviolet is often extended sources, including vapor plumes, atmospheres, cometary tails, and planetary surfaces. These objects are traditionally studied with longslit spectrographs that can sample one dimension spatial information at a time - providing cross section object question. Ultraviolet Micromirror Imaging Spectrograph (UMIS) new instrument concept will bring integral-field spectroscopy to field for first time, effectively creating...