S. W. Digel
A5070480015- Astrophysics and Cosmic Phenomena
- Gamma-ray bursts and supernovae
- Dark Matter and Cosmic Phenomena
- Astronomy and Astrophysical Research
- Stellar, planetary, and galactic studies
- Astronomical Observations and Instrumentation
- Particle Detector Development and Performance
- Adaptive optics and wavefront sensing
- Astrophysics and Star Formation Studies
- CCD and CMOS Imaging Sensors
- Scientific Research and Discoveries
- Calibration and Measurement Techniques
- Astro and Planetary Science
- Nuclear Physics and Applications
- Radio Astronomy Observations and Technology
- Particle physics theoretical and experimental studies
- Image and Signal Denoising Methods
- Distributed and Parallel Computing Systems
- Galaxies: Formation, Evolution, Phenomena
- Particle Accelerators and Free-Electron Lasers
- Pulsars and Gravitational Waves Research
- Atmospheric Ozone and Climate
- Solar and Space Plasma Dynamics
- Neutrino Physics Research
- Infrared Target Detection Methodologies
SLAC National Accelerator Laboratory
2013-2024
Kavli Institute for Particle Astrophysics and Cosmology
2013-2023
Stanford University
2012-2023
Menlo School
2005-2022
Stanford Synchrotron Radiation Lightsource
2006-2009
Center for Astrophysics Harvard & Smithsonian
1994-2007
Max Planck Institute for Extraterrestrial Physics
2007
University of California, Santa Cruz
2006
Goddard Space Flight Center
1996-2001
Universities Space Research Association
2000
(Abridged) We describe here the most ambitious survey currently planned in optical, Large Synoptic Survey Telescope (LSST). A vast array of science will be enabled by a single wide-deep-fast sky survey, and LSST have unique capability faint time domain. The design is driven four main themes: probing dark energy matter, taking an inventory Solar System, exploring transient optical sky, mapping Milky Way. wide-field ground-based system sited at Cerro Pach\'{o}n northern Chile. telescope 8.4 m...
view Abstract Citations (1007) References (25) Co-Reads Similar Papers Volume Content Graphics Metrics Export Citation NASA/ADS The Likelihood Analysis of EGRET Data Mattox, J. R. ; Bertsch, D. L. Chiang, Dingus, B. Digel, S. W. Esposito, A. Fierro, M. Hartman, C. Hunter, Kanbach, G. Kniffen, Lin, Y. Macomb, Mayer-Hasselwander, H. Michelson, P. F. von Montigny, Mukherjee, Nolan, Ramanamurthy, V. Schneid, E. Sreekumar, Thompson, Willis, T. use likelihood for the analysis high-energy γ-ray...
In three years of observations since the beginning nominal science operations in August 2008, Large Area Telescope (LAT) on board Fermi Gamma Ray Space has observed high-energy (>20 MeV) \gamma-ray emission from 35 gamma-ray bursts (GRBs). Among these, 28 GRBs have been detected above 100 MeV and 7 ~ 20 MeV. The first Fermi-LAT catalog is a compilation these detections provides systematic study for time. To generate catalog, we examined 733 by Gamma-Ray Burst Monitor (GBM) processed each...
Weakly interacting massive particles (WIMPs) are a theoretical class of that excellent dark matter candidates. WIMP annihilation or decay may produce essentially monochromatic γ rays detectable by the Fermi Large Area Telescope (LAT) against astrophysical γ-ray emission Galaxy. We have searched for spectral lines in energy range 5–300 GeV using 3.7 years data, reprocessed with updated instrument calibrations and an improved dispersion model compared to previous Fermi-LAT Collaboration line...
The Fermi Large Area Telescope (LAT) light curve repository (LCR) is a publicly available, continually updated library of gamma-ray curves variable Fermi-LAT sources generated over multiple timescales. LCR aims to provide publication-quality binned on timescales 3 days, 7 and 30 days for 1525 deemed in the source catalog first 10 years observations. consists through full likelihood analyses that model surrounding region, providing fluxes photon indices each time bin. intended as resource...
We use the GALPROP code for cosmic-ray (CR) propagation to calculate broad-band luminosity spectrum of Milky Way related CR and interactions in interstellar medium. This includes gamma-ray emission from production subsequent decay neutral pions, bremsstrahlung, inverse Compton scattering, synchrotron radiation. The Galaxy is found be nearly a electron calorimeter, but {\it only} if gamma ray emitting processes are taken into account. Synchrotron radiation alone accounts only one third total...
The contribution of unresolved sources to the diffuse gamma-ray background could induce anisotropies in this emission on small angular scales. We analyze power spectrum measured by Fermi LAT at Galactic latitudes |b| > 30 deg four energy bins spanning 1 50 GeV. At multipoles \ell \ge 155, corresponding scales \lesssim 2 deg, above photon noise level is detected >99.99% CL 1-2 GeV, 2-5 and 5-10 GeV bins, >99% 10-50 Within each bin takes approximately same value all suggesting that it...
The Large Synoptic Survey Telescope is designed to provide an unprecedented optical imaging dataset that will support investigations of our Solar System, Galaxy and Universe, across half the sky over ten years repeated observation. However, exactly how LSST observations be taken (the observing strategy or "cadence") not yet finalized. In this dynamically-evolving community white paper, we explore detailed performance anticipated science expected depend on small changes strategy. Using...
The Large Synoptic Survey Telescope (LSST) Dark Energy Science Collaboration (DESC) will use five cosmological probes: galaxy clusters, large scale structure, supernovae, strong lensing, and weak lensing. This Requirements Document (SRD) quantifies the expected dark energy constraining power of these probes individually together, with conservative assumptions about analysis methodology follow-up observational resources based on our current understanding evolution within field in coming...
We search for evidence of dark matter (DM) annihilation in the isotropic gamma-ray background (IGRB) measured with 50 months Fermi Large Area Telescope (LAT) observations. An improved theoretical description cosmological DM signal, based on two complementary techniques and assuming generic weakly interacting massive particle (WIMP) properties, renders more precise predictions compared to previous work. More specifically, we estimate cosmologically-induced intensity have an uncertainty a...
Abstract We describe the simulated sky survey underlying second data challenge (DC2) carried out in preparation for analysis of Vera C. Rubin Observatory Legacy Survey Space and Time (LSST) by LSST Dark Energy Science Collaboration (LSST DESC). Significant connections across multiple science domains will be a hallmark LSST; DC2 program represents unique modeling effort that stresses this interconnectivity way has not been attempted before. This encompasses full end-to-end approach: starting...
Gamma-ray binaries are stellar systems containing a neutron star or black hole with gamma-ray emission produced by an interaction between the components. These rare, even though binary evolution models predict dozens in our Galaxy. A search for Fermi Large Area Telescope (LAT) shows that 1FGL J1018.6-5856 exhibits intensity and spectral modulation 16.6 day period. We identified variable X-ray counterpart, which sharp maximum coinciding emission, as well O6V((f)) optical counterpart radio is...
Shortened abstract: Observations of the nearby Chamaeleon clouds in gamma rays with Fermi Large Area Telescope and thermal dust emission Planck IRAS have been used HI CO radio data to (i) map gas column densities different phases at dark neutral medium (DNM) transition between HI-bright CO-bright media; (ii) constrain CO-to-$H_2$ conversion factor, $X_{CO}$; (iii) probe properties per nucleon each phase spatially across clouds. We separated velocity modelled 0.4-100 GeV intensity, optical...
The Fermi-Large Area Telescope (LAT) First Source Catalog (1FGL) was released in 2010 February and the Fermi-LAT 2-Year (2FGL) appeared 2012 April, based on data from 24 months of operation. Since they were released, many follow up observations unidentified γ-ray sources have been performed new procedures for associating with potential counterparts at other wavelengths developed. Here we review characterize all associations as published 1FGL 2FGL catalogs basis multifrequency archival...
Astrophysical and cosmological observations currently provide the only robust, empirical measurements of dark matter. Future with Large Synoptic Survey Telescope (LSST) will necessary guidance for experimental matter program. This white paper represents a community effort to summarize science case studying fundamental physics LSST. We discuss how LSST inform our understanding properties matter, such as particle mass, self-interaction strength, non-gravitational couplings Standard Model,...
view Abstract Citations (69) References (45) Co-Reads Similar Papers Volume Content Graphics Metrics Export Citation NASA/ADS A Large-Scale CO Survey toward W3, W4, and W5 Digel, Seth W. ; Lyder, David A. Philbrick, Amy J. Puche, Daniel Thaddeus, Patrick J = 1-0 survey of the outer Galaxy is described. The bright molecular emission in W3 region Perseus arm prominent, little seen at greater Galactocentric distances. extensive local contains large cloud complex associated with Cam OB1. Between...
view Abstract Citations (76) References (39) Co-Reads Similar Papers Volume Content Graphics Metrics Export Citation NASA/ADS EGRET Observations of Gamma-Ray Emission from the Interstellar Gas in Orion Digel, S. W. ; Hunter, D. Mukherjee, R. The high-energy diffuse gamma-ray emission interstellar gas was studied using observations Energetic Experiment Telescope (EGRET) on Compton Observatory (CGRO) and radio surveys H I CO emission. good correlation with atomic molecular permits...
We present a catalog of gamma-ray sources at energies above 10 GeV based on data from the Large Area Telescope (LAT) accumulated during first 3 years Fermi Gamma-ray Space mission. This complements Second Fermi-LAT Catalog, which was 2 extending down to 100 MeV and so included many with softer spectra below GeV. The First Catalog >10 (1FHL) has 514 sources, includes their locations, spectra, measure variability, associations cataloged other wavelengths. found that 449 (87%) could be...
The multiscale variance stabilization Transform (MSVST) has recently been proposed for Poisson data denoising. This procedure, which is nonparametric, based on thresholding wavelet coefficients. We present in this paper an extension of the MSVST to 3D (in fact 2D-1D data) when third dimension not a spatial dimension, but wavelength, energy, or time. show that can be used detecting and characterizing astrophysical sources high-energy gamma rays, using realistic simulated observations with...
Abstract We present an analysis of eight years Fermi -LAT (>0.1 GeV) γ -ray data obtained for the radio galaxy NGC 1275. The flux from 1275 is highly variable on short (∼days to weeks) timescales, and has steadily increased over this year timespan. By examining changes in its spectral shape LAT energy band entire set, we found that behavior changed around 2011 February (∼MJD 55600). spectra at early times evolved largely high energies, while photon indices were unchanged later despite...
view Abstract Citations (49) References (58) Co-Reads Similar Papers Volume Content Graphics Metrics Export Citation NASA/ADS Gamma-Ray Observations of Ophiuchus with EGRET: The Diffuse Emission and Point Sources Hunter, S. D. ; Digel, W. de Geus, E. J. Kanbach, G. the region shade Energetic Gamma- Ray Experiment Telescope (EGRET) on Compton Gamma Observatory during first 2 1/2 years operation show diffuse emission from interstellar gas in as well variable two point sources. gamma-ray is...