David Davis
A5064329183- Astronomy and Astrophysical Research
- Gamma-ray bursts and supernovae
- Astrophysical Phenomena and Observations
- Galaxies: Formation, Evolution, Phenomena
- Astrophysics and Cosmic Phenomena
- Stellar, planetary, and galactic studies
- Astronomical Observations and Instrumentation
- Astrophysics and Star Formation Studies
- Ferroptosis and cancer prognosis
- Astro and Planetary Science
- Dark Matter and Cosmic Phenomena
- Atmospheric Ozone and Climate
- Various Chemistry Research Topics
- Phase Equilibria and Thermodynamics
- Cancer-related gene regulation
- Simulation-Based Education in Healthcare
- Isotope Analysis in Ecology
- Radio Astronomy Observations and Technology
- Chemical Thermodynamics and Molecular Structure
- Process Optimization and Integration
- American Constitutional Law and Politics
- History and Developments in Astronomy
- Spectroscopy and Laser Applications
- Technology Assessment and Management
- Epigenetics and DNA Methylation
Cincinnati Children's Hospital Medical Center
2016-2023
Clemson University
2022-2023
Construction Development (Qatar)
2023
University of Cincinnati
2016-2023
Rutgers Sexual and Reproductive Health and Rights
2023
Naval Postgraduate School
1991-2022
Union Presbyterian Seminary
2022
Mercer University Health Sciences Center
2021
University of Cincinnati Medical Center
2019
Bournville College
2007-2018
(Abridged) The Large Area Telescope (Fermi/LAT, hereafter LAT), the primary instrument on Fermi Gamma-ray Space (Fermi) mission, is an imaging, wide field-of-view, high-energy gamma-ray telescope, covering energy range from below 20 MeV to more than 300 GeV. This paper describes LAT, its pre-flight expected performance, and summarizes key science objectives that will be addressed. On-orbit performance presented in detail a subsequent paper. LAT pair-conversion telescope with precision...
ABSTRACT We present a catalog of high-energy gamma-ray sources detected by the Large Area Telescope (LAT), primary science instrument on Fermi Gamma-ray Space (Fermi) , during first 11 months phase mission, which began 2008 August 4. The First -LAT (1FGL) contains 1451 and characterized in 100 MeV to GeV range. Source detection was based average flux over month period, threshold likelihood Test Statistic is 25, corresponding significance just 4σ. 1FGL includes source location regions,...
We present the second catalog of high-energy gamma-ray sources detected by Large Area Telescope (LAT), primary science instrument on Fermi Gamma-ray Space (Fermi), derived from data taken during first 24 months phase mission, which began 2008 August 4. Source detection is based average flux over 24-month period. The Second Fermi-LAT (2FGL) includes source location regions, defined in terms elliptical fits to 95% confidence regions and spectral power-law, exponentially cutoff or log-normal...
The Fermi Large Area Telescope (Fermi-LAT, hereafter LAT), the primary instrument on Gamma-ray Space (Fermi) mission, is an imaging, wide field-of-view, high-energy γ-ray telescope, covering energy range from 20 MeV to more than 300 GeV. During first years of LAT team has gained considerable insight into in-flight performance instrument. Accordingly, we have updated analysis used reduce data for public release as well response functions (IRFs), description provided analysis. In this paper,...
We use Chandra data to map the gas temperature in central region of merging cluster A2142. The is markedly nonisothermal; it appears that cooling flow has been disturbed but not destroyed by a merger. X-ray image exhibits two sharp, bow-shaped, shock-like surface brightness edges or density discontinuities. However, and pressure profiles across these indicate are shock fronts. reasonably continuous edges, while entropy jumps opposite sense (i.e. denser side edge lower temperature, hence...
ABSTRACT Following its launch in 2008 June, the Fermi Gamma-ray Space Telescope ( ) began a sky survey August. The Large Area (LAT) on three months produced deeper and better resolved map of γ-ray than any previous space mission. We present here initial results for energies above 100 MeV 205 most significant (statistical significance greater ∼10σ) sources these data. These are best characterized localized point-like (i.e., spatially unresolved) early mission
Aims.We present a uniform catalog of the images and radial profiles temperature, abundance, brightness for 70 clusters galaxies observed by XMM-Newton.
The Fermi Gamma-ray Space Telescope has detected the gamma-ray glow emanating from giant radio lobes of galaxy Centaurus A. resolved image shows clearly separated central active source. In contrast to all other galaxies so far in high-energy gamma-rays, lobe flux constitutes a considerable portion (>1/2) total source emission. emission is interpreted as inverse Compton scattered relic radiation cosmic microwave background (CMB), with additional contribution at higher energies...
We present the first high-resolution X-ray image of jet in M87 using Chandra X-Ray Observatory. There is clear structure and almost all optically bright knots are detected individually. The unresolved core brightest feature but only 2-3 times brighter than knot A (123 from core) inner HST-1 (10 core). optical positions consistent at 01 level, emission (A) marginally upstream peak. Detailed Gaussian fits to one-dimensional profile show distinct that not associated with specific features....
We report the Fermi Large Area Telescope (LAT) discovery of high-energy (MeV/GeV) γ-ray emission positionally consistent with center radio galaxy M87, at a source significance over 10σ in 10 months all-sky survey data. Following detections Cen A and Per A, this makes M87 third seen LAT. The faint point-like has >100 MeV flux 2.45 (±0.63) × 10−8 photons cm−2 s−1 (photon index = 2.26 ± 0.13) no significant variability detected within LAT observation. This is comparable previous EGRET upper...
Analysis is presented for 15 months of data taken with the Large Area Telescope (LAT) on Fermi Gamma-ray Space 11 non-blazar active galactic nuclei (AGNs), including seven FRI radio galaxies and four FRII sources consisting two steep spectrum quasars. The broad line galaxy 3C 120 reported here as a γ-ray source first time. analysis based directional associations LAT in 3CR, 3CRR, MS4 (collectively referred to 3C-MS) catalogs. Seven eleven associated 3C-MS have spectral indices larger than...
We present γ-ray observations with the Large Area Telescope (LAT) on board Fermi Gamma-Ray Space of nearby radio galaxy Centaurus A (Cen A). The previous EGRET detection is confirmed, and localization improved using data from first 10 months science operation. In work, we presented lobes by LAT; in this concentrate core Cen A. Flux levels as seen LAT are not significantly different that found EGRET, nor extremely soft spectrum (Γ = 2.67 ± 0.10stat 0.08sys where photon flux Φ ∝ E−Γ)....
The Vela pulsar is the brightest persistent source in GeV sky and thus traditional first target for new gamma-ray observatories. We report here on initial Fermi Large Area Telescope observations during verification phase pointed exposure early survey scanning. have used signal to verify timing angular resolution. high quality pulse profile, with some 32,400 pulsed photons at E>0.03 GeV, shows features, including structure as fine 0.3ms a distinct third peak, which shifts energy. examine...
view Abstract Citations (209) References (34) Co-Reads Similar Papers Volume Content Graphics Metrics Export Citation NASA/ADS The Intragroup Medium in Poor Groups of Galaxies Mulchaey, John S. ; Davis, David Mushotzky, Richard F. Burstein, We have used the ROSAT PSPC to search for diffuse, extended X-ray emission a sample 14 galaxy groups. A diffuse component was found four cases. Combining our new analysis with published observations, we that total 48 groups varying size and velocity...
A search was conducted for a hot intragroup medium in 109 low-redshift galaxy groups observed with the ROSAT PSPC. Evidence diffuse, extended X-ray emission is found at least 61 groups. Approximately one-third of these detections have not been previously reported literature. Most are detected out to less than half virial radius ROSAT. Although some spiral-rich do contain an medium, diffuse restricted that one early-type galaxy.
High-resolution spectra of the active binary Capella (G8 III + G1 III) covering energy range 0.4-8.0 keV (1.5-30 Å) show a large number emission lines, demonstrating performance High-Energy Transmission Grating Spectrometer. A preliminary application plasma diagnostics provides information on coronal temperatures and densities. Lines arising from different elements in ionization states indicate that has with broad temperatures, log T = 6.3 to 7.2, generally consistent recent results...
We report the first detection of an OVIII Ly-alpha absorption line associated with overdense region in intergalactic medium (IGM) along sightline towards PKS 2155-304 Chandra Low Energy Transmission Grating Spectrometer (LETGS). The is detected at 4.5 sigma level cz~16,600 km/s. At same velocity Shull et al.(1998) a small group spiral galaxies (with overdensity delta_gal ~ 100) and low metallicity HI clouds. constrain intragroup gas that gives rise to baryon density range 1e-5 < n_b 7.5e-5...
Energetic young pulsars and expanding blast waves (supernova remnants, SNRs) are the most visible remains after massive stars, ending their lives, explode in core-collapse supernovae. The Fermi Gamma-Ray Space Telescope has unveiled a radio quiet pulsar located near center of compact synchrotron nebula inside supernova remnant CTA 1. pulsar, discovered through its gamma-ray pulsations, period 316.86 ms, derivative 3.614 x 10-13 s s-1 . Its characteristic age 104 years is comparable to that...
ABSTRACT We report the Fermi Large Area Telescope detection of extended γ -ray emission from lobes radio galaxy Fornax A using 6.1 years Pass 8 data. After Centaurus A, this is now second example an source attributed to a galaxy. Both flat disk morphology and following were preferred over point-source description, core contribution was constrained be <?CDATA $\lt 14$?> % total flux. alignment elongation with demonstrated by rotating template. found no significant evidence for variability on...
view Abstract Citations (80) References (32) Co-Reads Similar Papers Volume Content Graphics Metrics Export Citation NASA/ADS The middle-infrared spectrum of Saturn - Evidence for phosphine and upper limits to other trace atmospheric constituents Larson, H. P. ; Fink, U. Smith, A. Davis, D. S. Observations at high spectral resolution in the middle-IR region (2.5-5.6 microns) were obtained using a Fourier spectrometer ground-based airborne observatories. These spectra establish that PH3...
The BL Lacertae object 3C 66A was detected in a flaring state by the Fermi Large Area Telescope (LAT) and VERITAS 2008 October. In addition to these gamma-ray observations, F-GAMMA, GASP-WEBT, PAIRITEL, MDM, ATOM, Swift, Chandra provided radio X-ray coverage. available light curves show variability and, particular, correlated flares are observed optical Fermi-LAT band. resulting spectral energy distribution can be well fitted using standard leptonic models with without an external radiation...
ADVERTISEMENT RETURN TO ISSUEPREVArticleNEXTPressure-Temperature Charts—Extended Ranges.George Calingaert and D. S. DavisCite this: Ind. Eng. Chem. 1925, 17, 12, 1287–1288Publication Date (Print):December 1, 1925Publication History Published online1 May 2002Published inissue 1 December 1925https://pubs.acs.org/doi/10.1021/ie50192a037https://doi.org/10.1021/ie50192a037research-articleACS PublicationsRequest reuse permissionsArticle Views217Altmetric-Citations18LEARN ABOUT THESE METRICSArticle...
ADVERTISEMENT RETURN TO ISSUEPREVArticleNEXTComparative Absorption Rates for Various Gases.W. G. Whitman and D. S. DavisCite this: Ind. Eng. Chem. 1924, 16, 12, 1233–1237Publication Date (Print):December 1, 1924Publication History Published online1 May 2002Published inissue 1 December 1924https://pubs.acs.org/doi/10.1021/ie50180a008https://doi.org/10.1021/ie50180a008research-articleACS PublicationsRequest reuse permissionsArticle Views178Altmetric-Citations18LEARN ABOUT THESE METRICSArticle...