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EUV pattern defect detection sensitivity based on aerial image linewidth measurements

Description: As the quality of EUV-wavelength mask inspection microscopes improves over time, the image properties and intensity profiles of reflected light can be evaluated in ever-greater detail. The SEMATECH Berkeley Actinic Inspection Tool (AIT) is one such microscope, featuring mask resolution values that match or exceed those available through lithographic printing in current photoresists. In order to evaluate the defect detection sensitivity of the AIT for dense line patterns on typical masks, the authors study the line width roughness (LWR) on two masks, as measured in the EUV images. They report the through-focus and pitch dependence of contrast, image log slope, linewidth, and LWR. The AIT currently reaches LWR 3{sigma} values close to 9 nm for 175 nm half-pitch lines. This value is below 10% linewidth for nearly all lines routinely measured in the AIT. Evidence suggests that this lower level may arise from the mask's inherent pattern roughness. While the sensitivity limit of the AlT has not yet been established, it is clear that the AIT has the required sensitivity to detect defects that cause 10% linewidth changes in line sizes of 125 nm and larger.
Date: February 12, 2010
Creator: Goldberg, K. A.; Mochi, I.; Naulleau, P.; Liang, T.; Yan, P.-Y. & Huh, S.
Partner: UNT Libraries Government Documents Department

Pressure Dependence of Line Widths of Microwave Spectra of Sulphur Dioxide

Description: Measurements of line width parameters for eleven rotational transitions of type (J -- J + 1) of SO2 were made and are reported herein. The line width quantum number (J) trend was obtained. The microwave spectrograph used for these measurements of line width is described. Operational methods to operate the spectrograph are presented and discussed, with particular attention given to how to measure the line width. Suggestions for future avenues of probing this molecule to ascertain the non-uniform behavior of the line width parameter over the quantum number and frequency range are given.
Date: December 1972
Creator: Yang, Wei Han
Partner: UNT Libraries

Nearby Supernova Factory Observations of SN 2005gj: Another TypeIa Supernova in a Massive Circumstellar Envelope

Description: We report the independent discovery and follow-up observations of supernova 2005gj by the Nearby Supernova Factory. This is the second confirmed case of a ''hybrid'' Type Ia/IIn supernova, which like the prototype SN 2002ic, we interpret as the explosion of a white dwarf interacting with a circumstellar medium. Our early-phase photometry of SN 2005gj shows that the strength of the interaction between the supernova ejecta and circumstellar material is much stronger than for SN 2002ic. Our .rst spectrum shows a hot continuum with broad and narrow H{alpha} emission. Later spectra, spanning over 4 months from outburst, show clear Type Ia features combined with broad and narrow H{gamma}, H{beta},H{alpha} and He I {lambda}{lambda}5876,7065 in emission. At higher resolution, P Cygni profiles are apparent. Surprisingly, we also observe an inverted P Cygni profile for [O III] {lambda}5007. We find that the lightcurve and measured velocity of the unshocked circumstellar material imply mass loss as recently as 8 years ago. This is in contrast to SN 2002ic, for which an inner cavity in the circumstellar material was inferred. Within the context of the thin-shell approximation, the early lightcurve is well-described by a flat radial density profile for the circumstellar material. However, our decomposition of the spectra into Type Ia and shock emission components allows for little obscuration of the supernova, suggesting an aspherical or clumpy distribution for the circumstellar material. We suggest that the emission line velocity profiles arise from electron scattering rather than the kinematics of the shock. This is supported by the inferred high densities, and the lack of evidence for evolution in the line widths. Ground- and space-based photometry, and Keck spectroscopy, of the host galaxy are used to ascertain that the host galaxy has low metallicity (Z/Z{sub {circle_dot}} < 0.3; 95% confidence) and that this galaxy is undergoing a ...
Date: June 1, 2006
Creator: Aldering, G.; Antilogus, P.; Bailey, S.; Baltay, C.; Bauer, A.; Blanc, N. et al.
Partner: UNT Libraries Government Documents Department

Performance of actinic EUVL mask imaging using a zoneplatemicroscope

Description: The SEMATECH Berkeley Actinic Inspection Tool (AIT) is a dual-mode, scanning and imaging extreme-ultraviolet (EUV) microscope designed for pre-commercial EUV mask research. Dramatic improvements in image quality have been made by the replacement of several critical optical elements, and the introduction of scanning illumination to improve uniformity and contrast. We report high quality actinic EUV mask imaging with resolutions as low as 100-nm half-pitch, (20-nm, 5x wafer equivalent size), and an assessment of the imaging performance based on several metrics. Modulation transfer function (MTF) measurements show high contrast imaging for features sizes close to the diffraction-limit. An investigation of the illumination coherence shows that AIT imaging is much more coherent than previously anticipated, with {sigma} below 0.2. Flare measurements with several line-widths show a flare contribution on the order of 2-3% relative intensity in dark regions above the 1.3% absorber reflectivity on the test mask used for these experiments. Astigmatism coupled with focal plane tilt are the dominant aberrations we have observed. The AIT routinely records 250-350 high-quality images in numerous through-focus series per 8-hour shift. Typical exposure times range from 0.5 seconds during alignment, to approximately 20 seconds for high-resolution images.
Date: August 20, 2007
Creator: Goldberg, Kenneth A.; Naulleau, Patrick P.; Barty, Anton; Rekawa,Senajith B.; Kemp, Charles D.; Gunion, Robert F. et al.
Partner: UNT Libraries Government Documents Department

Measurement of quasi-ballistic heat transport across nanoscale interfaces using ultrafast coherent soft x-ray beams

Description: Understanding heat transport on nanoscale dimensions is important for fundamental advances in nanoscience, as well as for practical applications such as thermal management in nano-electronics, thermoelectric devices, photovoltaics, nanomanufacturing, as well as nanoparticle thermal therapy. Here we report the first time-resolved measurements of heat transport across nanostructured interfaces. We observe the transition from a diffusive to a ballistic thermal transport regime, with a corresponding increase in the interface resistivity for line widths smaller than the phonon mean free path in the substrate. Resistivities more than three times higher than the bulk value are measured for the smallest line widths of 65 nm. Our findings are relevant to the modeling and design of heat transport in nanoscale engineered systems, including nanoelectronics, photovoltaics and thermoelectric devices.
Date: March 2, 2009
Creator: Siemens, M.; Li, Q.; Yang, R.; Nelson, K.; Anderson, E.; Murnane, M. et al.
Partner: UNT Libraries Government Documents Department

ICPES analyses using full image spectra and astronomical data fitting algorithms to provide diagnostic and result information

Description: ICP emission analyses are prone to errors due to changes in power level, nebulization rate, plasma temperature, and sample matrix. As a result, accurate analyses of complex samples often require frequent bracketing with matrix matched standards. Information needed to track and correct the matrix errors is contained in the emission spectrum. But most commercial software packages use only the analyte line emission to determine concentrations. Changes in plasma temperature and the nebulization rate are reflected by changes in the hydrogen line widths, the oxygen emission, and neutral ion line ratios. Argon and off-line emissions provide a measure to correct the power level and the background scattering occurring in the polychromator. The authors` studies indicated that changes in the intensity of the Ar 404.4 nm line readily flag most matrix and plasma condition modifications. Carbon lines can be used to monitor the impact of organics on the analyses and calcium and argon lines can be used to correct for spectral drift and alignment. Spectra of contaminated groundwater and simulated defense waste glasses were obtained using a Thermo Jarrell Ash ICP that has an echelle CID detector system covering the 190-850 nm range. The echelle images were translated to the FITS data format, which astronomers recommend for data storage. Data reduction packages such as those in the ESO-MIDAS/ECHELLE and DAOPHOT programs were tried with limited success. The radial point spread function was evaluated as a possible improved peak intensity measurement instead of the common pixel averaging approach used in the commercial ICP software. Several algorithms were evaluated to align and automatically scale the background and reference spectra. A new data reduction approach that utilizes standard reference images, successive subtractions, and residual analyses has been evaluated to correct for matrix effects.
Date: October 1, 1997
Creator: Spencer, W.A. & Goode, S.R.
Partner: UNT Libraries Government Documents Department

Magnetic Semiconductor Quantum Wells in High Fields to 60 Tesla: Photoluminescence Linewidth Annealing at Magnetization Steps

Description: Magnetic semiconductors offer a unique possibility for strongly tuning the intrinsic alloy disorder potential with applied magnetic field. We report the direct observation of a series of step-like reductions in the magnetic alloy disorder potential in single ZnSe/Zn(Cd,Mn)Se quantum wells between O and 60 Tesla. This disorder, measured through the linewidth of low temperature photoluminescence spectra drops abruptly at -19, 36, and 53 Tesla, in concert with observed magnetization steps. Conventional models of alloy disorder (developed for nonmagnetic semiconductors) reproduce the general shape of the data, but markedly underestimate the size of the linewidth reduction.
Date: May 24, 1999
Creator: Awschalom, D.D.; Crooker, S.A.; Lyo, S.K.; Rickel, D.G. & Samarth, N.
Partner: UNT Libraries Government Documents Department

High-Resolution Transmission Electron Microscopy Calibration of Critical Dimension (CD) Reference Materials

Description: NIST and Sandia have developed a procedure for producing and calibrating critical dimension (CD), or linewidth, reference materials. These reference materials will be used to calibrate metrology instruments used in semiconductor manufacturing. The artifacts, with widths down to 100 nm, are produced in monocrystalline silicon with all feature edges aligned to specific crystal planes. A two-part calibration of these linewidths is used: the primary calibration, with accuracy to within a few lattice plane thicknesses, is accomplished by counting the lattice planes across the sample as-imaged through use of high-resolution transmission electron microscopy (HRTEM). The secondary calibration is the high-precision electrical CD technique. NIST and Sandia are developing critical dimension (CD), or linewidth, reference materials for use by the semiconductor industry. To meet the current requirements of this rapidly changing industry, the widths of the reference features must be at or below the widths of the finest features in production and/or development. Further, these features must produce consistent results no matter which metrology tool (e.g., scanning electron microscope, scanned probe microscope, electrical metrology) is used to make the measurement. This leads to a requirement for the samples to have planar surfaces, known sidewall angles, and uniform material composition. None of the production techniques in use in semiconductor manufacturing can produce features with all these characteristics. In addition, requirements specified in the National Technology Roadmap for Semiconductors indicate that the width of the feature must be accurately calibrated to approximately 1-2 nm, a value well beyond the current capabilities of the instruments used for semiconductor metrology.
Date: September 21, 1999
Creator: ALLEN, RICHARD A.; CRESSWELL, MICHAEL W.; EVERIST, SARAH C.; GHOSHTAGORE, RATHINDRA N.; HEADLEY, THOMAS J. & LINHOLM, LOREN W.
Partner: UNT Libraries Government Documents Department

Reproducibility Data on SUMMiT

Description: SUMMiT (Sandia Ultra-planar Multi-level MEMS Technology) at the Sandia National Laboratories' MDL (Microelectronics Development Laboratory) is a standardized MEMS (Microelectromechanical Systems) technology that allows designers to fabricate concept prototypes. This technology provides four polysilicon layers plus three sacrificial oxide layers (with the third oxide layer being planarized) to enable fabrication of complex mechanical systems-on-a-chip. Quantified reproducibility of the SUMMiT process is important for process engineers as well as designers. Summary statistics for critical MEMS technology parameters such as film thickness, line width, and sheet resistance will be reported for the SUMMiT process. Additionally, data from Van der Pauw test structures will be presented. Data on film thickness, film uniformity and critical dimensions of etched line widths are collected from both process and monitor wafers during manufacturing using film thickness metrology tools and SEM tools. A standardized diagnostic module is included in each SWiT run to obtain post-processing parametric data to monitor run-to-run reproducibility such as Van der Pauw structures for measuring sheet resistance. This characterization of the SUMMiT process enables design for manufacturability in the SUMMiT technology.
Date: July 16, 1999
Creator: Irwin, Lloyd; Jakubczak, Jay; Limary, Siv; McBrayer, John; Montague, Stephen; Smith, James et al.
Partner: UNT Libraries Government Documents Department

Cosmic Evolution of Black Holes And Spheroids. 1, the M(BH)-Sigma Relation at Z=0.36

Description: We test the evolution of the correlation between black hole mass and bulge velocity dispersion (M{sub BH} - {sigma}), using a carefully selected sample of 14 Seyfert 1 galaxies at z = 0.36 {+-} 0.01. We measure velocity dispersion from stellar absorption lines around Mgb (5175 {angstrom}) and Fe (5270 {angstrom}) using high S/N Keck spectra, and estimate black hole mass from the H{beta} line width and the optical luminosity at 5100 {angstrom}, based on the empirically calibrated photo-ionization method. We find a significant offset from the local relation, in the sense that velocity dispersions were smaller for given black hole masses at z = 0.36 than locally. We investigate various sources of systematic uncertainties and find that those cannot account for the observed offset. The measured offset is {Delta} log M{sub BH} = 0.62 {+-} 0.10 {+-} 0.25, i.e. {Delta} log {sigma} = 0.15 {+-} 0.03 {+-} 0.06, where the error bars include a random component and an upper limit to the systematics. At face value, this result implies a substantial growth of bulges in the last 4 Gyr, assuming that the local M{sub BH} - {sigma} relation is the universal evolutionary end-point. Along with two samples of active galaxies with consistently determined black hole mass and stellar velocity dispersion taken from the literature, we quantify the observed evolution with the best fit linear relation, {Delta} log M{sub BH} = (1.66 {+-} 0.43)z + (0.04 {+-} 0.09) with respect to the local relationship of Tremaine et al. (2002), and {Delta} log M{sub BH} = (1.55 {+-} 0.46)z +(0.01 {+-} 0.12) with respect to that of Ferrarese (2002). This result is consistent with the growth of black holes predating the final growth of bulges at these mass scales (<{sigma}> = 170 km s{sup -1}).
Date: April 17, 2006
Creator: Woo, Jong-Hak; Treu, Tommaso; /UC, Santa Barbara; Malkan, Matthew A.; /UCLA; Blandford, Roger D. et al.
Partner: UNT Libraries Government Documents Department

SUCCESSFUL BUNCHED BEAM STOCHASTIC COOLING IN RHIC.

Description: We report on a successful test of bunch-beam stochastic cooling in RHIC at 100 GeV. The cooling system is designed for heavy ions but was tested in the recent RHIC run which operated only with polarized protons. To make an analog of the ion beam a special bunch was prepared with very low intensity. This bunch had {approx}1.5 x 10{sup 9} protons, while the other 100 bunches contained {approx}1.2 x 10{sup 11} protons each. With this bunch a cooling time on the order 1 hour was observed through shortening of the bunch length and increase in the peak bunch current, together with a narrowing of the spectral line width of the Scottky power at 4 GHz. The low level signal processing electronics and the isolated-frequency kicker cavities are described.
Date: June 23, 2006
Creator: BRENNAN, J.M.; BLASKIEWICZ, M. & SEVERINO, F.
Partner: UNT Libraries Government Documents Department

Fermi Surface and Van Hove Singularities in the Itinerant Metamagnet Sr(3)Ru(2)O(7)

Description: The low-energy electronic structure of the itinerant metamagnet Sr{sub 3}Ru{sub 2}O{sub 7} is investigated by angle resolved photoemission and density functional calculations. We find well-defined quasiparticle bands with resolution limited line widths and Fermi velocities up to an order of magnitude lower than in single layer Sr{sub 2}RuO{sub 4}. The complete topography, the cyclotron masses and the orbital character of the Fermi surface are determined, in agreement with bulk sensitive de Haas - van Alphen measurements. An analysis of the dxy band dispersion reveals a complex density of states with van Hove singularities (vHs) near the Fermi level; a situation which is favorable for magnetic instabilities.
Date: January 4, 2011
Creator: Tamai, A.; Allan, M. P.; Mercure, J. F.; Meevasana, W.; Dunkel, R.; Lu, D. H. et al.
Partner: UNT Libraries Government Documents Department

Performance of actinic EUVL mask imaging using a zoneplate microscope

Description: The SEMATECH Berkeley Actinic Inspection Tool (AIT) is a dual-mode, scanning and imaging extreme-ultraviolet (EUV) microscope designed for pre-commercial EUV mask research. Dramatic improvements in image quality have been made by the replacement of several critical optical elements, and the introduction of scanning illumination to improve uniformity and contrast. We report high quality actinic EUV mask imaging with resolutions as low as 100-nm half-pitch, (20-nm, 5x wafer equivalent size), and an assessment of the imaging performance based on several metrics. Modulation transfer function (MTF) measurements show high contrast imaging for features sizes close to the diffraction-limit. An investigation of the illumination coherence shows that AIT imaging is much more coherent than previously anticipated, with {sigma} below 0.2. Flare measurements with several line-widths show a flare contribution on the order of 2-3% relative intensity in dark regions above the 1.3% absorber reflectivity on the test mask used for these experiments. Astigmatism coupled with focal plane tilt are the dominant aberrations we have observed. The AIT routinely records 250-350 high-quality images in numerous through-focus series per 8-hour shift. Typical exposure times range from 0.5 seconds during alignment, to approximately 20 seconds for high-resolution images.
Date: September 25, 2007
Creator: Goldberg, K; Naulleau, P; Barty, A; Rekawa, S; Kemp, C; Gunion, R et al.
Partner: UNT Libraries Government Documents Department

Clamping of the Linewidth Enhancement Factor in Narrow Quantum-Well GRINSCH Semiconductor Lasers

Description: The linewidth enhancement factor in single quantum-well GRINSCH semiconductor lasers is investigated theoretically and experimentally. For thin wells a small linewidth enhancement factor is obtained which clamps with increasing carrier density, in contrast to the monotonous increase observed for thicker wells. Microscopic many-body calculations reproduce the experimental observations attributing the clamping to a subtle interplay between excitation dependent gain shifts and carrier population distributions.
Date: January 20, 1999
Creator: Bossert, D.; Chow, W.W.; Hader, J.; Koch, S.W.; Moloney, J.V. & Stohls, J.
Partner: UNT Libraries Government Documents Department

ESR studies of two new organic superconductors: {beta}``-(BEDT-TTF){sub 2}SF{sub 5}CH{sub 2}CF{sub 2}SO{sub 3} and {kappa}{sub L}`-(BEDT-TTF){sub 2}Cu(CF{sub 3}){sub 4}(DBCE)

Description: The normal-state ESR of two new organic superconductors, {beta}{double_prime}-(BEDT-TTF){sub 2}SF{sub 5}CH{sub 2}CF{sub 2}SO{sub 3} and {kappa}{sub L}{prime}-(BEDT-TTF){sub 2}Cu(CF{sub 3}){sub 4}(DBCE) are reported. Both compounds showed metallic properties below 140 K. The former gave ESR line widths and g-values of 23-34 G and 2.004-2.012. The latter gave line widths and g-values of 45-58 G and 2.006-2.012. Orientation-dependent line widths and g-values of the {kappa}{sub L}{prime}-phase were found to be similar to that of the {kappa}-(ET){sub 4}Hg{sub 3}Br{sub 8} but not to the {kappa}{sub L}-phases in general.
Date: October 1, 1996
Creator: Wang, H.H.; VanZile, M.L. & Geiser, U.
Partner: UNT Libraries Government Documents Department

Stress Voiding During Wafer Processing

Description: Wafer processing involves several heating cycles to temperatures as high as 400 C. These thermal excursions are known to cause growth of voids that limit reliability of parts cut from the wafer. A model for void growth is constructed that can simulate the effect of these thermal cycles on void growth. The model is solved for typical process steps and the kinetics and extent of void growth are determined for each. It is shown that grain size, void spacing, and conductor line width are very important in determining void and stress behavior. For small grain sizes, stress relaxation can be rapid and can lead to void shrinkage during subsequent heating cycles. The effect of rapid quenching from process temperatures is to suppress void growth but induce large remnant stress in the conductor line. This stress can provide the driving force for void growth during storage even at room temperature. For isothermal processes the model can be solved analytically and estimates of terminal void size a nd lifetime are obtained.
Date: March 1, 1999
Creator: Yost, F.G.
Partner: UNT Libraries Government Documents Department

Progress in the fabrication of high aspect ratio zone plates by soft x-ray lithography.

Description: Soft x-ray lithography technology has been applied to fabrication of phase shifting Fresnel Zone Plate (FZP's) for hard x-rays. Effects of the exposure conditions, developing system, and electroplating process parameters on line width and aspect ratio have been analyzed. The process has been optimized and an aspect ratio of 11 has been achieved for 110 nm outermost zone width. SEM and AFM have been used for preliminary metrology of the FZPs. The FZP optical performance was characterized at 8 keV photon energy at the 2-ID-D beam line at the Advanced Photon Source. Focusing efficiencies of 23% for FZPs apertures to 100 microns and 18% for 150-micron-diameter apertures have been obtained. The parameters of the fabricated FZP are in good agreement with the predicted values.
Date: August 13, 2002
Creator: Divan, R.; Mancini, D. C.; Moldovan, N. A.; Lai, B.; Assoufid, L.; Leondard, Q. et al.
Partner: UNT Libraries Government Documents Department

Effect of the slit widths. Appendix A

Description: The aim of this mathematical treatment is to prove that any distortion of the gaussian intensity distribution of the beam, which may be caused by the finite width of the slits, is small, provided that the slit widths are not large with respect to the source size and divergence. The widths of the slit A and of the slit B were the same, equal to 0.1 mm for the measurement of the horizontal source size and divergence, and equal to 0.025 mm in the vertical case. It turns out, as shown below, that the distortion of the phase space gaussian beam distribution is estimated to be not greater than 6% in the vertical case and is considerably smaller in the horizontal case. The procedure followed in the analysis of the experimental data is then justified and is a good approximation.
Date: December 31, 1990
Partner: UNT Libraries Government Documents Department

Large Scale Nanolaminate Deformable Mirror

Description: This work concerns the development of a technology that uses Nanolaminate foils to form light-weight, deformable mirrors that are scalable over a wide range of mirror sizes. While MEMS-based deformable mirrors and spatial light modulators have considerably reduced the cost and increased the capabilities of adaptive optic systems, there has not been a way to utilize the advantages of lithography and batch-fabrication to produce large-scale deformable mirrors. This technology is made scalable by using fabrication techniques and lithography that are not limited to the sizes of conventional MEMS devices. Like many MEMS devices, these mirrors use parallel plate electrostatic actuators. This technology replicates that functionality by suspending a horizontal piece of nanolaminate foil over an electrode by electroplated nickel posts. This actuator is attached, with another post, to another nanolaminate foil that acts as the mirror surface. Most MEMS devices are produced with integrated circuit lithography techniques that are capable of very small line widths, but are not scalable to large sizes. This technology is very tolerant of lithography errors and can use coarser, printed circuit board lithography techniques that can be scaled to very large sizes. These mirrors use small, lithographically defined actuators and thin nanolaminate foils allowing them to produce deformations over a large area while minimizing weight. This paper will describe a staged program to develop this technology. First-principles models were developed to determine design parameters. Three stages of fabrication will be described starting with a 3 x 3 device using conventional metal foils and epoxy to a 10-across all-metal device with nanolaminate mirror surfaces.
Date: November 30, 2005
Creator: Papavasiliou, A; Olivier, S; Barbee, T; Miles, R & Chang, K
Partner: UNT Libraries Government Documents Department

The Suzaku Observation of the Nucleus of theRadio-Loud Active Galaxy Centaurus A: Constraints on Abundances of the Accreting Material

Description: A Suzaku observation of the nucleus of the radio-loud AGN Centaurus A in 2005 has yielded a broadband spectrum spanning 0.3 to 250 keV. The net exposure times after screening were: 70 ks per X-ray Imaging Spectrometer (XIS) camera, 60.8 ks for the Hard X-ray Detector (HXD) PIN, and 17.1 ks for the HXD-GSO. The hard X-rays are fit by two power-laws of the same slope, absorbed by columns of 1.5 and 7 x 10{sup 23} cm{sup -2} respectively. The spectrum is consistent with previous suggestions that the power-law components are X-ray emission from the sub-pc VLBI jet and from Bondi accretion at the core, but it is also consistent with a partial covering interpretation. The soft band is dominated by thermal emission from the diffuse plasma and is fit well by a two-temperature vapec model, plus a third power-law component to account for scattered nuclear emission, jet emission, and emission from X-ray Binaries and other point sources. Narrow fluorescent emission lines from Fe, Si, S, Ar, Ca and Ni are detected. The Fe K{alpha} line width yields a 200 light-day lower limit on the distance from the black hole to the line-emitting gas. Fe, Ca, and S K-shell absorption edges are detected. Elemental abundances are constrained via absorption edge depths and strengths of the fluorescent and diffuse plasma emission lines. The high metallicity ([Fe/H]=+0.1) of the circumnuclear material suggests that it could not have originated in the relatively metal-poor outer halo unless enrichment by local star formation has occurred. Relative abundances are consistent with enrichment from Type II and Ia supernovae.
Date: June 27, 2007
Creator: Markowitz, A.; Takahashi, T.; Watanabe, S.; Nakazawa, K.; Fukazawa, Y.; Kokubun, M. et al.
Partner: UNT Libraries Government Documents Department

Discovery of a GeV Blazar Shining Through the Galactic Plane

Description: The Fermi Large Area Telescope (LAT) discovered a new gamma-ray source near the Galactic plane, Fermi J0109+6134, when it flared brightly in 2010 February. The low Galactic latitude (b = -1.2{sup o}) indicated that the source could be located within the Galaxy, which motivated rapid multi-wavelength follow-up including radio, optical, and X-ray observations. We report the results of analyzing all 19 months of LAT data for the source, and of X-ray observations with both Swift and the Chandra X-ray Observatory. We determined the source redshift, z = 0.783, using a Keck LRIS observation. Finally, we compiled a broadband spectral energy distribution (SED) from both historical and new observations contemporaneous with the 2010 February flare. The redshift, SED, optical line width, X-ray obsorption, and multi-band variability indicate that this new Gev source is a blazar seen through the Galactic plane. Because several of the optical emission lines have equivalent width > 5 {angstrom}, this blazar belongs in the flat-spectrum radio quasar category.
Date: August 11, 2011
Creator: Vandenbroucke, J.; Buehler, R.; Ajello, M.; Bechtol, K.; Bellini, A.; Bolte, M. et al.
Partner: UNT Libraries Government Documents Department