A5018079266- Astrophysics and Cosmic Phenomena
- Gamma-ray bursts and supernovae
- Dark Matter and Cosmic Phenomena
- Atmospheric Ozone and Climate
- Pulsars and Gravitational Waves Research
- Atmospheric and Environmental Gas Dynamics
- Radio Astronomy Observations and Technology
- Astrophysical Phenomena and Observations
- Atmospheric chemistry and aerosols
- Atmospheric aerosols and clouds
- Spectroscopy and Laser Applications
- Particle Detector Development and Performance
- Galaxies: Formation, Evolution, Phenomena
- Neutrino Physics Research
- Solar and Space Plasma Dynamics
- Particle physics theoretical and experimental studies
- Cosmology and Gravitation Theories
- Astronomical Observations and Instrumentation
- Advanced X-ray Imaging Techniques
- Methane Hydrates and Related Phenomena
- Aquatic and Environmental Studies
- Advanced X-ray and CT Imaging
- Molecular Spectroscopy and Structure
- Black Holes and Theoretical Physics
- Laser Design and Applications
V.E. Zuev Institute of Atmospheric Optics
2012-2023
Russian Academy of Sciences
2010-2023
National Research Tomsk State University
2018-2019
George Mason University
2009-2013
United States Naval Research Laboratory
2009-2013
A young and energetic pulsar powers the well-known Crab Nebula. Here, we describe two separate gamma-ray (photon energy greater than 100 mega-electron volts) flares from this source detected by Large Area Telescope on board Fermi Gamma-ray Space Telescope. The first flare occurred in February 2009 lasted approximately 16 days. second was September 2010 4 During these outbursts, flux nebula increased factors of four six, respectively. brevity implies that gamma rays were emitted via...
This paper presents light curves as well the first systematic characterization of variability 106 objects in high-confidence Fermi Large Area Telescope Bright AGN Sample (LBAS). Weekly this sample, obtained during 11 months survey (2008 August 4–2009 July 4), are tested for and their properties quantified through autocorrelation function structure analysis. For brightest sources, 3 or 4 day binned extracted order to determine power density spectra (PDSs) fit temporal major flares. More than...
We report on the gamma-ray activity of high-synchrotron-peaked BL Lacertae object Mrk 421 during first 1.5 years Fermi operation, from 2008 August 5 to 2010 March 12. find that Large Area Telescope (LAT) spectrum above 0.3 GeV can be well-described by a power-law function with photon index Gamma=1.78 +/- 0.02 and average flux F(>0.3 GeV)=(7.23 0.16) x 10^{-8} ph cm^{-2} s^{-1}. Over this time period, Fermi-LAT was evaluated 7-day-long intervals, showing significant variations in (up factor...
Pulsars are rapidly-rotating, highly-magnetized neutron stars emitting radiation across the electromagnetic spectrum. Although there more than 1800 known radio pulsars, until recently, only seven were observed to pulse in gamma rays and these all discovered at other wavelengths. The Fermi Large Area Telescope makes it possible pinpoint through their gamma-ray pulsations. We report detection of 16 pulsars blind frequency searches using LAT. Most coincident with previously unidentified...
We report the discovery with Fermi/LAT of gamma-ray emission from three radio-loud narrow-line Seyfert 1 galaxies: PKS 1502+036 (z=0.409), 1H 0323+342 (z=0.061) and 2004-447 (z=0.24). In addition to PMN J0948+0022 (z=0.585), first source this type be detected in gamma rays, they may form an emerging new class active galactic nuclei (AGN). These findings can have strong implications on our knowledge about relativistic jets unified model AGN.
We present observations of the young supernova remnant (SNR) RX J1713.7−3946 with Fermi Large Area Telescope (LAT). clearly detect a source positionally coincident SNR. The is extended best-fit extension 055 ± 004 matching size non-thermal X-ray and TeV gamma-ray emission from remnant. positional coincidence allow us to identify LAT SNR J1713.7−3946. spectrum can be described by very hard power law photon index Γ = 1.5 0.1 that coincides in normalization steeper H.E.S.S.-detected at higher...
The discovery of bright gamma-ray emission coincident with supernova remnant (SNR) W51C is reported using the Large Area Telescope (LAT) on board Fermi Gamma-ray Space Telescope. a middle-aged (~10^4 yr) intense radio synchrotron in its shell and known to be interacting molecular cloud. spatially extended, broadly consistent X-ray extent SNR W51C. energy spectrum 0.2-50 GeV band exhibits steepening toward high energies. luminosity greater than 1x10^{36} erg/s given distance constraint D>5.5...
Microquasar Spotted Microquasars are binary star systems where a normal sheds matter onto neutron or black hole, generating x-ray radiation and jets of material moving at relativistic speeds. have proved difficult to detect in high-energy gamma rays (> 100 megaelectron volts). Using the Fermi Large Area Telescope, Abdo et al. (p. 1512 , published online 26 November; see Perspective by Bignami ) now report detection variable gamma-ray emission from microquasar Cygnus X-3. The flux is...
We report observation of the supernova remnant IC443 (G189.1+3.0) with Fermi Gamma-ray Space Telescope Large Area (LAT) in energy band between 200MeV and 50GeV. is a shell-type mixed morphology located off outer Galactic plane where high-energy emission has been detected X-ray, GeV TeV gamma-ray bands. Past observations suggest interacting surrounding interstellar matter. Proximity dense shocked molecular clouds GeV-TeV regions by EGRET, MAGIC VERITAS suggests an interpretation that...
We present precise phase-connected pulse timing solutions for 16 gamma-ray-selected pulsars recently discovered using the Large Area Telescope (LAT) on Fermi Gamma-ray Space plus one very faint radio pulsar (PSR J1124-5916) that is more effectively timed with LAT. describe analysis techniques including a maximum likelihood method determining times of arrival from unbinned photon data. A major result this work improved position determinations, which are crucial multi-wavelength follow up. For...
We report on the gamma-ray activity of blazar Mrk 501 during first 480 days Fermi operation. find that average LAT spectrum can be well described by a single power-law function with photon index 1.78 +/- 0.03. While we observe relatively mild flux variations Fermi-LAT (within less than factor 2), detect remarkable spectral variability where hardest observed within energy range is 1.52 0.14, and softest one 2.51 0.20. These unexpected changes do not correlate measured above 0.3GeV. In this...
The first published Fermi large area telescope (Fermi-LAT) measurement of the isotropic diffuse gamma-ray emission is in good agreement with a single power law, and not showing any signature dominant contribution from dark matter sources energy range 20 to 100 GeV. We use absolute size spectral shape this measured flux derive cross section limits on three types generic candidates: annihilating into quarks, charged leptons monochromatic photons. Predicted fluxes are strongly affected by...
We report on the observations of 14 dwarf spheroidal galaxies with Fermi Gamma-Ray Space Telescope taken during first 11 months survey mode operations. The telescope provides a new opportunity to test particle dark matter models through expected gamma-ray emission produced by pair annihilation weakly interacting massive particles (WIMPs). Local Group galaxies, largest galactic substructures predicted cold scenario, are attractive targets for such indirect searches because they nearby and...
We report the detection of high-energy gamma-ray emission from two starburst galaxies using data obtained with Large Area Telescope on board Fermi Gamma-ray Space Telescope. Steady point-like above 200 MeV has been detected at significance levels 6.8 sigma and 4.8 respectively, sources positionally coincident locations M82 NGC 253. The total fluxes are consistent originating interaction cosmic rays local interstellar gas radiation fields constitute evidence for a link between massive star...
The flat-spectrum radio quasar 3C 454.3 underwent an extraordinary 5-day gamma-ray outburst in November 2010 where the daily flux measured with Fermi Large Area Telescope (LAT) at photon energies E>100 MeV reached (66+/-2) x 10^-6 ph cm^-2 s^-1. This is a factor of 3 higher than its previous maximum recorded December 2009 and ~5 times brighter Vela pulsar, which normally brightest source sky. 3-hr peak was (85+/-5) s^-1, corresponding to apparent isotropic luminosity 2.1+/-0.2 10^50 erg...
This is the first of a series papers aimed at characterizing populations detected in high-latitude sky Fermi-LAT survey. In this work, we focus on intrinsic spectral and flux properties source sample. We show that when selection effects are properly taken into account, Fermi sources average steeper than previously found (e.g., bright list) with an photon index 2.40 ± 0.02 over entire 0.1–100 GeV energy band. confirm flat spectrum radio quasars have spectra BL Lacertae objects 2.48 versus...
Dark matter (DM) particle annihilation or decay can produce monochromatic γ rays readily distinguishable from astrophysical sources. γ-ray line limits 30 to 200 GeV obtained 11 months of Fermi Large Area Space Telescope data 20–300 are presented using a selection based on requirements for analysis, and integrated over most the sky. We obtain flux upper in range 0.6–4.5×10−9 cm−2 s−1, give corresponding DM cross-section lifetime limits. Theoretical implications briefly discussed.Received 19...
We present detailed analysis of two gamma-ray sources, 1FGL J1801.3−2322c and J1800.5−2359c, that have been found toward the supernova remnant (SNR) W28 with Large Area Telescope (LAT) on board Fermi Gamma-ray Space Telescope. is to be an extended source within boundary SNR W28, extensively overlap TeV HESS J1801−233, which associated a dense molecular cloud interacting SNR. The spectrum measured LAT from 0.2 100 GeV can described by broken power-law function break at ∼1 photon indices 2.09...
Nearby clusters and groups of galaxies are potentially bright sources high-energy gamma-ray emission resulting from the pair-annihilation dark matter particles. However, no significant has been detected so far in first 11 months observations with Fermi Large Area Telescope. We interpret this non-detection terms constraints on particle properties. In particular for leptonic annihilation final states masses greater than ~200 GeV, inverse Compton scattering CMB photons is expected to dominate...
The gamma-ray energy spectra of bright blazars the LAT Bright AGN Sample (LBAS) are investigated using Fermi-LAT data. Spectral properties (hardness, curvature, and variability) established a data set accumulated over 6 months operation presented discussed for different blazar classes subclasses: flat spectrum radio quasars (FSRQs), low-synchrotron peaked BLLacs (LSP-BLLacs), intermediate-synchrotron (ISP-BLLacs), high-synchrotron (HSP-BLLacs). distribution photon index (Γ, obtained from...
We present the analysis of interstellar gamma-ray emission measured by Fermi Large Area Telescope toward a region in second Galactic quadrant at 100 deg < l 145 and -15 b +30 deg. This encompasses prominent Gould-Belt clouds Cassiopeia, Cepheus Polaris flare, as well atomic molecular complexes larger distances, like that associated with NGC 7538 Perseus arm. The good kinematic separation velocity between local, Perseus, outer arms, presence massive each them make this suited to probe cosmic...
We report the discovery by Large Area Telescope (LAT) onboard Fermi Gamma-ray Space of high-energy gamma-ray emission from peculiar quasar PMN J0948+0022 (z=0.5846). The optical spectrum this object exhibits rather narrow Hbeta (FWHM(Hbeta) ~ 1500 km s^-1), weak forbidden lines and is therefore classified as a narrow-line type I quasar. This class objects thought to have relatively small black hole mass accrete at high Eddington ratio. radio loudness variability compact core indicates...
We report the discovery of high-energy (E>100 MeV) gamma-ray emission from NGC 1275, a giant elliptical galaxy lying at center Perseus cluster galaxies, based on observations made with Large Area Telescope (LAT) Fermi Gamma ray Space Telescope. The positional source is only ~3' away 1275 nucleus, well within 95% LAT error circle ~5'.The spatial distribution photons consistent point source. average flux and power-law photon index measured 2008 August 4 to December 5 are F_gamma =...
We report on the first detection of GeV high-energy gamma-ray emission from a young supernova remnant with Large Area Telescope aboard Fermi Gamma-ray Space Telescope. These observations reveal source no discernible spatial extension detected at significance level 12.2$\sigma$ above 500 MeV location that is consistent position explosion occurred around 1680 in Cassiopeia constellation - A. The flux and spectral shape are scenario which originates relativistic particles accelerated shell this...
The diffuse Galactic gamma-ray emission is produced by cosmic rays (CRs) interacting with the interstellar gas and radiation field. Measurements Energetic Gamma-Ray Experiment Telescope (EGRET) instrument on Compton Observatory indicated excess > 1 GeV relative to models consistent directly measured CR spectra (the so-called ``EGRET excess''). was observed in all directions sky, a variety of explanations have been proposed, including beyond-the-Standard-Model scenarios like annihilating or...