Some evidence for large gravitational redshift in Seyfert galaxy NGC 4151

The photon spectra of two Seyfert galaxies NGC 4151 and MCG 8-11-11 are good experimentally established in the X-ray and gamma range. The annihilation of the high temperature positrons with cold electrons is proposed as the possible mechanism of photon production in the Seyfert galaxy NGC 4151. The photon spectrum of NGC 4151 with its observed features from the soft X to the gamma ray range is described by annihilation of positrons and electrons at temperatures 3 x 10 to the 12th power K and 10 to the 8th power K respectively. The photon spectra from annihilation of unthermalized plasma with above parameters should be shifted to the lower energy by redshift z = 100. In that case the source of photons should be placed closely to the black hole horizon (r approximately equal to 1.0001 r sub g

Unthermalized positrons in gamma ray burst sources

The spectra of the broadening 0.511 MeV annihilation line produced by high temperatures was calculated in the case of unthermalized plasma; i.e., T sub e(+) is not = T sub e(-). The flattening in the spectrum of the annihilation lines for large differences of electron and positron temperatures is a strong indication that the observed features of the hard tailed spectrum of the gamma bursts can be well described by annihilation of unthermalized positrons. It is proposed that the charge separation occurring in Eddington limited accretion onto a neutron star or the one photon pair production in strong magnetic fields as a mechanism for the production of unthermalized positrons in the sources of gamma bursts. From the best fit of experimental spectra by the model, the parameters of sources for which the regions with different plasma temperatures can exist is evaluated

Virgo cluster as a high energy cosmic rays source

The extragalactic charged particles are reflecting from the Galaxy by its magnetic field. Assuming magnetic field in the Galaxy as quasilongitudinal, the mean transparency of Galaxy has been evaluated for extragalactic protons defined as a fraction of particles at a given energy from a given direction passing by the galactic plane. The anisotropy caused by the Galactic magnetic field reflection of protons can explain observed arrival directions of extensive air showers at large angle to the galactic plane. Our analysis shows that the increase with energy observed in sin b sup 11 is self-consistent with changing in the cosmic ray energy spectrum at high energy (E 10 to the 19th power eV) in the case when extragalactic cosmic ray source with spectral index -2.2 is at the position of the Virgo Cluster

Unthermalized plasma in bursts sources

The pair e(+)-e(-) annihilation phenomena in hot plasma was studied in order to evaluate the photon energy spectrum. The spectra of the broadening 0.511 MeV annihilation line was calculated in the case of unthermalized plasma, i.e., T sub e(-) does not equal T sub e(+). The energy spectra from annihilation process for unthermalized positrons are characterized by the presence of flat part for energies greater than 0.511 MeV. The flattening in the spectrum of annihilation unthermalized plasma is a strong indication that the observed features of the hard tailed spectrum of the gamma bursts can be well described by annihilation of hot positrons and cold electrons. It is proposed that the mechanism for the production of unthermalized positrons is associated with the charge separation in Eddington limited accretion onto a neutron star

Some evidence for high energy gamma-ray sources at large galactic latitudes

The arrival directions of the gamma-quanta with energies of about 10 to 15th power eV which were registrated by Tien Shan experiment were compared with COS-B observations. On the basis of the Monte Carlo simulations it was shown with low probability that arrival directions of Tien Shan gamma-quanta initiated showers are not uniformly distributed. It is shown that in the region not seen by COS-B mission, the high energy gamma-ray sources should be located at position of 90 deg. 1 sup 11 130 deg and b sup 11 or = 50 deg. The integral intensity of these sources should be I ( 10 to the 15th power eV) = 4.8 + or - 1.7).10 to the 13th power/sq cm/s/str. There is no coincidence between the gamma-quanta registrated by Tien Shan experiment with Geminga intense COS-B gamma source. So it is shown that the integral photon spectrum of Geminga (I(e) approx E sup-Beta, where Beta = 0.8 for E 1 GeV) becomes steeper (Beta 1.2) in high energy region with probability 99.9.%

Lenslet array tunable snapshot imaging spectrometer (LATIS) for hyperspectral fluorescence microscopy

Snapshot hyperspectral imaging augments pixel dwell time and acquisition speeds over existing scanning systems, making it a powerful tool for fluorescence microscopy. While most snapshot systems contain fixed datacube parameters (x,y,λ), our novel snapshot system, called the lenslet array tunable snapshot imaging spectrometer (LATIS), demonstrates tuning its average spectral resolution from 22.66 nm (80x80x22) to 13.94 nm (88x88x46) over 485 to 660 nm. We also describe a fixed LATIS with a datacube of 200x200x27 for larger field-of-view (FOV) imaging. We report <1 sec exposure times and high resolution fluorescence imaging with minimal artifacts

Snapshot spectrally encoded fluorescence imaging through a fiber bundle

Fiber optic endomicroscopy is a valuable tool for clinical diagnostics and animal studies because it can capture images of tissue in vivo with subcellular resolution. Current configurations for endomicroscopes have either limited spatial resolution or require a scanning mechanism at the distal end of the fiber, which can slow imaging speed and increase the probe size. We present a novel configuration that provides high contrast 350 × 350 pixel images at 7.2 frames per second, without the need for mechanical scanning at the proximal or distal end of the fiber. The proofof- concept benchtop system is tested in fluorescence mode and can resolve 1.5 μm features of a high resolution 1951 USAF target

Real-time video mosaicing with a high-resolution microendoscope

Microendoscopes allow clinicians to view subcellular features in vivo and in real-time, but their field-of-view is inherently limited by the small size of the probe's distal end. Video mosaicing has emerged as an effective technique to increase the acquired image size. Current implementations are performed post-procedure, which removes the benefits of live imaging. In this manuscript we present an algorithm for real-time video mosaicing using a low-cost high-resolution microendoscope. We present algorithm execution times and show image results obtained from in vivo tissue