—The scanning Fabry–Perot interferometer (FPI) is the oldest method of optical 3D spectroscopy. It is still in use because of the high spectral resolution it provides over a large field of view. The ...history of the application of this method for the study of extended objects (nebulae and galaxies) and the technique of data reduction and analysis are discussed. The paper focuses on the performing observations with the scanning FPI on the 6-m telescope of the Special Astrophysical Observatory of the Russian Academy of Sciences. The instrument is currently used as a part of the SCORPIO-2 multimode focal reducer. The results of studies of various galactic and extragalactic objects with the scanning FPI on the 6-m telescope—star-forming regions and young stellar objects, spiral, ring, dwarf and interacting galaxies, gas subsystems associated with the ionization cones of active galactic nuclei, galactic winds, etc. are briefly discussed. Further prospects for research with the scanning FPI of the Special Astrophysical Observatory of the Russian Academy of Sciences are discussed.
Abstract
We seek to design experimentally feasible broadband, temporally multiplexed optical quantum memory with near-term applications to telecom bands. Specifically, we devise dispersion ...compensation (DC) for an impedance-matched narrow-band quantum memory by exploiting Raman processes over two three-level atomic subensembles, one for memory and the other for DC. DC provides impedance matching over more than a full cavity linewidth. Combined with 1 s spin-coherence lifetime the memory could be capable of power efficiency exceeding 90% leading to 10
6
modes for temporal multiplexing. Our design could lead to significant multiplexing enhancement for quantum repeaters to be used for telecom quantum networks.
We show that, under certain circumstances, an optical field in a two-mode squeezed vacuum (TMSV) state can propagate through a lossy atomic medium without degradation or evolution. Moreover, the ...losses give rise to that state when a different state is initially injected into the medium. Such a situation emerges in a Λ-type atomic system, in which both optical transitions are driven by strong laser fields that are two-photon resonant with the respective signal modes. Then the interactions of the two signal modes with the ground-state atomic coherence interfere destructively, thereby ensuring the preservation of the TMSV with a particular squeezing parameter. This mechanism permits unified interpretation of recent experimental results and predicts new phenomena.
Star formation driven galactic winds in UGC 10043 López-Cobá, C; Sánchez, S. F; Moiseev, A. V ...
Monthly Notices of the Royal Astronomical Society,
06/2017, Letnik:
467, Številka:
4
Journal Article
Recenzirano
Odprti dostop
Abstract
We study the galactic wind in the edge-on spiral galaxy UGC 10043 with the combination of the CALIFA integral field spectroscopy data, scanning Fabry–Perot interferometry (FPI) and multiband ...photometry. We detect ionized gas in the extraplanar regions reaching a relatively high distance, up to ∼4 kpc above the galactic disc. The ionized gas line ratios (N ii/Hα, S ii/Hα and O i/Hα) present an enhancement along the semiminor axis, in contrast with the values found at the disc, where they are compatible with ionization due to H ii-regions. These differences, together with the biconic symmetry of the extra-planar ionized structure, make UGC 10043 a clear candidate for a galaxy with gas outflows ionizated by shocks. From the comparison of shock models with the observed line ratios, and the kinematics observed from the FPI data, we constrain the physical properties of the observed outflow. The data are compatible with a velocity increase of the gas along the extraplanar distances up to <400 km s−1 and the pre-shock density decreasing in the same direction. We also observe a discrepancy in the SFR estimated based on Hα (0.36 M⊙ yr−1) and that estimated with the cigale code, the latter being five times larger. Nevertheless, this SFR is still not enough to drive the observed galactic wind if we do not take into account the filling factor. We stress that the combination of the three techniques of observation with the models is a powerful tool to explore galactic winds in the Local Universe.
We study the evolution of qubits amplitudes in a one-dimensional chain consisting of three equidistantly spaced noninteracting qubits embedded in an open waveguide. The study is performed in the ...frame of single-excitation subspace, where the only qubit in the chain is initially excited. We show that the dynamics of qubits amplitudes crucially depend on the value of
kd
, where
k
is the wave vector and
d
is a distance between neighbor qubits. If
kd
is equal to an integer multiple of
π
, then the qubits are excited to a stationary level. In this case, it is the dark states which prevent qubits from decaying to zero, even though they do not contribute to the output spectrum of photon emission. For other values of
kd
, the excitations of qubits exhibit the damping oscillations which represent the vacuum Rabi oscillations in a three-qubit system. In this case, the output spectrum of photon radiation is determined by a subradiant state which has the lowest decay rate. We also investigated the case with the frequency of a central qubit being different from that of the edge qubits. In this case, the qubits’ decay rates can be controlled by the frequency detuning between the central and the edge qubits.
We measured separate cosmic-ray electron and positron spectra with the Fermi Large Area Telescope. Because the instrument does not have an onboard magnet, we distinguish the two species by exploiting ...Earth's shadow, which is offset in opposite directions for opposite charges due to Earth's magnetic field. We estimate and subtract the cosmic-ray proton background using two different methods that produce consistent results. We report the electron-only spectrum, the positron-only spectrum, and the positron fraction between 20 and 200 GeV. We confirm that the fraction rises with energy in the 20-100 GeV range. The three new spectral points between 100 and 200 GeV are consistent with a fraction that is continuing to rise with energy.
The dwarf spheroidal satellite galaxies (dSphs) of the Milky Way are some of the most dark matter (DM) dominated objects known. We report on γ-ray observations of Milky Way dSphs based on six years ...of Fermi Large Area Telescope data processed with the new Pass8 event-level analysis. None of the dSphs are significantly detected in γ rays, and we present upper limits on the DM annihilation cross section from a combined analysis of 15 dSphs. These constraints are among the strongest and most robust to date and lie below the canonical thermal relic cross section for DM of mass ≲100 GeV annihilating via quark and τ-lepton channels.
In this paper, we present the analysis and results of a direct measurement of the cosmic-ray proton spectrum with the CALET instrument onboard the International Space Station, including the detailed ...assessment of systematic uncertainties. The observation period used in this analysis is from October 13, 2015 to August 31, 2018 (1054 days). We have achieved the very wide energy range necessary to carry out measurements of the spectrum from 50 GeV to 10 TeV covering, for the first time in space, with a single instrument the whole energy interval previously investigated in most cases in separate subranges by magnetic spectrometers (BESS-TeV, PAMELA, and AMS-02) and calorimetric instruments (ATIC, CREAM, and NUCLEON). The observed spectrum is consistent with AMS-02 but extends to nearly an order of magnitude higher energy, showing a very smooth transition of the power-law spectral index from -2.81±0.03 (50-500 GeV) neglecting solar modulation effects (or -2.87±0.06 including solar modulation effects in the lower energy region) to -2.56±0.04 (1-10 TeV), thereby confirming the existence of spectral hardening and providing evidence of a deviation from a single power law by more than 3σ.
Extended results on the cosmic-ray electron + positron spectrum from 11 GeV to 4.8 TeV are presented based on observations with the Calorimetric Electron Telescope (CALET) on the International Space ...Station utilizing the data up to November 2017. The analysis uses the full detector acceptance at high energies, approximately doubling the statistics compared to the previous result. CALET is an all-calorimetric instrument with a total thickness of 30 X_{0} at normal incidence and fine imaging capability, designed to achieve large proton rejection and excellent energy resolution well into the TeV energy region. The observed energy spectrum in the region below 1 TeV shows good agreement with Alpha Magnetic Spectrometer (AMS-02) data. In the energy region below ∼300 GeV, CALET's spectral index is found to be consistent with the AMS-02, Fermi Large Area Telescope (Fermi-LAT), and Dark Matter Particle Explorer (DAMPE), while from 300 to 600 GeV the spectrum is significantly softer than the spectra from the latter two experiments. The absolute flux of CALET is consistent with other experiments at around a few tens of GeV. However, it is lower than those of DAMPE and Fermi-LAT with the difference increasing up to several hundred GeV. The observed energy spectrum above ∼1 TeV suggests a flux suppression consistent within the errors with the results of DAMPE, while CALET does not observe any significant evidence for a narrow spectral feature in the energy region around 1.4 TeV. Our measured all-electron flux, including statistical errors and a detailed breakdown of the systematic errors, is tabulated in the Supplemental Material in order to allow more refined spectral analyses based on our data.
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