نتایج جستجو برای: spectrum lines
تعداد نتایج: 433909 فیلتر نتایج به سال:
We apply ideas that have appeared in the study of D-branes on Calabi-Yau compactifications to the derivation of the BPS spectrum of field theories. In particular, we identify an orbifold point whose fractional branes can be thought of as “partons” of the BPS spectrum of N = 2 pure SU(N) SYM. We derive the BPS spectrum and lines of marginal stability branes near that orbifold, and compare our re...
We present the 2.4−45 μm ISO-SWS spectrum of the Be star γ Cas (B0.5 IVe). The spectrum is characterised by a thermal continuum which can be well fit by a powerlaw Sν ∝ ν0.99 over the entire SWS wavelength range. For an isothermal disc of ionized gas with constant opening angle, this correponds to a density gradient ρ(r) ∝ r−2.8. We report the detection of the Humphreys (6-∞) bound-free jump in...
We present a Hubble Space Telescope Space Telescope Imaging Spectrograph spectrum of ASASSN-14li, the first rest-frame ultraviolet (UV) spectrum of a tidal disruption flare (TDF). The underlying continuum is well fit by a blackbody with T 3.5 10 UV 4 = ́ K, an order of magnitude smaller than the temperature inferred from X-ray spectra (and significantly more precise than previous efforts based ...
We present infrared (IR) and optical echelle spectra of the Classical T Tauri star TW Hydrae. Using the optical data, we perform detailed spectrum synthesis to fit atomic and molecular absorption lines and determine key stellar parameters: Teff = 4126± 24 K, log g = 4.84± 0.16, [M/H]= −0.10± 0.12, v sin i = 5.8± 0.6 km s. The IR spectrum is used to look for Zeeman broadening of photospheric abs...
We present a first analysis of a high resolution X-ray spectrum of the ionized stellar wind of Vela X-1 during eclipse. The data were obtained with the High Energy Transmission Grating Spectrometer onboard the Chandra X-ray Observatory. The spectrum is resolved into emission lines with fluxes between 0.02 and 1.04×10−4 photons cm−2s−1. We identify lines from a variety of charge states, includin...
We report on high-resolution observations (ℜ ≃ 45000) of the Hubble Deep Field South QSO J2233-606 obtained with the VLT UV-Visual Echelle Spectrograph (UVES). We present spectral data for the wavelength region 3050 < λ < 10000Å. The S/N ratio of the final spectrum is about 50 per resolution element at 4000Å, 90 at 5000Å, 80 at 6000Å, 40 at 8000Å. Redshifts, column densities and Doppler widths ...
The solar EUV irradiance is a key input for thermospheric and ionospheric models. Difficulties in continuously measuring the calibrated spectrum has prompted the use of various surrogate quantities. Although most proxies correlate quite well with the spectral variability, their use for modelling purposes becomes increasingly unsatisfactory. A different and data-driven approach is considered her...
Analysis of the hot H2 16O spectrum, presented by Polyansky et al. (1996, J. Mol. Spectrosc. 176, 305-315), is extended to higher vibrational states. Three hundred thirty mainly strong lines are assigned to pure rotational transitions in the (100), (001), and (020) vibrational states. These lines, which involve significantly higher rotational energy levels than were known previously, are assign...
We present an XMM-Newton spectrum of diffuse X-ray emission from within the solar system. The spectrum is dominated by probable C VI lines at 0.37 keV and 0.46 keV, an O VII line at 0.56 keV, O VIII lines at 0.65 keV and ∼ 0.8 keV, Ne IX lines at ∼ 0.92 keV, and Mg XI lines at ∼ 1.35 keV. This spectrum is consistent with that expected from charge exchange emission between the highly ionized sol...
We present JHK photometry and spectroscopy of RX J0019.8+2156. The spectrum appears to be dominated by the accretion disc to at least 2.4 μm, over any other source of emission. We find Paschen, Brackett and He II lines strongly in emission, but no He I. There are satellite lines approximately 850km s either side of the strongest, unblended hydrogen lines. These satellite lines may be the spectr...
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