相关论文: Complex Velocity Fields in the Shell of T Pyxidis
We report the radio detection of a shell-like HI structure in proximity to, and probably associated with, the nova V458 Vul. High spectral resolution observation with the Giant Metrewave Radio Telescope has made it possible to study the…
The results from deep long-slit spectroscopy of nine edge-on spiral galaxies with known extraplanar line emission are reported. Emission from Halpha, [N II] lambda 6548, 6583, and [S II] lambda 6716, 6731 is detected out to heights of a few…
(abridged abstract) We present multi-epoch high-resolution spectroscopy and photoelectric polarimetry of the long-period polar (AM Herculis star) QQ Vul. The blue emission lines show several distinct components, the sharpest of which can…
We present a spectrum of the symbiotic star V1016 Cyg observed with the 3.6 m Canada-France-Hawaii Telescope, in order to illustrate a method to measure the covering factor of the neutral scattering region around the giant component with…
Optical emission lines have now been detected from about 20 high velocity clouds. These emission lines -- primarily H-alpha, secondarily [N II] and [S II] -- are very faint and diffuse, spread over the surfaces of the clouds. We compile…
Disks around T Tauri stars are known to lose mass, as best shown by the profiles of forbidden emission lines of low ionization species. At least two separate kinematic components have been identified, one characterised by velocity shifts of…
Powerful astronomical spectra reveal an urgent need for additional work on atomic lines, levels, and oscillator strengths. The star HD 65949 provides some excellent examples of species rarely identified in stellar spectra. For example, the…
We present spectra taken with the Low Resolution Imaging Spectrograph on the Keck 10m telescope of spatially-resolved structures ("fuzz") around the high-redshift radio-loud quasars PKS 0445+097 (z=2.108) and PKS 2338+042 (z=2.589). For PKS…
Very sensitive HI 21cm observations have been made in 860 directions at dec >= -43deg in search of weak, Galactic, high-velocity HI emission lines at moderate and high Galactic latitudes. One-third of the observations were made toward…
We report deep long-slit emission-line spectra, the line flux ratios, and Doppler profile shapes of various bright optical lines. The low-ionization lines (primarily [N I], [O I], [S II], and [N II]) originate in shocked knots, as reported…
Spectra that cover 0.63 - 0.69um with a spectral resolution ~ 17000 are presented of the W Serpentis system V367 Cygni. Absorption lines of FeII and SiII that form in a circumsystem shell are prominent features, and the depths of these are…
A strong emission line at 2.8935 mu discovered by Rubin et al. (2001) in an ISO SWS02 spectrum of the Orion Nebula is identified as the 4p - 4s multiplet of the O I triplets. Line formation is due to de-excitation cascades following…
The brightest galaxy in the nearby Perseus cluster, NGC1275, is surrounded by a network of filaments. These were first observed through their Halpha emission but are now known to have a large molecular component with a total mass…
The strongest absorption features with the lower-level excitation potentials $\chi_{\rm low}<1$ eV are found to be split in the high-resolution optical spectra of the post-AGB star V354 Lac taken in 2007--2008. Main parameters,…
Recurrent nova (RN) T Pyxidis (T Pyx) has a complex history of mass accreting-onto and ejection-from the white dwarf, with a classical nova eruption around 1866 kick-starting a RN-phase with six RN eruptions from 1890--2011. T Pyx is a…
Nova V5856 Sagittarii is unique for having remained more than nine magnitudes above its pre-outburst brightness for more than six years. Extensive visible and IR spectra from the time of outburst to the present epoch reveal separate…
Despite being the prototype of its class, T Pyx is arguably the most unusual and poorly understood recurrent nova. Here, we use radio observations from the Karl G. Jansky Very Large Array to trace the evolution of the ejecta over the course…
We present H-alpha velocity fields of thirteen giant H II regions in four nearby dwarf irregular galaxies, NGC 2366, Holmberg II, IC 2574, and WLM. We classify the velocity features as well as the morphologies of the H II regions. The…
We study the spectroscopic and ionized structural evolution of T Pyx during its 2011 outburst, and also study the variation in degree of polarization during its early phase. Optical spectroscopic data of this system obtained from day…
We present new narrow-band filter imagery in H-alpha and [N II] 6584 along with UV and optical spectrophotometry measurements from 1200 to 9600 Angstroms of NGC 7293, the Helix Nebula, a nearby, photogenic planetary nebula of large diameter…