相关论文: Scattered Nuclear Continuum and Broad H-alpha in C…
High quality 4500-6800 A spectropolarimetric observations of the Circinus galaxy are reported. These show polarized and relatively broad (FWHM~3300 km/s) Halpha (as well as marginal Hbeta) arising from a <3" (<60 pc) region centered on the…
Optical spectropolarimetry of the nucleus of the LINER NGC 1052, obtained at the Keck Observatory, reveals a rise in polarization in the wings of the H-alpha line profile. The polarization vector of H-alpha is offset by 67 degrees from the…
Raman scattering by atomic hydrogen converts the UV continuum around Ly$\beta$ into optical continuum around H$\alpha$, and the basic atomic physics has been discussed in several works on symbiotic stars. We propose that the same process…
Centaurus A (Cen A) is the closest radio galaxy and a prime example of a low-luminosity active galactic nucleus (AGN), exhibiting complex emissions across the electromagnetic spectrum. The nature of its continuum emission, particularly the…
We report results from HST/NICMOS 2 micron imaging polarimetry of the central region of Centaurus A. In the vicinity of the nucleus we observe a complex polarization structure which we explain by a combination of scattering of nuclear light…
We present near-IR imaging polarimetry observations of the nucleus of Cygnus A, taken with the NICMOS camera of the HST at a wavelength of 2.0 microns.These maps reveal a highly collimated region of polarized emission straddling the nucleus…
We report the detection of linearly polarized emission at 53 and 89 $\mu$m, from the radio-loud active galactic nucleus (AGN) Cygnus A using HAWC+ onboard SOFIA. We measure a highly polarized core of $11\pm3$% and $9\pm2$% with a position…
We detail the spectral analysis of a 170 ks XRISM Resolve observation of the core of Cygnus A. The high spectral resolution of Resolve have enabled us to probe the inner accretion region of Cygnus A by analyzing the 6.4 keV Fe K$\alpha$…
From optical spectropolarimetry of Cygnus A we conclude that the scattering medium in the ionization cones in Cygnus A is moving outward at a speed of 170+-34 km/s, and that the required momentum can be supplied by the radiation pressure of…
We report Chandra ACIS and quasi-simultaneous RXTE observations of the nearby, powerful radio galaxy Cygnus A, with the present paper focusing on the properties of the active nucleus. In the Chandra observation, the hard (> a few keV) X-ray…
We present Monte Carlo simulations of the Diffuse H$\alpha$ Galactic Background. Our models comprise direct and multiply scattered H$\alpha$ radiation from the kpc scaleheight Warm Ionized Medium and midplane H II regions. The scattering is…
We present J, H and K-band spectroscopy of Cygnus A, spanning 1.0-2.4 micron in the rest-frame and hence several rovibrational H2, H recombination and [FeII] emission lines. The lines are spatially extended by up to 6kpc from the nucleus,…
Powered by a supermassive black hole with an accretion disk, the spectra of active galactic nuclei (AGNs) are characterized by prominent emission lines including Balmer lines. The unification schemes of AGNs require the existence of a thick…
We describe the results of a detailed study of the polarization properties of the broad H-alpha emission line in Type 1 Seyfert nuclei. Our analysis of these data points to a model in which the broad Balmer lines are emitted by a rotating…
We use Gemini Near-Infrared Integral Field Spectrograph (NIFS) observations of the inner 3.5$\times$3.5 kpc$^2$ of the radio galaxy Cygnus A to map the gas excitation and kinematics at a spatial resolution of 200 pc. The emission of the…
We present subarcsecond resolution mid-infrared images at 10.8 and 18.2 microns of Cygnus A. These images were obtained with the University of Florida mid-IR camera/spectrometer OSCIR at the Keck II 10-m telescope. Our data show extended…
We present 1420 MHz (lambda=21cm) observations of polarized emission from an area of 117 degree square in the Galactic plane in Cygnus, covering 82 < l < 95, -3.5 < b < +5.5, a complex region where the line of sight is directed nearly along…
The unification scheme of active galactic nuclei (AGNs) invokes an optically thick molecular torus component hiding the broad emission line region. Assuming the presence of a thick neutral component in the molecular torus characterized by a…
Radio continuum and polarization observations of the entire Cygnus Loop at 6cm wavelength were made with the Urumqi 25m telescope. The 6cm map is analysed together with recently published maps from the Effelsberg 100m telescope at 21cm and…
We present optical spectropolarimetric and imaging polarimetric observations of four high-redshift radio galaxies (HzRGs) obtained with the 10-m Keck I telescope. A broad Mg II emission line is detected in the total and polarized flux…