Related papers: Hbeta Profiles in Quasars: Evidence for an Interme…
A small fraction of quasars have long been known to show bulk velocity offsets in the broad Balmer lines with respect to the systemic redshift of the host galaxy. Models to explain these offsets usually invoke broad-line region gas…
We performed 3D spectroscopic observations of Mrk 493 in order to investigate the Fe II emitting region and their possible connection with the Hydrogen emitting region. We found that there is a strong Fe II emission in an extensive region ~…
We present spectrophotometric observations of the Broad Line Radio Galaxy OQ 208 (Mrk 668, 1404+286) obtained between 1985 and 1991. We show that the Balmer line fluxes and profile shapes undergo remarkable changes. The ratio of intensities…
The quasar SDSS 0956+5128 exhibits three distinct velocity components with large offsets in emission: the systemic velocity of [O II], [O III] and [Ne III] narrow lines have redshift $z=0.7142$; broad Mg II line is shifted by $-1200$ km…
The identification of a virial broadening estimator in the quasar UV rest frame suitable for black hole mass computation at high redshift has become an important issue. We compare the HI Balmer H-beta line width to the ones of two…
The velocities of the [O III] 5007 and optical Fe II emission lines, measured relative to the systemic redshifts of 2265 QSOs by Hu et al. (2008), show the signature of a disklike BLR structure with polar outflows. Objects with large [O…
Motivated by the recent discovery of an Halpha emission line component originating close to the white dwarf primary in the post-common-envelope binary (PCEB) LTT 560, we have undertaken a spectroscopic snapshot survey on 11 short-period…
We have obtained quasi-simultaneous ultraviolet-optical spectra for 22 out of 23 quasars in the complete PG-X-ray sample with redshift, z<0.4, and M_B<-23. The spectra cover rest-frame wavelengths from at least Lyman-alpha to H-alpha. Here…
An infrared-selected, narrow-line QSO has been found to exhibit an extraordinarily broad Halpha emission line in polarized light. Both the extreme width (35,000 km/sec full-width at zero intensity) and 3,000 km/sec redshift of the line…
Results of the analysis of the variability of the H$\beta$ and H$\alpha$ broad emission-line profiles and the He II $\lambda4686$A emission-line fluxes in the 3C 390.3 nucleus during 1992-2014 are present. The observed velocity-dependent…
We investigate the structure of the Mg II broad line emission region in a sample of 284 Type 1 active galactic nuclei (AGNs), through comparing the kinematical parameters of the broad Mg II and broad H$\beta$ lines. We found that the Mg II…
Moderate-resolution spectra of the H$\beta$--[O III] $\lambda$5007 region have been obtained for 41 radio-loud quasars in order to investigate relationships among their broad- and narrow-line profiles, radio structures, and X-ray…
Quasars can be used as a complementary tool to SN Ia to probe the distribution of dark energy in the Universe by measuring the time delay of the emission line with respect to the continuum. The understanding of the Mg II emission line…
We study the kinematics of the giant H II regions NGC 5455 and NGC 5471 located in the galaxy M101, using integral field observations that include the Hbeta and [O III] 5007 emission lines, obtained with the Keck Cosmic Web Imager. We…
We present a reverberation mapping (RM) experiment that combines broad- and intermediate-band photometry; it is the first such attempt targeting a sample of 13 quasars at $0.2<z<0.9$. The quasars were selected to have strong H$\alpha$ or…
The broad MgII doublet has been much studied in connection with its potentially important role as a virial estimator of black hole mass in high redshift quasars. An important task is therefore identification of any line components likely…
The results of spectroscopic study of Ae Herbig star RR Tau are reported. The observations were carried out with a moderate resolution. In accordance with the presented data the Halpha line exhibits a double-peaked emission profile. The…
We explore the variability of quasars in the MgII and Hbeta broad emission lines and UV/optical continuum emission using the Sloan Digital Sky Survey Reverberation Mapping project (SDSS-RM). This is the largest spectroscopic study of quasar…
We have explored the nature of the extended emission-line region around the z=0.37 quasar 4C 37.43, using extensive ground-based and HST imaging and spectroscopy. The velocity field of the ionized gas shows gradual gradients within…
Recent papers published in the last years contributed to resolve the enigma on the hypothetical Be nature of the hot pulsating star $\beta$ Cep. This star shows variable emission in the H$\alpha$ line, typical for Be stars, but its…