Related papers: New theoretical Fe II templates for bright quasars
Eigenvector 1 (EV1) was found to be the dominant component behind the significant correlations for the measured parameters in quasar spectra (Boroson & Green, 1992). The parameter R$_{\mathrm{FeII}}$, which strongly correlates to the EV1,…
It has been suggested that hot stellar wind gas in a bow shock around an exoplanet is sufficiently opaque to absorb stellar photons and give rise to an observable transit depth at optical and UV wavelengths. In the first part of this paper,…
Type II quasars are luminous Active Galactic Nuclei whose centers are obscured by large amounts of gas and dust. In this contribution we present 3-band HST images of nine type II quasars with redshifts 0.25<z<0.4 selected from the Sloan…
Quasar-driven outflows on galactic scales are a routinely invoked ingredient for galaxy formation models. We report the discovery of ionized gas nebulae as traced by [O III] $\lambda$5007 AA emission surrounding three luminous red quasars…
We exploit ionization-parameter mapping as a powerful tool to measure the optical depth of star-forming HII regions. Our simulations using the photoionization code CLOUDY and our new, SURFBRIGHT surface brightness simulator demonstrate that…
Using 190,000 spectra from the seventeenth data release of the Sloan Digital Sky Survey, we investigate the ultraviolet emission line properties in z=2 quasars. Specifically, we quantify how the shape of CIV 1549A and the equivalent width…
We investigate the discrepancy between oxygen abundance estimations for narrow-line regions (NLRs) of Active Galactic Nuclei (AGNs) type Seyfert 2 derived by using direct estimations of the electron temperature (Te-method) and those derived…
We present near-infrared spectroscopy of the NLS1 galaxy PHL1092 (z=0.394), the strongest FeII emitter ever reported, combined with optical and UV data. We modeled the continuum and the broad emission lines using a power-law plus a black…
Quasar outflows are fundamental components of quasar environments that might play an important role in feedback to galaxy evolution. We report on the emergence of a remarkable new outflow absorption-line system in the quasar PG1411+442…
We used a large, homogeneous sample of 4178 z <= 0.8 Seyfert 1 galaxies and QSOs selected from the Sloan Digital Sky Survey to investigate the strength of Fe II emission and its correlation with other emission lines and physical parameters…
The physics and demographics of type 2 quasars remain poorly understood, and new samples of such objects selected in a variety of ways can give insight into their physical properties, evolution, and relationship to their host galaxies. We…
Intensive monitoring campaigns have recently attempted to measure the time delays between multiple images of gravitational lenses. Some of the resulting light-curves show puzzling low-level, rapid variability which is unique to individual…
We report the detection of near-infrared (NIR) [Fe II] (1.644 $\mu$m) and H$_{2}$ 1-0 S(1) (2.122 $\mu$m) line features associated with Galactic supernova remnants (SNRs) in the first quadrant using two narrowband imaging surveys, UWIFE and…
The optical [N I] doublet near 5200 {\AA} is anomalously strong in a variety of emission-line objects. We compute a detailed photoionization model and use it to show that pumping by far-ultraviolet (FUV) stellar radiation previously posited…
We develop a count-in-cells approach to the distribution of ultraviolet background fluctuations that includes source clustering. We demonstrate that an exact expression can be obtained if the clustering of ionizing sources follows the…
We present [Fe II] 1.644 um features around ultracompact H II regions (UCHIIs) found on a quest for the "footprint" outflow features of UCHIIs---the feature produced by the outflowing materials ejected during the earlier, active accretion…
A comparison is made between the properties of CAL 83, CAL 87, RX J0513.9-6951, 1E 0035.4-7230 (SMC 13), RX J0019.8+2156, and RX J0925.7-4758, all supersoft X-ray binaries. Spectra with the same resolution and wavelength coverage of these…
We explore mechanisms to produce extremely high Ly-alpha/HeII flux ratios, or to enhance the observed number of Ly-alpha photons per incident ionizing photon, in extended AGN-photoionized nebulae at high-redshift. Using photoionization…
We present YJHK photometry, or a subset, for the six Y dwarfs discovered in WISE data by Cushing et al.. The data were obtained using NIRI on the Gemini North telescope. We also present a far-red spectrum obtained using GMOS-North for…
We present Keck optical spectra of SN 2002cx, the most peculiar known Type Ia supernova (SN Ia), taken 227 and 277 days past maximum light. Astonishingly, the spectra are not dominated by the forbidden emission lines of iron that are a…