Related papers: Line Emission from Stellar Winds in Active Galacti…
Here we present observational evidence that the broad emission line region (BELR) of active galactic nuclei (AGN) generally has an outer boundary. This was already clear for sources with an obvious transition between the broad and narrow…
The Lyman-alpha emission line is the strongest feature in the spectrum of most high redshift galaxies, and is typically observed as being highly asymmetric due to galactic outflows. Quantifying this asymmetry is challenging. Here, we…
We present a new model for computing consistently the line and continuum emission from galaxies, based on a combination of recent population synthesis and photoionization codes. We use effective parameters to describe the HII regions and…
Active Galactic Nuclei (AGN) are axisymmetric systems to first order; their observed properties are likely strong functions of inclination with respect to our line of sight, yet the specific inclinations of all but a few AGN are generally…
Spectra of the He I 10830 Angstrom line were obtained with NIRSPEC on the Keck 2 telescope for metal-deficient field giant stars. This line is ubiquitous in stars with T_eff greater than 4500K and M_V fainter than -1.5. Fast outflows are…
The observed iron K-alpha fluorescence lines in Seyfert galaxies provide strong evidence for an accretion disk near a supermassive black hole as a source of the line emission. Previous studies of line emission have considered only…
An intrinsically narrow line emitted by an accretion disk around a black hole appears broadened and skewed as a result of the Doppler effect and gravitational redshift. The fluorescent iron line in the X-ray band at 6.4-6.9keV is the…
Binary black hole mergers encode information about their environment and the astrophysical processes that led to their formation. Measuring the redshift dependence of their merger rate will help probe the formation and evolution of galaxies…
We report here our comparative analysis of active galactic nucleus (AGN) and star formation (SF) characteristics of a sample of narrow-line Seyfert 1 (NLS1) and broad-line Seyfert 1 (BLS1) galaxies. Our sample consisted of 373 BLS1 and 240…
We have conducted a comprehensive mid-IR spectroscopic investigation of 67 Low Ionization Nuclear Emission Line Regions (LINERs) using archival observations from the high resolution modules of the Infrared Spectrograph on board the Spitzer…
With the aim of building a data-set of spectral properties of well studied early-type galaxies showing emission lines, we present intermediate resolution spectra of 50 galaxies in the nearby Universe. The sample, which covers several of the…
Narrow Line Seyfert 1 galaxies (NLS1s) are intriguing due to their continuum as well as emission line properties. The observed peculiar properties of the NLS1s are believed to be due to accretion rate close to Eddington limit. As a…
The `Bloated Stars Scenario' proposes that AGN broad line emission originates in the winds or envelopes of bloated stars (BS). Alexander and Netzer (1994, 1996) established that ~ 5e4 BSs with dense, decelerating winds can reproduce the…
Cosmological hydrodynamical simulations of galaxy formation in representative regions of the Universe typically need to resort to subresolution models to follow some of the feedback processes crucial for galaxy formation. Here, we show that…
Outflows play a major role in the evolution of galaxies. However, we do not have yet a complete picture of their properties (extension, geometry, orientation and clumpiness). For low-luminosity Active Galactic Nuclei (AGNs), in particular,…
We present the results of a Lya profile analysis of 12 Lya emitters (LAEs) at z = 2.2 with high-resolution Lya spectra. We find that all 12 objects have a Lya profile with the main peak redward of the systemic redshift defined by nebular…
Over the last years a new generation of model atmosphere codes, which include the effects of metal line-blanketing of millions of spectral lines in NLTE, has been used to re-determine the properties of massive stars through quantitative…
Strong both broad and narrow emission lines from central broad emission line regions (BLRs) and narrow emission line regions (NLRs) are fundamental spectroscopic characteristics of broad line Active Galactic Nuclei (BLAGNs). Lack of central…
A two-components model for Broad Line Region (BLR) of Active Galactic Nuclei (AGN) has been suggested for many years but not widely accepted (e.g., Hu et al. 2008; Sulentic et al. 2000; Brotherton et al. 1996; Mason et al. 1996). This model…
Early-time observations of the Type II supernovae (SNe) 2013cu and 2013fs have revealed an interaction of ejecta with material near the star surface. Unlike the Type IIn SN2010jl, which interacts with a dense wind for ~1yr, the interaction…