Related papers: Broad-line Balmer Decrements in Blue Active Galact…
In this paper we study the properties of the optical spectra of Type 1 active galactic nuclei (AGNs) by using the unobscured hard X-ray emission as a diagnostic. We develop the `Correlation Spectrum Technique' (CST) and use this to show the…
We use multiwavelength data from the Galaxy And Mass Assembly (GAMA) and Herschel ATLAS (H-ATLAS) surveys to compare the relationship between various dust obscuration measures in galaxies. We explore the connections between the ultraviolet…
We present an updated and revised analysis of the relationship between the Hbeta broad-line region (BLR) radius and the luminosity of the active galactic nucleus (AGN). Specifically, we have carried out two-dimensional surface brightness…
Low-redshift active galactic nuclei (AGNs) with extremely blue optical spectral indices are shown to have a mean, velocity-averaged, broad-line H$\alpha$/H$\beta$ ratio of $\thickapprox 2.72 \pm 0.04$, consistent with a Baker-Menzel Case B…
We present a new model to explain the appearance of red/blue-shifted broad low-ionization emission lines, especially emission lines in optical band, which is commonly considered as an indicator of radial motion of the line emitting gas in…
We report on continued, $\sim$15 year-long, broad Balmer emission lines in three metal-poor dwarf emission-line galaxies selected from Sloan Digital Sky Survey spectroscopy. The persistent luminosity of the broad Balmer emission indicates…
More than 50% of Active Galactic Nuclei (AGNs) are suspected to be red and affected by dust-obscuration. Meanwhile, popular spectral diagnostics of AGNs are based on optical or ultraviolet light, making the dust obscuration as a primary…
We present observational evidences that dust in the circumnuclear region of AGNs has different properties than in the Galactic diffuse interstellar medium. By comparing the reddening of optical and infrared broad lines and the X-ray…
We reinvestigate the relationship between the characteristic broad-line region size (R_blr) and the Balmer emission-line, X-ray, UV, and optical continuum luminosities. Our study makes use of the best available determinations of R_blr for a…
We have conducted a systematic search of low-mass black holes (BHs) in active galactic nuclei (AGNs) with broad Halpha emission lines, aiming at building a homogeneous sample that is more complete than previous ones for fainter, less highly…
We analyze the ratios of the broad hydrogen Balmer emission lines (from H\alpha to H\epsilon) in the context of estimating the physical conditions in the broad line region (BLR) of active galactic nuclei (AGN). The Balmer emission lines are…
Deep H$\alpha$ images of a faint emission complex 4.0 x 5.5 degrees in angular extent and located far off the Galactic plane at l = 70.0 degrees, b=-21.5 degrees reveal numerous thin filaments suggestive of a supernova remnant's shock…
A new, complete sample of 14,584 broad-line AGNs at $z<0.35$ is presented, which are uncovered homogeneously from the complete database of galaxies and quasars observed spectroscopically in the Sloan Digital Sky Survey Seventh Data Release.…
We present the star formation and dust attenuation properties for a sample of 602 galaxies at redshifts $\rm{3<z<7}$, as part of the JADES survey. Our analysis is based on measurements of the $\rm{H}\alpha/\rm{H}\beta$ Balmer Decrement…
We present the results of an optical spectroscopic survey designed to search for low-luminosity, "dwarf" Seyfert nuclei in a magnitude-limited sample of 486 bright, northern galaxies. Moderate-resolution spectra of exceptionally high…
We compare the infrared excess (IRX) and Balmer decrement (${\rm H\alpha/H\beta }$) as dust attenuation indicators in relation to other galaxy parameters using a sample of $\sim$32 000 local star-forming galaxies (SFGs) carefully selected…
We present a high-quality, homogeneous sample of 157 H$\beta$ reverberation-mapped active galactic nuclei (RM AGNs) spanning redshifts $0.00308 \leq z \leq 0.8429$, which is approximately 3.8 times larger than the previously available…
We use medium resolution JWST/NIRSpec observations from the Cosmic Evolution Early Release Science (CEERS) Survey to place the first constraints on dust attenuation and star formation based on the Paschen lines for a sizable sample of 63…
Using star-forming galaxies sample in the nearby Universe (0.02<z<0.10) selected from the SDSS (DR7) and GALEX all-sky survey (GR5), we present a new empirical calibration for predicting dust extinction of galaxies from H-alpha-to-FUV flux…
We investigate the relationships between infrared excess (IRX=$L_{\rm IR}/L_{\rm UV}$) and Balmer decrement (${\rm H}\alpha/{\rm H}\beta$) as indicators of dust attenuation for 609 ${\rm {H\,{\small II}}}$ regions at scales of $\sim 50-200$…