Related papers: The Intermediate Line Region and the Baldwin Effec…
In this presentation, we report the results of intraday variability in the optical (BVRI bands) and hard X-ray band (3-79 keV) in a number of blazars. In the optical microvariability studies of the blazars S5 0716+714 and BL Lac, we…
We have explored the role environmental factors play in determining characteristics of young stellar objects in nearby dwarf irregular and Blue Compact Dwarf galaxies. Star clusters are characterized by concentrations, masses, and formation…
The flat-spectrum radio quasar B2 1633+382 (4C 38.41) has been monitored for several years and has presented correlated variability in multiple wavelengths. In this article, we are performing different analyses for multiple frequencies,…
The intrinsic Baldwin effect is an anti-correlation between the line equivalent width and the flux of the underlying continuum detected in a single variable active galactic nucleus (AGN). This effect, in spite of the extensive research, is…
Emission lines in X-ray spectra of clusters of galaxies reveal the presence of heavy elements in the diffuse hot plasma (the Intra Cluster Medium, or ICM) in virial equilibrium in the dark matter potential well. The relatively simple…
The Infrared Space Observatory (ISO) has provided the first complete mid-IR spectra for a wide range of objects. Almost all of these spectra are dominated by the well-known infrared emission features at 3.3, 6.2, 7.7, and 11.2 $\mu$m, the…
Line profile distortions are commonly observed in gravitationally lensed quasar spectra. These distortions are caused by microlensing from the stars in the lensing galaxy, which produce differential magnification of spatially and…
The extremely faint, temperature sensitive ``auroral'' emission line [N II] 5755 has been detected from the low density ionized gas along the sight line toward l = 130.0, b = -7.5 using the Wisconsin H-Alpha Mapper (WHAM). The intensity of…
The flux and line shape of the fine-structure transitions of \NeII\ and \NeIII\ at 12.8 and 15.55\,$\mu$m and of the forbidden transitions of \OI\ $\lambda6300$ are calculated for young stellar objects with a range of mass-loss rates and…
The variations of the metallicity and ionization parameter in HII regions are usually thought to be the dominant factors that produce the variations we see in the observed emission line spectra. There is an increasing amount of evidence…
In radio bands, the study of compact radio sources can be affected by propagation effects through the Interstellar Medium. These are usually attributed to the presence of turbulent intervening plasma along the line of sight. Here, two of…
We previously built a sample of 14,012 extremely variable quasars (EVQs) based on SDSS and Pan-STARRS1 photometric observations. In this work we present the spectral fitting to their SDSS spectra, and study the spectral variation in 1,259…
The excitation of soliton states in optical layers exhibiting Kerr nonlinearities is theoretically investigated. The optical transmission coefficient is obtained as a function of the nonlinearity power of an incident monochromatic…
The variability of Young Stellar Objects (YSOs) is a crucial tool for understanding the mechanisms driving flux changes. In this study, we present an infrared variability analysis of a large sample of over 20,000 candidate YSOs, using data…
The existence of an anti-correlation between the equivalent width (EW) of the narrow core of the iron Kalpha line and the luminosity of the continuum (i.e. the X-ray Baldwin effect) in type-I active galactic nuclei has been confirmed over…
By observing the near-infrared spectrum of the quasar PG 1116+215 at z = 0.176 and combining with the HST/FOS spectrum, we obtained the relative strengths of three permitted OI lines ({lambda}1304, {lambda}8446, and {lambda}11287) in a…
Mid-infrared (MIR) quasar spectra exhibit a suite of emission features including high ionization coronal lines from the narrow line region (NLR) illuminated by the ionizing continuum, and hot dust features from grains, as well as polycyclic…
Using 192 composite spectra stacked from subsamples of individual SDSS DR7 quasar spectra binned in spectral index, $\alpha_{\lambda}$, and logarithm of monochromatic luminosity at 1450 \AA, $\log{l_{1450}}$, we found that there is a…
We report the first detection of a pair of correlated emission lines in the X-ray spectrum of black hole candidate 4U 1630-47 during its 1996 outburst, based on RXTE observations of the source. At the peak plateau of the outburst, the…
Extreme Scattering Events are radio-wave lensing events caused by AU-sized concentrations of ionised gas. Although they were discovered more than a decade ago we still have no clear picture of the physical nature of the lenses. To…