Related papers: Slit Observations and Empirical Calculations for H…
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…
(Abridged) We examine standard methods of measuring nebular chemical abundances, including estimates based on direct T_e measurements, and also bright-line diagnostics. We use observations of 4 LMC HII regions whose ionizing stars have…
We investigate the [OII] emission-line as a star formation rate (SFR) indicator using integrated spectra of 97 galaxies from the Nearby Field Galaxies Survey (NFGS). The sample includes all Hubble types and contains SFRs ranging from 0.01…
We present a grid of photoionization models for the emission from photoevaporative interfaces between the ionized gas and molecular cloud in blister HII regions. For the density profiles of the emitting gas in the models, we use a general…
We have obtained IFU spectra of 75 SN Ia host galaxies from the Foundation Supernova survey to search for correlations between the properties of individual galaxies and SN Hubble residuals. After standard corrections for light-curve width…
Understanding the complex ionization structure and chemical composition of \hii\ regions poses a significant challenge in astrophysics. The abundance discrepancy problem, characterized by inconsistencies between abundances derived from…
We present a method to derive the logarithmic extinction coefficient in optical wavelengths using the emission lines of HeI. Using this procedure we can avoid selection biases when studying regions with different surface brightness and we…
The possibility that star-forming galaxies may leak ionizing photons is at the heart of many present-day studies that investigate the reionization of the Universe. We test this hypothesis on local blue compact dwarf galaxies of very high…
We have analyzed a uniform sample of 16 evolved HII regions located in a 2 deg X 2 deg Galactic field centered at (l,b) = (30 deg, 0 deg) and observed as part of the Herschel Hi-GAL survey. The evolutionary stage of these HII regions was…
We present results from integral field optical spectroscopy with the Potsdam Multi-Aperture Spectrograph of the Herbig-Haro (HH) object HH 204, with a spatial sampling of 1 x 1 arcsec^2. We have obtained maps of different emission lines,…
Measurements of Type Ia Supernovae (SNe Ia) in the near-infrared (NIR) have been used both as an alternate path to cosmology compared to optical measurements and as a method of constraining key systematics for the larger optical studies.…
We investigate the change in ionizing photons in galaxies between 0.2<z<0.6 using the F2 field of the SHELS complete galaxy redshift survey. We show, for the first time, that while the [OIII]/Hb and [OIII]/[OII] ratios rise, the…
This work aims to the study of the Sh 2-307 HII region and related stellar population. Near-infrared imaging and spectroscopic observations in the direction of Sh 2-307 were performed using OSIRIS at SOAR Telescope. From J-, H- and K-band…
The shape of the OB-star spectral energy distribution is a critical component in many diagnostics of the ISM and galaxy properties. We use single-star HII regions from the LMC to quantitatively examine the ionizing SEDs from widely…
We compare emission line intensities from photoionization models of smooth and fractal shell geometries for low density H II regions, with particular focus on the low-ionization diagnostic diagram [N II]/H-alpha vs H-alpha. Building on…
We present deep spectroscopic (3600 - 24700 A) X-shooter observations of the bright Herbig-Haro object HH1, one of the best laboratories to study the chemical and physical modifications caused by protostellar shocks on the natal cloud. We…
We present multiwavelength investigation of morphology, physical-environment, stellar contents and star formation activity in the vicinity of star-forming region Sh 2-100. It is found that the Sh 2-100 region contains seven HII regions of…
The aim of this paper is to understand the formation of the OI line at 7772 \AA\ in the solar chromosphere. We used SST/CRISP observations to observe OI 7772 \AA\ in several places around the solar limb. We compared the observations with…
The luminosities, colors and H\alpha\ emission for 429 HII regions in 54 LSB galaxies are presented. While the number of HII regions per galaxy is lower in LSB galaxies compared to star-forming irregulars and spirals, there is no indication…
Modelling galaxy formation in hydrodynamic simulations has increasingly adopted various radiative transfer methods to account for photoionization feedback from young massive stars. However, the evolution of HII regions around stars begins…