655 citations · 10k across the 141 of their papers we have counts for
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The primordial Helium-4 abundance determination: systematic effects
T. X. Thuan, Y. I. Izotov
By extrapolating to O/H = N/H = 0 the empirical correlations Y-O/H and Y-N/H defined by a relatively large sample of ~ 45 Blue Compact Dwarfs (BCDs), we have obtained a primordial…
The KPNO International Spectroscopic Survey. III. [O III]-selected Survey List
John J. Salzer, Caryl Gronwall, Vicki L. Sarajedini +8
The KPNO International Spectroscopic Survey (KISS) is an objective-prism survey for extragalactic emission-line objects. It combines many of the features of previous slitless spect…
Optical & NIR Surface Photometry of I Zw 18
P. Papaderos, Yu. I. Izotov, K. G. Noeske +2
Using HST and ground-based optical and NIR data, we investigate whether the blue compact dwarf (BCD) galaxy I Zw 18 has an extended low-surface-brightness (LSB) older stellar popul…
The N/O abundance ratio in the lowest-metallicity blue compact dwarf galaxies
Y. Izotov, F. Chaffee, C. Foltz +6
The results of the N/O abundance determination in a sample of low-metallicity blue compact dwarf (BCD) galaxies based on new spectroscopic observations with large telescopes (Keck,…
The gaseous content of the Blue Compact Galaxy Mrk 59
A. Lecavelier des Etangs, T. X. Thuan, Y. I. Izotov
FUSE far-UV spectroscopy of the nearby metal-deficient (Zo/8) cometary Blue Compact Dwarf galaxy Mrk59 have been used to investigate element abundances in its interstellar medium.…
A spectroscopic study of component C and the extended emission around I Zw 18
Y. I. Izotov, F. H. Chaffee, C. B. Foltz +5
Long-slit Keck II, 4m Kitt Peak, and 4.5m MMT spectrophotometric data are used to investigate the stellar population and the evolutionary status of I Zw 18C, the faint C component…
The evolutionary status of the low-metallicity blue compact dwarf galaxy SBS 0940+544
N. G. Guseva, Y. I. Izotov, P. Papaderos +6
We present the results of spectrophotometry and V,R,I, Halpha CCD photometry of the blue compact dwarf (BCD) galaxy SBS 0940+544. Broad-band images taken with the 2.1m KPNO and 1.2…
The He abundance in the metal-deficient blue compact dwarf galaxies Tol 1214-277 and Tol 65
Y. I. Izotov, F. H. Chaffee, R. F. Green
We present high-quality Keck telescope spectroscopic observations of the two metal-deficient blue compact dwarf (BCD) galaxies Tol 1214-277 and Tol 65. These data are used to deriv…
Deep spectroscopy of the low-metallicity blue compact dwarf galaxy SBS 0335-052
Y. I. Izotov, F. H. Chaffee, D. Schaerer
The results of deep long-slit spectroscopy of the extremely low-metallicity blue compact dwarf (BCD) galaxy SBS 0335-052 are presented. Down to intensity levels of 10^{-3 ... -4} o…
Collisional excitation of hydrogen and the determination of the primordial helium abundance from H II regions
G. Stasinska, Y. I. Izotov
This paper investigates the effect of collisional enhancement of the hydrogen lines on the derivation of the helium abundances in low metallicity H II regions. For this, we have co…
The Hamburg/SAO Survey for Emission--Line Galaxies. V. The Fifth List of 161 Galaxies
A. V. Ugryumov, D. Engels, A. Y. Kniazev +12
We present the fifth list with results of the Hamburg/SAO Survey for Emission-Line Galaxies (HSS therein, SAO -- Special Astrophysical Observatory, Russia). The list is a result of…