Accreting black holes contribute 40-60% of the mean Hα intensity and 60-80% of the mean He II intensity at cosmic noon in LIM, dominating the shot-noise term and boosting small-scale power.
A., Orlitov´ a, I.: Low-redshift Lyman continuum leaking galaxies with high [O III]/[O II] ratios
7 Pith papers cite this work. Polarity classification is still indexing.
abstract
We present observations with the Cosmic Origins Spectrograph onboard the Hubble Space Telescope of five star-forming galaxies at redshifts z in the range 0.2993-0.4317 and with high emission-line flux ratios O32=[OIII]5007/[OII]3727 ~ 8-27 aiming to detect the Lyman continuum (LyC) emission. We detect LyC emission in all galaxies with the escape fractions fesc(LyC) in a range of 2-72 per cent. A narrow Ly-alpha emission line with two peaks in four galaxies and with three peaks in one object is seen in medium-resolution COS spectra with a velocity separation between the peaks Vsep varying from ~153 km/s to ~345 km/s. We find a general increase of the LyC escape fraction with increasing O32 and decreasing stellar mass M*, but with a large scatter of fesc(LyC). A tight anti-correlation is found between fesc(LyC) and Vsep making Vsep a good parameter for the indirect determination of the LyC escape fraction. We argue that one possible source driving the escape of ionizing radiation is stellar winds and radiation from hot massive stars.
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Empirical three-parameter fit to f_esc(M_h,z) yields steep redshift evolution with population-averaged escape fraction rising from ~2% at z=5 to ~9% at z=12.
Two z~6.6 galaxies host overmassive black holes and show remnant ionized bubbles from recent quasar episodes, with BH-to-stellar mass ratios 400-800 times above the local relation.
Analysis of JWST/NIRSpec Prism spectra for 25 z>=10 galaxies finds burstiness correlates with strong UV lines, short depletion times, and DLA-induced redshift biases of 0.39 and 0.14 with marginal impact on UV luminosity density.
JWST spectra reveal that two z~7 galaxies already show near-solar iron-to-silicon ratios with no strong odd-even effect, favoring early Type Ia supernovae over pair-instability supernovae as the source of iron enrichment.
SPRITE SmallSat is predicted to detect LyC from low-z LCEs using advanced FUV coatings and spectrograph, with eight prior LCEs as commissioning targets to validate sensitivity and enable a larger survey bridging low- and high-redshift studies.
SKA-Mid is predicted to yield samples of 10-100 low-metallicity Lyman continuum emitting galaxies per square degree, enabling multi-wavelength studies of feedback processes linked to ionizing photon escape.
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Life After the Quasar: Overmassive Black Holes and Remnant Ionised Bubbles in and Around Two z~6.6 Galaxies
Two z~6.6 galaxies host overmassive black holes and show remnant ionized bubbles from recent quasar episodes, with BH-to-stellar mass ratios 400-800 times above the local relation.