Cosmic Dawn at High Latitudes Conference

Session

Session 5

26 Jun 2024, 09:15

Beijer auditorium (Swedish Royal Academy of Sciences)

149. How useful are simulations for understanding reionization and its sources?

Joakim Rosdahl

26/06/2024, 09:15

41. Galaxies as agents of cosmic reionization: new results from JWST WFSS and VLT/MUSE observations

Jorryt Matthee (Institute of Science and Technology Austria)

26/06/2024, 09:45

Reionization marks the last major phase transition of matter in the Universe and its completion had crucial impact on the formation of the smallest galaxies. While reionization roughly encapsulated the first Gyr of cosmic time, the precise timing, topology and the sources of ionizing photons are unknown. In my talk, I will mainly present results on the spectroscopic properties of galaxies in...

109. Radiation-Driven Superwinds and Lyman Continuum Escape in Local Reionization-Era Analogs

Lena Komarova (University of Michigan)

26/06/2024, 10:00

A key unknown in our understanding of cosmic reionization is the feedback mechanisms that enabled Lyman continuum (LyC) to escape in the earliest starbursts. One clue comes from Green Pea (GP) galaxies, the largest class of local (z ~ 0.3) LyC emitters. Most GPs show broad nebular emission-line wings of unknown origin, reaching 200-1000 km/s. The broad-wing velocity has been shown to correlate...

138. Are local diagnostics for LyC escape fraction valid during the EoR?

Claudia Scarlata

26/06/2024, 10:15

The escape fraction of Lyman Continuum radiation (f_esc) remains the most uncertain parameter in modeling the epoch of reionization. Depending on its value, and its dependency on galaxy luminosities, different ionization histories and topologies are expected. Photons more energetic than 13.6eV escaping from a galaxy are readily absorbed in the intergalactic medium (IGM) making the f_esc...

33. LyC Escape and IGM Tomography Using the 600-900Å Continuum of the Sunburst Arc

Michelle Berg (University of Texas at Austin)

26/06/2024, 10:30

The Sunburst Arc (z~2.37) is a confirmed Lyman continuum leaker galaxy and has been uniquely lensed where its single leaking region is imaged 12 times over four separate arcs. Using HST/WFC3 UVIS G280 grism observations, we extracted the spectra of the leaking region to determine the shape of the stellar continuum from 600-900Å (produced by young, massive O and B stars) for the first time. The...

57. The impact of mergers on the Lyman Continuum photons escape in Galaxies during the epoch of reionization

Sara Mascia (INAF OAR, Università degli Studi di Roma "Tor Vergata")

26/06/2024, 11:15

The opacity of the intergalactic medium does not allow a direct measurement of Lyman continuum (LyC) emission at redshifts exceeding 4.5. Consequently, we are increasingly relying on indirect indicators of LyC emission that are well tested at low and intermediate redshift. In this study, we use several such indirect indicators, based on parameters like UV-beta slope, E(B-V), UV magnitude, and...

94. Influence of galactic mergers on the escape of LyC radiation during reionization

Ivan Kostyuk (Max Planck Institute for Astrophysics)

26/06/2024, 11:30

Low mass galaxies are one of the main sources of Lyman continuum (LyC) photons, which ionized the intergalactic medium during cosmic reionization. However, the escape fraction of LyC photons from these galaxies depends on the properties and dynamics of the neutral gas that surrounds the star-forming regions. Galactic mergers can affect both the star formation rate and the gas distribution...

19. Fluctuations and Evolution of the Ionizing Background and Mean Free Path during the Late Stages of Reionization

Huanqing Chen (Canadian Institute for Theoretical Astrophysics)

26/06/2024, 11:45

Measurements of the ionizing background and the mean free path (MFP) at the end of reionization offer valuable insights into the first generation of sources that ionized the universe. With increasing observational data from this epoch, a better theoretical understanding is imperative to interpret the data accurately.
The CROC simulations are uniquely poised to interpret observational data,...

75. The forest at EndEoR: The effect of Lyman Limit Systems on the End of Reionisation

Ivelin Georgiev (Stockholm University)

26/06/2024, 12:00

The Epoch of Reionisation (EoR) was the period of the Universe during which the neutral hydrogen present in the intergalactic medium (IGM) was ionised by Ultraviolet radiation from sources inside early galaxies. Significant progress has been made in modelling cosmic reionisation through numeric and semi-numeric codes. However, the end of reionisation has been studied less. In radiative...

141. Impact of Self-shielding Minihalos on the Lya Forest at High Redshift

Hyunbae Park

26/06/2024, 12:15

Dense gas in minihalos can shield themselves from reionization for ~100 Myr after being exposed to UV background. These self-shielded systems, often unresolved in cosmological simulations, can introduce strong absorption in quasar spectra. We present the first systematic study on the impact of these systems on the Lya forest. We find that the incidence rate of damped Lya absorbers increases by...

96. Linking ionized gas kinematics and the escape of ionizing photons in low-redshift analogs of reionization galaxies

Ricardo Amorin (CEFCA, Spain)

Compact low-metallicity starbursts, such as the green pea (GP) galaxies at z~0.1-0.3, are excellent low-redshift analogs of reionization galaxies. The direct detection of Lyman continuum (LyC) emission from GPs observed with HST-COS in the far-UV has opened a new avenue to study the main physical processes governing the escape of ionizing photons from star-forming galaxies and probe indirect...