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1. The Lyman Continuum Escape Survey: Connecting Time-dependent [O iii] and [O ii] Line Emission with Lyman Continuum Escape Fraction in Simulations of Galaxy Formation

   https://doi.org/10.3847/2041-8213/abbd8e  

   Barrow, Kirk S. ; Robertson, Brant E. ; Ellis, Richard S. ; Nakajima, Kimihiko ; Saxena, Aayush ; Stark, Daniel P. ; Tang, Mengtao ( October 2020 , The Astrophysical Journal)
2. Near Field Cosmology: Translating Galaxy Properties to Lyman-alpha and Lyman-continuum escape fractions

   Olivieri Villalvazo, Mario A. ; Pilon, Andrew ; Venkatesan, Aparna ; Rosenberg, Jessica ; Gronke, Max ; Salzer, John ; Cannon, John M. ; Janowiecki, Steven ( January 2019 , American Astronomical Society, AAS Meeting)

   We present our analyses of 39 selected star-forming low- to intermediate-mass low-redshift galaxies from the KISSR survey. These galaxies were selected as being representative in the local volume of the kinds of early galaxies that might have hosted the first stars, and span a range of galaxy properties (EWHA, reddening, metallicity, stellar mass). The KISSR systems contain a population, in appearance resembling "purple peas", with potentially steep UV slopes and high equivalent widths in H-alpha. Using archival GALEX data and theoretical models of radiation transport in dusty galaxies with clumpy gas media, we translate measurements of the UV slopes of these low-mass low-z KISSR galaxies to their escape fractions in Ly-alpha (LyA) and Ly-continuum (LyC) radiation, confirming a relationship between a galaxy's steep UV spectral slope and a significant (> 0.1) LyA escape fraction. This relationship is seen in existing data of low- to intermediate-mass galaxies in the local volume (please see accompanying poster by Pilon et al. at this meeting). We also translate measured LyA escape fractions in the literature for 14 LARS galaxies and a few dozen green pea galaxies to their LyC escape fractions using similar modeling. This work was supported by the University of San Francisco (USF) Faculty Development Fund, the USF Student Travel Fund, and by the Undergraduate ALFALFA Team through NSF grant AST-1637339. 

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3. Resolved Lyman-α properties of a luminous Lyman-break galaxy in a large ionized bubble at z = 6.53

   https://doi.org/10.1093/mnras/stz3554  

   Matthee, Jorryt ; Sobral, David ; Gronke, Max ; Pezzulli, Gabriele ; Cantalupo, Sebastiano ; Röttgering, Huub ; Darvish, Behnam ; Santos, Sérgio ( December 2019 , Monthly Notices of the Royal Astronomical Society)

   The observed properties of the Lyman-α (Ly α) emission line are a powerful probe of neutral gas in and around galaxies. We present spatially resolved Ly α spectroscopy with VLT/MUSE targeting VR7, a UV-luminous galaxy at z = 6.532 with moderate Ly α equivalent width (EW0 ≈ 38 Å). These data are combined with deep resolved [CII]158μm spectroscopy obtained with ALMA and UV imaging from HST and we also detect UV continuum with MUSE. Ly α emission is clearly detected with S/N ≈ 40 and FWHM of 374 km s−1. Ly α and [C ii] are similarly extended beyond the UV, with effective radius reff = 2.1 ± 0.2 kpc for a single exponential model or r$_{\rm eff, Ly\alpha , halo} = 3.45^{+1.08}_{-0.87}$ kpc when measured jointly with the UV continuum. The Ly α profile is broader and redshifted with respect to the [C ii] line (by 213 km s−1), but there are spatial variations that are qualitatively similar in both lines and coincide with resolved UV components. This suggests that the emission originates from two components with plausibly different H i column densities. We place VR7 in the context of other galaxies at similar and lower redshift. The Ly α halo scale length is similar at different redshifts and velocity shifts with respect to the systemic are typically smaller. Overall, we find little indications of a more neutral vicinity at higher redshift. This means that the local (∼10 kpc) neutral gas conditions that determine the observed Ly α properties in VR7 resemble the conditions in post-reionization galaxies.

    

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4. Lyman alpha and Lyman continuum emission of Mg  ii -selected star-forming galaxies

   https://doi.org/10.1093/mnras/stac1899  

   Izotov, Y. I. ; Chisholm, J. ; Worseck, G. ; Guseva, N. G. ; Schaerer, D. ; Prochaska, J. X. ( July 2022 , Monthly Notices of the Royal Astronomical Society)

   We present observations with the Cosmic Origins Spectrograph onboard the Hubble Space Telescope of seven compact low-mass star-forming galaxies at redshifts, z, in the range 0.3161–0.4276, with various O3Mg2 = [O iii] λ5007/Mg ii λ2796+2803 and Mg2 = Mg ii λ2796/Mg ii λ2803 emission-line ratios. We aim to study the dependence of leaking Lyman continuum (LyC) emission on the characteristics of Mg ii emission together with the dependencies on other indirect indicators of escaping ionizing radiation. LyC emission with escape fractions fesc(LyC) = 3.1–4.6 per cent is detected in four galaxies, whereas only 1σ upper limits of fesc(LyC) in the remaining three galaxies were derived. A strong narrow Lyα emission line with two peaks separated by $V_{\rm sep}\, \sim$ 298–592 km s−1 was observed in four galaxies with detected LyC emission and very weak Lyα emission is observed in galaxies with LyC non-detections. Our new data confirm the tight anticorrelation between fesc(LyC) and Vsep found for previous low-redshift galaxy samples. Vsep remains the best indirect indicator of LyC leakage among all considered indicators. It is found that escaping LyC emission is detected predominantly in galaxies with Mg$_2\, \gtrsim$ 1.3. A tendency of an increase of fesc(LyC) with increasing of both the O3Mg2 and Mg2 is possibly present. However, there is substantial scatter in these relations not allowing their use for reliable prediction of fesc(LyC).

    

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5. Reconstructing the gravitational lensing potential from the Lyman-$\alpha$ forest

   https://doi.org/10.1051/0004-6361/202038056  

   Metcalf, R.B. ; Tessore, N. ; Croft, R.A.C. ( October 2020 , Astronomy & Astrophysics)