Feedback is widely recognized as an essential condition for Lyman continuum (LyC) escape in star-forming galaxies. However, the mechanisms by which galactic outflows clear neutral gas and dust remain unclear. In this paper, we model the Mg ii 2796 Å, 2804 Å absorption and emission lines in 29 galaxies taken from the Low- z LyC Survey to investigate the impact of (radiation and mechanical) feedback on LyC escape. Using constraints on Mg + and photoionization models, we map the outflows’ neutral hydrogen content and predict f esc LyC with a multiphase wind model. We measure mass-, momentum, and energy loading factors for the neutral winds, which carry up to 10% of the momentum and 1% of the energy in star formation rate (SFR)-based deposition rates. We use spectral energy distribution template fitting to determine the relative ages of stellar populations, allowing us to identify radiation feedback dominant systems. We then examine feedback related properties (stellar age, loading factors, etc.) under conditions that optimize feedback efficiency, specifically high-SFR surface density and compactness. Our findings indicate that the strongest leakers are radiation feedback dominant, lack deep Mg ii absorption features, but have extended broad components in higher-ionization lines like [O iii ] 5007 Å, as observed by Amorín et al. In contrast, galaxies experiencing supernovae feedback typically exhibit weaker f esc LyC and show evidence of outflows in both Mg ii and higher-ionization lines. We attribute these findings to enhanced LyC escape facilitated by turbulence and cloud fragmentation in intense radiation fields, prolonged in low-metallicity environments experiencing delayed supernova feedback.

Cosmic reionization marks a critical epoch when the first galaxies ionized the intergalactic medium through the escape of Lyman continuum (LyC) radiation. Young, massive star clusters are believed to be the primary LyC sources, yet the physical mechanisms enabling LyC escape remain poorly understood. Most existing studies rely on spatially integrated observations, which lack the resolution to resolve internal galaxy structure and pinpoint where and how LyC photons escape. To address this, we propose a science case for the Habitable Worlds Observatory (HWO) that enables spatially resolved spectroscopy of LyC-emitting star clusters and their environments in low-redshift galaxies. This requires a UV integral field unit (IFU) with coverage down to ~ 900 Angstrom and a spatial resolution of 10-100 pc-capabilities essential for directly detecting LyC escape and mapping the surrounding interstellar medium. With such instrumentation, we will map cluster-scale LyC escape fractions, characterize the physical conditions of the surrounding interstellar medium, and directly observe feedback-driven outflows that facilitate LyC leakage. These observations will enable novel calibrations of indirect LyC indicators at unprecedented spatial resolution and establish direct connections between local LyC processes and those in high-redshift, clumpy star-forming galaxies. In the long run, this program will build the physical framework needed to understand how galaxies reionized the early universe and shaped its subsequent evolution.

One of the fundamental questions of cosmology is the origin and mechanism(s) responsible for the reionization of the Universe beyond z ∼ 6. Many studies have focused on Hubble Space Telescope (HST) Cosmic Origins Spectrograph (COS) observations of local ( z ∼ 0.3) galaxies emitting ionizing radiation (Lyman continuum, or LyC) for insight. However, LyC measurements can depend on chance alignment of optically thin channels with the observer. In addition, low signal in the spectra of these faint LyC emitters inhibits constraints on gas geometry and stellar populations. To circumvent these limitations, we analyze stacks of a consolidated sample of HST/COS observations of the LyC in 89 galaxies at z ∼ 0.3. From fitting of the continuum, we obtain information about the underlying stellar populations, emergent LyC, and neutral interstellar medium geometry. We find that most LyC nondetections are not leaking appreciable LyC ( f esc LyC < 1%), but also that exceptional cases point to spatial variations in the LyC escape fraction f esc LyC . Stellar populations younger than 3 Myr lead to an increase in ionizing feedback, which in turn increases the isotropy of LyC escape. Wolf–Rayet stars and 3–6 Myr populations appear to play little role in LyC escape. Mechanical feedback from supernovae in 8–10 Myr stellar populations is important for anisotropic gas distributions needed for LyC escape. While mechanical feedback is necessary for any LyC escape, high f esc LyC (>5%) also requires a confluence of young stars and ionizing feedback. A two-stage burst of star formation is critical to producing this optimal LyC escape scenario, and should be considered fundamental to identifying LyC emitters at the Epoch of Reionization.

Observations suggest that UV-bright, compact star-forming galaxies produce enough ionizing (Lyman continuum; LyC) photons to reionize the Universe. Yet, the efficiency of LyC escape and the roles of radiation, stellar winds, and supernovae remain uncertain. Using medium-resolution spectra of six nearly identical local star-forming galaxies, we directly trace, for the first time, the evolution of a multiphase wind through individual spectral lines alongside measurements of the LyC escape fraction. We find that LyC escape peaks early, during a period dominated by intense radiation and stellar winds but lacking a fast galactic wind. As the starbursts age, supernovae drive and accelerate the wind, progressively suppressing LyC escape. These results highlight the need for cosmological simulations to incorporate early feedback as a key driver of reionization.

Ultraviolet absorption line spectroscopy is a sensitive diagnostic for the properties of interstellar and circumgalactic gas. Down-the-barrel observations, where the absorption is measured against the galaxy itself, are commonly used to study feedback from galactic outflows and to make predictions about the leakage of H i ionizing photons into the intergalactic medium. Nonetheless, the interpretation of these observations is challenging, and observational compromises are often made in terms of signal-to-noise ratio, spectral resolution, or the use of stacking analyses. In this paper, we present a novel quantitative assessment of UV absorption line measurement techniques by using mock observations of a hydrodynamical simulation. We use a simulated galaxy to create 22,500 spectra in the commonly used Si ii lines while also modeling the signal-to-noise ratio and spectral resolution of recent rest-frame UV galaxy surveys at both high and low redshifts. We show that the residual flux of absorption features is easily overestimated for single line measurements and for stacked spectra. Additionally, we explore the robustness of the partial covering model for estimating column densities from spectra and find underpredictions on an average of 1.25 dex. We show that the underprediction is likely caused by high-column-density sight lines that are optically thick to dust making them invisible in UV spectra.

The origin of Lyman continuum (LyC) photons responsible for reionizing the Universe remains largely unknown, with the fraction of escaping LyC photons from galaxies at z ∼ 6 to 12 still uncertain. Direct detection of LyC photons from this epoch is challenging due to intergalactic medium absorption, making lower-redshift analogs valuable for studying LyC leakage. In this study, we present Hubble Space Telescope Cosmic Origins Spectrograph observations of five low-redshift ( z ∼ 0.3) massive starburst galaxies, selected for high stellar mass and weak [S II ] nebular emission, an indirect tracer of LyC escape. LyC leakage is detected in three of the five galaxies, highlighting weak [S II ] as a reliable tracer—a finding supported by recent JWST discoveries of z > 5 galaxies with similarly weak [S II ] emission. The dust-corrected LyC escape fractions ( f _esc,H _I ), representing LyC photons that would escape without dust, range from 33% to 84%. However, the absolute escape fractions ( f _esc,tot ), accounting for both neutral hydrogen absorption and dust attenuation, are substantially lower, between 1% and 3%. This indicates that, although these galaxies are nearly optically thin to H I , their significant dust content restricts LyC escape. These [S II ]-weak, massive leakers differ from typical low-redshift LyC emitters, exhibiting higher metallicity, lower ionization states, greater dust extinction, and higher star formation surface densities. We suggest that feedback-driven winds in these compact starbursts generate ionized channels, allowing LyC escape in line with a “picket-fence” model, indicating a distinct mechanism for LyC leakage.

Galactic outflows provide important feedback effects to regulate the evolution of host galaxies. Two primary diagnostics of outflows are broad and/or blueshifted emission and absorption lines. Even though well-established methods exist to analyze these outflow signatures, connections between them are rarely studied and largely unknown. In this paper, we conduct such a study in a sample of 33 low-redshift starburst galaxies. Their UV absorption lines are detected by the Hubble Space Telescope, and optical emission lines are observed by Keck or the Very Large Telescope. We find that the outflow properties derived from emission and absorption lines are tightly correlated. These include outflow maximum velocity, line width, and radial extent. On average, in the same galaxy, the maximum velocity and line width of outflows measured from emission lines reach only 60%–70% of those from the absorption lines. We also find outflow rates derived from emission lines are consistently lower than those from absorption lines by 0.2–0.5 dex. These findings can be explained by a radial decline in density and a corresponding increase in outflow velocity, combined with the fact that emission line luminosity scales with the square of the density while absorption line depth scales linearly. We test both spherical and biconical outflow models and find that the same radial outflow velocity and density distributions can explain the observed correlations. These results provide novel calibration between galactic outflow properties measured from the two diagnostics and underscore the need for high-fidelity UV and optical spectra to accurately assess galactic feedback effects in high- z galaxies.

Supernovae (SNe) enrich and energize the surrounding interstellar medium (ISM) and are a key mechanism in the galaxy feedback cycle. The heating of the ISM by supernova shocks and its subsequent cooling is of critical importance to future star formation. The cooling of the diffuse shock-heated ISM is dominated by ultraviolet (UV) emission lines. These cooling regions and interfaces have complex spatial structure on sub-parsec scales. Mapping this cooling process is an essential part of understanding the feedback cycle of galaxies, a major goal of the 2020 Astrophysics Decadal Survey. The Supernova remnants and Proxies for ReIonization Testbed Experiment (SPRITE) 12U CubeSat Mission will house the first long-slit orbital spectrograph with sub-arcminute angular resolution covering far ultraviolet wavelengths (FUV; 1000 to 1750 angstrom) and access to the Lyman UV (lambda<1216 angstrom). SPRITE is designed to provide new insights into the stellar feedback that drives galaxy evolution by mapping key FUV emission lines at the interaction lines between supernova remnants (SNRs) and the ambient ISM. SPRITE will also measure the ionizing escape from similar to 50 low-redshift (0.16 < z < 0.4 ) star-forming galaxies. Current models predict SPRITE capable of detecting strong O VI, O IV], and C IV emission lines with angular resolution from 10 to 20 arcseconds. The SPRITE SNR survey will use push-broom mapping of its long-slit on extended sources to produce the first large sample of sub-arcminute 3D data cubes of extended sources in the FUV. We present simulated SPRITE observations of Large Magellanic Cloud (LMC) SNRs to demonstrate the efficacy of the SPRITE instrument ahead of launch and instrument commissioning. These models serve as critical planning tools and incorporate the final pre-flight predicted performance of the instrument and the early extended source data reduction pipeline.

We present the Cosmic Evolution Early Release Science (CEERS) Survey, a 77.2 hr Director’s Discretionary Early Release Science Program. CEERS demonstrates, tests, and validates efficient extragalactic surveys using coordinated, overlapping parallel observations with the JWST instrument suite, including NIRCam and MIRI imaging, NIRSpec low- ( R ∼ 100) and medium- ( R ∼ 1000) resolution spectroscopy, and NIRCam slitless grism ( R ∼ 1500) spectroscopy. CEERS targets the Hubble Space Telescope–observed region of the Extended Groth Strip field, supported by a rich set of multiwavelength data. CEERS facilitated immediate community science in both of the extragalactic core JWST science drivers “First Light” and “Galaxy Assembly,” including: (1) the discovery and characterization of large samples of galaxies at z ≳ 10 from ∼90 arcmin ^2 of NIRCam imaging, constraining their abundance and physical nature; (2) deep spectra of >1000 galaxies, including dozens of galaxies at 6 < z < 10, enabling redshift measurements and constraints on the physical conditions of star formation and black hole growth via line diagnostics; (3) quantifying the first bulge, bar, and disk structures at z > 3; and (4) characterizing galaxy mid-IR emission with MIRI to study dust-obscured star formation and supermassive black hole growth at z ∼ 1–3. As a legacy product for the community, the CEERS team has provided several data releases, accompanied by detailed notes on the data reduction procedures and notebooks to aid in reproducibility. In addition to an overview of the survey and the quality of the data, we provide science highlights from the first two years with CEERS data.

We performed spectroscopic analyses of five local compact star-forming galaxies (CSFGs) with extremely high [O iii ]/[O ii ] (O _32 ) ratios (>20). These targets remarkably share similar properties with high-redshift C iv emitters at z > 6: high H β equivalent widths (EWs > 200Å), extreme O _32 ratios, low metallicities (12+log(O/H) ≲ 7.8), low C/O abundances (log(C/O) < −0.7), and high ionization conditions (log U > −2). The ultraviolet (UV) spectra were acquired using the Hubble Space Telescope’s (HST) Cosmic Origins Spectrograph and Space Telescope Imaging Spectrograph. We have identified a wealth of rest-frame UV emission lines (C iv , He ii , O iii ], C iii ]) in the HST spectra. Notably, all our targets show intense C iv emission lines with rest-frame EWs > 10 Å, indicative of hard ionizing radiation. The rest-frame UV emission line diagnostics disfavor an active galactic nucelus and could be consistent with significant shock contributions to the source of ionizing radiation. Four of our targets show high C iv /C iii ] ratios (≥1.4), suggestive of strong Lyman-continuum leakage (LyC escape fraction, f _esc,LyC > 10%) from these sources. This is consistent with their Ly α -inferred LyC escape fractions ( f _esc,LyC = 9%–31%). We derive relative C/O abundances from our sources, showing log(C/O) values from −1.28 to −0.77, comparable to those of reionization-era galaxies at z ≳ 6. The properties of the CSFGs, particularly their intense C iv emission and high O _32 ratios, which suggest significant LyC escape fractions, are similar to those of the reionization-era C iv emitters. These similarities reinforce the hypothesis that these CSFGs are the closest analogs of significant contributors to the reionization of the intergalactic medium.

Investigating how small-scale physical processes shape large-scale astrophysical phenomena is one of the key science themes of the Astro2020 decadal Survey. An example of this interplay is Cosmic Reionization, where ionizing photons from galaxies escaped into the intergalactic medium (IGM), driving its transition from neutral to ionized at z>6. Star-forming galaxies are thought to be the dominant sources of reionization. However, an open question remains as to whether bright or faint star-forming galaxies are the primary reionization contributors. This depends on the escape fraction f_ esc^LyC – the fraction of ionizing photons that successfully escape the galaxy's interstellar and circumgalactic medium to reach the IGM. Performing direct measurements of f_ esc^LyC during the reionization epoch is not feasible, due to the near-zero transmission of the IGM at z≳4. However, by calibrating f_ esc^LyC against indirect indicators (i.e. galaxy properties that correlate with f_ esc^LyC) at lower z, we can estimate its value in galaxies during reionization. Currently, f_ esc^LyC calibrations are mostly limited to ∼ 90 sources brighter M_UV∼ -18 at z∼0.3. Yet, recent models suggest that fainter galaxies (-19<M_UV<-13) may be the major contributors to reionization. Our science goal is to extend f_ esc^LyC calibrations to such faint magnitudes. With the Habitable Worlds Observatory, we aim to achieve a ∼ 20-fold increase in statistical power. Additionally, we plan to reach magnitudes as faint as 1/100 L^* at z∼0.1. Suitable targets will be selected from the upcoming Ultraviolet Explorer (UVEX) survey. Through this science case, we will be able to place robust constraints on the role of faint galaxies in the reionization of the Universe and identify its primary contributors.

We use JWST/NIRISS slitless spectroscopy from the Next Generation Deep Extragalactic Exploratory Public (NGDEEP) Survey to investigate the physical condition of 178 star-forming galaxies at 1.7 < z < 3.4. At these redshifts, the deep NGDEEP NIRISS slitless spectroscopy covers the [OII]lambda lambda 3726,3729, [O III]lambda lambda 4959,5007, H beta and H alpha emission features for galaxies with stellar masses log(M-& lowast;/M-circle dot)greater than or similar to 7, nearly a factor of 100 lower than previous studies. We focus on the [OII]/[OIII] (O-32) ratio which is primarily sensitive to the ionization state and with a secondary dependence on the gas-phase metallicity of the interstellar medium. We find significant (greater than or similar to 5 sigma) correlations between the O-32 ratio and galaxy properties as O-32 increases with decreasing stellar mass, decreasing star formation rate (SFR), increasing specific SFR (sSFR equivalent to SFR/M-*), and increasing equivalent width (EW) of H alpha and H beta. These trends suggest a tight connection between the ionization parameter and these galaxy properties. Galaxies at z similar to 2-3 exhibit a higher O-32 than local normal galaxies with the same stellar masses and SFRs, indicating that they have a higher ionization parameter and lower metallicity than local normal galaxies. In addition, we observe a mild evolutionary trend in the O-32-EW(H beta) relation from z similar to 0 to z greater than or similar to 5, where higher redshift galaxies show increased O-32 and EW, with possibly higher O-32 at fixed EW. We argue that both the enhanced recent star formation activity and the higher star formation surface density may contribute to the increase in O-32 and the ionization parameter.

We use James Webb Space Telescope Near-Infrared Camera Wide Field Slitless Spectroscopy (NIRCam WFSS) and the Near-Infrared spectrograph (NIRSpec) in the Cosmic Evolution Early Release survey to measure rest-frame optical emission-line ratios of 155 galaxies at z > 2. The blind NIRCam grism observations include a sample of galaxies with bright emission lines that were not observed on the NIRSpec masks. We study the changes of the H α , [O III ]/H β , and [Ne III ]/[O II ] emission lines in terms of redshift by comparing to lower-redshift SDSS, CLEAR, and MOSDEF samples. We find a significant (>3 σ ) correlation between [O III ]/H β with redshift, while [Ne III ]/[O II ] has a marginal (2 σ ) correlation with redshift. We compare [O III ]/H β and [Ne III ]/[O II ] to stellar mass and H β SFR. We find that both emission-line ratios have a correlation with H β SFR and an anticorrelation with stellar mass across the redshifts 0 < z < 9. Comparison with MAPPINGS V models indicates that these trends are consistent with lower metallicity and higher ionization in low-mass and high-SFR galaxies. We additionally compare to IllustrisTNG predictions and find that they effectively describe the highest [O III ]/H β ratios observed in our sample, without the need to invoke MAPPINGS models with significant shock ionization components.

We present the Next Generation Deep Extragalactic Exploratory Public (NGDEEP) Survey, a deep slitless spectroscopic and imaging Cycle 1 JWST treasury survey designed to constrain feedback mechanisms in low-mass galaxies across cosmic time. NGDEEP targets the Hubble Ultra Deep Field (HUDF) with NIRISS slitless spectroscopy (f~1.2e-18 erg/s/cm^2, 5sigma) to measure metallicities and star-formation rates (SFRs) for low-mass galaxies through the peak of the cosmic SFR density (0.512, constraining the slope of the faint-end of the rest-ultraviolet luminosity function. NGDEEP overlaps with the deepest HST ACS optical imaging in the sky: F435W in the HUDF (m=29.6), and F814W in HUDF-Par2 (m=30), making this a premier HST+JWST Deep Field. As a treasury survey, NGDEEP data is public immediately, and we will rapidly release data products and catalogs in the spirit of previous deep field initiatives. In this paper we present the NGDEEP survey design, summarize the science goals, and detail plans for the public release of NGDEEP reduced data products.

The SPRITE (The Supernova remnants, Proxies for Re-Ionization Testbed Experiment) 12U CubeSat mission, funded by NASA and led by the Laboratory for Atmospheric and Space Physics (LASP) at the University of Colorado Boulder, will house the first Far-UV (100-175 nm) long-slit spectrograph with access to the Lyman UV (λ ⪅ 115 nm) and sub-arcminute imaging resolution. SPRITE will map the high energy emission from diffuse gas allowing for the study of star formation feedback in a critical, but rarely studied, Far-UV regime on both stellar and galactic scales. This novel capability is enabled by new UV technologies incorporated into SPRITE’s design. These technologies include more robust, high broadband reflectivity mirror coatings and an ultra-low background photon counting microchannel plate detector. The SPRITE science mission includes weekly calibration observations to characterize the performance of these key UV technologies over time, increasing their technology readiness level (TRL) to 7+ and providing flight heritage essential for future UV flagship space missions such as the Habitable Worlds Observatory (HWO). Currently, SPRITE is in the beginning stages of integration and testing of its flight assembly with a planned delivery date of fall of 2024. This proceeding will overview the current mission status, the schedule for testing and integration prior to launch, and the planned mission operations for SPRITE.

The geometry of the neutral gas in and around galaxies is a key regulator of the escape of ionizing photons. We present the first statistical study aiming at linking the neutral and ionized gas distributions to the Lyman continuum (LyC) escape fraction (f(esc)((LyC))) in a sample of 22 confirmed LyC leakers and non-leakers at z approximate to 0.35 using the Keck Cosmic Web Imager (Keck/KCWI) and the Low Resolution Spectrograph 2 (HET/LRS2). Our integral field unit data enable the detection of neutral and low-ionization gas, as traced by Mg II, and ionized gas, as traced by [O II], extending beyond the stellar continuum for 7 and 10 objects, respectively. All but one object with extended Mg II emission also shows extended [O II] emission; in this case, Mg II emission is always more extended than [O II] by a factor 1.3 on average. Most of the galaxies with extended emission are non or weak LyC leakers (f(esc)((LyC)) < 5%), but we find a large diversity of neutral gas configurations around these weakly LyC-emitting galaxies. Conversely, the strongest leakers (fesc(LyC) > 10%) appear uniformly compact in both Mg II and [O II] with exponential scale lengths less than or similar to 1 kpc. We also find a trend between f(esc)((LyC)) and the spatial offsets of the nebular gas and the stellar continuum emission. Moreover, we find significant anti-correlations between the spatial extent of the neutral gas and the [O III]/[O II] ratio, and H beta equivalent width, as well as positive correlations with metallicity and UV size, suggesting that galaxies with more compact neutral gas sizes are more highly ionized. The observations suggest that strong LyC emitters do not have extended neutral gas halos and ionizing photons may be emitted in many directions. Combined with high ionization diagnostics, we propose the Mg II, and potentially [O II], spatial compactness are indirect indicators of LyC emitting galaxies at high-redshift.

To understand how galaxies reionized the universe, we must determine how the escape fraction of Lyman Continuum (LyC) photons (fesc) depends on galaxy properties. Using the z~0.3 Low-redshift Lyman Continuum Survey (LzLCS), we develop and analyze new multivariate predictors of fesc. These predictions use the Cox proportional hazards model, a survival analysis technique that incorporates both detections and upper limits. Our best model predicts the LzLCS fesc detections with a root-mean-square (RMS) scatter of 0.31 dex, better than single-variable correlations. According to ranking techniques, the most important predictors of fesc are the equivalent width (EW) of Lyman-series absorption lines and the UV dust attenuation, which track line-of-sight absorption due to HI and dust. The HI absorption EW is uniquely crucial for predicting fesc for the strongest LyC emitters, which show properties similar to weaker LyC emitters and whose high fesc may therefore result from favorable orientation. In the absence of HI information, star formation rate surface density ($\Sigma_{\rm SFR}$) and [O III]/[O II] ratio are the most predictive variables and highlight the connection between feedback and fesc. We generate a model suitable for z>6, which uses only the UV slope, $\Sigma_{\rm SFR}$, and [O III]/[O II]. We find that $\Sigma_{\rm SFR}$ is more important in predicting fesc at higher stellar masses, whereas [O III]/[O II] plays a greater role at lower masses. We also analyze predictions for other parameters, such as the ionizing-to-non ionizing flux ratio and Ly=alpha escape fraction. These multivariate models represent a promising tool for predicting fesc at high redshift.

JWST is uncovering the properties of ever-increasing numbers of galaxies at z > 6, during the epoch of reionization. Connecting these observed populations to the process of reionization requires understanding how efficiently they produce Lyman continuum (LyC) photons and what fraction (f(esc)) of these photons escape into the intergalactic medium. By applying the Cox proportional hazards model, a survival analysis technique, to the Low-redshift Lyman Continuum Survey (LzLCS), we develop new, empirical, multivariate predictions for f(esc). The models developed from the LzLCS reproduce the observed f(esc) for z similar to 3 samples, which suggests that LyC emitters may share similar properties at low and high redshift. Our best-performing models for the z similar to 3 galaxies include information about dust attenuation, ionization, and/or morphology. We then apply these models to z greater than or similar to 6 galaxies. For large photometric samples, we find a median predicted f(esc) = 0.047-0.14. For smaller spectroscopic samples, which may include stronger emission-line galaxies, we find that >= 33% of the galaxies have f(esc) > 0.2, and we identify several candidate extreme leakers with f(esc) >= 0.5. The current samples show no strong trend between predicted f(esc) and UV magnitude, but limited spectroscopic information makes this result uncertain. Multivariate predictions can give significantly different results from single-variable predictions, and the predicted f(esc) for high-redshift galaxies can differ significantly depending on whether star formation rate surface density or radius is used as a measure of galaxy morphology. We provide all parameters necessary to predict f(esc) for additional samples of high-redshift galaxies using these models.

Context. Sources that leak Lyman continuum (LyC) photons and lead to the reionisation of the universe are an object of intense study using multiple observing facilities. Recently, the Low-redshift LyC Survey (LzLCS) has presented the first large sample of LyC emitting galaxies at low redshift (z ∼ 0.3) with the Hubble Space Telescope Cosmic Origins Spectrograph. The LzLCS sample contains a robust estimate of the LyC escape fraction (fescLyC) for 66 galaxies, spanning a wide range of fescLyC values. Aims. Here, we aim to study the dependence of fescLyC on the radio continuum (RC) properties of LzLCS sources. Overall, RC emission can provide unique insights into the role of supernova feedback, cosmic rays (CRs), and magnetic fields from its non-thermal emission component. RC emission is also a dust-free tracer of the star formation rate (SFR) in galaxies. Methods. In this study, we present Karl G. Jansky Very Large Array (VLA) RC observations of the LzLCS sources at gigahertz (GHz) frequencies. We performed VLA C (4−8 GHz) and S (2−4 GHz) band observations for a sample of 53 LzLCS sources. We also observed a sub-sample of 17 LzLCS sources in the L (1−2 GHz) band. We detected RC from both C- and S-bands in 24 sources for which we are able to estimate their radio spectral index across 3−6 GHz, denoted as α6 GHz3 GHz. We also used the RC luminosity to estimate their SFRs. Results. The radio spectral index of LzLCS sources spans a wide range, from flat (≥ − 0.1) to very steep (≤ − 1.0). They have a steeper mean α6 GHz3 GHz (≈ − 0.92) compared to that expected for normal star-forming galaxies (α6 GHz3 GHz ≈ −0.64). They also show a larger scatter in α6 GHz3 GHz (∼0.71) compared to that of normal star-forming galaxies (∼0.15). The strongest leakers in our sample show flat α6 GHz3 GHz, weak leakers have α6 GHz3 GHz close to normal star-forming galaxies and non-leakers are characterized by steep α6 GHz3 GHz. We argue that a combination of young ages, free-free absorption, and a flat cosmic-ray energy spectrum can altogether lead to a flat α6 GHz3 GHz for strong leakers. Non-leakers are characterized by steep spectra which can arise due to break or cutoff at high frequencies. Such a cutoff in the spectrum can arise in a single injection model of CRs characteristic of galaxies which have recently stopped star-formation. The dependence of fescLyC on α6 GHz3 GHz (which is orientation-independent) suggests that the escape of LyC photons is not highly direction-dependent at least to the first order. The radio-based SFRs (SFRRC) of LzLCS sources show a large offset (∼0.59 dex) from the standard SFRRC calibration. We find that adding α6 GHz3 GHz as a second parameter helps us to calibrate the SFRRC with SFRUV and SFRHβ within a scatter of ∼0.21 dex. Conclusions. For the first time, we have found a relation between α6 GHz3 GHz and fescLyC. This hints at the interesting role of supernovae feedback, CRs, and magnetic fields in facilitating the escape (alternatively, and/or the lack) of LyC photons.