We present high-resolution radio-continuum observations of the nascent starburst in the metal-poor galaxy SBS?0335–052. These radio data were taken with the Very Large Array and include observations at 0.7 cm, 1.3 cm, 2 cm, 3.6 cm, and 6 cm. These observations enable us to probe the thermal radio nebulae associated with the extremely young star-forming regions in this galaxy. Two discrete and luminous star-forming regions are detected in the south of the galaxy that appear to be associated with massive star clusters previously identified at optical wavelengths. However, the remaining optically identified massive star clusters are not clearly associated with radio emission (either thermal or nonthermal) down to the sensitivity limits of these radio data. The spectral energy distributions (SEDs) of the two radio-detected clusters are consistent with being purely thermal, and the entire region has an inferred ionizing flux of ~1.2 × 1053 s–1, which is equivalent to ~12,000 "typical" O-type stars (type O7.5?V). The observations presented here have resolved out a significant contribution from diffuse nonthermal emission detected previously, implying a previous episode of significant star formation. The current star formation rate (SFR) for this southern region alone is ~1.3 M ☉ yr–1, or ~23 M ☉ yr–1 kpc–2, which is nearing the maximum starburst intensity limit. This SFR derived from thermal radio emission also suggests that previous optical recombination line studies do not detect a significant fraction of the current star formation in SBS?0335–052. From model fits to the radio SED, we infer a global mean density in the two youngest clusters of ne 103-104 cm–3. In addition, a comparison between the compact and diffuse radio emission indicates that up to ~50% of the ionizing flux could be leaking out of the compact H?II regions; this in is agreement with previous work, which suggests that the interstellar medium surrounding the natal clusters in SBS?0335–052 is porous and clumpy.
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机译：我们提供了贫金属星系SBS？0335–052中新生的星爆的高分辨率无线电连续观测。这些无线电数据是使用超大型阵列采集的，包括在0.7 cm，1.3 cm，2 cm，3.6 cm和6 cm处的观测值。这些观测使我们能够探测与该星系中极年轻的恒星形成区域有关的热辐射星云。在银河系的南部发现了两个离散且发光的恒星形成区域，这些区域似乎与先前在光波长处识别出的巨大恒星团有关。但是，剩下的光学识别的大质量恒星团并没有清晰地与无线电发射（热的或非热的）下降到这些无线电数据的灵敏度极限相关。两个被放射性检测到的簇的光谱能量分布（SED）与纯热一致，并且整个区域的推断电离通量约为1.2×1053 s-1，相当于〜12,000“典型” O-星型（O7.5？V型）。此处介绍的观测结果已解决了先前检测到的弥散性非热辐射的重大贡献，这意味着先前发生了明显的恒星形成。仅此南部地区的当前恒星形成率（SFR）约为1.3 M☉yr-1，或〜23 M k yr-1 kpc-2，接近最大爆炸爆发强度极限。该源自热辐射发射的SFR还表明，先前的光重组线研究并未发现SBS？0335–052中当前恒星形成的大部分。从模型拟合到无线电SED，我们推断ne-103-104 cm-3的两个最年轻簇中的全球平均密度。另外，紧凑型和扩散型无线电发射之间的比较表明，高达〜50％的电离通量可能会泄漏出紧凑型H2II区域。这与以前的工作是一致的，这表明围绕SBS？0335–052中的新生代簇的星际介质是多孔且结块的。
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