We present 6 cm Very Large Array observations of the Greene & Ho sample of 19 low-mass active galaxies with high accretion rates. This is one of the only studies of a uniform sample of narrow-line Seyfert 1 (NLS1) galaxies with such high sensitivity and resolution. Although we detect only one source, the entire sample is very radio quiet down to strong limits. GH 10 was found to have a radio power of 8.5 x 10~(21) WHz~(-1) andaratio R ≡ f_(6 cm)/f_(4400 A) of 2.8. The 3 σ upper limits for the remaining nondetections correspond to radio powers from 3 x 10~(20) to 8 x 10~(21) W Hz~(-1) and 0.47 < R < 9.9. Stacking all nondetections yields an even stronger upper limit of R ≤ 0.27. An assessment of existing observations in the literature confirms our finding that NLS 1 s are consistently radio-quiet, with a radio-loud fraction of 0%-6%, which is significantly lower than the 10%-20% observed in the general quasar population. By analogy with stellar mass black holes, we argue that AGNs undergo a state transition at L_(bol)/L_(Edd) ≈ 0.01. Below this value a radiatively inefficient accretion flow effectively drives an outflow, which disappears when the flow turns into an optically thick, geometrically thin disk, or a radiation pressure-dominated slim disk at still higher L_(bol)/L_(Edd).
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机译：我们对19个具有高吸积率的低质量活跃星系的Greene和Ho样本进行6厘米超大型阵列观测。这是对具有如此高的灵敏度和分辨率的窄线赛弗1（NLS1）星系的均匀样本的唯一研究之一。尽管我们仅检测到一个源，但整个样本在非常低的范围内都是非常安静的无线电。发现GH 10的无线电功率为8.5 x 10〜（21）WHz〜（-1），其比R≡f_（6 cm）/ f_（4400 A）为2.8。其余未检测到的3σ上限对应于从3 x 10〜（20）到8 x 10〜（21）W Hz〜（-1）的无线电功率，且0.47 展开▼
