Estimates of the integrated (SFR) and specific (sSFR) rates of star formation are given for 181 galaxies of later Sc, Scd, and Sd types seen almost face-on. Their SFRs were determined from FUV fluxes in the GALEX survey. The median values of the sSFR are: -10.66 dex for Sc, -10.44 dex for Scd, and -10.40 dex for Sd types in units of yr-1. The average value of the sSFR for these galaxies falls off smoothly from low-mass to giant disks. After accounting for photometric errors, the specific star formation rate has a small cosmic variation of 0.16 dex. In order to reproduce the observed stellar mass on a cosmic time of 13.8 Gyr, the galaxies without bulges viewed face-on must have had an SFR two-three times higher in the past than observed now.

中文翻译：

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正面看到的螺旋星系薄盘中的恒星形成

估计了恒星形成的综合（SFR）和比（sSFR）速率，估计了 181 个几乎面对面的后期 Sc、Scd 和 Sd 类型的星系。它们的恒星形成率是根据 GALEX 调查中的 FUV 通量确定的。sSFR 的中值为：Sc 的 -10.66 dex，Scd 的 -10.44 dex 和 Sd 类型的 -10.40 dex，以 yr-1 为单位。这些星系的 sSFR 平均值从低质量到巨盘平稳下降。考虑到光度误差后，特定的恒星形成率有一个 0.16 dex 的小宇宙变化。为了在 13.8 Gyr 的宇宙时间重现观测到的恒星质量，正面观察的没有凸起的星系在过去的恒星形成率必须比现在高出两三倍。