We present deep radio continuum observations of the cores identified as deeply embedded young stellar objects in the Serpens molecular cloud by the Spitzer c2d programme at a wavelength of 1.8 cm with the Arcminute Microkelvin Imager Large Array ( AMI-LA ) .
These observations have a resolution of \approx 30 arcsec and an average sensitivity of 19 \mu Jy beam ^ { -1 } .
The targets are predominantly Class I sources , and we find the detection rate for Class I objects in this sample to be low ( 18 % ) compared to that of Class 0 objects ( 67 % ) , consistent with previous works .
For detected objects we examine correlations of radio luminosity with bolometric luminosity and envelope mass and find that these data support correlations found by previous samples , but do not show any indiction of the evolutionary divide hinted at by similar data from the Perseus molecular cloud when comparing radio luminosity with envelope mass .
We conclude that envelope mass provides a better indicator for radio luminosity than bolometric luminosity , based on the distribution of deviations from the two correlations .
Combining these new data with archival 3.6 cm flux densities we also examine the spectral indices of these objects and find an average spectral index of \bar { \alpha } _ { 3.5 } ^ { 1.8 } = 0.53 \pm 1.14 , consistent with the canonical value for a partially optically thick spherical or collimated stellar wind .
However , we caution that possible inter-epoch variability limits the usefulness of this value , and such variability is supported by our identification of a possible flare in the radio history of Serpens SMM 1 .