Context : The study of statistically significant samples of star-forming dwarf galaxies ( SFDGs ) at different cosmic epochs is essential for the detailed understanding of galaxy assembly and chemical evolution .
However , the main properties of this numerous population of galaxies at intermediate redshift are still poorly known .

Aims : We present the discovery and spectrophotometric characterization of a large sample of 164 faint ( i _ { AB } \sim 23-25 mag ) SFDGs at redshift 0.13 \leq z \leq 0.88 selected by the presence of bright optical emission lines in the VIMOS Ultra Deep Survey ( VUDS ) .
We investigate their integrated physical properties and ionization conditions , which are used to discuss the low-mass end of the mass-metallicity relation ( MZR ) and other key scaling relations .

Methods : We use optical VUDS spectra in the COSMOS , VVDS-02h , and ECDF-S fields , as well as deep multiwavelength photometry which includes HST-ACS F814W imaging , to derive stellar masses , extinction-corrected star formation rates ( SFR ) and gas-phase metallicities of SFDGs .
For the latter , we use the direct method and a T _ { e } -consistent approach based on the comparison of a set of observed emission lines ratios with the predictions of detailed photoionization models .

Results : The VUDS SFDGs are compact ( median r _ { e } \sim 1.2 kpc ) , low-mass ( M _ { * } \sim 10 ^ { 7 } -10 ^ { 9 } M _ { \odot } ) galaxies with a wide range of star formation rates ( SFR ( H \alpha ) \sim 10 ^ { -3 } - 10 ^ { 1 } M _ { \odot } / yr ) and morphologies .
Overall , they show a broad range of subsolar metallicities ( 12 + \log ( O/H ) = 7.26 - 8.7 ; 0.04 \la Z / Z _ { \odot } \la 1 ) .
Nearly half of the sample are extreme emission-line galaxies ( EELGs ) characterized by high equivalent widths and emission line ratios indicative of higher excitation and ionization conditions .
The MZR of SFDGs shows a flatter slope compared to previous studies of galaxies in the same mass range and redshift .
We find the scatter of the MZR partly explained in the low mass range by varying specific SFRs and gas fractions amongst the galaxies in our sample .
In agreement with recent studies , we find the subclass of EELGs to be systematically offset to lower metallicity compared to SFDGs at a given stellar mass and SFR , suggesting a younger starburst phase .
Compared with simple chemical evolution models we find that most SFDGs do not follow the predictions of a ” closed-box ” model , but those from a gas regulating model in which gas flows are considered .
While strong stellar feedback may produce large-scale outflows favoring the cessation of vigorous star formation and promoting the removal of metals , younger and more metal-poor dwarfs may have recently accreted large amounts of fresh , very metal-poor gas , that is used to fuel current star formation .

Conclusions :