We report the result from observations conducted with the Atacama Large Millimeter/submillimeter Array ( ALMA ) to detect [ Cii ] 158 \mu m fine structure line emission from galaxies embedded in one of the most spectacular Ly \alpha blobs ( LABs ) at z = 3.1 , SSA22-LAB1 .
Of three dusty star-forming galaxies previously discovered by ALMA 860 \mu m dust continuum survey toward SSA22-LAB1 , we detected the [ Cii ] line from one , LAB1-ALMA3 at z =3.0993 \pm 0.0004 .
No line emission was detected , associated with the other ALMA continuum sources or from three rest-frame UV/optical selected z _ { spec } \simeq 3.1 galaxies within the field of view .
For LAB1-ALMA3 , we find relatively bright [ Cii ] emission compared to the infrared luminosity ( L _ { \textsc { [ Cii ] } } / L _ { IR } \approx 0.01 ) and an extremely high [ Cii ] 158 \mu m and [ Nii ] 205 \mu m emission line ratio ( L _ { \textsc { [ Cii ] } } / L _ { \textsc { [ Nii ] } } > 55 ) .
The relatively strong [ Cii ] emission may be caused by abundant photodissociation regions and sub-solar metallicity , or by shock heating .
The origin of the unusually strong [ Cii ] emission could be causally related to the location within the giant LAB , although the relationship between extended Ly \alpha emission and ISM conditions of associated galaxies is yet to be understand .