Equivalent widths ( EWs ) observed in high-redshift Lyman alpha galaxies could be stronger than the EW intrinsic to the stellar population if dust is present residing in clumps in the inter-stellar medium ( ISM ) .
In this scenario , continuum photons could be extinguished while the Ly \alpha photons would be resonantly scattered by the clumps , eventually escaping the galaxy .
We investigate this radiative transfer scenario with a new sample of six Ly \alpha galaxy candidates in the GOODS CDF-S , selected at z = 4.4 with ground-based narrow-band imaging obtained at CTIO .
Grism spectra from the HST PEARS survey confirm that three objects are at z = 4.4 , and that another object contains an active galactic nuclei ( AGN ) .
If we assume the other five ( non-AGN ) objects are at z = 4.4 , they have rest-frame EWs from 47 – 190 Å .
We present results of stellar population studies of these objects , constraining their rest-frame UV with HST and their rest-frame optical with Spitzer .
Out of the four objects which we analyzed , three objects were best-fit to contain stellar populations with ages on the order of 1 Myr and stellar masses from 3 – 10 \times 10 ^ { 8 } M _ { \odot } , with dust in the amount of A _ { 1200 } = 0.9 – 1.8 residing in a quasi-homogeneous distribution .
However , one object ( with a rest EW \sim 150 Å ) was best fit by an 800 Myr , 6.6 \times 10 ^ { 9 } M _ { \odot } stellar population with a smaller amount of dust ( A _ { 1200 } = 0.4 ) attenuating the continuum only .
In this object , the EW was enhanced \sim 50 % due to this dust .
This suggests that large EW Ly \alpha galaxies are a diverse population .
Preferential extinction of the continuum in a clumpy ISM deserves further investigation as a possible cause of the overabundance of large-EW objects that have been seen in narrow-band surveys in recent years .