You are concatenating a jQuery wrapper to a string, that is the reason
without changing much from your code
var side_bar_html = "<a href='javascript:google.maps.event.trigger(gmarkers[" + parseInt(gmarkers.length - 1) + "],\"click\");'>" + place.name + "</a><br>" + '<div class="raty" />' + "</br>";
$(side_bar_html).appendTo('#side_bar').filter('.raty').raty({
score : place.rating,
path : 'http://wbotelhos.com/raty/lib/img'
})