not able to select topic in rviz

edit

I started with introduction to working with laserscanner data tutorials:

as it says i executed the following commands in terminal:

roscore in a terminal

then again

$ rosbag play laser.bag[ INFO] [1331111093.757680745]: Opening laser.bag

Waiting 0.2 seconds after advertising topics... done.

Hit space to toggle paused, or 's' to step.
 [RUNNING]  Bag Time: 1275001525.634246   Duration: 41.420635 / 41.431989    
Done.
root@arun-Dell-System-Inspiron-N4110:~# rostopic list -v | grep sensor_msgs/LaserScan
root@arun-Dell-System-Inspiron-N4110:~# rosrun rviz rviz

in rviz i could not find the laserscan or /tilt_scan topic. i have inserted the rviz i got after rosrun rviz rviz

can anyone tell me why i'm not able to see the topics list and visualize laserdata in rviz