wp.media events list

Hi,
I’m developing a gallery and this is the JS code for the media library:

jQuery(document).ready(function(){

    var custom_uploader;

    jQuery('#upload_image_button').click(function(e) {

        //forbid default behaviour of the event
        e.preventDefault();

        //If the uploader object has already been created, reopen the dialog
        if (custom_uploader) {
            custom_uploader.open();
            return;
        }

        //Extend the wp.media object to create the window
        custom_uploader = wp.media.frames.file_frame = wp.media({
            title: 'Choose Image',
            button: {
                text: 'Choose Image'
            },
            multiple: false
        });

        //When a file is selected, grab the URL and set it as the text field's value
        custom_uploader.on('select', function() {
            // Get media attachment details from the frame state
            attachment = custom_uploader.state().get('selection').first().toJSON();
            jQuery('#upload_image').val(attachment.url);
        });

        //Open the uploader dialog
        custom_uploader.open();

    });

});

Now I need to get the image ID to arrange images from the media library which will take part on the gallery using PHP so I thought an AJAX/JSON call should be good to pass data from the media window created with wp.media after the user clicks on “Choose image”.

How can I get this event?
I cant’ find a list of events associated to wp.media but in the code above there’s:

custom_uploader.on('select', function() {...}

so I think there could be a sort of custom_uploader.on(‘buttonclick’ function(){…}, isn’t it?

Otherwise how can I accomplish it?

Thank you!