User can select authors from user preferences

function select_authors_fields( $user ) {
    $authors = get_users();
	$user_tags = get_the_author_meta( 'select_authors', $user->ID );
    ?>
    <table class="form-table">
        <tr>
            <th>Select authors:</th>
            <td>
        <?php
        if ( count( $authors ) ) {
            foreach ($authors as $author) {
				 if (user_can($author->ID, 'publish_posts')) { ?>
            <p><label for="select_authors_<?php echo esc_attr( $author->ID); ?>">
                <input
                    id="select_authors_<?php echo esc_attr( $author->ID); ?>"
                    name="select_authors[<?php echo esc_attr( get_the_author_meta('display_name', $author->ID) ); ?>]"
                    type="checkbox"
                    value="<?php echo esc_attr( get_the_author_meta('ID', $author->ID) ); ?>"
                    <?php if ( in_array( get_the_author_meta('ID', $author->ID), $user_tags ) ) echo ' checked="checked"'; ?> />
                <?php echo esc_html(get_the_author_meta('display_name', $author->ID)); ?>
            </label></p><?php
				 }
			 }
        } ?>
            </td>
        </tr>
    </table>
    <?php
		}
add_action( 'show_user_profile', 'select_authors_fields' );
add_action( 'edit_user_profile', 'select_authors_fields' );

    // store authors
    function select_authors_fields_save( $user_id ) {
        if ( !current_user_can( 'edit_user', $user_id ) )
            return false;
        update_user_meta( $user_id, 'select_authors', $_POST['select_authors'] );
	}
    add_action( 'personal_options_update', 'select_authors_fields_save' );
    add_action( 'edit_user_profile_update', 'select_authors_fields_save' );

Now the author list appears with checkboxes and it saves my selections. How do I write the query to show the posts from authors I have selected?

function my_get_posts( $query ) {
    if ( !is_user_logged_in() ) return;
    $current_user = wp_get_current_user();

    $authors = get_user_meta( $current_user->ID, 'select_authors', true );
	echo $authors;
	//$query = new WP_Query( 'author_name=' .$authors );
	return $query;
}
add_filter( 'pre_get_posts', 'my_get_posts' );

If I only echo $authors it prints many Arrays. Someone?