def mag_cols_only(cols):
    """
    Returns only the columns names of the magnitudes by excluding columns with "e_" in it.

    :param cols: A list with all column names
    :type cols: list
    :return: A list with the magnitude names only
    :rtype: list
    """
    out = []
    for c in cols:
        if 'e_' not in c:
            out.append(c)
    return out
