Markarian 501
... that the galaxy Markarian 501 produces very high energy gamma rays?
... that the galaxy <b id="mwBqU"><a href="./Markarian_501" id="mwBqY" rel="mw:WikiLink" title="Markarian 501">Markarian 501</a></b> produces <a class="mw-redirect" href="./Very_high_energy_gamma_ray" id="mwBqc" rel="mw:WikiLink" title="Very high energy gamma ray">very high energy gamma rays</a>?