Galaxy bulges and their black holes: a requirement for the quenching of star formation

One of the central features of the last 8 to 10 billion years of cosmic history has been the emergence of a well-populated red sequence of non-star-forming galaxies. A number of models of galaxy formation and evolution have been devised to attempt to explain this behavior. Most current models require feedback from supermassive black holes (AGN feedback) to quench star formation in galaxies in the centers of their dark matter halos (central galaxies). Such models make the strong prediction that all quenched central galaxies must have a large supermassive black hole (and, by association, a prominent bulge component). I show using data from the Sloan Digital Sky Survey that the observations are consistent with this prediction. Over 99.5% of red sequence galaxies with stellar masses in excess of 10^{10} M_{\sun} have a prominent bulge component (as defined by having a Sersic index n above 1.5). Those very rare red sequence central galaxies with little or no bulge (n<1.5) usually have detectable star formation or AGN activity; the fraction of truly quenched bulgeless central galaxies is <0.1% of the total red sequence population. I conclude that a bulge, and by implication a supermassive black hole, is an absolute requirement for full quenching of star formation in central galaxies. This is in agreement with the most basic prediction of the AGN feedback paradigm.Comment: 6 pages, 4 color figures (figure 1 is of slightly degraded quality). To appear in August 1 edition of the Astrophysical Journa

Study of thin film large area photovoltaic solar energy converter First quarterly report, 25 Oct. 1965 - 24 Jan. 1966

Cadmium sulfide thin film photovoltaic cell for large area solar energy converte

Development of cadmium sulfide thin film photovoltaic cells third quarterly report, apr. 15 - jul. 14, 1965

Cadmium sulfide thin film photovoltaic cells - cadmium sulfide film evaporation, cell testing, improvement, and stability, and plastic and metal substrate cell

Study of thin film large area photovoltaic solar energy converter Second quarterly report, 25 Feb. - 24 May 1966

Cadmium sulfide thin film solar cell developmen

Study of thin film large area photovoltaic solar energy converter Final report

Thin film large area cadmium sulfide solar cell

Study of thin film large area photovoltaic solar energy converter Third quarterly report, 25 Apr. - 24 Jul. 1966

Cadmium sulfide-thin film large area photovoltaic solar energy converter - plastic substrate cell fabrication and stability testing under various conditions of temperature and humidit

CdS solar cell development Interim technical report

Cadmium sulfide solar cell design criteri

CdS solar cell development Final report

Plastic substrate, cadmium sulfide thin film solor cel