TY - JOUR
T1 - LEO P
T2 - HOW MANY METALS CAN A VERY LOW MASS, ISOLATED GALAXY RETAIN?
AU - McQuinn, Kristen B.W.
AU - Skillman, Evan D.
AU - Dolphin, Andrew
AU - Cannon, John M.
AU - Salzer, John J.
AU - Rhode, Katherine L.
AU - Adams, Elizabeth A.K.
AU - Berg, Danielle
AU - Giovanelli, Riccardo
AU - Haynes, Martha P.
N1 - Publisher Copyright:
© 2015. The American Astronomical Society. All rights reserved.
PY - 2015/12/20
Y1 - 2015/12/20
N2 - Leo P is a gas-rich dwarf galaxy with an extremely low gas-phase oxygen abundance (3% solar). The isolated nature of Leo P enables a quantitative measurement of metals lost solely due to star formation feedback. We present an inventory of the oxygen atoms in Leo P based on the gas-phase oxygen abundance measurement, the star formation history (SFH), and the chemical enrichment evolution derived from resolved stellar populations. The SFH also provides the total amount of oxygen produced. Overall, Leo P has retained 5% of its oxygen; 25% of the retained oxygen is in the stars while 75% is in the gas phase. This is considerably lower than the 20%-25% calculated for massive galaxies, supporting the trend for less efficient metal retention for lower-mass galaxies. The retention fraction is higher than that calculated for other alpha elements (Mg, Si, Ca) in dSph Milky Way satellites of similar stellar mass and metallicity. Accounting only for the oxygen retained in stars, our results are consistent with those derived for the alpha elements in dSph galaxies. Thus, under the assumption that the dSph galaxies lost the bulk of their gas mass through an environmental process such as tidal stripping, the estimates of retained metal fractions represent underestimates by roughly a factor of four. Because of its isolation, Leo P provides an important datum for the fraction of metals lost as a function of galaxy mass due to star formation.
AB - Leo P is a gas-rich dwarf galaxy with an extremely low gas-phase oxygen abundance (3% solar). The isolated nature of Leo P enables a quantitative measurement of metals lost solely due to star formation feedback. We present an inventory of the oxygen atoms in Leo P based on the gas-phase oxygen abundance measurement, the star formation history (SFH), and the chemical enrichment evolution derived from resolved stellar populations. The SFH also provides the total amount of oxygen produced. Overall, Leo P has retained 5% of its oxygen; 25% of the retained oxygen is in the stars while 75% is in the gas phase. This is considerably lower than the 20%-25% calculated for massive galaxies, supporting the trend for less efficient metal retention for lower-mass galaxies. The retention fraction is higher than that calculated for other alpha elements (Mg, Si, Ca) in dSph Milky Way satellites of similar stellar mass and metallicity. Accounting only for the oxygen retained in stars, our results are consistent with those derived for the alpha elements in dSph galaxies. Thus, under the assumption that the dSph galaxies lost the bulk of their gas mass through an environmental process such as tidal stripping, the estimates of retained metal fractions represent underestimates by roughly a factor of four. Because of its isolation, Leo P provides an important datum for the fraction of metals lost as a function of galaxy mass due to star formation.
KW - galaxies: abundances
KW - galaxies: dwarf
KW - galaxies: evolution
KW - galaxies: stellar content
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U2 - 10.1088/2041-8205/815/2/L17
DO - 10.1088/2041-8205/815/2/L17
M3 - Article
AN - SCOPUS:84951858312
SN - 2041-8205
VL - 815
JO - Astrophysical Journal Letters
JF - Astrophysical Journal Letters
IS - 2
M1 - L17
ER -