TY - JOUR
T1 - Q1549-C25
T2 - A CLEAN SOURCE of LYMAN-CONTINUUM EMISSION at z < 3.15
AU - Shapley, Alice E.
AU - Steidel, Charles C.
AU - Strom, Allison L.
AU - Bogosavljević, Milan
AU - Reddy, Naveen A.
AU - Siana, Brian
AU - Mostardi, Robin E.
AU - Rudie, Gwen C.
N1 - Publisher Copyright:
© 2016. The American Astronomical Society. All rights reserved.
PY - 2016/8/1
Y1 - 2016/8/1
N2 - We present observations of Q1549-C25, an L∗star-forming galaxy at z<3.15 for which Lyman-continuum (LyC) radiation is significantly detected in deep Keck/LRIS spectroscopy. We find no evidence of contamination from a lower-redshift interloper close to the line of sight in the high signal-to-noise spectrum of Q1549-C25. Furthermore, the morphology of Q1549-C25 in V606, J125, and H160 Hubble Space TelESCope (HST) imaging reveals that the object consists of a single, isolated component within 1?. In combination, these data indicate Q1549-C25 as a clean spectroscopic detection of LyC radiation, only the second such object discovered to date at Z3. We model the spectral energy distribution of Q1549-C25, finding evidence of negligible dust extinction, an age (assuming continuous star formation) of1 Gyr, and a stellar mass of M∗< 7.9 109 M⊙. Although it is not possible to derive strong constraints on the absolute ESCape fraction of LyC emission, fESC(LyC), from a single object, we use simulations of intergalactic and circumgalactic absorption to infer fESC (LyC) ≥ 0.51 at 95% confidence. The combination of deep Keck/LRIS spectroscopy and Hubble Space TelESCope imaging is required to assemble a larger sample of objects like Q1549-C25, and obtain robust constraints on the average fESC(LyC) at z 3 and beyond.
AB - We present observations of Q1549-C25, an L∗star-forming galaxy at z<3.15 for which Lyman-continuum (LyC) radiation is significantly detected in deep Keck/LRIS spectroscopy. We find no evidence of contamination from a lower-redshift interloper close to the line of sight in the high signal-to-noise spectrum of Q1549-C25. Furthermore, the morphology of Q1549-C25 in V606, J125, and H160 Hubble Space TelESCope (HST) imaging reveals that the object consists of a single, isolated component within 1?. In combination, these data indicate Q1549-C25 as a clean spectroscopic detection of LyC radiation, only the second such object discovered to date at Z3. We model the spectral energy distribution of Q1549-C25, finding evidence of negligible dust extinction, an age (assuming continuous star formation) of1 Gyr, and a stellar mass of M∗< 7.9 109 M⊙. Although it is not possible to derive strong constraints on the absolute ESCape fraction of LyC emission, fESC(LyC), from a single object, we use simulations of intergalactic and circumgalactic absorption to infer fESC (LyC) ≥ 0.51 at 95% confidence. The combination of deep Keck/LRIS spectroscopy and Hubble Space TelESCope imaging is required to assemble a larger sample of objects like Q1549-C25, and obtain robust constraints on the average fESC(LyC) at z 3 and beyond.
KW - Cosmology: Observations
KW - Diffuse radiation
KW - Galaxies: High-redshift
KW - Intergalactic Medium
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U2 - 10.3847/2041-8205/826/2/L24
DO - 10.3847/2041-8205/826/2/L24
M3 - Article
AN - SCOPUS:84982270112
SN - 2041-8205
VL - 826
JO - Astrophysical Journal Letters
JF - Astrophysical Journal Letters
IS - 2
M1 - L24
ER -