TY - JOUR
T1 - Spectral energy distribution of the first galaxies
T2 - Contribution from pre-main-sequence stars
AU - Mitani, Hiroto
AU - Yoshida, Naoki
AU - Omukai, Kazuyuki
AU - Hosokawa, Takashi
N1 - Funding Information:
NY thanks K. Shimasaku for fruitful discussion. NY acknowledges the financial support from Japan Science and Technology Agency CREST JPMHCR1414. This work was supported by Japan Society for the Promotion of Science KAKENHI Grant number JP16H05996, JP17H06360, JP17H01102, and JP17H02869.
Publisher Copyright:
© 2019 The Author(s) Published by Oxford University Press on behalf of the Royal Astronomical Society.
PY - 2019/9/1
Y1 - 2019/9/1
N2 - One of the major goals of next-generation space-borne and ground-based telescopes is to detect and characterize the first galaxies that were in place in the first few hundred million years after the big bang. We study the spectral energy distribution (SED) of the first galaxies and discuss the prospects for detection and identification. We consider very young star-forming galaxies at z = 15 and incorporate the contribution from pre-main-sequence (PMS) stars. Unlike in the present-day galaxies, primordial protostars are not embedded in dusty gas clouds, and hence the light from them can be visible at a wide range of wavelengths. We use mesa to follow the PMS evolution and use the BT-Settl model to calculate the SED of individual PMS stars. We show that PMS stars contribute to boost the flux in the mid-infrared, and that the galaxy SED at very early evolutionary phases is overall redder than at later phases. The infrared flux contribution is comparable to that caused by emission lines powered by massive stars. We argue that the contribution from PMS stars is important for characterizing young galaxies in the early Universe and also for target selection with future deep galaxy surveys.
AB - One of the major goals of next-generation space-borne and ground-based telescopes is to detect and characterize the first galaxies that were in place in the first few hundred million years after the big bang. We study the spectral energy distribution (SED) of the first galaxies and discuss the prospects for detection and identification. We consider very young star-forming galaxies at z = 15 and incorporate the contribution from pre-main-sequence (PMS) stars. Unlike in the present-day galaxies, primordial protostars are not embedded in dusty gas clouds, and hence the light from them can be visible at a wide range of wavelengths. We use mesa to follow the PMS evolution and use the BT-Settl model to calculate the SED of individual PMS stars. We show that PMS stars contribute to boost the flux in the mid-infrared, and that the galaxy SED at very early evolutionary phases is overall redder than at later phases. The infrared flux contribution is comparable to that caused by emission lines powered by massive stars. We argue that the contribution from PMS stars is important for characterizing young galaxies in the early Universe and also for target selection with future deep galaxy surveys.
KW - galaxies: evolution
KW - stars: Population III
KW - stars: pre-main-sequence
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U2 - 10.1093/mnrasl/slz100
DO - 10.1093/mnrasl/slz100
M3 - Article
AN - SCOPUS:85084295215
VL - 488
SP - L64-L68
JO - Monthly Notices of the Royal Astronomical Society: Letters
JF - Monthly Notices of the Royal Astronomical Society: Letters
SN - 1745-3925
IS - 1
ER -