TY - JOUR

T1 - Detection of nitrogen and oxygen in a galaxy at the end of reionization

AU - Tadaki, Ken-ichi

AU - Tsujita, Akiyoshi

AU - Tamura, Yoichi

AU - Kohno, Kotaro

AU - Hatsukade, Bunyo

AU - Iono, Daisuke

AU - Lee, Minju M.

AU - Matsuda, Yuichi

AU - Michiyama, Tomonari

AU - Nagao, Tohru

AU - Nakanishi, Kouichiro

AU - Nishimura, Yuri

AU - Saito, Toshiki

AU - Umehata, Hideki

AU - Zavala, Jorge

PY - 2022/6/2

Y1 - 2022/6/2

N2 - We present observations of [N II] 205 mu m, [O III]88 mu m, and dust emission in a stronglylensed, submillimeter galaxy (SMG) at z= 6.0, G09.83808, with the Atacama Large Millimeter/submillimeter Array (ALMA). Both [N II] and [O III] line emissions are detected at >12 sigma in the 0".8-resolution maps. Lens modeling indicates that the spatial distribution of the dust continuum emission is well characterized by a compact disk with an effective radius of 0.64 +/- 0.02 kpc and a high infrared surface brightness of Sigma(IR) = (1.8 +/- 0.3) x 10(12) L-circle dot kpc(-2). This result supports that G09.83808 is the progenitor of compact quiescent galaxies at z similar to 4, where the majority of its stars are expected to be formed through a strong and short burst of star formation. G09.83808 and other lensed SMGs show a decreasing trend in the [N Id line to infrared luminosity ratio with increasing continuum flux density ratio between 63 and 158 mu m, as seen in local luminous infrared galaxies (LIRGs). The decreasing trend can be reproduced by photoionization models with increasing ionization parameters. Furthermore, by combining the [N II]/[O III] luminosity ratio with far-infrared continuum flux density ratio in G09.83808, we infer that the gas phase metallicity is already Z approximate to 0.5-0.7 Z(circle dot). G09.83808 is likely one of the earliest galaxies that has been chemically enriched at the end of reionization.

AB - We present observations of [N II] 205 mu m, [O III]88 mu m, and dust emission in a stronglylensed, submillimeter galaxy (SMG) at z= 6.0, G09.83808, with the Atacama Large Millimeter/submillimeter Array (ALMA). Both [N II] and [O III] line emissions are detected at >12 sigma in the 0".8-resolution maps. Lens modeling indicates that the spatial distribution of the dust continuum emission is well characterized by a compact disk with an effective radius of 0.64 +/- 0.02 kpc and a high infrared surface brightness of Sigma(IR) = (1.8 +/- 0.3) x 10(12) L-circle dot kpc(-2). This result supports that G09.83808 is the progenitor of compact quiescent galaxies at z similar to 4, where the majority of its stars are expected to be formed through a strong and short burst of star formation. G09.83808 and other lensed SMGs show a decreasing trend in the [N Id line to infrared luminosity ratio with increasing continuum flux density ratio between 63 and 158 mu m, as seen in local luminous infrared galaxies (LIRGs). The decreasing trend can be reproduced by photoionization models with increasing ionization parameters. Furthermore, by combining the [N II]/[O III] luminosity ratio with far-infrared continuum flux density ratio in G09.83808, we infer that the gas phase metallicity is already Z approximate to 0.5-0.7 Z(circle dot). G09.83808 is likely one of the earliest galaxies that has been chemically enriched at the end of reionization.

KW - galaxies: high-redshift

KW - galaxies: ISM

KW - galaxies: starburst

KW - STAR-FORMING GALAXIES

KW - SUBMILLIMETER GALAXIES

KW - REDSHIFT DISTRIBUTION

KW - INTERSTELLAR-MEDIUM

KW - BILLION YEARS

KW - DUSTY

KW - EVOLUTION

KW - SPECTROSCOPY

KW - PREDICTIONS

KW - STARBURSTS

U2 - 10.1093/pasj/psac018

DO - 10.1093/pasj/psac018

M3 - Journal article

VL - 74

SP - L9-L16

JO - Publication of the Astronomical Society of Japan

JF - Publication of the Astronomical Society of Japan

SN - 0004-6264

IS - 3

ER -