JWST NIRSpec High-resolution Spectroscopy of MACS0647–JD at z = 10.167: Resolved [O ii] Doublet and Electron Density in an Early Galaxy
Abstract We present JWST/NIRSpec high-resolution G395H/F290LP spectroscopy of MACS0647−JD, a gravitationally lensed galaxy merger at z = 10.167. The new spectroscopy, which is acquired for the two lensed images (JD1 and JD2), detects and resolves emission lines in the rest-frame ultraviolet and blue optical, including the resolved [O ii ] λ λ 3726, 3729 doublet, [Ne iii ] λ 3870, He i λ 3890, H δ , H γ , and [O iii ] λ 4363. This is the first observation of the resolved [O ii ] λ λ 3726, 3729 doublet for a galaxy at z > 8. We measure a line flux ratio [O ii ] λ 3729/ λ 3726 = 0.9 ± 0.3, which corresponds to an estimated electron density of <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" overflow="scroll"> <mml:mi>log</mml:mi> <mml:mo stretchy="false">(</mml:mo> <mml:msub> <mml:mrow> <mml:mi>n</mml:mi> </mml:mrow> <mml:mrow> <mml:mi>e</mml:mi> </mml:mrow> </mml:msub> <mml:mrow> <mml:mo stretchy="true">/</mml:mo> </mml:mrow> <mml:msup> <mml:mrow> <mml:mi>cm</mml:mi> </mml:mrow> <mml:mrow> <mml:mo>−</mml:mo> <mml:mn>3</mml:mn> </mml:mrow> </mml:msup> <mml:mo stretchy="false">)</mml:mo> <mml:mo>=</mml:mo> <mml:mn>2.9</mml:mn> <mml:mo>±</mml:mo> <mml:mn>0.5</mml:mn> </mml:math> . This is significantly higher than the electron densities of local galaxies reported in the literature. We compile measurements from the literature and further analyze the redshift evolution of n e . We find that the redshift evolution follows the power-law form of n e = A × (1 + z ) p with <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" overflow="scroll"> <mml:mi>A</mml:mi> <mml:mo>=</mml:mo> <mml:msubsup> <mml:mrow> <mml:mn>54</mml:mn> </mml:mrow> <mml:mrow> <mml:mo>−</mml:mo> <mml:mn>23</mml:mn> </mml:mrow> <mml:mrow> <mml:mo>+</mml:mo> <mml:mn>31</mml:mn> </mml:mrow> </mml:msubsup> </mml:math> cm −3 and <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" overflow="scroll"> <mml:mi>p</mml:mi> <mml:mo>=</mml:mo> <mml:msubsup> <mml:mrow> <mml:mn>1.2</mml:mn> </mml:mrow> <mml:mrow> <mml:mo>−</mml:mo> <mml:mn>0.4</mml:mn> </mml:mrow> <mml:mrow> <mml:mo>+</mml:mo> <mml:mn>0.4</mml:mn> </mml:mrow> </mml:msubsup> </mml:math> . This power-law form may be explained by a combination of metallicity and morphological evolution of galaxies, which become, on average, more metal poor and more compact with increasing redshift.
Authors
- Matilde Mingozzi (ORCID: https://orcid.org/0000-0003-2589-762X)
- Pratika Dayal (ORCID: https://orcid.org/0000-0001-8460-1564)
- Seiji Fujimoto (ORCID: https://orcid.org/0000-0001-7201-5066)
- Colin Norman (ORCID: https://orcid.org/0000-0002-5222-5717)
- Massimo Ricotti (ORCID: https://orcid.org/0000-0003-4223-7324)
- Lukas J. Furtak (ORCID: https://orcid.org/0000-0001-6278-032X)
- Intae Jung (ORCID: https://orcid.org/0000-0003-1187-4240)
- Rogier A. Windhorst (ORCID: https://orcid.org/0000-0001-8156-6281)
- Vasily Kokorev (ORCID: https://orcid.org/0000-0002-5588-9156)
- Abdurrouf (ORCID: https://orcid.org/0000-0002-5258-8761)
- Rebecca L. Larson (ORCID: https://orcid.org/0000-0003-2366-8858)
- Christopher J. Conselice (ORCID: https://orcid.org/0000-0003-1949-7638)
- Brian Welch (ORCID: https://orcid.org/0000-0003-1815-0114)
- Angela Adamo (ORCID: https://orcid.org/0000-0002-8192-8091)
- Rachana Bhatawdekar (ORCID: https://orcid.org/0000-0003-0883-2226)
- Larry Bradley (ORCID: https://orcid.org/0000-0002-7908-9284)
- Dan Coe (ORCID: https://orcid.org/0000-0001-7410-7669)
- Arjan Bik (ORCID: https://orcid.org/0000-0001-8068-0891)
- Alejandro Crespo Gómez (ORCID: https://orcid.org/0000-0003-2119-277X)
- Tiger Yu-Yang Hsiao (ORCID: https://orcid.org/0000-0003-4512-8705)
- Javier Álvarez-Márquez (ORCID: https://orcid.org/0000-0002-7093-1877)
- Meghana Killi (ORCID: https://orcid.org/0000-0001-5289-3291)
- Xinfeng Xu (ORCID: https://orcid.org/0000-0002-9217-7051)
- E. Vanzella (ORCID: https://orcid.org/0000-0002-5057-135X)
- Jane R. Rigby (ORCID: https://orcid.org/0000-0002-7627-6551)
- Adi Zitrin (ORCID: https://orcid.org/0000-0002-0350-4488)
- J. M. Diego (ORCID: https://orcid.org/0000-0001-9065-3926)
- Tom Resseguier (ORCID: https://orcid.org/0009-0007-0522-7326)
- Taylor A. Hutchison
Publication Details
- Journal
- The Astrophysical Journal
- Published
- 2024-09-01
- DOI
- https://doi.org/10.3847/1538-4357/ad6001
- Citations
- 28
- Primary Topic
- Stellar, planetary, and galactic studies
- Type
- article
- Field-Weighted Citation Impact
- 9.28
Funders
- Space Telescope Science Institute
- Science and Technology Facilities Council