MOSEL Survey: JWST Reveals Major Mergers/strong Interactions Drive the Extreme Emission Lines in the Early Universe

Gupta, Anshu; Jaiswar, Ravi; Rodriguez-Gomez, Vicente; Forrest, Ben; Tran, Kim-Vy; Nanayakkara, Themiya; Harshan, Anishya; da Cunha, Elisabete; Kacprzak, Glenn G.; Hirschmann, Michaela

doi:10.3847/2041-8213/ad0788

Cited by 3 publications

(1 citation statement)

References 64 publications

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“…Hence, the merging/interacting systems probably favor that Lyα origin may occur in the circumgalactic medium (CGM) regions. In merger activities, strong interactions between the CGM of each component can induce gas cooling (e.g., Sparre et al 2022;Gupta et al 2023) and then produce additional Lyα emission.…”

Section: Potential Mergers In the Lae Samplementioning

confidence: 99%

Unveiling Luminous Lyα Emitters at z ≈ 6 through JWST/NIRCam Imaging in the COSMOS Field

Ning,

Cai,

Lin

et al. 2024

ApJL

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We study a sample of 14 spectroscopically confirmed Lyα emitters (LAEs) in the late era of reionization (at redshift z ≈ 6) based on the JWST/NIRCam imaging data set. These LAEs with high Lyα luminosity of L(Lyα) ∼1042.4–1043.4 erg s−1 have been covered by the (ongoing) COSMOS-Web survey over 0.28 deg2 in four NIRCam bands (F115W, F150W, F277W, and F444W). With JWST/NIRCam imaging, we determine the UV continua with M UV ranging from −20.5 to −18.5 mag. The UV slopes have a median value of β ≈ −2.35, and the steepest slopes can reach β < −3. Under the excellent spatial resolution of JWST, we identify three objects in the sample as potential merging/interacting systems. The 14 LAEs (and their components) are compact in morphology, residing substantially below the mass–size relation of high-z galaxies. We further investigate their physical properties, including the stellar mass (M *) and star formation rates (SFRs). Most of the LAEs lie on the SFR–M * main-sequence relation, while two of them, featured as “little red dots,” likely host active galactic nuclei (AGNs), implying a ∼10% AGN fraction. Moreover, we reveal that a new correlation may exist between Lyα equivalent width and the offset between Lyα and UV emission (Δd Lyα ), with a median Δd Lyα ∼ 1 kpc. This could be explained by the Lyα radiative transfer process in both the interstellar medium and circumgalactic medium. The results usher in a new era of detailed analysis on high-z LAEs with the JWST capability.

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Section: Potential Mergers In the Lae Samplementioning

confidence: 99%

Unveiling Luminous Lyα Emitters at z ≈ 6 through JWST/NIRCam Imaging in the COSMOS Field

Ning,

Cai,

Lin

et al. 2024

ApJL

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JADES: measuring reionization properties using Lyman-alpha emission

Jones,

Bunker,

Saxena

et al. 2024

Monthly Notices of the Royal Astronomical Society

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Lyα is the transition to the ground state from the first excited state of hydrogen (the most common element). Resonant scattering of this line by neutral hydrogen greatly impedes its emergence from galaxies, so the fraction of galaxies emitting Lyα is a tracer of the neutral fraction of the intergalactic medium (IGM), and thus the history of reionisation. In previous works, we used early JWST/NIRSpec data from the JWST Advanced Deep Extragalactic Survey (JADES) to classify and characterise Lyα emitting galaxies (LAEs). This survey is approaching completion, and the current sample is nearly an order of magnitude larger. From a sample of 795 galaxies in JADES at 4.0 < z < 14.3, we find evidence for Lyα emission in 150 sources. We reproduce the previously found correlation between Lyα escape fraction ($f\rm _{esc}^{Ly\alpha }$) - Lyα rest-frame equivalent width (REWLyα) and the negative correlation between Lyα velocity offset - $f\rm _{esc}^{Ly\alpha }$. Both $f\rm _{esc}^{Ly\alpha }$ and REWLyα decrease with redshift (z ≳ 5.5), indicating the progression of reionisation on a population scale. Our data are used to demonstrate an increasing IGM transmission of Lyα from z ∼ 14 − 6. We measure the completeness-corrected fraction of LAEs ($X\rm _{Ly\alpha }$) from z = 4 − 9.5. An application of these $X\rm _{Ly\alpha }$ values to the results of previously utilised semi-analytical models suggests a high neutral fraction at z = 7 (XHI ∼ 0.8 − 0.9). Using an updated fit to the intrinsic distribution of REWLyα results in a lower value in agreement with current works (${X_{\rm HI}}= 0.64_{-0.21}^{+0.13}$). This sample of LAEs will be paramount for unbiased population studies of galaxies in the EoR.

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MOSEL Survey: Spatially Offset Lyman-continuum Emission in a New Emitter at z = 3.088 Can Explain the Low Number Density of Observed LyC Leakers

Gupta,

Trott,

Jaiswar

et al. 2024

ApJ

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We present the discovery of a unique Lyman-continuum (LyC) emitter at z = 3.088. The LyC emission was detected using the Hubble Space Telescope WFC3/UVIS F336W filter, covering a rest-frame wavelength range of 760–900 Å. The peak signal-to-noise ratio of LyC emission is 3.9 in an r = 0.″24 aperture and is spatially offset by 0.″29 ± 0.″04 (∼2.2 ± 0.3 kpc) from the peak of rest-UV emission (F606W). By combining imaging and spectroscopic data from the James Webb Space Telescope (JWST) JADES, FRESCO, and JEMS surveys, along with VLT/MUSE data from the MXDF survey, we estimate that the probability of random alignment with an interloper galaxy causing the LyC emission is less than 6 × 10−5. The interstellar medium (ISM) conditions in the galaxy are similar to those in other LyC emitters at high redshift ( 12 + log ( O / H ) = 7.79 − 0.05 + 0.06 , log U = − 3.27 − 0.12 + 0.14 , O32 = 0.63 ± 0.03), although the single-peaked Lyα profile and lack of rest-UV emission lines suggest an optically thick ISM. Our observations indicate that LyC photons are leaking through a narrow cone of optically thin neutral ISM, most likely created by a past merger (as evidenced by medium-band F210M and F182M images). Using the constraints on escape fraction from individual leakers and a simple model, we estimate that the opening half-angle of ionization cones can be as small as 16° (2% ionized fraction) to reproduce some of the theoretical constraints on the average escape fraction for galaxies. The narrow opening angle required can explain the low number density of confirmed LyC leakers.

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MOSEL Survey: JWST Reveals Major Mergers/strong Interactions Drive the Extreme Emission Lines in the Early Universe

Cited by 3 publications

References 64 publications

Unveiling Luminous Lyα Emitters at z ≈ 6 through JWST/NIRCam Imaging in the COSMOS Field

Unveiling Luminous Lyα Emitters at z ≈ 6 through JWST/NIRCam Imaging in the COSMOS Field

JADES: measuring reionization properties using Lyman-alpha emission

MOSEL Survey: Spatially Offset Lyman-continuum Emission in a New Emitter at z = 3.088 Can Explain the Low Number Density of Observed LyC Leakers

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