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Extreme emission line galaxies (EELGs), where nebular emissions contribute 30%–40% of the flux in certain photometric bands, are ubiquitous in the early Universe ( z > 6). We utilize deep NIRCam imaging from the JWST Advanced Deep Extragalactic Survey ( JADES ) to investigate the properties of companion galaxies (projected distance <40 kpc, ∣ dv ∣...
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... results presented in this Letter use a projected distance d pro < 40 kpc and velocity offset |dv| < 10000 km s −1 (∼1.5 × σ NMAD companions). Figure 2 shows examples of companions identified around a subset of EELGs (See Table 2 , where Δz = 0.1 * (1 + z peak ). Our main conclusions do not change significantly if we restrict the analysis to companions with I > 0.75. ...Context 2
... properly accounting for mergers would be important while estimating physical properties of gas and stars, in particular their kinematics and morphology in the early Universe. Table 2 presents the list of EELGs located within the JADES DR1 footprint, along with properties of companion galaxies identified around each EELG, as determined by the criteria outlined in Section 3.3. Notes. ...Similar publications
Giant low surface brightness galaxies (GLSBGs) are fundamentally distinct from normal galaxies and other types of LSBGs in terms of star formation and evolution. In this work, we collected 27 local GLSBGs from the literature. They have high stellar masses ( M * > 10 ¹⁰ M ⊙ ) and low far-ultraviolet-based star formation rates (SFRs). With specific s...
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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. ...
We study a sample of 14 spectroscopically confirmed Ly α emitters (LAEs) in the late era of reionization (at redshift z ≈ 6) based on the JWST/NIRCam imaging data set. These LAEs with high Ly α luminosity of L (Ly α ) ∼10 42.4 –10 43.4 erg s ⁻¹ have been covered by the (ongoing) COSMOS-Web survey over 0.28 deg ² 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 Ly α equivalent width and the offset between Ly α and UV emission (Δ d Ly α ), with a median Δ d Ly α ∼ 1 kpc. This could be explained by the Ly α 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.
Unraveling the problem of impossibly early galaxies, we propose a model in which a galaxy’s luminosity consistently depends on two types of stars that differ only in mass and thus have different types of their evolution. At the initial stage, up to 1 Gyr from the Big Bang, the luminosity is mostly determined by stars with masses greater than 8М 🖸 , which have a short life cycle and inevitably end their evolution with supernovae outbursts. But then, in the later Universe, the galaxy luminosity function (GLF) begins to depend on the much more numerous stars with masses less than 8М 🖸 , which continue on the main sequence. Thus, we find that the initial increased luminosity (“supernovae fireworks”) occurs at much lower galaxy masses. To evaluate the hypothesis, we propose an observational test, where we measure the luminosity irregularities (> 3σ) of those six too bright early galaxies, to be taken over a period of 8–12 months.
