Schrodinger's Galaxy Candidate: Puzzlingly Luminous at $z\approx17$, or Dusty/Quenched at $z\approx5$? (2208.02794v1)

Abstract: $JWST$'s first glimpse of the $z>10$ Universe has yielded a surprising abundance of luminous galaxy candidates. Here we present the most extreme of these systems: CEERS-1749. Based on $0.6-5\mu$m photometry, this strikingly luminous ($\approx$26 mag) galaxy appears to lie at $z\approx17$. This would make it an $M_{\rm{UV}}\approx-22$, $M_{\rm{\star}}\approx5\times10^{9}M_{\rm{\odot}}$ system that formed a mere $\sim220$ Myrs after the Big Bang. The implied number density of this galaxy and its analogues challenges virtually every early galaxy evolution model that assumes $\Lambda$CDM cosmology. However, there is strong environmental evidence supporting a secondary redshift solution of $z\approx5$: all three of the galaxy's nearest neighbors at $<2.5$" have photometric redshifts of $z\approx5$. Further, we show that CEERS-1749 may lie in a $z\approx5$ protocluster that is $\gtrsim5\times$ overdense compared to the field. Intense line emission at $z\approx5$ from a quiescent galaxy harboring ionized gas, or from a dusty starburst, may provide satisfactory explanations for CEERS-1749's photometry. The emission lines at $z\approx5$ conspire to boost the $>2\mu$m photometry, producing an apparent blue slope as well as a strong break in the SED. Such a perfectly disguised contaminant is possible only in a narrow redshift window ($\Delta z\lesssim0.1$), implying that the permitted volume for such interlopers may not be a major concern for $z>10$ searches, particularly when medium-bands are deployed. If CEERS-1749 is confirmed to lie at $z\approx5$, it will be the highest-redshift quiescent galaxy, or one of the lowest mass dusty galaxies of the early Universe detected to-date. Both redshift solutions of this intriguing galaxy hold the potential to challenge existing models of early galaxy evolution, making spectroscopic follow-up of this source critical.

• The paper presents a dual interpretation of Schrodinger’s Galaxy Candidate as either a high-redshift luminous source (z∼17) or a dusty, quenched galaxy at z∼5.
• It employs detailed photometric analysis and SED modeling using deep-field JWST observations to discriminate between the competing scenarios.
• The findings challenge existing galaxy formation models and underscore the need for further surveys to clarify early universe galaxy evolution.

Analysis of "Two Remarkably Luminous Galaxy Candidates at $z\approx11-13$ Revealed by JWST"

The research paper entitled "Two Remarkably Luminous Galaxy Candidates at $z\approx11-13$ Revealed by JWST" presents a significant advancement in high-redshift galaxy observations using the James Webb Space Telescope (JWST). This paper investigates galaxy formation during the early universe, an epoch that previously lacked substantial observational data.

Discoveries and Photometric Analysis

The paper identifies two robust candidates for high-redshift galaxies, referred to as GLASS-z11 and GLASS-z13, using the JWST's Near-Infrared Camera (NIRCam). These galaxies are characterized by strong photometric breaks, likely corresponding to complete absorption of light blueward of the Lyman-alpha line at redshifts $z\approx11$ and $z\approx13$. The photometric observations were carried out across several deep fields within various JWST Early Release Science programs, leveraging a cumulative area of approximately 60.5 arcmin$^2$.

The photometric redshift estimates for these candidates are bolstered by spectral energy distribution (SED) modeling that excludes lower-redshift solutions, such as those from dusty, quiescent galaxies. The analysis confirms high significance detections of both candidates in redder JWST filters, while findings show no significant flux in the filters blueward of the Lyman-alpha break, aligning with the expectations for galaxies at such high redshifts.

Implications for Early Universe Studies

The paper emphasizes the implications of these findings on our understanding of galaxy formation and evolution in the early universe. The existence of such luminous galaxies at $z>10$ suggests that significant galaxy formation activity occurred shortly after the Big Bang, challenging current models predicting the number density of such massive galaxies in this epoch. The inferred stellar masses for these galaxies, at around $10^9 M_{\odot}$, suggest rapid formation and accumulation of mass in the cosmic dawn period.

Theoretical Implications and Future Prospects

These findings prompt a re-evaluation of the UV luminosity function at high redshifts, specifically regarding the persistence of bright-end galaxies. The observed UV luminosity density is consistent with the existence of a substantial population of luminous galaxies beyond $z\approx 10$, potentially extending the trends seen at lower redshifts.

The discoveries made by the JWST in its initial observations underscore its transformative potential in extragalactic astronomy. The observations suggest minimal evolution in the bright end of the UV luminosity function and demand refinements in theoretical models accounting for rapid stellar mass assembly in the early universe. The high sensitivity of JWST can facilitate more comprehensive surveys, offering the prospect of validating these early results across larger volumes.

In conclusion, the detection of GLASS-z11 and GLASS-z13 demonstrates the formidable capabilities of JWST in probing the early universe. By expanding our cosmic perspective, it enables new inquiries into high-redshift galaxy properties and formation mechanisms, setting the stage for refined models and future explorations. As JWST continues its mission, it promises to shed further light on the early stages of galaxy development and cosmic structure formation.