51ÁÔÆæÈë¿Ú

Abstract:

<jats:p>The non-linear dynamics of scalar fields coupled to matter and gravity can lead to remarkable density-dependent screening effects. In this short review, we present the main classes of screening mechanisms, and discuss their tests in laboratory and astrophysical systems. We particularly focused on reviewing numerical and technical aspects involved in modeling the non-linear dynamics of screening and on tests using laboratory experiments and astrophysical systems, such as stars, galaxies, and dark matter halos.</jats:p>

Abstract:

Cosmic dust—tiny, ancient particles adrift in space—holds the secret to how planets, and ultimately life, are born. Though nearly invisible, these microscopic grains are the architects of worlds. Formed in the death throes of stars, they float through the cosmos, merging, colliding, and evolving over billions of years until gravity and chemistry weave them into planets. This humble dust bridges the past and future of the universe: the remnants of dying stars become the seeds of new solar systems. Yet, cosmic dust also challenges our perception of significance. In every grain lies a history older than Earth itself, a reminder that our planet and bodies are sculpted from the same interstellar material. Understanding cosmic dust reshapes humanity’s sense of origin and belonging—it shows that creation is not a singular event but an unending cosmic cycle of destruction, transformation, and rebirth

Abstract:

We present JWST NIRCam nine-band near-infrared imaging of the luminous z = 10.6 galaxy GN-z11 from the JWST Advanced Deep Extragalactic Survey of the GOODS-N field. We find a spectral energy distribution (SED) entirely consistent with the expected form of a high-redshift galaxy: a clear blue continuum from 1.5 to 4 μm with a complete dropout in F115W. The core of GN-z11 is extremely compact in JWST imaging. We analyze the image with a two-component model, using a point source and a Sérsic profile that fits to a half-light radius of 200 pc and an index n = 0.9. We find a low-surface-brightness haze about 0.″4 to the northeast of the galaxy, which is most likely a foreground object but might be a more extended component of GN-z11. At a spectroscopic redshift of 10.60 (Bunker et al. 2023), the comparison of the NIRCam F410M and F444W images spans the Balmer jump. From population-synthesis modeling, here assuming no light from an active galactic nucleus, we reproduce the SED of GN-z11, finding a stellar mass of ∼109 M ⊙, a star formation rate of ∼20 M ⊙ yr−1, and a young stellar age of ∼20 Myr. Since massive galaxies at high redshift are likely to be highly clustered, we search for faint neighbors of GN-z11, finding nine galaxies out to ∼5 comoving Mpc transverse with photometric redshifts consistent with z = 10.6, and a tenth more tentative dropout only 3″ away. This is consistent with GN-z11 being hosted by a massive dark-matter halo (≈8 × 1010 M ⊙), though lower halo masses cannot be ruled out

Abstract:

In the local Universe, the ratio between the mass of a central black hole and the stellar mass of its host galaxy is $\sim 0.1 \%$. Recently, JWST discovered numerous galaxies at $z>4$ that seem to deviate from the local relation, with black holes overmassive by $10-100$ times. Similar galaxies were also discovered at cosmic noon. The intrinsic scatter in the relation describes how much the evolutionary histories of the single galaxies deviate from the mean evolutionary pattern of their parent dataset. This Research Note examines whether a cosmic evolution of the intrinsic scatter can be detected by assessing its value for datasets in various redshift ranges. Using data from the local Universe ($z < 0.055$), low ($ 0.4 \leq z \leq 0.9$), intermediate ($ 0.9 \leq z \leq 4$), and high ($z > 4$) redshift, we conclude that there is no statistically significant redshift evolution of the intrinsic scatter.Comment: Accepted on Research Notes of the AAS. This is a concise note (3 pages, 1 figure) regarding the direct application of the model described in arXiv:2308.12331 to various datasets of overmassive black holes in various redshift range