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Early Universe

All articles tagged with #early universe

Blazar OP 313 Identified as Most Distant Black Hole Beacon from Cosmic Dawn
astronomy2 days ago

Blazar OP 313 Identified as Most Distant Black Hole Beacon from Cosmic Dawn

Astronomers have identified Blazar OP 313 as the most distant and earliest blazar ever detected, providing a rare glimpse into the universe's high-activity phase. This object features a supermassive black hole emitting plasma jets directly toward Earth, with light that has traveled for 8 billion years. The discovery offers critical insights into the 'cosmic noon' era, a period of intense galaxy formation that occurred roughly 5 billion years after the Big Bang.

via Space|
#astronomy#blazar-op-313#cosmic-noon
Little Red Dots Hint at Dense, Metal-Poor Hosts in the Early Universe
space21 days ago

Little Red Dots Hint at Dense, Metal-Poor Hosts in the Early Universe

A new JWST analysis of 217 Little Red Dots (LRDs) in the early universe finds faint light from surrounding host galaxies, which are unusually compact (~1,400 light-years across) and metal-poor. The results suggest LRDs may be connected to bursts of star formation in their hosts (not just a central engine), offering a host-galaxy perspective on their origin and evolution. The study, led by Jorge Zavala (UMass Amherst), calls for spectroscopy and searches for local analogs, and was published in Nature Astronomy.

via space.com|
#compact-galaxies#early-universe#james-webb-space-telescope
Heavy seeds ignite rapid growth, linking JWST's little red dots to overmassive black holes
astronomy22 days ago

Heavy seeds ignite rapid growth, linking JWST's little red dots to overmassive black holes

Cosmological radiation‑hydrodynamic simulations show that ~10^6 solar‑mass heavy seeds can form in overdense protocluster regions under intense FUV radiation, quickly growing via brief super‑Eddington accretion to ~3×10^7 M⊙ by z ≈ 8. This unifies the high‑redshift little red dots observed by JWST with the overmassive black holes, as dense circum‑BH disks produce Balmer features and Hα emission without a traditional broad‑line region, while light‑seed remnants fail to grow similarly. The study also predicts X‑ray obscuration during early growth and potential LISA detections from BH mergers. Results are robust to changes in LW flux and higher resolution tests, offering a cohesive pathway from heavy‑seed formation to overmassive high‑z quasars.

via Nature|
#astronomy#direct-collapse#early-universe
Hunting the Universe’s First Stars with Gravitational Lenses
science25 days ago

Hunting the Universe’s First Stars with Gravitational Lenses

Population III stars formed from pristine gas roughly 100–250 million years after the Big Bang and, if massive, burned bright for only a few million years before dying and seeding heavier elements. No individual Pop III star has been definitively identified, largely because their light is faint and rare to spot, but gravitational lensing by galaxy clusters—along with JWST’s infrared power—offers a path to detect them. Earendel, a highly magnified star behind a foreground cluster, demonstrates the lensing method, though it is not a Pop III star. Detecting a true first star would require precise lens models and spectroscopy proving a pristine, metal-free atmosphere, plus accounting for microlensing variability. A confirmed Pop III detection would illuminate the early mass distribution of the first stars and the timeline of metal enrichment, though such a star may still remain elusive across the cosmos.

via Space Daily|
#early-universe#first-stars#gravitational-lensing
Ancient proto-supercluster COSMOS-z3.1-A: a 5,000 Milky Way–mass giant from the early universe
space29 days ago

Ancient proto-supercluster COSMOS-z3.1-A: a 5,000 Milky Way–mass giant from the early universe

Astronomers using deep imaging and spectroscopy identified COSMOS-z3.1-A as the earliest and most distant protocluster, seen when the Universe was about 2.1 billion years old and containing roughly 5,000 times the Milky Way’s mass. The object is a proto-supercluster that will merge into a giant cluster, with 3D mapping showing dense, clumpy subregions at the intersections of the cosmic web, illustrating bottom-up structure formation. The study, part of the ODIN survey, also highlights COSMOS-z3.1-C as another dense protocluster and anticipates evolving into masses surpassing the Coma Cluster; future surveys like the Vera Rubin Observatory’s LSST will help find more such ancient giants.

via BBC Sky at Night Magazine|
#cosmic-web#dark-matter#early-universe
Webb’s Red Dots Hint at a Hidden Black-Hole Star in the Early Universe
space1 month ago

Webb’s Red Dots Hint at a Hidden Black-Hole Star in the Early Universe

New analyses of faint red dots in JWST deep-field images suggest they may be black holes cloaked in a dense, star-like gas cocoon about the size of the solar system—the so-called “black hole star,” with a best-fit mass around 100,000 solar masses. If borne out, this challenges existing ideas about how the universe’s first massive black holes and stars form. Spectral clues like a deep Balmer break and numerous lines support the model, but no direct image exists and alternative explanations (dust geometry, dense star clusters) can’t yet be ruled out. Additional Webb observations are planned to test this emerging picture.

via Space Daily|
#astronomy#black-hole#early-universe
Ancient Oxygen in a 300‑Million‑Year‑Old Galaxy Reveals Early Stellar Enrichment
space1 month ago

Ancient Oxygen in a 300‑Million‑Year‑Old Galaxy Reveals Early Stellar Enrichment

ALMA detected the ionised oxygen [O III] 88 μm line in JADES-GS-z14-0, a galaxy seen when the universe was under 300 million years old (z ≈ 14.18), confirming rapid heavy‑element production by early generations of massive stars. The inferred abundances are about 5–20% of solar (around 17% in some models), indicating fast chemical enrichment, while not pinning down specific stellar histories or supernovae.

via spacedaily.com|
#alma#early-universe#jwst
The Fossil Light That Unlocked the Universe's Dawn
science1 month ago

The Fossil Light That Unlocked the Universe's Dawn

An accessible guide to the cosmic microwave background: the fossil light from 380,000 years after the Big Bang that made the universe transparent, now observed as a 2.7 K microwave map by COBE, WMAP, and Planck; its tiny fluctuations seed galaxies, constrain curvature and matter content, and even highlight the current tension in the measured Hubble constant, reminding us that the cosmos still has mysteries to unveil.

via Daily Kos|
#cosmic-microwave-background#early-universe#hubble-tension
Webb dots reveal early supermassive black holes in tiny galaxies
science1 month ago

Webb dots reveal early supermassive black holes in tiny galaxies

A Nature Astronomy study using JWST data from the COSMOS-Web region suggests the mysterious 'little red dots' are the earliest supermassive black holes, residing in very compact host galaxies that contain about 1 billion stars. The host galaxies are ~4% of the Milky Way’s size and contribute only ~10% of the dots’ light, while the central black holes (roughly 10^7–10^9 solar masses) dominate the emission. This implies black holes may grow most of their mass before their galaxies form most of their stars, shedding light on how black holes and galaxies co-evolve; the team analyzed 217 JWST images across a region about three times the Moon’s size to measure host properties and applied PSF subtraction to isolate the faint hosts.

via The Conversation|
#astronomy#black-holes#early-universe
Hidden Low-Mass Stars Make Early Massive Galaxies Much Heavier Than Thought
science1 month ago

Hidden Low-Mass Stars Make Early Massive Galaxies Much Heavier Than Thought

Webb Space Telescope observations (with VLT data) published in Nature Astronomy reveal a hidden population of small, faint stars in nine of the universe’s most massive early galaxies, implying those systems are far more massive than previously estimated. By analyzing subtle spectral signatures of low-mass stars, researchers found many more dwarfs than bright stars alone would suggest, with one galaxy formed within roughly 1.5 billion years after the Big Bang potentially four times heavier than thought. This challenges existing models of early galaxy growth and could have implications for planet formation around low-mass stars in the ancient universe.

via Gizmodo|
#astronomy#early-universe#galaxies
space1 month ago

One-Hour Light Bender Hints at Primordial Black Hole in Milky Way Halo

A star in the Large Magellanic Cloud briefly brightened for about an hour in 2019 due to gravitational microlensing by an unseen object nicknamed Phoebe. Its mass is estimated at roughly three lunar masses, too light to be a planet or stellar black hole. Analyses favor Phoebe being a dark-matter object in the Milky Way halo, with a primordial black hole as a leading exotic possibility; if confirmed, it would be among the oldest objects in the universe. Alternatives include a free-floating planet in the Milky Way or in the LMC. The event highlights microlensing as a tool to probe dark matter and compact objects.

via SciTechDaily|
#dark-matter#early-universe#gravitational-microlensing