Tag

Globular Clusters

All articles tagged with #globular clusters

astronomy7 days ago•4 min saved

Ancient Milky Way merger revealed by globular-cluster fossils

A Nature Astronomy study uses precise ages and metallicities of Milky Way globular clusters to reconstruct the Galaxy’s early growth, revealing three distinct age–metallicity tracks and an ancient major merger (progenitor Low-energy–Kraken–Heracles) about 12 billion years ago with roughly 500 million solar masses, depositing most material in the inner Milky Way. This refines the Milky Way’s formative timeline and complements JWST views of distant galaxies by tying together fossil stars and early-universe observations.

via The Conversation|

#astronomy #early-universe #gaia-sausage-enceladus

space12 days ago•206 min saved

Cosmic breadcrumb: first globular-cluster stellar stream spotted beyond the Milky Way

Astronomers discovered the first globular-cluster stellar stream outside the Milky Way, in a galaxy about 115 million light-years away, by analyzing archival data from the Hubble Space Telescope. The faint stellar trail reveals the host galaxy's gravitational field and total mass, offering a new way to map dark matter and understand how galaxies form and evolve across the universe.

via CNN|

#dark-matter #galaxies #globular-clusters

science1 month ago•51 min saved

JWST's Little Red Dots May Be the Birthplace of Globular Clusters

Astronomers propose that the James Webb Space Telescope’s early “Little Red Dots”—compact sources seen about 600 million years after the Big Bang and then fading—could be the births of globular clusters, forming around short‑lived supermassive stars. The dots’ chemical signatures, distribution, and timing resemble properties of modern globular clusters, suggesting these objects may persist and evolve into familiar clusters like 47 Tucanae. While not a definitive proof, the idea links JWST’s surprising early-population observations to the origins of ancient star clusters observed today.

via Yahoo|

#early-universe #globular-clusters #jwst

science1 month ago•106 min saved

JWST’s Little Red Dots Could Be Birthplaces of Ancient Globular Clusters

New research suggests the James Webb Space Telescope’s bright, compact “Little Red Dots” seen around 600 million years after the Big Bang may be the early building blocks of globular clusters, potentially forming around short-lived supermassive stars. If these dots persist and evolve, they could become the dense stellar systems observed today, linking early-universe observations to mature globular clusters and shedding light on star formation in the universe’s youth.

via Space|

#early-universe #globular-clusters #james-webb-space-telescope

science3 months ago•2 min saved

Dense Dark Matter Clumps Might Unify Three Cosmic Puzzles

A UC Riverside study proposes that dense clumps of self-interacting dark matter (SIDM) can undergo gravothermal collapse to form compact cores that explain three different observations—an ultra-dense object in the gravitational lens JVAS B1938+666, perturbations in the GD-1 stellar stream, and the unusually young, metal-rich Fornax 6 globular cluster in the Fornax dwarf galaxy—linking distant lensing, our Galaxy, and a satellite galaxy under one mechanism, unlike collisionless CDM. The work, published in Physical Review Letters, is supported by the John Templeton Foundation and the DoE.

via Universe Today|

#dark-matter-halos #globular-clusters #gravitational-lensing

space3 months ago•73 min saved

Massive black holes may form in crowded star clusters through successive mergers

A new study of 153 black hole mergers from GWTC4 finds two distinct populations: lighter black holes born from massive-star collapses and heavier ones likely created by hierarchical mergers in dense star clusters, supporting a predicted mass gap around 45 solar masses and suggesting the largest black holes grow primarily via cluster mergers rather than direct stellar collapse.

via Space|

#black-holes #globular-clusters #gravitational-waves

space5 months ago•75 min saved

JWST Dots May Be Young Globular Clusters, Not Baby Black Holes

A Space.com analysis of James Webb Space Telescope data suggests the mysterious “Little Red Dots” from the early universe could be newborn globular clusters rather than proto-black holes. A new arXiv study proposes these LRDs host very young stellar populations, potentially powered by an extremely massive, short‑lived star, which could explain their distinctive V‑shaped spectrum. The observed redshift range aligns with metal‑poor globular clusters, and the team estimates a global formation density around 0.3 per cubic megaparsec, similar to the number of globular clusters today. If confirmed, this would provide a direct window into early globular cluster formation, though future spectroscopy tracking chemical signatures (like helium and nitrogen enhancements, and specific element anti-correlations) will be crucial to test the hypothesis.

via Space|

#early-universe #galaxy-formation #globular-clusters

space5 months ago•185 min saved

Hubble Spots a Galaxy 99.9% Dark Matter

Astronomers using data from the Hubble Space Telescope, Euclid and the Subaru Telescope identified Candidate Dark Galaxy-2 (CDG-2), a distant galaxy that appears to be about 99.9% dark matter and extremely star-poor. The galaxy’s mass is inferred from a halo of four globular clusters, suggesting a rare, almost-dark galaxy that could provide a cleaner probe of dark matter—though further observations, including with the James Webb Space Telescope, are needed to confirm its dark matter content.

via CNN|

#dark-galaxy #dark-matter #galaxy

science5 months ago•185 min saved

Hubble spots galaxy made almost entirely of dark matter

Astronomers using the Hubble Space Telescope, Euclid, and the Subaru Telescope have identified Candidate Dark Galaxy-2 (CDG-2) in the Perseus Cluster, a galaxy so faint it’s dominated by dark matter—at least 99.9%—with four globular clusters indicating a massive dark halo and little to no starlight. The finding, based on globular clusters around a largely starless galaxy, suggests such dark galaxies may be common and could provide clean tests of dark matter physics; further observations with the James Webb Space Telescope could help confirm its dark matter content.

via CNN|

#dark-galaxies #dark-matter #galaxy

science5 months ago•3 min saved

Canadian Team Unveils Ghost Galaxy Almost Entirely Dark

A Canadian-led team using NASA’s Hubble, ESA’s Euclid and the Subaru Telescope has identified CDG-2, a candidate dark galaxy about 250 million light-years away that appears nearly invisible and is thought to be mostly dark matter, detected via a faint glow around four globular clusters. The galaxy is estimated to shine like only about 5 million stars, far fewer than the Milky Way, and researchers believe past interactions stripped away most of its stars—highlighting how indirect observations can reveal elusive cosmic structures and advance dark matter studies.

via CTV News|

#astronomy #cdg-2 #dark-matter

science6 months ago•39 min saved

Gaia Uncovers a Black-Hole Swarm in Palomar 5, Destined to Dissolve

Gaia data reveal Palomar 5, a Milky Way globular cluster with an extensive tidal stream, may host over 100 stellar-mass black holes, making up about 20% of the cluster’s mass. Detailed simulations that include these black holes show they can eject stars into the cluster’s tidal tails, hastening its dissolution into a stream of black holes that will orbit the galactic center in around a billion years. The finding suggests such black-hole-rich clusters may be common and could be important for understanding black-hole mergers.

via Yahoo|

#black-holes #gaia #globular-clusters

space6 months ago•5 min saved

A Galaxy Nearly All Dark Matter, Revealed by Four Star Clusters

Astronomers have confirmed CDG-2, a faint galaxy in the Perseus cluster detected only through four globular clusters that provide about 16% of its light; by combining data from Hubble, Euclid, and Subaru, they estimate the galaxy’s total luminosity at roughly 6 million suns and a mass composed of 99.94%–99.98% dark matter, making it one of the most dark-matter–dominated galaxies and a valuable natural laboratory for studying dark matter and galaxy formation.

via WIRED|

#astronomy #cdg-2 #dark-matter

astronomy6 months ago•53 min saved

Hubble Reveals CDG-2, a Galaxy 99% Dark Matter

Astronomers using Hubble, with Euclid and Subaru, identified CDG-2 in the Perseus cluster as an extremely dark-matter–dominated galaxy—about 245 million to 300 million light-years away—where 99% of its mass is dark matter. The galaxy was detected indirectly by tracing four tightly packed globular clusters, which reveal a faint glow around them. Its normal matter is estimated at roughly 6 million sun-like stars, with about 16% accounted for by the globular clusters, suggesting past star formation that has since been stripped away by gravitational interactions. The discovery, highlighting a “dark galaxy” category, was reported in The Astrophysical Journal Letters.

via Space|

#astronomy #cdg-2 #dark-matter

space-and-spaceflight6 months ago•16 min saved

Galaxy Cloaked in Darkness Hints at 99% Dark Matter

Astronomers using the Hubble Space Telescope identified CDG-2, a very dim galaxy in the Perseus cluster that appears to be 99% dark matter, with most of its normal matter stripped away by the crowded environment; the galaxy is inferred from a surrounding globular cluster population, marking it as one of the most dark-matter–dominated galaxies and a test bed for theories of dark matter and star formation.

via Gizmodo|

#cdg-2 #dark-galaxies #dark-matter

science6 months ago•4 min saved

Hubble Reveals One of the Universe’s Darkest Galaxies Hidden in Globular Clusters

NASA’s Hubble identified CDG-2, a remarkably dark matter–dominated, low-surface-brightness galaxy in the Perseus cluster, by spotting a small group of globular clusters and a faint surrounding glow. Four tightly bound clusters signal an underlying galaxy whose luminosity is about 6 million Sun-like stars, with about 99% of its mass in dark matter and most normal matter stripped away by gravitational interactions. Confirmed through combined data from Hubble, the Euclid mission, and the Subaru Telescope, this is the first galaxy detected primarily via its globular clusters, illustrating how upcoming surveys and machine-learning methods will uncover more such faint systems.

via NASA Science (.gov)|

#dark-matter #globular-clusters #hubble-space-telescope