Tag

Galaxies

All articles tagged with #galaxies

science19 days ago•122 min saved

Black Holes as Galactic Sculptors: Triggering Star Formation

Astronomers mapped nine nearby galaxies with active galactic nuclei to trace how energy from feeding supermassive black holes drives shocks in the surrounding gas, revealing that AGN outflows can spark rings of star formation 2,600 to 20,000 light-years from galactic centers. This study outlines a complex accretion–outflow feedback cycle that shapes galaxy evolution and was based on VLT/MUSE data; findings published in The Astrophysical Journal.

via Space|

#agn-feedback #black-holes #galaxies

science1 month ago•56 min saved

Counting the Cosmos: About 200 sextillion stars in the universe

Scientists estimate there are roughly 200 sextillion (2×10^23) stars in the universe by first counting the roughly 2 trillion galaxies, then multiplying by a typical galaxy’s star count (about 100 billion). Using the Milky Way as a model, they extrapolate to the entire cosmos, noting the Sun is just one of these stars and that many stars are red dwarfs. The article emphasizes how astronomers combine galaxy counts with stellar statistics to reach this staggering total.

via Yahoo|

#astronomy #galaxies #milky-way

science1 month ago•2 min saved

FAST Telescope Uncovers Why Star Formation Slows Despite Abundant Hydrogen

Using the FAST radio telescope and DESI, researchers analyzed ~2.5 million galaxies over 4.5 billion years to track neutral hydrogen. They found that 4.5 billion years ago the cosmic star-formation rate was about 2.5 times higher than today, while neutral hydrogen density was only ~1.4 times higher, indicating gas reserves did not simply deplete as star formation declined. The study suggests that as the overall gas density falls, the efficiency of converting neutral hydrogen to molecular gas (the fuel for stars) decreases, shrinking the molecular reservoir and slowing star formation. Findings published in Nature Astronomy.

via news.cgtn.com|

#astronomy #cosmology #fast-telescope

space1 month ago•14 min saved

Boötes Void: A colossal cosmic blank that could have hidden the universe

Boötes Void is a 330‑million‑light‑year‑wide cosmic void with far fewer galaxies than expected. First identified in 1981 via redshift surveys by Kirshner and colleagues, it sits inside the foam‑like large‑scale structure of the universe and underlines how our location shapes what we can observe: inside this void the Milky Way would likely have seen no other galaxies for decades, potentially until the 1960s were it at its center, with only about sixty galaxies found there compared with thousands in a typical patch.

via Space Daily|

#bootes-void #cosmic-voids #galaxies

space1 month ago•163 min saved

Cloud 9: Could the cosmos harbor the first truly starless galaxy?

Astronomers studying Cloud 9, a gas-rich object about 14 million light‑years from Earth near Messier 94, report that it shows virtually no starlight in the deepest optical imaging to date, making it the best candidate yet for a starless or “dark” galaxy. The team constrains any old, metal-poor stellar population to about 16,000 solar masses, while the region harbors roughly 1 million solar masses of hydrogen gas and a dark-matter halo of about 5 million solar masses. If confirmed, Cloud 9 would fit cosmological predictions that ultraviolet background radiation can suppress star formation in low-mass halos; however, deeper observations (e.g., with Hubble or JWST) are needed to rule out faint stars and prove it is truly starless.

via Space|

#astronomy #cosmology #dark-matter

space1 month ago•10 min saved

Giant 3.2-Gigapixel Eye to Map Billions of Galaxies Each Night

The Vera C. Rubin Observatory’s LSST camera—the largest digital camera ever built—uses a 3,200-megapixel (3.2 gigapixel) sensor array spread across 1.57 meters, with 189 ultra-clean CCDs cooled to -100°C to image the southern sky. It captures wide, fast exposures that sweep about seven times the width of a full moon, producing roughly 10 terabytes of data per night and aiming to catalog billions of galaxies and stars over its 10-year Legacy Survey, enabling unprecedented wide-field, time-domain astronomy and detailed structure in star-forming regions.

via ZME Science|

#astronomy #galaxies #lsst

science1 month ago•4 min saved

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

science1 month ago•2 min saved

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•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

space-and-spaceflight1 month ago•18 min saved

Astronomers Uncover a Black Hole Star in the Early Universe

Nature-published researchers report the discovery of MoM-BH*-1, a newly identified object that resembles a giant star but radiates energy like a black hole, wrapped in dense gas and outshining its host galaxy. Scientists label it a “black hole star,” a find that could illuminate how the first supermassive black holes formed and connect to the JWST-detected little red dots from the cosmic dawn; further JWST observations are planned to constrain its mass and atmospheric properties.

via Gizmodo|

#black-hole-star #early-universe #galaxies

space2 months ago•157 min saved

Andromeda's Star Formation Slows, Suspected Trigger: a Neighbor Named M32

Hubble observations show the Andromeda galaxy’s rate of turning gas into stars has dramatically slowed in the last ~40 million years, with the slowdown most pronounced on the side facing its tiny neighbor M32. While researchers acknowledge they can’t prove M32 caused the decline, it is the leading suspect, possibly due to a past collision. The study mapped Andromeda’s history across two-thirds of its disk, finding current star formation at about 0.2 solar masses per year (roughly one-fifth the Milky Way’s rate). The Nancy Grace Roman Space Telescope will help measure more of Andromeda’s stars to further test the M32-link in the coming years.

via Space|

#andromeda #galaxies #hubble-space-telescope

science2 months ago•3 min saved

Rubin Observatory Debuts Deep-Sky Mosaic Covering 500,000 Galaxies

The Rubin Observatory released its first science image from the LSST, a deep view of the COSMOS field featuring more than 500,000 galaxies (and about 50,000 foreground stars) captured with the 3.2-gigapixel LSST Camera. Part of Early Data Preview 2, the image previews the decade-long Legacy Survey of Space and Time and will be followed by repeated observations to study galaxy evolution and transient events like supernovae, building what scientists describe as the most comprehensive cinematic record of the universe.

via The Debrief|

#astronomy #cosmos-field #galaxies

science2 months ago•3 min saved

Rubin Observatory Captures 650,000 Galaxies in a Single COSMOS View

A new Rubin Observatory image of the COSMOS field captures more than 650,000 galaxies and 50,000 stars in a single deep view, thanks to its 3.2-gigapixel camera. Rubin will image this patch repeatedly over its decade-long LSST survey, enabling comparisons with Hubble and Webb and advancing studies of dark matter, dark energy, supernovae, and near-Earth asteroids.

via Gizmodo|

#astronomy #cosmos-field #galaxies

space2 months ago•5 min saved

Rubin Observatory Unveils 500,000+ Galaxies in a 3.2-Gigapixel COSMOS Deep Field

Rubin Observatory’s 3.2-gigapixel LSST camera captured a deep-field image of the COSMOS patch, stacking hundreds of exposures to reveal more than half a million galaxies as the telescope begins its decade-long mission to repeatedly image the sky and study galaxy evolution and transient phenomena.

via PetaPixel|

#astronomy #cosmos-field #galaxies

space2 months ago•10 min saved

Ten Space Revelations Redraw the Cosmos

Ten recent space discoveries—ranging from neon hints of Mars’ recent volcanism and the mature early galaxy Zhúlóng seen by JWST, to newborn planets around PDS 70 and a possible fifth world near L 98-59—demonstrate how JWST and Hubble are reshaping our understanding of planet formation, galaxy evolution, and cosmic history, while prompting new views on the Milky Way–Andromeda fate and the Sun’s distant future.

via Listverse|

#cosmology #exoplanets #galaxies