PRESS-NEWS.org - Press Release Distribution
PRESS RELEASES DISTRIBUTION

Hubble uncovers concentration of small black holes

Hubble uncovers concentration of small black holes
2021-02-11
(Press-News.org) Globular clusters are extremely dense stellar systems, in which stars are packed closely together. They are also typically very old -- the globular cluster that is the focus of this study, NGC 6397, is almost as old as the Universe itself. It resides 7800 light-years away, making it one of the closest globular clusters to Earth. Because of its very dense nucleus, it is known as a core-collapsed cluster.

When Eduardo Vitral and Gary A. Mamon of the Institut d'Astrophysique de Paris set out to study the core of NGC 6397, they expected to find evidence for an "intermediate-mass" black hole (IMBH). These are smaller than the supermassive black holes that lie at the cores of large galaxies, but larger than stellar-mass black holes formed by the collapse of massive stars. IMBH are the long-sought "missing link" in black hole evolution and their mere existence is hotly debated, although a few candidates have been found (see [1], for example).

To look for the IMBH, Vitral and Mamon analysed the positions and velocities of the cluster's stars. They did this using previous estimates of the stars' proper motions [2] from Hubble images of the cluster spanning several years [3], in addition to proper motions provided by ESA's Gaia space observatory, which precisely measures the positions, distances and motions of stars. Knowing the distance to the cluster allowed the astronomers to translate the proper motions of these stars into velocities.

"Our analysis indicated that the orbits of the stars are close to random throughout the globular cluster, rather than systematically circular or very elongated," explained Mamon.

"We found very strong evidence for invisible mass in the dense central regions of the cluster, but we were surprised to find that this extra mass is not point-like but extended to a few percent of the size of the cluster," added Vitral.

This invisible component could only be made up of the remnants (white dwarfs, neutron stars, and black holes) of massive stars whose inner regions collapsed under their own gravity once their nuclear fuel was exhausted. The stars progressively sank to the cluster's centre after gravitational interactions with nearby less massive stars, leading to the small extent of the invisible mass concentration. Using the theory of stellar evolution, the scientists concluded that the bulk of the unseen concentration is made of stellar-mass black holes, rather than white dwarfs or neutron stars that are too faint to observe.

Two recent studies had also proposed that stellar remnants and in particular, stellar-mass black holes, could populate the inner regions of globular clusters.

"Our study is the first finding to provide both the mass and the extent of what appears to be a collection of mostly black holes in a core-collapsed globular cluster," said Vitral.

"Our analysis would not have been possible without having both the Hubble data to constrain the inner regions of the cluster and the Gaia data to constrain the orbital shapes of the outer stars, which in turn indirectly constrain the velocities of foreground and background stars in the inner regions," added Mamon, attesting to an exemplary international collaboration.

The astronomers also note that this discovery raises the question of whether mergers of these tightly packed black holes in core-collapsed globular clusters may be an important source of gravitational waves recently detected by the Laser Interferometer Gravitational-Wave Observatory (LIGO) experiment.

INFORMATION:

Notes [1] In 2020, new data from the NASA/ESA Hubble Space Telescope provided the strongest evidence to date for a mid-sized black hole. Read the full press release on this result here.

[2] Proper motion describes how fast objects move in the sky.

[3] The Hubble data for this study were provided by A. Bellini, who measured the proper motions for over 1.3 million stars in 22 globular clusters, including NGC 6397.

More information: The Hubble Space Telescope is a project of international cooperation between ESA and NASA.

The international team of astronomers in this study consists of E. Vitral and G. A. Mamon. The results have been published today in Astronomy & Astrophysics.


[Attachments] See images for this press release:
Hubble uncovers concentration of small black holes

ELSE PRESS RELEASES FROM THIS DATE:

Echocardiographic screening for rheumatic heart disease in Nepal

Echocardiographic screening for rheumatic heart disease in Nepal
2021-02-11
Rheumatic heart disease (RHD) develops as a long term complication of childhood streptococcal angina. Latent RHD can be detected with echocardiography years before it becomes symptomatic. RHD is curable when treated early with medication. RHD is responsible for over 300 000 deaths worldwide each year, accounting for just over two-thirds of all deaths from valvular heart diseases. RHD is disproportionally prevalent across sub-Saharan Africa, South Asia and the Pacific Islands and largely a phenomenon of marginalized communities in developing and emerging countries whereas ...

Recommendations for regional action to combat marine plastic pollution

2021-02-11
Millions of tonnes of plastic waste find their way into the ocean every year. A team of researchers from the Institute for Advanced Sustainability Studies (IASS) in Potsdam has investigated the role of regional ocean governance in the fight against marine plastic pollution, highlighting why regional marine governance should be further strengthened as negotiations for a new global agreement continue. In recent years, images of whales and sea turtles starving to death after ingesting plastic waste or becoming entangled in so-called ghost nets have led to a growing ...

To help keep cats from killing wildlife, add more meat and play to their day

To help keep cats from killing wildlife, add more meat and play to their day
2021-02-11
Domestic cats are a major threat to wild species, including birds and small mammals. But researchers reporting in the journal Current Biology on February 11 now have evidence that some simple strategies can help to reduce cats' environmental impact without restricting their freedom. Their studies show that domestic cats hunt less when owners feed them a diet including plenty of meat proteins. Equally, it helps to play with them each day in ways that allow cats to mimic hunting. "While keeping cats indoors is the only sure-fire way to prevent hunting, some owners ...

Play and meaty food reduce hunting by cats

Play and meaty food reduce hunting by cats
2021-02-11
Domestic cats hunt wildlife less if owners play with them daily and feed them a meat-rich food, new research shows. Hunting by cats is a conservation and welfare concern, but methods to reduce this are controversial and often rely on restricting cat behaviour in ways many owners find unacceptable. The new study - by the University of Exeter - found that introducing a premium commercial food where proteins came from meat reduced the number of prey animals cats brought home by 36%, and also that five to ten minutes of daily play with an owner resulted ...

Artificial intelligence generates new diversity of AAV capsids for broader gene therapy

2021-02-11
Cambridge, MA - February 11, 2020 - Dyno Therapeutics, a biotech company applying artificial intelligence (AI) to gene therapy, today announced a publication in Nature Biotechnology that demonstrates the use of artificial intelligence to generate an unprecedented diversity of adeno-associated virus (AAV) capsids towards identifying functional variants capable of evading the immune system, a factor that is critical to enabling all patients to benefit from gene therapies. The research was conducted in collaboration with Google Research, Harvard's Wyss Institute for Biologically Inspired Engineering and the Harvard Medical School laboratory of George M. Church, Ph.D., a Dyno scientific co-founder. The publication is entitled "Deep diversification ...

Compounds from apples may boost brain function

Compounds from apples may boost brain function
2021-02-11
Natural compounds found in apples and other fruits may help stimulate the production of new brain cells, which may have implications for learning and memory, according to a END ...

Machine-learning how to create better AAV gene delivery vehicles

Machine-learning how to create better AAV gene delivery vehicles
2021-02-11
(Boston) -- Adeno-associated viruses (AAVs) have become promising vehicles for delivering gene therapies to defective tissues in the human body because they are non-pathogenic and can transfer therapeutic DNA into target cells. However, while the first gene therapy products approved by the Federal Drug Administration (FDA) use AAV vectors and others are likely to follow, AAV vectors still have not reached their full potential to meet gene therapeutic challenges. First, currently used AAV capsids - the spherical protein structures enveloping the virus' single-stranded DNA genome which can be modified to encode therapeutic genes - are limited in their ability to specifically hone in on the tissue affected by a disease and their wider distribution throughout ...

Aggressive brain tumor mapped in genetic, molecular detail

Aggressive brain tumor mapped in genetic, molecular detail
2021-02-11
Glioblastoma is among the most aggressive and devastating of cancers. While rare compared with other cancers, it's the most common type of brain cancer. Even with intensive therapy, relatively few patients survive longer than two years after diagnosis, and fewer than 10% of patients survive beyond five years. Despite extensive studies focused on genomic features of glioblastoma, relatively little progress has been made in improving treatment for patients with this deadly disease. Now, a new study led by Washington University School of Medicine in St. Louis, Pacific Northwest National Laboratory, Case Western Reserve University and the National Cancer Institute (NCI) of the National Institutes of Health (NIH) has revealed a detailed map of the genes, ...

SARS-CoV-2 screening using CRISPR-based methods

2021-02-11
What The Study Did: This observational study assessed CRISPR-based methods for screening to detect SARS-CoV-2 among asymptomatic college students. Authors: Carolina Arias, Ph.D., of the University of California, Santa Barbara, is the corresponding author. To access the embargoed study:  Visit our For The Media website at this link https://media.jamanetwork.com/  (doi:10.1001/jamanetworkopen.2020.37129) Editor's Note: The article includes funding/support disclosures. Please see the article for additional information, including other authors, author contributions and affiliations, conflict of interest and financial disclosures, and funding and support. INFORMATION: Media advisory: ...

National trends in us otolaryngology surgical volume early in COVID-19 pandemic

2021-02-11
What The Study Did: Changes in otolaryngology surgical volumes in the United States early on in the COVID-19 pandemic are described in this study. Authors: Anirudh Saraswathula, M.D., M.S., of Johns Hopkins University School of Medicine in Baltimore, is the corresponding author. To access the embargoed study: Visit our For The Media website at this link https://media.jamanetwork.com/ (doi:10.1001/jamaoto.2020.5472) Editor's Note: Please see the article for additional information, including other authors, author contributions and affiliations, conflict of interest ...

LAST 30 PRESS RELEASES:

Salk scientist Joseph Ecker awarded McClintock Prize for Plant Genetics and Genome Studies

ADHD: Women are diagnosed five years later than men, despite symptoms appearing at the same age.

Power plants may emit more pollution during government shutdowns

Increasing pressures for conformity de-skilling and demotivating teachers, study warns

Researchers develop smarter menstrual product with potential for wearable health monitoring

Microwaves for energy-efficient chemical reactions

MXene current collectors could reduce size, improve recyclability of Li-ion batteries

Living near toxic sites linked to aggressive breast cancer

New discovery could open door to male birth control

Wirth elected Fellow of American Physical Society

The Journal of Nuclear Medicine Ahead-of-Print Tip Sheet: October 10, 2025

Destined to melt

Attitudes, not income, drive energy savings at home

The playbook for perfect polaritons

‘Disease in a dish’ study of progressive MS finds critical role for unusual type of brain cell

Solar-powered method lights the way to a ‘de-fossilized’ chemical industry

Screen time linked to lower academic achievement among Ontario elementary students

One-year outcomes after traumatic brain injury and early extracranial surgery in the TRACK-TBI Study

Enduring outcomes of COVID-19 work absences on the US labor market

Affirmative action repeal and racial and ethnic diversity in us medical school admissions

Cancer progression illuminated by new multi-omics tool

Screen time and standardized academic achievement tests in elementary school

GLP-1RA order fills and out-of-pocket costs by race, ethnicity, and indication

Study finds HEPA purifiers alone may not be enough to reduce viral exposure in schools

UVA Health developing way to ID people at risk of dangerous lung scarring even before symptoms appear

How can we know when curing cancer causes myocarditis?

Male infertility in Indian men linked to lifestyle choices and hormonal imbalances

An acoustofluidic device for sample preparation and detection of small extracellular vesicles

The advent of nanotechnology has ushered in a transformative era for oncology, offering unprecedented capabilities for targeted drug delivery and controlled release. This paradigm shift enhances thera

A prototype LED as thin as wallpaper — that glows like the sun

[Press-News.org] Hubble uncovers concentration of small black holes