Tuesday, March 19, 2024

SPACE

Largest-ever map of universe’s active supermassive black holes released


The new map includes around 1.3 million quasars from across the visible universe and could help scientists better understand the properties of dark matter


Peer-Reviewed Publication

SIMONS FOUNDATION

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AN INFOGRAPHIC EXPLAINING THE CREATION OF A NEW MAP OF AROUND 1.3 MILLION QUASARS FROM ACROSS THE VISIBLE UNIVERSE.

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CREDIT: ESA/GAIA/DPAC; LUCY READING-IKKANDA/SIMONS FOUNDATION; K. STOREY-FISHER ET AL. 2024




Astronomers have charted the largest-ever volume of the universe with a new map of active supermassive black holes living at the centers of galaxies. Called quasars, the gas-gobbling black holes are, ironically, some of the universe’s brightest objects.

The new map logs the location of about 1.3 million quasars in space and time, the furthest of which shone bright when the universe was only 1.5 billion years old. (For comparison, the universe is now 13.7 billion years old.)

“This quasar catalog is different from all previous catalogs in that it gives us a three-dimensional map of the largest-ever volume of the universe,” says map co-creator David Hogg, a senior research scientist at the Flatiron Institute’s Center for Computational Astrophysics in New York City and a professor of physics and data science at New York University. “It isn’t the catalog with the most quasars, and it isn’t the catalog with the best-quality measurements of quasars, but it is the catalog with the largest total volume of the universe mapped.”

Hogg and his colleagues present the map in a paper published March 18 in The Astrophysical Journal. The paper’s lead author, Kate Storey-Fisher, is a postdoctoral researcher at the Donostia International Physics Center in Spain.

The scientists built the new map using data from the European Space Agency’s Gaia space telescope. While Gaia’s main objective is to map the stars in our galaxy, it also inadvertently spots objects outside the Milky Way, such as quasars and other galaxies, as it scans the sky.

“We were able to make measurements of how matter clusters together in the early universe that are as precise as some of those from major international survey projects — which is quite remarkable given that we got our data as a ‘bonus’ from the Milky Way–focused Gaia project,” Storey-Fisher says.

Quasars are powered by supermassive black holes at the centers of galaxies and can be hundreds of times as bright as an entire galaxy. As the black hole’s gravitational pull spins up nearby gas, the process generates an extremely bright disk and sometimes jets of light that telescopes can observe.

The galaxies that quasars inhabit are surrounded by massive halos of invisible material called dark matter. By studying quasars, astronomers can learn more about dark matter, such as how much it clumps together.

Astronomers can also use the locations of distant quasars and their host galaxies to better understand how the cosmos expanded over time. For example, scientists have already compared the new quasar map with the oldest light in our cosmos, the cosmic microwave background. As this light travels to us, it is bent by the intervening web of dark matter — the same web mapped out by the quasars. By comparing the two, scientists can measure how strongly matter clumps together.

“It has been very exciting to see this catalog spurring so much new science,” Storey-Fisher says. “Researchers around the world are using the quasar map to measure everything from the initial density fluctuations that seeded the cosmic web to the distribution of cosmic voids to the motion of our solar system through the universe.”

The team used data from Gaia’s third data release, which contained 6.6 million quasar candidates, and data from NASA’s Wide-Field Infrared Survey Explorer and the Sloan Digital Sky Survey. By combining the datasets, the team removed contaminants such as stars and galaxies from Gaia’s original dataset and more precisely pinpointed the distances to the quasars. The team also created a map showing where dust, stars and other nuisances are expected to block our view of certain quasars, which is critical for interpreting the quasar map.

“This quasar catalog is a great example of how productive astronomical projects are,” says Hogg. “Gaia was designed to measure stars in our own galaxy, but it also found millions of quasars at the same time, which give us a map of the entire universe.”


Map Video [VIDEO] | 

This graphic representation of the map shows the location of quasars from our vantage point, the center of the sphere. The regions empty of quasars are where the disk of our galaxy blocks our view. Quasars with larger redshifts are further away from us.

CREDIT

ESA/Gaia/DPAC; Lucy Reading-Ikkanda/Simons Foundation; K. Storey-Fisher et al. 2024


ABOUT THE FLATIRON INSTITUTE

The Flatiron Institute is the research division of the Simons Foundation. The institute's mission is to advance scientific research through computational methods, including data analysis, theory, modeling and simulation. The institute's Center for Computational Astrophysics creates new computational frameworks that allow scientists to analyze big astronomical datasets and to understand complex, multi-scale physics in a cosmological context.

Comet that passes by Earth once every 71 years visible in night sky


The 12P/Pons-Brooks can be spotted in the night sky with binoculars or a telescope, but may even be visible to the naked eye in the coming weeks.


Niamh Lynch
News reporter @niamhielynch
Saturday 16 March 2024

The 12P/Pons-Brooks comet as seen from Pico de las Nieves on Gran Canaria, Spain. 

Is it a bird? Is it a plane? No - it's a comet that has been spotted from Earth for the first time in 71 years.

The 12P/Pons-Brooks comet is growing brighter and is now visible in the night sky - but you'll still need binoculars or a telescope to see it.

Image:A composite photo of the comet taken in Cumbria. Pic: PA/Stuart Atkinson

However, it may be visible to the naked eye in the coming weeks.

It has already had several outbursts of activity, according to Dr Megan Argo, an astrophysicist at the University of Central Lancashire.

"If we're lucky, it may have another in the next few weeks as it passes through the sky," she said.

The comet, named after its discoverers Jean-Louis Pons and William Robert Brooks, spends most of its time in the outer reaches of the solar system, where it is very cold.

It comes back to the inner solar system - passing by Earth - every 71 years and is known as a periodic comet because of this.

As the comet gets close to the sun while passing through the inner solar system, the heat causes the ice to melt straight to gas - through a process called sublimation - and some of the material is lost from the surface.

"This gas forms both a cloud around the solid nucleus of the comet - known as the coma - and a tail of material that can stretch many millions of miles in space," Dr Argo said.

"The tail is made of gas and dust that has been pushed away from the comet by the power of the solar wind streaming from the sun, and this tail is the bit that can become spectacular in the sky as seen from Earth."

Dr Argo said that while 12P/Pons-Brooks is developing a nice tail, it is "not quite visible without binoculars or a telescope just yet".

For those looking to spot the comet, it is below - and slightly to the left - of the Andromeda Galaxy.

The best way to see the comet is to find a place with dark skies and no tall trees, buildings or hills to block the views, astronomers say.


Rensselaer researcher receives DOE grant to develop models that track the formation of black holes


$1.5 million grant supports the creation of surrogate machine learning models for extreme-scale distributed computing infrastructure


RENSSELAER POLYTECHNIC INSTITUTE

Christopher Carothers, Ph.D. 

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CHRISTOPHER CAROTHERS, PH.D.

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CREDIT: RENSSELAER POLYTECHNIC INSTITUTE




When a star goes supernova, a massive burst of neutrinos is the first signal that can escape the density of the collapsing star. Detecting and analyzing this phenomenon in real time would allow us insight into stellar dynamics and, potentially, black hole formation. Detection of these types of signals from modern physics detectors is notoriously hard and presents computational challenges that push the bounds of modern and next-generation computing. Transmitting and analyzing the data from the massive particle physics detectors to the next generation of extreme-scale computing will require detailed modeling of the networking, hardware, and leadership class computing systems. These models will allow researchers to find and optimize the computing pathways, configurations, and infrastructure topologies so that they can handle these massive data loads.

To meet these challenges, the Tachyon Project – named for a hypothetical atomic particle that travels faster than light – has been awarded $7.5 million from the U.S. Department of Energy (DOE) High Energy Physics (HEP) program to model, simulate, and validate the transport, transmission, and analysis of particle physics data using extreme-scale computing systems, artificial intelligence (AI), and machine learning (ML) techniques. Christopher Carothers, Ph.D., professor and director of Rensselaer Polytechnic Institute’s Center for Computational Innovations, which has been awarded $1.5 million of the total grant, will serve as principal investigator for the project.

Over the five years of the DOE grant, the Tachyon Project will utilize data and information from the Fermi National Accelerator Laboratory and Argonne National lab computing facilities. The project will model the entire distributed infrastructure required to transmit and analyze data from the international Deep Underground Neutrino Experiment (DUNE), hosted by Fermilab, to the computing facilities at the Argonne Leadership Computing Facility (ALCF) in near real time. It will do this by creating surrogate machine learning models trained on both historical facility data and massively parallel simulation data. This will enable scientists at Fermilab to predict and tune workflow performance, improve resiliency, and increase the rate of scientific discovery in both the experimental and computing fields.   

Joining Carothers in this research are co-PIs Kevin Brown, Argonne National Laboratory; Andrew Norman, Fermi National Accelerator Laboratory; Zhiling Lan, University of Illinois Chicago; Kwan-Liu Ma, UC Davis; Tanwi Mallick, Argonne National Laboratory; Robert Ross, Argonne National Laboratory; and Kai Shu, Illinois Institute of Technology.

About Rensselaer Polytechnic Institute:

Founded in 1824, Rensselaer Polytechnic Institute is America’s first technological research university. Rensselaer encompasses five schools, over 30 research centers, more than 140 academic programs including 25 new programs, and a dynamic community made up of over 6,800 students and 110,000 living alumni. Rensselaer faculty and alumni include upwards of 155 National Academy members, six members of the National Inventors Hall of Fame, six National Medal of Technology winners, six National Medal of Science winners, and a Nobel Prize winner in Physics. With nearly 200 years of experience advancing scientific and technological knowledge, Rensselaer remains focused on addressing global challenges with a spirit of ingenuity and collaboration. To learn more, please visit www.rpi.edu.

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