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Written by: Eleonora Troja, University of Rome Tor Vergata and Simone Dichiara, Penn State

Published: 01 January 2023

 

The Research Brief is a short take about interesting academic work.

The big idea

A bright flash of gamma rays from the constellation Boötes that lasted nearly one minute came from a kilonova, as we described in a new paper. This finding challenges what astronomers know about some of the most powerful events in the universe.

The unusual cosmic explosion was detected by the Neil Gehrels Swift observatory on Dec. 11, 2021, as the satellite orbited Earth. When astronomers pointed other telescopes at the part of the sky where this large blast of gamma rays – named GRB211211A – came from, they saw a glow of visible and infrared light known as a kilonova. The particular wavelengths of light coming from this explosion allowed our team to identify the source of the unusual gamma-ray burst as two neutron stars colliding and merging together.

Gamma rays are the most energetic form of electromagnetic radiation. In just a few seconds, a gamma-ray burst blasts out the same amount of energy that the Sun will radiate throughout its entire life. Gamma-ray bursts are the most powerful events in the universe, and astronomers think only two cosmic scenarios can produce gamma-ray bursts.

The most common sources are the deaths of stars 30 to 50 times more massive than the Sun. The catastrophic destruction of one these large stars is called a supernova. When they explode, the stars create black holes that consume the leftover debris. These black holes emit a jet of matter and electromagnetic radiation that moves at close to the speed of light. In moments after the black hole starts emitting this high-energy stream of matter and radiation, the jet produces a burst of gamma rays that can last for minutes.

Kilonovae are the second type of events associated with gamma-ray bursts. Kilonovae occur when a neutron star merges with another neutron star or is consumed by a black hole. Neutron stars are rather small stars – about 1.4 to 2 times the mass of the Sun, though only dozens of miles across.

When two of these tiny, dense stars merge to produce a black hole, they leave very little material behind. Compared with the long-lasting feast a black hole gets after a supernova, kilonovae leave a black hole with little more than a snack that results in a gamma-ray burst that lasts only a second or two at most.

For over 20 years, astronomers thought that kilonovae accompanied short gamma-ray bursts and supernovae accompanied long ones. So when our team started looking at the wealth of data and images collected on the minute-long burst in December 2021, we expected to see a supernova. Much to our surprise, we found a kilonova.

Why it matters

Kilonovae are cosmic factories that create heavy metals, including gold, platinum, iodine and uranium. Because they enrich the chemical composition of the universe, kilonovae are critical to providing the basic ingredients for the formation of planets and life.

GRB211211A’s long duration contradicts existing theories of how gamma-ray bursts relate to supernovae and kilonovae. This finding shows that there is still a lot astronomers like us don’t understand about these powerful and important processes and suggests that there may be other ways the universe can produce heavy metals.

What still isn’t known

The initial images and data gathered on this interesting event look like a kilonova produced from the collision of two neutron stars. But the long-lasting burst of gamma rays throws doubt on what exactly happened. It is possible that one of the players was a rare neutron star with an incredibly powerful magnetic field – called a magnetar. The burst could also have been the result of a neutron star being torn apart by its companion black hole. Or astronomers could have just witnessed a new, previously unknown type of stellar crash.

What’s next

The few exotic stellar encounters that produce gamma-ray bursts can look very similar to one another across the electromagnetic spectrum. However, the unique gravitational wave signatures they produce could be the key to solving the enigma. The gravitational wave detectors LIGO, Virgo and KAGRA did not see GRB211211A, as they were all offline for improvements. If they can catch a long-duration gamma-ray burst after they begin operating again in 2023, the combination of gravitational wave and electromagnetic data may solve the mystery of this newly discovered event.

Eleonora Troja, Associate Professor of Astrophysics, University of Rome Tor Vergata and Simone Dichiara, Assistant Research Professor of Astrophysics, Penn State

This article is republished from The Conversation under a Creative Commons license. Read the original article.

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Written by: Elizabeth Larson

Published: 31 December 2022

LAKE COUNTY, Calif. — Lake County’s sheriff hung up his badge on Friday at the end of his second term.

Brian Martin stepped into retirement this week, just two months following his surprise announcement that he planned to leave office after having won a third term running unopposed in June.

Martin’s 28-year law enforcement career began in 1992 when he became a military police officer in the U.S. Army, serving in that capacity for five years. After he was honorably discharged in 1997, he joined the Pismo Beach Police Department.

He returned in 2005 to work in Lake County, where he had grown up in a family filled with public servants, including his father, Richard Martin, now retired after having been a Lake County Superior Court judge, and mother Joyce Campbell, a retired deputy district attorney for Lake County.

Martin, 51, went on to serve more than 15 years in Lake County law enforcement, including the last eight years as sheriff.

Earlier this month Martin received a resolution that Congressman Mike Thompson read into the congressional record honoring him for his contributions to Lake County and his leadership during several disasters that hit the county, including fires, floods and COVID-19.

The Board of Supervisors on Dec. 13 presented a proclamation to Martin, published below, in praise of his career and services to Lake County.

On Friday at 2:14 p.m., Martin had his last “10-10” call — indicating that he was off duty — from Central Dispatch. The call is posted on this page.

From Saturday through Monday, Capt. Chris Chwialkowski will be acting sheriff.

Then, on Jan. 2, Rob Howe will be sworn in as sheriff of Lake County, a role he will fill for the next two years.

The Board of Supervisors appointed Howe as sheriff on Dec. 20. He is a former sheriff’s office captain who has served as chief probation officer since March 2012.

The full text of the Board of Supervisors’ proclamation honoring Martin is below.


WHEREAS, being a dedicated Lake County public servant came naturally to Brian Martin, as he was surrounded by examples of public service: his father, the Honorable Judge Richard Martin, his mother, retired Deputy District Attorney for Lake County. His parents’ invaluable contributions to the County of Lake have set a high bar for both Brian and other community leaders. The values his parents instilled in him have been evident to everyone who has worked with Brian throughout his impressive career. Prior to starting his law enforcement career, Brian Martin joined the Army as a Military Police and served his country with honor for five years; and

WHEREAS, starting with his employment with Lake County on July 18, 2005, Brian Martin has always been respected and well-liked by his colleagues in local law enforcement, all the way back to his early days working for the Sheriff’s Department. He worked his way up to become a member of the Department’s Command Staff with the rank of Lieutenant and was eventually elected as the Sheriff-Coroner of Lake County and started in that position on January 6, 2015; and

WHEREAS, regardless of his rank or position, Brian Martin always demonstrated himself to be a dedicated public servant, reliable, hard-working and with the highest level of integrity and ethics. He is known as being fair and even-handed. He is also known for speaking up and speaking out with honesty and sincerity on behalf of the Lake County residents he serves; and

WHEREAS, Brian Martin’s election as Sheriff-Coroner brought ethical leadership, stability, and public trust to the Sheriff’s Department at a critical time when it was urgently needed. His skills as a leader were invaluable to the County during a series of catastrophic wildfires and other emergencies that occurred during his tenure as Sheriff-Coroner. Like his parents before him, Brian Martin has set a high bar of what to expect from our County Sheriff-Coroner. Brian and his spouse, Crystal, both are public servants serving their communities and instilling in their children and their communities the value of public service.

NOW, THEREFORE, BE IT PROCLAIMED that the Board of Supervisors of the County of Lake does hereby commend Brian Martin for his 15 years of service to the County of Lake and to the residents of Lake County, and extends our appreciation for his dedication and hard work, and wish him the best in the future.

SIGNED: Eddie Crandell, Chair, Board of Supervisors

ATTEST: Susan Parker, Clerk to the Board of Supervisors

Email Elizabeth Larson at This email address is being protected from spambots. You need JavaScript enabled to view it.. Follow her on Twitter, @ERLarson, or Lake County News, @LakeCoNews.

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Written by: Cal Fire

Published: 31 December 2022

In looking back on fire news in California over the past year, Cal Fire is sharing six important things about 2022.

Those topics are shared below.

No. 1: Reflecting on a year of progress and resilience, California experienced an 85% reduction in acres burned and a 78% reduction in structures destroyed in 2022

While Mother Nature played a critical role, strategic investments in firefighting equipment, aerial resources, fuels reduction and forest management projects, and the tireless hard work of firefighters and local communities also came together to help 2022 experience significantly fewer acres burned than in previous years.

Watch Cal Fire Director Joe Tyler in the video discuss the year’s highlights.

No. 2: A new demonstration forest and more than 2,500 acres were added statewide, furthering momentum for important forest research, restoration, and stewardship work

California's demonstration state forests help show the world how restoration, conservation and stewardship come together to provide critical research and healthy forests during the age of climate change.

Cal Fire furthered this important work this year and thank our many partners and adjacent communities that help make it happen.

No. 3: Cal Fire law enforcement officers helped stop fires before they started through a record number of arson arrests

Through the committed work of Cal Fire law enforcement officers and diligent community members, more than 160 arson arrests were made this year following extensive investigations.

With a majority of all wildfires being human-caused in California, this year's record-setting number makes a significant impact towards combatting the potential for human-caused megafires.

Since 2016, Cal Fire law enforcement officers have arrested more than 700 suspected arsonists.



No. 4: The first night flying missions hit the sky, providing California another important tool in the firefighting toolbox

Cal Fire continues to add new technology and innovative solutions to the range of firefighting tools available to us.

One of these tools, when conditions and operations allow, is the ability to attack fires at night from the air.

In the video above, see first-hand how this works and the added capacity it provides.



No. 5: Important updates were made to California’s Fire Hazard Severity Zone map, now open for public comment

After years of planning and collaboration with fire scientists, firefighters, stakeholders and local community partners, the new and updated map reflects changes in fire hazard now experienced throughout California in rural or unincorporated areas.

And there are many ways to stay informed and provide public comment. Learn more at the link below.

No. 6: Millions were distributed to California communities to strengthen partnerships, shade schoolyards and neighborhoods, and prepare for and prevent wildfire

And applications are now open for 2023. Learn more about the amazing work these grants make possible and what's available for your community.