Neil Gehrels facts for kids

Quick facts for kids Neil Gehrels
Born	Cornelis A. Gehrels (1952-10-03)October 3, 1952 Lake Geneva, Wisconsin, U.S.
Died	February 6, 2017(2017-02-06) (aged 64) Berwyn Heights, Maryland, U.S.
Occupation	Research scientist, professor, lecturer, author
Known for	Astrophysics research
Awards	Henry Draper Medal (2009)

Cornelis A. "Neil" Gehrels (October 3, 1952 – February 6, 2017) was an American astrophysicist. He was an expert in gamma-ray astronomy, which studies the most powerful explosions in space.

From 1995 until his death, he led the Astroparticle Physics Laboratory at NASA's Goddard Space Flight Center. He was famous for helping gamma-ray astronomy grow from early experiments to today's space telescopes. He was the main scientist for NASA's Swift mission. This mission was later named in his honor.

Early Life and Learning

Neil Gehrels was born in Lake Geneva, Wisconsin, on October 3, 1952. His father, Tom Gehrels, was also an astronomer. Neil grew up near telescopes and lived at McDonald Observatory. Later, his family moved to Tucson, Arizona, when he was 14.

He went to high school and then the University of Arizona. In 1976, he earned two bachelor's degrees, one in music and one in physics. He then got his Ph.D. in physics in 1982 from the California Institute of Technology. After that, he started working at NASA's Goddard Space Flight Center.

In 1980, he married Ellen Williams, who is a physics professor. They had two children, Thomas and Emily. Neil Gehrels passed away from pancreatic cancer on February 6, 2017, when he was 64 years old.

Amazing Career in Space Science

Neil Gehrels was a very important scientist at NASA. He became the Chief of the Astroparticle Physics Laboratory in 1995. He was the lead scientist for the Swift Gamma-Ray Burst Mission. This mission studies huge explosions in space called gamma-ray bursts.

He also had other big roles:

• He was the Project Scientist for the Compton Gamma Ray Observatory from 1991 to 2000.
• He was a Deputy Project Scientist for the Fermi Gamma-ray Space Telescope.
• He was the Project Scientist for the Nancy Grace Roman Space Telescope. This telescope will explore dark energy and exoplanets.

Besides his work at NASA, he was also a professor at the University of Maryland and Pennsylvania State University. His research focused on sudden, powerful events in the universe. These include gamma-ray bursts, supernovas (exploding stars), and flares from active galaxies. He helped turn gamma-ray astronomy into a major field of study.

In 2013, he was chosen to lead the Astronomy Section of the National Academy of Sciences. He wrote over 600 scientific papers. These papers have been used by other scientists many times. His work helped discover where short gamma-ray bursts come from. He also studied gamma-ray bursts at the very edge of the visible universe.

Exploring the Universe

Neil Gehrels was an astrophysicist with many interests. He mainly studied high-energy events in space. These include exploding stars, gamma-ray bursts, and stars that get torn apart by black holes. He also helped build new tools for observing space.

Studying with Voyager

For his graduate studies, Neil Gehrels worked on the Voyager mission. He helped test the cosmic ray instrument on the Voyager spacecraft. Later, he analyzed data from Voyager's fly-bys of Jupiter. Scientists expected to find mostly hydrogen and helium particles near Jupiter. But Gehrels found a lot of oxygen and sulfur. This discovery was linked to volcanoes on Jupiter's moon Io. These volcanoes were spewing oxygen and sulfur into space.

Observing Supernova 1987A

As a scientist at Goddard, Gehrels worked on a balloon experiment called GRIS. This experiment used special detectors to study gamma-ray sources. When Supernova 1987A was discovered, his team quickly prepared the instrument. They used it to observe gamma-rays from the supernova. Their observations showed that the supernova's explosion was not perfectly smooth. This was important evidence about how stars explode.

Compton Gamma Ray Observatory

Gehrels was the Project Scientist for the Compton Gamma Ray Observatory. This space telescope launched in 1991. It was one of NASA's "Great Observatories." It gave us the first full view of the gamma-ray sky.

Some of its discoveries included:

• Gamma-ray bursts are spread evenly across the sky, suggesting they come from far outside our galaxy.
• There are two types of gamma-ray bursts: short and long ones.
• Bright gamma-ray emissions from blazars (very active galaxies).
• Maps of gamma-rays from Al-26 decay in our galaxy. This showed where new elements were being made.
• Detailed maps of gamma-rays from positron annihilation in the galaxy, especially near the center.

Swift and Fermi Observatories

Neil Gehrels was the lead scientist for the Swift satellite. He was also a Deputy Project Scientist for the Fermi observatory. Swift launched in 2004. It was designed to study gamma-ray bursts and their afterglows.

Since 2009, Swift has become a tool for observing many types of changing objects. These include novae, supernovas, active galaxies, and magnetars. Gehrels led the proposal for Swift and oversaw its development. He also led important scientific papers from Swift. For example, he led the discovery paper about the afterglow and origin of short gamma-ray bursts.

For Fermi, Gehrels worked with many scientists to propose and build the mission. Fermi scans the entire sky for high-energy gamma rays every three hours. It has greatly changed our understanding of the gamma-ray sky. It has observed pulsars, active galaxies, gamma-ray bursts, and more.

The WFIRST Era

Gehrels joined the SNAP mission proposal in 2008. This mission later became the WFIRST. It is now known as the Nancy Grace Roman Space Telescope. This telescope is a wide-field infrared observatory.

In 2012, NASA decided to use a special telescope for WFIRST. It is similar to the Hubble Space Telescope. WFIRST will be able to see very faint objects with great detail. It will also have a special tool called a coronagraph. This tool helps block out starlight to see planets orbiting other stars.

WFIRST is being developed and is planned to launch in the mid-2020s. It will study dark energy, search for exoplanets, and explore general astrophysics. Neil Gehrels was the Project Scientist for WFIRST.

Other Important Work

Neil Gehrels also wrote several important papers that combined data analysis and theory:

• In 1986, he wrote a paper about how to find confidence limits for small numbers of events in space data. This is very useful for scientists.
• In 1993, he wrote a paper with his wife, Ellen Williams, about stable temperatures in hot, thin plasmas.
• In 1993, he suggested that the Geminga supernova might have caused the Local Bubble. This is a large, empty region in space near our solar system.
• In 2003, he wrote about how nearby supernovas could affect Earth's ozone layer.
• In 2015, he worked on a strategy for finding the sources of gravitational wave detections.

Awards and Honors

Neil Gehrels received many awards for his amazing work:

• 2017: Dan David Prize for astronomy
• 2016: Caltech Distinguished Alumni Award
• 2016: Milner Breakthrough Prize (with the LIGO Team for gravitational wave discovery)
• 2016: Honorary Fellow, Royal Astronomical Society
• 2015: An asteroid, 16000 Neilgehrels, was named after him.
• 2012: Fellow, American Association for the Advancement of Science
• 2010: Member, National Academy of Sciences
• 2009: Henry Draper Medal, National Academy of Sciences
• 2008: Member, American Academy of Arts and Sciences
• 2007: Bruno Rossi Prize, American Astronomical Society
• 2005: NASA Exceptional Scientific Achievement Medal

Selected Publications

• 2016, "Galaxy Strategy for LIGO-VIRGO Gravitational Wave Counterpart Searches", N. Gehrels, et al., ApJ, 820, 136.
• 2015, "WFIRST Science Definition Team Report", D. Spergel, N. Gehrels et al., arXiv 1503.03757.
• 2014, "GRB 130427A: A Nearby Ordinary Monster", A. Maselli, et al., Science, 343, 48.
• 2012, "Fermi Large Area Telescope Second Source Catalog", P. Nolan, et al., ApJ Supp, 199, 31.
• 2011, "Relativistic Jet Activities from the Tidal Disruption of a Star by a Massive Black Hole", D. N. Burrows, et al., Nature, 476, 421.
• 2009, "Gamma Ray Bursts in the Swift Era", N. Gehrels, E. Ramirez-Ruiz, & D. B. Fox, ARAA, 47, 567.
• 2006, "The New Gamma Ray Burst Classification Scheme from GRB 060614", N. Gehrels, et al., Nature, 444, 1044.
• 2006, "Detection, Huge Explosion in the Early Universe", G. Cusumano, et al., Nature, 440, 164
• 2005, "A Short GRB Apparently Associated with an Elliptical Galaxy at Redshift z=0.225", N. Gehrels, et al., Nature 437, 851.
• 2005, "Swift Detection of a Giant Flare from SGR 1806-20", D. Palmer, et al., Nature, 434, 1107.
• 2004, "The Swift Gamma Ray Burst Mission", N. Gehrels, et al., ApJ, 611, 105.
• 2003, "Ozone Depletion from Nearby Supernovae", N. Gehrels, C. Laird, C. Jackman, J. Cannizzo & B. Mattson, Astrophys. J., 585, 1169.
• 2000, "New Population of Galactic High Energy Gamma Ray Sources", N. Gehrels, D. Macomb, D. Bertsch, D. Thompson,& R. Hartman, Nature, 404, 363.
• 1999, "Revisiting the Black Hole", R. Blandford & N. Gehrels, Physics Today, June 1999 p. 40.
• 1998, "The New Gamma Ray Astronomy", N. Gehrels and J. Paul, Physics Today, February 1998 issue, p. 26.
• 1995, "Two Classes of Gamma-Ray Emitting Active Galactic Nuclei", C. Dermer & N. Gehrels, Astrophys. J., 447, 103.
• 1993, "The Geminga Supernova as a Possible Cause of the Local Interstellar Bubble", N. Gehrels & W. Chen, Nature 361, 706.
• 1993, "Temperatures of Enhanced Stability in Hot Thin Plasmas", N. Gehrels & E. D. Williams, ApJ, 418, L25.
• 1987, "Prospects for Observations of Nucleosynthetic Gamma-Ray Lines and Continuum from SN 1987A", N. Gehrels, C.J. MacCallum and M. Leventhal, ApJ, 320, L19.
• 1986, "Confidence Limits for Small Numbers of Events in Astrophysical Data", N. Gehrels, ApJ, 303, 336.
• 1985, "Instrumental Background in Balloon-Borne Gamma-Ray Spectrometers and Techniques for Its Reduction", N. Gehrels, NIM, A239, 324.
• 1983, "Energetic Oxygen and Sulfur in the Jovian Magnetosphere and Its Contribution to the Auroral Excitation", N. Gehrels and E. C. Stone, JGR, 88, 5537.