Press Releases

Scientists use Exotic Stars to Tune into Hum from Cosmic Symphony

Eureka Principal Investigator, Dr. Timothy Dolch, has been recognized for his part in the NANOGrav Physics Frontiers Center. The Press Release below outlines his contributions.

https://nanograv.org/news/15yrRelease

Researchers pioneer new technique that could help determine habitability of planets

Scientists at ASU, UC Boulder and other institutions, including Dr. Parke Loyd at Eureka Scientific, measured intensity of explosions on stellar surfaces using archival observations taken by Hubble Space Telescope.

Read the full press release at: https://news.asu.edu/20220913-how-habitable-are-planets-our-galaxy-hubble-space-telescope-research-has-produced-new-tool

ApJ paper: https://iopscience.iop.org/article/10.3847/1538-4357/ac80c1

The BAT AGN Spectroscopic Survey Data Release 2

Accreting supermassive black holes (SMBHs) or so-called active galactic nuclei (AGN) are among the most luminous sources of radiation in the universe and are thought to play an important role in the evolution of their host galaxies. The BAT AGN Spectroscopic Survey (BASS) is an all-sky survey of the brightest and most powerful hard X-ray emission in the sky that can trace even highly obscured AGN, and then observes them with a multitude of observations carried out with large allocations of time on advanced facilities (including VLT, Keck, Gemini, Chandra, NuSTAR, VLA, ALMA, etc.). As such, BASS provides a unique opportunity to study the low-redshift local population of powerful growing SMBHs and their hosts, as well as a crucial high-resolution, high-sensitivity benchmark for studying the cosmic evolution of SMBHs, anchoring deeper surveys that focus on higher redshifts.

The BASS Data Release 2 (DR2) special issue provides an unprecedented spectroscopic AGN survey in terms of spectral range, resolution, and sensitivity, including 1449 optical and 233 near-IR spectra for the brightest 858 ultrahard X-ray (14–195 keV) selected AGN across the entire sky at essentially all levels of obscuration. This release provides a highly complete set of key measurements (emission-line measurements and central velocity dispersions), with 99.9% of AGN with redshift measurements and 98% with black hole mass estimates (among unbeamed AGN outside the Galactic plane). The DR2 AGN sample represents a highly/uniquely complete census of nearby powerful AGN, spanning over 5 orders of magnitude in AGN bolometric luminosity, black hole mass, Eddington ratio, and obscuration. In this special issue, we provide nine papers covering the key measurements, data sets and catalogs, and scientific highlights from a series of DR2-based works pursued by the BASS team.

For more information please see the BAT AGN Spectroscopic Survey Data Release 2 on The Astrophysical Journal website.

***For release June 21, 2021 at 11am Eastern time US***

NSF Funds NANOGrav Physics Frontiers Center

The National Science Foundation (NSF) has renewed its support of the North American Nanohertz Observatory for Gravitational Waves (NANOGrav) with a $17 million grant over 5 years to operate the NANOGrav Physics Frontiers Center (PFC). The NANOGrav PFC will address a transformational challenge in astrophysics: the detection and characterization of low-frequency gravitational waves. The most promising sources of low-frequency gravitational waves are supermassive binary black holes that form via the mergers of massive galaxies. Additional low-frequency gravitational-wave sources include cosmic strings, inflation, and other early universe processes.

Our low-frequency gravitational-wave detectors are millisecond pulsars—rapidly spinning, superdense remains of massive stars that have exploded as supernovas. These ultra-stable stars are nature’s most precise celestial clocks, appearing to “tick” every time their beamed emissions sweep past the Earth, like the beacon on a lighthouse. Gravitational waves may be detected in the small but perceptible fluctuations—a few tens of nanoseconds over ten or more years—they cause in the measured arrival times at Earth of radio pulses from these millisecond pulsars.

“The NANOGrav PFC has made significant progress over the last five years, remaining at the frontier of fundamental physics research,” said Jim Shank, the program director for NSF’s PFC program. “The center now seems close to making a breakthrough discovery in gravitational waves and the way we perceive the universe.”

NANOGrav was founded in 2007 and at the time consisted of 17 members in the United States and Canada. Owing to support from the National Science foundation in the form of a PIRE (Partnerships for International Research and Education) award in 2010, and a PFC in 2015, NANOGrav has grown tremendously. It is now a highly-distributed collaboration with around 200 students and scientists at about 40 institutions around the world. Over the past few years, NANOGrav PFC students, postdocs, and senior personnel have pushed the frontiers of multi-messenger astrophysics, achieved an unprecedented sensitivity to low-frequency gravitational waves, and enabled a transition into astrophysically interesting territory: NANOGrav is now poised to detect low-frequency gravitational waves and use them to study the universe in a completely new way.

With Eureka Scientific, Inc., Dr. Timothy Dolch will be working on projects that involve tidying up the radio waves from pulsars, as these signals pass through ionized interstellar gas (the interstellar medium) before we receive them on Earth. He will also help the Education and Public Outreach working group expand and further develop its highly successful programs.

“This is an incredibly exciting time for gravitational wave astronomy,” Dolch says. “Almost a century ago when Karl Jansky inaugurated the field of radio astronomy, a new sky opened up. No one knew what radio telescopes were going to see in that sky. Pulsar timing arrays are on the verge of detecting signals from a part of the gravitational wave spectrum that has so far been invisible. Now that our sensitivity has dramatically improved, it remains all the more important to model and mitigate the effects of the interstellar medium on pulsar signals. Doing that also gives us bonus science! The interstellar medium is an important part of the universe to study for its own sake.”

Xavier Siemens, a physicist at Oregon State University, is the Principal Investigator (PI) for the project and will serve as Co-Director of the Center. Maura McLaughlin, an astronomer at West Virginia University and Co-Investigator of the project, will also serve as Co-Director.

NSF currently supports ten other PFCs, which range in research areas from theoretical biological physics and the physics of living cells to quantum information and nuclear astrophysics. By bringing together astronomers and physicists from across the United States and Canada to search for the telltale signature of gravitational waves buried in the incredibly steady ticking of distant pulsars, the NANOGrav PFC will advance the mission to “foster research at the intellectual frontiers of physics” and to “enable transformational advances in the most promising research areas.”

“We may already have seen the first hints of a gravitational-wave signal,” said Siemens. “This Center will ensure that researchers have the resources necessary to explore one of the most exciting frontiers in all of physics and astronomy.”

NANOGrav’s five-year program will make use of the unique capabilities and sensitivity of the Green Bank Telescope (GBT) in Green Bank, West Virginia. The GBT is located in the National Radio Quiet Zone, which protects the incredibly sensitive telescope from unwanted radio interference, enabling it to study pulsars and other astronomical objects. It also uses data from the Very Large Array (VLA) in New Mexico and the Canadian Hydrogen Intensity Mapping Experiment (CHIME) in Canada. In addition, NANOGrav will use legacy Arecibo Observatory data which will anchor combined future data sets, and greatly increase our sensitivity. The GBT, VLA, and Arecibo are all funded by the National Science Foundation. NANOGrav is also a member of the International Pulsar Timing Array (IPTA) collaboration, which aims to combine data from telescopes in North America, Europe, South Africa, India, and China to form the most sensitive pulsar timing dataset in the world.

NANOGrav’s ambitious science goals are accompanied by a comprehensive education and outreach program. McLaughlin explains that “the NANOGrav PFC involves students at all levels in our project. We aim to increase the involvement of high-school and undergraduate students in our project, specifically those who are traditionally under-presented in physics and astronomy, through innovative outreach and education programs.”

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For more information, please check NANOGrav’s website at: http://nanograv.org

*****END OF PRESS RELEASE*****

Solar Beacon

Observers of Solar Beacon will see two points of light, one on each tower top, that are bright as the Sun, but much smaller in size. Through an online interface, the public can schedule a time-based performance, during which the observed spots of light will appear to turn on and off. Because the reflected light is projected in a narrow beam a half degree across, the performance only appears to a region around the observer (e.g. 17m at 2 km), but it can be seen by anyone in the Bay Area who has direct view of the tops of the Golden Gate Bridge tower.

Solar Beacon acts as a bridge between Sun and Observer, Sky and Earth, Natural and Man-Made. In concept and design it has connected Artist and Scientist as well as Golden Gate Bridge Engineers and Aeronautical Engineers from the Space Sciences Laboratory at U.C. Berkeley. During the 75th Anniversary celebrations and the months that follow, the solar beam will directly link the line of sight between the public and the Bridge they love.

More information: http://solarbeacon.org/

Eureka: Astronomers Map Dark Matter in Massive Galaxies

THE FOLLOWING RELEASE WAS RECEIVED FROM EUREKA SCIENTIFIC IN OAKLAND, CALIFORNIA, AND IS FORWARDED FOR YOUR INFORMATION. (FORWARDING DOES NOT IMPLY ENDORSEMENT BY THE AMERICAN ASTRONOMICAL SOCIETY.) Rick Fienberg, AAS Press Officer: rick.fienberg@aas.org, +1 202-328-2010 x116.

** This release was previously distributed to journalists under an embargo that has since expired. {RTF} **

January 13, 2011

Contact: Dr. David Pooley Eureka Scientific +1 617-230-1098 davepooley@me.com

Images: http://www.deadlyastroninja.com/aas217/

ASTRONOMERS MAP OUT DARK MATTER IN MASSIVE GALAXIES

A team of astronomers led by Dr. David Pooley of Eureka Scientific has made an important determination of the amount of dark matter in massive galaxies using NASA's Chandra X-ray Observatory, providing independent evidence for the dark matter. In addition, these results help map out the distribution of dark matter in elliptical galaxies, which is vital in understanding both galaxy formation and the nature of dark matter.

The team studied 14 massive galaxies averaging about 6 billion light-years away, which appear almost directly in front of even more distant galaxies nearly three times farther away. Those more distant galaxies each harbor a supermassive black hole in the center, known as a quasar, which produces an enormous amount of light.

Because of the special configuration of these galaxies, the light from the distant quasar is "gravitationally lensed" by the intervening galaxy to produce four images of the quasar as seen from Earth's vantage point. According to Einstein's general theory of relativity, the gravitational field of a massive object, like one of these galaxies, can bend the path of light in its vicinity, acting as a lens and producing multiple images, or mirages, of the background object.

"We compared what those four images were supposed to look like according to lensing theory to what we actually saw with Chandra," said Dr. Pooley, who presented the results at the American Astronomical Society meeting in Seattle. "We found some major differences."

Based on the configuration of the images and the lensing galaxy, general relativity can predict the amount of matter needed in the lensing galaxy to produce the images of the background quasar. However, it does not address the form of the matter.

The team's explanation for the anomalies seen with Chandra lies in the makeup of the matter in the lensing galaxies. The aggregate gravitational field from all the matter in the lensing galaxy produces the effect strong enough to make the four distinct images of the background quasar. Along those four paths through the lensing galaxy, the light from the quasar can be further affected.

The stars in a galaxy have their own gravitational fields, which further perturb the light from the background quasar. "It's lensing on top of lensing," said Dr. Pooley. The degree to which the light is further affected is a sensitive function of the number of stars and the amount of dark matter at the locations in the galaxy where the quasar's light passes through.

A galaxy made entirely of stars, without any dark matter, would not produce what Dr. Pooley and his team saw with Chandra. Neither would a galaxy made entirely of dark matter. To produce what was observed, the galaxies must consist of approximately 85-95% dark matter in the regions where the background quasar's light passes through. Typically, those regions are located about 15,000 to 25,000 light-years from the centers of the lensing galaxies, similar to the distance of the Solar System from the center of the Milky Way.

"This is one of the most direct measurements of the amount of dark matter at a specific location in a galaxy," said Dr. Pooley. Other studies have determined the amount of dark matter in clusters of galaxies, such as the Bullet Cluster. In those cases, the dark matter being studied is mainly outside of the individual galaxies in the vast expanse between them. These results, on the other hand, are probing well inside individual galaxies.

Having determined the amount of matter in stars and dark matter at these locations, the team's next step is to determine the mass-to-light ratio. It will be the most direct measurement yet of an important quantity used in almost all areas of astronomy.

Earlier work in this area was presented by Professor Paul Schechter of the Massachusetts Institute of Technology and Professor Joachim Wambsganss of the University of Heidelberg, who worked with observations in optical light. Those results were ambiguous because the size of the region emitting the optical light was unknown, but these new X-ray results give a very clean determination of the amount of dark matter. Both Schechter and Wambsganss are members of the team presenting the X-ray results, along with Professor Saul Rappaport of MIT and Dr. Jeffrey Blackburne of Ohio State University.

These results will be further refined as more gravitationally lensed quasars are discovered and then observed with Chandra. The discovery of additional systems will be greatly aided by emerging large-area surveys undertaken by ground-based observatories, such as the Panoramic Survey Telescope & Rapid Response System project and the Large Synoptic Survey Telescope project.