Pulsar timing arrays are on track to detect long-period gravitational waves by measuring their effects on the light-travel times of pulses from rotating neutron stars (pulsars). NANOGrav monitors a set of pulsars that together form a Galactic scale gravitational-wave observatory. Our detector will be used to study supermassive black hole binaries in order to understand the morphology, kinematics, gas content, and feedback mechanisms of galaxies. Pulsars can also be used to detect gravitational waves from topological defects in space time called cosmic strings, which are predicted by some high energy physics models.
Summary: New results from NANOGrav – the North American Nanohertz Observatory for Gravitational Waves – establish astrophysically significant limits in the search for low-frequency gravitational waves. This result provides insight into how often galaxies merge, and how those merging galaxies evolve over time. To obtain this result, scientists required an exquisitely precise, nine-year pulsar-monitoring campaign conducted by two of the most sensitive radio telescopes on Earth, the Green Bank Telescope in West Virginia and the Arecibo Observatory in Puerto Rico.
NANOGrav congratulates our LIGO colleagues on their discovery of gravitational waves from a binary black hole system. This result is a major milestone, not only in the field of gravitational-wave astronomy, but in the history of science!
LIGO and NANOGrav are complementary efforts covering different regions of the gravitational-wave spectrum. Pulsar timing arrays like NANOGrav are sensitive to gravitational waves with periods of years, while LIGO is sensitive to waves with periods near one-hundredth of a second or less. Other projects are working to detect the Hubble-length primordial waves that leave an imprint in the polarization of the Cosmic Microwave Background (CMB), while future space-based instruments such as eLISA are tuned to detect waves with hour-long periods. Each of these experiments explores different time scales, originating from a wide range of objects and phenomena in the universe.
With the LIGO discovery, the field of observational gravitational-wave astronomy is now a reality. NANOGrav looks forward to detection of many additional, and other types of, sources with results from LIGO and other ground-based instruments, as well as the CMB and eventually the space-based gravitational-wave communities. Together we are opening a completely new window on the Universe.
The collaboration is excited to announce a new public data release for NANOGrav timed pulsars. The paper was published in ApJ 831,65 and can be found on the archive at arXiv:1505.07540. Data can be obtained at data.nanograv.org.
This dataset has produced a variety of NANOGrav analysis papers including:
Gravitational wave astronomy is at the cutting edge of modern science and is about to open a whole new window on our Universe.
About this image: An artist's impression of two merging black holes. The blue waves represent gravitational waves, which actually emit no light. NANOGrav will be sensitive to systems like this. Image credit: NASA
We use exotic objects called pulsars to create a "cosmic global positioning system".
About this image: A schematic diagram of a pulsar timing array. NANOGrav uses this technique to detect the influence of gravitational waves on the Earth.
We are a diverse group of astronomers, physicists, and engineers comprised of senior scientists, postdoctoral fellows, and graduate and undergraduate students.
About this image: NANOGrav members gather for a group photo at our Fall 2012 meeting at Oberlin College.
NANOGrav members are located at over a dozen institutions throughout North America, and we collaborate with colleagues from around the world.
About this image: The location of NANOGrav member institutions across the United States and Canada.
We predict that we will detect gravitational waves within the next decade. But detection is only the first step towards ushering in a new era of gravitaional wave astronomy.
About this image: In this graph, solid lines represent the sensitivity of current and future gravitational wave experiments (regions above the lines can be detected). The shaded regions show the expected strength of gravitational waves from various sources according to different models. Pulsar timing arrays are towards the left, at the lowest frequencies, and are expected to make a detection of supermassive black holes or cosmic strings by no later than 2020.
Joseph Romano has written an article based on the metronome PTA demo developed by members of the NANOGrav education and outreach team. It was recently published in the Mexican popular science magazine Conversus. Check out the article here.
Nipuni Palliyaguru's paper "Correcting for Interstellar Scattering Delay in High-precision Pulsar Timing: Simulation Results" - was published in ApJ.
The West Virginia University Research Corporation (WVURC) invites applications for a postdoctoral researcher who is dedicated to outreach, astronomy education, and astrophysics research.in the Department of Physics and Astronomy at West Virginia University (WVU). The successful applicant will spend roughly half of their time providing support for the Pulsar Search Collaboratory program, managed jointly with colleagues at the National Radio Astronomy Observatory in Green Bank, WV. This program will involve high-school students throughout the United States in pulsar searching with the Green Bank Telescope (GBT). More information about the position can be found here.
The West Virginia University Research Corporation (WVURC) invites applications for a postdoctoral researcher in pulsar astrophysics in the Department of Physics and Astronomy at West Virginia University (WVU). This position is one of several postdoctoral positions that are funded through the newly established North American Nanohertz Observatory for Gravitational Waves (NANOGrav) Physics Frontier Center (PFC); see http://nanograv.org. More information about the position can be found here.
Laura Sampson, Neil Cornish and Sean McWilliams have had their paper entitled Constraining the Solution to the Last Parsec Problem with Pulsar Timing accepted for publication in Physical Review D.
Maura McLaughlin was recently named an Eberly Family Distinguished Professor of Physics and Astronomy" at West Virginia University
This material is based in part on work supported by the National Science Foundation under Grant Number 968296. Any opinions, findings and conclusions or recommendations expressed in this material are those of the author(s) and do not necessarily reflect the views of the National Science Foundation.