Physics of the Cosmos
Exploring fundamental questions regarding the physical forces of the universe

Multimessenger Astrophysics
Science Analysis Group
(MMA SAG)

Multimessenger Astrophysics Decadal Survey White Paper Projects

List of Multimessenger Astrophysics Science white papers submitted by community members to the MMA SAG and Astro2020

  1. A Summary of Multimessenger Science with Neutron Star Mergers
  2. Details

    Lead Author Eric Burns
    Lead Author email eric.burns@nasa.gov
    Coauthors: A. Tohuvavohu, C. A. Wilson-Hodge, D. Eichler, C. Fryer, J. Buckley, D. Radice, B. D. Metzger, Bing Zhang, K. Murase, John Tomsick, T. Dal Canton, B. Cenko
    Key words  
    Link to white paper / draft PDF
    Abstract: Neutron star mergers, referring to both binary neutron star and neutron star black hole mergers, are the canonical multimessenger events. They have been detected across the electromagnetic spectrum, have recently been detected in gravitational waves, and are likely to produce neutrinos over several decades in energy. The non-thermal prompt and afterglow emission of short gamma-ray bursts and the quasi-thermal emission from the radioactively powered kilonovae provide distinct insights into the physics of neutron star mergers. When combined with direct information on coalescence from gravitational waves and neutrinos these sources may become the best understood astrophysical transients. Multimessenger observations of these cataclysmic events will enable precision cosmology and unique tests of fundamental physics, the origin of heavy elements, the behavior of relativistic jets, and the equation of state of supranuclear matter, and confirm some sources of gravitational waves and astrophysical neutrinos. In this white paper we present a summary of the science discoveries made possible by multimessenger observations of neutron star mergers and provide recommendations to maximize science in the new era of time-domain, multimessenger astronomy.

  3. Opportunities for Multimessenger Astronomy in the 2020s
  4. Details

    Lead Author Eric Burns
    Lead Author email eric.burns@nasa.gov
    Coauthors: A. Tohuvavohu, J. M. Bellovary, E. Blaufuss, T. J. Brandt, S. Buson, R. Caputo, S. B. Cenko, N. Christensen, J. W. Conklin, F. D'Ammando, K.E.S. Ford, A. Franckowiak, C. Fryer, C. M. Hui, K. Holley-Bockelmann, T. Jaffe, T. Kupfer, M. Karovska, B. D. Metzger, J. Racusin, B. Rani, M. Santander, J. Tomsick, C. Wilson-Hodge
    Key words  
    Link to white paper / draft PDF
    Abstract: Electromagnetic observations of the sky have been the basis for our study of the Universe for millennia, cosmic ray studies are now entering their second century, the first neutrinos from an astrophysical source were identified three decades ago, and gravitational waves were directly detected only four years ago. Detections of these messengers are now common. Astrophysics will undergo a revolution in the 2020s as multimessenger detections become routine. The 8th Astro2020 Thematic Area is Multimessenger Astronomy and Astrophysics, which includes the identification of the sources of gravitational waves, astrophysical and cosmogenic neutrinos, cosmic rays, and gamma-rays, and the coordinated multimessenger and multiwavelength follow-ups. Identifying and characterizing multimessenger sources enables science throughout and beyond astrophysics. Success in the multimessenger era requires: (i) sensitive coverage of the non-electromagnetic messengers, (ii) full coverage of the electromagnetic spectrum, with either fast-response observations or broad and deep high-cadence surveys, and (iii) improved collaboration, communication, and notification platforms.

  5. Multi-Physics of AGN Jets in the Multi-Messenger Era
  6. Details

    Lead Author Bindu Rani
    Lead Author email bindu.rani@nasa.gov
    Coauthors: M. Baring, M. Böttcher, S. Dimitrakoudis, Z. Gan, D. Giannios, D. H. Hartmann, T. P. Krichbaum, A. P. Marscher, A. Mastichiadis, K. Nalewajko, R. Ojha, D. Paneque, C. Shrader, L. Sironi, A. Tchekhovskoy, D. J. Thompson, N. Vlahakis, T. M. Venters
    Key words  
    Link to white paper / draft PDF
    Abstract: This new era of multi-messenger astronomy, which will mature in the next decade, offers us the unprecedented opportunity to combine more than one messenger to solve some long-standing puzzles of AGN jet physics. We advocate the support to future instruments with large effective areas, excellent timing resolution, and wide fields of view.

  7. A Unique Messenger to Probe Active Galactic Nuclei: High-Energy Neutrinos
  8. Details

    Lead Author Marcos Santander
    Lead Author email jmsantander@ua.edu
    Coauthors: Sara Buson, Ke Fang, Azadeh Keivani, Thomas Maccarone, Kohta Murase, Maria Petropoulou, Ignacio Taboada, Nathan Whitehorn
    Key words  
    Link to white paper / draft PDF
    Abstract: We advocate for a multi-messenger approach that combines high-energy neutrino and broad multi-wavelength electromagnetic observations to study AGN during the coming decade. The unique capabilities of these joint observations promise to solve several long-standing issues in our understanding of AGN as powerful cosmic accelerators.

  9. Multi-Messenger Astrophysics With Pulsar Timing Arrays
  10. Details

    Lead Author Luke Zoltan Kelley & Maria Charisi
    Lead Author email LZKelley@northwestern.edu, mcharisi@caltech.edu
    Coauthors: S. Burke-Spolaor, J. Simon, L. Blecha, T. Bogdanovic, M. Colpi, J. Comerford, D. D'Orazio, M. Dotti, M. Eracleous, M. Graham, J. Greene, Z. Haiman, K. Holley-Bockelmann, E. Kara, B. Kelly, S. Komossa, S. Larson, X. Liu, C.-P. Ma, S. Noble, V. Paschalidis, R. Rafikov, V. Ravi, J. Runnoe, A. Sesana, D. Stern, M. A. Strauss, V. U, M. Volonteri, & the NANOGrav Collaboration
    Key words  
    Link to white paper / draft PDF
    Abstract: Pulsar timing arrays (PTAs) are on the verge of detecting low-frequency gravitational waves (GWs) from supermassive black hole binaries (SMBHBs). With continued observations of a large sample of millisecond pulsars, PTAs will reach this major milestone within the next decade. Already, SMBHB candidates are being identified by electromagnetic surveys in ever-increasing numbers; upcoming surveys will enhance our ability to detect and verify candidates, and will be instrumental in identifying the host galaxies of GW sources. Multi-messenger (GW and electromagnetic) observations of SMBHBs will revolutionize our understanding of the co-evolution of SMBHs with their host galaxies, the dynamical interactions between binaries and their galactic environments, and the fundamental physics of accretion. Multi-messenger observations can also make SMBHBs 'standard sirens' for cosmological distance measurements out to z ≃ 0.5. LIGO has already ushered in breakthrough insights in our knowledge of black holes. The multi-messenger detection of SMBHBs with PTAs will be a breakthrough in the years 2020–2030 and beyond, and prepare us for LISA to help complete our views of black hole demographics and evolution at higher redshifts.

  11. A Summary of Multimessenger Science with Galactic Binaries
  12. Details

    Lead Author Thomas Kupfer
    Lead Author email tkupfer@ucsb.edu
    Coauthors: Mukremin Kilic, Tom Maccarone, Eric Burns, Chris L. Fryer, Colleen A. Wilson-Hodge
    Key words  
    Link to white paper / draft PDF
    Abstract: Galactic binaries with orbital periods less than ≈1 hr are strong gravitational wave sources in the mHz regime, ideal for the Laser Interferometer Space Antenna (LISA). In fact, theory predicts that LISA will resolve tens of thousands of Galactic binaries individually with a large fraction being bright enough for electromagnetic observations. This opens up a new window where we can study a statistical sample of compact Galactic binaries in both, the electromagnetic as well the gravitational wavebands. Using multi-messenger observations we can measure tidal effects in detached double WD systems, which strongly impact the outcome of WD mergers. For accreting WDs as well as NS binaries, multi-messenger observations give us the possibility to study the angular momentum transport due to mass transfer. In this white paper we present an overview of the opportunities for research on Galactic binaries using multi-messenger observations and summarize some recommendations for the 2020 time-frame.

  13. Core-Collapse Supernovae and Multi-Messenger Astronomy
  14. Details

    Lead Author Chris Fryer
    Lead Author email fryer@lanl.gov
    Coauthors: E. Burns, Pete Roming, Sean Couch, Marek Szczepanczyk, Pat Slane, Irene Tamborra, Reto Trappitsch
    Key words  
    Link to white paper / draft PDF
    Abstract: Multi-messenger diagnostics for core-collapse supernovae (CCSN) have been used for over half a century when astronomers began using dust grains to probe the yields from supernovae. But the concurrent neutrino and electromagnetic observations of SN 1987A, a core-collapse supernova in the Large Magellanic Cloud, cemented the importance of multi-messenger diagnostics for these transients. Although rare in the Milky Way where supernovae can be probed by multiple messengers, the science enabled in each event is enormous. Most of the gravitational energy released during collapse is emitted in MeV neutrinos that should be detectable within a few Mpc with next generation (NG) neutrino experiments. They may also be detected by future gravitational wave (GW) interferometers. Including dust grains (and other nucleosynthetic yield probes), cosmic rays and high-energy neutrinos that probe shocks, and a broad range of thermal and non-thermal photon emission, these messengers probe nearly all aspects of the supernova physics and its progenitor evolution. The multitude of diagnostics from a nearby supernova will allow us to tightly constrain our theories to maximize what we can learn about the universe from more distant, but less-well diagnosed, supernovae.

  15. Multi-Messenger Astrophysics Opportunities with Stellar-Mass Binary Black Hole Mergers
  16. Details

    Lead Author Peter Shawhan
    Lead Author email pshawhan@umd.edu
    Coauthors: Federico Fraschetti, Chris Fryer, Steven L. Liebling, Rosalba Perna, Péter Veres, Bing Zhang
    Key words  
    Link to white paper / draft PDF
    Abstract: The first gravitational-wave (GW) signal detected by LIGO, GW150914, was produced by the inspiral and merger of a pair of black holes (BHs) with masses of about 36 and 30 Msun, presumed to be the remnants of massive stars. That discovery introduced us to a population of fairly heavy stellar-mass binary black hole (sBBH) systems, and a total of ten sBBH mergers have been confidently detected in the first two observing runs of Advanced LIGO and Advanced Virgo. Many more will be detected as the sensitivities of LIGO and Virgo improve and as more detectors (KAGRA in Japan, and LIGO-India) join the network by the mid-2020s. The enlarged network also will be able to localize events better, so that about half of the detected events will be localized to ~10 deg2 or better at 90% confidence. Complementing the sBBH events, the binary neutron star merger GW170817 was a watershed for multi-messenger astrophysics (MMA). It featured a strong GW signal followed closely by a gamma-ray burst, a rich "kilonova" signature in the optical and infrared bands, and ultimately a multiwavelength afterglow which brightened over a period of months before fading. Those emissions are understood to have come from disrupted neutron star matter that was ejected, some of which fell back to form an accretion disk and power a relativistic jet. Of course, that source of matter is absent when two black holes merge, and so the conventional view of sBBH mergers is that there should not be enough matter present to produce a detectable electromagnetic (EM) transient. However, there are a number of mechanisms for producing such a counterpart, outlined below, and in fact, a weak gamma-ray transient signal was recorded by the Fermi Gamma-ray Burst Monitor (GBM) less than a second after GW150914. The statistical significance was less than 3 sigma, and no similar signal has been identified after other sBBH mergers so far, so it remains an intriguing but inconclusive hint of the possibility of gamma-ray emission from sBBH mergers. Our goals in this white paper are to 1) outline possible physical mechanisms for multi-messenger emission from sBBH mergers, and 2) describe the capabilities needed to either detect such emission or place substantive limits which can be translated into physical constraints.

  17. AGN (and other) astrophysics with Gravitational Wave Events
  18. Details

    Lead Author K. E. Saavik Ford
    Lead Author email sford@amnh.org
    Coauthors: Imre Bartos, Barry McKernan, Zoltan Haiman, Alessandra Corsi, Azadeh Keivani, Szabolcs Marka, Rosalba Perna, Matthew Graham, Nicholas P. Ross, Daniel Stern, Jillian Bellovary, Emanuele Berti, Matthew O'Dowd, Wladimir Lyra, Mordecai-Mark Mac Low, Zsuzsanna Marka, Endorsed by: Brian D. Metzger, Filippo D'Ammando, Brian Humensky, Richard O'Shaughnessy, Peter Meszaros, Nathan W. C. Leigh, Margarita Karovska, Peter Shawhan, Steven L. Liebling, Paolo Coppi
    Key words  
    Link to white paper / draft PDF
    Abstract: The stellar mass binary black hole (sBBH) mergers presently detected by LIGO may originate wholly or in part from binary black hole mergers embedded in disks of gas around supermassive black holes. Determining the contribution of these active galactic nucleus (AGN) disks to the sBBH merger rate enables us to uniquely measure important parameters of AGN disks, including their typical density, aspect ratio, and lifetime, thereby putting unique limits on an important element of galaxy formation. For the first time, gravitational waves will allow us to reveal the properties of the hidden interior of AGN disks, while electromagnetic radiation (EM) probes the disk photosphere. The localization of sBBH merger events from LIGO is generally insufficient for association with a single EM counterpart. However, the contribution to the LIGO event rate from rare source types (such as AGNs) can be determined on a statistical basis. To determine the contribution to the sBBH rate from AGNs in the next decade requires: 1) a complete galaxy catalog for the LIGO search volume, 2) strategic multi-wavelength EM follow-up of LIGO events and 3) significant advances in theoretical understanding of AGN disks and the behavior of objects embedded within them.

  19. MMA SAG: Thermonuclear Supernovae
  20. Details

    Lead Author Michael Zingale
    Lead Author email michael.zingale@stonybrook.edu
    Coauthors: Chris L. Fryer, Aimee Hungerford, Samar Safi-Harb, Reto Trappitsch, Robert Fisher, Alan Calder, Ken J. Shen
    Key words  
    Link to white paper / draft PDF
    Abstract: A Type Ia supernova (SN Ia) is an extremely energetic thermonuclear explosion, the brightness of which approaches that of its host galaxy. This immense luminosity has made them important cosmological distance probes, leading to the discovery of the acceleration of the expansion of the Universe. SN Ia are also important sites of nucleosynthesis and chemical enrichment of galaxies. Despite their importance to the field of astronomy, it is remarkable that today there is still no consensus on what is the underlying progenitor of SN Ia. Simulations have done a tremendous job in understanding the progenitors and their evolution and connecting to observations. With new surveys and space missions, the multimessenger observations of SN Ia will paint a clearer picture of the origin and mechanism of these events.
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Multidisciplinary Multimessenger Astrophysics Workshop in Baton Rouge, LA, 23 – 26 Sept 2024
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18 April 2024
Fermi Symposium Abstract Submission Open – Abstracts Due 1 May 2024
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First Announcement: Hybrid Joint NICER/IXPE Workshop, 20 July – 1 August 2024
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ROSES-24: Euclid General Investigator Final Text and Due Dates
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