Frontiers of Science Fellow
The Pennsylvania State University
The Louisiana State University
Sharif University of Technology
I study the astrophysical sources that create high-energy elementary particles, electromagnetic waves, and gravitational waves! The particles could be neutrinos which are rarely interacting and almost massless, or cosmic rays which are known to be charged particles such as protons or heavier nuclei. The electromagnetic waves span over a wide range of wavelengths from radio to gamma-rays. The gravitational waves come from the most exotic phenomena in the universe such as binary black hole mergers. All these messengers bring useful information from Space. We detect them with our telescopes on the ground and satellites in space.
I search for origins of high-energy neutrinos from the IceCube Neutrino Observatory by performing X-ray (using the NASA's Swift and NuStar satellite) and gamma-ray (using the NASA’s Fermi satellite) follow-up observations, whenever there is an exciting neutrino candidate. I also look for sources emitting both gravitational waves and high-energy neutrinos. Gravitational waves are publicly announced by the LIGO/Virgo collaborations (LVS; See the public user guide).
LIGO consist of two detectors, one in Livingston, Louisiana and one in Hanford, Washington. Virgo is located near Pisa in Italy. LVC is focused on direct detection of gravitational waves and study of fundamental physics of gravity. The first ever gravitational wave signal was detected in 2015 from the merger of binary black holes. This event was the start of a new era in gravitational wave physics and astronomy.
The IceCube Neutrino Observatory is located at the South Pole and is designed to observe the cosmos from deep within the ice. At IceCube I studied properties of high-energy neutrinos for realtime searches of their astrophysical sources.
An interesting way to study the multi-messenger and multi-wavelength astrophysical sources is to design and use multi-messenger cyber-infrastructures to do realtime searches between different data streams and perform rapid follow-up observations of significant coincidences. One current example of such central hubs is the Astrophysical Multimessenger Observatory Network (AMON). AMON is a project at Penn State which is a single virtual network that links several high-energy astrophysical observatories as well as gravitational wave facilities, enabling near real-time coincidence searches between data from different observatories aiming for multimessenger astrophysical transients and their electromagnetic counterparts and providing alerts to follow-up observatories.
At AMON, I started studies of coincidences between high-energy neutrinos from the IceCube neutrino observatories and gamma-rays from HAWC using the AMON infrastructure. I also lead the X-ray and Optical/UV follow-up efforts of the realtime IceCube high-energy neutrinos using the NASA's Swift satellite.
I am also involved in a new project called Scalable Cyberinfrastructure for Multi-Messenger Astrophysics (SCiMMA). This project is at the developing stages and the first phase is funded by the National Science Foundation.
My PhD thesis was a study on the Galactic magnetic deflections of ultra-high energy cosmic rays. I modeled the random component of the Galactic magnetic field, simulated cosmic rays, and propagated them through the field to measure their deflections. I also used the data of the Pierre Auger Observatory for this study. My dissertation is accessible from here.
S. Countryman, A. Keivani, I. Bartos, et al., Low-Latency Algorithm for Multi-messenger Astrophysics (LLAMA) with Gravitational-Wave and High-Energy Neutrino Candidates, Submitted to Physical Review D, arXiv:1901.05486
A. Keivani, K. Murase, M. Petropoulou, D. B. Fox, et al., A Multimessenger Picture of the Flaring Blazar TXS 0506+056: Implications of High-Energy Neutrino Emission and Cosmic Ray Acceleration, Astrophysical Journal 864, 84 (2018), arXiv:1807.04537
IceCube Collaboration, Fermi LAT, MAGIC, et al., Multimessenger observations of a flaring blazar coincident with high-energy neutrino IceCube-170922A, Science 361, eaat1378 (2018), arXiv:1807.08816
IceCube Collaboration, Neutrino emission from the direction of the blazar TXS 0506+056 prior to the IceCube-170922A alert, Science 361, aat2890 (2018), arXiv:1807.08794
C. F. Turley, D. B. Fox, A. Keivani, et al., A Coincidence Search for Cosmic Neutrino and Gamma-Ray Emitting Sources Using IceCube and Fermi LAT Public Data, Astrophysical Journal (2018), arXiv:1802.08165
IceCube Collaboration, The IceCube Realtime Alert System, Astroparticle Physics 92, 30 (2017), arXiv:1612.06028
IceCube Collaboration, Multiwavelength follow-up of a rare IceCube neutrino multiplet, Astronomy & Astrophysics 607, A115 (2017), arXiv:1702.06131
J. J. DeLaunay, D. B. Fox, K. Murase, P. Mészáros, A. Keivani, et al., Discovery of a Transient Gamma-ray Counterpart to FRB 131104, Astrophysical Journal Letters 832, L1 (2016), arXiv:1611.03139
A. Keivani et al., Magnetic Deflections of Ultra-High Energy Cosmic Rays from Centaurus A, Astroparticle Physics 61, 47 (2015), arXiv:1406.5249