Browsing by Author "Woo, J."

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    A Multiwavelength Investigation of PSR J2229+6114 and its Pulsar Wind Nebula in the Radio, X-Ray, and Gamma-Ray Bands
    (IOP, 2024-01) Pope, I.; Mori, K.; Abdelmaguid, M.; Gelfand, J. D.; Reynolds, S. P.; Safi-Harb, S.; Hailey, C. J.; An, H.; (NuSTAR Collaboration); Bangale, P.; Batista, P.; Benbow, W.; Buckley, J. H.; Capasso, M.; Christiansen, J. L.; Chromey, A. J.; Falcone, A.; Feng, Q.; Finley, J. P.; Foote, G. M.; Gallagher, G.; Hanlon, W. F.; Hanna, D.; Hervet, O.; Holder, J.; Humensky, T. B.; Jin, W.; Kaaret, P.; Kertzman, M.; Kieda, D.; Kleiner, T. K.; Korzoun, N.; Krennrich, F.; Kumar, S.; Lang, M. J.; Maier, G.; McGrath, C. E.; Mooney, C. L.; Moriarty, P.; Mukherjee, R.; O'Brien, S.; Ong, R. A.; Park, N.; Patel, S. R.; Pfrang, K.; Pohl, M.; Pueschel, E.; Quinn, J.; Ragan, K.; Reynolds, P. T.; Roache, E.; Sadeh, I.; Saha, L.; Sembroski, G. H.; Tak, D.; Tucci, J. V.; Weinstein, A.; Williams, D. A.; Woo, J.; (VERITAS Collaboration); Physics, School of Science
    G106.3+2.7, commonly considered to be a composite supernova remnant (SNR), is characterized by a boomerang-shaped pulsar wind nebula (PWN) and two distinct ("head" and "tail") regions in the radio band. A discovery of very-high-energy gamma-ray emission (Eγ > 100 GeV) followed by the recent detection of ultrahigh-energy gamma-ray emission (Eγ > 100 TeV) from the tail region suggests that G106.3+2.7 is a PeVatron candidate. We present a comprehensive multiwavelength study of the Boomerang PWN (100'' around PSR J2229+6114) using archival radio and Chandra data obtained two decades ago, a new NuSTAR X-ray observation from 2020, and upper limits on gamma-ray fluxes obtained by Fermi-LAT and VERITAS observatories. The NuSTAR observation allowed us to detect a 51.67 ms spin period from the pulsar PSR J2229+6114 and the PWN emission characterized by a power-law model with Γ = 1.52 ± 0.06 up to 20 keV. Contrary to the previous radio study by Kothes et al., we prefer a much lower PWN B-field (B ∼ 3 μG) and larger distance (d ∼ 8 kpc) based on (1) the nonvarying X-ray flux over the last two decades, (2) the energy-dependent X-ray size of the PWN resulting from synchrotron burn-off, and (3) the multiwavelength spectral energy distribution (SED) data. Our SED model suggests that the PWN is currently re-expanding after being compressed by the SNR reverse shock ∼1000 yr ago. In this case, the head region should be formed by GeV–TeV electrons injected earlier by the pulsar propagating into the low-density environment.
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    A VERITAS/Breakthrough Listen Search for Optical Technosignatures
    (IOP, 2023-09) Acharyya, A.; Adams, C. B.; Archer, A.; Bangale, P.; Batista, P.; Benbow, W.; Brill, A.; Capasso, M.; Errando, M.; Falcone, A.; Feng, Q.; Finley, J. P.; Foote, G. M.; Fortson, L.; Furniss, A.; Griffin, S.; Hanlon, W.; Hanna, D.; Hervet, O.; Hinrichs, C. E.; Hoang, J.; Holder, J.; Humensky, T. B.; Jin, W.; Kaaret, P.; Kertzman, M.; Kherlakian, M.; Kieda, D.; Kleiner, T. K.; Korzoun, N.; Kumar, S.; Lang, M. J.; Lundy, M.; Maier, G.; McGrath, C. E.; Millard, M. J.; Miller, H. R.; Millis, J.; Mooney, C. L.; Moriarty, P.; Mukherjee, R.; O'Brien, S.; Ong, R. A.; Pohl, M.; Pueschel, E.; Quinn, J.; Ragan, K.; Reynolds, P. T.; Ribeiro, D.; Roache, E.; Ryan, J. L.; Sadeh, I.; Saha, L.; Santander, M.; Sembroski, G. H.; Shang, R.; Tak, D.; Talluri, A. K.; Tucci, J. V.; Vazquez, N.; Williams, D. A.; Wong, S. L.; Woo, J.; VERITAS Collaboration; DeBoer, D.; Isaacson, H.; de Pater, I.; Price, D. C.; Siemion, A.; Physics, School of Science
    The Breakthrough Listen Initiative is conducting a program using multiple telescopes around the world to search for "technosignatures": artificial transmitters of extraterrestrial origin from beyond our solar system. The Very Energetic Radiation Imaging Telescope Array System (VERITAS) Collaboration joined this program in 2018 and provides the capability to search for one particular technosignature: optical pulses of a few nanoseconds in duration detectable over interstellar distances. We report here on the analysis and results of dedicated VERITAS observations of Breakthrough Listen targets conducted in 2019 and 2020 and of archival VERITAS data collected since 2012. Thirty hours of dedicated observations of 136 targets and 249 archival observations of 140 targets were analyzed and did not reveal any signals consistent with a technosignature. The results are used to place limits on the fraction of stars hosting transmitting civilizations. We also discuss the minimum pulse sensitivity of our observations and present VERITAS observations of CALIOP: a space-based pulsed laser on board the Cloud-Aerosol Lidar and Infrared Pathfinder Satellite Observations. The detection of these pulses with VERITAS, using the analysis techniques developed for our technosignature search, allows a test of our analysis efficiency and serves as an important proof of principle.