Gamma-Ray and X-Ray Observations of the Periodic-Repeater FRB 180916 During Active Phases. (arXiv:2004.03676v1 [astro-ph.HE])
<a href="http://arxiv.org/find/astro-ph/1/au:+Tavani_M/0/1/0/all/0/1">M. Tavani</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Verrecchia_F/0/1/0/all/0/1">F. Verrecchia</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Casentini_C/0/1/0/all/0/1">C. Casentini</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Perri_M/0/1/0/all/0/1">M. Perri</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Ursi_A/0/1/0/all/0/1">A. Ursi</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Pacciani_L/0/1/0/all/0/1">L. Pacciani</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Pittori_C/0/1/0/all/0/1">C. Pittori</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Bulgarelli_A/0/1/0/all/0/1">A. Bulgarelli</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Piano_G/0/1/0/all/0/1">G. Piano</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Pilia_M/0/1/0/all/0/1">M. Pilia</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Bernardi_G/0/1/0/all/0/1">G. Bernardi</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Addis_A/0/1/0/all/0/1">A. Addis</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Antonelli_L/0/1/0/all/0/1">L.A. Antonelli</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Argan_A/0/1/0/all/0/1">A. Argan</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Baroncelli_L/0/1/0/all/0/1">L. Baroncelli</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Caraveo_P/0/1/0/all/0/1">P. Caraveo</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Cattaneo_P/0/1/0/all/0/1">P.W. Cattaneo</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Chen_A/0/1/0/all/0/1">A. Chen</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Costa_E/0/1/0/all/0/1">E. Costa</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Persio_G/0/1/0/all/0/1">G. Di Persio</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Donnarumma_I/0/1/0/all/0/1">I. Donnarumma</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Evangelista_Y/0/1/0/all/0/1">Y. Evangelista</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Feroci_M/0/1/0/all/0/1">M. Feroci</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Ferrari_A/0/1/0/all/0/1">A. Ferrari</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Fioretti_V/0/1/0/all/0/1">V. Fioretti</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Lazzarotto_F/0/1/0/all/0/1">F. Lazzarotto</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Longo_F/0/1/0/all/0/1">F. Longo</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Morselli_A/0/1/0/all/0/1">A. Morselli</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Paoletti_F/0/1/0/all/0/1">F. Paoletti</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Parmiggiani_N/0/1/0/all/0/1">N. Parmiggiani</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Trois_A/0/1/0/all/0/1">A. Trois</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Vercellone_S/0/1/0/all/0/1">S. Vercellone</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Naldi_G/0/1/0/all/0/1">G. Naldi</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Pupillo_G/0/1/0/all/0/1">G. Pupillo</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Bianchi_G/0/1/0/all/0/1">G. Bianchi</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Puccetti_S/0/1/0/all/0/1">S. Puccetti</a>

FRB 180916 is a most intriguing source at 150 Mpc distance capable of
producing repeating fast radio bursts with a periodic 16.35 day temporal
pattern. We report on the X-ray and $gamma$-ray observations of FRB 180916
obtained by AGILE and Swift. We focused on the recurrent 5-day time intervals
of active radio bursting and present results obtained on Feb. 3 – 8; Feb. 25;
Mar. 5 – 10; Mar. 22 – 28, 2020 during a multiwavelength campaign involving
high-energy and radio observations. We also searched for temporal coincidences
at millisecond timescales between all known radio bursts of FRB 180916 and
X-ray and MeV events detectable by AGILE. We do not detect any simultaneous
event or any extended X-ray and $gamma$-ray emission on timescales of
hours/days/weeks. Our cumulative X-ray (0.3-10 keV) flux upper limit of $5
times,10^{-14} rm , erg , cm^{-2} s^{-1}$ (obtained during 5-day active
intervals) translates into an isotropic luminosity upper limit of $L_{X,UL}
sim 1.5 times, 10^{41} rm erg , s^{-1}$. Observations above 100 MeV over a
many-year timescale provide an average luminosity upper limit one order of
magnitude larger. These results provide the so-far most stringent limits on
high-energy emission from FRB 180916 and constrain the dissipation of magnetic
energy from a magnetar-like source of radius $R_m$, internal magnetic field
$B_m$ and dissipation timescale $tau_d$ to satisfy the relation $R_{m,6}^3
B_{m,16}^2 tau_{d,8}^{-1} lesssim 1$, where $R_{m,6}$ is $R_m$ in units of
$10^6$ cm, $B_{m,16}$ is $B_m$ in units of $10^{16}$ G, and $tau_{d,8}$ in
units of $10^8$ s.

FRB 180916 is a most intriguing source at 150 Mpc distance capable of
producing repeating fast radio bursts with a periodic 16.35 day temporal
pattern. We report on the X-ray and $gamma$-ray observations of FRB 180916
obtained by AGILE and Swift. We focused on the recurrent 5-day time intervals
of active radio bursting and present results obtained on Feb. 3 – 8; Feb. 25;
Mar. 5 – 10; Mar. 22 – 28, 2020 during a multiwavelength campaign involving
high-energy and radio observations. We also searched for temporal coincidences
at millisecond timescales between all known radio bursts of FRB 180916 and
X-ray and MeV events detectable by AGILE. We do not detect any simultaneous
event or any extended X-ray and $gamma$-ray emission on timescales of
hours/days/weeks. Our cumulative X-ray (0.3-10 keV) flux upper limit of $5
times,10^{-14} rm , erg , cm^{-2} s^{-1}$ (obtained during 5-day active
intervals) translates into an isotropic luminosity upper limit of $L_{X,UL}
sim 1.5 times, 10^{41} rm erg , s^{-1}$. Observations above 100 MeV over a
many-year timescale provide an average luminosity upper limit one order of
magnitude larger. These results provide the so-far most stringent limits on
high-energy emission from FRB 180916 and constrain the dissipation of magnetic
energy from a magnetar-like source of radius $R_m$, internal magnetic field
$B_m$ and dissipation timescale $tau_d$ to satisfy the relation $R_{m,6}^3
B_{m,16}^2 tau_{d,8}^{-1} lesssim 1$, where $R_{m,6}$ is $R_m$ in units of
$10^6$ cm, $B_{m,16}$ is $B_m$ in units of $10^{16}$ G, and $tau_{d,8}$ in
units of $10^8$ s.

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