The Fermi-LAT Light Curve Repository: A resource for the time-domain and multi-messenger communities

Abstract

For over 15 years the Fermi Large Area Telescope (Fermi-LAT) has been monitoring the entire high-energy gamma-ray sky, providing the best sampled 0.1 -> 1 TeV photons to this day. As a result, the Fermi-LAT has been serving the time-domain and multi-messenger community as the main source of gamma-ray activity alerts. All of this makes the Fermi-LAT a key instrument towards understanding the underlying physics behind the most extreme objects in the universe. However, generating mission-long LAT light curves can be very computationally expensive. The Fermi-LAT light curve repository (LCR) tackles this issue. The LCR is a public library of gammaray light curves for 1525 Fermi-LAT sources deemed variable in the 4FGL-DR2 catalog. The repository consists of light curves on timescales of days, weeks, and months, generated through a full-likelihood unbinned analysis of the source and surrounding region, providing flux and photon index measurements for each time interval. Hosted at NASA's FSSC, the library provides users with access to this continually updated light curve data, further serving as a resource to the timedomain and multi-messenger communities.

How do nuclear isomers influence the gamma-ray bursts in binary neutron star mergers?

“…It is agreed that their γ-ray emission follows roughly the same pattern, starting with a short, spectrally hard burst, followed by a longer tail of spectrally softer emission, and ending with a long-lasting multi-wavelength afterglow (Li and Paczynski, 1998;Lamb et al, 2022). Despite the detection of over 12,000 GRBs since their discovery, and extensive research on this topic, the jet formation mechanism remains elusive (Burns and Fryer, 2023;Valverde et al, 2023).…”