Simultaneous Multiwavelength Flare Observations of EV Lacertae

Date

2021-11-16

Department

Program

Citation of Original Publication

Paudel, Rishi R. Simultaneous Multiwavelength Flare Observations of EV Lacertae. The Astrophysical Journal 922 (Nov. 16, 2021), no. 1. https://doi.org/10.3847/1538-4357/ac1946.

Rights

This work was written as part of one of the author's official duties as an Employee of the United States Government and is therefore a work of the United States Government. In accordance with 17 U.S.C. 105, no copyright protection is available for such works under U.S. Law.
Public Domain Mark 1.0

Subjects

Abstract

We present the first results of our ongoing project conducting simultaneous multiwavelength observations of flares on nearby active M dwarfs. We acquired data of the nearby dM3.5e star EV Lac using five different observatories: NASA's Transiting Exoplanet Survey Satellite (TESS), NASA's Neil Gehrels Swift Observatory (Swift), NASA's Neutron Interior Composition Explorer (NICER), the University of Hawaii 2.2-meter telescope (UH88), and the Las Cumbres Observatory Global Telescope (LCOGT) Network. During the ∼25 days of TESS observations, we acquired three simultaneous UV/X-ray observations using Swift that total ∼18 ks, 21 simultaneous epochs totaling ∼98 ks of X-ray data using NICER, one observation (∼3 hr) with UH88, and one observation (∼3 hr) with LCOGT. We identified 56 flares in the TESS light curve with estimated energies in the range log ET (erg) = (30.5–33.2), nine flares in the Swift UVM2 light curve with estimated energies in the range log EUV (erg) = (29.3–31.1), 14 flares in the NICER light curve with estimated minimum energies in the range log EN (erg) = (30.5–32.3), and 1 flare in the LCOGT light curve with log EL (erg) = 31.6. We find that the flare frequency distributions (FFDs) of TESS and NICER flares have comparable slopes, βᴛ = −0.67 ± 0.09 and βᶰ = − 0.65 ± 0.19, and the FFD of UVOT flares has a shallower slope (βᴜ = −0.38 ± 0.13). Furthermore, we do not find conclusive evidence for either the first ionization potential (FIP) or the inverse FIP effect during coronal flares on EV Lac.