English

Simultaneous Multiwavelength Flare Observations of EV Lacertae

Solar and Stellar Astrophysics 2021-11-24 v1

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 5 different observatories: NASA's Transiting Exoplanet Survey Satellite (TESS), NASA's Neil Gehrels Swift Observatory (\textit{Swift}), NASA's Neutron Interior Composition Explorer (NICER), the University of Hawaii 2.2-m telescope (UH88) and the Las Cumbres Observatory Global Telescope (LCOGT) Network. During the \sim25 days of TESS observations, we acquired three simultaneous UV/X-ray observations using \textit{Swift} that total \sim18 ks, 21 simultaneous epochs totaling \sim98 ks of X-ray data using NICER, one observation (\sim 3 hours) with UH88, and one observation (\sim 3 hours) with LCOGT. We identified 56 flares in the TESS light curve with estimated energies in the range log ETE_{\rm T} (erg) = (30.5 - 33.2), nine flares in the \textit{Swift} UVM2 light curve with estimated energies in the range log EUVE_{UV} (erg) = (29.3 - 31.1), 14 flares in the NICER light curve with estimated minimum energies in the range log ENE_{N} (erg) = (30.5 - 32.3), and 1 flare in the LCOGT light curve with log ELE_{L} (erg) = 31.6. We find that the flare frequency distributions (FFDs) of TESS and NICER flares have comparable slopes, βT\beta_{T} = -0.67±\pm0.09 and βN\beta_{N} = -0.65±\pm0.19, and the FFD of UVOT flares has a shallower slope (βU\beta_{U} = -0.38±\pm0.13). 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.

Keywords

Cite

@article{arxiv.2108.04753,
  title  = {Simultaneous Multiwavelength Flare Observations of EV Lacertae},
  author = {Rishi R. Paudel and Thomas Barclay and Joshua E. Schlieder and Elisa V. Quintana and Emily A. Gilbert and Laura D. Vega and Allison Youngblood and Michele Silverstein and Rachel A. Osten and Michael A. Tucker and Daniel Huber and Aaron Do and Kenji Hamaguchi and D. J. Mullan and John E. Gizis and Teresa A. Monsue and Knicole D. Colón and Patricia T. Boyd and James R. A. Davenport and Lucianne Walkowicz},
  journal= {arXiv preprint arXiv:2108.04753},
  year   = {2021}
}

Comments

28 pages, 16 Figures, Accepted for publication in the Astrophysical Journal,

R2 v1 2026-06-24T04:59:41.669Z