Long-term follow-up observations of extreme coronal line emitting galaxies
Abstract
We present new spectroscopic and photometric follow-up observations of the known sample of extreme coronal line emitting galaxies (ECLEs) identified in the Sloan Digital Sky Survey (SDSS). With these new data, observations of the ECLE sample now span a period of two decades following their initial SDSS detections. We confirm the nonrecurrence of the iron coronal line signatures in five of the seven objects, further supporting their identification as the transient light echoes of tidal disruption events (TDEs). Photometric observations of these objects in optical bands show little overall evolution. In contrast, mid-infrared (MIR) observations show ongoing long-term declines. The remaining two objects had been classified as active galactic nuclei (AGN) with unusually strong coronal lines rather than being TDE related, given the persistence of the coronal lines in earlier follow-up spectra. We confirm this classification, with our spectra continuing to show the presence of strong, unchanged coronal-line features and AGN-like MIR colours and behaviour. We have constructed spectral templates of both subtypes of ECLE to aid in distinguishing the likely origin of newly discovered ECLEs. We highlight the need for higher cadence, and more rapid, follow-up observations of such objects to better constrain their properties and evolution. We also discuss the relationships between ECLEs, TDEs, and other identified transients having significant MIR variability.
Keywords
Cite
@article{arxiv.2307.03182,
title = {Long-term follow-up observations of extreme coronal line emitting galaxies},
author = {Peter Clark and Or Graur and Joseph Callow and Jessica Aguilar and Steven Ahlen and Joseph P. Anderson and Edo Berger and Thomas Brink and David Brooks and Ting-Wan Chen and Todd Claybaugh and Axel de la Macorra and Peter Doel and Alexei Filippenko and Jamie Forero-Romero and Sebastian Gomez and Mariusz Gromadzki and Klaus Honscheid and Cosimo Inserra and Theodore Kisner and Martin Landriau and Lydia Makrygianni and Marc Manera and Aaron Meisner and Ramon Miquel and John Moustakas and Tomás E. Müller-Bravo and Matt Nicholl and Jundan Nie and Francesca Onori and Antonella Palmese and Claire Poppett and Thomas Reynolds and Mehdi Rezaie and Graziano Rossi and Eusebio Sanchez and Michael Schubnell and Gregory Tarlé and Benjamin A. Weaver and Thomas Wevers and David R. Young and WeiKang Zheng and Zhimin Zhou},
journal= {arXiv preprint arXiv:2307.03182},
year = {2024}
}
Comments
This is a pre-copyedited, author-produced PDF of an article accepted for publication in Monthly Notices of the Royal Astronomical Society following peer review. Note the corrected caption of Figure 1 continued, which in this version correctly refers to 'SDSS J124' rather than the erroneous 'SDSS J1341' in the published version. 29 Pages, 14 Figures