Journal article
Chandra, HST/STIS, NICER, Swift, and TESS Detail the Flare Evolution of the Repeating Nuclear Transient ASASSN -14ko
AV Payne, K Auchettl, BJ Shappee, CS Kochanek, PT Boyd, TWS Holoien, MM Fausnaugh, C Ashall, JT Hinkle, PJ Vallely, KZ Stanek, TA Thompson
Astrophysical Journal | Published : 2023
Abstract
ASASSN-14ko is a nuclear transient at the center of the AGN ESO 253−G003 that undergoes periodic flares. Optical flares were first observed in 2014 by the All-Sky Automated Survey for Supernovae (ASAS-SN) and their peak times are well-modeled with a period of 115.2 − 1.2 + 1.3 days and period derivative of −0.0026 ± 0.0006. Here we present ASAS-SN, Chandra, HST/STIS, NICER, Swift, and TESS data for the flares that occurred on 2020 December, 2021 April, 2021 July, and 2021 November. These four flares represent flares 18-21 of the total number of flares observed by ASAS-SN so far since 2014. The HST/STIS UV spectra evolve from blueshifted broad absorption features to redshifted broad emission ..
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Grants
Awarded by Ohio State University
Funding Acknowledgements
We thank the anonymous referee for their helpful and constructive comments. We thank Rick Pogge for the valuable discussions. We thank Las Cumbres Observatory and its staff for their continued support of ASAS-SN. ASAS-SN is funded in part by the Gordon and Betty Moore Foundation through grants GBMF5490 and GBMF10501 to the Ohio State University, and also funded in part by the Alfred P. Sloan Foundation grant G-2021-14192. A.V.P. acknowledges support from the NASA Graduate Fellowship through grant 80NSSC19K1679. B.J.S., C.S.K., and K.Z.S. are supported by NSF grant AST- 1907570. B.J.S. is also supported by NSF grants AST-1920392, AST-1911074, and AST-1911074. C.S.K. and K.Z.S. are supported by NSF grant AST-181440. Support for T.W.-S.H. was provided by NASA through the NASA Hubble Fellowship grant HST-HF2-51458.001-A awarded by the Space Telescope Science Institute, which is operated by the Association of Universities for Research in Astronomy, Inc., for NASA, under contract NAS5-26555. Parts of this research were supported by the Australian Research Council Centre of Excellence for All Sky Astrophysics in 3 Dimensions (ASTRO 3D), through project number CE170100013. T.A.T. is supported in part by Scialog Scholar grant 24215 from the Research Corporation. J.T.H. is supported by NASA award 80NSSC21K0136. Some of the data presented in this paper were obtained from the Mikulski Archive for Space Telescopes (MAST) at the Space Telescope Science Institute. The specific observations analyzed can be accessed via doi:10.17909/hk87-6g84. STScI is operated by the Association of Universities for Research in Astronomy, Inc., under NASA contract NAS526555. Support to MAST for these data is provided by the NASA Office of Space Science via grant NAG57584 and by other grants and contracts. This paper includes data collected with the TESS mission, obtained from the MAST data archive at the Space Telescope Science Institute (STScI). Funding for the TESS mission is provided by the NASA Explorer Program. STScI is operated by the Association of Universities for Research in Astronomy, Inc., under NASA contract NAS 5-26555. C.S.K., K.Z.S., and D.M.R. TESS research is supported by NASA grant 80NSSC22K0128. Software: astropy (Astropy Collaboration et al. 2018), ftools (Blackburn 1995), HEAsoft (HEASARC 2014), IRAF (Tody 1986, 1993), numpy (Harris et al. 2020), matplotlib (Hunter 2007).