Photometry & spectroscopy follow-up of ASASSN-20hx

DOI

We present observations of ASASSN-20hx, a nearby ambiguous nuclear transient (ANT) discovered in NGC 6297 by the All-Sky Automated Survey for Supernovae (ASAS-SN). We observed ASASSN-20hx from -30 to 275 days relative to the peak UV/optical emission using high-cadence, multiwavelength spectroscopy and photometry. From Transiting Exoplanet Survey Satellite data, we determine that the ANT began to brighten on 2020 June 22.8 with a linear rise in flux for at least the first week. ASASSN-20hx peaked in the UV/optical 30 days later on 2020 July 22.8 (MJD=59052.8) at a bolometric luminosity of L=(3.15+/-0.04)x10^43^erg/s. The subsequent decline is slower than any TDE observed to date and consistent with many other ANTs. Compared to an archival X-ray detection, the X-ray luminosity of ASASSN-20hx increased by an order of magnitude to Lx~1.5x10^42^erg/s and then slowly declined over time. The X-ray emission is well fit by a power law with a photon index of {Gamma}~2.3-2.6. Both the optical and near-infrared spectra of ASASSN-20hx lack emission lines, unusual for any known class of nuclear transient. While ASASSN-20hx has some characteristics seen in both tidal disruption events and active galactic nuclei, it cannot be definitively classified with current data.

Identifier
DOI http://doi.org/10.26093/cds/vizier.19300012
Source https://dc.g-vo.org/rr/q/lp/custom/CDS.VizieR/J/ApJ/930/12
Related Identifier https://cdsarc.cds.unistra.fr/viz-bin/cat/J/ApJ/930/12
Related Identifier http://vizier.cds.unistra.fr/viz-bin/VizieR-2?-source=J/ApJ/930/12
Metadata Access http://dc.g-vo.org/rr/q/pmh/pubreg.xml?verb=GetRecord&metadataPrefix=oai_b2find&identifier=ivo://CDS.VizieR/J/ApJ/930/12
Provenance
Creator Hinkle J.T.; Holoien T.W.-S.; Shappee B.J.; Neustadt J.M.M.; Auchettl K.,Vallely P.J.; Shahbandeh M.; Kluge M.; Kochanek C.S.; Stanek K.Z.,Huber M.E.; Post R.S.; Bersier D.; Ashall C.; Tucker M.A.; Williams J.P.,de Jaeger T.; Do A.; Fausnaugh M.; Gruen D.; Hopp U.; Myles J.,Obermeier C.; Payne A.V.; Thompson T.A.
Publisher CDS
Publication Year 2024
Rights https://cds.unistra.fr/vizier-org/licences_vizier.html
OpenAccess true
Contact CDS support team <cds-question(at)unistra.fr>
Representation
Resource Type Dataset; AstroObjects
Discipline Astrophysics and Astronomy; Cosmology; High Energy Astrophysics; Interdisciplinary Astronomy; Natural Sciences; Observational Astronomy; Physics