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Research output: Contribution to Journal/Magazine › Journal article › peer-review
Research output: Contribution to Journal/Magazine › Journal article › peer-review
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TY - JOUR
T1 - Swift/UVOT discovery of Swift J221951−484240: a UV luminous ambiguous nuclear transient
AU - Oates, S R
AU - Kuin, N P M
AU - Nicholl, M
AU - Marshall, F
AU - Ridley, E
AU - Boutsia, K
AU - Breeveld, A A
AU - Buckley, D A H
AU - Cenko, S B
AU - De Pasquale, M
AU - Edwards, P G
AU - Gromadzki, M
AU - Gupta, R
AU - Laha, S
AU - Morrell, N
AU - Orio, M
AU - Pandey, S B
AU - Page, M J
AU - Page, K L
AU - Parsotan, T
AU - Rau, A
AU - Schady, P
AU - Stevens, J
AU - Brown, P J
AU - Evans, P A
AU - Gronwall, C
AU - Kennea, J A
AU - Klingler, N J
AU - Siegel, M H
AU - Tohuvavohu, A
AU - Ambrosi, E
AU - Barthelmy, S D
AU - Beardmore, A P
AU - Bernardini, M G
AU - Bonnerot, C
AU - Campana, S
AU - Caputo, R
AU - Ciroi, S
AU - Cusumano, G
AU - D’Aì, A
AU - D’Avanzo, P
AU - D’Elia, V
AU - Giommi, P
AU - Hartmann, D H
AU - Krimm, H A
AU - Malesani, D B
AU - Melandri, A
AU - Nousek, J A
AU - O’Brien, P T
AU - Osborne, J P
AU - Pagani, C
AU - Palmer, D M
AU - Perri, M
AU - Racusin, J L
AU - Sakamoto, T
AU - Sbarufatti, B
AU - Schlieder, J E
AU - Tagliaferri, G
AU - Troja, E
AU - Xu, D
PY - 2024/5/31
Y1 - 2024/5/31
N2 - We report the discovery of Swift J221951−484240 (hereafter: J221951), a luminous slow-evolving blue transient that was detected by the Neil Gehrels Swift Observatory Ultraviolet/Optical Telescope (Swift/UVOT) during the follow-up of gravitational wave alert S190930t, to which it is unrelated. Swift/UVOT photometry shows the UV spectral energy distribution of the transient to be well modelled by a slowly shrinking blackbody with an approximately constant temperature of T ∼ 2.5 × 104 K. At a redshift z = 0.5205, J221951 had a peak absolute magnitude of Mu,AB = −23 mag, peak bolometric luminosity $L_{max}=1.1\times 10^{45}~{\rm erg\, s}^{-1}$ and a total radiated energy of E > 2.6 × 1052 erg. The archival Wide-field Infrared Survey Explorer IR photometry shows a slow rise prior to a peak near the discovery date. Spectroscopic UV observations display broad absorption lines in N v and O vi, pointing towards an outflow at coronal temperatures. The lack of emission in the higher H α lines, N i and other neutral lines is consistent with a viewing angle close to the plane of the accretion or debris disc. The origin of J221951 cannot be determined with certainty but has properties consistent with a tidal disruption event and the turn-on of an active galactic nucleus.
AB - We report the discovery of Swift J221951−484240 (hereafter: J221951), a luminous slow-evolving blue transient that was detected by the Neil Gehrels Swift Observatory Ultraviolet/Optical Telescope (Swift/UVOT) during the follow-up of gravitational wave alert S190930t, to which it is unrelated. Swift/UVOT photometry shows the UV spectral energy distribution of the transient to be well modelled by a slowly shrinking blackbody with an approximately constant temperature of T ∼ 2.5 × 104 K. At a redshift z = 0.5205, J221951 had a peak absolute magnitude of Mu,AB = −23 mag, peak bolometric luminosity $L_{max}=1.1\times 10^{45}~{\rm erg\, s}^{-1}$ and a total radiated energy of E > 2.6 × 1052 erg. The archival Wide-field Infrared Survey Explorer IR photometry shows a slow rise prior to a peak near the discovery date. Spectroscopic UV observations display broad absorption lines in N v and O vi, pointing towards an outflow at coronal temperatures. The lack of emission in the higher H α lines, N i and other neutral lines is consistent with a viewing angle close to the plane of the accretion or debris disc. The origin of J221951 cannot be determined with certainty but has properties consistent with a tidal disruption event and the turn-on of an active galactic nucleus.
U2 - 10.1093/mnras/stae795
DO - 10.1093/mnras/stae795
M3 - Journal article
VL - 530
SP - 1688
EP - 1710
JO - Monthly Notices of the Royal Astronomical Society
JF - Monthly Notices of the Royal Astronomical Society
SN - 0035-8711
IS - 2
ER -