J/MNRAS/463/3813 ASASSN-15oi UBVI M2W1W2 light curves (Holoien+, 2016)
ASASSN-15oi: a rapidly evolving, luminous tidal disruption event at 216 Mpc.
Holoien T.W.-S., Kochanek C.S., Prieto J.L., Grupe D., Chen P.,
Godoy-Rivera D., Stanek K.Z., Shappee B.J., Dong S., Brown J.S., Basu U.,
Beacom J.F., Bersier D., Brimacombe J., Carlson E.K., Falco E.,
Johnston E., Madore B.F., Pojmanski G., Seibert M.
<Mon. Not. R. Astron. Soc., 463, 3813-3828 (2016)>
=2016MNRAS.463.3813H 2016MNRAS.463.3813H (SIMBAD/NED BibCode)
ADC_Keywords: Supernovae ; Photometry, UBVRI
Keywords: accretion, accretion discs - black hole physics - galaxies - nuclei
Abstract:
We present ground-based and Swift photometric and spectroscopic
observations of the tidal disruption event (TDE) ASASSN-15oi,
discovered at the centre of 2MASX J20390918-3045201 (d~=216Mpc) by the
All-Sky Automated Survey for SuperNovae. The source peaked at a
bolometric luminosity of L~=1.3x1044erg/s and radiated a total
energy of E~=6.6x1050 erg over the first ∼3.5 months of
observations. The early optical/UV emission of the source can be fit
by a blackbody with temperature increasing from T~=2x104K to
T~=4x104K while the luminosity declines from L~=1.3x1044erg/s to
L~=2.3x1043erg/s, requiring the photosphere to be shrinking rapidly.
The optical/UV luminosity decline during this period is most
consistent with an exponential decline, L∝e-(t-t0)/tau_^,
with τ~=46.5d for t0~=57241.6 (MJD), while a power-law decline
of L∝(t-t0)-α with t0~=57212.3 and α=1.62
provides a moderately worse fit. ASASSN-15oi also exhibits roughly
constant soft X-ray emission that is significantly weaker than the
optical/UV emission. Spectra of the source show broad helium emission
lines and strong blue continuum emission in early epochs, although
these features fade rapidly and are not present ∼3 months after
discovery. The early spectroscopic features and colour evolution of
ASASSN-15oi are consistent with a TDE, but the rapid spectral
evolution is unique among optically selected TDEs.
Description:
After the transient was classified as a TDE, we obtained a series of
26 Swift XRT and UVOT target-of-opportunity (ToO) observations. The
UVOT observations were obtained in six filters: V (5468Å), B
(4392Å), U (3465Å), UVW1 (2600Å), UVM2 (2246Å), and UVW2
(1928Å)
We also obtained BVI images with the Las Cumbres Observatory Global
Telescope Network (LCOGT; Brown et al. 2013) 1-m telescopes at Siding
Spring, South African Astronomical, and Cerro Tololo Inter-America
Observatories.
Objects:
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RA (2000) DE Designation(s)
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20 39 09.10 -30 45 20.7 ASASSN-15oi = ASASSN -15oi
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File Summary:
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FileName Lrecl Records Explanations
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ReadMe 80 . This file
tablea1.dat 30 241 Photometric data of ASASSN-15oi
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Byte-by-byte Description of file: tablea1.dat
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Bytes Format Units Label Explanations
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1- 9 F9.3 d MJD Observation date (MJD)
11- 15 F5.2 mag mag Magnitude in Filter (Vega) (1)
17- 21 F5.3 mag e_mag rms uncertainty on mag (Vega) (1)
23- 24 A2 --- Filt [UBVI M2 W1 W2] Filter
26- 30 A5 --- Tel [LCOGT Swift] Telescope
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Note (1): Data are not corrected for Galactic extinction.
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History:
From electronic version of the journal
(End) Patricia Vannier [CDS] 14-May-2018