TY - JOUR
T1 - IPTF16fnl
T2 - A Faint and Fast Tidal Disruption Event in an E+A Galaxy
AU - Blagorodnova, N.
AU - Gezari, S.
AU - Hung, T.
AU - Kulkarni, S. R.
AU - Cenko, S. B.
AU - Pasham, D. R.
AU - Yan, L.
AU - Arcavi, I.
AU - Ben-Ami, S.
AU - Bue, B. D.
AU - Cantwell, T.
AU - Cao, Y.
AU - Castro-Tirado, A. J.
AU - Fender, R.
AU - Fremling, C.
AU - Gal-Yam, A.
AU - Ho, A. Y.Q.
AU - Horesh, A.
AU - Hosseinzadeh, G.
AU - Kasliwal, M. M.
AU - Kong, A. K.H.
AU - Laher, R. R.
AU - Leloudas, G.
AU - Lunnan, R.
AU - Masci, F. J.
AU - Mooley, K.
AU - Neill, J. D.
AU - Nugent, P.
AU - Powell, M.
AU - Valeev, A. F.
AU - Vreeswijk, P. M.
AU - Walters, R.
AU - Wozniak, P.
N1 - Publisher Copyright:
© 2017. The American Astronomical Society. All rights reserved.
PY - 2017/7/20
Y1 - 2017/7/20
N2 - We present ground-based and Swift observations of iPTF16fnl, a likely tidal disruption event (TDE) discovered by the intermediate Palomar Transient Factory (iPTF) survey at 66.6 Mpc. The light curve of the object peaked at an absolute mag Mg = -17.2. The maximum bolometric luminosity (from optical and UV) was Lp ≃ (1.0 ± 0.15) × 1043erg s-1, an order of magnitude fainter than any other optical TDE discovered so far. The luminosity in the first 60 days is consistent with an exponential decay, with L ∝ e-(t-t0)/τ, where t0 = 57631.0 (MJD) and τ ≃ 15 days. The X-ray shows a marginal detection at LX = 2.41.9 -1.1 × 1039 erg s-1 (Swift X-ray Telescope). No radio counterpart was detected down to 3σ, providing upper limits for monochromatic radio luminosities of νLν < 1.7 × 1036 erg s-1 and νLν < 2.3 × 1037 erg s-1 (Very Large Array, 6.1 and 22 GHz). The blackbody temperature, obtained from combined Swift UV and optical photometry, shows a constant value of 19,000 K. The transient spectrum at peak is characterized by broad He ii and Hα emission lines, with FWHMs of about 14,000 km s-1 and 10,000 km s-1, respectively. He i lines are also detected at λλ 5875 and 6678. The spectrum of the host is dominated by strong Balmer absorption lines, which are consistent with a post-starburst (E+A) galaxy with an age of ∼650 Myr and solar metallicity. The characteristics of iPTF16fnl make it an outlier on both luminosity and decay timescales, as compared to other optically selected TDEs. The discovery of such a faint optical event suggests a higher rate of tidal disruptions, as low-luminosity events may have gone unnoticed in previous searches.
AB - We present ground-based and Swift observations of iPTF16fnl, a likely tidal disruption event (TDE) discovered by the intermediate Palomar Transient Factory (iPTF) survey at 66.6 Mpc. The light curve of the object peaked at an absolute mag Mg = -17.2. The maximum bolometric luminosity (from optical and UV) was Lp ≃ (1.0 ± 0.15) × 1043erg s-1, an order of magnitude fainter than any other optical TDE discovered so far. The luminosity in the first 60 days is consistent with an exponential decay, with L ∝ e-(t-t0)/τ, where t0 = 57631.0 (MJD) and τ ≃ 15 days. The X-ray shows a marginal detection at LX = 2.41.9 -1.1 × 1039 erg s-1 (Swift X-ray Telescope). No radio counterpart was detected down to 3σ, providing upper limits for monochromatic radio luminosities of νLν < 1.7 × 1036 erg s-1 and νLν < 2.3 × 1037 erg s-1 (Very Large Array, 6.1 and 22 GHz). The blackbody temperature, obtained from combined Swift UV and optical photometry, shows a constant value of 19,000 K. The transient spectrum at peak is characterized by broad He ii and Hα emission lines, with FWHMs of about 14,000 km s-1 and 10,000 km s-1, respectively. He i lines are also detected at λλ 5875 and 6678. The spectrum of the host is dominated by strong Balmer absorption lines, which are consistent with a post-starburst (E+A) galaxy with an age of ∼650 Myr and solar metallicity. The characteristics of iPTF16fnl make it an outlier on both luminosity and decay timescales, as compared to other optically selected TDEs. The discovery of such a faint optical event suggests a higher rate of tidal disruptions, as low-luminosity events may have gone unnoticed in previous searches.
KW - accretion, accretion disks
KW - black hole physics
KW - galaxies: nuclei
KW - stars: individual (iPTF16fnl)
UR - http://www.scopus.com/inward/record.url?scp=85026406715&partnerID=8YFLogxK
U2 - 10.3847/1538-4357/aa7579
DO - 10.3847/1538-4357/aa7579
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AN - SCOPUS:85026406715
SN - 0004-637X
VL - 844
JO - Astrophysical Journal
JF - Astrophysical Journal
IS - 1
M1 - 46
ER -