J. S. Brown

ASASSN-14ae: a tidal disruption event at 200 Mpc

ASASSN-14ae is a candidate tidal disruption event (TDE) found at the centre of SDSS J110840.11+340552.2 (d ≃ 200 Mpc) by the All-Sky Automated Survey for Supernovae (ASAS-SN). We present ground-based and Swift follow-up photometric and spectroscopic observations of the source, finding that the transient had a peak luminosity of L ≃ 8 × 1043 erg s−1 and a total integrated energy of E ≃ 1.7 × 1050 erg radiated over the ∼5 months of observations presented. The blackbody temperature of the transient remains roughly constant at T ∼ 20 000 K while the luminosity declines by nearly 1.5 orders of magnitude during this time, a drop that is most consistent with an exponential, L ∝ e-t/t 0 with t0 ≃ 39 d. The source has broad Balmer lines in emission at all epochs as well as a broad He ii feature emerging in later epochs. We compare the colour and spectral evolution to both supernovae and normal AGN to show that ASASSN-14ae does not resemble either type of object and conclude that a TDE is the most likely explanation for our observations. At z = 0.0436, ASASSN-14ae is the lowest-redshift TDE candidate discovered at optical/UV wavelengths to date, and we estimate that ASAS-SN may discover 0.1–3 of these events every year in the future.

ASASSN-15lh: A highly super-luminous supernova

The most luminous supernova to date Supernovae are exploding stars at the end of their lives, providing an input of heavy elements and energy into galaxies. Some types have near-identical peak brightness, but in recent years a new class of superluminous supernovae has been found. Dong et al.y report the discovery of ASASSN-15lh (SN 2015L), the most luminous supernova yet found by some margin. It appears to originate in a large quiescent galaxy, in contrast to most super-luminous supernovae, which typically come from star-forming dwarf galaxies. The discovery will provide constraints on models of superluminous supernovae and how they affect their host galaxies. Science, this issue p. 257 The most luminous supernova yet found was glimpsed in an unusual host galaxy. We report the discovery of ASASSN-15lh (SN 2015L), which we interpret as the most luminous supernova yet found. At redshift z = 0.2326, ASASSN-15lh reached an absolute magnitude of Mu,AB = –23.5 ± 0.1 and bolometric luminosity Lbol = (2.2 ± 0.2) × 1045 ergs s–1, which is more than twice as luminous as any previously known supernova. It has several major features characteristic of the hydrogen-poor super-luminous supernovae (SLSNe-I), whose energy sources and progenitors are currently poorly understood. In contrast to most previously known SLSNe-I that reside in star-forming dwarf galaxies, ASASSN-15lh appears to be hosted by a luminous galaxy (MK ≈ –25.5) with little star formation. In the 4 months since first detection, ASASSN-15lh radiated (1.1 ± 0.2) × 1052 ergs, challenging the magnetar model for its engine.

ASASSN-15oi: a rapidly evolving, luminous tidal disruption event at 216 Mpc

We present ground-based and Swift photometric and spectroscopic observations of the tidal disruption event (TDE) ASASSN-15oi, discovered at the center of 2MASX J20390918-3045201 (

THE BLACK HOLE MASS OF NGC 4151. II. STELLAR DYNAMICAL MEASUREMENT FROM NEAR-INFRARED INTEGRAL FIELD SPECTROSCOPY

d\simeq216

A Recalibration of Strong Line Oxygen Abundance Diagnostics via the Direct Method and Implications for the High Redshift Universe

Mpc) by the All-Sky Automated Survey for SuperNovae (ASAS-SN). The source peaked at a bolometric luminosity of

Hello darkness my old friend: the fading of the nearby TDE ASASSN-14ae

L\simeq1.9\times10^{44}

The ASAS-SN bright supernova catalogue – I. 2013–2014

ergs s

The ASAS-SN Bright Supernova Catalog – II. 2015

^{-1}

Supernova progenitors, their variability and the Type IIP Supernova ASASSN-16fq in M66

and radiated a total energy of

The ultraviolet spectroscopic evolution of the low-luminosity tidal disruption event iPTF16fnl

E\simeq5.0\times10^{50}