Tel Aviv University the Energetic OGLE14-073 - SN 1987A on Steroids

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Extreme Transients

Iair (“ya-eer”) Arcavi Tel Aviv University The Energetic OGLE14-073 - SN 1987A on Steroids

Terreran et al. 2017 OGLE14-073 - SN 1987A on Steroids

1/2 1/2 1/2 M v  tpeak 2.7d 2 2 1 ⇡ 10 M 0.1c 1 cm g ✓ ◆ ⇣ ⌘ ✓ ◆

Terreran et al. 2017 The Slowly Evolving iPTF14hls - Objectively the BEST Supernova Ever At least 5 peaks

Last non-det is 140d before discovery Arcavi et al. (2017) SN 1999em (28d)

iPTF14hls (137d) SN 1999em iPTF14hls (typical IIP) Leonard et al. (2002) Leonard et al. (2017) Arcavi How is the Velocity Gradient Constant in Time?

12,000 Central Engine 14hls Fe II 5169Å Pre-Eruption (day <-3500) 99em Hα 10,000 14hls Hα 99em Hβ 14hls Hβ ) 99em Fe II 5169Å 1 - iPTF14hls s

m 8,000 k (

Hα y t i c o l 6,000 e v Hβ n o i s

n 4,000 a

p Fe x E 2,000 SN 1999em 0 0 100 200 300 400 500 600 Time since discovery (rest-frame days) Arcavi et al. (2017) Arcavi Evidence for a Historic Eruption

1954 1993

Arcavi et al. (2017) “Drop” in the Light Curve After 1000 Days

Arcavi+17 This work 16 -20

17 -19

18 -18

19 -17

20 -16 Apparent magnitude

21 -15 Absolute r/R-band magnitude

i-0.8 P48 r/R P60-GRBCam 22 V+0.2 P60-SEDM -14 g+0.8 LCO-1m B+1.7 LCO-2m NOT TNG 23 HST -13

24 -12 S SSSS SS

0 200 400 600 800 1000 1200 Rest-frame days since discovery Sollerman et al. 2019 Extreme Ni-Mass SN II: SN 2018hmx

Bracha et al. In prep. SN 2018hmx: An Extreme Type II SN Extreme Ni-Mass SN II: SN 2018hmx with High Nickel Mass

Shahar Bracha1, Iair Arcavi1, Daichi Hiramatsu2, 3, Jamie Burke2, 3, Jozsef Vinko4, 5, Stephen Smartt6, D. Andrew Howell2, 3, J. Craig Wheeler5, on behalf of the ATLAS and GSP Collaborations

1 Tel Aviv University, 2 Las Cumbres Observatory, 3 University of California, Santa Barbara, [email protected] 4 Konkoly Observatory, Budapest, 5 University of Texas Austin, 6 Queen's University Belfast [email protected]

Discovered by ATLAS on 2018-10-17 (Tonry et al. 2018, TNS High luminosity, but slow decline Transient Report 1615) and classified by ZTF as a Type II SN at z=0.038 (Fremling et al. 2018, TNS Classification Report 1765) Distance modulus= 36.01 (NASA/IPAC Extragalactic Database) Luminous Type II SN

27.509 cm

Vmax = -19 Comparison sample from Valenti et al. 2016, MNRAS, 459, 3939 and to KSP-SN-2016kf from Afsariardchi et al. 2019, ApJ 881:22. Very high Ni mass (0.14-0.17 M ) erg/s) 43 (10

bol L Gaia data obtained from the Gaia Alert Stream; ZTF data obtained via MARS t (days)

Comparison sample from Valenti et al. 2016, MNRAS, 459, 3939 and to KSP-SN-2016kf from Afsariardchi et al. 2019, ApJ 881:22. SN1987A data from Berstenet al. 2009, ApJ 701:1. High expansion velocities

P60 spectrum from Fremling et al. 2018, TNS Classification Report 1765 Occured in outskirts of host galaxy

Low metallicity?

Time-weighted integrated bolometric luminosity (ET) is influenced by progenitor radius, ejecta mass and velocity (Shussman et al. 2016):

Based on bolometric luminosity, SN 2018hmx has an ET of 1.5*1056 erg*s. Using the Fe II 5169A velocity on day 50 as an approximation for ejecta 47 velocity, ET/vej is 2.68*10 gr*cm. These values are high compared to normal SNe II checked by Shussman Comparison sample from Guiterrez et al. 2017 ApJ 850, 90; iPTF14hls data from et al., but still consistent with a normal Type II RSG progenitor mass Arcavi et al. 2017, Nature, 551, 210; SN 2018aad data from Hiramatsu et al. in prep; and radius given the uncertainties in the normalization. KSP-SN-2016kf data from Afsariardchi et al. 2019, ApJ 881:22.

Take-home: SN 2018hmx is an extreme example of a high Ni-mass type II SN. The high Ni mass may be linked to the high luminosity and velocities, but not to extreme progenitor parameters (based on the calculated ET). Low metallicity may also play a role, as seen by the location in the host, and based on some similarities to KSP-SN-2016kf.

See poster by Shahar Bracha (#2) Bracha et al. In prep. The Fast & The Luminous Luminous Rapidly Evolving Events

Drout et al. (2014) Arcavi et al. (2016) Luminous Rapidly Evolving Events

Drout et al. (2014) Arcavi et al. (2016) Rest et al. (2018) Fast & Luminous Can’t be Solely Powered by Nickel

~M (assuming a central power source and constant opacity) Data sources: 1/2 ej 1/2 1/2 0.01 0.07 0.3 0.8 7 28 77 M-24 v  Arcavi+ 2011, 2016 tpeak 2.7d 2 Dougie 2 1 Bignotti+1998 ⇡ 10 M 0.1c 1 cm g Drout+ 2011, 2014 ✓ -23 ◆ ⇣ ⌘ ✓ ◆ Fassia+ 2000 Can’t be Powered by PTF09cnd (SLSN-I) Gal-Yam+ 2009 SN2006gy (SLSN-II) -22 Central Ni Decay Greiner+ 2015

SN2007bi (SLSN-R) Kasliwal+ 2011 Leonard+ 2000 -21 Li+ 1998 iPTF16asu SNLS04D4ec Liu+ 2000 SNLS05D2bk SNLS06D1hc -20 PTF10iam SN 2011kl SN 2018gep Nakamura+1998 Ofek+ 2007, 2010 -19 KSN 2015K SN 2011fe (Ia) Poznanski+ 2011 Peak R or r Magnitude

SN 2002bj Pritchard+ 2019 Quimby+2011 -18 PS1 Fast-Evolvers SNe Ib/c Rest+ 2018 (gold sample) Smith+ 2007 -17 SN 2010X SN 2011dh (SN IIb) Taddia+ 2015 Vinko+ 2012, 2015 -16 Whitesides+ 2017 1 10 100 t [Days] rise Adapted from Arcavi et al. (2016) Vinko et al. (2015) 1/2 1/2 1/2 Fast & Luminous Are Probably More than One Class M v  tpeak 2.7d 2 2 1 ⇡ 10 M 0.1c 1 cm g ✓ ◆ ✓ ◆ ~M (assuming a central power source and constant opacity) Data sources: ⇣ ⌘ 1/2 ej 1/2 1/2 0.01 0.07 0.3 0.8 7 28 77 M-24 v  Arcavi+ 2011, 2016 tpeak 2.7d 2 Dougie 2 1 Bignotti+1998 ⇡ 10 M 0.1c 1 cm g Drout+ 2011, 2014 ✓ -23 ◆ ⇣ ⌘ ✓ ◆ Fassia+ 2000 Can’t be Powered by PTF09cnd (SLSN-I) Gal-Yam+ 2009 SN2006gy (SLSN-II) -22 Central Ni Decay Greiner+ 2015

SN2007bi (SLSN-R) Kasliwal+ 2011 Leonard+ 2000 -21 Li+ 1998 Whitesides et al. (2017) iPTF16asu SNLS04D4ec Liu+ 2000 SNLS05D2bk SNLS06D1hc -20 PTF10iam SN 2011kl SN 2018gep Nakamura+1998 Ofek+ 2007, 2010 Pritchard et al. (2019) -19 KSN 2015K SN 2011fe (Ia) Poznanski+ 2011 Peak R or r Magnitude

• Luminous, very rapid decline (~1-2 mags per week) • Mostly featureless blue continuum, some broad features reported

Perley et al. 2019 Holy (AT 2018)cow! Very Fast, Luminous, Blue

• Luminous, very rapid decline (~1-2 mags per week) • Mostly featureless blue continuum, some broad features reported

Margutti et al. 2019 Perley et al. 2019 AT 2018cow Ventures into Extreme Region of this Phase Space

SN2007bi (SLSN-R) Kasliwal+ 2011 Leonard+ 2000 -21 Li+ 1998 iPTF16asu SNLS04D4ec Liu+ 2000 SNLS05D2bk SNLS06D1hc -20 PTF10iam SN 2011kl SN 2018cow SN 2018gep Nakamura+1998 Ofek+ 2007, 2010 -19 KSN 2015K SN 2011fe (Ia) Perley+ 2019 Peak R or r Magnitude

SN 2002bj Poznanski+ 2011 Pritchard+ 2019 -18 PS1 Fast-Evolvers SNe Ib/c Quimby+2011 (gold sample) Rest+ 2018 -17 SN 2010X SN 2011dh (SN IIb) Smith+ 2007 Taddia+ 2015 -16 Vinko+ 2012, 2015 1 10 100 t [Days] Whitesides+ 2017 rise Adapted from Arcavi et al. (2016) Is AT 2018cow “just” a Ibn?

• Luminous, very rapid decline (~1-2 mags per week) • Mostly featureless blue continuum, some broad features reported

Fox & Smith 2019

Margutti et al. 2019 Perley et al. 2019 Is AT 2018cow “just” a Ibn?

• Luminous, very rapid decline (~1-2 mags per week) • Mostly featureless blue continuum, some broad features reported

He He He

Fox & Smith 2019

Margutti et al. 2019 Perley et al. 2019 Are Other Events here “just” Ibn’s?

~M (assuming a central power source and constant opacity) Data sources: 1/2 ej 1/2 1/2 0.01 0.07 0.3 0.8 7 28 77 M-24 v  Arcavi+ 2011, 2016 tpeak 2.7d 2 Dougie 2 1 Bignotti+1998 ⇡ 10 M 0.1c 1 cm g Drout+ 2011, 2014 ✓ -23 ◆ ⇣ ⌘ ✓ ◆ Fassia+ 2000 PTF09cnd (SLSN-I) Gal-Yam+ 2009 SN2006gy (SLSN-II) -22 Greiner+ 2015

SN 2002bj Poznanski+ 2011 Pritchard+ 2019 -18 PS1 Fast-Evolvers SNe Ib/c Quimby+2011 (gold sample) Courtesy: G. Hosseinzadeh Rest+ 2018 -17 SN 2010X SN 2011dh (SN IIb) Smith+ 2007 Taddia+ 2015 -16 Vinko+ 2012, 2015 1 10 100 t [Days] Whitesides+ 2017 rise Adapted from Arcavi et al. (2016) Fast & Luminous Phase Space is Being Filled (but with what?)

~M (assuming a central power source and constant opacity) Data sources: 1/2 ej 1/2 1/2 0.01 0.07 0.3 0.8 7 28 77 M-24 v  Arcavi+ 2011, 2016 tpeak 2.7d 2 Dougie 2 1 Bignotti+1998 ⇡ 10 M 0.1c 1 cm g Drout+ 2011, 2014 ✓ -23 ◆ ⇣ ⌘ ✓ ◆ Fassia+ 2000 PTF09cnd (SLSN-I) DES Fast-Evolvers Gal-Yam+ 2009 (gold sample) SN2006gy (SLSN-II) -22 Greiner+ 2015

SN2007bi (SLSN-R) Hosseinzadeh+ 17 Kasliwal+ 2011 -21 Leonard+ 2000 iPTF16asu SNLS04D4ec Li+ 1998 SNe Ibn SNLS05D2bk SNLS06D1hc -20 PTF10iam SN 2011kl SN 2018cow SN 2018gep Liu+ 2000 Nakamura+1998 -19 KSN 2015K SN 2011fe (Ia) Ofek+ 2007, 2010 Peak R or r Magnitude

SN 2002bj Perley+ 2019 Poznanski+ 2011 -18 PS1 Fast-Evolvers SNe Ib/c Pritchard+ 2019 (gold sample) Pursiainen+ 2017 -17 SN 2010X SN 2011dh (SN IIb) Quimby+2011 Rest+ 2018 -16 Smith+ 2007 1 10 100 t [Days] Taddia+ 2015 rise Vinko+ 2012, 2015 Adapted from Arcavi et al. (2016) Whitesides+ 2017 The Fast & The Faint Ca-Strong Transients - Faint and Fast

Points = Ca-Rich SN 2005E Lines = Ib SN 2008D condensed in time x2

Perets et al. 2010 See also Valenti et al. 2014 Ca-Strong Transients - Faint and Fast Kasliwal et al. 2012

Perets et al. 2010 See also Valenti et al. 2014 Lunnan et al. 2017 Ca-Strong Transients - Faint and Fast Kasliwal et al. 2012

A&A proofs: manuscript no. aanda

Prentice et al. 2019 McBrien et al. 2019 SN 2018kzr

SN 2002bj

Poznanski et al. 2010

SN 2019bkc

(see also Chen et al. 2019) Fig. 4. Peak absolute magnitude in B or g as a function of decline rate for a selection of transients and SN 2019bkc. Di↵erences in magnitude Perets et al.system 2010 and ﬁlter bandpass are negligible for the purpose of this plot See also Valenti et al. 2014 which shows that the rapid decline of SNLunnan 2019bkc et is al. unprecedented 2017 compared to the comparison objects. The SNe Ia data are from Galbany et al. (2019).

half its peak luminosity is 4.01 0.04 d. SN 2019bkc reached a similar peak luminosity to 56Ni-driven± core-collapse events but approximately 10 times lower than that of thermonuclear SNe Ia. A rise time of 5 6 d is short but not excessively so, whis is similar to iPTF14gqr.⇠ However, its subsequent rapid decline is only rivalled by that of kilonova AT 2017gfo (e.g. Drout et al. 2017; Smartt et al. 2017), but the two are not spectroscopically similar. On the assumption that the light curve peak is powered by 56Ni decay (and excluding in this scenario the presence of short- lived radioisotopes), we use the analytical form of “Arnett’s rule” (Arnett 1982) as given in Stritzinger & Leibundgut (2005) to find the 56Ni mass required to give these peak luminosities. The rise Fig. 3. (Top) g-band light curves of various fast transients; SN 2019bkc time of the light curve is taken to be 5 d by assuming the and the Ca-rich SNe 2010et , 2012hn, iPTF14gqr, and iPTF16hgs. The explosion date to be midway between the⇠ ATLAS non-detection red line is the ELDD-L model from Sim et al. (2012). The inset shows and the first ZTF detection (MJD 58540.9 0.4). These values are the g band light curve with an estimated upper limit of 19.5 mag (green ± found to be MNi 0.031 M and MNi 0.037 M for the griz star) derived from the ATLAS-o band magnitude of 19.8 assuming the ⇠ ⇠ SED is a black body at 20000 K. (Middle) r or R band light curves and ugriz luminosities, respectively. This method also assumes 56 including SNe Ic 2005ek⇠ and 1994I, and the unusual transients SNe that the Ni is located centrally, which may not be valid for this 2010X and 2002bj. (Bottom) i or I band comparison with the addition event (see Khatami & Kasen 2019), thus these values should be of the Ti-dominated transient OGLE-2013-SN-079. The initial ATLAS- considered upper limits. o non-detection is treated as if it was in r and i respectively. We also estimated the ejecta mass Mej using the formulation given in Arnett (1982) and expressed as sults in a synthetic g magnitude limit of 19.8 > g > 19.1 mag 1 c 2 4 5 M = ⌧ v (1) for temperatures in the range, 10 < T < 10 K. At T = 25000 ej 2  m sc K the g limit is 19.5 mag. The inset in the top panel of Fig. 3 ✓ ◆ ⇠ shows that SN 2019bkc had a very sharp rise from non-detection where 13.7 is a constant of integration, ⌧m is a timescale ⇡ to detection before levelling o↵, this is dicult to reconcile with of the light curve model which can be approximated by the rise 2 a simple blast-wave approximation of L t , and we note that time, vsc is a scale velocity which we take to be a measured line the light curve of Ca-rich iPTF14gqr showed/ a double-peaked velocity around maximum light, and  is the opacity, which is 2 1 profile (De et al. 2018b). assumed to have a constant value of 0.07 cm g (for a discus- sion on appropriate choices of  see Taddia et al. 2018; Nagy 2018). Thus, using the ugriz rise time of 5 d and a scale velocity 1 3.2. Pseudo-bolometric light curve vsc = 14 500 km s from the Si ii 6355 line (see Section 4), we found Mej 0.4M . The griz and ugriz pseudo-bolometric light curves of SN ⇠ 2019bkc were constructed following the method in Prentice et al. (2016) and are shown in Fig 5 compared to other fast-evolving 4. Spectroscopy transients. A simple polynomial fit to the light curves shows it 42 1 reached a griz peak of (1.41 0.06) 10 erg s in 6.1 0.4d Spectra of SN 2019bkc were taken over a 20 day period cover- after estimated explosion and±ugriz peak⇥ of (1.9 0.1) 10±42 erg ing from shortly before maximum light until well into the de- s 1 in 5.0 0.4 d. The time for the griz light curve± to⇥ decay by cay phase (Fig. 6). The epochs that spectra were taken at are ± Article number, page 6 of 16 Ca-Strong Transients - Diverse Photospheric Spectra

Diverse in Photospheric Phase Similar in Nebular Phase

Lunnan et al. 2017 Ca-Strong Transients - Remote Positions

Perets et al. 2010

Kasliwal et al. 2012 Ca-Strong Transients - Remote Positions

Lunnan et al. 2017 Ca-Strong Transients - From White Dwarfs in Globular Clusters?

Globar clusters have increased rates of:

O/Ne WD Mergers

TDEs of He WDs by NSs

Accretion from He-burning stars to WDs

Then ejected from the cluster

Shen et al. 2019 The Incredibly Fast (aka The Kilonova) Fastest ‘Bright’ Transient: The GW170817 Kilonova

~M (assuming a central power source and constant opacity) ej 0.01 0.07 0.3 0.8 7 28 77 −19 -24 Dougie 7ySe Ia −18 sXSernova -23 PTF09cnd (SLSN-I) 7ySe Ib/c DES Fast-Evolvers (gold sample) SN2006gy (SLSN-II) −17 sXSernova -22 SN2007bi (SLSN-R)

61 2002bj -21 −16 iPTF16asu SNLS04D4ec SNe Ibn SNLS05D2bk SNLS06D1hc -20 PTF10iam SN 2011kl −15 SN 2018cow SN 2018gep

61 2010X -19 KSN 2015K SN 2011fe (Ia) Peak R or r Magnitude

AbsolXte magnitXde AbsolXte −14 SN 2002bj

-18 61 1999em + 1 PS1 Fast-Evolvers SNe Ib/c −13 (gold sample)

Kilonova -17 SN 2010X SN 2011dh (SN IIb) −12 -16 −20 −10 0 10 20 30 1 10 100 t [Days] 7ime Irom SeaN (rest-Irame days) rise Arcavi et al. 2017 Compilation from: Arcavi 2018

Data from: Andreoni et al. 2017, Arcavi et al. 2017, Cowperthwaite et al. 2017, Coulter et al. 2017, Diaz et al. 2017, Drout et al. 2017, Evans et al. 2017, Hu et al. 2017, Kasliwal et al. 2017, Lipunov et al. 2017, Pian et al. 2017, Pozanenko et al. 2017, Shapee et al. 2017, Smartt et al. 2017, Tanvir et al. 2017, Troja et al. 2017, Utsumi et al. 2017, Valenti et al. 2017.

Retrieved via: kilonovae.space Single component radioactive decay can not explain all bands.

Compilation from: Arcavi 2018

Retrieved via: kilonovae.space Three component radioactive decay model gives a better fit (10 parameters).

Compilation from: Arcavi 2018

Retrieved via: kilonovae.space Different emission components can come Mass Ratio NS Radius from different ejecta components.

Merger Product Different Models for the Blue → Red Emission

Multi-component radioactive decay Villar et al. 2017

Single-component radioactive decay (time-varying opacity) Waxman et al. 2017

Boosted relativistic ejecta (early blue-emission) Kasliwal et al. 2017, see also Nakar & Piran 2017, Gottlieb et al. 2017

Shock cooling (early blue-emission) Piro & Kollmeier 2017 7ime Vince merger (reVt-frDme KRurV) 7iPe since Perger (resW-frDPe KRurs) 10 30 80 10 30 80

VillDr et Dl. (2017), RDdiRDctive DecDy -22 WDxPDn eW Dl. (2017), RDdiRDcWive DecDy -22 .DVliwDl et Dl. (2017), 6KRck &RRling 3irR & .RllPeier (2017), 6KRck &RRling & BRRVted RDdiRDctive DecDy 12 12

-20 -20

14 14

-18 -18

16 16

-16 -16

18 18

-14 -14

20 20 AbsRluWe PDgniWude AbsRluWe ASSDrent mDgnitude ASSDrent

-12 -12

22 22

-10 -10

24 24

-8 -8

26 26 Arcavi 2018 0.4 1 3 0.4 1 3 7ime Vince merger (reVt-frDme dDyV) 7iPe since Perger (resW-frDPe dDys) Predicted One-Hour Time Scale Blue Emission

Metzger et al. 2015 Optical-UV Observations in the first ~hour after a NS mereger followed by sub-day cadence ARE CRUCIAL The “Treasure Map” http://treasuremap.space

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* Sam Wyatt (U of A), lead programmer * Aaron Tohuvavohu (U of Toronto), Visualization * And: Iair Arcavi (TAU), Dave Sand & Michael Lundquist (U of A), Andy Howell & Austin Riba (Las Cumbres Observatory) Summary - Just a Subset of Extreme SNe

Slow - • OGLE14-073, 14hls - What is/are the power source(s) & progenitor(s)? • 2018hmx - Link between large Ni production and high velocities?

Fast & Luminous - • Rapidly rising luminous transients - What are the power source & progenitors? • AT 2017cow - IMBH TDE? Central engine? Ibn? (what makes a Ibn anyway?)

Fast & Faint - • Ca-strong - What are the progenitors? Why so far from host?

Extremely Fast - • Kilonovae: Lots of physics to learn from first hours, requires coordination!