The fast, luminous ultraviolet transient AT2018cow: extreme supernova, or disruption of a star by an intermediate-mass black hole?

Perley, D. A.; Mazzali, Paolo A.; Yan, Lin; Cenko, S. B.; Gezari, Suvi; Taggart, K.; Blagorodnova, N.; Fremling, C.; Mockler, Brenna; Singh, Avinash; Tominaga, Nozomu; Tanaka, Masaomi; Watson, A. M.; Ahumada, Tomás; Anupama, G. C.; Ashall, C.; Becerra, R. L.; Bersier, D.; Bhalerao, V.; Bloom, J.; Butler, Nathaniel R.; Copperwheat, C. M.; Coughlin, M. W.; De, Kishalay; Drake, A. J.; Duev, Dmitry A.; Frederick, Sara; González, J. Jesús; Goobar, A.; Heida, Marianne; Ho, Anna Y. Q.; Horst, J. Chuck; Hung, T.; Itoh, R.; Jencson, J.; Kasliwal, M. M.; Kawai, N.; Khanam, Tanazza; Kulkarni, S. R.; Kumar, Brajesh; Kumar, Harsh; Kutyrev, A.; Lee, William H.; Maeda, Keiichi; Mahabal, A.; Murata, Katsuhiro L.; Neill, James D.; Ngeow, Chow-Choong; Penprase, Bryan E.; Pian, E.; Quimby, R.; Ramírez-Ruiz, E.; Richer, M. G.; Román-Zúñiga, C.; Sahu, D. K.; Srivastav, Shubham; Socia, Q.; Sollerman, J.; Tachibana, Y.; Taddia, F.; Tinyanont, Samaporn; Troja, E.; Ward, Charlotte; Wee, Jerrick; Yu, Po Chieh

doi:10.1093/mnras/sty3420

Cited by 197 publications

(378 citation statements)

References 95 publications

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“…Figure 5 shows the rate of brightness change at λ rest ∼ 3400Å as a function of the absolute magnitude (based on the brighter of the two observations used for the rate estimate), while Figure 6 shows the absolute magnitude at λ rest ∼ 3400Å as a function of the time scale of the variability. Figure 7 diagram of other SNe and transients is derived from the u-and b-band light curves of nearby SNe obtained by the Swift Ultraviolet/Optical Telescope (UVOT) (Nugent et al 2011;Brown et al 2012;Pritchard et al 2014), the U -and B-band light curves of SN 1993J (Richmond et al 1994(Richmond et al , 1996, the g-and r-band light curves of PTF 09uj after the shock breakout obtained by PTF (Ofek et al 2010), the g-and r-band light curves of PS1-13arp after the shock breakout and rapid transients obtained by Pan-STARRS1 (Gezari et al 2015;Drout et al 2014), the g-and r-band light curves of the rapidly rising transients obtained by HSC (Tanaka et al 2016), uvw1-, u-, and g-band light curves of a fast luminous ultraviolet transient AT2018cow (Prentice et al 2018;Perley et al 2019), and U -, g-, and r-band light curves of a kilonova (AT2017gfo) associated with a gravitational wave source GW170817 (Andreoni et al 2017;Arcavi et al 2017;Coulter et al 2017;Cowperthwaite et al 2017;Díaz et al 2017;Drout et al 2017;Evans et al 2017;Valenti et al 2017;Kasliwal et al 2017;Pian et al 2017;Shappee et al 2017;Smartt et al 2017;Utsumi et al 2017, summarized in Villar et al 2017. We apply K-corrections by interpolating or extrapolating their spectral energy distributions in magnitude.…”

Section: Comparisons With Known Transientsmentioning

confidence: 99%

A Rapidly Declining Transient Discovered with the Subaru/Hyper Suprime-Cam

Tominaga

Morokuma

Tanaka

et al. 2019

ApJ

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We perform a high-cadence transient survey with Subaru Hyper Suprime-Cam (HSC), which we call the Subaru HSC survey Optimized for Optical Transients (SHOOT). We conduct HSC imaging observations with time intervals of about one hour on two successive nights, and spectroscopic and photometric follow-up observations. A rapidly declining blue transient SHOOT14di at z = 0.4229 is found in observations on two successive nights with an image subtraction technique. The rate of brightness change is +1.28 +0.40 −0.27 mag day −1 (+1.83 +0.57 −0.39 mag day −1 ) in the observer (rest) frame and the rest-frame color between 3400 and 4400Å is MThe nature of the object is investigated by comparing its peak luminosity, decline rate, and color with those of transients and variables previously observed, and those of theoretical models. None of the transients or variables share the same properties as SHOOT14di. Comparisons with theoretical models demonstrate that, while the emission from the cooling envelope of a Type IIb supernova shows a slower decline rate than SHOOT14di, and the explosion of a red supergiant star with a dense circumstellar wind shows a redder color than SHOOT14di, the shock breakout at the stellar surface of the explosion of a 25M ⊙ red supergiant star with a small explosion energy of ≤ 0.4 × 10 51 erg reproduces the multicolor light curve of SHOOT14di. This discovery shows that a high-cadence, multicolor optical transient survey at intervals of about one hour, and continuous and immediate follow-up observations, is important for studies of normal core-collapse supernovae at high redshifts.

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Section: Comparisons With Known Transientsmentioning

confidence: 99%

A Rapidly Declining Transient Discovered with the Subaru/Hyper Suprime-Cam

Tominaga

Morokuma

Tanaka

et al. 2019

ApJ

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“…The FBOT AT2018cow was identified in the Asteroid Terrestrial-impact Last Alert System (ATLAS) survey on 16 June 2018 , hosted in the dwarf spiral galaxy CGCG 137-068 at a redshift of 0.014 (Prentice et al 2018). It shows peculiar properties: the fastest rise with a timescale < 3.3 days, a t 1/2 of < 1.7 days (during the rising phase), a high peak luminosity of (1.7 − 4.0) × 10 44 erg s −1 (exceeding that of super-luminous supernovae), and an unusual featureless non-evolving early-phase spectrum (Prentice et al 2018) followed by a rapid decline in the light curve (Prentice et al 2018;Perley et al 2019;Margutti et al 2019). This made it one of the most extreme amongst the current sample of FBOTs and thus presented a unique opportunity for the continued monitoring to help clarify its origin and physical properties.…”

Section: Introductionmentioning

confidence: 99%

“…Multi-wavelength studies of AT2018cow mostly probed the early optically thick rising phase of spectral evolution (Prentice et al 2018;Rivera Sandoval et al 2018;Perley et al 2019;Kuin et al 2019;Ho et al 2019;Margutti et al 2019). Optical spectroscopy indicates a peak blackbody temperature of ≈ 27000 K, ejecta mass of 0.1 -0.4 M and a transition from an initial featureless spectrum to the appearance of distinct broad H and He emission lines only after 15 days from the discovery (Prentice et al 2018;Perley et al 2019;Margutti et al 2019). The early X-ray flux was variable over day timescales, suggestive of a shock interacting with a non-uniform surrounding medium .…”

Section: Introductionmentioning

confidence: 99%

“…A powering by the radioactive decay of 56 Ni, expected in core-collapse supernovae was ruled out based on an nonphysical requirement on the Ni mass (≈ 3 M ) in comparison to the inferred ejecta mass of ≈ 0.1 -0.4 M and the inability to account for the light curve decay (Prentice et al 2018). Powering by the tidal disruption of a white dwarf star by an intermediate mass black hole (10 4 M ) (Perley et al 2019;Kuin et al 2019) was disfavored owing to a dense Ho et al 2019) highly magnetized (Huang et al 2019) environment inferred in the immediate vicinity of the transient, which may be challenging to naturally develop in this scenario and require a pre-existing reservoir . The absence of excitation H and He narrow lines following the transition from a high velocity expansion (≥ 0.1c) to a slower one (≈ 0.02 c) seem to disfavor an origin in a failed regular supernovae of a giant star (with a consequent direct collapse to a black hole) (Perley et al 2019).…”

Section: Introductionmentioning

confidence: 99%

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The Nearby Luminous Transient AT2018cow: A Magnetar Formed in a Subrelativistically Expanding Nonjetted Explosion

Mohan

Yang

2020

ApJL

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The fast-rising blue optical transient AT2018cow indicated unusual early phase characteristics unlike relatively better studied explosive transients. Its afterglow may be produced by either a relativistically beamed (jetted) or intrinsically luminous (non-jetted) ejecta and carries observational signatures of the progenitor and environment. High resolution monitoring can distinguish between these scenarios and clarify the progenitor nature. We present very long baseline interferometry (VLBI) observations of AT2018cow at 5 GHz involving 21 radio telescopes from the European VLBI Network with five sessions spanning ≈ 1 year. With an astrometric precision up to 25 micro-arcseconds (µas) per epoch, the rapidly fading compact mas scale source is found to be non-jetted with a proper motion of ≤ 0.15 mas yr −1 (0.14 c). This and a dense (number density ≈ 10 4 − 10 5 cm −3 ) magnetized environment (magnetic field strength ≥ 0.84 G) are characteristic of a newly formed magnetar driven central engine, originating in the successful explosion of a low-mass star.

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“…A new paradigm of astronomical data collection has been realized over the past decade. Dozens of projects 1 probing the time-variable universe have led to new discoveries (e.g., Arcavi et al 2016;Lunnan et al 2017;Margutti et al 2019;Perley et al 2019), higher quality data-sets and statistics (e.g., Graur et al 2017;Brout et al 2019) and improvements in our understanding of the physics governing transient phenomena. The advent of the Rubin Observatory Legacy Survey of Space and Time (LSST) (Tyson 2002;Ivezic et al 2008;Ivezić et al 2019) in the upcoming decade, delivering an order of magnitude higher volume of alerts, will be transformative.…”

Section: Introductionmentioning

confidence: 99%

Real-time, Value-driven Data Augmentation in the Era of LSST

Sravan

Milisavljevic

Reynolds

et al. 2020

ApJ

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The deluge of data from time-domain surveys is rendering traditional human-guided data collection and inference techniques impractical. We propose a novel approach for conducting data collection for science inference in the era of massive large-scale surveys that uses value-based metrics to autonomously strategize and co-ordinate follow-up in real-time. We demonstrate the underlying principles in the Recommender Engine For Intelligent Transient Tracking (REFITT) that ingests live alerts from surveys and value-added inputs from data brokers to predict the future behavior of transients and design optimal data augmentation strategies given a set of scientific objectives. The prototype presented in this paper is tested to work given simulated Rubin Observatory Legacy Survey of Space and Time (LSST) core-collapse supernova (CC SN) light-curves from the PLAsTiCC dataset. CC SNe were selected for the initial development phase as they are known to be difficult to classify, with the expectation that any learning techniques for them should be at least as effective for other transients. We demonstrate the behavior of REFITT on a random LSST night given ∼32000 live CC SNe of interest. The system makes good predictions for the photometric behavior of the events and uses them to plan follow-up using a simple data-driven metric. We argue that machine-directed follow-up maximizes the scientific potential of surveys and follow-up resources by reducing downtime and bias in data collection.

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The fast, luminous ultraviolet transient AT2018cow: extreme supernova, or disruption of a star by an intermediate-mass black hole?

Cited by 197 publications

References 95 publications

A Rapidly Declining Transient Discovered with the Subaru/Hyper Suprime-Cam

A Rapidly Declining Transient Discovered with the Subaru/Hyper Suprime-Cam

The Nearby Luminous Transient AT2018cow: A Magnetar Formed in a Subrelativistically Expanding Nonjetted Explosion

Real-time, Value-driven Data Augmentation in the Era of LSST

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