Processing Images from the Zwicky Transient Facility

Laher, Russ R.; Masci, Frank J.; Groom, Steve; Rusholme, B.; Shupe, D. L.; Jackson, Edward F.; Surace, J.; Flynn, Dave; Landry, Walter; Terek, Scott; Hélou, G.; Beck, R.; Hacopians, Eugean; Rebbapragada, Umaa; Bue, Brian D.; Smith, Roger M.; Dekany, Richard; Miller, A. A.; Cenko, S. B.; Bellm, Eric C.; Patterson, Maria T.; Kupfer, Thomas; Yang, Lin; Barlow, Tom A.; Graham, M. J.; Kasliwal, Mansi M.; Prince, Thomas A.; Kulkarni, S. R.

doi:10.48550/arxiv.1708.01584

Cited by 3 publications

(3 citation statements)

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“…Transient Facility (e.g., Bellm et al 2015;Laher et al 2017) are deployed, many more interacting SNe will be observed and quickly followed up with multiple-band observations. These may also be the brightest sources for the ULTRASAT U V satellite mission (Sagiv et al 2014).…”

Section: Discussionmentioning

confidence: 99%

Supernova PTF 12glz: A Possible Shock Breakout Driven through an Aspherical Wind

Soumagnac

Ofek

Gal‐Yam

et al. 2019

ApJ

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We present visible-light and ultraviolet (U V ) observations of the supernova PTF 12glz. The SN was discovered and monitored in near-U V and R bands as part of a joint GALEX and Palomar Transient Factory campaign. It is among the most energetic Type IIn supernovae observed to date (≈ 10 51 erg). If the radiated energy mainly came from the thermalization of the shock kinetic energy, we show that PTF 12glz was surrounded by ∼ 1 M of circumstellar material (CSM) prior to its explosive death. PTF 12glz shows a puzzling peculiarity: at early times, while the freely expanding ejecta are presumably masked by the optically thick CSM, the radius of the blackbody that best fits the observations grows at ≈ 8000 km s −1 . Such a velocity is characteristic of fast moving ejecta rather than optically thick CSM. This phase of radial expansion takes place before any spectroscopic signature of expanding ejecta appears in the spectrum and while both the spectroscopic data and the bolometric luminosity seem to indicate that the CSM is optically thick. We propose a geometrical solution to this puzzle, involving an aspherical structure of the CSM around PTF 12glz. By modeling radiative diffusion through a slab of CSM, we show that an aspherical geometry of the CSM can result in a growing effective radius. This simple model also allows us to recover the decreasing blackbody temperature of PTF 12glz. SLAB-Diffusion, the code we wrote to model the radiative diffusion of photons through a slab of CSM and evaluate the observed radius and temperature, is made available on-line.

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Section: Discussionmentioning

confidence: 99%

Supernova PTF 12glz: A Possible Shock Breakout Driven through an Aspherical Wind

Soumagnac

Ofek

Gal‐Yam

et al. 2019

ApJ

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“…This represents the first direct measurement of the Ca-rich transient rate, and is equal to around ∼ 50% of the SN Ia rate at a similar redshift (Frohmaier et al, in prep). Combining our rate with assumptions on the performance of the Zwicky Transient Facility (ZTF) (Bellm 2014;Laher et al 2017), we estimate that ZTF should discover more than 20 Ca-rich transients each year. This order of magnitude improvement on the sample statistics will revolutionize the understanding on the volumetric rates, progenitors and environments of these events.…”

Section: The Rate Of Ca-rich Snementioning

confidence: 98%

The Volumetric Rate of Calcium-rich Transients in the Local Universe

Frohmaier

Sullivan

Maguire

et al. 2018

ApJ

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We present a measurement of the volumetric rate of 'calcium-rich' optical transients in the local universe, using a sample of three events from the Palomar Transient Factory (PTF). This measurement builds on a detailed study of the PTF transient detection efficiencies, and uses a Monte Carlo simulation of the PTF survey. We measure the volumetric rate of calcium-rich transients to be higher than previous estimates: 1.21 +1.13 −0.39 × 10 −5 events yr −1 Mpc −3 . This is equivalent to 33-94% of the local volumetric type Ia supernova rate. This calcium-rich transient rate is sufficient to reproduce the observed calcium abundances in galaxy clusters, assuming an asymptotic calcium yield per calciumrich event of ∼0.05 M . We also study the PTF detection efficiency of these transients as a function of position within their candidate host galaxies. We confirm as a real physical effect previous results that suggest calcium-rich transients prefer large physical offsets from their host galaxies.

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“…With first light at Palomar Observatory in 2017, the Zwicky Transient Facility (Kulkarni 2016) will scan more than 3750 deg 2 hr −1 to a depth of about 20 mag to discover young supernovae less than 24 hours after explosion each night, hunt for electromagnetic counterparts of gravitational-wave events (Ghosh et al 2017), and search for rare and exotic transients. Repeated imaging of the Northern sky, including the Galactic Plane, will produce a photometric variability catalog with nearly 300 observations each year (Laher et al 2017) for detailed studies of variable stars and binary systems. From its unique high earth orbit, the Transiting Exoplanet Survey Satellite aims to survey about 200,000 nearby G, K and M type stars with apparent magnitudes brighter than about 12 mag with a 1 minute cadence across a 400 deg 2 area of the sky (Ricker et al 2016;Sullivan et al 2015Sullivan et al , 2017 to open a new era on stellar variability.…”

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confidence: 99%

Modules for Experiments in Stellar Astrophysics (${\mathtt{M}}{\mathtt{E}}{\mathtt{S}}{\mathtt{A}}$): Convective Boundaries, Element Diffusion, and Massive Star Explosions

Paxton

Schwab

Bauer

et al. 2018

ApJS

1,891

1,706

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We update the capabilities of the software instrument Modules for Experiments in Stellar Astrophysics (MESA) and enhance its ease of use and availability. Our new approach to locating convective boundaries is consistent with the physics of convection, and yields reliable values of the convective core mass during both hydrogen and helium burning phases. Stars with M < 8 M become white dwarfs and cool to the point where the electrons are degenerate and the ions are strongly coupled, a realm now available to study with MESA due to improved treatments of element diffusion, latent heat release, and blending of equations of state. Studies of the final fates of massive stars are extended in MESA by our addition of an approximate Riemann solver that captures shocks and conserves energy to high accuracy during dynamic epochs. We also introduce a 1D capability for modeling the effects of Rayleigh-Taylor instabilities that, in combination with the coupling to a public version of the STELLA radiation transfer instrument, creates new avenues for exploring Type II supernovae properties. These capabilities are exhibited with exploratory models of pair-instability supernova, pulsational pair-instability supernova, and the formation of stellar mass black holes. The applicability of MESA is now widened by the capability of importing multi-dimensional hydrodynamic models into MESA. We close by introducing software modules for handling floating point exceptions and stellar model optimization, and four new software tools − MESA-Web, MESA-Docker, pyMESA, and mesastar.org − to enhance MESA's education and research impact.

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Processing Images from the Zwicky Transient Facility

Cited by 3 publications

References 0 publications

Supernova PTF 12glz: A Possible Shock Breakout Driven through an Aspherical Wind

Supernova PTF 12glz: A Possible Shock Breakout Driven through an Aspherical Wind

The Volumetric Rate of Calcium-rich Transients in the Local Universe

Modules for Experiments in Stellar Astrophysics (${\mathtt{M}}{\mathtt{E}}{\mathtt{S}}{\mathtt{A}}$): Convective Boundaries, Element Diffusion, and Massive Star Explosions

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