The Spectroscopic Classification of Astronomical Transients (SCAT) Survey: Overview, Pipeline Description, Initial Results, and Future Plans

Abstract

We present the Spectroscopic Classification of Astronomical Transients (SCAT) survey, which is dedicated to spectrophotometric observations of transient objects such as supernovae and tidal disruption events. SCAT uses the SuperNova Integral-Field Spectrograph (SNIFS) on the University of Hawai'i 2.2-meter (UH2.2m) telescope. SNIFS was designed specifically for accurate transient spectrophotometry, including absolute flux calibration and host-galaxy removal. We describe the data reduction and calibration pipeline including spectral extraction, telluric correction, atmospheric characterization, nightly photometricity, and spectrophotometric precision. We achieve $\lesssim 5\%$ spectrophotometry across the full optical wavelength range ($3500-9000\mathring{A}$) under photometric conditions. The inclusion of photometry from the SNIFS multi-filter mosaic imager allows for decent spectrophotometric calibration ($10-20\%$) even under unfavorable weather/atmospheric conditions. SCAT obtained $\approx 640$ spectra of transients over the first 3 years of operations, including supernovae of all types, active galactic nuclei, cataclysmic variables, and rare transients such as superluminous supernovae and tidal disruption events. These observations will provide the community with benchmark spectrophotometry to constrain the next generation of hydrodynamic and radiative transfer models.

12 pages, 9 figures, 2 tables. Accepted for publication in to PASP

References in corpus (25)

• Array Programming with NumPy
• Advanced Virgo: a 2nd generation interferometric gravitational wave detector
• GWTC-2: Compact Binary Coalescences Observed by LIGO and Virgo During the First Half of the Third Observing Run
• Swope Supernova Survey 2017a (SSS17a), the Optical Counterpart to a Gravitational Wave Source
• The All-Sky Automated Survey for Supernovae (ASAS-SN) Light Curve Server v1.0
• Molecfit: A general tool for telluric absorption correction. I. Method and application to ESO instruments
• Determining the Type, Redshift, and Age of a Supernova Spectrum
• Molecfit: A general tool for telluric absorption correction II. Quantitative evaluation on ESO-VLT X-Shooter spectra
• The discovery of the electromagnetic counterpart of GW170817: kilonova AT 2017gfo/DLT17ck
• The Zwicky Transient Facility: Surveys and Scheduler
• PESSTO : survey description and products from the first data release by the Public ESO Spectroscopic Survey of Transient Objects
• The Zwicky Transient Facility Bright Transient Survey. II. A Public Statistical Sample for Exploring Supernova Demographics
• Techniques and Review of Absolute Flux Calibration from the Ultraviolet to the Mid-Infrared
• Discovery and Follow-up of ASASSN-19dj: An X-ray and UV Luminous TDE in an Extreme Post-Starburst Galaxy
• A new class of flares from accreting supermassive black holes
• A WC/WO star exploding within an expanding carbon-oxygen-neon nebula
• High-efficiency Autonomous Laser Adaptive Optics
• The Rise and Fall of ASASSN-18pg: Following a TDE from Early To Late Times
• Photometric and spectroscopic observations, and abundance tomography modelling of the type Ia supernova SN 2014J located in M82
• A Carbon/Oxygen-dominated Atmosphere Days After Explosion for the "Super-Chandrasekhar" Type Ia SN 2020esm
• The Changing Look Blazar B2 1420+32
• Large Adaptive Optics Survey for Substellar Objects (LASSO) Around Young, Nearby, Low-mass Stars with Robo-AO
• ASAS-SN follow-up of IceCube high-energy neutrino alerts
• Mauna Kea Sky Transparency from CFHT SkyProbe Data
• SCALA: In-situ calibration for Integral Field Spectrographs

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