The JCMT Transient Survey: Single Epoch Transients and Variability of Faint Sources

Abstract

Short-duration flares at millimeter wavelengths provide unique insights into the strongest magnetic reconnection events in stellar coronae, and combine with longer-term variability to introduce complications to next-generation cosmology surveys. We analyze 5.5 years of JCMT Transient Survey 850 micron submillimeter monitoring observations toward eight Gould Belt star-forming regions to search for evidence of transient events or long-duration variability from faint sources. The eight regions (30 arcmin diameter fields), including ~1200 infrared-selected YSOs, have been observed on average 47 times with integrations of approximately half an hour, or one day total spread over 5.5 years. Within this large data set, only two robust faint source detections are recovered: JW 566 in OMC 2/3 and MGM12 2864 in NGC 2023. JW 566, a Class II TTauri binary system previously identified as an extraordinary submillimeter flare, remains unique, the only clear single-epoch transient detection in this sample with a flare eight times bright than our ~4.5 sigma detection threshold of 55 mJy/beam. The lack of additional recovered flares intermediate between JW 566 and our detection limit is puzzling, if smaller events are more common than larger events. In contrast, the other submillimeter variable identified in our analysis, Source 2864, is highly variable on all observed timescales. Although Source 2864 is occasionally classified as a YSO, the source is most likely a blazar. The degree of variability across the electromagnetic spectrum may be used to aid source classification.

Accepted for publication in the Astrophysicall Journal. 17 pages, 6 figures, 2 tables

References in corpus (29)

• A Spitzer Survey of Young Stellar Clusters within One Kiloparsec of the Sun: Cluster Core Extraction and Basic Structural Analysis
• SCUBA-2: iterative map-making with the Sub-Millimetre User Reduction Facility
• The Gould's Belt Distances Survey (GOBELINS) II. Distances and structure towards the Orion Molecular Clouds
• The James Clerk Maxwell Telescope Legacy Survey of Nearby Star-forming Regions in the Gould Belt
• Neon Fine-Structure Line Emission By X-ray Irradiated Protoplanetary Disks
• Quantifying Variability of YSOs in the Mid-IR Over Six Years with NEOWISE
• How do stars gain their mass? A JCMT/SCUBA-2 Transient Survey of Protostars in Nearby Star Forming Regions
• A Decade of SCUBA-2: A Comprehensive Guide to Calibrating 450 $\mu$m and 850 $\mu$m Continuum Data at the JCMT
• Synchrotron emission from the T Tauri binary system V773 Tau A
• The Close Binary Fraction as a Function of Stellar Parameters in APOGEE: A Strong Anti-Correlation With $\alpha$ Abundances
• Variable H${}^{13}$CO${}^{+}$ Emission in the IM Lup Disk: X-ray Driven Time-Dependent Chemistry?
• X-ray Super-Flares From Pre-Main Sequence Stars: Flare Energetics And Frequency
• The JCMT Transient Survey: Detection of sub-mm variability in a Class I protostar EC 53 in Serpens Main
• The JCMT Transient Survey: Data Reduction and Calibration Methods
• The Relationship between Mid-Infrared and Sub-Millimetre Variability of Deeply Embedded Protostars
• The Gould's Belt Very Large Array Survey III. The Orion region
• Captured at Millimeter Wavelengths: a Flare from the Classical T Tauri Star DQ Tau
• Detection of Galactic and Extragalactic Millimeter-Wavelength Transient Sources with SPT-3G
• A 1.3 cm wavelength radio flare from a deeply embedded source in the Orion BN/KL region
• Radiative Transfer modeling of EC 53: An Episodically Accreting Class I Young Stellar Object
• ALMA photometry of extragalactic radio sources
• Observational signatures of outbursting protostars -- II: Exploring a wide range of eruptive protostars
• Characterising the i-band variability of YSOs over six orders of magnitude in timescale
• Extreme radio flares and associated X-ray variability from young stellar objects in the Orion Nebula Cluster
• Dissecting the different components of the modest accretion bursts of the very young protostar HOPS 373
• Low Mass Stars as Tracers of Star and Cluster Formation
• AGB interlopers in YSO catalogues hunted out by NEOWISE
• A New Multi-Wavelength Census of Blazars
• Simultaneous Detection of Optical Flares of the Magnetically Active M Dwarf Wolf 359

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