Extreme radio flares and associated X-ray variability from young stellar objects in the Orion Nebula Cluster

Abstract

Young stellar objects are known to exhibit strong radio variability on timescales of weeks to months, and a few reports have documented extreme radio flares, with at least an order of magnitude change in flux density on timescales of hours to days. However, there have been few constraints on the occurrence rate of such radio flares or on the correlation with pre-main sequence X-ray flares, although such correlations are known for the Sun and nearby active stars. Here we report simultaneous deep VLA radio and Chandra X-ray observations of the Orion Nebula Cluster, targeting hundreds of sources to look for the occurrence rate of extreme radio variability and potential correlation with the most extreme X-ray variability. We identify 13 radio sources with extreme radio variability, with some showing an order of magnitude change in flux density in less than 30 minutes. All of these sources show X-ray emission and variability, but only on timescales <1h do we find clear correlations with extreme radio flaring. Strong X-ray variability does not predict the extreme radio sources and vice versa. Radio flares thus provide us with a new perspective on high-energy processes in YSOs and the irradiation of their protoplanetary disks. Finally, our results highlight implications for interferometric imaging of sources violating the constant-sky assumption.

18 pages, 13 sources, 7 figures. ApJ, in press

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Cited by in corpus (10)

• A VLBA Survey of radio stars in the Orion Nebula Cluster: I. The nonthermal radio population
• Observing protoplanetary discs with the Square Kilometre Array -- I. Characterising pebble substructure caused by forming planets
• Non-thermal radio continuum emission from young nearby stars
• SMA detection of an extreme millimeter flare from the young class III star HD 283572
• The JCMT Transient Survey: Single Epoch Transients and Variability of Faint Sources
• A systematic survey of millimetre-wavelength flaring variability of Young Stellar Objects in the Orion Nebula Cluster
• From downtown to the outskirts: a radio survey of the Orion Nebula Cluster
• Detection of coherent low-frequency radio bursts from weak-line TTauri stars
• Characterising X-ray variability in light curves with complex sampling patterns: application to the eROSITA south ecliptic pole survey
• Large Dust Grains and a Possible Dust Trap in the Polar Circumbinary Disc of HD 98800B