James Webb Space Telescope Feed Post

Webb's PEARLS: Transients in the MACS J0416.1-2403 Field

(top row) Color images of SN01 in four epochs, with the scale and orientation noted. The position of the SN is indicated by the red arrow in each image. The nearby irregular galaxy is presumably the host, which is at z = 2.205. The transient appeared as a very blue object in Ep1 and quickly changed to green/yellow color in the following epochs. (middle two rows) D21 and D23 difference images that capture some of the characteristics of this transient. The location of the source is indicated by the red circle (0''.5 in radius) in each image. The change of color from blue to green/yellow is obvious in the D21 images, where its location shows negative signals in the three bluest bands and positive signals in the rest. It largely maintained the same color from Ep2 through Ep3 (although becoming dimmer) as seen in the D23 images. (bottom row) SED evolution over four epochs (left panel) and the light curves in the SW bands (middle) and the LW bands (right). In Ep1, this transient was invisible in the three reddest bands, and the downward arrows in its Ep1 SED indicate the 5 s upper limits in these bands (calculated on the error maps within 0''.165 radius circular aperture to best match the size within which the PSF fitting was done; see the Appendix). In F200W and the redder bands, the transient reached the maximum in Ep2 and then gradually faded