TREASUREHUNT: Transients and Variability Discovered with HST in the JWST North Ecliptic Pole Time Domain Field

• DOI: 10.48550/arxiv.2401.04944
• Publication Date: 2024-01-01
• Authors: Rosalia O’Brien; Rolf A. Jansen; Norman A. Grogin; Seth H. Cohen; Brent M. Smith; R. Silver; W. Peter Maksym; Rogier A. Windhorst; Anton M. Koekemoer; Nimish P. Hathi; Christopher N. A....; Brenda Frye; Mehmet Alpaslan; M. L. N. Ashby; Teresa Ashcraft; Silvia Bonoli; W. Brisken; N. Cappelluti; F. Civano; Christopher J. Co...; V. S. Dhillon; Simon P. Driver; K. J. Duncan; Renato A. Dupke; M. Elvis; G. G. Fazio; Steven L. Finkels...; Hansung B. Gim; Alex Griffiths; Heidi B. Hammel; Minhee Hyun; Myungshin Im; Victoria Jones; D. Kim; B. Ladjelate; Rebecca L. Larson; Sangeeta Malhotra; Madeline A. Marshall; Stefanie N. Milam; J. D. R. Pierel; James E. Rhoads; S. Rodney; H. J. A. Röttgering; Michael J. Rutkowski; Jr. Ryan; M. J. Ward; C. W. White; R. J. van Weeren; X. Zhao; Jake Summers; J. C. J. D'Silva; Rafael Ortiz; A. S. G. Robotham; Dan Coe; M. Nonino; N. Pirzkal; Haojing Yan; T. Acharya
• Keywords: Ecliptic

The JWST North Ecliptic Pole (NEP) Time Domain Field (TDF) is a $>$14 arcmin diameter field optimized for multi-wavelength time-domain science with JWST. Its location within JWST's northern continuous viewing zone offers optimal conditions studies JWST, ensuring year-round observability, absence of bright stars, and minimal Zodiacal foreground interference. It has been observed across the electromagnetic spectrum both from ground space, including Hubble Space Telescope (HST). As part HST observations over 3 cycles (the "TREASUREHUNT" program), deep images were obtained ACS/WFC in F435W F606W that cover almost entire NEP TDF. Many individual pointings these programs partially overlap, allowing an initial assessment potential this cumulative area overlapping ~88 arcmin$^2$, time intervals between epochs range 1 day 4$+$ years. We present discovery 12 transients ~100 variable sources to depth $m_{\rm AB} \simeq$ 29.5 mag (F606W). majority will be supernovae, although at least two are likely quasars. Most AGN, where we find ~0.35% (0.04%) general $z < 6$ galaxy population vary 3$\sigma$ (5$\sigma$) level. Based on 5-year timeframe, translates into random supernova areal density up ~0.07 per arcmin$^2$ (~245 deg$^{-2}$) epoch, AGN ~1.4 variables (~5184 depths.