James Webb Space Telescope Feed Post

PEARLS: Near Infrared Photometry in the JWST North Ecliptic Pole Time Domain Field

Footprint of the imaging for different MMIRS filters in the NEP TDF using a ~23. ' 9×22. ' 6 Subaru HSC g, i2, z color composite as backdrop, with North up and East to the left with the grid showing coordinates in sexagesimal units. The NEP TDF is centered at (R.A., Decl.)J2000 = (17:22:47.896, +65:49:21.54). The white solid line outlines the Y imaging, the green dashed line outlines J, the thick blue dash-dotted line H, and the orange dots K. Most outlines overlap each other, with the exception of J. The K outline combines observations taken with the (short) K and Kspec filters; the latter occupy the SE corner quadrant. The figure also includes the outline of the completed JWST/NIRCam observations as a thin red solid line. When the MMIRS observations were initiated, a preliminary NEP TDF pointing and set of NIRCam position angles was used. The NIRCam observations as executed use a field center offset to the W, such that the full NEP TDF is covered with MMIRS only in J. Abstract: We present Near-Infrared (NIR) ground-based Y, J, H, and K imaging obtained in the James Webb Space Telescope North Ecliptic Pole Time Domain Field (TDF) using the MMT-Magellan Infrared Imager and Spectrometer (MMIRS) on the MMT.These new observations cover a field of approximately 230 arcmin^2 in Y, H, and K and 313 arcmin^2 in J. Using Monte Carlo simulations we estimate a 1 sigma depth relative to the background sky of (Y, J, H, K}) = (23.80, 23.53, 23.13, 23.28) in AB magnitudes for point sources at a 95% completeness level. These observations are part of the ground-based effort to characterize this region of the sky, supplementing space-based data obtained with Chandra, NuSTAR, XMM, AstroSat, HST, and JWST. This paper describes the observations and reduction of the NIR imaging and combines these NIR data with archival imaging in the visible, obtained with the Subaru Hyper-Suprime-Cam, to produce a merged catalog of 57,501 sources. The new observations reported here, plus the corresponding multi-wavelength catalog, will provide a baseline for time-domain studies of bright sources in the TDF.