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PanSTARRS Follow-up Of K2 Campaign 16 and 17 Supernova Fields ("K2SNE")

Dotson et al. 2018, RNAAS, accepted

Introduction

Description of Data Products

Data Access

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Introduction

Since 2014, NASA's K2 mission has used the Kepler space telescope to perform high-precision photometry of tens of thousands of stars and galaxies along the ecliptic in "Campaigns" lasting between 65 and 80 days. Most Campaigns were executed in the "backward facing" direction, where the spacecraft was pointed roughly away from Earth. The advantage of this orientation, given Kepler's Earth-trailing orbit, is that Earth never crosses the field of view during a Campaign. However, in this orientation, the Campaign's field of view is only visible from the ground during twilight. K2's 16th and 17th Campaigns were in the "forward facing" orientation to facilitate contemporaneous observations from Earth-based facilities over the entire duration of the campaigns. Numerous investigations executed during C16 and C17 were designed to specifically take advantage of the ability to simultaneously obtain complementary observations of K2 targets. PanSTARRS1 ("PS1") monitored these fields during the K2 campaigns in multiple filters. The primary motivation was to identify supernovae in the K2 fields rapidly enough to enable follow-up observations. Transients were identified by the PanSTARRS Transient Science Server within 12-24 hours of observations. Alerts were released via the Transient Name Server. The PS1 K2 supernova survey data are released here as a MAST HLSP. Please refer to the AAS Research Note (Dotson et al. 2018) for more information and relevant references to the PanSTARRS data, observations, processing, and survey strategies. You can refer to the full collection of K2SNE data products using the DOI http://dx.doi.org/10.17909/T9CM3C.

Description of Data Products

Each cluster is organized into subdirectories based on the PS1 tessellation pattern, which is identical to the one used by the main PS1 survey. Each tessellation has multiple files with the following syntax:

hlsp_k2sne_ps1_gpc1_skycell.<skycellnum>-<mjd>_<filter>_v1_<exten>
where:
  • <skycellnum> = footprint identifier (e.g., "1014.030"), the first number is the "projection cell ID", the second number is the "skycell" indicating which part of the 10x10 grid this warp represents (1st number always 0, 2nd number is y-index, 3rd number is x-index), see the PS1 Tessellation Pattern Page for more info
  • <mjd> = Modified Julian Date of start of observation (e.g., "58220.420013")
  • <filt> = the filter used, one of "g", "r", "i", or "z"
  • <exteng> = file extension, which correspond to one of the following:
    • cmf.fits: camera-stage catalog file
    • log.txt: processing log file
    • mask.fits: mask file
    • mdl.fits: background model for the warp skycell image made up from the chip background models on a finer interpolated grid of the chip(s) that are remapped into the warp skycell image, it contains the background samples that can be interpolated to reconstruct the smooth background model that was subtracted from the science images
    • psf.fits: point spread function file
    • pswarp.fits: "MetaData Configuration" file (compressed text) file
    • stats.txt: text file containing pixel-level statistics on the skycell
    • wrp.fits: calibrated warp image
    • wt.fits: weight file

Distribution of K2SNE projection cells in the K2 Campaign 16 field.
Distribution of K2SNE projection cells in the K2 Campaign 17 field.

Data Access

There are three ways to download K2SNE data products:

  1. Produce cutouts using the K2SNE Web Cutout Tool.
  2. Use an API for programmatic access. An example Jupyter notebook can be found here.
  3. Download using links in the data table below, sorted by Projection ID. NOTE: Some of the .tar.gz files can be 100 GB in size.

Campaign 16
Projection Cell Approx. RA (deg.) Approx. Dec. (deg.) Skycell Bundle
1533 129.438202 ± 2.022472 +10.0 ± 2.0 Bundle (19.99 GB)
1534 133.483139 ± 2.022472 +10.0 ± 2.0 Bundle (27.87 GB)
1535 137.528091 ± 2.022472 +10.0 ± 2.0 Bundle (26.48 GB)
1622 130.909088 ± 2.045455 +14.0 ± 2.0 Bundle (266.57 GB)
1623 135.000000 ± 2.045455 +14.0 ± 2.0 Bundle (307.19 GB)
1624 139.090912 ± 2.045455 +14.0 ± 2.0 Bundle (172.63 GB)
1625 143.181808 ± 2.045455 +14.0 ± 2.0 Bundle (0.60 GB)
1708 125.581398 ± 2.093023 +18.0 ± 2.0 Bundle (0.72 GB)
1709 129.767441 ± 2.093023 +18.0 ± 2.0 Bundle (202.91 GB)
1710 133.953491 ± 2.093023 +18.0 ± 2.0 Bundle (278.03 GB)
1711 138.139542 ± 2.093023 +18.0 ± 2.0 Bundle (280.87 GB)
1712 142.325592 ± 2.093023 +18.0 ± 2.0 Bundle (53.98 GB)
1793 124.285713 ± 2.142857 +22.0 ± 2.0 Bundle (11.58 GB)
1794 128.571426 ± 2.142857 +22.0 ± 2.0 Bundle (186.53 GB)
1795 132.857132 ± 2.142857 +22.0 ± 2.0 Bundle (224.35 GB)
1796 137.142853 ± 2.142857 +22.0 ± 2.0 Bundle (252.73 GB)
1797 141.428574 ± 2.142857 +22.0 ± 2.0 Bundle (93.35 GB)
1877 127.317078 ± 2.195122 +26.0 ± 2.0 Bundle (6.69 GB)
1878 131.707321 ± 2.195122 +26.0 ± 2.0 Bundle (130.08 GB)
1879 136.097565 ± 2.195122 +26.0 ± 2.0 Bundle (124.41 GB)
1880 140.487808 ± 2.195122 +26.0 ± 2.0 Bundle (6.70 GB)
Campaign 17
Projection Cell Approx. RA (deg.) Approx. Dec. (deg.) Skycell Bundle
1014 196.363632 ± 2.045455 -14.0 ± 2.0 Bundle (20.57 GB)
1015 200.454544 ± 2.045455 -14.0 ± 2.0 Bundle (99.76 GB)
1016 204.545456 ± 2.045455 -14.0 ± 2.0 Bundle (94.70 GB)
1017 208.636353 ± 2.045455 -14.0 ± 2.0 Bundle (15.62 GB)
1103 198.202240 ± 2.022472 -10.0 ± 2.0 Bundle (84.53 GB)
1104 202.247192 ± 2.022472 -10.0 ± 2.0 Bundle (138.81 GB)
1105 206.292130 ± 2.022472 -10.0 ± 2.0 Bundle (160.58 GB)
1106 210.337082 ± 2.022472 -10.0 ± 2.0 Bundle (49.08 GB)
1191 194.157303 ± 2.022472 -6.0 ± 2.0 Bundle (3.81 GB)
1192 198.202240 ± 2.022472 -6.0 ± 2.0 Bundle (79.95 GB)
1193 202.247192 ± 2.022472 -6.0 ± 2.0 Bundle (132.64 GB)
1194 206.292130 ± 2.022472 -6.0 ± 2.0 Bundle (150.97 GB)
1195 210.337082 ± 2.022472 -6.0 ± 2.0 Bundle (63.32 GB)
1281 196.000000 ± 2.000000 -2.0 ± 2.0 Bundle (28.11 GB)
1282 200.000000 ± 2.000000 -2.0 ± 2.0 Bundle (89.69 GB)
1283 204.000000 ± 2.000000 -2.0 ± 2.0 Bundle (125.47 GB)
1284 208.000000 ± 2.000000 -2.0 ± 2.0 Bundle (46.53 GB)