Description of the ALMA Ceres Imaging and Spectrum bundle V1.0
==============================================================

Bundle Generation Date: 2022-07-11
Peer Review: 2022_Asteroid_Review
Discipline node: Small Bodies Node


Content description for the ALMA Ceres Imaging and Spectrum bundle
==================================================================

This archive package includes four data products: Calibrated Ceres Millimeter Images, Image Aspect Data, Ceres Millimeter Lightcurves, and Ceres Millimeter Spectrum.  These data products are based on raw ALMA data of three programs: 2015.1.01384.S, 2016.1.00748.S, and 2017.1.01640.S as archived in the ALMA Science Archive, corresponding to three observing epochs in October - November 2015, September 2017, and October 2017, respectively.  The detailed description of the keywords and the calibration process used to derive these data products can be found in Data_Description.pdf.

The Calibrated Ceres Millimeter Images product includes the 265 GHz images of Ceres collected by ALMA Band 6 in three epochs in October - November 2015, September 2017, and October 2017, with each epoch covering one full rotation of Ceres.  All image data are radiometrically calibrated to Jy/arcsec2.

The Image Description Data includes tabulated data in ASCII format that stores the observing time, beam characteristics, telescope pointing, and geometric parameters of Ceres for all images included in the Calibrated Ceres Images data product.

The Ceres Millimeter Lightcurves data product includes four lightcurves of Ceres extracted from the images in the Calibrated Ceres Images data product, and from the ALMA Compact Array (ACA) data collected in the October 2017 epoch, contemporaneously with the 12-meter array imaging data.  The image-based lightcurves were measured by integrating the flux over the whole disk of Ceres in the calibrated images (Li et al. 2020).  The derivation of flux from the ACA data is described in Data_Description.pdf.  The lightcurve data include the observation time and geometric parameters of Ceres for all data points.

The Ceres Millimeter Spectrum data product includes the raw spectrum of Ceres obtained by the ACA in the frequency range of 256.6360 - 266.1356 GHz in the October 2017 epoch.


Caveats to the data user
========================

For detailed information about possible issues and error analysis, please consult the data_description.pdfa.pdf file in the document directory.