Description of the 2MASS ASTEROID AND COMET SURVEY bundle V1.0 ============================================================== Bundle Generation Date: 2020-02-28 Peer Review: 2010 Asteroid Review, Mon Jun 07 00:00:00 MST 2010 Discipline node: Small Bodies Node Content description based on the data set catalog file description for the PDS3 version, EAR-A-I0054/I0055-5-2MASS-V2.0 ======================================================================================================================= Note: for PDS3 data sets migrated to PDS4, the following text is taken verbatim from the data set description and confidence level note of the PDS3 data set catalog file. In these cases, some details may not be correct as a description of the PDS4 bundle. The Two-Micron All-Sky Survey (2MASS) carried out a survey of the entire sky at J (1.25 microns), H (1.65 microns), and Ks (2.17 microns) during the years 1997-2001. The survey was conducted by two nearly identical telescopes and instruments, one at the Whipple Observatory on Mt. Hopkins, in Arizona, and one at the Cerro Tololo Interamerican Observatory on Cerro Tololo in Chile. A single data processing pipeline was used for the entire survey. The All-Sky Point Source Catalog (PSC), released in March 2003, contains photometry and astrometry for 470,999,970 sources, of which 16,028 were positionally associated with known solar system bodies including asteroids, comets, planets, and planetary satellites. The JHKs photometry for these sources, with their associations, were released as the original 2MASS Asteroid and Comet Survey, V1.0 of this data set. The 2MASS Extended Mission extended the survey by the inclusion of additional source extractions which were not selected for the original PSC because they were either a) unused duplicate detections of sources in the overlapping regions between tiles, b) too faint to meet the catalog standards for completeness and reliability, or c) identified as detections of image artifacts with a probability that would compromise catalog reliability. The overall reliability of these additional source extractions is much lower than that of the All-Sky Release, and they are not a uniform representation of the near infrared sky. The Extended Mission also added two new databases of detections, the Long Exposure (6x) Extracted Source Database, and the Calibration Extracted Source Database. The 6x database contains extracted sources from scans taken at six times the normal Survey exposure time to probe ~1 magnitude deeper than the nominal Survey. These observations cover approximately 590 square degrees on selected astronomical targets. The Calibration database contains sources extracted from the scans of the 35 primary calibration fields which were used to derive the nightly photometric calibration transformations. Version 2.0 of this data set contains all the sources in the original release plus additional source extractions from the Survey, from the 6x extracted source database, and from the Calibration extracted source database. Orbital elements used to predict the positions of the asteroids, comets, planets, and satellites is given in the data files in the form of p and q position vectors. Plots of the filter profiles of the J, H, and Ks filters are included in the document directory. Detection of unknown solar system bodies in the 2MASS data is technically possible, but has not been carried out for this data set. Please include the following attribution in any published material that makes use of any 2MASS image or tabular data: 'This publication makes use of data products from the Two Micron All Sky Survey, which is a joint project of the University of Massachusetts and the Infrared Processing and Analysis Center/California Institute of Technology, funded by the National Aeronautics and Space Administration and the National Science Foundation.' Further documentation of the 2MASS survey can be found at: Cutri, R.M., et al. 2004. Explanatory Supplement to the 2MASS All Sky Data Release. http://www.ipac.caltech.edu/2mass/releases/allsky/doc. (included on the 'extras' subdirectory of this volume) Sykes, M.V., R.M. Cutri, J.W. Fowler, D.J. Tholen, M.F. Skrutskie, S. Price, and E.F. Tedesco 2000. The 2MASS asteroid and comet survey. Icarus 146, 161-175. Known issues or problems with the data ====================================== Association between predicted solar system objects and 2MASS source positions does not imply a physical identification. An estimate of the reliability of the 2MASS source extraction for a given source may be found in the RELIABILITY_FLAG given in the data tables. Sources derived from the 2MASS Extended Mission Ancillary Products have not received the same level of validation and scrutiny as the All-Sky Release sources. The data base from which each individual source in the data tables has been derived can be determined from the DS_ORIGIN flag given in the tables. Because the association of asteroid positions and 2MASS sources is blind, there is always the chance of association with background astrophysical sources, particularly at low galactic latitudes. Stars near the galactic plane will tend to be reddened by foreground dust, giving rise to a redward spike in the (J-H) (H-Ks) color-color plot. Contamination from galactic stars in the 2MASS asteroid associations is shown by such a redward spike in the color-color plot of the asteroid associations. For further discussion of the contamination problem, see [SYKESETAL2002]: Sykes, M.V., R.M. Cutri, J.M. Fowler, B. Nelson, D.J. Tholen, M.F. Skrutskie, and S. Price, 2MASS observations of the solar system, in the Proceedings of Asteroids, Comets, Meteors (ACM 2002), Technical University Berlin, Berlin, Germany, pp. 484-484, 2002. The confidence level of the positional association of sources with solar system bodies and of the photometric and astrometric measurements is indicated by flags within the data tables. These flags are defined in the file flagdef.txt in the document directory of the data set. PDS3 Source =========== Version 1.0 of this bundle was migrated from version 2.0 of the PDS3 data set EAR-A-I0054/I0055-5-2MASS-V2.0.