IV. NEOWISE Data Processing

IV.5. Archive Preparation

Contents

The NEOWISE archive is built upon the existing infrastructure established for WISE data products within the NASA/IPAC InfraRed Science Archive (IRSA). NEOWISE data are processed with the WISE Science Data System to generate Single-Exposure Images and the Single-Exposure Source Database (I.3). The Archive Preparation subsystem compiles source data, image data, and metadata (data about the data) from the processing pipeline, generates additional columns in the data structures that are not standard pipeline products, and outputs the combined data in Single-Exposure Source and Metadata files that are readable by the database loading system created by IRSA.

All data are prepared as described in section IV.7 of the WISE All-Sky Release Explanatory Supplement. The following highlights the new columns in the NEOWISE tables.

IV.5.a. NEOWISE Single-exposure Source Database

Column descriptions for the NEOWISE Single-exposure Source Database are found in section II.1.a.

The following columns were added to the Single-exposure Source Database for NEOWISE.

• NEOWISE Sources have AllWISE Source Catalog Associations in addition to the 2MASS PSC Associations.
  
  
  • allwise_cntr - AllWISE Source Catalog association. Unique identifier of the closest source in the AllWISE Source Catalog that falls within 3" of the position of this NEOWISE source. This is equivalent to the cntr in the AllWISE Catalog entry.
  
  
  • r_allwise - Distance separating the positions of the NEOWISE source and associated AllWISE Catalog source within 3".
  
  
  • pa_allwise - Position angle (degrees E of N) of the vector from the NEOWISE source to the associated AllWISE Catalog source.
  
  
  • n_allwise - The number of AllWISE Catalog entries found within a 3" radius of the NEOWISE source position.
  
  
  • w1mpro_allwise - W1 profile-fit magnitude or magnitude upper limit of the associated AllWISE Catalog source.
  
  
  • w1sigmpro_allwise - w1 profile-fit photometric uncertainty of the associated AllWISE Catalog source.
  
  
  • w2mpro_allwise - W2 profile-fit magnitude or magnitude upper limit of the associated AllWISE Catalog source.
  
  
  • w2sigmpro_allwise - w2 profile-fit photometric uncertainty of the associated AllWISE Catalog source.
  
  
  • w3mpro_allwise - W3 profile-fit magnitude or magnitude upper limit of the associated AllWISE Catalog source.
  
  
  • w3sigmpro_allwise - w3 profile-fit photometric uncertainty of the associated AllWISE Catalog source.
  
  
  • w4mpro_allwise - W4 profile-fit magnitude or magnitude upper limit of the associated AllWISE Catalog source.
  
  
  • w4sigmpro_allwise - w4 profile-fit photometric uncertainty of the associated AllWISE Catalog source.
  
  
• w1fitr, w2fitr - Profile-fit photometry fitting radius. This is the radius of the circular region used in the PSF-fitting flux and position measurement process. As described in IV.4.c.iii of the WISE All-Sky Release Explanatory Supplement, the fitting radius is 7.5 arcsec for non-saturated W1 candidate detections, which is approximately 1.25*FWHM of the PSF. In the case of saturated sources, the fitting radius is enlarged to approximately two times the radius of the saturated source core.


• xscprox - Distance separating the NEOWISE sources and a 2MASS Extended Source Catalog (XSC) source, if the separation is less than 1.1 times the Ks isophotal radius size of the XSC source. This identifies NEOWISE detections that are identically the 2MASS XSC source as well as NEOWISE detections that are fragments of large galaxies.


• Spatial Index htm20 - Level 20 HTM Spatial Index Key for faster database retrieval. A level 20 Hierarchical Triangular Mesh position index, computed from the unit sphere coordinates, in decimal format. Sources with the same spatial index value are close to each other on the sky. Level 20 provides a finer resolution for indexing than Level 7, used in former WISE releases, resulting in faster retrieval rates.

IV.5.b. NEOWISE Single-exposure Frame Metadata

Column descriptions for the NEOWISE Single-exposure Frame Metadata Table are found in Section III.1.c.

The following columns were added to the Single-exposure Frame Metadata Database for NEOWISE.

• Image metrics built from the composite W1 PSFs
  
  • r_major - major axis, in units of resampled pixels
  • r_phi - position angle, measured counterclockwise from the y-axis
  • r_01p - semi-major axis of the 0.1 points
  • r_05p - semi-major axis of the half-power points
  • bovera - axis ratio of the 0.1 points


• Payload Temperatures
  
  • bsplmout - [K] Beamsplitter Mount Temperature
  • telintft - [K] Telescope Interface Flange Temperature


• Spatial Index htm20 - Level 20 HTM Spatial Index Key for faster database retrieval. A level 20 Hierarchical Triangular Mesh position index, computed from the unit sphere coordinates, in decimal format. Sources with the same spatial index value are close to each other on the sky. Level 20 provides a finer resolution for indexing than Level 7, used in former WISE releases, resulting in faster retrieval rates.

Last update: 9 February 2024