Examples of SDA Catalog Queries

Contents

• Introduction
• Query 1: Find all detected objects in the field of Abell 1689
• Query 2: Find all objects in HDF North and South having i < 27 and z < 24
• Query 3: Find all objects in HDF North and South having i-z > 2
• Query 4: Find all objects in SDA having BPZ > 6.0
• Query 5: Find all i-band dropouts within intermediate-redshift cluster fields
• Contact Information

Introduction

Version 1.10 of the SDA User Interface (UI) introduces unlimited photometric magnitude- and color-constrained queries of the object catalogs generated by APSIS. This enhancement allows the user to extract catalogued objects that satisfy complex photometric constraints completely within the SDA environment, thereby eliminating the need for subsequent catalog sifting by the user.

The introduction of the color-contrained-query capability forced a complete overhaul of the Structured Query Language (SQL) code that is generated and submitted to the SDA database server when a query is submitted through the UI. The complexity of the new code is presently accommodated by rigid rules of query construction, some of which are not intuitive to inexperienced users of the UI. This document provides examples of typical SDA queries that should assist users in constructing similar or more complex queries.

The UI presently processes SDA queries in a linear fashion with remedial hierarchical grouping. These limitations should not handicap most queries, but SDA development team recognizes that more flexibility is needed to enable the most complicated queries. Version 2.0 of the UI will allow users to group hierarchically blocks of logical expressions and to perform arithmetic operations on catalog parameters. In the meantime, the users should recognize and obey the following rules of query construction:

• The logical constraints within each category box in the UI's "Input parameters" tab are executed in linear fashion from top to bottom.
• Each category box is executed separately from the other boxes. Users may interpret this mode of execution as that expected when enclosing each category box within a single set of parentheses.
• The results of each category box are then concatenated or intersected with the results from any preceded boxes, depending on whether the logical "and" or "or" is selected between the boxes. This process is conducted in a linear fashion from top to bottom.
• Queries of the Photometry Catalog that are constrained by more than one filter and/or color must be constructed so that each filter or color constraint occupies a single category box. In other words, each category box should contain no more than one selected filter or color. Use separate category boxes joined with "and" or "or" to constrain searches by different filters or colors. Multiple constraints on the same filter or color, however, can be defined within a single category box.
• Queries of the Filter Catalog that are constrained by SExtractor parameters measured from more than one filter image must be constructed so that each filter occupies a single category box. In other words, each category box should contain parameters pertaining to no more than one selected filter. Use separate category boxes joined with "and" or "or" to constrain searches by parameters associated with different filter images. Multiple constraints on parameters pertaining to the same filter image, however, can be defined within a single category box.

Below are examples of SDA queries of increasing complexity. Each example is preceded by a description of the query. Clicking on an "Example" link will execute the query and take you to the UI's "Results" tab for that query. To inspect the construction of the input and output constraints for that query, simply click on the "Input parameters" or "Output parameters" tab above the tabulated results.

Query 1: Find all detected objects in the field of Abell 1689

This basic query allows one to retrieve all the objects detected by SExtractor in the latest APSIS run of the Abell 1689 dataset. The only input constraint is the SET_ID associated with the APSIS run. The SET_ID can be obtained from the Data Inventory. The user can download the object information from any combination of object catalogs (Detection, Filter, Photometry, and BPZ):

• Example 1: All parameters from Detection Catalog only
• Example 2: Selected parameters from Detection, Photometry, and BPZ catalogs

Query 2: Find all objects in HDF North and South having i < 27 and z < 24

This query searches two distinct datasets for objects having calibrated magnitudes of i < 27 and z < 24. Output parameters from the Detection Catalog (RA, Dec), Photometry Catalog (magnitudes and errors), and BPZ catalogs are requested.

• Example 3: Constrain query by extinction-corrected magnitudes; output only extinction-corrected magnitudes
• Example 4: Constrain query by uncorrected magnitudes; output uncorrected and corrected magnitudes

Query 3: Find all objects in HDF North and South having i-z > 2

This query searches the HDF datasets for objects having a calibrated color of i-z > 2. Subsequent color and magnitude constraints are added to isolate objects detected in both bands. Output parameters from the Detection Catalog (RA, Dec), Filter Catalog (MAG_ISO, MAG_AUTO), Photometry Catalog (magnitudes and errors), and BPZ catalogs are requested. Note that, presently, only extinction-corrected magnitudes are used in color-constrained queries.

• Example 5: Constrain color by lower bound only
• Example 6: Add i-z < 10 constraint to eliminate i-band dropouts
• Example 7: Add i < 28 constraint to isolate brightest objects

Query 4: Find all objects in SDA having BPZ > 6.0

Search the entire SDA (excluding "frozen" datasets 1, 4, 7, and 10) for all objects with Bayesian photometric redshifts greater than 6.0. Output parameters from the Detection Catalog (RA, Dec), Photometry Catalog (magnitudes and errors), and BPZ catalogs are requested.

• Example 8: As described above
• Example 9: Include only those objects imaged in F475W and other bands

Query 5: Find all i-band dropouts within intermediate-redshift cluster fields

The intermediate-redshift cluster CL0152-1357 was imaged in three bands (F625W, F775W, and F850LP), whereas the clusters CL1056-0337 and CL1252-2927 were imaged in two bands (F775W and F850LP). The three-band and two-band cases cannot yet be easily combined, so it is best to treat them separately at this time. When more sophisticated hierarchical grouping of query constraints is implemented in UI v2.0, collective analysis of these cases will be more easily implemented. The calibrated magnitude code for nondetections is 99. Output parameters from the Detection Catalog (RA, Dec, KRON_RADIUS), Photometry Catalog (magnitudes and errors), and BPZ catalogs are requested.

• Example 10: Search for i-band dropouts (F625W = 99 and F775W = 99) in three-band field CL0152-1357
• Example 11: Search for i-band dropouts (F775W = 99) in two-band fields CL1056-0337 and CL1252-2927

Contact Information