IRSA Catalog Search Service:
Documentation for Web Interface:
Multi-Position Search

Overview

IRSA's Catalog Search Service allows users to search IRSA's catalogs using potentially complex constraints. The most common is a Spatial Constraint. The Multi-Position Search allows users to simultaneously perform cone searches on multiple positions specified in an uploaded table. This page describes how to specify a Multi-Position Search in the web version of IRSA's Catalog Search Service. You may also be interested in the following pages:

Upload Table

First choose "Multi-Object Search". Then click on the "Browse" button to upload a table that contains the following information in IPAC Table Format.

column name required? description units
ra required right ascension decimal degrees
dec required declination decimal degrees
major optional semi-major axis of elliptical cone search, or radius of circular cone search arcsec
ratio optional semi-minor axis divided by semi-major axis for elliptical cone search none
angle optional position angle of elliptical cone search degrees

Example 1:

Search a circular area around each of two positions.

First, make sure the radius box on the web interface is blank or "0". Next, create a table like this:

    \ EQUINOX = 'J2000.0'
    |   ra     |   dec    |  major |
    |   double |   double | double |
     185.500000  15.500000    1000.
     186.000000  15.000000     500.

Since there are is no column labeled ratio, the value under major is interpreted as the radius of a circular search.

Example 2:

Search an elliptical area around each of two positions.

First, make sure the radius box on the web interface is blank or "0". Next, create a table like this:

\ Example of ellipse search
\ EQUINOX = 'J2000.0'
|   ra     |   dec    |  major | ratio |
|   double |   double | double | double|
 185.500000 15.500000    1000.   0.25
 186.000000 15.000000     500.   0.50

Since there is no column labeled angle, the default position angle of zero is assumed.

Example 3:

Search an elliptical area around each of two positions, specifying the position angle.

First, make sure the radius box on the web interface is blank or "0". Next, create a table like this:

\ Example of ellipse search
\ EQUINOX = 'J2000.0'
|   ra     |   dec    |  major | ratio | angle |
|   double |   double | double | double| double|
 185.500000 15.500000    1000.    0.25    30
 186.000000 15.000000     500.    0.50    60

One to One Match

By default, all sources matching the query constraints (positional or otherwise) for a given input row will be returned in the output table. Conversely, if no sources match the query constraints for a given input row, then there will be no corresponding output rows. This can result in output tables which have a different number of rows than the input table. If the "One to One Match" box is checked, then the output table will have the same number of rows as the input table. If there are any objects that match the query constraints for a given input row, only the closest positional match will be returned in the output table. If no objects match the query constraints for a given input row, then the corresponding output row will be filled with nulls. The resulting table will be row-matched with the input table.

Cone Search Radius, PA, Axial Ratio

These parameters have the same meaning as they do for the Single Position Cone Search.

If you did not include the columns major, ratio, and angle in your input table, and you wish to have the same search parameters for every object in your input table, then you may specify these parameters once in the web interface.

Table Output

Assuming that you have chosen the Table Output option in the query building interface, then your output will be in IPAC Table Format.

Columns in the uploaded table will be included in the output table, with a suffix attached. This suffix will be "_01" unless the column name ends with "_NN" where NN is any integer from 01 to 98. In the latter case, the suffix will be incremented by one, to a maximum value of 99.