IRSA Image Server - SSA Queries

• Available data-sets
• Overview
• Metadata queries
• Query Constraints
• Examples
• Getting Help

Available data-sets

Spitzer Heritage Archive (SHA)
Data-set	Collection Name	Calibration Level
Spitzer Heritage Archive Public data taken before 02-Mar-2017	spitzer_sha	1, 2, and 3

Overview

An overview of how to perform SSA queries is provided below. For full details, please see the IVOA SSA specification.

Metadata queries

To perform a metadata query, visit /SSA?FORMAT=METADATA. The result will be a VOTable describing the image metadata columns that are returned by actual queries. All of IRSA's SSA datasets have been regularized and are contained in the same table.

Query Constraints

An SSA query returns a VOTable of images satisfying any number of constraints. By default, queries return results from all datasets. The complete list of parameters supported by IRSA's SSA implementation is:

• POS
• SIZE
• BAND
• TIME
• COLLECTION
• RESPONSEFORMAT
• FORMAT
• SPECRP
• PUBDID
• TARGETNAME
• TIMERES

POS

The POS parameter defines the center of the search region. The coordinate values must be specified as a comma-separated pair with no white space.

Coordinates default to right-ascension and declination in decimal degrees in the ICRS coordinate system.

Examples:

• POS=52,-27.8

SIZE

The POS parameter specifies the search region diameter in decimal degrees. A valid query does not have to specify a SIZE parameter. If SIZE is omitted in a positional query, the default value is 10 arcseconds.

Examples:

• SIZE=0.05

BAND

The BAND parameter specifies the desired wavelength range in units of meters.

If a single numerical value is specified, it matches any spectrum for which the spectral coverage includes the specified value.

If a range of wavelengths is given, a dataset matches if any portion of its spectral range overlaps the given spectral range. Ranges are specified as min/max.

Examples:

• BAND=10e-6
• BAND=8e-6/12e-6

TIME

The UTC value specified may be a single value or a range.

If a single value is specified it matches any dataset for which the time coverage includes the specified value.

If a two valued range is given, a dataset matches if any portion of it overlaps the given temporal region.

An imprecise value such as yyyy indicates the entire period specified, e.g., 1990-2000 would match any dataset overlapping the range from the beginning of 1990 to the end of 2000.

Examples:

• TIME=2013-0302T12:40:33
• TIME=2013-03-02
• TIME=2013-03
• TIME=2013

COLLECTION

The COLLECTION parameter identifies the group of data that an observation belongs to.

Examples:

• COLLECTION=spitzer_sha

RESPONSEFORMAT

The RESPONSEFORMAT parameter specifies what type of output the service will return. The default is VOTable, but many options are available:

• FITS: Flexible Image Transport System
• IPAC_TABLE: IPAC's Table Format
• HDF5: Hierarchical Data Format v5
• VOTABLE: IVOA VOTable
• JSON: JavaScript Object Notation
• CSV: Comma Separated Values (suitable for loading into spreadsheets)
• TSV: Tab Separated Values (suitable for loading into spreadsheets)
• TEXT: Plain text
• HTML: HTML table suitable for embedding within another page
• POSTGRES: SQL for loading the result into Postgres
• SQLITE: SQL for loading the result into SQLite
• ORACLE: SQL for loading the result into Oracle
• DB: Raw SQLite database

Examples:

• RESPONSEFORMAT=FITS
• RESPONSEFORMAT=JSON
• RESPONSEFORMAT=TEXT

Examples

1. Search for Spitzer spectra of the ULIRG Arp 220.

               curl -o example1.csv "https://irsa.ipac.caltech.edu/SSA?COLLECTION=spitzer_sha&RESPONSEFORMAT=csv&POS=233.738563,23.503139"

   Since we did not specify the size of the search region, the results (output into a comma-separated value file) will be include all spectral observations that are within 10 arcseconds of the specified position.

   Examining the search results, the target_name column indicates that all of these observations were meant to target Arp 220.

2. Widen the search radius a little, to about half a degree, to increase the likelihood of getting all the available spectra of Arp 220, as well as some sky observations.

               curl -o example2.csv "https://irsa.ipac.caltech.edu/SSA?COLLECTION=spitzer_sha&RESPONSEFORMAT=csv&POS=233.738563,23.503139&SIZE=0.5"

3. Only return spectra that cover the 9.7 micron silicate absorption feature at the redshift of Arp 220 (z = 0.018126).

               wget -O example3.csv "https://irsa.ipac.caltech.edu/SSA?COLLECTION=spitzer_sha&RESPONSEFORMAT=csv&POS=233.738563,23.503139&SIZE=0.5&BAND=8e-6/12e-6"

Getting Help

If you've run into a problem, think you've found a bug, or simply have questions, please contact IRSA User Support.