Querying the Catalog

The search pages are the beginning of the path for finding, reviewing, and downloading Chandra gratings data. There are several categories of search provided with parameters specific to that type of search. All search pages can be accessed at all time through the Query menu at the top left of your browser. There is also a "Quick search" option which tries to interpret your input, this option is available on the home page and via a menu item on most pages

Note that in all searches ( with the exception of "Derived Spectral Properties" ) the character "%" will match Zero or more characters ( numbers, symbols, letters ). In other words

722% will match 722,7220,7221,...,7228,7229
HD9312% will match HD93129 and HD93218 and HD93129A and HD93218B

In addition most searches allow the user to narrow down the results by limiting the detector and gratings to only certain combinations. This is typically useful when searching over a large coordinate area, or selecting on all obsids ( i.e. to find all ACIS/HETG observations ). These options can generally be ignored for other searches due to the limited number of gratings observations, see the trends page for more.

Target Name Search

Search by extraction target name(s), to search on more than a single name at a time enter each name separated by a new line.

During the V&V process the scientist verifies that automatic processing has identified the appropriate target for the extraction and ensures that the name matches the names stored in the TGCat database, which include: This search will return any TGCat source that has the given string within it, meaning that wildcards are implied at the begining and ending of the entry value. Additionaly any whitespace is both searched for and compressed, i.e. when in doubt include spaces

tau - will match "V* CM Tau" ( SIMBAD primary ID ) as well as "Proxima Centauri" and or course "tau CMa"
HD93129 - does not return any matches, while
HD 93129 - returns HD 93129AB

The TGCat name search provides the option to match the input to a SIMBAD identifier for the target. If the input is one of the SIMBAD Identifiers for a target, the coordinates of that target, as recorded in the SIMBAD catalog, will be passed back to TGCat to be matched within the "search radius" chosen. The following URL search is performed for each query:

http://simbad.u-strasbg.fr/simbad/sim-script?script=output%20console=off%20script=off %0a%20format%20object%20%22%25COO(d;A,D),%25IDLIST(1)%22%0aquery%20id%20{TARGET_NAME}

where {TARGET_NAME} is what the user has entered into the field.

An example of the output when searching for "crab":

http://simbad.u-strasbg.fr/simbad/sim-script?script=output%20console=off%20script=off %0a%20format%20object%20%22%25COO(d;A,D),%25IDLIST(1)%22%0aquery%20id%20crab :

083.63321,+22.01447,V* CM Tau

if using a 2 arcmin search radius ( default ), the TGCat database is then queried on

ra < 83.666543333333 and ra > 83.599876666667 and decl < 22.047803333333 and decl > 21.981136666667

Object Type Search

TGCat stores type information for each source it extracts. At present the only types stored are SIMBAD types, but there are plans for expanding this.

the "primary type" will always be the SIMBAD primary type.

to select more than one type in a single category press the Control button and select. The numbers that appear beside each type are the number of sources to which that type is assigned but does not reflect the number of objects with a particular type as their primary type. There are three types of type searches that can be done:

Coordinate Search

Coordinates can be entered in sexigessimal format or decimal format as per the following:

sexagessimal - 123:45:67.890 or 123 45 67.890 for RA and should be between 000:00:00.00 and 360:00:00.00
for DEC a "+" or "-" can be appended and values should be between -90:00:00.00 and +90:00:00.00
Decimal - 123.4567890 for RA and should be between 0.000 and 360.000
and (+/-)123.4567899 for DEC and should be between -90.000 and +90.000

All coordinates are Galactic J2000 epoch and in the IRCS frame

Spectral Properties Search

Search on derived spectral properties by specifying a min and max for each band/atom. See Flux Properties Summary for a description of these properties

Obsid Search

All Chandra Observations are marked with a unique ObsId which can be used to query for particular observations. This search has two options for specifying obsids:

Arbitrary Search

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