Search the Chandra Source Catalog by OBS_ID
obsid_search_csc obsid outfile [columns] [download] [root] [bands] [filetype] [catalog] [verbose] [clobber]
'obsid_search_csc' uses the command line interface to the Chandra Source Catalog (CSC) to retrieve source properties and associated data products by Observation ID (obsid).
Users enter one or more OBS_ID values and the tool will query the CSC. The source properties results are written, one line per source, to a tab-separated-value (TSV) format output file, and when verbose is one or higher a subset of the data for each source is printed to the screen. The output file will contain a default set of catalog columns unless this is overridden with the 'columns' parameter. The data products associated with the sources may also be retrieved including the event files, response files (ARF, RMF, PSF, exposure map), and related histograms (spectra, lightcurves, images).
More complex queries including doing cross matches must be done using the CSCView application. Users whose research makes use of the Chandra Source Catalog should cite: Evans et al 2010, ApJS 189, 37.
unix% obsid_search_csc obsid=635 outfile=635.tsv download=none mode=h catalog=csc1
Search for all sources that were detected in OBS_ID 635.
obsid_search_csc obsid = 635 outfile = 635.tsv columns = INDEF download = none root = ./ bands = broad,wide filetypes = regevt,pha,arf,rmf,lc,psf,regexp catalog = csc1 verbose = 1 clobber = no mode = h 94 rows returned by query 94 Different Master Source(s). 1 Different Observation(s). name ra dec obsid CXO J162602.2-242348 246.50924 -24.39670 635 CXO J162603.1-242336 246.51290 -24.39352 635 CXO J162604.3-242252 246.51817 -24.38122 635 CXO J162605.8-242756 246.52432 -24.46570 635 ...
Returns a TSV format file with source list. The default set of columns returned are not printed to the screen but are saved in the TSV file.
% dmlist "635.tsv[opt kernel=text/tsv]" cols -------------------------------------------------------------------------------- Columns for Table Block 635.tsv -------------------------------------------------------------------------------- ColNo Name Unit Type Range 1 name String Source name in the format 'CXO Jhhmmss.s +/- ddmmss' 2 ra deg Real4 -Inf:+Inf Source position, ICRS right ascension 3 dec deg Real4 -Inf:+Inf Source position, ICRS declination 4 err_ellipse_r0 arcsec Real4 -Inf:+Inf Major radius of the 95% confidence level error ellipse 5 conf_flag String Source regions overlap (source is confused) 6 sat_src_flag String Source is saturated in all observations; source properties are unreliable 7 significance Real4 -Inf:+Inf Highest source flux significance across all observations ...
unix% obsid_search_csc 635,637 outfile=none download=ask filetype=evt columns=o.cnts_aper_b catalog=csc1
Search for two observations obsid=635 and 637. We have asked that the full field evt file be return but will be prompted (download=ask). Additionally we require the broad-band source counts for each observation.
obsid_search_csc obsid = 635,637 outfile = none columns = o.cnts_aper_b download = ask root = ./ bands = broad,wide filetypes = evt catalog = csc1 verbose = 1 clobber = no mode = ql 175 rows returned by query 152 Different Master Source(s). 2 Different Observation(s). name ra dec obsid cnts_aper_b CXO J162538.1-242235 246.40889 -24.37654 637 3569 CXO J162541.3-242138 246.42232 -24.35970 637 265 CXO J162552.5-241710 246.46882 -24.28632 637 149 ... CXO J162752.0-244049 246.96687 -24.68049 635 3849 CXO J162754.5-243717 246.97730 -24.62162 635 97 CXO J162755.2-242839 246.98017 -24.47765 635 91 If you use this data, please cite Evans et al 2010, ApJS 189, 37 Download data for CXO J162538.1-242235 in 00637_001 [y,n,a,q]: y Retrieving files for obsid_obi 00637_001 Retrieved file .//637/acisf00637_001N002_evt3.fits Download data for CXO J162541.3-242138 in 00637_001 [y,n,a,q]: a ...
When prompted for downloads: 'y' will retrieve the file and continue onto the next. 'n' will skip the current file and continue. 'a' will retrieve the remaining files with further prompting, and 'q' will skip the current file and will not retrieve nor prompt for any remaining files.
unix% obsid_search_csc @bootes.lis catalog=csc1
The list of observations can also be supplied using standard CIAO stacks.
Detailed Parameter Descriptions
Parameter=obsid (string required stacks=yes)
The OBS_ID number. Multiple obsid's may be input via a comma separated list or any other stack.
Parameter=outfile (file required)
Name of output table.
The output file name. If left blank or set to "none", the the table of source properties is not saved.
The output is the same Tab Separated Value (tsv) format as returned by CSCView. To use the file with DM tools users must explicitly specify the kernel:
unix% dmlist "mysrc.tsv[opt kernel=text/tsv]" cols -------------------------------------------------------------------------------- Columns for Table Block mysrc.tsv -------------------------------------------------------------------------------- ColNo Name Unit Type Range 1 name String Source name in the format 'CXO Jhhmmss.s +/- ddmmss' 2 ra String Source position, ICRS right ascension 3 dec String Source position, ICRS declination 4 err_ellipse_r0 arcsec Real4 -Inf:+Inf Major radius of the 95% confidence level error ellipse 5 conf_flag String Source regions overlap (source is confused) 6 sat_src_flag String Source is saturated; source properties are unreliable 7 significance Real4 -Inf:+Inf Highest source flux significance across all observations 8 flux_aper_b erg/s/cm^2 Real4 -Inf:+Inf Aperture-corrected net energy flux inferred from the source region aper ...
Parameter=columns (string not required default=INDEF stacks=yes)
The list of catalog columns to return.
The list of catalog columns to return. The default (INDEF) returns the list of columns returned by the combination of CSCView Master Summary and Obsid Summary defaults.
Several columns will be added to the query if they are not explicitly provided. These inlcude: m.name, m.ra, m.dec, o.instrument, o.obsid, o.obi, o.region_id, and a.match_type.
The prefix "m." or "o." should be used to specify the if the property is a Master Source property (ie a value derived from all individual observations) or an Obi Source property (computed from a single observation). The list of columns can also be input via a stack, eg columns=@my_favorite_cols.lis
The following special values may be used to return the standard set of columns defined by CSCView:
- "MSBS" , the set of Master Source Basic Summary columns
- "MSS", the set of Master Source Summary columns
- "MSP", the set of Master Source Photometry columns
- "MSV", the set of Master Source Variability columns
- "SOS", the set of Source Observation Summary columns
- "SOP", the set of Source Observation Photometry columns
- "SOV", the set of Source Observation Variability columns
The values are case-sensitive, and can be used with other values such as
unix% search_csc ... columns="SOS,a.match_type,o.livetime" ...
Parameter=download (string default=none)
Retrieve the associated data products?
Determine if data products should be retrieved. The valid options are
- "none" : no datasets are retrieved
- "ask" : ask for each master source if products should be retrieved.
- "all" : all products will be retrieved without asking
When asked, users have 4 choices
- y : yes to the current source
- n : no to the current source
- a : yes to the current source and all remaining sources
- q : no to the current source and all remaining sources
Parameter=root (file default=)
Output root directory for data products.
Parameter=bands (string default=broad,wide)
A comma separated list of energy bands
Various data products are stored in different energy bands.
- broad - ACIS 0.5 - 7.0 keV
- soft - ACIS 0.5 - 1.2 keV
- medium - ACIS 1.2 - 2.0 keV
- hard - ACIS 2.0 - 7.0
- ultrasoft - ACIS 0.2 - 0.5
- wide - HRC
This parameter is the list of energy bands for those products.
If bands is blank, all bands are retrieved.
Parameter=filetype (string default=regevt,pha,arf,rmf,lc,psf,regexp)
Comma separated list of file types to retrieve.
List of files to retrieve. The following list gives the valid options for catalog=csc1
- evt - Level 3 event file for entire observation
- exp - Full field exposure map (per energy band)
- ahst - Aspect histogram file
- bpix - Level 3 badpixel file
- fov - Level 3 field of view file
- bkgimg - Background image (per energy band)
- sens - Sensitivity map (per energy band)
- img - Exposure corrected, background subtracted full field image (per energy band)
- reg - Source region defintion
- arf - Auxillary Response File for spectral fitting
- rmf - Response Matrix File for spectral fitting
- pha - Spectrum
- regevt - Event file for just area around current source
- regexp - Region exposure map (per energy band)
- regimg - Exposure corrected image of source (per energy band)
- psf - Point Spread Function (per energy band)
- lc - Light curve (per energy band)
For catalog=csc2 the list of filetype values is
- evt - per observation event file
- asol - per observation aspect solution with astrometric corrections applied
- ahst - aspect histograms
- bpix - bad pixel file
- fov - field of view file
- pixmask - pixel mask file
- img - exposure corrected and background subtracted full field image
- bkgimg - background image
- exp - exposure maps
- poly - convex hull polygon regions
- regevt - per region, per observation event file
- pha - spectrum
- arf - Auxillary response file
- rmf - Response matrix
- reg - source region definitions
- regimg - image around source region
- psf - simulated PSF image
- regexp - exposure map around source region
- lc - lightcurve
- draws - MCMC random sample draws
- aperphot - aperture photometry results
- stkevt - merged event file for observations in detect stack
- stkfov - merged FOV file for detect stack
- stkecorrimg - detect stack exposure corrected image
- stkbkgimg - detect stack background image
- stkexpmap - exposure map for detect stack
- sensity - limiting sensitivity for detect stack
- stkregevt - merged detect stack event file around source region
- stksrcreg - source region for detect stack
- stkregimg - merged detect stack image around source region
- stkregexp - combined detect stack exposure map
- stkdraws - MCMC draws from combined detect stack photometry
- stkaperphot - photometry results for detect stack
- mrgsrc - master source properties tables
- bayesblks - Bayesian blocks definitions
- srcaperphot - master source aperture photometry
It is possible that the same file may be queued for retrieve more than once. The script will recognize this and will instead make a copy of the file instead of re-retrieving it from the archive.
The script will check if the file it is about to retrieve already exists. If so it will skip the and inform the user.
Files are place in subdirectories of the current directory. They are organized by OBS_ID, source name "CXOJ...", and then by region id. This heiarchry ensures that the large per-obi files are only retrieved/stored once per master source.
If filetype is left blank, all avialble file types are retrieved.
Parameter=catalog (string default=csc2)
Select which version of CSC catalog: csc1|csc2
Parameter=verbose (integer default=1 min=0 max=5)
Tool chatter level.
Parameter=clobber (boolean default=no)
Remove outfile if it already exists?
This only applies to outfile. Products are never overwritten.
Changes in the scripts 4.12.1 (December 2019) release
Change URLs to use the secure CXC web server.
Changes in the script 4.11.5 (October 2019) release
Version 2 of the Chandra Source Catalog has been officially released. The script has been updated to access csc2 by default. Users can access the previous version using catalog=csc1.
Changes in the scripts 4.11.2 (April 2019) release
Corrects logic introduced to fall back to using curl if CXC websites redirect to secure sites. User errors such as incorrect column names would not have been reported correctly.
Changes in the scripts 4.6.6 (September 2014) release
Corrects the "MSBS" (master source basic summary) macro.
Provide more information when CSC servers are down and the catalog is not available.
- Release 2 of Chandra Source Catalog not supported
This script does not support the current release 2 version of the Chandra Source Catalog.