Simple Command Line Access to the Chandra Source Catalog
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CIAO 4.18 Science Threads
Overview
Synopsis:
The Chandra Source Catalog (CSC) version 2.2 contains properties for around 430,000 point-like sources observed by Chandra up to the end of 2023. This includes source positions, fluxes, count rates, hardness ratios (colors), extent, and measures of variability in multiple energy bands; all of which are reported for each individual observation as well as merged properties for overlapping datasets.
The primary interface to query the source catalog is CSCView a Java-based graphical user interface (GUI). There is also a web based command line interface (CLI) that is available for users who experience problems running the Java application.
The CIAO contributed scripts search_csc and obsid_search_csc provide simple wrappers around the CLI interface for the two most common and simple searches: a radius search around a position and a search by a Chandra OBS_ID
Purpose:
To show how to perform a simple search of the CSC catalog using either a Chandra OBS_ID or a position with radius.
Users who require more filtering and sorting capabilities should use the CSCView application.
Related Links:
- For details on the Chandra Source Catalog, the properties, and data products, users should visit the Chandra Source Catalog web site.
Last Update: 8 Oct 2026 - Updated for the CSC 2.2 release (use cat=latest). Added an example of using the prism support in DS9 to display the TSV file, and updating the Limiting Sensitivity section.
Contents
- Getting Started
- Search by Position
- Search by OBS_ID
- Retrieve Data Products
- Using results with CIAO
- Upper Limits
- More options?
- History
- Images
Getting Started
To get started will assume that a user knows the position or name of a source of interest. As an example we will use the source
SDSS J1004+4112
from the Sload Digitial Sky Survey catalog.
Search by Position
We begin our search by simply using the search_csc script and providing the name of the object and a search radius (in the default units of arc-minutes). Since the name has a space it needs to be quoted.
The search_csc and obsid_search_csc scripts both use the version parameter to determine the catalog to query. With the release of 2.2 CSC the only way to access the latest data is to set the parameter to catalog=latest.
unix% search_csc "SDSS J1004+4112" radius=1 outfile=none cat=latest
search_csc
pos = SDSS J1004+4112
radius = 1
outfile = none
radunit = arcmin
columns = INDEF
sensitivity = no
download = none
root = ./
bands = broad,wide
filetypes = regevt,pha,arf,rmf,lc,psf,regexp
catalog = latest
verbose = 1
clobber = no
mode = ql
185 rows returned by query
11 Different Master Source(s).
17 Different Observation(s).
name ra dec sepn obsid
2CXO J100430.8+411208 1.511285e+02 4.120248e+01 0.95' 5794
2CXO J100430.8+411208 1.511285e+02 4.120248e+01 0.95' 19635
2CXO J100430.8+411208 1.511285e+02 4.120248e+01 0.95' 11546
2CXO J100430.8+411208 1.511285e+02 4.120248e+01 0.95' 11547
2CXO J100430.8+411208 1.511285e+02 4.120248e+01 0.95' 11548
2CXO J100430.8+411208 1.511285e+02 4.120248e+01 0.95' 11549
2CXO J100430.8+411208 1.511285e+02 4.120248e+01 0.95' 14495
2CXO J100430.8+411208 1.511285e+02 4.120248e+01 0.95' 14496
2CXO J100430.8+411208 1.511285e+02 4.120248e+01 0.95' 14497
2CXO J100430.8+411208 1.511285e+02 4.120248e+01 0.95' 14498
2CXO J100430.8+411208 1.511285e+02 4.120248e+01 0.95' 14499
2CXO J100430.8+411208 1.511285e+02 4.120248e+01 0.95' 14500
2CXO J100430.8+411208 1.511285e+02 4.120248e+01 0.95' 19632
2CXO J100430.8+411208 1.511285e+02 4.120248e+01 0.95' 19633
2CXO J100430.8+411208 1.511285e+02 4.120248e+01 0.95' 19634
2CXO J100430.8+411208 1.511285e+02 4.120248e+01 0.95' 19636
2CXO J100430.8+411208 1.511285e+02 4.120248e+01 0.95' 19637
2CXO J100433.6+411307 1.511403e+02 4.121864e+01 0.47' 5794
2CXO J100433.6+411307 1.511403e+02 4.121864e+01 0.47' 19635
2CXO J100433.6+411307 1.511403e+02 4.121864e+01 0.47' 11546
2CXO J100433.6+411307 1.511403e+02 4.121864e+01 0.47' 11547
2CXO J100433.6+411307 1.511403e+02 4.121864e+01 0.47' 11548
2CXO J100433.6+411307 1.511403e+02 4.121864e+01 0.47' 11549
2CXO J100433.6+411307 1.511403e+02 4.121864e+01 0.47' 14495
2CXO J100433.6+411307 1.511403e+02 4.121864e+01 0.47' 14496
2CXO J100433.6+411307 1.511403e+02 4.121864e+01 0.47' 14497
2CXO J100433.6+411307 1.511403e+02 4.121864e+01 0.47' 14498
2CXO J100433.6+411307 1.511403e+02 4.121864e+01 0.47' 14499
2CXO J100433.6+411307 1.511403e+02 4.121864e+01 0.47' 14500
2CXO J100433.6+411307 1.511403e+02 4.121864e+01 0.47' 19632
2CXO J100433.6+411307 1.511403e+02 4.121864e+01 0.47' 19633
2CXO J100433.6+411307 1.511403e+02 4.121864e+01 0.47' 19634
2CXO J100433.6+411307 1.511403e+02 4.121864e+01 0.47' 19636
2CXO J100433.6+411307 1.511403e+02 4.121864e+01 0.47' 19637
2CXO J100433.8+411234 1.511409e+02 4.120963e+01 0.25' 5794
2CXO J100433.8+411234 1.511409e+02 4.120963e+01 0.25' 19635
2CXO J100433.8+411234 1.511409e+02 4.120963e+01 0.25' 11546
2CXO J100433.8+411234 1.511409e+02 4.120963e+01 0.25' 11547
2CXO J100433.8+411234 1.511409e+02 4.120963e+01 0.25' 11548
2CXO J100433.8+411234 1.511409e+02 4.120963e+01 0.25' 11549
2CXO J100433.8+411234 1.511409e+02 4.120963e+01 0.25' 14495
2CXO J100433.8+411234 1.511409e+02 4.120963e+01 0.25' 14496
2CXO J100433.8+411234 1.511409e+02 4.120963e+01 0.25' 14497
2CXO J100433.8+411234 1.511409e+02 4.120963e+01 0.25' 14498
2CXO J100433.8+411234 1.511409e+02 4.120963e+01 0.25' 14499
2CXO J100433.8+411234 1.511409e+02 4.120963e+01 0.25' 14500
2CXO J100433.8+411234 1.511409e+02 4.120963e+01 0.25' 19632
2CXO J100433.8+411234 1.511409e+02 4.120963e+01 0.25' 19633
2CXO J100433.8+411234 1.511409e+02 4.120963e+01 0.25' 19634
2CXO J100433.8+411234 1.511409e+02 4.120963e+01 0.25' 19636
2CXO J100433.8+411234 1.511409e+02 4.120963e+01 0.25' 19637
2CXO J100434.0+411248 1.511419e+02 4.121357e+01 0.2' 5794
2CXO J100434.0+411248 1.511419e+02 4.121357e+01 0.2' 19635
2CXO J100434.0+411248 1.511419e+02 4.121357e+01 0.2' 11546
2CXO J100434.0+411248 1.511419e+02 4.121357e+01 0.2' 11547
2CXO J100434.0+411248 1.511419e+02 4.121357e+01 0.2' 11548
2CXO J100434.0+411248 1.511419e+02 4.121357e+01 0.2' 11549
2CXO J100434.0+411248 1.511419e+02 4.121357e+01 0.2' 14495
2CXO J100434.0+411248 1.511419e+02 4.121357e+01 0.2' 14496
2CXO J100434.0+411248 1.511419e+02 4.121357e+01 0.2' 14497
2CXO J100434.0+411248 1.511419e+02 4.121357e+01 0.2' 14498
2CXO J100434.0+411248 1.511419e+02 4.121357e+01 0.2' 14499
2CXO J100434.0+411248 1.511419e+02 4.121357e+01 0.2' 14500
2CXO J100434.0+411248 1.511419e+02 4.121357e+01 0.2' 19632
2CXO J100434.0+411248 1.511419e+02 4.121357e+01 0.2' 19633
2CXO J100434.0+411248 1.511419e+02 4.121357e+01 0.2' 19634
2CXO J100434.0+411248 1.511419e+02 4.121357e+01 0.2' 19636
2CXO J100434.0+411248 1.511419e+02 4.121357e+01 0.2' 19637
2CXO J100434.1+411243 1.511424e+02 4.121217e+01 0.14' 5794
2CXO J100434.1+411243 1.511424e+02 4.121217e+01 0.14' 19635
2CXO J100434.1+411243 1.511424e+02 4.121217e+01 0.14' 11546
2CXO J100434.1+411243 1.511424e+02 4.121217e+01 0.14' 11547
2CXO J100434.1+411243 1.511424e+02 4.121217e+01 0.14' 11548
2CXO J100434.1+411243 1.511424e+02 4.121217e+01 0.14' 11549
2CXO J100434.1+411243 1.511424e+02 4.121217e+01 0.14' 14495
2CXO J100434.1+411243 1.511424e+02 4.121217e+01 0.14' 14496
2CXO J100434.1+411243 1.511424e+02 4.121217e+01 0.14' 14497
2CXO J100434.1+411243 1.511424e+02 4.121217e+01 0.14' 14498
2CXO J100434.1+411243 1.511424e+02 4.121217e+01 0.14' 14499
2CXO J100434.1+411243 1.511424e+02 4.121217e+01 0.14' 14500
2CXO J100434.1+411243 1.511424e+02 4.121217e+01 0.14' 19632
2CXO J100434.1+411243 1.511424e+02 4.121217e+01 0.14' 19633
2CXO J100434.1+411243 1.511424e+02 4.121217e+01 0.14' 19634
2CXO J100434.1+411243 1.511424e+02 4.121217e+01 0.14' 19636
2CXO J100434.1+411243 1.511424e+02 4.121217e+01 0.14' 19637
2CXO J100434.2+411220 1.511428e+02 4.120560e+01 0.4' 5794
2CXO J100434.2+411220 1.511428e+02 4.120560e+01 0.4' 19635
2CXO J100434.2+411220 1.511428e+02 4.120560e+01 0.4' 11546
2CXO J100434.2+411220 1.511428e+02 4.120560e+01 0.4' 11547
2CXO J100434.2+411220 1.511428e+02 4.120560e+01 0.4' 11548
2CXO J100434.2+411220 1.511428e+02 4.120560e+01 0.4' 11549
2CXO J100434.2+411220 1.511428e+02 4.120560e+01 0.4' 14495
2CXO J100434.2+411220 1.511428e+02 4.120560e+01 0.4' 14496
2CXO J100434.2+411220 1.511428e+02 4.120560e+01 0.4' 14497
2CXO J100434.2+411220 1.511428e+02 4.120560e+01 0.4' 14498
2CXO J100434.2+411220 1.511428e+02 4.120560e+01 0.4' 14499
2CXO J100434.2+411220 1.511428e+02 4.120560e+01 0.4' 14500
2CXO J100434.2+411220 1.511428e+02 4.120560e+01 0.4' 19632
2CXO J100434.2+411220 1.511428e+02 4.120560e+01 0.4' 19633
2CXO J100434.2+411220 1.511428e+02 4.120560e+01 0.4' 19634
2CXO J100434.2+411220 1.511428e+02 4.120560e+01 0.4' 19636
2CXO J100434.2+411220 1.511428e+02 4.120560e+01 0.4' 19637
2CXO J100434.2+411242X 1.511421e+02 4.121243e+01 0.16' 11546
2CXO J100434.2+411242X 1.511421e+02 4.121243e+01 0.16' 11547
2CXO J100434.2+411242X 1.511421e+02 4.121243e+01 0.16' 11548
2CXO J100434.2+411242X 1.511421e+02 4.121243e+01 0.16' 11549
2CXO J100434.2+411242X 1.511421e+02 4.121243e+01 0.16' 14495
2CXO J100434.2+411242X 1.511421e+02 4.121243e+01 0.16' 14496
2CXO J100434.2+411242X 1.511421e+02 4.121243e+01 0.16' 14497
2CXO J100434.2+411242X 1.511421e+02 4.121243e+01 0.16' 14498
2CXO J100434.2+411242X 1.511421e+02 4.121243e+01 0.16' 14499
2CXO J100434.2+411242X 1.511421e+02 4.121243e+01 0.16' 14500
2CXO J100434.2+411242X 1.511421e+02 4.121243e+01 0.16' 19632
2CXO J100434.2+411242X 1.511421e+02 4.121243e+01 0.16' 19633
2CXO J100434.2+411242X 1.511421e+02 4.121243e+01 0.16' 19634
2CXO J100434.2+411242X 1.511421e+02 4.121243e+01 0.16' 19636
2CXO J100434.2+411242X 1.511421e+02 4.121243e+01 0.16' 19637
2CXO J100434.8+411239 1.511450e+02 4.121087e+01 0.064' 5794
2CXO J100434.8+411239 1.511450e+02 4.121087e+01 0.064' 19635
2CXO J100434.8+411239 1.511450e+02 4.121087e+01 0.064' 11546
2CXO J100434.8+411239 1.511450e+02 4.121087e+01 0.064' 11547
2CXO J100434.8+411239 1.511450e+02 4.121087e+01 0.064' 11548
2CXO J100434.8+411239 1.511450e+02 4.121087e+01 0.064' 11549
2CXO J100434.8+411239 1.511450e+02 4.121087e+01 0.064' 14495
2CXO J100434.8+411239 1.511450e+02 4.121087e+01 0.064' 14496
2CXO J100434.8+411239 1.511450e+02 4.121087e+01 0.064' 14497
2CXO J100434.8+411239 1.511450e+02 4.121087e+01 0.064' 14498
2CXO J100434.8+411239 1.511450e+02 4.121087e+01 0.064' 14499
2CXO J100434.8+411239 1.511450e+02 4.121087e+01 0.064' 14500
2CXO J100434.8+411239 1.511450e+02 4.121087e+01 0.064' 19632
2CXO J100434.8+411239 1.511450e+02 4.121087e+01 0.064' 19633
2CXO J100434.8+411239 1.511450e+02 4.121087e+01 0.064' 19634
2CXO J100434.8+411239 1.511450e+02 4.121087e+01 0.064' 19636
2CXO J100434.8+411239 1.511450e+02 4.121087e+01 0.064' 19637
2CXO J100434.9+411242 1.511455e+02 4.121186e+01 0.0036' 5794
2CXO J100434.9+411242 1.511455e+02 4.121186e+01 0.0036' 19635
2CXO J100434.9+411242 1.511455e+02 4.121186e+01 0.0036' 11546
2CXO J100434.9+411242 1.511455e+02 4.121186e+01 0.0036' 11547
2CXO J100434.9+411242 1.511455e+02 4.121186e+01 0.0036' 11548
2CXO J100434.9+411242 1.511455e+02 4.121186e+01 0.0036' 11549
2CXO J100434.9+411242 1.511455e+02 4.121186e+01 0.0036' 14495
2CXO J100434.9+411242 1.511455e+02 4.121186e+01 0.0036' 14496
2CXO J100434.9+411242 1.511455e+02 4.121186e+01 0.0036' 14497
2CXO J100434.9+411242 1.511455e+02 4.121186e+01 0.0036' 14498
2CXO J100434.9+411242 1.511455e+02 4.121186e+01 0.0036' 14499
2CXO J100434.9+411242 1.511455e+02 4.121186e+01 0.0036' 14500
2CXO J100434.9+411242 1.511455e+02 4.121186e+01 0.0036' 19632
2CXO J100434.9+411242 1.511455e+02 4.121186e+01 0.0036' 19633
2CXO J100434.9+411242 1.511455e+02 4.121186e+01 0.0036' 19634
2CXO J100434.9+411242 1.511455e+02 4.121186e+01 0.0036' 19636
2CXO J100434.9+411242 1.511455e+02 4.121186e+01 0.0036' 19637
2CXO J100437.1+411231 1.511548e+02 4.120886e+01 0.45' 5794
2CXO J100437.1+411231 1.511548e+02 4.120886e+01 0.45' 19635
2CXO J100437.1+411231 1.511548e+02 4.120886e+01 0.45' 11546
2CXO J100437.1+411231 1.511548e+02 4.120886e+01 0.45' 11547
2CXO J100437.1+411231 1.511548e+02 4.120886e+01 0.45' 11548
2CXO J100437.1+411231 1.511548e+02 4.120886e+01 0.45' 11549
2CXO J100437.1+411231 1.511548e+02 4.120886e+01 0.45' 14495
2CXO J100437.1+411231 1.511548e+02 4.120886e+01 0.45' 14496
2CXO J100437.1+411231 1.511548e+02 4.120886e+01 0.45' 14497
2CXO J100437.1+411231 1.511548e+02 4.120886e+01 0.45' 14498
2CXO J100437.1+411231 1.511548e+02 4.120886e+01 0.45' 14499
2CXO J100437.1+411231 1.511548e+02 4.120886e+01 0.45' 14500
2CXO J100437.1+411231 1.511548e+02 4.120886e+01 0.45' 19632
2CXO J100437.1+411231 1.511548e+02 4.120886e+01 0.45' 19633
2CXO J100437.1+411231 1.511548e+02 4.120886e+01 0.45' 19634
2CXO J100437.1+411231 1.511548e+02 4.120886e+01 0.45' 19636
2CXO J100437.1+411231 1.511548e+02 4.120886e+01 0.45' 19637
2CXO J100438.7+411249 1.511613e+02 4.121383e+01 0.72' 5794
2CXO J100438.7+411249 1.511613e+02 4.121383e+01 0.72' 19635
2CXO J100438.7+411249 1.511613e+02 4.121383e+01 0.72' 11546
2CXO J100438.7+411249 1.511613e+02 4.121383e+01 0.72' 11547
2CXO J100438.7+411249 1.511613e+02 4.121383e+01 0.72' 11548
2CXO J100438.7+411249 1.511613e+02 4.121383e+01 0.72' 11549
2CXO J100438.7+411249 1.511613e+02 4.121383e+01 0.72' 14495
2CXO J100438.7+411249 1.511613e+02 4.121383e+01 0.72' 14496
2CXO J100438.7+411249 1.511613e+02 4.121383e+01 0.72' 14497
2CXO J100438.7+411249 1.511613e+02 4.121383e+01 0.72' 14498
2CXO J100438.7+411249 1.511613e+02 4.121383e+01 0.72' 14499
2CXO J100438.7+411249 1.511613e+02 4.121383e+01 0.72' 14500
2CXO J100438.7+411249 1.511613e+02 4.121383e+01 0.72' 19632
2CXO J100438.7+411249 1.511613e+02 4.121383e+01 0.72' 19633
2CXO J100438.7+411249 1.511613e+02 4.121383e+01 0.72' 19634
2CXO J100438.7+411249 1.511613e+02 4.121383e+01 0.72' 19636
2CXO J100438.7+411249 1.511613e+02 4.121383e+01 0.72' 19637
The results are printed to the screen. There are 11 sources in the CSC within 1 arcmin of the location SDSS J1004+4112. Note that there are more than 11 lines reported in the output of search_csc since each OBS_ID in which the source is detected is reported.
Source names that end in X, such as 2CXO J100434.2+411242X represent "extended" sources, for which not all properties are measured.
The script uses the NED name resolver to translate the name into a position. Setting the verbose level to 2 or higher displays the position.
unix% search_csc "SDSS J1004+4112" radius=1 outfile=none verbose=2 cat=latest
...
Resolved SDSS J1004+4112 to ra=151.1455658 dec=41.21185
...
The separation between the detected sources and the input coordinates are provided in the sepn (separation) column in the same units at the radius (default is arcmin).
Additional source properties can be requested by adding them to the columns parameter:
unix% search_csc "SDSS J1004+4112" radius=1 outfile= \ columns=m.significance,m.flux_aper_b,o.theta,o.cnts_aper_b cat=latest ... name ra dec sepn obsid significance flux_aper_b theta cnts_aper_b 2CXO J100430.8+411208 1.511285e+02 4.120248e+01 0.95' 5794 1.58 0.000e+00 1.877 3 2CXO J100430.8+411208 1.511285e+02 4.120248e+01 0.95' 19635 1.58 0.000e+00 1.131 1 ... 2CXO J100434.2+411220 1.511428e+02 4.120560e+01 0.4' 19637 53.52 8.788e-14 0.158 423 2CXO J100434.2+411242X 1.511421e+02 4.121243e+01 0.16' 11546 44.71 NaN 0.290 217 2CXO J100434.2+411242X 1.511421e+02 4.121243e+01 0.16' 11547 44.71 NaN 0.305 252 2CXO J100434.2+411242X 1.511421e+02 4.121243e+01 0.16' 11548 44.71 NaN 0.286 218 ... 2CXO J100438.7+411249 1.511613e+02 4.121383e+01 0.72' 19636 4.94 1.595e-15 1.192 3 2CXO J100438.7+411249 1.511613e+02 4.121383e+01 0.72' 19637 4.94 1.595e-15 0.830 5
Here we ask, for example, for the source significance [m.significance], the broad band (0.5-7.0 keV) flux [m.flux_aper_b], the location of the source relative to the optical axis [o.theta], and the number of broad band counts [o.cnts_aper_b]. The list of columns is quite extensive and includes all the columns discussed in the CSC Column-description pages. The o denotes an "observation" source property, computed from a single OBS_ID and m denotes a "master" source property which is computed from data from all the OBS_IDs a source was detected.
We can change the units of the search radius and it will change the units of the sepn values:
unix% search_csc "SDSS J1004+4112" radius=2 radunit=arcsec out= cat=latest
search_csc
pos = SDSS J1004+4112
radius = 2
outfile =
radunit = arcsec
columns = INDEF
sensitivity = no
download = none
root = ./
bands = broad,wide
filetypes = regevt,pha,arf,rmf,lc,psf,regexp
catalog = latest
verbose = 1
clobber = no
mode = ql
17 rows returned by query
1 Different Master Source(s).
17 Different Observation(s).
name ra dec sepn obsid
2CXO J100434.9+411242 1.511455e+02 4.121186e+01 0.22" 5794
2CXO J100434.9+411242 1.511455e+02 4.121186e+01 0.22" 19635
2CXO J100434.9+411242 1.511455e+02 4.121186e+01 0.22" 11546
2CXO J100434.9+411242 1.511455e+02 4.121186e+01 0.22" 11547
2CXO J100434.9+411242 1.511455e+02 4.121186e+01 0.22" 11548
2CXO J100434.9+411242 1.511455e+02 4.121186e+01 0.22" 11549
2CXO J100434.9+411242 1.511455e+02 4.121186e+01 0.22" 14495
2CXO J100434.9+411242 1.511455e+02 4.121186e+01 0.22" 14496
2CXO J100434.9+411242 1.511455e+02 4.121186e+01 0.22" 14497
2CXO J100434.9+411242 1.511455e+02 4.121186e+01 0.22" 14498
2CXO J100434.9+411242 1.511455e+02 4.121186e+01 0.22" 14499
2CXO J100434.9+411242 1.511455e+02 4.121186e+01 0.22" 14500
2CXO J100434.9+411242 1.511455e+02 4.121186e+01 0.22" 19632
2CXO J100434.9+411242 1.511455e+02 4.121186e+01 0.22" 19633
2CXO J100434.9+411242 1.511455e+02 4.121186e+01 0.22" 19634
2CXO J100434.9+411242 1.511455e+02 4.121186e+01 0.22" 19636
2CXO J100434.9+411242 1.511455e+02 4.121186e+01 0.22" 19637
When the output file is "none" or left blank, the source properties are only printed to the screen (with verbose >0). We can set the output file and it will save the Tab Separated Value (TSV) format results.
unix% search_csc "SDSS J1004+4112" radius=1 outfile=sdss_j1004+4112.tsv \
columns=m.significance,m.flux_aper_b,o.theta,o.cnts_aper_b verbose=0 cat=latest
unix% cat sdss_j1004+4112.tsv
#Column sepn (E9.6) (.sepn) [""] []
#Column name (A22) Source name in the format '2CXO Jhhmmss.s{+|-}ddmmss[X]' (master_source.name) [""] []
#Column ra (E9.6) Source position, ICRS right ascension (master_source.ra) ["deg"] [pos.eq.ra;meta.main]
#Column dec (E9.6) Source position, ICRS declination (master_source.dec) ["deg"] [pos.eq.dec;meta.main]
#Column instrument (A4) Instrument used for the observation; 'ACIS' or 'HRC' (observation_source.instrument) [""] []
#Column obsid (I5) Observation identifier (observation_source.obsid) [""] []
#Column obi (I3) Observation interval number (observation_source.obi) [""] []
#Column region_id (I4) Detection region identifier (component number) (observation_source.region_id) [""] []
#Column match_type (A1) Type of match between master source and stacked observation detection; u = unique match, a = ambiguous match; n = non-detection (master_stack_assoc.match_type) [""] [meta.code]
#Column detect_stack_id (A24) Detect stack identifier (designation of observation stack used for source detection) in the format '{acis|hrc}fJhhmmsss{p|m}ddmmss_nnn' (stack_source.detect_stack_id) [""] []
#Column significance (F9.2) Highest flux significance (S/N) across all stacked observations and energy bands (master_source.significance) [""] []
#Column flux_aper_b (E9.3) Aperture-corrected net energy flux inferred from the source region aperture, best estimate derived from the longest block of a multi-band, flux-ordered Bayesian Block analysis of the contributing observations, and calculated by counting X-ray events; ACIS broad (0.5-7.0 keV) energy band (master_source.flux_aper_b) ["erg/s/cm^2"] []
#Column theta (F9.3) PSF 90% ECF aperture off-axis angle (observation_source.theta) ["arcmin"] []
#Column cnts_aper_b (I11) Total counts observed in the modified source region aperture; ACIS broad (0.5-7.0 keV) energy band (observation_source.cnts_aper_b) ["count"] []
sepn name ra dec instrument obsid obi region_id match_type detect_stack_id significance flux_aper_b theta cnts_aper_b
5.721851e+01 2CXO J100430.8+411208 1.511285e+02 4.120248e+01 ACIS 5794 0 133 n acisfJ1004335p411357_002 1.58 0.000e+00 1.877 3
5.721851e+01 2CXO J100430.8+411208 1.511285e+02 4.120248e+01 ACIS 19635 0 133 n acisfJ1004335p411357_002 1.58 0.000e+00 1.131 1
5.721851e+01 2CXO J100430.8+411208 1.511285e+02 4.120248e+01 ACIS 11546 0 39 u acisfJ1004338p411243_002 1.58 0.000e+00 0.590 1
...
2.374986e+01 2CXO J100434.2+411220 1.511428e+02 4.120560e+01 ACIS 19637 0 41 u acisfJ1004338p411243_002 53.52 8.788e-14 0.158
423
9.632274e+00 2CXO J100434.2+411242X 1.511421e+02 4.121243e+01 ACIS 11546 0 9001 u acisfJ1004338p411243_002 44.71 NaN 0.290
217
9.632274e+00 2CXO J100434.2+411242X 1.511421e+02 4.121243e+01 ACIS 11547 0 9001 u acisfJ1004338p411243_002 44.71 NaN 0.305
252
...
4.329478e+01 2CXO J100438.7+411249 1.511613e+02 4.121383e+01 ACIS 19634 0 53 u acisfJ1004338p411243_002 4.94 1.595e-15 0.654 5
4.329478e+01 2CXO J100438.7+411249 1.511613e+02 4.121383e+01 ACIS 19636 0 53 u acisfJ1004338p411243_002 4.94 1.595e-15 1.192 3
4.329478e+01 2CXO J100438.7+411249 1.511613e+02 4.121383e+01 ACIS 19637 0 53 u acisfJ1004338p411243_002 4.94 1.595e-15 0.830 5
Users will notice that some additional columns are also included: obi, region_id, match_type, and instrument. These columns are required by the script and are always included in the results. Also users should be aware that - contrary to what happens when the results are just printed to the screen - the sepn value is always saved in units of arcsec regardless of the radunit value.
When the default columns=INDEF is set, many of the most common columns are retrieved and saved to the output file; however, only a few are printed to the screen.
Search by OBS_ID
After reviewing the above results, we notice that most of the sources belong to the same Chandra obsid: 5794. Let us now widen our search and see which other sources were also detected in this observation. To do this we switch to use the obsid_search_csc tool:
unix% obsid_search_csc 5794 out= cat=latest \
column=o.theta,o.cnts_aper_b,o.ks_prob_b,o.flux_significance_b
obsid_search_csc
obsid = 5794
outfile =
columns = o.theta,o.cnts_aper_b,o.ks_prob_b,o.flux_significance_b
download = none
root = ./
bands = broad,wide
filetypes = regevt,pha,arf,rmf,lc,psf,regexp
catalog = latest
verbose = 1
clobber = no
mode = ql
69 rows returned by query
69 Different Master Source(s).
1 Different Observation(s).
name ra dec obsid theta cnts_aper_b ks_prob_b flux_significance_b
2CXO J100414.3+411259 1.510596e+02 4.121640e+01 5794 3.737 91 0.767 8.30
2CXO J100415.2+411155 1.510633e+02 4.119877e+01 5794 3.995 150 0.956 10.84
2CXO J100416.0+410938 1.510668e+02 4.116079e+01 5794 5.419 8 NaN 0.00
2CXO J100416.6+410813 1.510697e+02 4.113692e+01 5794 6.555 47 0.962 4.43
2CXO J100416.7+411204 1.510699e+02 4.120120e+01 5794 3.665 21 0.216 3.58
2CXO J100417.4+411428 1.510728e+02 4.124133e+01 5794 3.056 6 NaN 0.00
2CXO J100419.0+411029 1.510790e+02 4.117501e+01 5794 4.406 45 0.184 5.50
2CXO J100419.4+411024 1.510810e+02 4.117345e+01 5794 4.430 67 0.800 6.96
2CXO J100419.4+411355 1.510809e+02 4.123211e+01 5794 2.646 4 NaN 1.32
2CXO J100419.9+411154 1.510829e+02 4.119837e+01 5794 3.281 18 0.532 3.47
2CXO J100420.3+411414 1.510846e+02 4.123734e+01 5794 2.496 99 0.565 8.83
2CXO J100421.3+411054 1.510888e+02 4.118179e+01 5794 3.817 5 NaN 1.16
2CXO J100422.6+411438 1.510944e+02 4.124396e+01 5794 2.147 4 NaN 0.00
2CXO J100423.9+411428 1.510997e+02 4.124110e+01 5794 1.870 11 0.656 2.70
2CXO J100424.1+410828 1.511005e+02 4.114139e+01 5794 5.754 21 NaN 1.82
2CXO J100425.2+411158 1.511053e+02 4.119973e+01 5794 2.507 49 0.381 6.01
2CXO J100427.5+411057 1.511143e+02 4.118238e+01 5794 3.223 10 NaN 2.38
2CXO J100427.5+411232 1.511148e+02 4.120909e+01 5794 1.803 4 NaN 0.00
2CXO J100428.1+411245 1.511172e+02 4.121277e+01 5794 1.560 1 NaN 0.00
2CXO J100428.3+411128 1.511182e+02 4.119132e+01 5794 2.659 19 0.338 3.76
2CXO J100428.5+411229 1.511188e+02 4.120825e+01 5794 1.738 3 NaN 0.00
2CXO J100429.2+411354 1.511216e+02 4.123185e+01 5794 0.810 14 0.327 3.06
2CXO J100430.1+410944 1.511257e+02 4.116229e+01 5794 4.269 69 0.756 6.99
2CXO J100430.3+411414 1.511266e+02 4.123738e+01 5794 0.650 19 0.026 3.59
2CXO J100430.5+411151 1.511274e+02 4.119769e+01 5794 2.167 0 NaN 0.00
2CXO J100430.6+411322 1.511276e+02 4.122297e+01 5794 0.790 7 0.763 2.21
2CXO J100430.6+411405 1.511275e+02 4.123490e+01 5794 0.562 29 0.449 4.70
2CXO J100430.8+411208 1.511285e+02 4.120248e+01 5794 1.877 3 NaN 0.00
2CXO J100431.6+410936 1.511318e+02 4.116010e+01 5794 4.366 448 0.525 18.81
2CXO J100433.4+411019 1.511392e+02 4.117216e+01 5794 3.637 16 0.960 2.73
2CXO J100433.6+411307 1.511403e+02 4.121864e+01 5794 0.841 33 1.000 4.67
2CXO J100433.8+411018 1.511410e+02 4.117181e+01 5794 3.652 94 0.468 8.40
2CXO J100433.8+411234 1.511409e+02 4.120963e+01 5794 1.383 1275 0.350 30.92
2CXO J100434.0+411248 1.511419e+02 4.121357e+01 5794 1.150 705 0.502 22.84
2CXO J100434.1+410840 1.511423e+02 4.114450e+01 5794 5.310 20 0.236 2.83
2CXO J100434.1+411243 1.511424e+02 4.121217e+01 5794 1.236 72 0.976 4.86
2CXO J100434.2+411220 1.511428e+02 4.120560e+01 5794 1.629 886 0.190 25.87
2CXO J100434.2+411439 1.511429e+02 4.124442e+01 5794 0.722 1 NaN 0.00
2CXO J100434.8+411239 1.511450e+02 4.121087e+01 5794 1.329 1204 0.073 30.15
2CXO J100434.9+411242 1.511455e+02 4.121186e+01 5794 1.276 1520 0.700 34.78
2CXO J100435.6+410806 1.511484e+02 4.113506e+01 5794 5.868 14 NaN 0.00
2CXO J100436.3+410946 1.511514e+02 4.116298e+01 5794 4.212 35 0.486 4.72
2CXO J100437.0+411109 1.511543e+02 4.118595e+01 5794 2.881 16 0.048 3.14
2CXO J100437.0+411532 1.511543e+02 4.125894e+01 5794 1.711 19 0.304 3.47
2CXO J100437.1+411231 1.511548e+02 4.120886e+01 5794 1.586 166 0.831 11.41
2CXO J100437.2+410838 1.511554e+02 4.114408e+01 5794 5.361 14 NaN 0.00
2CXO J100437.2+411445 1.511552e+02 4.124584e+01 5794 1.060 165 0.578 11.44
2CXO J100438.1+411004 1.511589e+02 4.116798e+01 5794 3.974 9 NaN 1.20
2CXO J100438.3+411124 1.511597e+02 4.119010e+01 5794 2.713 4 NaN 1.09
2CXO J100438.7+411249 1.511613e+02 4.121383e+01 5794 1.495 11 0.769 2.42
2CXO J100438.8+411507 1.511617e+02 4.125188e+01 5794 1.527 6 0.822 2.05
2CXO J100439.5+411446 1.511648e+02 4.124626e+01 5794 1.403 9 0.534 2.43
2CXO J100441.0+410943 1.511708e+02 4.116221e+01 5794 4.456 498 0.350 19.84
2CXO J100441.0+411538 1.511710e+02 4.126080e+01 5794 2.205 4 NaN 0.00
2CXO J100441.3+411110 1.511722e+02 4.118619e+01 5794 3.156 20 0.467 3.76
2CXO J100441.6+410819 1.511736e+02 4.113873e+01 5794 5.841 23 NaN 2.80
2CXO J100441.9+411226 1.511746e+02 4.120736e+01 5794 2.195 6 NaN 1.85
2CXO J100442.0+411059 1.511752e+02 4.118322e+01 5794 3.374 79 0.623 7.60
2CXO J100442.8+411400 1.511784e+02 4.123355e+01 5794 1.755 0 NaN 0.00
2CXO J100443.0+411342 1.511795e+02 4.122844e+01 5794 1.822 9 0.842 2.61
2CXO J100444.9+411348 1.511872e+02 4.123014e+01 5794 2.158 99 0.778 8.90
2CXO J100445.8+411246 1.511909e+02 4.121292e+01 5794 2.601 9 0.507 2.38
2CXO J100445.8+411308 1.511910e+02 4.121894e+01 5794 2.461 5 NaN 0.00
2CXO J100446.0+411215 1.511917e+02 4.120434e+01 5794 2.907 28 0.597 4.49
2CXO J100446.4+411447 1.511933e+02 4.124666e+01 5794 2.570 115 0.706 9.47
2CXO J100451.7+410831 1.512156e+02 4.114196e+01 5794 6.428 127 0.942 7.40
2CXO J100451.9+410911 1.512169e+02 4.115328e+01 5794 5.899 41 0.058 2.50
2CXO J100453.4+411306 1.512226e+02 4.121860e+01 5794 3.841 9 NaN 0.00
2CXO J100454.7+411231 1.512281e+02 4.120867e+01 5794 4.249 6 NaN 0.00
We see that there were a total of 69 sources covered by this observation. In CSC version 2 and later: sources are detected on combined datasets; but source properties are computed for all sources in each individual obsid. The columns parameter accepts the same inputs as the search_csc script and the screen and file outputs behave the same. The only difference is that there is no sepn column returned: since we are searching by observation there is no distance to compute.
Other Observations?
One might wonder if the original position was observed multiple times? We can try the find_chandra_obsid tool:
unix% find_chandra_obsid "SDSS J1004+4112" # obsid sepn inst grat time obsdate piname target 5794 0.2 ACIS-S NONE 80.1 2005-01-01 Inada "SDSS J1004+4112" 14499 0.1 ACIS-S NONE 23.3 2014-04-29 Kochanek SDSS1004+4112 11548 0.1 ACIS-S NONE 6.0 2010-09-23 Kochanek SDSS1004+4112 11549 0.1 ACIS-S NONE 6.0 2011-01-30 Kochanek SDSS1004+4112 14495 0.1 ACIS-S NONE 24.7 2013-01-27 Kochanek SDSS1004+4112 14500 0.1 ACIS-S NONE 24.7 2014-06-02 Kochanek SDSS1004+4112 19633 0.1 ACIS-S NONE 39.5 2017-04-16 Chartas SDSS1004+4112 19636 0.1 ACIS-S NONE 36.0 2018-01-17 Chartas SDSS1004+4112 14497 0.1 ACIS-S NONE 24.1 2013-10-05 Kochanek SDSS1004+4112 14498 0.1 ACIS-S NONE 23.8 2013-11-16 Kochanek SDSS1004+4112 11546 0.1 ACIS-S NONE 6.0 2010-03-08 Kochanek SDSS1004+4112 11547 0.1 ACIS-S NONE 6.0 2010-06-19 Kochanek SDSS1004+4112 14496 0.1 ACIS-S NONE 24.7 2013-03-01 Kochanek SDSS1004+4112 19634 0.1 ACIS-S NONE 35.9 2017-06-27 Chartas SDSS1004+4112 19632 0.1 ACIS-S NONE 40.1 2017-01-23 Chartas SDSS1004+4112 19635 0.1 ACIS-S NONE 38.4 2017-10-01 Chartas SDSS1004+4112 19637 0.1 ACIS-S NONE 39.5 2018-04-19 Chartas SDSS1004+4112
We can see that there are 16 other observations that imaged our source. However, not all observations are guaranteed to be in a particular release of the Chandra Source Catalog, as the observation may only have become public after the deadline for the catalog release.
Retrieve Data Products
The data products used to create the source properties are also available for each source. This includes both observation level products, like full field event files, exposure maps, and background images, as well as per source products such as PSFs, ARF, RMF, spectra, and light-curves.
Both search_csc and obsid_search_csc have a download parameter. If set to none (default) no data products are retrieved. If set to ask or all then data products for each source and each observation will be downloaded as specified in the bands and filetypes parameters. To retrieve all the default data products for a small search would look something like this:
unix% search_csc "SDSS J1004+4112" radius=1 radunit=arcsec outfile= download=ask verbose=0 cat=latest Download data for 2CXO J100434.9+411242 in 05794_000 [y,n,a,q]: y Download data for 2CXO J100434.9+411242 in 19635_000 [y,n,a,q]: y Download data for 2CXO J100434.9+411242 in 11546_000 [y,n,a,q]: q Skipping remaining sources
which creates a number of files stored by the source and observation identifier (these files are gzip compressed):
unix% tree 2CXOJ100434.9+411242 2CXOJ100434.9+411242 ├── 05794_000 │ ├── acisf05794_000N027_r0026_arf3.fits.gz │ ├── acisf05794_000N027_r0026b_lc3.fits.gz │ ├── acisf05794_000N027_r0026b_psf3.fits.gz │ ├── acisf05794_000N027_r0026b_regexp3.fits.gz │ ├── acisf05794_000N027_r0026_pha3.fits.gz │ ├── acisf05794_000N027_r0026_regevt3.fits.gz │ └── acisf05794_000N027_r0026_rmf3.fits.gz └── 19635_000 ├── acisf19635_000N027_r0026_arf3.fits.gz ├── acisf19635_000N027_r0026b_lc3.fits.gz ├── acisf19635_000N027_r0026b_psf3.fits.gz ├── acisf19635_000N027_r0026b_regexp3.fits.gz ├── acisf19635_000N027_r0026_pha3.fits.gz ├── acisf19635_000N027_r0026_regevt3.fits.gz └── acisf19635_000N027_r0026_rmf3.fits.gz 3 directories, 14 files
If we use the obsid_search_csc script the same data products can be retrieved, but they are stored in a slightly different directory structure
unix% obsid_search_csc 5794 download=ask outfile="" col=INDEF filetypes=evt,pha,arf,rmf verb=0 cat=latest Download data for 2CXO J100414.3+411259 in 05794_000 [y,n,a,q]: y Download data for 2CXO J100415.2+411155 in 05794_000 [y,n,a,q]: y Download data for 2CXO J100416.0+410938 in 05794_000 [y,n,a,q]: q Skipping remaining sources
Now the directory structure starts with the OBS_ID and with a sub directory for each source. Since the evt file is common to all the sources, it is stored in the OBS_ID directory. Note: by entering 'q' when prompted we quit out of downloading any more data products, so only the files for the first two sources were retrieved.
unix% tree 5794 5794 ├── acisf05794_000N027_evt3.fits.gz ├── r0018 │ ├── acisf05794_000N027_r0018_arf3.fits.gz │ ├── acisf05794_000N027_r0018_pha3.fits.gz │ └── acisf05794_000N027_r0018_rmf3.fits.gz └── r0097 ├── acisf05794_000N020_r0097_arf3.fits.gz ├── acisf05794_000N020_r0097_pha3.fits.gz └── acisf05794_000N020_r0097_rmf3.fits.gz 3 directories, 7 files
Using results with CIAO
The TSV format file that is returned by the CSC CLI interface and these scripts can be used by both CIAO and ds9.
unix% unix% obsid_search_csc 5794 out=5794.tsv cat=latest \ column=o.theta,o.cnts_aper_b,o.ks_prob_b,o.flux_significance_b verb=0 clob+
DM ASCII Kernel
To use the output with CIAO tools you must explicitly specify that the file is in TSV format using the [opt kernel=text/tsv] directive as part of the virtual file syntax.
unix% dmlist 5794.tsv"[opt kernel=text/tsv]" blocks
--------------------------------------------------------------------------------
Dataset: 5794.tsv
--------------------------------------------------------------------------------
Block Name Type Dimensions
--------------------------------------------------------------------------------
Block 1: 5794.tsv Table 13 cols x 69 rows
unix% dmlist 5794.tsv"[opt kernel=text/tsv]" cols
--------------------------------------------------------------------------------
Columns for Table Block 5794.tsv
--------------------------------------------------------------------------------
ColNo Name Unit Type Range
1 name String[22] Source name in the format '2CXO Jhhmmss.s{+|-}ddmmss[X]'
2 ra deg Real4 -Inf:+Inf Source position, ICRS right ascension
3 dec deg Real4 -Inf:+Inf Source position, ICRS declination
4 instrument String[4] Instrument used for the observation; 'ACIS' or 'HRC'
5 obsid Int4 - Observation identifier
6 obi Int4 - Observation interval number
7 region_id Int4 - Detection region identifier (component number)
8 match_type String[1] Type of match between master source and stacked observation detection; u = uniqu
9 detect_stack_id String[24] Detect stack identifier (designation of observation stack used for source detect
10 theta arcmin Real4 -Inf:+Inf PSF 90% ECF aperture off-axis angle
11 cnts_aper_b count Int4 - Total counts observed in the modified source region aperture; ACIS broad (0.5-7.
12 ks_prob_b Real4 -Inf:+Inf Intra-observation Kolmogorov-Smirnov test variability probability; ACIS broad (0
13 flux_significance_b Real4 -Inf:+Inf Significance of the single-observation detection determined from the ratio of th
unix% dmlist "5794.tsv[opt kernel=text/tsv][cols name,theta,flux_significance_b]" data,clean # name theta flux_significance_b 2CXO J100414.3+411259 3.7369999886 8.3000001907 2CXO J100415.2+411155 3.9949998856 10.8400001526 2CXO J100416.0+410938 5.4190001488 0 2CXO J100416.6+410813 6.5549998283 4.4299998283 2CXO J100416.7+411204 3.6649999619 3.5799999237 2CXO J100417.4+411428 3.0559999943 0 2CXO J100419.0+411029 4.4060001373 5.50 2CXO J100419.4+411024 4.4299998283 6.9600000381 2CXO J100419.4+411355 2.6459999084 1.3200000525 2CXO J100419.9+411154 3.2809998989 3.4700000286 2CXO J100420.3+411414 2.4960000515 8.8299999237 2CXO J100421.3+411054 3.8169999123 1.1599999666 2CXO J100422.6+411438 2.1470000744 0 2CXO J100423.9+411428 1.8700000048 2.7000000477 2CXO J100424.1+410828 5.7540001869 1.8200000525 2CXO J100425.2+411158 2.5069999695 6.0100002289 2CXO J100427.5+411057 3.2230000496 2.3800001144 2CXO J100427.5+411232 1.8029999733 0 2CXO J100428.1+411245 1.5599999428 0 2CXO J100428.3+411128 2.6589999199 3.7599999905 2CXO J100428.5+411229 1.7380000353 0 2CXO J100429.2+411354 0.81000000238419 3.0599999428 2CXO J100430.1+410944 4.2690000534 6.9899997711 2CXO J100430.3+411414 0.64999997615814 3.5899999142 2CXO J100430.5+411151 2.1670000553 0 2CXO J100430.6+411322 0.79000002145767 2.2100000381 2CXO J100430.6+411405 0.56199997663498 4.6999998093 2CXO J100430.8+411208 1.8769999743 0 2CXO J100431.6+410936 4.3660001755 18.8099994659 2CXO J100433.4+411019 3.6370000839 2.7300000191 2CXO J100433.6+411307 0.8410000205040 4.6700000763 2CXO J100433.8+411018 3.6519999504 8.3999996185 2CXO J100433.8+411234 1.3830000162 30.9200000763 2CXO J100434.0+411248 1.1499999762 22.8400001526 2CXO J100434.1+410840 5.3099999428 2.8299999237 2CXO J100434.1+411243 1.2359999418 4.8600001335 2CXO J100434.2+411220 1.6289999485 25.8700008392 2CXO J100434.2+411439 0.72200000286102 0 2CXO J100434.8+411239 1.3289999962 30.1499996185 2CXO J100434.9+411242 1.2760000229 34.7799987793 2CXO J100435.6+410806 5.8680000305 0 2CXO J100436.3+410946 4.2119998932 4.7199997902 2CXO J100437.0+411109 2.8810000420 3.1400001049 2CXO J100437.0+411532 1.7109999657 3.4700000286 2CXO J100437.1+411231 1.5859999657 11.4099998474 2CXO J100437.2+410838 5.3610000610 0 2CXO J100437.2+411445 1.0599999428 11.4399995804 2CXO J100438.1+411004 3.9739999771 1.2000000477 2CXO J100438.3+411124 2.7130000591 1.0900000334 2CXO J100438.7+411249 1.4950000048 2.4200000763 2CXO J100438.8+411507 1.5269999504 2.0499999523 2CXO J100439.5+411446 1.4029999971 2.4300000668 2CXO J100441.0+410943 4.4559998512 19.8400001526 2CXO J100441.0+411538 2.2049999237 0 2CXO J100441.3+411110 3.1559998989 3.7599999905 2CXO J100441.6+410819 5.8410000801 2.7999999523 2CXO J100441.9+411226 2.1949999332 1.8500000238 2CXO J100442.0+411059 3.3740000725 7.5999999046 2CXO J100442.8+411400 1.7549999952 0 2CXO J100443.0+411342 1.8220000267 2.6099998951 2CXO J100444.9+411348 2.1579999924 8.8999996185 2CXO J100445.8+411246 2.6010000706 2.3800001144 2CXO J100445.8+411308 2.4609999657 0 2CXO J100446.0+411215 2.9070000648 4.4899997711 2CXO J100446.4+411447 2.5699999332 9.4700002670 2CXO J100451.7+410831 6.4279999733 7.4000000954 2CXO J100451.9+410911 5.8990001678 2.50 2CXO J100453.4+411306 3.8410000801 0 2CXO J100454.7+411231 4.2490000725 0
unix% dmstat "5794.tsv[opt kernel=text/tsv][cols ks_prob_b]" sig+ med+
ks_prob_b
min: 0.026000000536 @: 24
max: 1 @: 31
mean: 0.55333333181
median: 0.5339999795
sigma: 0.27523266807
sum: 24.899999931
good: 45
null: 24
unix% dmsort "5794.tsv[opt kernel=text/tsv]" sort_by_theta.fits theta cl+
See also ahelp dmascii
Using with SAOImage ds9
The TSV file can be loaded directly into SAOImage ds9. You can load it via the command line
unix% unix% ds9 5794/acisf05794_000N001_evt3.fits.gz -catalog import tsv 5794.tsv
Or the file can be loaded from with the GUI itself. Once the event file is loaded you can goto: Analysis → Catalog Tool ... then in the catalog tool window goto File → Import → Tab-Separated-Value → 5794.tsv
![[The DS9 window displaying a portion of the event file for this observation, along with circles marking the sources found in the Chandra Source Catalog.]](ds9_data.png)
The main window diplays the binned event file along with the sources listed in the TSV file.
![[The DS9 catalog window displaying a portion of the rows and columns read in from the TSV file.]](ds9_tsv.png)
The catalog window diplays the sources loaded from the TSV file.
Users can then use the catalog tool to interact with the catalog table and source properties. The data can also be transmitted to other SAMP enabled applications such as TOPCAT.
The table-display support in DS9 (the prism option) can be used to display the contents of the TSV file. For example, from the command line:
unix% ds9 -prism import tsv 5794.tsv
![[The DS9 prism window displaying a portion of the rows and columns read in from the TSV file.]](prism_tsv.png)
The prism window diplays the sources loaded from the TSV file.
Upper Limits
There is no simple command-line access to the upper-limit values for a location in CSC 2.2. The available options are:
- Use of the Chandra Source Catalog 2.2 Quick Search web page, which can provide per-source information, but is not useful if there are many sources.
- The CSCView application.
- Download the sensity file types for the source with search_csc and then identify the values with tools like evalpos, dmstat, or dmimgpick, or by accessing the data via Python.
As an example of using search_csc, here picking up the broad-band, hard-band, and wide-band (for HRC) sensitivity images:
unix% search_csc '38.94521969459174, 34.68734478897538' 0.1 outfile= bands=broad,hard,wide filetypes=sensity catalog=latest download=all
search_csc
pos = 38.94521969459174, 34.68734478897538
radius = 0.1
outfile =
radunit = arcmin
columns = INDEF
sensitivity = no
download = all
root = ./
bands = broad,hard,wide
filetypes = sensity
catalog = latest
verbose = 1
clobber = no
mode = ql
2 rows returned by query
1 Different Master Source(s).
2 Different Observation(s).
name ra dec sepn obsid
2CXO J023546.8+344115 3.894522e+01 3.468734e+01 5.1e-05' 26201
2CXO J023546.8+344115 3.894522e+01 3.468734e+01 5.1e-05' 1870
Retrieving files for obsid_obi 26201_000
Retrieved file ./2CXOJ023546.8+344115/acisfJ0235459p344051_001/acisfJ0235459p344051_001N020_b_sens3.fits
Retrieved file ./2CXOJ023546.8+344115/acisfJ0235459p344051_001/acisfJ0235459p344051_001N020_h_sens3.fits
Retrieving files for obsid_obi 01870_000
Retrieved file ./2CXOJ023546.8+344115/hrcfJ0235467p344100_001/hrcfJ0235467p344100_001N028_w_sens3.fits
unix% tree 2CXOJ023546.8+344115 2CXOJ023546.8+344115 ├── acisfJ0235459p344051_001 │ ├── acisfJ0235459p344051_001N020_b_sens3.fits.gz │ └── acisfJ0235459p344051_001N020_h_sens3.fits.gz └── hrcfJ0235467p344100_001 └── hrcfJ0235467p344100_001N028_w_sens3.fits.gz 3 directories, 3 files
The structure and meaning of the "sens3" files is dicussed at the Stacked Observation Detections Limiting Sensitivity Map page:
unix% dmlist acisfJ0235459p344051_001N020_h_sens3.fits.gz blocks
--------------------------------------------------------------------------------
Dataset: acisfJ0235459p344051_001N020_h_sens3.fits.gz
--------------------------------------------------------------------------------
Block Name Type Dimensions
--------------------------------------------------------------------------------
Block 1: SENSITY0 Image Real8(169x169)
Block 2: SENSITY1 Image Real8(169x169)
unix% dmlist 2CXOJ023546.8+344115/acisfJ0235459p344051_001/acisfJ0235459p344051_001N020_h_sens3.fits.gz cols
--------------------------------------------------------------------------------
Columns for Image Block SENSITY0
--------------------------------------------------------------------------------
ColNo Name Unit Type Range
1 SENSITY0[169,169] photon cm^-2 s^-1 Real8(169x169) -Inf:+Inf
--------------------------------------------------------------------------------
Physical Axis Transforms for Image Block SENSITY0
--------------------------------------------------------------------------------
Group# Axis#
1 1,2 sky(x) = (+3114.50) +(+8.0)* ((#1)-(+0.50))
(y) (+3562.50) (+8.0) ((#2) (+0.50))
--------------------------------------------------------------------------------
World Coordinate Axis Transforms for Image Block SENSITY0
--------------------------------------------------------------------------------
Group# Axis#
1 1,2 EQPOS(RA ) = (+38.9416)[deg] +TAN[(-0.000136667)* (sky(x)-(+4096.50))]
(DEC) (+34.6808) (+0.000136667) ( (y) (+4096.50))
Tools and scripts can be used to query these files: for example using the stack support in evalpos we can query the two blocks SENSITY0 - which represents the MARGINAL source likelihood threshold - and SENSITY1 - which represents the TRUE source likelihood threshold:
unix% evalpos "2CXOJ023546.8+344115/*/*sens3*[sensity0]" 38.94521969459174 34.68734478897538 acisfJ0235459p344051_001N020_b_sens3.fits.gz[sensity0] 38.94521969459174 34.68734478897538 1.70836e-06 [photon cm^-2 s^-1] acisfJ0235459p344051_001N020_h_sens3.fits.gz[sensity0] 38.94521969459174 34.68734478897538 7.3834e-07 [photon cm^-2 s^-1] hrcfJ0235467p344100_001N027_w_sens3.fits.gz[sensity0] 38.94521969459174 34.68734478897538 5.76335e-06 [photon cm^-2 s^-1]
unix% evalpos "2CXOJ023546.8+344115/*/*sens3*[sensity1]" 38.94521969459174 34.68734478897538 acisfJ0235459p344051_001N020_b_sens3.fits.gz[sensity1] 38.94521969459174 34.68734478897538 2.59335e-06 [photon cm^-2 s^-1] acisfJ0235459p344051_001N020_h_sens3.fits.gz[sensity1] 38.94521969459174 34.68734478897538 1.15573e-06 [photon cm^-2 s^-1] hrcfJ0235467p344100_001N027_w_sens3.fits.gz[sensity1] 38.94521969459174 34.68734478897538 7.2541e-06 [photon cm^-2 s^-1]
More options?
Users who need to construct more complicated queries (eg variable sources with some range of hardness ratios etc.) or who need to perform cross matches, must use the CSCView application or use the CSCCLI interface directly. The How to access the Chandra Source Catalog Release 2.2 page provides more information.
Research that makes use of the data in the catalog should see the How to cite the Chandra Source Catalog page.
History
| 25 Jul 2013 | Initial version. |
| 25 Nov 2013 | Review for CIAO 4.6. No changes. |
| 16 Dec 2014 | Review for CIAO 4.7. No changes. |
| 24 Oct 2019 | Added banner with CSC2 incompatibility. |
| 29 Oct 2019 | Updated with CSC2 example. |
| 09 Dec 2021 | Review for CIAO 4.14. Removed prism for CIAO 4.14. |
| 08 Oct 2026 | Updated for the CSC 2.2 release (use cat=latest). Added an example of using the prism support in DS9 to display the TSV file, and updating the Limiting Sensitivity section. |