Seleste: A Tool For Querying Remote tables

Science Story

The main science story for this tutorial is Connecting Young Star Magnetospheres & Circumstellar Disks but one should also consider reading Quasars, Fermi, ALMA, oh my!: the underlying story is how do we discover and merge panchromatic data from different wavelength regimes to give us insight into underlying physical processes.

Questions

  • Can we deduce a relationship between the disk flux and X-ray flux that might reveal or constrain their coupling?

Tools and Files

../../_images/seleste_logo128.png ../../_images/topcatc3.gif
This tutorial uses the
  • Seleste Java based desktop application
  • TOPCAT Java based desktop application

Combining X-ray and near-IR data on Orion

../../_images/orion.jpg

The goal of this part of the tutorial is to search the Chandra Source Catalog for sources near the Orion Nebula and retrieve their flux and positions. With this data you will then cross-correlate the sources to the 2MASS catalog with a 1 arcsec radius from each and retrieve their magnitudes. Using the merged catalog of X-ray and near-IR measurements we will look for a simple correlation in flux/magnitude.

  1. The application starts in the Guide mode. Click on the Form icon to start building a query.

  2. Click on Services and select Chandra Source Catalog (CSC) TAP Service. This opens the remote tables in the application.

  3. Now you want to select the columns you wish to retain from this service. Open the master_source table in the Contents area on the left.

    1. Select ra, dec, flux_aper90_b and add (+) in the Output Columns area.
  4. We will now build the query to find sources near the center of the Orion nebula and that are close to on-axis for Chandra.

    1. Select the err_ellipse_r0 column and add in the Column Criteria.
    2. Set the filter to < 3 to select on-axis sources; note that the units for the column are given in the metadata panel at the bottom of Seleste.
    3. Add a spatial range search: * (ra < 83.82) AND ra > 83.78) AND (dec < -5.3) AND dec > -5.5)
    4. Hit Submit
  5. In the Jobs window, once the job status shows as Pending hit Run.

  6. When the status becomes Completed view the results and hit Save to save them in a file e.g. csc_orion.xml

    Note

    If your query fails to run you can continue this tutorial by downloading the csc_orion.xml file from here.

  7. Return to the Query form and under Services select GAVO Data Center TAP Service

  8. Hit Upload and upload the table of previously saved Chandra sources (e.g. csc_orion.xml) it will appear as TAP_UPLOAD.user_table in Contents.

    1. Select user_table and add all columns into Output Columns.
  9. From the GAVO tables select the twomass.data table and add the raj2000, dej2000, Jmag, Hmag and Kmag columns to the Output Columns.

  10. Add a Position Search.

    1. Select TAP_UPLOAD.user_table from drop down menu
    2. Select Center around: Other table and Select Table twomass.data
    3. Set Radius 1.0 arcsec
    4. Submit
  11. In the Jobs window hit run

  12. When completed send results to TOPCAT

    1. Calculate hmag-kmag in TOPCAT
    2. Scatter plot log(flux_aper90_b) vs hmag-kmag color.

Independent Exercise

Question

What is the incidence of X-ray activity in different types of galaxies?

Approach

Find optical and X-ray emitting galaxies with redshift > .1 and study their X-ray and optical properties

Resources & Outline

Use the Chandra Source Catalog (CSC) TAP Service and the SDSS DR7 - SLoan Digital Sky Survey Data Release 7 services to extract the relevant X-ray and Optical Properties.

Analysis

Export the merged catalog to TOPCAT for visualization and analysis.

You can download the script seleste_independent_exercise.txt for doing this exercise off this website.

Project Versions

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