Website introduction tutorial

Make simple queries, load query results in TOPCAT, do basic spectral fitting
  1. Go to the main page and type "M51" in the search field, click Search button.

  2. Click on the first source found, 3XMM J132952.5+471144 — you are now on the source page.

  3. On the source page, click and hold to pan the X-ray sky map (initially centered on the source), zoom / unzoom it with your mouse wheel. Click on the layers icon in the image window, choose Base image layer → DSS colored image. Verify that you are looking at the Whirlpool galaxy. Switch the layer back to the XMM PN colored.

  4. Go back to the main page, try another example query to check Andromeda galaxy in X-rays: cone('M31', '1deg') AND sc_det_ml > 800, hit Search.

  5. Click on the settings icon in the top right corner of the browser window. Hover mouse over column names to see short built-in help message. (Wherever you see a column name, hover mouse over it to read this help message). Add ang_distance column from the list of computed attributes to displayed columns by checking it, remove another column you don't need by unchecking it. Don't forget to Save your personal settings. Note that displayed columns now correspond to your settings.

  6. Go to the main page, click Show query docs link below the search field, copy-paste query on ULXes detected more than twice, hit Search.

  7. Click the Diagrams menu item, note that query you entered earlier is saved in the session – that means you plot same set of sources now. Choose sc_hr1 column for X axis, and sc_ep_8_flux for Y axis, mark log checkbox for Y axis as this parameter spans many orders of magnitude. Now click and hold to pan the diagram, zoom with your mouse wheel. Hover mouse pointer over the data point to see source's IAU name. Clicking on a datapoint opens source webpage in new tab. Try to select red source (left hand side of the plot, as we have X-ray color on X axis) and then blue source (right hand side of the plot) and compare it with their colors on X-ray image you see on sources webpages.

  8. Go to the main page, run query is_agn = True and n_detections > 10 and sc_ep_8_flux > 5e-13, remove ang_distance from set of displayed columns as it has no sense when query does not contain coordinates.

  9. Launch TOPCAT application: either from your computer if you have it, or by going to Settings and clicking "Launch TOPCAT" link in the top of pop-up window (you need to give your browser permissions to launch Java web start files; this perfectly safe operation at this website). Then on the query results page, copy "Download detections as FITS" link. Paste it to TOPCAT using File → Open table → Location input field, click Ok. Your query result will be loaded by TOPCAT in a few seconds. Click "Activation Action" button in the main TOPCAT window. Click "View URL as Image" radio button, set url_plot_spectrum_PN as Image Location column, PNG as Image Format, and click Ok in the bottom of the window. Then view this table by double clicking on it in the main TOPCAT window. Now when you click on rows with non-empty url_plot_spectrum_PN column, TOPCAT will show a window with X-ray spectrum plot and you can study spectral evolution of some of the AGN. Change activation action to show another PNG image from the table, e.g. url_plot_tseries_PN column to see AGN timeseries.

  10. Go back to the query results in a browser and click on any of the sources. Scroll page down and see the list of source's detections (individual observations). Click on one of them that have spectrum column set to true. Check its spectrum and timeseries plot (if available). Click "Fit spectrum" link below the spectral plot. Choose instrument and spectral model to fit. Play with parameters, freeze and thaw them, change their min / max and initial values. Click "Fit": in few seconds plot of fitted model with residuals should appear. Text output contains information on fit quality as well as the model flux within selected spectral range.

  11. Launch Aladin from your computer or from the website (using link in the settings pop-up window).

  12. Run query is_ulx = true and has_spectrum = true. In the settings pop-up window click "SAMP status: connect" button and accept incoming connection request in either TOPCAT or Aladin. Your query result table will be loaded automatically in all applications. In Aladin choose File → Progressive sky (HiPS) → Image... → X... → XMM... → XMM PN colored or any other survey of your interest. In TOPCAT check Broadcast Row box in the main window when the newly loaded table is selected in the list of tables. Now make any type of plot in TOPCAT (e.g. menu Graphics → Sky plot) and start clicking on data points. You will see that Aladin shows you their X-ray images, whereas browser also scrolls the webpage to highlight rows selected in TOPCAT.