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Extragalactic 2

Baldi (Linux), Bonchi (Windows), Cassara' (Windows), Chon (Mac OS X), Finet (Windows/Linux), Fritz (Mac OS X), Guelbenzu (Linux), Leitet (Mac OS X), Messias (Mac OS X), Tepper-Garcia (Mac OS X), Vulcani (Mac OS X)

Schedule Tues March 31.

0900 - 1015

Intrduction: Use cases and participants' (group) projects

Extragalactic 2: use case 3: Searching for Data available for the bright galaxy M51. (Aladin, SIMBAD, VizieR , Topcat, VOSpec)

1045 - 1230


1400 - 1530

Extragalactic 1: use case 1: Confirming a supernova candidate (Aladin, Topcat)

option: Extragalactic 1: use case 2: Search for ULX sources and X-ray binaries in nearby (e.g. D<10 Mpc) galaxies (uses TOPCAT, Aladin).

1600 - 1730

CDS Training Materials







AstroGrid Python Scripting Information and worked examples


Use Case 1

_Based on Eduardo Gonzalez Solare case from the VO Info Day in Lisbon

Use Case 2

Finet Francois

  • search for existing quasars (ra. and decl., z, mag., etc.) in the narrow (+- 30')strip of sky visible at zenith from the Devasthal observatory (lat. +29░22') in order to calibrate astrometrically all objects that will be detected with the International Liquid Mirror Telescope.
  • search for photometric standards in the r', g', i' systems in that same narrow strip of sky
  • identification of high proper motion objects and stars with known trigonometric parallaxes in that band of sky
  • production of long images at different wavelengths of that strip of sky based upon existing space and ground based observations

Use Case3: Searching for Data available for the bright galaxy M51. (Aladin, SIMBAD, VizieR , Topcat, VOSpec)

Mark Allen

  • Search for images of the bright galaxy M51 in Aladin.
  • Try the various image servers: The Aladin image server, Skyview and Sloan Digitial Sky Survey
  • Try the 'all VO' access (selecting image servers) - Note the method for selecting images at a given sky location. Clicking in the image puts a tick in the selection boxes of the available data.
  • Make a colour composite image using the RGB tool.
  • Use the multi-view windows to manage the various images you have in the 'stack'
  • Try the 'match' button at the bottom of the image window to align the image for synchronized zooming
  • Try the transparency control for viewing images overlaid on each other
  • Overlay as SIMBAD identifications using the SIMBAD link in the Server selector window

- Try 'with no filter' for a simple listsing of the IDs
- Try with 'Simbad filter' (colorized) to see how the same info can be presented in detail
(optional - open the 'properties' window for the Simbad plane to see or edit the filter)

  • Filtering of sources can also be done interactively with Topcat. Start Topcat, and send the SIMBAD plane to Topcat (right-click on the plane in the stack, and 'Broadcast selected tables to..'
  • View the table values in Topcat. Make a plot of the positions and try the area selection tools to select a number of points in the plot. Note how the selected subset may be transmitted back to Aladin to highlight sources from the original Simbad plane.
  • Make a subset of the brightest HII regions, and send the table back to Aladin using the Topcat 'Interop' menu
  • Search for spectra available in the VO with the 'all VO' button in the server selector window.
  • Find spectra available from the Hubble Space Telescope, and view the positions of the spectra (and sometimes thespectral slit aperture) on the image. Make a plane containing all the spectra positions, and cross match these with the positions of the HII regions.
  • Start VOSpec ( Web Start: ) and display some of the spectra, by clicking on the spectra in the server selector window, and 'Load in -> VOSpec'.
  • Check VizieR for more detailed catalogues of HII emitting regions in M51. This can be done via Aladinor via the more detailed VizieR interface.
  • (Advanced - compile a list of bright HII regions in M51 and query VizieR with this list

Use Case4

Elisabet Leitet

Download IUE and FUSE catalouges (Aladin)

Extract specific object type (TOPCAT)

Cross-correlate the catalogues (TOPCAT)

Measure the EWs of emission lines (VOSpec)

Name LastName

Problems encountered

Please list here any problems, big or small that you found with the VO tools used.

- Aladin: querying for images with the All-VO capability of aladin, the DSS images selected from the aladin image server entries in the returned list do not load, and report an error about RA and DEC rows.

- aladin filters - it is not obvious that one needs to 'apply' a filter before exporting the results to a plane

- topcat - how can one give a table a name so that it shows up with that name in the aladin stack when broadcast there?

- The Aladin (and also the VizieR ) produced fewer targets than downloading directly from the MAST

- Aladin display of row numbers in catalouges (as shown in the layers) not correct

- It would be useful to be able to fit line profiles when measuring EWs in the VO spec (deblending lines). Also, it would be useful to be able to mask regions (or interpolate between chosen points), for example we had a narrow absorption line inside an emission line. Also, it would be nice to control the continuum fit interactively.

-- PaoloPadovani - 02 Mar 2009

  • ExtraGal2.1.pdf: Presentation of project done by participants Ranieri Baldi, Letizia CassarÓ, Franšois Finet, Hugo Messias, Benedetta Vulcani
Topic attachments
I Attachment History Action Size Date Who Comment
Pdfpdf ExtraGal2.1.pdf r1 manage 537.6 K 06 Apr 2009 - 08:47 MarkAllen Presentation of project done by participants Ranieri Baldi, Letizia CassarÓ, Franšois Finet, Hugo Messias, Benedetta Vulcani
Pdfpdf Leitet_Bonchi_final.pdf r1 manage 4857.3 K 06 Apr 2009 - 08:44 MarkAllen Presentation of project done by participants Leitet and Bonchi
Xmlxml vo_3c295.xml r1 manage 1.4 K 31 Mar 2009 - 07:49 AidaSchool  
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Topic revision: r17 - 06 Apr 2009 - MarkAllen
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