VOSA. Help and Documentation

Version 7.0, July 2021

1. Introduction
2. Input files
2.1. Upload files
2.2. VOSA file format
2.3. Single object
2.4. Manage files
2.5. Archiving
2.6. Filters
3. Objects
3.1. Coordinates
3.2. Distances
3.3. Extinction
4. Build SEDs
4.1. VO photometry
4.2. SED
4.3. Excess
5. Analysis
5.1. Model Fit
5.2. Bayes analysis
5.3. Template Fit
5.4. Templates Bayes
5.5. Binary Fit
5.6. HR diagram
5.7. Upper Limits
5.8. Statistics
6. Save results
6.1. Download
6.2. SAMP
6.3. References
6.4. Log file
6.5. Plots
7. VOSA Architecture
8. Phys. Constants
9. FAQ
10. Use Case
11. Quality
11.1. Stellar libraries
11.2. VO photometry
12. Credits
12.1. VOSA
12.2. Th. Spectra
12.3. Templates
12.4. Isochrones
12.5. VO Photometry
12.6. Coordinates
12.7. Distances
12.8. Dereddening
12.9. Extinction
13. Helpdesk
14. About
. Excess calculation
. Total flux calculation
. VOphot quality info

Use Case: From SED fitting to Age estimation. The case of Collinder 69

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Obtaining photometry from the VO.

We have the option of consulting some VO catalogues to look for more photometry for the objects in our sample. In order to do that, we enter the "VO Phot" tab.

You can choose among several catalogues. Only the closest result will be shown in the results table. Thus, it does not make sense to use a large search radius; it only will result in a longer response time. In this case, we fix all the search radius to 5 arcsecs for each catalogue and click in the "Query selected services" button.

When the search is finished we see that some data have been found in three catalogs: SDSS, 2MASS and WISE, and these data are incorporated to our objects SEDs. Some of them (several of the ones corresponding to WISE.W4) are only upper limits, and they will not be used in the fits.

Now we could go to the "SED" tab to inspect (and, eventually, edit) the final SEDs for our objects.

You can see the information for each photometric data point. For instance, you see here that, for each of the 2MASS points, VOSA has averaged the user value (provided by us in the input file) and the one obtained from the 2MASS catalogue (in this case, this does not produce any effect because both values are identical).

We could make changes here, exclude some points, etc. But we are happy with the final SEDs so we will go to the next workflow step.


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