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Finding Quasars

Finding quasars suitable for measuring in the near ultraviolet proves difficult from the start. One can start looking and searching for papers that measured quasars fitting the requirements, but this becomes exhausting quickly.

The Right Source

The Right Parameters

When one looks at the interface on the aforementioned website, one can see in the top left corner the parameters button (three horizontal bars). The parameters that were chosen are: Spectral Range, Signal-to-Noise Ratio (SNR), Data Collection and Instrument. After selecting these, the first parameter that needs to be set is the data collection. This is due to the use of a special data collection in this project. The UVES SQUAD or UVES Spectral Quasar Absorption Database is a data base solely consisting of quasar observations with the UVES (Ultraviolet and Visual Echelle Spectrograph). Now after this, the spectral range can be set to UV, the instrument can be set to UVES and the signal-to-noise ratio can be set to the highest level and later to lower levels.[2]

The UVES instrument has a covered wavelength of about 300 – 500 nm.[1] The data base covers quasars that have a red-shift of z = 0 up to z = 5.[3]

Some Available Data Sets

The data base only has four quasar data sets available with the SNR at its highest level of over 100. When choosing a SNR of over 30, there are 84 sets available. [2] The number of data sets should now be enough for this project.

Quasar Data Sets

The Quasar data sets below are presented in the following way: Quasar Location || Signal-to-Noise Ratio || Spectral Range (nm) || Link. These are only some of the available data sets, more can be found in the ESO Science Portal.

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  J051707-441055 || 155.4 ||  304.4 – 1043 || Link

 J081331+254503 || 109.1 || 304.5 – 665.7 || Link

  J024008-230915 || 104.4 ||  304.4 – 1043 || Link

  J094253-110426 || 113.4 ||   304.4 – 1043 || Link

  J110325-264515 ||   97.0 ||  304.5 – 665.7 || Link

  J112442-170517 ||   94.3 ||   304.7 – 1043 || Link

  J222006-280323 ||   88.4 ||   304.6 – 1043 || Link

  J014333-391700 ||   84.3 ||   304.7 – 1043 || Link

  J000448-415728 ||   84.2 ||   304.6 – 1043 || Link

  J135038-251216 ||   81.0 ||   304.3 – 1043 || Link

 J133335+164903 ||   80.8 ||   304.5 – 1043 || Link

  J015327-431137 ||   79.4 ||   304.2 – 1043 || Link

  J212912-153841 ||   78.8 ||   323.4 – 1043 || Link

  J042214-384452 ||   74.0 ||   323.3 – 1043 || Link

  J000344-232355 ||   72.2 ||   304.7 – 1043 || Link

   J011143-350300 ||   71.5 ||   304.6 – 1043 || Link

​

Sources

  1. UVES Instrument Description: https://www.eso.org/sci/facilities/paranal/instruments/uves/inst.html#:~:text=UVES%20is%20a%20two%2Darm,to%20use%20dichroic%20beam%20splitters. (01.10.22, 12:22)

  2. ESO Science Portal with Settings: https://archive.eso.org/scienceportal/home?data_release_date=*:2019-03-21&data_collection=UVES_SQUAD&sort=-pi.keyword,-obs_date&s=P%2FDSS2%2Fcolor&f=180&fc=-1,-1&cs=J2000&av=true&ac=false&c=8,9,10,12,13,14,15,16,17,18&mt=true&dts=true&at=150.025582453,-34.32782535 (01.10.22, 12:22)

  3. UVES SQUAD Info: https://archive.eso.org/cms/eso-archive-news/the-uves-spectral-quasar-absorption-database--squad--data-releas.html (01.10.22, 12:22)

The right source needed to find a larger number of quasar data sets proved to be:

https://archive.eso.org/scienceportal/home

This archive consists of processed telescope data from the ESO observatory at La Silla Paranal Observatory.[2]

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