The Spitzer Spectroscopic Data Fusion - Merged Spectroscopic Redshift Catalogs in Spitzer Fields

<p>The Spitzer Spectroscopic Data Fusion merges&nbsp;miscellaneous spectroscopic information available within "popular" extragalactic survey fields.</p> <p>Last Updated on 20 March 2025 - <a href="https://zenodo.org/record/6368347">https://zenodo.org/record/6368347</a> - <a href="https://www.mattiavaccari.net/df/specz">https://www.mattiavaccari.net/df/specz</a></p> <p>Based on the Spitzer Data Fusion Project - <a href="https://doi.org/10.5281/zenodo.7850783">https://doi.org/10.5281/zenodo.7850783</a>&nbsp;-&nbsp;<a href="https://mattiavaccari.net/df">https://mattiavaccari.net/df</a></p> <p>Merged Spec-Z ("specz-merged") catalogs merge miscellaneous spec-z information available&nbsp;within a given field. Different spec-z catalogs available within a given field are merged&nbsp;(using a search radius of 1.0 arcsec), and for sources with multiple spec-z measurements&nbsp;the most reliable one is chosen following the (largely arbitrarily) assumed order of decreasing&nbsp;reliability indicated below for each field. If CAT1,...,CATN spec-z catalogs are available&nbsp;in a given field, Z_1 from CAT1 (i.e. NED) is adopted as "best" redshift (i.e. ZBEST),&nbsp;if available, otherwise Z_2 from CAT_2 is adopted if available, and so on up to Z_N and CAT_N.&nbsp;In using ZBEST it's thus important to bear in mind that this is not necessarily actually the&nbsp;"best" redshift for science purposes, and in particular that the choice of NED as CAT1 is often&nbsp;not ideal. However, Z_1,...,Z_N are included to allow users to define the "best" redshift based&nbsp;on their science needs when multiple redshift estimates are available for a given source.&nbsp;ZFLAG specifies which catalog is providing the ZBEST value according to the CATN number below.&nbsp;ZCLASS is meant to provide further info about the class/quality of the spectroscopic redshift&nbsp;measurement, but for the time being is not populated and is simply a copy of ZFLAG.&nbsp;ZWHERE is an additional binary/bit flag indicating in which of the N catalogs each source&nbsp;was given a spec-z estimate in. ZWHERE will e.g. be 2^0=1 if a redshift if available <em>only</em>&nbsp;from CAT_1, whereas it will be 2^0+2^1=3 if a redshift is available *only* from CAT1 and CAT2,<br>so that a source with a redshift available from all catalogues will have ZWHERE=2^0+...+2^n.</p> <p>See AAAREADME.SPECZ-MERGED within the ZIP archive for further information.</p>