\ GMRT COSMOS 325 MHz catalog
\ Tisanic et al. (2019)
\ -------------------
\  Basic data info
\ -------------------
\  Catalog date: 24-Sep-2019
\  Source extractor: BLOBCAT v1.2 (http://blobcat.sourceforge.net/)
\  Observations: 45 h with the GMRT at 325 MHz, under project 07SCB01, single pointing
\  Data reduction: SPAM Pipeline (Intema et al. 2017)
\  Median rms noise in the COSMOS 2 sq.deg.: 97 uJy/beam
\  Resolution: 10.8x9.5 arcsec2
\  Resolved criteria: TOTAL/PEAK > 1+3.58*SNR^(-1.13)
\ -------------------
\  Catalog info
\ -------------------
\  The catalog contains sources selected down to a 5 sigma (sigma~97 uJy/beam) threshold. 
\  The data were reduced using the SPAM pipeline, and imaged at a resolution of 10.8x9.5 arcsec2.
\  Following Intema et al. (2017), primary beam correction was applied to the pointing.
\  Blobcat was used to extract sources down to 5 sigma.
\  Sources considered resolved by the TOTAL/PEAK > 1+3.58*SNR^(-1.13) criterion.
\ -------------------
\  Columns
\ -------------------
\  Col  Col_name   Units      Type      Nulls    Description
\   1   ID          /         long      /        ID of the source
\   2   ra         deg        float     /        J2000 RA coordinate
\   3   dec        deg        float     /        J2000 DEC coordinate
\   4   PEAK       uJy/beam   float     -99.0    Peak flux density
\   5   PEAK_ERR   uJy/beam   float     -99.0    Error of the peak flux density
\   6   TOTAL      uJy        float     -99.0    Total flux density
\   7   TOTAL_ERR  uJy        float     -99.0    Error of the total flux density
\   8   SNR        /          float     -99.0    Signal-to-noise ratio
\   9   RMS        uJy/beam   float     /        Local RMS noise at the source position
\   10  RESOLVED   /          char      /        Resolved flag (1 if resolved, 0 if unresolved)
\   11  MULTI      /          char      /        Multicomponent flag (=1 if multicomponent)
\   12  MULTI_N    /          integer   /        Number of multicomponents if MULIT=1
\ -------------------

\ GMRT COSMOS 610 MHz catalog
\ Tisanic et al. (2019)
\ -------------------
\  Basic data info
\ -------------------
\  Catalog date: 24-Sep-2019
\  Source extractor: BLOBCAT v1.2 (http://blobcat.sourceforge.net/)
\  Observations: 86 h with the GMRT at 608 MHz, under project 11HRK01, 19 pointings
\  Data reduction: SPAM Pipeline (Intema et al. 2017)
\  Median rms noise in the COSMOS 2 sq.deg.: 39 uJy/beam
\  Resolution: 5.6 x 3.9 arcsec2
\  Resolved criteria: TOTAL/PEAK > 1+1.26*SNR^(-0.76)
\ -------------------
\  Catalog info
\ -------------------
\  The catalog contains sources selected down to a 5 sigma (sigma~39 uJy/beam) threshold. 
\  The data were reduced using the SPAM pipeline, and imaged at a resolution of 5.6x3.9 arcsec2.
\  Following Intema et al. (2017), primary beam correction and the average pointing error
\  corrections were applied to each pointing prior to mosaicing.
\  Blobcat was used to extract sources down to 5 sigma.
\  Sources considered resolved by the TOTAL/PEAK > 1+1.26*SNR^(-0.76) criterion.
\
\  Note of caution !!!
\  1. For sources detected at both GMRT and VLA frequencies, there seems to be a deficit in flux 
\     computed at 610 MHz based on the VLA fluxes. This correction is appropriate for some of the 
\     sources, while blindly applying a 20% correction of the total flux induces overcorrection in 
\     others, as indicated by a large spread in the flux deficit histograms, which persists even 
\     if using only high-SNR sources.
\  2. The flux offset is different when computed based on the 1.4 GHz catalog and when computed  
\     using the 3 GHz catalog, indicating complications due to complex spectral shapes.
\  3. There is discrepancy between source counts around 600 MHz for various fields, with source 
\     count ratios varying up to ~20% between surveys below 10 mJy.
\  4. By looking at source counts the effect might be flux-dependent, but this analysis cannot  
\     be easily extended to all of the sources in the catalog since it can be reliably computed  
\     only between 1 mJy and 10 mJy, a flux range limited by cosmic variance at large-flux end  
\     and completeness effects at the low-flux end.
\  5. The flux offset effect might be positionally dependent, but simple exclusion of pointings 
\     did not  yield a specific pointing which produces these offsets. This would indicate that
\     a simple correction of the total flux would be a significant overcorrection if the 
\     correction is needed only for one  part of the map.
\  
\  While increasing fluxes for a small sample of individual sources is not without precedent
\  (Kolokythas+15), considering points 1-5, we advise caution in applying a similar correction 
\  to the whole catalog and instead model the errors of the total flux by having an independent 
\  20% additional error contribution.
\  
\  In summary,  the errors of the total flux reported in the catalog are increased by an 
\  independent 20% additional error contribution.
\ -------------------

For more information, see Tisanic et al. (2019),
https://ui.adsabs.harvard.edu/abs/2019A%26A...621A.139T/abstract