#Deep field catalogues & images — ELAIS-N1

## Readme file

The following README file provides a description of the various files released for the Lockman Hole in this data release.

- lockman_README.txt : README file

## Radio data and raw catalogues

The following files provide the radio data, plus the raw source and Gaussian catalogues produced by PyBDSF (prior to any source association) Further datasets and catalogues may be available on request (e.g. catalogues per observation date, polarisation data). For further details see Tasse et al 2021 ( https://ui.adsabs.harvard.edu/abs/2020arXiv201108328T/abstract ). 

- lockman_radio_image.fits : Primary beam corrected radio image (crop)
- lockman_radio_rms_image.fits : Radio RMS image
- lockman_pybdsf_source.fits : Initial PyBDSF source list
- lockman_pybdsf_gaussian.fits : Initial PyBDSF Gaussian component list
- lockman_columns_pybdsf_source.md : Column description file for pybdsf_source.fits

## Optical images and catalogues

The following files provide the multi-wavelength data in three key bands, plus the full combined optical/IR catalogue presented by Kondapally et al. (2021) ( https://ui.adsabs.harvard.edu/abs/2020arXiv201108201K/abstract ). Details on the creation of the multi-band mosaics, the photometry catalogues, and the recommended quality/flag cuts are outlined in Section 3 of Kondapally et al. (2021) and in the README . All magnitudes provided are in the AB system. For further information regarding the multi-wavelength data see Kondapally et al or contact Rohit Kondapally (rohitk@roe.ac.uk). Raw photometry is provided in 8 circular apertures, and in addition, photometry in our recommended aperture sizes, corrected for both aperture and Galactic extinction effects is also provided. The multi-band mosaics have a magnitude zero-point of 30mag in the AB system.

- lockman_image_rband.fits : SpARCS r-band mosaic
- lockman_image_4.5band.fits : Spitzer SWIRE 4.5 band mosaic
- lockman_image_Kband.fits : UKIDSS-DXS K-band image (from DR10)
- lockman_optIR_catalogue_full.fits : The full combined chi2 detected optical/IR catalogue
- lockman_columns_optIR_catalogue_full.md : Column description file for optIR_catalogue_full.fits

## Photometric redshifts and science-ready multi-wavelength data

 The following files provide the photometric redshifts as provided in Duncan et al. (2020: https://doi.org/10.1051/0004-6361/202038809 ). Details of the photometric redshift and stellar mass (limited to z < 1.5) estimation are outlined in the paper, as well as guidance on the parameter space within which these values can be trusted. Additional information regarding the definition of the photometric redshift columns can also be found in Section 4 of Duncan et al. (2019a: https://doi.org/10.1051/0004-6361/201833562 ). Columns providing Herschel far-IR information for the full optical catalogs are provided by the Herschel Extragalactic Legacy Project (HELP; https://github.com/H-E-L-P/dmu_products ) - to we which refer the reader for additional information regarding methodology and column definition. The revised 24-500um flux information for the LOFAR source population (as provided in the final cross-matched catalogues below) is presented in McCheyne et al. (in prep.). Additionally, full panchromatic spectral energy distribution fitting for the LOFAR detected population that accounts for AGN contributions and far-IR emission will be presented separately in Best et al. (in prep.).

- lockman_optIR_catalogue_science_ready_photoz.fits : The science ready catalogues with photo-z, spec-z's and stellar masses (where available)
- lockman_columns_optIR_catalogue_science_ready_photoz.md : Columns description file for the optIR_catalogue_science_ready_photoz.fits

## Source-associated and cross-matched data

The following files provide the radio catalogues resulting from source association and cross-matching, as detailed in Section 4 of Kondapally et al. (2021) ( https://ui.adsabs.harvard.edu/abs/2020arXiv201108201K/abstract ). This process was carried out over the regions of the field with best-quality overlapping multi-wavelength data (see README for details of quality/flag cuts used). See Kondapally et al for further information.

- lockman_pybdsf_source_lr.fits : Initial PyBDSF source list with Likelihood Ratio only and workflow information
- lockman_final_cross_match_catalogue-v1.0.fits : Final cross-matched radio catalogue with key optical host galaxy properties
- lockman_final_component_catalogue-v1.0.fits : Final component radio catalogue, after source association and deblending
- lockman_columns_final_cross_match_catalogue.md : Column description file for final_cross_match_catalogue-v1.0.fits
- lockman_columns_final_component_catalogue.md : Column description file for final_component_catalogue-v1.0.fits

## Mask and MOC files

The following files provide nan-masked radio RMS images generated based on the coverage of the overlapping multi-wavelength data in the field and bright-star masking (based on both Spitzer and optical detections). The overlapping multi-wavelength coverage and the details of the bright-star mask generation are provided in Section 3 and Appendix B of Kondapally et al. (2021) ( https://ui.adsabs.harvard.edu/abs/2020arXiv201108201K/abstract ). The multi-order coverage (MOC) maps corresponding to the masks are also provided.

- lockman_rms_starmask_optical.fits : NaN masked radio RMS map with information about multi-wavelength overlap coverage and bright star masks (star masking based on --optical-- detections)
- lockman_rms_starmask_spitzer.fits : NaN masked radio RMS map with information about multi-wavelength overlap coverage and bright star masks (star masking based on --Spitzer-- detections)
- lockman_starmask_optical_MOC.fits : MOC file indicating star mask regions based on optical detections (conservative mask; use in rms_starmask_optical.fits)
- lockman_starmask_spitzer_MOC.fits : MOC file indicating star mask regions based on Spitzer detections (restrictive mask; use in rms_starmask_spitzer.fits)

## Source classification files

The following files provide the radio source classifications arising  from the SED fitting campaign for DR1 of the LoTSS Deep Fields. The files are described by Best et al. (2023) ( https://arxiv.org/abs/2305.05782 ).

- lockman_sed_photometry_dr1.fits : the input photometry used for the SED fitting
- lockman_classifications_dr1.fits : the key combined results of the SED fitting, with source classifications
- lockman_classifications_extended_dr1.fits : an extended version of the classifications containing various sub-classifications from each fitting code.
- lockman_classifications_README.txt : a description of the columns in the classifications files

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#### Note: The flag cuts are different for each field ####

##  Recommended flag cuts 
#############################
- These flag cuts are used for the radio-optical cross match during LR and LGZ

flag_clean != 3
FLAG_OVERLAP == 3
#############################


1. Bright star masking: Given by flag_clean. Two star masks are generated, based on optical catalogue detections (conservative) and Spitzer catalogue (optimistic) - see Kondapally+2021
	A MOC file for each of the two star masks are also provided - see README.txt for these MOC files.
   flag_clean defined as follows:
	- flag_clean = 1 : Sources not in optical or Spitzer star masked region (most conservative selection)
	- flag_clean = 2 : Sources only in the optical masked region
	- flag_clean = 3 : Sources in the Spitzer masked region

	## Note: radio-optical cross-matching is done for both flag_clean = 1 and flag_clean = 2 sources. But restriction to flag_clean = 1 is recommended for most science goals.
		 Users who use flag_clean = 2 should beware that multi-wavelength detections may not be complete in these regions, and the photometry may be less reliable.

2. Multi-wavelength overlap/coverage: Given by FLAG_OVERLAP and FLAG_OVERLAP for optical and radio sources; bit flag.
   FLAG_OVERLAP (_RADIO) are both defined as follows:
   		- FLAG_OVERLAP = 1 : Sources in the SpARCS r-band coverage only
		- FLAG_OVERLAP = 2 : Sources in the UKIDSS-DXS K-band coverage only

	## Note: radio-optical cross-matching is limited to FLAG_OVERLAP (_RADIO) == 3 i.e. sources in the overlapping coverage of all three surveys.

3. Radio-optical cross-match workflow flag: Given by FLAG_WORKFLOW. 
   FLAG_WORKFLOW:
	- FLAG_WORKFLOW == 1 : Accept LR-ID
	- FLAG_WORKFLOW == 2 : Sources sent to LGZ
	- FLAG_WORKFLOW = 3 or 4 : Sources sent to pre-filtering
	- FLAG_WORKFLOW == 5 : Sources sent to deblend workflow

        ## Note: Indicates where an initial PyBDSF source was sent to be classified NOT the final method by which the source was classified. E.g. a source initially sent to LGZ may then be sent to deblending workflow for final classification.
	## Note: LGZ ID found overwrites any LR-ID.

4. Survey and Filter names used in flux and magnitude column names, e.g. #band_flux_corr, #band_mag_corr where #band can be:
   SpARCS : u, g, r, z
   RCSLenS : g_rcs, r_rcs, i_rcs, z_rcs
   DXS : J, K
   SWIRE : ch1_swire, ch2_swire, ch3_swire, ch4_swire
   SERVS : ch1_servs, ch2_servs

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