Illustris Mock Deep Fields
Created by Gregory Snyder, Space Telescope Science Institute
On MAST HLSP:
- Website : https://archive.stsci.edu/prepds/illustris/
- Files like: https://archive.stsci.edu/hlsps/illustris/mag30-fielda-11-10_images/hlsp_misty_illustris_jwst-nircam_mag30-fielda-11-10_f200w_v1_lightcone.fits
- DOI : 10.17909/T98385
Files with names:
On Central Storage at STScI:
Acknowledgements. These are based on the Illustris Project hydrodynamical simulations:
- Lightcone image presented by: Vogelsberger et al. 2014 (Nature)
- Data release paper and documentation: http://illustris-project.org ; Nelson et al. 2015
- Lightcone application for hydro sims described by: Snyder et al. 2017
- Mock HST and JWST machinery supported by HST#13887
Contents, geometry, and selection:
The filenames indicate the mission, instrument, and filter combination of each image. The geometry/selection of these three fields is derived from the three ``Thin'' lightcones defined in Snyder et al. (2017), for example mag30-fielda-11-10_v1 corresponds to Field A (Thin) from that paper. The string "mag30" refers to the selection of Illustris subhalos included in the mock image. For these files, the selection is based on the rest-frame g-band apparent magnitude of the source, such that g < 30.0.
FITS files contain the following HDUs:
- "IMAGE_NOPSF": Raw image without PSF or noise. Header documented below.
- "SimulationAssumptions": URL links to Illustris documentation and API.
- "MockDataAssumptions": Header contains code and parameter choices for creating mock images.
- "IMAGE_PSF" : [Optional] Same image, now convolved with model PSF from TinyTim or WebbPSF.
- "MODELPSF" : [Optional] The PSF model at the same pixel scale as HDU 3 "IMAGE_PSF".
- "Catalog" : Lightcone Catalog, containing intrinsic simulation info, including galaxy ID numbers, image positions, and other info.
- "CatalogDocumentation": Strings containing explainers of catalog columns (same as below)
In HDU 0-"IMAGE_NOPSF", the header contains the following useful cards, for example:
FILTER = 'F160W ' / filter
PIXSIZE = 0.06 / arcsec
UNIT = 'nanoJanskies' / per pixel
ABZP = 31.40006562228223 / AB mag zeropoint
PHOTFNU = 1.52E-07 / Jy; approx flux[Jy] at 1 count/sec
EXTNAME = 'IMAGE_NOPSF'
DOI = 'https://doi.org/10.1093/mnras/stx487'
AUTHOR = 'Gregory F. Snyder'
PAPER = 'Snyder et al. 2017, MNRAS, 468, 207'
DATE = '2017-05-04T15:00:38.186163'
MISSION = 'HST ' / Mission/telescope
INSTR = 'WFC3 ' / Instrument
HIERARCH TELESCOPE = 'HST ' / Mission/telescope
HIERARCH INSTRUMENT = 'WFC3 ' / Instrument
ALLFIL = 'hst-wfc3_f160w'
IMTYPE = 'Survey ' / type of image source
REDSHIFT= '0.5-20 ' / Redshift of object or survey
These values, especially PHOTFNU, are highly approximate and should be confirmed by the user using an ETC before applying to any analyses.
For HDUs 3-4, I produced these only for HST and JWST filters, as I have not yet fully propagated the WFIRST filters and PSF characteristics. These might be a good test bed for "in-situ" data simulation methods. Also it might make sense to wait for the hardware to stabilize a bit more before fully installing these assumptions in a pipeline.
For HDU 5, here is the column documentation:
- 'snapshot' Illustris snapshot number
- 'SubfindID' Illustris subhalo Subfind ID number
- 'ra_deg' arbitrary right ascension in degrees
- 'dec_deg' arbitrary declination in degrees
- 'ra_kpc' arbitrary x offset in physical kpc at true redshift
- 'dec_kpc' arbitrary y offset in physical kpc at true redshift
- 'ra_kpc_inferred' same as previous but for inferred redshift
- 'dec_kpc_inferred' --
- 'true_z' true cosmological redshift
- 'inferred_z' inferred cosmological redshift (true z + peculiar v/c)
- 'peculiar_z' peculiar v/c
- 'true_kpc_per_arcsec' kpc per arcsec at true redshift
- 'X_cmpc' galaxy X position in observer frame [comoving Mpc]
- 'Y_cmpc' galaxy Y position in observer frame [comoving Mpc]
- 'Z_cmpc' galaxy Z position in observer frame [comoving Mpc]
- 'ADD_cmpc' angular diameter distance at true redshift [comoving Mpc]
- 'ADD_cmpc_inferred' angular diameter distance at inferred redshift [comoving Mpc]
- 'snapshot_z' redshift of Illustris snapshot from which this subhalo is drawn
- 'geometric_z' estimated redshift at the comoving distance in the center of the lightcone path through this snapshot
- 'cylinder_number' index of snapshot repetition for this subhalo
- 'mstar_msun_rad' stellar mass in 2X stellar half-mass radius [Msun]
- 'mgas_msun_rad' gas mass in 2X stellar half-mass radius [Msun]
- 'subhalo_mass_msun' total mass in subhalo [Msun]
- 'bhmass_msun_rad' supermassive black hole mass in 2X stellar half-mass radius [Msun]
- 'mbary_msun_rad' total baryon mass in 2X stellar half-mass radius [Msun]
- 'sfr_msunperyr_rad' SFR in 2X stellar half-mass radius [Msun]
- 'bhrate_code' supermassive black hole accretion rate in code units (see data release docs)
- 'camX_mpc' galaxy X position in camera frame [physical Mpc]
- 'camY_mpc' galaxy Y position in camera frame [physical Mpc]
- 'camZ_mpc' galaxy Z position in camera frame [physical Mpc]
- 'g_AB_absmag' rest-frame SDSS-g AB absolute magnitude
- 'r_AB_absmag' rest-frame SDSS-r AB absolute magnitude
- 'i_AB_absmag' rest-frame SDSS-i AB absolute magnitude
- 'z_AB_absmag' rest-frame SDSS-z AB absolute magnitude
- 'v_kms_camX' transverse x velocity [km/s]
- 'v_kms_camY' transverse y velocity [km/s]
- 'v_kms_camZ' line-of-sight (peculiar) velocity [km/s]
- 'v_kms_hubble' true cosmological expansion velocity [km/s]
- 'g_AB_appmag' rest-frame SDSS-g AB apparent magnitude
- 'sim' simulation name (e.g., 'Illustris-1')
- 'snap' Illustris snapshot number (same as 'snapshot')
- 'sfid' Illustris subhalo Subfind ID number (same as 'SubfindID')
- 'z' true cosmological redshift (same as 'true_z')
- 'RA' same as 'ra_deg'
- 'DEC' same as 'dec_deg'
- 'origin_i' Internal variable describing the image array location to place the origin of this galaxy's image [Internal-- does not describe final image]
- 'origin_j' Internal variable describing the image array location to place the origin of this galaxy's image [Internal-- does not describe final image]
- 'pos_i' position of this subhalo in array rows [it appears that (pos_j,pos_i) is the correct placement in Python terms] [Internal-- does not describe final image]
- 'pos_j' position of this subhalo in array columns [it appears that (pos_j,pos_i) is the correct placement in Python terms] [Internal-- does not describe final image]
- 'pixsize_arcsec' pixel size of image [Arcsec-- Internal--does not describe final image]
- 'final_fov_arcsec' final field-of-view of image [Arcsec]
- 'full_npix' total number of pixels across image [Internal-- does not describe final image]
- 'this_npix' number of pixels in this galaxy's sub-image [Internal-- does not describe final image]
- 'this_fov_kpc' field-of-view of this galaxy's image in physical kpc
- 'halfmassrad_factor' factor describing this galaxy's field of view in units of its stellar half-mass radius
- 'nrays' number of rays used to render this galaxy's image
- 'run_dir' internal run directory for locating this galaxy's sub-image
- 'success' whether or not this galaxy is rendered in the final image (should all be True; Falses were dropped from this table before saving)
- 'new_i' position of galaxy in image pixel units [final version-- use this one] [it appears that (pos_j,pos_i) is the correct placement in Python terms]
- 'new_j' position of galaxy in image pixel units [final version-- use this one] [it appears that (pos_j,pos_i) is the correct placement in Python terms]
- 'AB_absmag_jwst-nircam_f200w' (example name only) observed-frame perfectly measured total absolute magnitude in this filter for this galaxy [AB units]