Mission Overview
CANDELS NIRWL F160W Mosaics ("CANDELSNIRWL")
Primary Investigator: Kyle Finner
HLSP Authors: Kyle Finner, BoMee Lee, Ranga-Ram Chary, M. James Jee, Christopher Hirata, Giuseppe Congedo, Peter Taylor, Kim Hyeonghan
Released: 2024-03-26
Updated: 2024-03-26
Primary Reference(s): Finner et al. 2023
DOI: 10.17909/f6hb-ez10
Citations: See ADS Statistics
Source Data:
candelsnirwl astrometric offset
Astrometric offset distribution of the CANDELS mosaic and the NIRWL mosaic
Astrometric offset of the CANDELS Treasury Mosaics v1.0 (gray) and the mosaics produced in this work (blue) from the positions of stars in the proper motion–corrected Gaia catalog DR3. Vertical dashed (this work) and dotted (Treasury) lines mark the median astrometric offset. On average, the updated mosaics have an astrometric offset from the Gaia catalog of 0.02’’, a factor of several improvements compared to the Treasury mosaics.
Astrometric offset of star positions from Gaia DR3 in the COSMOS field
Astrometric offset of star positions from Gaia DR3 to the corresponding star positions in the CANDELS Treasury v1.0 image (Left) and the NIRWL image (Right). The circles represent the star positions from the Gaia DR3 catalog. The lines represent the magnitude and direction of the offset from the Gaia DR3 star positions to the star positions in the respective mosaic. The average astrometric offsets have been improved in the NIRWL image, and systematic variations have been reduced.
Astrometric offset of star positions from Gaia DR3 in the EGS field
Astrometric offset of star positions from Gaia DR3 to the corresponding star positions in the CANDELS Treasury v1.0 image (Left) and the NIRWL image (Right). The circles represent the star positions from the Gaia DR3 catalog. The lines represent the magnitude and direction of the offset from the Gaia DR3 star positions to the star positions in the respective mosaic. The average astrometric offsets have been improved in the NIRWL image, and systematic variations have been reduced.
Astrometric offset of star positions from Gaia DR3 in the GOODS-N field
Astrometric offset of star positions from Gaia DR3 to the corresponding star positions in the CANDELS Treasury v1.0 image (Left) and the NIRWL image (Right). The circles represent the star positions from the Gaia DR3 catalog. The lines represent the magnitude and direction of the offset from the Gaia DR3 star positions to the star positions in the respective mosaic. The average astrometric offsets have been improved in the NIRWL image, and systematic variations have been reduced.
Astrometric offset of star positions from Gaia DR3 in the GOODS-S field
Astrometric offset of star positions from Gaia DR3 to the corresponding star positions in the CANDELS Treasury v1.0 image (Left) and the NIRWL image (Right). The circles represent the star positions from the Gaia DR3 catalog. The lines represent the magnitude and direction of the offset from the Gaia DR3 star positions to the star positions in the respective mosaic. The average astrometric offsets have been improved in the NIRWL image, and systematic variations have been reduced.
Astrometric offset of star positions from Gaia DR3 in the UDS field
Astrometric offset of star positions from Gaia DR3 to the corresponding star positions in the CANDELS Treasury v1.0 image (Top) and the NIRWL image (Bottom). The circles represent the star positions from the Gaia DR3 catalog. The lines represent the magnitude and direction of the offset from the Gaia DR3 star positions to the star positions in the respective mosaic. The average astrometric offsets have been improved in the NIRWL image, and systematic variations have been reduced.
Overview
The NIRWL team has prepared new mosaics covering the CANDELS fields: The UltraDeep Survey (UDS), GOODS South (GS), GOODS North (GN), The Extended Groth Strip (EGS), and the Cosmological Evolution Survey (COSMOS) in the HST F160W filter. The mosaics are drizzled to a pixel scale of 0.05’’ using the Gaussian kernel. The mosaics are aligned to the Gaia DR3 catalog to ±0.02 arcsec. Proper motions were included when aligning the frames to Gaia DR3. These mosaics have been corrected for systematic astrometric misalignments found in previous versions of the CANDELS F160W mosaics.
These carefully aligned mosaics have been created to perform a weak lensing analysis and search for large-scale overdensities. The spatially and temporally varying PSF of each mosaic has been constructed from the individual frames and characterized in the team's primary paper, Finner et al. (2023). Systematic effects that can affect galaxy shape measurements on the NIRWL mosaics are investigated.
Data Products
Data file naming convention:
hlsp_candelsnirwl_hst_wfc3-ir_<field>_f160w_v1.0_<prodType>.fits
where:
- <field> is a CANDELS field, one of "uds", "gs", "gn", "egs", and "cosmos"
- <prodType> is one of "sci", "wht", or "rms".
Data file types:
| _sci.fits | Science image, the output of the Drizzle algorithm, and is in counts/s |
| _wht.fits | Weight image, the output of the Drizzle algorithm |
| _rms.fits | RMS image created by (weight image)-1/2 |
Data Access
All observations are available in the MAST Portal and astroquery. Set the 'Provenance Name' filter to CANDELSNIRWL in the Portal Advanced Search to match all observations. The weight and RMS images can be downloaded with their science image as a bundle or individually retrieved by selecting the download basket. The observations can also be retrieved programmatically using the astroquery.mast module. The code example below retrieves all products.
from astroquery.mast import Observations
all_obs = Observations.query_criteria(provenance_name="candelsnirwl")
data_products = Observations.get_product_list(all_obs)
Observations.download_products(data_products)
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A web-based interface for cross-mission searches of data at MAST or the Virtual Observatory
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Search for and retrieve CANDELSNIRWL data products programmatically.
