Mission Overview

Physics at High Angular resolution in Nearby GalaxieS - JWST (PHANGS-JWST)

Primary Investigators:  Janice C. Lee, Karin Sandstrom, Adam Leroy, Eva Schinnerer, David Thilker, Kirsten Larson

HLSP Authors:  Thomas Williams, Oleg Egorov, Erik Rosolowsky, Adam Leroy, Eric Emsellem, David Thilker, Franceso Belfiore, Jessica Sutter, Karin Sandstrom, Janice C. Lee

Released:  2023-12-15

Updated:  2023-12-15

Primary Reference(s):  Lee et al. 2023, Williams et al. (in prep)

DOI:  10.17909/ew88-jt15

Citations:  See ADS Statistics

Read Me

Source Data:

 
PHANGS_JWST_Collage.png
This collection of images from the NASA/ESA/CSA James Webb Space Telescope shows 19 face-on spiral galaxies captured by NIRCam and MIRI.
Credit:  NASA, ESA, CSA, STScI, Janice Lee (STScI), Thomas Williams (Oxford), PHANGS Team
Acknowledgement:  Elizabeth Wheatley (STScI)

Overview

The PHANGS program is building a panchromatic dataset to enable the multi-phase, multi-scale study of star formation across nearby spiral galaxies.  PHANGS combines Atacama Large Millimeter/submillimeter Array (ALMA) CO(2-1) mapping, Very Large Telescope/Multi Unit Spectroscopic Explorer (VLT/MUSE) optical spectroscopy, Hubble Space Telescope (HST) UV-optical imaging, and James Webb Space Telescope (JWST) infrared imaging among other supporting datasets.   PHANGS is using these data to study the star formation cycle and various phases of the interstellar medium.

Here, the team provides image products from their Cycle 1 Treasury survey for 19 galaxies. The dataset consists of 8 JWST bands from NIRCam and MIRI (F200W, F300M, F335M, F360M, F770W, F1000W, F1130W, F2100W) which trace star light, including deeply embedded clusters, as well as various polycyclic aromatic hydrocarbon (PAH) dust features and the underlying dust continuum.

DR1 - Image Release 1 (December 15, 2023)

Provides images in all 8 bands for the full sample of 19 galaxies (barring two failed mosaic tiles for NGC4321 and NGC4303, scheduled to be re-observed in Jan 2024). The data have been processed using the jwst_1147.pmap reference files, JWST pipeline version 1.12.4, and pjpipe version 1.0.2 (https://pjpipe.readthedocs.io/en/latest/), the PHANGS-JWST bespoke pipeline wrapper around the STScI pipeline. The team expects that overall, the absolute fluxes are good to around the 0.1MJy/sr level. The NIRCam to NIRCam alignment is generally very good (sub-pixel), and are well-aligned with PHANGS-HST imaging. The NIRCam to MIRI alignment is less good (with shifts up to around 0.1 arcsec in the worst case). As such, the team considers the DR1 data quality sufficient for aperture photometry and for analysis at resolutions beyond ~0.5 arcsec, but not for forced PSF photometry or color-color analysis at close to the native resolution. For galaxies with very bright centres, diffraction spikes from the PSF are persistent across the image. The team will be improving on these issues for future releases.

If you find other issues with this data release, please do not hesitate to get in touch with the PHANGS-JWST helpdesk <jwsthelp@phangs.groups.io>.

Complementary PHANGS Data From ALMA and MUSE

Associated ALMA and MUSE data are publicly available though the PHANGS CANFAR site or https://sites.google.com/view/phangs/home/data

Complementary PHANGS Data from HST

Images:  https://archive.stsci.edu/hlsp/phangs/phangs-hst

Catalogs:  https://archive.stsci.edu/hlsp/phangs/phangs-cat

Data Products Description

Data file naming convention:

hlsp_phangs-jwst_jwst_<ins>_<targ>_<filt>_<ver>_<type>.fits

where:

  • <ins> is the JWST instrument that was used to collect the data (e.g. "miri" or "nircam")

  • <targ> is the target galaxy's name (e.g. "ic5332" or "ngc7496")

  • <filt> is the corresponding filter used to collect the data (e.g. "f360m" or "f1000w")

  • <ver> is the version number of the released products (e.g. "v1p0p1")

  • <type> is the type of file, detailed below

Data file types:

_tweakback.tar.gz

The tweakback files are tarballs of individually corrected tiles, which are fully processed up to the final mosaic stage, and have absolute astrometric corrections back-propagated to them. They include the following extensions:

  1. SCI: 2-D data array containing the pixel values, in units of surface brightness (MJy/sr).

  2. ERR: 2-D data array containing uncertainty estimates for each pixel. These values are based on the combined VAR_POISSON and VAR_RNOISE data, given as standard deviation.

  3. DQ: 2-D data array containing DQ flags for each pixel.

  4. VAR_POISSON: 2-D data array containing the variance estimate for each pixel, based on Poisson noise only.

  5. VAR_RNOISE: 2-D data array containing the variance estimate for each pixel, based on read noise only.

  6. VAR_FLAT: 2-D data array containing the variance estimate for each pixel, based on uncertainty in the flat-field.

_img.fits

The image files are combined, astrometrically aligned, and flux anchored mosaics, and include the following two additional extensions:

  1. CON: 3-D context image, which encodes information about which input images contribute to a specific output pixel
  2. WHT: 2-D weight image giving the relative weight of the output pixels

 

FITS extensions in these files are standard for the JWST pipeline. 

Data Access

For JWST image products, there are different options for data access:

1. Download from the data table on the main page.

2. Through the MAST Portal (web-based, cross-mission search interface). Set the Provenance Name filter to PHANGS-JWST in the Portal Advanced Search to find all or individual images. If you want access to the tweakback files, select the files you want to download, click the "Add to Download Basket" icon, un-select minimum recommended products in the download basket menu that pops up, and then select the tweakback files that you want to download.

3. Via Astroquery (Python package to search for and download files from Python scripts you write). Set the Provenance Name filter to PHANGS-JWST.

  • A web-based interface for cross-mission searches of data at MAST or the Virtual Observatory
  • Search for and retrieve PHANGS-JWST data products programmatically.

Citations

Please remember to cite the appropriate paper(s) below and the DOI if you use these data in a published work. 

Note: These HLSP data products are licensed for use under CC BY 4.0.

References