Primary Investigators: Danielle Berg,John Chisholm, Bethan James,Tim Heckman, Crystal Martin,Dan Stark
HLSP Website Authors: Danielle Berg, Bethan James, Meaghan McDonald, Teagan King
Released: 2022年03月15日
Updated: 2024年09月23日
Primary Reference(s): Berg et al. 2022, James et al. 2022
DOI: 10.17909/m3fq-jj25
Citations: See ADS Statistics
Source Data:
Final co-added absorption UV spectra from CLASSY observations. Vertical lines denote the following lines: blue = ISM, orange dashed = nebular, green dashed = wind.
Final co-added emission FUV spectra from CLASSY observations. Vertical lines denote the following lines: blue = ISM, orange dashed = nebular, green dashed = wind.
Far-UV spectra are fundamental to our understanding of star-forming galaxies, providing a unique window on massive stellar populations, chemical evolution, feedback processes, and reionization. The launch of the James Webb Space Telescope (JWST) and construction of the extremely large telescopes (ELTs) will soon usher in a new era, pushing the UV spectroscopic frontier to z~15-20. The success of these future endeavors hinges on a comprehensive understanding of the massive star populations and interstellar medium (ISM) gas conditions that power the observed UV spectral features. This requires the level of detail that is only possible in local galaxies.
The COS Legacy Spectroscopic SurveY (CLASSY) is a treasury survey that builds on the Hubble Space Telescope (HST) archive to construct the first high-quality, high-resolution far-ultraviolet (far-UV) spectral database of 45 nearby star-forming galaxies. The survey combines 177 orbits of archival observations with 135 new orbits (312 total orbits) of HST observations, or more than 600 total spectral images taken with the Cosmic Origins Spectrograph (COS). The CLASSY Treasury sample contains 45 star-forming galaxies selected to span similar properties as seen at high redshift, with a large range of masses, metallicities, ionization parameters, and densities, but enhanced star formation rates. The CLASSY spectral atlas contains a suite of emission and absorption features that enable investigations of the massive stellar population properties, the physical properties of large-scale outflows that regulate star formation, and the chemical abundance patterns of the gas and stars. Further, CLASSY will improve the diagnostic power of the rest-frame UV lines for use by future JWST/ELT surveys, providing a long-lasting legacy to the astronomical community for decades to come.
The main objective of CLASSY is to use FUV spectra to unify stellar and gas-phase physics, allowing a holistic understanding of massive stars as the drivers of the gaseous evolution of star-forming galaxies. Naturally, the pursuit of this goal will produce a number of additional HLSPs beyond the coadded spectra that will be useful to the astronomical community. Therefore, the enduring value and utility of CLASSY will reside in these state-of-the-art HLSPs products.
Summary of Planned CLASSY Deliverables:
CLASSY spectral atlas
Compiled ancillary data
CLASSY stellar continuum fits
Database of emission and absorption feature properties
Database of Lyα emission profile fits
Database of tailored photoionization models
Database of nebular properties
UV Diagnostic Tools
Database of tailored chemical evolution models
Database of feedback properties
Predictive tools of inferred LyC escape fractions %of ionizing photons
Improved stellar models and prescriptions
User-friendly CLASSY tutorials on interacting with and utilizing the HLSPs
HST/COS NUV acquisition images for the CLASSY sample are shown in blue, overlaid on top of the red-yellow SDSS r-band images (when available, see Berg+2021 for exceptions). The 2.5” COS aperture used for the UV spectra are shown as blue circles, closely matching the SDSS 3” optical aperture in orange.
Pos: 00:21:01 +00:52:48
Redshift: 0.098393
log M★: 9.09 M☉
log SFR: 1.07 yr-1
Metallicity: 0.30 Z/Z☉
An image of the galaxy plotted by sky coordinates RA and dec. The galaxy is centered with yellow denoting its brighter parts and purple denoting its fainter parts.
Pos: 00:36:53 -33:33:17
Redshift: 0.020598
log M★: 9.14 Msol
log SFR: 1.01 yr-1
Metallicity: 0.33 Z/Z☉
An image of the galaxy plotted by sky coordinates RA and dec. The galaxy is centered with yellow denoting its brighter parts and purple denoting its fainter parts.
Pos: 01:27:36 -06:19:36
Redshift: 0.005400
log M★: 8.74 Msol
log SFR: -0.75 yr-1
Metallicity: 0.10 Z/Z☉
An image of the galaxy plotted by sky coordinates RA and dec. The galaxy is centered with yellow denoting its brighter parts and purple denoting its fainter parts.
Pos: 01:44:41 +04:53:25
Redshift: 0.005200
log M★: 7.65 Msol
log SFR: -0.81 yr-1
Metallicity: 0.12 Z/Z☉
J0144+0453_postage.png
Pos: 03:37:44 -05:02:39
Redshift: 0.013520
log M★: 7.06 Msol
log SFR: -0.32 yr-1
Metallicity: 0.06 Z/Z☉
An image of the galaxy plotted by sky coordinates RA and dec. The galaxy is centered with yellow denoting its brighter parts and purple denoting its fainter parts.
Pos: 04:05:20-36:48:59
Redshift: 0.002800
log M★: 6.61 Msol
log SFR: -1.81 yr-1
Metallicity: 0.02 Z/Z☉
An image of the galaxy plotted by sky coordinates RA and dec. The galaxy is centered with yellow denoting its brighter parts and purple denoting its fainter parts.
Pos: 08:08:44+39:48:53
Redshift: 0.091230
log M★: 9.12 Msol
log SFR: 1.26 yr-1
Metallicity: 1.20 Z/Z☉
An image of the galaxy plotted by sky coordinates RA and dec. The galaxy is centered with yellow denoting its brighter parts and purple denoting its fainter parts.
Pos: 08:23:55+28:06:22
Redshift: 0.047223
log M★: 9.38 Msol
log SFR: 1.48 yr-1
Metallicity: 0.39 Z/Z☉
An image of the galaxy plotted by sky coordinates RA and dec. The galaxy is centered with yellow denoting its brighter parts and purple denoting its fainter parts.
Pos: 09:26:00+44:27:37
Redshift: 0.180667
log M★: 8.76 Msol
log SFR: 1.03 yr-1
Metallicity: 0.25 Z/Z☉
An image of the galaxy plotted by sky coordinates RA and dec. The galaxy is centered with yellow denoting its brighter parts and purple denoting its fainter parts.
Pos: 09:34:02+55:14:28
Redshift: 0.002500
log M★: 6.27 Msol
log SFR: -1.52 yr-1
Metallicity: 0.02 Z/Z☉
An image of the galaxy plotted by sky coordinates RA and dec. The galaxy is centered with yellow denoting its brighter parts and purple denoting its fainter parts.
Pos: 09:38:13+54:28:25
Redshift: 0.102102
log M★: 9.15 Msol
log SFR: 1.05 yr-1
Metallicity: 0.36 Z/Z☉
An image of the galaxy plotted by sky coordinates RA and dec. The galaxy is centered with yellow denoting its brighter parts and purple denoting its fainter parts.
Pos: 09:40:13+29:35:30
Redshift: 0.001675
log M★: 6.71 Msol
log SFR: -2.01 yr-1
Metallicity: 0.09 Z/Z☉
An image of the galaxy plotted by sky coordinates RA and dec. The galaxy is centered with yellow denoting its brighter parts and purple denoting its fainter parts.
Pos: 09:42:53+35:47:26
Redshift: 0.014857
log M★: 7.56 Msol
log SFR: -0.76 yr-1
Metallicity: 0.28 Z/Z☉
An image of the galaxy plotted by sky coordinates RA and dec. The galaxy is centered with yellow denoting its brighter parts and purple denoting its fainter parts.
Pos: 09:44:02-00:38:32
Redshift: 0.004776
log M★: 6.83 Msol
log SFR: -0.78 yr-1
Metallicity: 0.14 Z/Z☉
An image of the galaxy plotted by sky coordinates RA and dec. The galaxy is centered with yellow denoting its brighter parts and purple denoting its fainter parts.
Pos: 09:44:26+34:42:08
Redshift: 0.020046
log M★: 8.19 Msol
log SFR: -0.01 yr-1
Metallicity: 0.09 Z/Z☉
An image of the galaxy plotted by sky coordinates RA and dec. The galaxy is centered with yellow denoting its brighter parts and purple denoting its fainter parts.
Pos: 10:16:24+37:54:46
Redshift: 0.003879
log M★: 6.72 Msol
log SFR: -1.17 yr-1
Metallicity: 0.07 Z/Z☉
An image of the galaxy plotted by sky coordinates RA and dec. The galaxy is centered with yellow denoting its brighter parts and purple denoting its fainter parts.
Pos: 10:24:29+05:24:51
Redshift: 0.033191
log M★: 7.89 Msol
log SFR: 0.21 yr-1
Metallicity: 0.14 Z/Z☉
An image of the galaxy plotted by sky coordinates RA and dec. The galaxy is centered with yellow denoting its brighter parts and purple denoting its fainter parts.
Pos: 10:25:48+36:22:58
Redshift: 0.126500
log M★: 8.87 Msol
log SFR: 1.04 yr-1
Metallicity: 0.28 Z/Z☉
An image of the galaxy plotted by sky coordinates RA and dec. The galaxy is centered with yellow denoting its brighter parts and purple denoting its fainter parts.
Pos: 10:44:58+03:53:13
Redshift: 0.012870
log M★: 6.80 Msol
log SFR: -0.59 yr-1
Metallicity: 0.06 Z/Z☉
An image of the galaxy plotted by sky coordinates RA and dec. The galaxy is centered with yellow denoting its brighter parts and purple denoting its fainter parts.
Pos: 11:05:08+44:44:47
Redshift: 0.021540
log M★: 8.98 Msol
log SFR: 0.69 yr-1
Metallicity: 0.35 Z/Z☉
An image of the galaxy plotted by sky coordinates RA and dec. The galaxy is centered with yellow denoting its brighter parts and purple denoting its fainter parts.
Pos: 11:12:44+55:03:47
Redshift: 0.020598
log M★: 9.59 Msol
log SFR: 1.60 yr-1
Metallicity: 0.58 Z/Z☉
An image of the galaxy plotted by sky coordinates RA and dec. The galaxy is centered with yellow denoting its brighter parts and purple denoting its fainter parts.
Pos: 11:19:34+51:30:12
Redshift: 0.004458
log M★: 6.77 Msol
log SFR: -1.58 yr-1
Metallicity: 0.08 Z/Z☉
An image of the galaxy plotted by sky coordinates RA and dec. The galaxy is centered with yellow denoting its brighter parts and purple denoting its fainter parts.
Pos: 11:29:14+20:34:52
Redshift: 0.004703
log M★: 8.09 Msol
log SFR: -0.37 yr-1
Metallicity: 0.39 Z/Z☉
An image of the galaxy plotted by sky coordinates RA and dec. The galaxy is centered with yellow denoting its brighter parts and purple denoting its fainter parts.
Pos: 11:32:03+57:22:36
Redshift: 0.005041
log M★: 7.31 Msol
log SFR: -1.07 yr-1
Metallicity: 0.08 Z/Z☉
An image of the galaxy plotted by sky coordinates RA and dec. The galaxy is centered with yellow denoting its brighter parts and purple denoting its fainter parts.
Pos: 11:32:35+14:11:30
Redshift: 0.017637
log M★: 8.68 Msol
log SFR: 0.44 yr-1
Metallicity: 0.36 Z/Z☉
An image of the galaxy plotted by sky coordinates RA and dec. The galaxy is centered with yellow denoting its brighter parts and purple denoting its fainter parts.
Pos: 11:44:22+40:12:21
Redshift: 0.126947
log M★: 9.89 Msol
log SFR: 1.51 yr-1
Metallicity: 0.55 Z/Z☉
An image of the galaxy plotted by sky coordinates RA and dec. The galaxy is centered with yellow denoting its brighter parts and purple denoting its fainter parts.
Pos: 11:48:27+25:46:12
Redshift: 0.045117
log M★: 8.14 Msol
log SFR: 0.53 yr-1
Metallicity: 0.18 Z/Z☉
An image of the galaxy plotted by sky coordinates RA and dec. The galaxy is centered with yellow denoting its brighter parts and purple denoting its fainter parts.
Pos: 11:50:03+15:01:23
Redshift: 0.002448
log M★: 6.84 Msol
log SFR: -1.33 yr-1
Metallicity: 0.28 Z/Z☉
An image of the galaxy plotted by sky coordinates RA and dec. The galaxy is centered with yellow denoting its brighter parts and purple denoting its fainter parts.
Pos: 11:57:32+32:20:30
Redshift: 0.010970
log M★: 9.04 Msol
log SFR: 0.97 yr-1
Metallicity: 0.55 Z/Z☉
An image of the galaxy plotted by sky coordinates RA and dec. The galaxy is centered with yellow denoting its brighter parts and purple denoting its fainter parts.
Pos: 12:00:33+13:43:08
Redshift: 0.066750
log M★: 8.12 Msol
log SFR: 0.75 yr-1
Metallicity: 0.37 Z/Z☉
An image of the galaxy plotted by sky coordinates RA and dec. The galaxy is centered with yellow denoting its brighter parts and purple denoting its fainter parts.
Pos: 12:25:05+61:09:11
Redshift: 0.002341
log M★: 7.12 Msol
log SFR: -1.08 yr-1
Metallicity: 0.19 Z/Z☉
An image of the galaxy plotted by sky coordinates RA and dec. The galaxy is centered with yellow denoting its brighter parts and purple denoting its fainter parts.
Pos: 12:53:06-03:12:59
Redshift: 0.022723
log M★: 7.65 Msol
log SFR: 0.56 yr-1
Metallicity: 0.23 Z/Z☉
An image of the galaxy plotted by sky coordinates RA and dec. The galaxy is centered with yellow denoting its brighter parts and purple denoting its fainter parts.
Pos: 13:14:47+34:52:60
Redshift: 0.002885
log M★: 7.56 Msol
log SFR: -0.67 yr-1
Metallicity: 0.37 Z/Z☉
An image of the galaxy plotted by sky coordinates RA and dec. The galaxy is centered with yellow denoting its brighter parts and purple denoting its fainter parts.
Pos: 13:23:48-01:32:52
Redshift: 0.022464
log M★: 6.31 Msol
log SFR: -0.72 yr-1
Metallicity: 0.10 Z/Z☉
An image of the galaxy plotted by sky coordinates RA and dec. The galaxy is centered with yellow denoting its brighter parts and purple denoting its fainter parts.
Pos: 13:59:51+57:26:23
Redshift: 0.033829
log M★: 8.41 Msol
log SFR: 0.42 yr-1
Metallicity: 0.19 Z/Z☉
An image of the galaxy plotted by sky coordinates RA and dec. The galaxy is centered with yellow denoting its brighter parts and purple denoting its fainter parts.
Pos: 14:16:13+12:23:40
Redshift: 0.123156
log M★: 9.59 Msol
log SFR: 1.57 yr-1
Metallicity: 0.69 Z/Z☉
An image of the galaxy plotted by sky coordinates RA and dec. The galaxy is centered with yellow denoting its brighter parts and purple denoting its fainter parts.
Pos: 14:18:51+21:02:40
Redshift: 0.008550
log M★: 6.22 Msol
log SFR: -1.13 yr-1
Metallicity: 0.11 Z/Z☉
An image of the galaxy plotted by sky coordinates RA and dec. The galaxy is centered with yellow denoting its brighter parts and purple denoting its fainter parts.
Pos: 14:28:56+16:53:39
Redshift: 0.181666
log M★: 9.56 Msol
log SFR: 1.22 yr-1
Metallicity: 0.44 Z/Z☉
An image of the galaxy plotted by sky coordinates RA and dec. The galaxy is centered with yellow denoting its brighter parts and purple denoting its fainter parts.
Pos: 14:29:47+06:43:35
Redshift: 0.173502
log M★: 8.80 Msol
log SFR: 1.42 yr-1
Metallicity: 0.26 Z/Z☉
An image of the galaxy plotted by sky coordinates RA and dec. The galaxy is centered with yellow denoting its brighter parts and purple denoting its fainter parts.
Pos: 14:44:11+42:37:36
Redshift: 0.002300
log M★: 6.48 Msol
log SFR: -1.94 yr-1
Metallicity: 0.09 Z/Z☉
An image of the galaxy plotted by sky coordinates RA and dec. The galaxy is centered with yellow denoting its brighter parts and purple denoting its fainter parts.
Pos: 14:48:05-01:10:58
Redshift: 0.027412
log M★: 7.61 Msol
log SFR: 0.39 yr-1
Metallicity: 0.28 Z/Z☉
An image of the galaxy plotted by sky coordinates RA and dec. The galaxy is centered with yellow denoting its brighter parts and purple denoting its fainter parts.
Pos: 15:21:42+07:59:22
Redshift: 0.094261
log M★: 9.00 Msol
log SFR: 0.95 yr-1
Metallicity: 0.42 Z/Z☉
An image of the galaxy plotted by sky coordinates RA and dec. The galaxy is centered with yellow denoting its brighter parts and purple denoting its fainter parts.
Pos: 15:25:22+07:57:20
Redshift: 0.075791
log M★: 10.10 Msol
log SFR: 1.00 yr-1
Metallicity: 0.44 Z/Z☉
An image of the galaxy plotted by sky coordinates RA and dec. The galaxy is centered with yellow denoting its brighter parts and purple denoting its fainter parts.
Pos: 15:45:43+08:58:01
Redshift: 0.037724
log M★: 7.52 Msol
log SFR: 0.37 yr-1
Metallicity: 0.11 Z/Z☉
An image of the galaxy plotted by sky coordinates RA and dec. The galaxy is centered with yellow denoting its brighter parts and purple denoting its fainter parts.
Pos: 16:12:46+08:17:01
Redshift: 0.149143
log M★: 9.78 Msol
log SFR: 1.58 yr-1
Metallicity: 0.31 Z/Z☉
An image of the galaxy plotted by sky coordinates RA and dec. The galaxy is centered with yellow denoting its brighter parts and purple denoting its fainter parts.
CLASSY was constructed to provide a critical legacy data set to the community that can be used for many years to come. Under this umbrella, we provide the research community with several high level science products (HLSPs) for each CLASSY target, which are listed below. The primary deliverable is co-added UV spectra for each target (derived from CLASSY program GO-15840 and archival programs) at multiple spectral resolutions (see Berg+2021 and James+2021 for more details). For more information on data products and their respective file extensions, see the CLASSY Data Products page.
Data file naming convention:
hlsp_classy_hst_cos_<target>_multi_v1_<ext>
where:
File types:
| _coadded.fits | Co-added UV spectra |
CLASSY data products are available to download below. To download a tarball of HLSPs use the ‘Download All CLASSY data’ button. To download a subset of CLASSY products based on target properties, observation parameters, or file type, click the ‘MAST Query Tool’ button.
AccessJupyter Notebook tutorials to interact with CLASSY HLSPs using Python. Click the links below to view the notebook in your browser, or download the notebook to your local computer and work through the steps on your own. Check back for additional notebook releases as more CLASSY HLSPs are released.
NOTE: This notebook was created and contributed by the CLASSY team. MAST makes this notebook available "as-is" and does not take responsibility for its maintenance.
Plot multi-grating co-added spectra using a Jupyter Notebook
Interactive HST/COS CLASSY spectra, combining archival and new FUV G130M+G160M+G185M observations. Note that chip gaps are indicated by blank spaces and that Milky Way absorption features and geocoronal lines are still present. By zooming in on different regions of the spectrum, you will see different stellar, ISM, and nebular features. Some of the common features are marked by colored bands and are labeled when you hover. You can click on the different types of spectral features in the legend to turn them on and off.
For any use of CLASSY data:
CLASSY Website
CLASSY I: Berg et al. 2022
CLASSY II: James et al. 2022
CLASSY III: Xu et al. 2022
CLASSY IV: Mingozzi et al. 2022
CLASSY V: Arellano-Córdova et al. 2022
CLASSY VI: Xu et al. 2023
CLASSY VII: Hu et al. 2023
CLASSY VIII: Mingozzi et al. 2024
For use of the coadded spectra HLSPs:
CLASSY I: Berg et al. 2022
CLASSY II: James et al. 2022
For use of the stellar continuum fits HLSPs:
CLASSY III: Xu et al. 2022
CLASSY IV: Mingozzi et al. 2022
For use of the UV emission lines HLSPs:
CLASSY IV: Mingozzi et al. 2022
CLASSY VIII: Mingozzi et al. 2024
For use of the optical emission lines HLSPs:
CLASSY IV: Mingozzi et al. 2022
CLASSY V: Arellano-Córdova et al. 2022
For use of the LyA HLSPs:
CLASSY VII: Hu et al. 2023
For use of the nebular properties HLSPs:
CLASSY IV: Mingozzi et al. 2022
For use of the UV Diagnostic HLSPs:
CLASSY VIII: Mingozzi et al. 2024
For use of the photoionization model HLSPs:
TBD
For use of the chemical evolution HLSPs:
CLASSY IV: Arellano-Cordova et al. 2024
For use of the feedback properties HLSPs:
TBD
Note: These HLSP data products are licensed for use under CC BY 4.0.
List of CLASSY publications:
List of CLASSY publications in NASA/ADS
We extend our gratitude to the Lorentz Center for useful discussions during the “Characterizing Galaxies with Spectroscopy with a view for JWST” 2017 workshop that led to the formation of the CLASSY collaboration and survey.
We are sincerely grateful to the MAST team at STScI and their expertise in developing the MAST Search Tool for use with CLASSY data.