Mission Overview

Lyman-alpha Reference Sample (LARS)

 

Primary Investigators: Jens Melinder, Matthew Hayes, Göran Östlin

HLSP Authors: Jens Melinder

Released: 2023-07-24

Updated: 2023-07-24

Primary Reference(s): Melinder, et al. 2023

DOI: 10.17909/pbe1-m743

Citations: Melinder, et al. 2023 metrics

Read Me

Source Data:

 

Slideshow

Now showing slide 1 of 8

LARS-01

Color RGB composites of selected LARS galaxies. The stellar continuum (left panel) is derived from HST I-, B-, and U-band images (red, green, and blue channels, respectively). The right panel shows the emission in Hα (red), Lyα (blue), and stellar continuum in the FUV near Ly-α (green). The scale bar (lower left) has a length of 5 kpc.

LARS-05

Color RGB composites of selected LARS galaxies. The stellar continuum (left panel) is derived from HST I-, B-, and U-band images (red, green, and blue channels, respectively). The right panel shows the emission in Hα (red), Lyα (blue), and stellar continuum in the FUV near Ly-α (green). The scale bar (lower left) has a length of 5 kpc.

LARS 08

Color RGB composites of selected LARS galaxies. The stellar continuum (left panel) is derived from HST I-, B-, and U-band images (red, green, and blue channels, respectively). The right panel shows the emission in Hα (red), Lyα (blue), and stellar continuum in the FUV near Ly-α (green). The scale bar (lower left) has a length of 5 kpc.

LARS-14

Color RGB composites of selected LARS galaxies. The stellar continuum (left panel) is derived from HST I-, B-, and U-band images (red, green, and blue channels, respectively). The right panel shows the emission in Hα (red), Lyα (blue), and stellar continuum in the FUV near Ly-α (green). The scale bar (lower right) has a length of 5 kpc.

ELARS-01

Color RGB composites of selected LARS galaxies. The stellar continuum (left panel) is derived from HST I-, B-, and U-band images (red, green, and blue channels, respectively). The right panel shows the emission in Hα (red), Lyα (blue), and stellar continuum in the FUV near Ly-α (green). The scale bar (lower left) has a length of 5 kpc.

ELARS-07

Color RGB composites of selected LARS galaxies. The stellar continuum (left panel) is derived from HST I-, B-, and U-band images (red, green, and blue channels, respectively). The right panel shows the emission in Hα (red), Lyα (blue), and stellar continuum in the FUV near Ly-α (green). The scale bar (lower left) has a length of 5 kpc.

ELARS-10

Color RGB composites of selected LARS galaxies. The stellar continuum (left panel) is derived from HST I-, B-, and U-band images (red, green, and blue channels, respectively). The right panel shows the emission in Hα (red), Lyα (blue), and stellar continuum in the FUV near Ly-α (green). The scale bar (lower left) has a length of 5 kpc.

ELARS-23

Color RGB composites of selected LARS galaxies. The stellar continuum (left panel) is derived from HST I-, B-, and U-band images (red, green, and blue channels, respectively). The right panel shows the emission in Hα (red), Lyα (blue), and stellar continuum in the FUV near Ly-α (green). The scale bar (lower left) has a length of 5 kpc.

Overview

The Lyman-α Reference Sample (hereafter, LARS) collection consists of HST observations of 45 star-forming galaxies at redshifts 0.03–0.24. The products consist of reduced images, line and galaxy property maps, and tables of photometric measurements. The data used mainly come from the two LARS HST imaging programs (PIDs: 12310 and 13483). Various instruments (ACS/SBC, ACS/WFC, and WFC3/UVIS) and filters have been used to image the Lyman-α/Hα/Hβ emission and characterize the stellar populations. Apart from the reduced images the collection also contains maps of emission lines and of derived physical quantities such as stellar age, extinction, and mass for the galaxies. In addition the collection contains tables with global photometry of the galaxies and tables with surface brightness profiles for each galaxy.

Data Products

Data file naming convention:

hlsp_lars_hst_<instrument>_<targ>_<filter>_v1.0_<prodType>.<ext>

where:

  • <Instrument> is the name of the instrument/mode used for the observations, one of acs, acs-sbc, acs-wfc, wfc3, wfc3-uvis or a combination of these
  • <targ> is the LARS target identifier, such as elars01 or lars08
  • <filter> is the name of the filter used, such as: f125lp, f140lp, f150lp, f336w, f502n, f673n, f775w
  • <prodType> is the type of semantic content of the product (see below)
  • <ext> is the file extension type: one of fits (science) or png (previews)

Semantic content types:

drz Drizzle-combined science image
map Spatial map of physical quantities
preview Preview (RGB) image
tab Tables of photometric and physical quantities per target, as well as surface brightness profiles

Attributes of the images, maps, and tables of measurements are summarized below; consult the README and Melinder et al. (2023) for details of how the contents were prepared. 

Image Files

The calibrated input images from this survey were drizzle-combined, and the output images were sampled at a common scale of 0.04 arcsec/pix, aligned to a common image coordinate frame, and PSF-matched. Binned images were created using a Voronoi tesselation method with a limiting signal-to-noise ratio (SNR) of 10, and a maximum size of 1 arcsec2 (i.e., 252 pixels). The bluest stellar continuum filter was used to determine the binning pattern. Each FITS file contains 4 image extensions, with EXTNAME values as follows:

EXTNAME Description
SCI Science image
WHT Weight array for science image
SCI-BINNED Binned science image
WHT-BINNED Binned weight array
PROVENANCE Provenance of the images, i.e., which input data contributed to the final product

MAP Files

The map files include images of stellar continuum, as well as continuum- and background-subtracted line emission, and spatial distributions of derived physical quantities such as the star formation rate. Each FITS file contains 20 image extensions, distinguished by the EXTNAME keyword value. Extension numbers 1 through 10 are images of the physical quantities, and 11 through 20 are the corresponding standard-deviations of those quantities.

Table File

The table contains measurements of various physical quantities for each target. The FITS file is organized into 47 BINTABLE extensions, which are identified by the value of the EXTNAME keyword. The first extension is a table of global quantities (i.e., averaged over each galaxy), extensions 2 through 46 are radially-averaged profiles of these quantities for each galaxy, and the last extension is the PROVENANCE for these quantities.

Data Access

LARS images are available in the MAST Portal (web-based, cross-mission search interface) and Astroquery (Python package to search for and download files from Python scripts you write), and via the direct download table below. The maps and the measurements table are only available from the Direct Downloads section below. Set the Provenance Name filter to LARS in the Portal Advanced Search to find all or individual images.

from astroquery.mast import Observations
all_obs = Observations.query_criteria(provenance_name="LARS")
data_products = Observations.get_product_list(all_obs)
Observations.download_products(data_products)
  • A web-based interface for cross-mission searches of data at MAST or the Virtual Observatory
  • Search for and retrieve GLASS-JWST data products programmatically.

Direct Download

Access g-zipped tar files of the LARS images, maps, and previews from the table below, by target. The file sizes are between 76 and 130 MB. The measurements table file hlsp_lars_hst_wfc3-acs_multi_v1.0_tab.fits is also available.

LARS ID SDSS ID Common Name Files
LARS 01 SDSS-J132844.05+435550.5 Mrk 259

hlsp_lars_hst_multi_lars01_v1.0_allfiles.tgz

LARS 02

SDSS-J090704.88+532656.6 Shoc 240

hlsp_lars_hst_multi_lars02_v1.0_allfiles.tgz

LARS 03

SDSS-J131535.06+620728.6 Arp 238

hlsp_lars_hst_multi_lars03_v1.0_allfiles.tgz

LARS 04

SDSS-J130728.45+542652.3  

hlsp_lars_hst_multi_lars04_v1.0_allfiles.tgz

LARS 05

SDSS J135950.92+572622.9 Mrk 1486

hlsp_lars_hst_multi_lars05_v1.0_allfiles.tgz

LARS 06

SDSS-J154544.52+441551.8 KISSR 2019

hlsp_lars_hst_multi_lars06_v1.0_allfiles.tgz

LARS 07 SDSS-J131603.91+292254.0 IRAS F13136+2938

hlsp_lars_hst_multi_lars07_v1.0_allfiles.tgz

LARS 08 SDSS-J125013.50+073441.5  

hlsp_lars_hst_multi_lars08_v1.0_allfiles.tgz

LARS 09 SDSS-J082354.96+280621.6 IRAS 08208+2816

hlsp_lars_hst_multi_lars09_v1.0_allfiles.tgz

LARS 10 SDSS-J130141.52+292252.8 Mrk 0061

hlsp_lars_hst_multi_lars10_v1.0_allfiles.tgz

LARS 11 SDSS-J140347.22+062812.1  

hlsp_lars_hst_multi_lars11_v1.0_allfiles.tgz

LARS 12 SDSS J093813.44+542824.9 LEDA 27453

hlsp_lars_hst_multi_lars12_v1.0_allfiles.tgz

LARS 13 SDSS-J015028.39+130858.4 IRAS 01477+1254

hlsp_lars_hst_multi_lars013_v1.0_allfiles.tgz

LARS 14 SDSS-J092600.41+442736.1  

hlsp_lars_hst_multi_lars14_v1.0_allfiles.tgz

ELARS 01 SDSS-J161140.81+522727.0 NGC 6090 hlsp_lars_hst_multi_elars01_v1.0_allfiles.tgz
ELARS 02 SDSS-J132109.07+590605.3 Mrk 65

hlsp_lars_hst_multi_elars02_v1.0_allfiles.tgz

ELARS 03 SDSS-J114511.42+614230.6 UGC 06727

hlsp_lars_hst_multi_elars03_v1.0_allfiles.tgz

ELARS 04 SDSS-J172823.84+573243.4 NGC 6387

hlsp_lars_hst_multi_elars04_v1.0_allfiles.tgz

ELARS 05 SDSS-J110501.98+594103.5 SBS 1102+599A

hlsp_lars_hst_multi_elars05_v1.0_allfiles.tgz

ELARS 06 SDSS-J115840.58+645753.0  

hlsp_lars_hst_multi_elars06_v1.0_allfiles.tgz

ELARS 07 SDSS-J101242.97+613302.8  

hlsp_lars_hst_multi_elars07_v1.0_allfiles.tgz

ELARS 08 SDSS-J103020.91+611549.3  

hlsp_lars_hst_multi_elars08_v1.0_allfiles.tgz

ELARS 09 SDSS-J132734.70+664516.6  

hlsp_lars_hst_multi_elars09_v1.0_allfiles.tgz

ELARS 10 SDSS-J110504.41+593957.3 SBS 1102+599B

hlsp_lars_hst_multi_elars10_v1.0_allfiles.tgz

ELARS 11

SDSS-J092715.48+583654.4 MRK 1417

hlsp_lars_hst_multi_elars11_v1.0_allfiles.tgz

ELARS 12

SDSS-J130607.16+591302.4 SBS 1304+594

hlsp_lars_hst_multi_elars12_v1.0_allfiles.tgz

ELARS 13

SDSS-J105100.65+655940.5 VII Zw 348

hlsp_lars_hst_multi_elars13_v1.0_allfiles.tgz

ELARS 14

SDSS-J112722.07+604454.1 SBS 1124+610

hlsp_lars_hst_multi_elars14_v1.0_allfiles.tgz

ELARS 15

SDSS-J134437.82+611424.3 MCG +10-20-017

hlsp_lars_hst_multi_elars15_v1.0_allfiles.tgz

ELARS 16

SDSS-J135209.13+560631.4  

hlsp_lars_hst_multi_elars16_v1.0_allfiles.tgz

ELARS 17

SDSS-J102656.29+584941.6  

hlsp_lars_hst_multi_elars17_v1.0_allfiles.tgz

ELARS 18

SDSS-J152053.59+571122.1  

hlsp_lars_hst_multi_elars18_v1.0_allfiles.tgz

ELARS 19

SDSS-J120506.35+563330.9  

hlsp_lars_hst_multi_elars19_v1.0_allfiles.tgz

ELARS 20

SDSS-J133858.25+614957.6  

hlsp_lars_hst_multi_elars20_v1.0_allfiles.tgz

ELARS 21

SDSS-J141911.37+654946.3  

hlsp_lars_hst_multi_elars21_v1.0_allfiles.tgz

ELARS 22

SDSS-J170912.73+604950.0 SBS 1708+608

hlsp_lars_hst_multi_elars22_v1.0_allfiles.tgz

ELARS 23

SDSS-J144827.20+630210.4  

hlsp_lars_hst_multi_elars23_v1.0_allfiles.tgz

ELARS 24

SDSS-J144305.31+611838.6  

hlsp_lars_hst_multi_elars24_v1.0_allfiles.tgz

ELARS 25

SDSS-J101201.93+603720.3 KUG 1008+608

hlsp_lars_hst_multi_elars25_v1.0_allfiles.tgz

ELARS 26

SDSS-J115241.69+661827.2  

hlsp_lars_hst_multi_elars26_v1.0_allfiles.tgz

ELARS 27

SDSS-J150247.62+622018.9  

hlsp_lars_hst_multi_elars27_v1.0_allfiles.tgz

ELARS 28

SDSS-J115218.74+585657.0  

hlsp_lars_hst_multi_elars28_v1.0_allfiles.tgz

Tol 1214

  Tololo 1214-277

hlsp_lars_hst_multi_tol1214_v1.0_allfiles.tgz

Tol 1247

  Tololo 1247-232

hlsp_lars_hst_multi_tol1247_v1.0_allfiles.tgz

J 1156

SDSS-J115630.63+500822.1  

hlsp_lars_hst_multi_j1156_v1.0_allfiles.tgz

 

Citations

Be sure 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