The new Hubble Spectroscopic Legacy Archive (HSLA) provides coadded spectra of individual targets that have been observed with the Cosmic Origins Spectrograph (COS) and the Space Telescope Imaging Spectrograph (STIS) over their operating lifetime.
HSLA uses data available in the Mikulski Archive for Space Telescopes (MAST). It automatically produces coadds whenever new data become publicly available or when there is newly recalibrated data. HSLA defines individual targets by their associated coordinates, accounting for proper motions, and uses SIMBAD, NED and the Phase II observing proposals to obtain astronomical classifications for each object.
Coadded spectra are produced for each observing mode. In the case of COS far-ultraviolet observations there is one coadded spectrum for each lifetime position (LP). Additionally, a spectrum spanning the entire wavelength range covered by the observations is produced by abutting the spectra from a selection of individual modes.
For each individual target, HSLA also provides a human-readable metadata file with key information that can be used in searches or for further exploration of the data. The HSLA project also makes the code used for coadding spectra publicly available along with several other tools (using Jupyter notebooks) for custom coaddition required in special cases.
In this report we will describe the main components of HSLA and provide a brief description of how the data and metadata can be accessed.
Ravi Sankrit, John Debes, Matthew Burger, Van Dixon, Anna Payne, Leonardo Dos Santos, Thomas Wevers, Travis Fischer, Peter Forshay, Svea Hernandez, Robert Jedrzejewski, Rich Kidwell, Lauren Miller, Marc Rafelski, David Rodriguez, Robert Swaters, Dan Welty, Sara Anderson, Thomas Bair, Joleen Carlberg, Brian Charlow, Andrew Cortese, Tracy Ellis, Ben Falk, Scott Fleming, Elaine Frazer, Syed Gilani, Alec Hirschauer, Talya Kelley, Tim Kimball, Jennifer Kotler, Adrian Lucy, Sunita Malla, Christopher Rahmani, Fred Romelfanger, Kate Rowlands, Lisa Sherbert
Comments: 35 pages, 10 figures
Subjects: Instrumentation and Methods for Astrophysics (astro-ph.IM)
Report number: Instrument Science Report COS 2025-18
Cite as: arXiv:2605.04167 [astro-ph.IM] (or arXiv:2605.04167v1 [astro-ph.IM] for this version)
https://doi.org/10.48550/arXiv.2605.04167
Focus to learn more
Submission history
From: Van Dixon
[v1] Tue, 5 May 2026 18:03:32 UTC (3,293 KB)
https://arxiv.org/abs/2605.04167
Astrobiology, Astronomy, Astrochemistry, exoplanet,
