Narrow absorption lines from intervening material in supernovae

II. Galaxy properties

¹ Instituto de Astrofisica e Ciências do Espaço, Faculdade de Ciências, Universidade de Lisboa, Ed. C8, Campo Grande, 1749-016 Lisbon, Portugal
² CENTRA, Instituto Superior Técnico, Universidade de Lisboa, Av. Rovisco Pais 1, 1049-001 Lisboa, Portugal
³ European Southern Observatory, Alonso de Córdova 3107, Casilla 19, Santiago, Chile
⁴ Institut d’Estudis Espacials de Catalunya (IEEC), Edifici RDIT, Campus UPC, 08860 Castelldefels (Barcelona), Spain
⁵ Institute of Space Sciences (ICE, CSIC), Campus UAB, Carrer de Can Magrans, s/n, 08193 Barcelona, Spain
⁶ School of Physics, Trinity College Dublin, The University of Dublin, Dublin 2, Ireland
⁷ Millennium Institute of Astrophysics MAS, Nuncio Monsenor Sotero Sanz 100, Off. 104, Providencia, Santiago, Chile
⁸ School of Physics and Astronomy, University of Southampton, Southampton, SO17 1BJ, UK
⁹ Department of Applied Physics, School of Engineering, University of Cádiz, Campus of Puerto Real, 11519 Cádiz, Spain
¹⁰ Instituto de Astrofísica de Andalucía - CSIC, Apdo 3004, 18080 Granada, Spain
¹¹ Tuorla Observatory, Department of Physics and Astronomy, University of Turku, 20014 Turku, Finland
¹² European University Cyprus, Diogenes Street, Engomi, 1516 Nicosia, Cyprus

^★ Corresponding authors: gongsale@gmail.com; cgutierrez@ice.csic.es

Received: 3 March 2025
Accepted: 17 June 2025

Abstract

The interstellar medium (ISM) has a number of tracers such as the NaI Dλλ 5890, 5896 absorption lines that are evident in the spectra of galaxies but also in those of individual astrophysical sources such as stars, novae, or quasars. Here, we investigate narrow absorption features in the spectra of nearby supernovae (SNe) and compare them to local (<0.5 kpc) and global host galaxy properties. With a large and heterogeneous sample of spectra, we are able to recover the known relations of ISM with galaxy properties: larger columns of ISM gas are found in environments that are more massive, more actively star-forming, younger, and viewed from a more inclined angle. Most trends are stronger for local properties than global properties, and we find that the ISM column density decreases exponentially with the offset from the host galaxy centre, as expected for a gas distribution following an exponential radial profile. We also confirm trends for the velocity of galactic outflows increasing with radius. The current study demonstrates the capability of individual light sources to serve as ubiquitous tracers of ISM properties across various environments and galaxies.