Details

Autor(en) / Beteiligte

• Verhamme, A
• Garel, T
• Ventou, E
• Contini, T
• Bouché, N
• Herenz, EC
• Richard, J
• Bacon, R
• Schmidt, KB
• Maseda, M
• Marino, RA
• Brinchmann, J
• Cantalupo, S
• Caruana, J
• Clément, B
• Diener, C
• Drake, AB
• Hashimoto, T
• Inami, H
• Kerutt, J
• Kollatschny, W
• Leclercq, F
• Patrício, V
• Schaye, J
• Wisotzki, L
• Zabl, J

Titel

Recovering the systemic redshift of galaxies from their Lyman alpha line profile

Ist Teil von

• Monthly notices of the Royal Astronomical Society, 2018-07, Vol.478 (1), p.L60-L65

Ort / Verlag

Oxford Journals

Erscheinungsjahr

2018

Quelle

Elektronische Zeitschriftenbibliothek - Freely accessible e-journals

Beschreibungen/Notizen

• Abstract The Lyman alpha (Ly α) line of Hydrogen is a prominent feature in the spectra of star-forming galaxies, usually redshifted by a few hundreds of km s−1 compared to the systemic redshift. This large offset hampers follow-up surveys, galaxy pair statistics, and correlations with quasar absorption lines when only Ly α is available. We propose diagnostics that can be used to recover the systemic redshift directly from the properties of the Ly α line profile. We use spectroscopic observations of Ly α emitters for which a precise measurement of the systemic redshift is available. Our sample contains 13 sources detected between z ≈ 3 and z ≈ 6 as part of various multi-unit spectroscopic explorer guaranteed time observations. We also include a compilation of spectroscopic Ly α data from the literature spanning a wide redshift range (z ≈ 0–8). First, restricting our analysis to double-peaked Ly α spectra, we find a tight correlation between the velocity offset of the red peak with respect to the systemic redshift, $V_{\rm peak}^{\rm red}$, and the separation of the peaks. Secondly, we find a correlation between $V_{\rm peak}^{\rm red}$ and the full width at half-maximum of the Ly α line. Fitting formulas to estimate systemic redshifts of galaxies with an accuracy of ≤100 km s−1, when only the Ly α emission line is available, are given for the two methods.