2025A&A...694A..67B -
Astronomy and Astrophysics, volume 694A67 (2025/2-1)
MusE GAs FLOw and Wind (MEGAFLOW) XII. Rationale and design of a Mg II survey of the cool circum-galactic medium with MUSE and UVES: The MEGAFLOW Survey.
BOUCHE N.F., WENDT M., ZABL J., CHERREY M., SCHROETTER I., LANGAN I., MUZAHID S., SCHAYE J., EPINAT B., WISOTZKI L., CONTINI T., RICHARD J., BACON R. and WEILBACHER P.M.
Abstract (from CDS):
We present the design, rationale, properties, and catalogues of the MusE Gas FLOw and Wind survey (MEGAFLOW) of cool gaseous halos of z ≃ 1.0 galaxies, using low-ionisation Mg II absorption systems. The survey consists of 22 quasar fields selected from the Sloan Digital Sky Survey (SDSS), including multiple (≥3) strong Mg II absorption lines over the redshift range of 0.3 < z < 1.5. Each quasar was observed with the Multi-Unit Spectroscopic Explorer (MUSE) and the Ultraviolet and Visual Echelle Spectrograph (UVES), for a total of 85 hours and 63 hours, respectively. The UVES data resulted in 127 Mg II absorption lines over 0.25 < z < 1.6, with a median rest-frame equivalent width (REW) 3σ limit of ≈0.05 Å. The MUSE data resulted in ∼2400 galaxies, of which 1403 are characterised by a redshift confidence of ZCONF > 1; this amounts to more than 60 galaxies per arcmin2. They were identified using a dual detection algorithm based on both continuum and emission line objects. The achieved [O II] 50% completeness is 3.7–0.6+0.8 × 10–18 erg s–1 cm–2 (corresponding to an SFR of > 0.01 M⊙ yr–1 at z = 1) using realistic mock [O II] emitters and the 50% completeness is mF775W ≈ 26 AB magnitudes for continuum sources. We find that (i) the fraction of [O II] emitting galaxies that have no continuum is ∼15%; (ii) the success rate in identifying at least one galaxy within 500 km s–1 and 100 kpc is ≈90% for Mg II absorptions with $ W_{\mathrm{r}}^{2796}\gtrsim0.5 $ Å; (iii) the mean number of galaxies per Mg II absorption is 2.9 ± 1.6 within the MUSE field-of-view; (iv) of the 80 Mg II systems at 0.3 < z < 1.5, 40 (20) have 1 (2) galaxies within 100 kpc, respectively; and, finally, (v) all but two host galaxies have stellar masses of M⋆ > 109 M⊙ and star formation rates of > 1 M⊙ yr–1.
Abstract Copyright:
© The Authors 2025
Journal keyword(s):
galaxies: evolution - galaxies: formation - intergalactic medium - quasars: absorption lines
Status at CDS
:
Large table(s) will be appraised for possible ingestion in VizieR.
Simbad objects:
22
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