2021ApJ...906...32Z -
Astrophys. J., 906, 32-32 (2021/January-1)
Strong Mg II and Fe II absorbers at 2.2 < z < 6.0.
ZOU S., JIANG L., SHEN Y., WU J., BANADOS E., FAN X., HO L.C., RIECHERS D.A., VENEMANS B., VESTERGAARD M., WALTER F., WANG F., WILLOTT C.J., JOSHI R., WU X.-B. and YANG J.
Abstract (from CDS):
We present a study of strong intervening absorption systems in the near-IR spectra of 31 luminous quasars at z > 5.7. The quasar spectra were obtained with Gemini GNIRS that provide continuous wavelength coverage from ∼0.9 to ∼2.5 µm. We detect 32 strong Mg II doublet absorbers with rest-frame equivalent width Wr(λ2796) > 1.0 Å at 2.2 < z < 6.0. Each Mg II absorber is confirmed by at least two associated Fe II absorption lines in the rest-frame wavelength range of ∼1600-2600 Å. We find that the comoving line density (dN/dX) of the strong Fe II-bearing Mg II absorbers decreases toward higher redshift at z > 3, consistent with previous studies. Compared with strong Mg II absorbers detected in damped Lyα systems at 2 < z < 4, our absorbers are potentially less saturated and show much larger rest-frame velocity widths. This suggests that the gas traced by our absorbers are potentially affected by galactic superwinds. We analyze the Hubble Space Telescope near-IR images of the quasars and identify possible associated galaxies for our strong absorbers. There are a maximum of two galaxy candidates found within 5'' radius of each absorber. The median F105W-band magnitude of these galaxy candidates is 24.8 mag, which is fainter than the L* galaxy luminosity at z ∼ 4. By using our observed dN/dX of strong Mg II absorbers and galaxy candidates median luminosity, we suggest that at high redshift, strong Mg II absorbers tend to have a more disturbed environment but smaller halo size than that at z < 1.
Abstract Copyright:
© 2021. The Author(s). Published by the American Astronomical Society.
Journal keyword(s):
Circumgalactic medium - Extragalactic astronomy - Quasar absorption line spectroscopy
Simbad objects:
31
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