What does strong ionized-carbon emission reveal inside the SSA22 Lyman-alpha blob?

ALMA spectroscopy probes the interstellar medium of galaxies embedded in SSA22-LAB1 at redshift 3.1.

ALMA Reveals Strong [C II] Emission in a Galaxy Embedded in a Giant Lyα Blob at z = 3.1

ALMA Reveals Strong [C II] Emission in a Galaxy Embedded in a Giant Lyα Blob at z = 3.1. Umehata, Hideki; Matsuda, Yuichi; Tamura, Yoichi; Kohno, Kotaro; Smail, Ian; Ivison, R. J.; Steidel, Charles C.; Chapman, Scott C.; Geach, James E.; Hayes, Matthew; Nagao, Tohru; Ao, Yiping; Kawabe, Ryohei; Yun, Min S.; Hatsukade, Bunyo; Kubo, Mariko; Kato, Yuta; Saito, Tomoki; Ikarashi, Soh; Nakanishi, Kouichiro; Lee, Minju; Izumi, Takuma; Mori, Masao; Ouchi, Masami, Astrophysical Journal, 834, L16 (2017).

arXiv:1701.00043 Publication · DOI

Approach

The observations search for the 158-micrometre [C II] line and compare its strength with infrared emission and the [N II] line.

Main result

[C II] is detected in LAB1-ALMA3 at redshift 3.0993. Its strength and high carbon-to-nitrogen line ratio suggest unusual gas conditions.

Scientific implications

Photodissociation regions, low metallicity or shocks offer possible explanations linking galaxy gas physics with a giant Lyman-alpha nebula.

Scope and limitations

The proposed excitation mechanisms are alternatives. These observations do not establish a unique explanation or a causal link to the extended nebula.