Detection of the 158 micron [CII] Transition at z=1.3: Evidence for a Galaxy-Wide Starburst

TL;DR

This paper reports the detection of the 158 micron [CII] line in a hyperluminous starburst galaxy at z=1.3, revealing galaxy-wide starburst activity with properties similar to local starbursts.

Contribution

First detection of [CII] emission in a hyperluminous starburst galaxy at high redshift, providing insights into galaxy-wide star formation and PDR conditions.

Findings

[CII] line is bright and indicates intense starburst activity.

The galaxy's PDRs have high density and strong UV radiation fields.

The [CII]/FIR ratio suggests a scaled-up starburst nucleus.

Abstract

We report the detection of 158 micron [CII] fine-structure line emission from MIPS J142824.0+352619, a hyperluminous (L_IR ~ 10^13 L_sun) starburst galaxy at z=1.3. The line is bright, and corresponds to a fraction L_[CII]/L_FIR = 2 x 10^-3 of the far-IR (FIR) continuum. The [CII], CO, and FIR continuum emission may be modeled as arising from photodissociation regions (PDRs) that have a characteristic gas density of n ~ 10^4.2 cm^-3, and that are illuminated by a far-UV radiation field ~10^3.2 times more intense than the local interstellar radiation field. The mass in these PDRs accounts for approximately half of the molecular gas mass in this galaxy. The L_[CII]/L_FIR ratio is higher than observed in local ULIRGs or in the few high-redshift QSOs detected in [CII], but the L_[CII]/L_FIR and L_CO/L_FIR ratios are similar to the values seen in nearby starburst galaxies. This suggests that MIPS J142824.0+352619 is a scaled-up version of a starburst nucleus, with the burst extended over several kiloparsecs.