Submillimeter Observations of CLASH 2882 and the Evolution of Dust in this Galaxy

TL;DR

This study combines millimeter and other wavelength observations to analyze the dust content and star formation history of the gravitationally lensed galaxy CLASH 2882 at z=0.99, revealing dust mass accumulation processes beyond supernova and AGB star production.

Contribution

It provides the first detailed spectral energy distribution of CLASH 2882, showing that most dust was accreted in dense interstellar medium phases, not solely produced by supernovae or AGB stars.

Findings

Dust mass exceeds maximum produced by supernovae and AGB stars.

Star formation rate is approximately 54 solar masses per year.

Most dust in the galaxy was accreted in dense ISM phases.

Abstract

Two millimeter observations of the MACS J1149.6+2223 cluster have detected a source that was consistent with the location of the lensed MACS1149-JD galaxy at z=9.6. A positive identification would have rendered this galaxy as the youngest dust forming galaxy in the universe. Follow up observation with the AzTEC 1.1 mm camera and the IRAM NOrthern Extended Millimeter Array (NOEMA) at 1.3 mm have not confirmed this association. In this paper we show that the NOEMA observations associate the 2 mm source with [PCB2012] 2882 ([PCB2012] 2882 is the NED-searchable name for this source.), source number 2882 in the Hubble Space Telescope ( HST) Cluster Lensing and Supernova (CLASH) catalog of MACS J1149.6+2223. This source, hereafter referred to as CLASH 2882, is a gravitationally lensed spiral galaxy at z=0.99. We combine the GISMO 2 mm and NOEMA 1.3 mm fluxes with other (rest frame) UV to far-IR observations to construct the full spectral energy distribution (SED) of this galaxy, and derive its star formation history, and stellar and interstellar dust content. The current star formation rate of the galaxy is 54/mu Msun yr-1, and its dust mass is about 5 10^7/mu Msun, where mu is the lensing magnification factor for this source, which has a mean value of 2.7. The inferred dust mass is higher than the maximum dust mass that can be produced by core collapse supernovae (CCSN) and evolved AGB stars. As with many other star forming galaxies, most of the dust mass in CLASH 2882 must have been accreted in the dense phases of the ISM.