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arXiv · 2202.02329

Measuring the Total Ultraviolet Light from Galaxy Clusters at z=0.5-1.6: The Balance of Obscured and Unobscured Star-Formation

Jed McKinney·Vandana Ramakrishnan·Kyoung-Soo Lee·Alexandra Pope·Stacey Alberts·Yi-Kuan Chiang·Roxana Popescu
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Abstract

Combined observations from UV to IR wavelengths are necessary to fully account for the star-formation in galaxy clusters. Low mass (log M/Msun<10) galaxies are typically not individualy detected, particularly at higher redshifts (z~1-2) where galaxy clusters are undergoing rapid transitions from hosting mostly active, dust-obscured star-forming galaxies to quiescent, passive galaxies. To account for these undetected galaxies, we measure the total light emerging from GALEX/NUV stacks of galaxy clusters between z=0.5-1.6. Combined with existing measurements from Spitzer, WISE, and Herschel, we study the average UV through far-infrared (IR) spectral energy distribution (SED) of clusters. From the SEDs, we measure the total stellar mass and amount of dust-obscured and unobscured star-formation arising from all cluster-member galaxies, including the low mass population. The relative fraction of unobscured star-formation we observe in the UV is consistent with what is observed in field galaxies. There is tentative evidence for lower than expected unobscured star-formation at z~0.5, which may arise from rapid redshift evolution in the low mass quenching efficiency in clusters reported by other studies. Finally, the GALEX data places strong constraints on derived stellar-to-halo mass ratios at z<1 which anti-correlate with the total halo mass, consistent with trends found from local X-ray observations of clusters. The data exhibit steeper slopes than implementations of the cluster star-formation efficiency in semi-analytical models.

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Jed McKinney, Vandana Ramakrishnan, Kyoung-Soo Lee, Alexandra Pope, Stacey Alberts, Yi-Kuan Chiang, Roxana Popescu. 2022-02-04. Measuring the Total Ultraviolet Light from Galaxy Clusters at z=0.5-1.6: The Balance of Obscured and Unobscured Star-Formation. https://doi.org/10.3847/1538-4357%2Fac5110

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