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<i>Spitzer Planck Herschel</i> Infrared Cluster (SPHerIC) survey: Candidate galaxy clusters at 1.3 < <i>z</i> < 3 selected by high star-formation rate
摘要： There is a lack of large samples of spectroscopically confirmed clusters and protoclusters at high redshifts, z > 1.5. Discovering and characterizing distant (proto-)clusters is important for yielding insights into the formation of large-scale structure and on the physical processes responsible for regulating star-formation in galaxies in dense environments. The Spitzer Planck Herschel Infrared Cluster (SPHerIC) survey was initiated to identify these characteristically faint and dust-reddened sources during the epoch of their early assembly. We present Spitzer/IRAC observations of 82 galaxy (proto-)cluster candidates at 1.3 < zp < 3.0 that were vetted in a two step process: (1) using Planck to select by color those sources with the highest star-formation rates, and (2) using Herschel at higher resolution to separate out the individual red sources. The addition of the Spitzer data enables efficient detection of the central and massive brightest red cluster galaxies (BRCGs). We find that BRCGs are associated with highly significant, extended and crowded regions of IRAC sources which are more overdense than the field. This result corroborates our hypothesis that BRCGs within the Planck–Herschel sources trace some of the densest and actively star-forming proto-clusters in the early Universe. On the basis of a richness-mass proxy relation, we obtain an estimate of their mean masses which suggests our sample consists of some of the most massive clusters at z ≈ 2 and are the likely progenitors of the most massive clusters observed today.
关键词： galaxies: star formation,submillimeter: galaxies,infrared: galaxies,galaxies: evolution,galaxies: clusters: general,galaxies: high-redshift
更新于2025-09-23 15:23:52
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Revealing Dusty Supernovae in High-redshift (Ultra)Luminous Infrared Galaxies through Near-infrared Integrated Light Variability
摘要： Luminous and ultra-luminous infrared galaxies ((U)LIRGs) are rare today but are increasingly abundant at high redshifts. They are believed to be dusty starbursts, and hence should have high rates of supernovae (multiple events per year). Due to their extremely dusty environment, however, such supernovae could only be detected in rest-frame infrared and longer wavelengths, where our current facilities lack the capability of finding them individually beyond the local universe. We propose a new technique for higher redshifts, which is to search for the presence of supernovae through the variability of the integrated rest-frame infrared light of the entire hosts. We present a pilot study to assess the feasibility of this technique. We exploit a unique region, the "IRAC Dark Field" (IDF), that the Spitzer Space Telescope has observed for more than 14 years in 3–5 μm. The IDF also has deep far-infrared data (200–550 μm) from the Herschel Space Observatory that allow us to select high-redshift (U)LIRGs. We obtain a sample of (U)LIRGs that have secure optical counterparts, and examine their light curves in 3–5 μm. While the variabilities could also be caused by AGNs, we show that such contaminations can be identified. We present two cases where the distinct features in their light curves are consistent with multiple supernovae overlapping in time. Searching for supernovae this way will be relevant to the James Webb Space Telescope (JWST) to probe high-redshift (U)LIRGs into their nuclear regions where JWST will be limited by its resolution.
关键词： submillimeter: galaxies,galaxies: active,galaxies: starburst,extinction,supernovae: general,dust
更新于2025-09-23 15:21:01
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Massive and dusty Hα emitters in protocluster revealed by ALMA and JVLA
摘要： We investigate the physical properties of Hα emitters (HAEs) associated to the protocluster 4C23.56 at z ～ 2.5 using continuum observations at submm (270 GHz) and radio (3 GHz) frequencies with Atacama Large Mm/submm Array (ALMA) and K. Jansky Very Large Array (JVLA). For more details see Lee et al. (in prep).
关键词： radio continuum: galaxies,galaxies: high-redshift,galaxies: structure,submillimeter,galaxies: evolution
更新于2025-09-23 15:19:57