Hidden in plain sight: a massive, dusty starburst in a galaxy protocluster at z=5.7 in the COSMOS field

We report the serendipitous discovery of a dusty, starbursting galaxy at $z=5.667$ (hereafter called CRLE) in close physical association with the "normal" main-sequence galaxy HZ10 at $z=5.654$. CRLE was identified by detection of [CII], [NII] and CO(2-1) line emission, making it the highest redshift, most luminous starburst in the COSMOS field. This massive, dusty galaxy appears to be forming stars at a rate of at least 1500$\,M_\odot$ yr$^{-1}$ in a compact region only $\sim3$ kpc in diameter. The dynamical and dust emission properties of CRLE suggest an ongoing merger driving the starburst, in a potentially intermediate stage relative to other known dusty galaxies at the same epoch. The ratio of [CII] to [NII] may suggest that an important ($\sim15\%$) contribution to the [CII] emission comes from a diffuse ionized gas component, which could be more extended than the dense, starbursting gas. CRLE appears to be located in a significant galaxy overdensity at the same redshift, potentially associated with a large-scale cosmic structure recently identified in a Lyman Alpha Emitter survey. This overdensity suggests that CRLE and HZ10 reside in a protocluster environment, offering the tantalizing opportunity to study the effect of a massive starburst on protocluster star formation. Our findings support the interpretation that a significant fraction of the earliest galaxy formation may occur from the inside out, within the central regions of the most massive halos, while rapidly evolving into the massive galaxy clusters observed in the local Universe.Comment: 16 pages, 9 figures, 4 tables, final version to appear on ApJ (accepted May 19, 2018

ALMA Reveals Weak [N II] Emission in "Typical" Galaxies and Intense Starbursts at z = 5–6

We report interferometric measurements of [N II] 205 μm fine-structure line emission from a representative sample of three galaxies at z = 5–6 using the Atacama Large (sub)Millimeter Array (ALMA). These galaxies were previously detected in [C II] and far-infrared continuum emission and span almost two orders of magnitude in star formation rate (SFR). Our results show at least two different regimes of ionized interstellar medium properties for galaxies in the first billion years of cosmic time, separated by their L_([C II])/L_([N II]) ratio. We find extremely low [N II] emission compared to [C II] (L_([C II])/L_([N II]) = 68^(+200)_(-28)) from a "typical" ~L_*(UV) star-forming galaxy, likely directly or indirectly (by its effect on the radiation field) related to low dust abundance and low metallicity. The infrared-luminous modestly star-forming Lyman-break galaxy (LBG) in our sample is characterized by an ionized-gas fraction (L_([C II])/L_([N II]) ≾ 20) typical of local star-forming galaxies and shows evidence for spatial variations in its ionized-gas fraction across an extended gas reservoir. The extreme SFR, warm and compact dusty starburst AzTEC-3 shows an ionized fraction higher than expected given its SFR surface density (L_([C II])/L_([N II]) = 22 ± 8) suggesting that [N II] dominantly traces a diffuse ionized medium rather than star-forming H II regions in this type of galaxy. This highest redshift sample of [N II] detections provides some of the first constraints on ionized and neutral gas modeling attempts and on the structure of the interstellar medium at z = 5–6 in "normal" galaxies and starbursts

Continental-scale patterns of extracellular enzyme activity in the subsoil: an overlooked reservoir of microbial activity

Chemical stabilization of microbial-derived products such as extracellular enzymes (EE) onto mineral surfaces has gained attention as a possibly important mechanism leading to the persistence of soil organic carbon (SOC). While the controls on EE activities and their stabilization in the surface soil are reasonably well-understood, how these activities change with soil depth and possibly diverge from those at the soil surface due to distinct physical, chemical, and biotic conditions remains unclear. We assessed EE activity to a depth of 1 m (10 cm increments) in 19 soil profiles across the Critical Zone Observatory Network, which represents a wide range of climates, soil orders, and vegetation types. For all EEs, activities per mass of soil correlated positively with microbial biomass (MB) and SOC, and all three of these variables decreased logarithmically with depth (p &lt; 0.05). Across all sites, over half of the potential EE activities per mass soil consistently occurred below 20 cm for all measured EEs. Activities per unit MB or SOC were substantially higher at depth (soils below 20 cm accounted for 80% of whole-profile EE activity), suggesting an accumulation of stabilized (i.e. mineral sorbed) EEs in subsoil horizons. The pronounced enzyme stabilization in subsurface horizons was corroborated by mixed-effects models that showed a significant, positive relationship between clay concentration and MB-normalized EE activities in the subsoil. Furthermore, the negative relationships between soil C, N, and P and C-, N-, and P-acquiring EEs found in the surface soil decoupled below 20 cm, which could have also been caused by EE stabilization. This finding suggests that EEs may not reflect soil nutrient availabilities deeper in the soil profile. Taken together, our results suggest that deeper soil horizons hold a significant reservoir of EEs, and that the controls of subsoil EEs differ from their surface soil counterparts. </div

Hidden in Plain Sight: A Massive, Dusty Starburst in a Galaxy Protocluster at z = 5.7 in the COSMOS Field

We report the serendipitous discovery of a dusty, starbursting galaxy at z = 5.667 (hereafter called CRLE) in close physical association with the "normal" main-sequence galaxy HZ10 at z = 5.654. CRLE was identified by detection of [C II], [N II], and CO(2–1) line emission, making it the highest-redshift, most luminous starburst in the COSMOS field. This massive, dusty galaxy appears to be forming stars at a rate of at least 1500 M⊙ yr^(−1) in a compact region only ~3 kpc in diameter. The dynamical and dust emission properties of CRLE suggest an ongoing merger driving the starburst, which is in a potentially intermediate stage relative to other known dusty galaxies at the same epoch. The ratio of [C II] to [N II] may suggest that an important (~15%) contribution to the [C II] emission comes from a diffuse ionized gas component, which could be more extended than the dense, starbursting gas. CRLE appears to be located in a significant galaxy overdensity at the same redshift, potentially associated with a large-scale cosmic structure recently identified in a Lyman α-emitter survey. This overdensity suggests that CRLE and HZ10 reside in a protocluster environment, offering the tantalizing opportunity to study the effect of a massive starburst on protocluster star formation. Our findings support the interpretation that a significant fraction of the earliest galaxy formation may occur from the inside out, within the central regions of the most massive halos, while rapidly evolving into the massive galaxy clusters observed in the local universe

CO Luminosity Density at High-z (COLDz) Survey: A Sensitive, Large-area Blind Search for Low-J CO Emission from Cold Gas in the Early Universe with the Karl G. Jansky Very Large Array

We describe the CO Luminosity Density at High-z (COLDz) survey, the first spectral line deep field targeting CO(1–0) emission from galaxies at z = 1.95–2.85 and CO(2–1) at z = 4.91–6.70. The main goal of COLDz is to constrain the cosmic density of molecular gas at the peak epoch of cosmic star formation. By targeting both a wide (~51 arcmin2) and a deep (~9 arcmin^2) area, the survey is designed to robustly constrain the bright end and the characteristic luminosity of the CO(1–0) luminosity function. An extensive analysis of the reliability of our line candidates and new techniques provide detailed completeness and statistical corrections as necessary to determine the best constraints to date on the CO luminosity function. Our blind search for CO(1–0) uniformly selects starbursts and massive main-sequence galaxies based on their cold molecular gas masses. Our search also detects CO(2–1) line emission from optically dark, dusty star-forming galaxies at z > 5. We find a range of spatial sizes for the CO-traced gas reservoirs up to ~40 kpc, suggesting that spatially extended cold molecular gas reservoirs may be common in massive, gas-rich galaxies at z ~ 2. Through CO line stacking, we constrain the gas mass fraction in previously known typical star-forming galaxies at z = 2–3. The stacked CO detection suggests lower molecular gas mass fractions than expected for massive main-sequence galaxies by a factor of ~3–6. We find total CO line brightness at ~34 GHz of 0.45 ± 0.2 μK, which constrains future line intensity mapping and CMB experiments

Genomic Profiling of Childhood Tumor Patient-Derived Xenograft Models to Enable Rational Clinical Trial Design.

Accelerating cures for children with cancer remains an immediate challenge as a result of extensive oncogenic heterogeneity between and within histologies, distinct molecular mechanisms evolving between diagnosis and relapsed disease, and limited therapeutic options. To systematically prioritize and rationally test novel agents in preclinical murine models, researchers within the Pediatric Preclinical Testing Consortium are continuously developing patient-derived xenografts (PDXs)-many of which are refractory to current standard-of-care treatments-from high-risk childhood cancers. Here, we genomically characterize 261 PDX models from 37 unique pediatric cancers; demonstrate faithful recapitulation of histologies and subtypes; and refine our understanding of relapsed disease. In addition, we use expression signatures to classify tumors for TP53 and NF1 pathway inactivation. We anticipate that these data will serve as a resource for pediatric oncology drug development and will guide rational clinical trial design for children with cancer

Association of Preoperative Risk Factors With Malignancy in Pancreatic Mucinous Cystic Neoplasms: A Multicenter Study

Pancreatic mucinous cystic neoplasms (MCNs) harbor malignant potential, and current guidelines recommend resection. However, data are limited on preoperative risk factors for malignancy (adenocarcinoma or high-grade dysplasia) occurring in the setting of an MCN