235 research outputs found

    Cross-correlating Carbon Monoxide Line-intensity Maps with Spectroscopic and Photometric Galaxy Surveys

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    Line-intensity mapping (LIM or IM) is an emerging field of observational work, with strong potential to fit into a larger effort to probe large-scale structure and small-scale astrophysical phenomena using multiple complementary tracers. Taking full advantage of such complementarity means, in part, undertaking line-intensity surveys with galaxy surveys in mind. We consider the potential for detection of a cross-correlation signal between COMAP and blind surveys based on photometric redshifts (as in COSMOS) or based on spectroscopic data (as with the HETDEX survey of Lyman-α\alpha emitters). We find that obtaining σz/(1+z)0.003\sigma_z/(1+z)\lesssim0.003 accuracy in redshifts and 104\gtrsim10^{-4} sources per Mpc3^3 with spectroscopic redshift determination should enable a CO-galaxy cross spectrum detection significance at least twice that of the CO auto spectrum. Either a future targeted spectroscopic survey or a blind survey like HETDEX may be able to meet both of these requirements.Comment: 19 pages + appendix (31 pages total), 16 figures, 6 tables; accepted for publication in Ap

    CCAT-prime: Science with an Ultra-widefield Submillimeter Observatory at Cerro Chajnantor

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    We present the detailed science case, and brief descriptions of the telescope design, site, and first light instrument plans for a new ultra-wide field submillimeter observatory, CCAT-prime, that we are constructing at a 5600 m elevation site on Cerro Chajnantor in northern Chile. Our science goals are to study star and galaxy formation from the epoch of reionization to the present, investigate the growth of structure in the Universe, improve the precision of B-mode CMB measurements, and investigate the interstellar medium and star formation in the Galaxy and nearby galaxies through spectroscopic, polarimetric, and broadband surveys at wavelengths from 200 um to 2 mm. These goals are realized with our two first light instruments, a large field-of-view (FoV) bolometer-based imager called Prime-Cam (that has both camera and an imaging spectrometer modules), and a multi-beam submillimeter heterodyne spectrometer, CHAI. CCAT-prime will have very high surface accuracy and very low system emissivity, so that combined with its wide FoV at the unsurpassed CCAT site our telescope/instrumentation combination is ideally suited to pursue this science. The CCAT-prime telescope is being designed and built by Vertex Antennentechnik GmbH. We expect to achieve first light in the spring of 2021.Comment: Presented at SPIE Millimeter, Submillimeter, and Far-Infrared Detectors and Instrumentation for Astronomy IX, June 14th, 201

    The A9 dopamine neuron component in grafts of ventral mesencephalon is an important determinant for recovery of motor function in a rat model of Parkinson’s disease

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    Grafts of foetal ventral mesencephalon, used in cell replacement therapy for Parkinson’s disease, are known to contain a mix of dopamine neuronal subtypes including the A9 neurons of the substantia nigra and the A10 neurons of the ventral tegmental area. However, the relative importance of these subtypes for functional repair of the brain affected by Parkinson’s disease has not been studied thoroughly. Here, we report results from a series of grafting experiments where the anatomical and functional properties of grafts either selectively lacking in A9 neurons, or with a typical A9/A10 composition were compared. The results show that the A9 component of intrastriatal grafts is of critical importance for recovery in tests on motor performance, in a rodent model of Parkinson’s disease. Analysis at the histological level indicates that this is likely to be due to the unique ability of A9 neurons to innervate and functionally activate their target structure, the dorsolateral region of the host striatum. The findings highlight dopamine neuronal subtype composition as a potentially important parameter to monitor in order to understand the variable nature of functional outcome better in transplantation studies. Furthermore, the results have interesting implications for current efforts in this field to generate well-characterized and standardized preparations of transplantable dopamine neuronal progenitors from stem cells

    Cardiopulmonary Impact of Particulate Air Pollution in High-Risk Populations: JACC State-of-the-Art Review

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    Fine particulate air pollution <2.5 μm in diameter (PM(2.5)) is a major environmental threat to global public health. Multiple national and international medical and governmental organizations have recognized PM(2.5) as a risk factor for cardiopulmonary diseases. A growing body of evidence indicates that several personal-level approaches that reduce exposures to PM(2.5) can lead to improvements in health endpoints. Novel and forward-thinking strategies including randomized clinical trials are important to validate key aspects (e.g., feasibility, efficacy, health benefits, risks, burden, costs) of the various protective interventions, in particular among real-world susceptible and vulnerable populations. This paper summarizes the discussions and conclusions from an expert workshop, Reducing the Cardiopulmonary Impact of Particulate Matter Air Pollution in High Risk Populations, held on May 29 to 30, 2019, and convened by the National Institutes of Health, the U.S. Environmental Protection Agency, and the U.S. Centers for Disease Control and Prevention

    COMAP Early Science: VIII. A Joint Stacking Analysis with eBOSS Quasars

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    We present a new upper limit on the cosmic molecular gas density at z = 2.4 − 3.4 obtained using the first year of observations from the CO Mapping Array Project (COMAP). COMAP data cubes are stacked on the 3D positions of 243 quasars selected from the Extended Baryon Oscillation SpectroscopicSurvey (eBOSS) catalog, yielding a 95% upper limit for flux from CO(1-0) line emission of 0.129 Jykm/s. Depending on the balance of the emission between the quasar host and its environment, this value can be interpreted as an average CO line luminosity L′CO of eBOSS quasars of ≤ 1.26 × 1011 K km pc2s−1, or an average molecular gas density ρH2 in regions of the universe containing a quasar of ≤ 1.52 × 108 M⊙ cMpc−3. The L′ CO upper limit falls among CO line luminosities obtained fromindividually-targeted quasars in the COMAP redshift range, and the ρH2 value is comparable to upper limits obtained from other Line Intensity Mapping (LIM) surveys and their joint analyses. Further, we forecast the values obtainable with the COMAP/eBOSS stack after the full 5-year COMAP Pathfinder survey. We predict that a detection is probable with this method, depending on the CO properties of the quasar sample. Based on the achieved sensitivity, we believe that this technique of stacking LIM data on the positions of traditional galaxy or quasar catalogs is extremely promising, both asa technique for investigating large galaxy catalogs efficiently at high redshift and as a technique for bolstering the sensitivity of LIM experiments, even with a fraction of their total expected survey data

    COMAP Early Science: VIII. A Joint Stacking Analysis with eBOSS Quasars

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    We present a new upper limit on the cosmic molecular gas density at z=2.43.4z=2.4-3.4 obtained using the first year of observations from the CO Mapping Array Project (COMAP). COMAP data cubes are stacked on the 3D positions of 282 quasars selected from the Extended Baryon Oscillation Spectroscopic Survey (eBOSS) catalog, yielding a 95% upper limit for flux from CO(1-0) line emission of 0.210 Jy km/s. Depending on the assumptions made, this value can be interpreted as either an average CO line luminosity LCOL'_\mathrm{CO} of eBOSS quasars of 7.30×1010\leq 7.30\times10^{10} K km pc2^2 s1^{-1}, or an average molecular gas density ρH2\rho_\mathrm{H_2} in regions of the universe containing a quasar of 2.02×108\leq 2.02\times10^8 M_\odot cMpc3^{-3}. The LCOL'_\mathrm{CO} upper limit falls among CO line luminosities obtained from individually-targeted quasars in the COMAP redshift range, and the ρH2\rho_\mathrm{H_2} value is comparable to upper limits obtained from other Line Intensity Mapping (LIM) surveys and their joint analyses. Further, we forecast the values obtainable with the COMAP/eBOSS stack after the full 5-year COMAP Pathfinder survey. We predict that a detection is probable with this method, depending on the CO properties of the quasar sample. Based on these achieved sensitivities, we believe that this technique of stacking LIM data on the positions of traditional galaxy or quasar catalogs is extremely promising, both as a technique for investigating large galaxy catalogs efficiently at high redshift and as a technique for bolstering the sensitivity of LIM experiments, even with a fraction of their total expected survey data.Comment: 15 pages, 8 figures. To be submitted to Ap

    COMAP Early Science: III. CO Data Processing

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    We describe the first season COMAP analysis pipeline that converts raw detector readouts to calibrated sky maps. This pipeline implements four main steps: gain calibration, filtering, data selection, and map-making. Absolute gain calibration relies on a combination of instrumental and astrophysical sources, while relative gain calibration exploits real-time total-power variations. High efficiency filtering is achieved through spectroscopic common-mode rejection within and across receivers, resulting in nearly uncorrelated white noise within single-frequency channels. Consequently, near-optimal but biased maps are produced by binning the filtered time stream into pixelized maps; the corresponding signal bias transfer function is estimated through simulations. Data selection is performed automatically through a series of goodness-of-fit statistics, including χ2\chi^2 and multi-scale correlation tests. Applying this pipeline to the first-season COMAP data, we produce a dataset with very low levels of correlated noise. We find that one of our two scanning strategies (the Lissajous type) is sensitive to residual instrumental systematics. As a result, we no longer use this type of scan and exclude data taken this way from our Season 1 power spectrum estimates. We perform a careful analysis of our data processing and observing efficiencies and take account of planned improvements to estimate our future performance. Power spectrum results derived from the first-season COMAP maps are presented and discussed in companion papers.Comment: Paper 3 of 7 in series. 26 pages, 23 figures, submitted to Ap
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