25 research outputs found
Amalgame: Cosmological Constraints from the First Combined Photometric Supernova Sample
Future constraints of cosmological parameters from Type Ia supernovae (SNe
Ia) will depend on the use of photometric samples, those samples without
spectroscopic measurements of the SNe Ia. There is a growing number of analyses
that show that photometric samples can be utilised for precision cosmological
studies with minimal systematic uncertainties. To investigate this claim, we
perform the first analysis that combines two separate photometric samples, SDSS
and Pan-STARRS, without including a low-redshift anchor. We evaluate the
consistency of the cosmological parameters from these two samples and find they
are consistent with each other to under . From the combined sample,
named Amalgame, we measure with SN alone in a flat
CDM model, and and when combining with a Planck data prior and a flat
CDM model. These results are consistent with constraints from the Pantheon+
analysis of only spectroscopically confirmed SNe Ia, and show that there are no
significant impediments to analyses of purely photometric samples of SNe Ia.Comment: Submitting to MNRAS; comments welcom
Advanced Technology Large-Aperture Space Telescope (ATLAST): A Technology Roadmap for the Next Decade
The Advanced Technology Large-Aperture Space Telescope (ATLAST) is a set of
mission concepts for the next generation of UVOIR space observatory with a
primary aperture diameter in the 8-m to 16-m range that will allow us to
perform some of the most challenging observations to answer some of our most
compelling questions, including "Is there life elsewhere in the Galaxy?" We
have identified two different telescope architectures, but with similar optical
designs, that span the range in viable technologies. The architectures are a
telescope with a monolithic primary mirror and two variations of a telescope
with a large segmented primary mirror. This approach provides us with several
pathways to realizing the mission, which will be narrowed to one as our
technology development progresses. The concepts invoke heritage from HST and
JWST design, but also take significant departures from these designs to
minimize complexity, mass, or both.
Our report provides details on the mission concepts, shows the extraordinary
scientific progress they would enable, and describes the most important
technology development items. These are the mirrors, the detectors, and the
high-contrast imaging technologies, whether internal to the observatory, or
using an external occulter. Experience with JWST has shown that determined
competitors, motivated by the development contracts and flight opportunities of
the new observatory, are capable of achieving huge advances in technical and
operational performance while keeping construction costs on the same scale as
prior great observatories.Comment: 22 pages, RFI submitted to Astro2010 Decadal Committe
Recommended from our members
Effect of Hydrocortisone on Mortality and Organ Support in Patients With Severe COVID-19: The REMAP-CAP COVID-19 Corticosteroid Domain Randomized Clinical Trial.
Importance: Evidence regarding corticosteroid use for severe coronavirus disease 2019 (COVID-19) is limited. Objective: To determine whether hydrocortisone improves outcome for patients with severe COVID-19. Design, Setting, and Participants: An ongoing adaptive platform trial testing multiple interventions within multiple therapeutic domains, for example, antiviral agents, corticosteroids, or immunoglobulin. Between March 9 and June 17, 2020, 614 adult patients with suspected or confirmed COVID-19 were enrolled and randomized within at least 1 domain following admission to an intensive care unit (ICU) for respiratory or cardiovascular organ support at 121 sites in 8 countries. Of these, 403 were randomized to open-label interventions within the corticosteroid domain. The domain was halted after results from another trial were released. Follow-up ended August 12, 2020. Interventions: The corticosteroid domain randomized participants to a fixed 7-day course of intravenous hydrocortisone (50 mg or 100 mg every 6 hours) (n = 143), a shock-dependent course (50 mg every 6 hours when shock was clinically evident) (n = 152), or no hydrocortisone (n = 108). Main Outcomes and Measures: The primary end point was organ support-free days (days alive and free of ICU-based respiratory or cardiovascular support) within 21 days, where patients who died were assigned -1 day. The primary analysis was a bayesian cumulative logistic model that included all patients enrolled with severe COVID-19, adjusting for age, sex, site, region, time, assignment to interventions within other domains, and domain and intervention eligibility. Superiority was defined as the posterior probability of an odds ratio greater than 1 (threshold for trial conclusion of superiority >99%). Results: After excluding 19 participants who withdrew consent, there were 384 patients (mean age, 60 years; 29% female) randomized to the fixed-dose (n = 137), shock-dependent (n = 146), and no (n = 101) hydrocortisone groups; 379 (99%) completed the study and were included in the analysis. The mean age for the 3 groups ranged between 59.5 and 60.4 years; most patients were male (range, 70.6%-71.5%); mean body mass index ranged between 29.7 and 30.9; and patients receiving mechanical ventilation ranged between 50.0% and 63.5%. For the fixed-dose, shock-dependent, and no hydrocortisone groups, respectively, the median organ support-free days were 0 (IQR, -1 to 15), 0 (IQR, -1 to 13), and 0 (-1 to 11) days (composed of 30%, 26%, and 33% mortality rates and 11.5, 9.5, and 6 median organ support-free days among survivors). The median adjusted odds ratio and bayesian probability of superiority were 1.43 (95% credible interval, 0.91-2.27) and 93% for fixed-dose hydrocortisone, respectively, and were 1.22 (95% credible interval, 0.76-1.94) and 80% for shock-dependent hydrocortisone compared with no hydrocortisone. Serious adverse events were reported in 4 (3%), 5 (3%), and 1 (1%) patients in the fixed-dose, shock-dependent, and no hydrocortisone groups, respectively. Conclusions and Relevance: Among patients with severe COVID-19, treatment with a 7-day fixed-dose course of hydrocortisone or shock-dependent dosing of hydrocortisone, compared with no hydrocortisone, resulted in 93% and 80% probabilities of superiority with regard to the odds of improvement in organ support-free days within 21 days. However, the trial was stopped early and no treatment strategy met prespecified criteria for statistical superiority, precluding definitive conclusions. Trial Registration: ClinicalTrials.gov Identifier: NCT02735707
Amalgame: Cosmological Constraints from the First Combined Photometric Supernova Sample
International audienceFuture constraints of cosmological parameters from Type Ia supernovae (SNe Ia) will depend on the use of photometric samples, those samples without spectroscopic measurements of the SNe Ia. There is a growing number of analyses that show that photometric samples can be utilised for precision cosmological studies with minimal systematic uncertainties. To investigate this claim, we perform the first analysis that combines two separate photometric samples, SDSS and Pan-STARRS, without including a low-redshift anchor. We evaluate the consistency of the cosmological parameters from these two samples and find they are consistent with each other to under . From the combined sample, named Amalgame, we measure with SN alone in a flat CDM model, and and when combining with a Planck data prior and a flat CDM model. These results are consistent with constraints from the Pantheon+ analysis of only spectroscopically confirmed SNe Ia, and show that there are no significant impediments to analyses of purely photometric samples of SNe Ia
Amalgame: cosmological constraints from the first combined photometric supernova sample
Future constraints of cosmological parameters from Type Ia supernovae (SNe Ia) will depend on the use of photometric samples, those samples without spectroscopic measurements of the SNe Ia. There is a growing number of analyses that show that photometric samples can be utilised for precision cosmological studies with minimal systematic uncertainties. To investigate this claim, we perform the first analysis that combines two separate photometric samples, SDSS and Pan-STARRS, without including a low-redshift anchor. We evaluate the consistency of the cosmological parameters from these two samples and find they are consistent with each other to under 1σ. From the combined sample, named Amalgame, we measure ΩM=0.328±0.024 with SN alone in a flat ΛCDM model, and ΩM=0.330±0.018 and w=−1.016+0.055−0.058 when combining with a Planck data prior and a flat wCDM model. These results are consistent with constraints from the Pantheon+ analysis of only spectroscopically confirmed SNe Ia, and show that there are no significant impediments to analyses of purely photometric samples of SNe Ia
The Pantheon+ Analysis: Cosmological Constraints
We present constraints on cosmological parameters from the Pantheon+ analysis of 1701 light curves of 1550 distinct Type Ia supernovae (SNe Ia) ranging in redshift from to 2.26. This work features an increased sample size, increased redshift span, and improved treatment of systematic uncertainties in comparison to the original Pantheon analysis and results in a factor of two improvement in cosmological constraining power. For a FlatCDM model, we find from SNe Ia alone. For a FlatCDM model, we measure from SNe Ia alone, H km s Mpc when including the Cepheid host distances and covariance (SH0ES), and when combining the SN likelihood with constraints from the cosmic microwave background (CMB) and baryon acoustic oscillations (BAO); both values are consistent with a cosmological constant. We also present the most precise measurements to date on the evolution of dark energy in a FlatCDM universe, and measure from Pantheon+ alone, H km s Mpc when including SH0ES, and when combining Pantheon+ with CMB and BAO data. Finally, we find that systematic uncertainties in the use of SNe Ia along the distance ladder comprise less than one third of the total uncertainty in the measurement of H and cannot explain the present "Hubble tension" between local measurements and early-Universe predictions from the cosmological model
Studies on Improving the Immobilized Bead Reusability and Alkaline Protease Production by Isolated Immobilized Bacillus circulans (MTCC 6811) Using Overall Evaluation Criteria
The Pantheon+ Analysis: Cosmological Constraints
We present constraints on cosmological parameters from the Pantheon+ analysis of 1701 light curves of 1550 distinct Type Ia supernovae (SNe Ia) ranging in redshift from to 2.26. This work features an increased sample size, increased redshift span, and improved treatment of systematic uncertainties in comparison to the original Pantheon analysis and results in a factor of two improvement in cosmological constraining power. For a FlatCDM model, we find from SNe Ia alone. For a FlatCDM model, we measure from SNe Ia alone, H km s Mpc when including the Cepheid host distances and covariance (SH0ES), and when combining the SN likelihood with constraints from the cosmic microwave background (CMB) and baryon acoustic oscillations (BAO); both values are consistent with a cosmological constant. We also present the most precise measurements to date on the evolution of dark energy in a FlatCDM universe, and measure from Pantheon+ alone, H km s Mpc when including SH0ES, and when combining Pantheon+ with CMB and BAO data. Finally, we find that systematic uncertainties in the use of SNe Ia along the distance ladder comprise less than one third of the total uncertainty in the measurement of H and cannot explain the present "Hubble tension" between local measurements and early-Universe predictions from the cosmological model