Galaxy Nurseries: Crowdsourced analysis of slitless spectroscopic data

We present the results of Galaxy Nurseries project, which was designed to enable crowdsourced analysis of slitless spectroscopic data by volunteer citizen scientists using the Zooniverse online interface. The dataset was obtained by the WFC3 Infrared Spectroscopic Parallel (WISP) Survey collaboration and comprises NIR grism (G102 and G141) and direct imaging. Volunteers were instructed to evaluate indicated spectral features and decide whether it was a genuine emission line or more likely an artifact. Galaxy Nurseries was completed in only 40 days, gathering 414,360 classifications from 3003 volunteers for 27,333 putative emission lines. The results of Galaxy Nurseries demonstrate the feasibility of identifying genuine emission lines in slitless spectra by citizen scientists. Volunteer responses for each subject were aggregated to compute $f_{\mathrm{Real}}$, the fraction of volunteers who classified the corresponding emission line as "Real". To evaluate the accuracy of volunteer classifications, their aggregated responses were compared with independent assessments provided by members of the WISP Survey Science Team (WSST). Overall, there is a broad agreement between the WSST and volunteers' classifications, although we recognize that robust scientific analyses typically require samples with higher purity and completeness than raw volunteer classifications provide. Nonetheless, choosing optimal threshold values for $f_{\mathrm{Real}}$ allows a large fraction of spurious lines to be vetoed, substantially reducing the timescale for subsequent professional analysis of the remaining potential lines.Comment: Accepted for publication in Research Notes of the AA

Least squares methods of analyzing spectroscopic data

An overview of the methods of line-by-line and whole-band analysis developed by The Ohio State University spectroscopy group is presented

The Status of Spectroscopic Data for the Exoplanet Characterisation Missions

The status of laboratory spectroscopic data for exoplanet characterisation missions such as EChO is reviewed. For many molecules (eg H2O, CO, CO2, H3+, O2, O3) the data are already available. For the other species work is actively in progress constructing this data. Much of the is work is being undertaken by ExoMol project (www.exomol.com). This information will be used to construct and EChO-specific spectroscopic database.Comment: Experimental Astronomy, accepte

Reddenings of FGK supergiants and classical Cepheids from spectroscopic data

Accurate and homogeneous atmospheric parameters (Teff, log (g), Vt, [Fe/H]) are derived for 74 FGK non-variable supergiants from high-resolution, high signal-to-noise ratio, echelle spectra. Extremely high precision for the inferred effective temperatures (10-40 K) is achieved by using the line-depth ratio method. The new data are combined with atmospheric values for 164 classical Cepheids, observed at 675 different pulsation phases, taken from our previously published studies. The derived values are correlated with unreddened B-V colours compiled from the literature for the investigated stars in order to obtain an empirical relationship of the form: (B-V)o = 57.984 - 10.3587(log Teff)^2 + 1.67572(log Teff)^3 - 3.356(log (g)) + 0.0321(Vt) + 0.2615[Fe/H] + 0.8833((log (g))(log Teff)). The expression is used to estimate colour excesses E(B-V) for individual supergiants and classical Cepheids, with a precision of +-0.05 mag. for supergiants and Cepheids with n=1-2 spectra, reaching +-0.025 mag. for Cepheids with n>2 spectra, matching uncertainties for the most sophisticated photometric techniques. The reddening scale is also a close match to the system of space reddenings for Cepheids. The application range is for spectral types F0--K0 and luminosity classes I and II.Comment: accepted for publication (MNRAS

Laboratory spectroscopy in support of atmospheric measurements

Optical measurements of trace species in the atmosphere require precise, accurate spectroscopic data for the molecules under study. This laboratory exits to provide high quality spectroscopic data for the interpretation of data from existing satellite, balloon, ground, and aircraft instruments, as well as to provide sufficient data to assess the feasibility of new instruments

Approximate Emissivity Calculations for Polyatomic Molecules. I. CO_2

Approximate emissivity calculations for CO_2 have been carried out, as a function of optical density, at 300 and at 600°K. The calculations involve the assumption that the rotational lines overlap extensively. This condition appears to be satisfied at total pressures above about 1 atmos. Comparison of the values calculated from spectroscopic data with the emissivities tabulated by Hottel and his collaborators shows satisfactory agreement. The analysis presented in this manuscript emphasizes the fact that it is possible to obtain reasonable estimates for the engineering emissivity without performing extensive analytical work, provided the physical principles are understood and the needed spectroscopic data are available

Making the H-Cluster from Scratch

Spectroscopic data begin to elucidate the initial steps in the biosynthesis of the hydrogenase active site. [Also see Report by Kuchenreuther et al. ] </jats:p

Multiple populations in Omega Centauri: a cluster analysis of spectroscopic data

Omega Cen is composed of several stellar populations. Their history might allow us to reconstruct the evolution of this complex object. We performed a statistical cluster analysis on the large data set provided by Johnson and Pilachowski (2010). Stars in Omega Cen divide into three main groups. The metal-poor group includes about a third of the total. It shows a moderate O-Na anticorrelation, and similarly to other clusters, the O-poor second generation stars are more centrally concentrated than the O-rich first generation ones. This whole population is La-poor, with a pattern of abundances for n-capture elements which is very close to a scaled r-process one. The metal-intermediate group includes the majority of the cluster stars. This is a much more complex population, with an internal spread in the abundances of most elements. It shows an extreme O-Na anticorrelation, with a very numerous population of extremely O-poor and He-rich second generation stars. This second generation is very centrally concentrated. This whole population is La-rich, with a pattern of the abundances of n-capture elements that shows a strong contribution by the s-process. The spread in metallicity within this metal-intermediate population is not very large, and we might attribute it either to non uniformities of an originally very extended star forming region, or to some ability to retain a fraction of the ejecta of the core collapse SNe that exploded first, or both. As previously noticed, the metal-rich group has an Na-O correlation, rather than anticorrelation. There is evidence for the contribution of both massive stars ending their life as core-collapse SNe, and intermediate/low mass stars, producing the s-capture elements. Kinematics of this population suggests that it formed within the cluster rather than being accreted.Comment: Accepted for publication in Astronomy and Astrophysic