The Astropy Problem

The Astropy Project (http://astropy.org) is, in its own words, "a community effort to develop a single core package for Astronomy in Python and foster interoperability between Python astronomy packages." For five years this project has been managed, written, and operated as a grassroots, self-organized, almost entirely volunteer effort while the software is used by the majority of the astronomical community. Despite this, the project has always been and remains to this day effectively unfunded. Further, contributors receive little or no formal recognition for creating and supporting what is now critical software. This paper explores the problem in detail, outlines possible solutions to correct this, and presents a few suggestions on how to address the sustainability of general purpose astronomical software

The contribution by luminous blue variable stars to the dust content of the Magellanic Clouds

Context. Previous studies have concluded that low- and intermediate-mass stars cannot account for the interstellar dust yield in the Magellanic Clouds inferred from far-infrared and sub-millimetre observations.Aims. Luminous blue variable stars (LBVs) form dust as a result of episodic, violent mass loss. To investigate their contribution as dust producers in the Magellanic Clouds, we analyse 31 confirmed and candidate LBVs from a recent census.Methods. We built a maximally complete multi-wavelength dataset of these sources from archival space telescope images and catalogues from near-infrared to millimetre wavelengths. We also present new Very Large Telescope VISIR observations of three sources in the Large Magellanic Cloud (LMC). We review the LBV classification on the basis of the infrared spectral energy distribution. To derive characteristic dust parameters, we fitted the photometry resulting from a stacking analysis, which consists of co-adding images of the same wavelength band of several targets to improve the signal-to-noise. For comparison we also stacked the images of low- and intermediate-mass evolved stars in the LMC.Results. We find four classes of sources: (1) LBVs showing mid-infrared dust emission plus near-infrared free-free emission from an ionised stellar wind (Class 1a) or only mid-infrared dust emission (Class 1b); (2) LBVs with a near-infrared excess due to free-free emission only (Class 2); (3) objects with an sgB[e] classification in the literature, displaying a distinctive hot dust component; and (4) objects with no detected stellar winds and no circumstellar matter in their SEDs. From the stacking analysis of the 18 Class 1 and 2 objects in the LMC, we derived an integrated dust mass of 0.11−0.03+0.06 M⊙. This is two orders of magnitude larger than the value inferred from stacking 1342 extreme-asymptotic giant branch stars. The dust mass of individual LBVs does not correlate with the stellar parameters, possibly suggesting that the dust production mechanism is independent of the initial stellar mass or that the stars have different evolutionary histories. The total dust yield from LBVs over the age of the LMC is ∼104 − 105 M⊙. The one order of magnitude uncertainty is mainly due to uncertainties of the LBV population, star formation history, and initial mass function.Conclusions. LBVs are potentially the second most important source of dust in normal galaxies. The role of dust destruction in LBV nebulae by a possible subsequent supernova (SN) blast wave has yet to be determined. Recent theoretical developments in the field of dust processing by SN shocks highlight the potential survival of dust grains from the pre-existing circumstellar nebula.<br/

BAT AGN Spectroscopic Survey-XXIII. A New Mid-Infrared Diagnostic for Absorption in Active Galactic Nuclei

In this study, we use the SWIFT/BAT AGN sample, which has received extensive multiwavelength follow-up analysis as a result of the BAT AGN Spectroscopic Survey (BASS), to develop a diagnostic for nuclear obscuration by examining the relationship between the line-of-sight column densities ($N_{\rm{H}}$), the 2-10 keV-to-$12\,\rm{\mu m}$ luminosity ratio, and WISE mid-infrared colors. We demonstrate that heavily obscured AGNs tend to exhibit both preferentially ''redder'' mid-infrared colors and lower values of $L_{\rm{X,\,Obs.}}$/$L_{12\,\rm{\mu m}}$ than less obscured AGNs, and we derive expressions relating $N_{\rm{H}}$ to the $L_{\rm{X,\,Obs.}}$/$L_{12\,\rm{\mu m}}$ and $L_{22\,\rm{\mu m}}$/$L_{4.6\,\rm{\mu m}}$ luminosity ratios as well as develop diagnostic criteria using these ratios. Our diagnostic regions yield samples that are $\gtrsim80$% complete and $\gtrsim60$% pure for AGNs with log($N_{\rm{H}})\geq24$, as well as $\gtrsim85$% pure for AGNs with $\rm{log}(N_{\rm{H}})\gtrsim23.5$. We find that these diagnostics cannot be used to differentiate between optically star forming galaxies and active galaxies. Further, mid-IR contributions from host galaxies that dominate the observed $12~\rm{\mu m}$ emission can lead to larger apparent X-ray deficits and redder mid-IR colors than the AGNs would intrinsically exhibit, though this effect helps to better separate less obscured and more obscured AGNs. Finally, we test our diagnostics on two catalogs of AGNs and infrared galaxies, including the XMM-Newton XXL-N field, and we identify several known Compton-thick AGNs as well as a handful of candidate heavily obscured AGNs based upon our proposed obscuration diagnostics.Comment: 28 pages: 1-19 main text, 20-28 appendix and references. 15 figures. Accepted for publication in ApJS; part of BASS DR2 special issu

Development and validation of novel clinical endpoints in intermediate age-related macular degeneration in MACUSTAR

Background. Currently, no validated clinical endpoints for treatment studies exist for intermediate age-related macular degeneration (iAMD). Objective. The European MACUSTAR study aims to develop and clinically validate adequate clinical endpoints for future treatment studies in iAMD and to identify early determinants of disease progression to late stage AMD. Material and methods. The MACUSTAR study protocol was developed by an international consortium of researchers from academia, the pharmaceutical industry and medical device companies. The MACUSTAR project is funded by the Innovative Medicines Initiative 2 (IMI2) of the European Union. Results. The MACUSTAR study consists of a cross-sectional and a longitudinal investigation. A total of 750 subjects with early, intermediate and late AMD as well as control subjects with no signs of AMD will be included with a follow-up period of 3 years. Overall, 20 European study centers are involved. Conclusion. The MACUSTAR project will generate large high-quality datasets, which will allow clinical validation of novel endpoints for future interventional trials in iAMD. The aim is that these endpoints will be accepted as suitable for medication approval studies by the regulatory authorities and that understanding of the disease process will be improved