Zooniverse

Abstract:

We investigate the development of scientific content knowledge of volunteers participating in online citizen science projects in the Zooniverse (www.zooniverse.org). We use econometric methods to test how measures of project participation relate to success in a science quiz, controlling for factors known to correlate with scientific knowledge. Citizen scientists believe they are learning about both the content and processes of science through their participation. We don’t directly test the latter, but we find evidence to support the former - that more actively engaged participants perform better in a project-specific science knowledge quiz, even after controlling for their general science knowledge. We interpret this as evidence of learning of science content inspired by participation in online citizen science.

Abstract:

We discuss a potential MeerKAT campaign to shed more light into the nature of the optically identified Blue Early Type galaxies (BETGs), a subset of the so-called "green valley" population, quenching star formation on time scales of less than 0.25 Gyr and the likely progenitor population of post-starburst galaxies. Employing a WSRT pilot survey of four galaxies, we have shown that BETGs have radio properties that fit to a mechanical removal of star forming material, potentially by AGN activity, as in particular we found H I to be removed farther and farther from the centre of the galaxies with older and older age of the stellar population. We argue that MeerKAT is the optimal instrument to conduct a pointed survey of BETGs to become more conclusive about this specific transition state, which is so rare that it will not be detected at a high enough rate in planned sufficiently sensitive large-sky surveys, for which we expect a total detection number of the order of 12 objects.

Abstract:

We present deep Chandra X-ray observations of the core of IC 2497, the galaxy associated with Hanny's Voorwerp and hosting a fading AGN. We find extended soft X-ray emission from hot gas around the low intrinsic luminosity (unobscured) AGN ($L_{\rm bol} \sim 10^{42}-10^{44}$ erg s$^{-1}$). The temperature structure in the hot gas suggests the presence of a bubble or cavity around the fading AGN ($\mbox{E$_{\rm bub}$} \sim 10^{54} - 10^{55}$ erg). A possible scenario is that this bubble is inflated by the fading AGN, which after changing accretion state is now in a kinetic mode. Other possibilities are that the bubble has been inflated by the past luminous quasar ($L_{\rm bol} \sim 10^{46}$ erg s$^{-1}$), or that the temperature gradient is an indication of a shock front from a superwind driven by the AGN. We discuss the possible scenarios and the implications for the AGN-host galaxy interaction, as well as an analogy between AGN and X-ray binaries lifecycles. We conclude that the AGN could inject mechanical energy into the host galaxy at the end of its lifecycle, and thus provide a source for mechanical feedback, in a similar way as observed for X-ray binaries.