Heavily reddened type 1 quasars at z > 2 I: Evidence for significant obscured black-hole growth at the highest quasar luminosities

We present a new population of z>2 dust-reddened, Type 1 quasars with 0.5<E(B-V)<1.5, selected using near infra-red (NIR) imaging data from the UKIDSS-LAS, ESO-VHS and WISE surveys. NIR spectra obtained using the Very Large Telescope (VLT) for 24 new objects bring our total sample of spectroscopically confirmed hyperluminous (>10^{13}L_0), high-redshift dusty quasars to 38. There is no evidence for reddened quasars having significantly different H$\alpha$ equivalent widths relative to unobscured quasars. The average black-hole masses (~10^9-10^10 M_0) and bolometric luminosities (~10^{47} erg/s) are comparable to the most luminous unobscured quasars at the same redshift, but with a tail extending to very high luminosities of ~10^{48} erg/s. Sixty-six per cent of the reddened quasars are detected at $>3\sigma$ at 22um by WISE. The average 6um rest-frame luminosity is log10(L6um/erg/s)=47.1+/-0.4, making the objects among the mid-infrared brightest AGN currently known. The extinction-corrected space-density estimate now extends over three magnitudes (-30 < M_i < -27) and demonstrates that the reddened quasar luminosity function is significantly flatter than that of the unobscured quasar population at z=2-3. At the brightest magnitudes, M_i < -29, the space density of our dust-reddened population exceeds that of unobscured quasars. A model where the probability that a quasar becomes dust-reddened increases at high luminosity is consistent with the observations and such a dependence could be explained by an increase in luminosity and extinction during AGN-fuelling phases. The properties of our obscured Type 1 quasars are distinct from the heavily obscured, Compton-thick AGN that have been identified at much fainter luminosities and we conclude that they likely correspond to a brief evolutionary phase in massive galaxy formation.Comment: 16 pages, 9 figures (+ 2 appendices), Accepted for publication in MNRA

ICT Access and Use in Local Governance in Babati Town Council, Tanzania

This research examined access and use of ICT resources and services in Babati Town Council, Manyara Region, Tanzania. The research addressed a number of key issues relating to access and use of ICT by the local government workers and officials. Among the major issues that were addressed in this study included, how ICT is used to meet the information needs of the local government workers and officials. The extent to which ICT has made positive impacts on the way the local government workers and officials seek and use information. The study assessed the ICT infrastructure in the Babati Town Council, human capacity and political will and levels of funding to implement ICT-related programmes. The overall research design integrated both qualitative and quantitative designs. Data for the study was collected through questionnaires, face-to-face and informant interviews, official records and feedback workshops. The findings of this study revealed that there is poor access and connectivity to access ICT services and resources in the council, especially at work places. Furthermore, the results revealed that local government officials and workers are neither adequately knowledgeable nor skilled in ICT use. The study makes the following recommendations: First, the internet connectivity at the Town Council offices be improved to increase accessibility, and use of the internet services by local governmental officials and workers. Second, training of local government officials and workers on the use of ICT facilities be planned and implemented so as to increase knowledge and skills on access and use of ICT services. Third, budgetary allocation for ICT related projects and programmes in the council for connectivity, training, equipment be increased. Finally, in order to improve accessibility of ICT services in the council, sources of power should be improved and a library should be built

Internet Access and Use in Political Discourse by the Members of Parliament in Tanzania

This paper is based on the research which examined access and use of internet resources and services by the Tanzanian Members of Parliament (MPs) and its impact on the political discourse. The study was conducted in June 2009 among selected parliamentarians. It employed qualitative and quantitative research design. The sample size was 18 parliamentarians and these were selected purposively. The methods of data collection included a questionnaire, interviews and focus group discussion. Analysis of data was mainly descriptive. The key findings of this study are: First, the Parliament Library in Tanzania has made modest investment in ICT infrastructure to support internet access and use. Second, the Library has a good mix of professional and para- professional staff though the level of staffing is not optimum. Third, the Library has a number of important documents and publications available online including the Hansards and reports by various parliamentary committees. Fourth, the MPs have diverse needs although a few of these are central to all the MPs and these include information for debates, information on bills, policies, speeches and constituencies. The demand and need to access the internet resources and services by parliamentarians is on the rise and the parliament, including the parliament library, has to address a number of challenges in connection to this development. The reported challenges include: slow internet connectivity that discourages use; inadequate number of available PCs in the library (only 12 were available); lack of training programme to use the internet and e-resources in general; lack of effective marketing strategies to create awareness of the value of internet resources; low skills and capacities to use the internet resources among the MPs and the library staff; severe time constraint for the MPs to use the library regularly and finally, inadequate library physical space. Detailed suggestions made by the MPs on how these challenges could be addressed are also documented. Generally, the study observes a positive relationship between the use of the internet and increased/improved political discourse and the democratization process. However, one negative impact of the adoption of this new technology by the MPs is an increased knowledge and information gap between those with higher levels of education and the ones with lower levels of education. MPs with higher levels of education are the core group of internet users, while those with lower levels of education are the laggards. The knowledge and information gap is explained by the fact that the MPs with higher levels of education are likely to be better and more informed of significant issues of interest before the adoption of the internet. Thus, the use of the internet will increase and exacerbate this gap even further, unless strategies for intervention (such as training) are implemented. The paper makes a number of recommendations to address these emerging challenges and measures to mitigate negative impacts

Correcting CIV-Based Virial Black Hole Masses

The CIV broad emission line is visible in optical spectra to redshifts exceeding z~5. CIV has long been known to exhibit significant displacements to the blue and these `blueshifts' almost certainly signal the presence of strong outflows. As a consequence, single-epoch virial black hole (BH) mass estimates derived from CIV velocity-widths are known to be systematically biased compared to masses from the hydrogen Balmer lines. Using a large sample of 230 high-luminosity (log $L_{\rm Bol}$ = 45.5-48 erg/s), redshift 1.5<z<4.0 quasars with both CIV and Balmer line spectra, we have quantified the bias in CIV BH masses as a function of the CIV blueshift. CIV BH masses are shown to be a factor of five larger than the corresponding Balmer-line masses at CIV blueshifts of 3000 km/s and are over-estimated by almost an order of magnitude at the most extreme blueshifts, >5000 km/s. Using the monotonically increasing relationship between the CIV blueshift and the mass ratio BH(CIV)/BH(H$\alpha$) we derive an empirical correction to all CIV BH-masses. The scatter between the corrected CIV masses and the Balmer masses is 0.24 dex at low CIV blueshifts (~0 km/s) and just 0.10 dex at high blueshifts (~3000 km/s), compared to 0.40 dex before the correction. The correction depends only on the CIV line properties - i.e. full-width at half maximum and blueshift - and can therefore be applied to all quasars where CIV emission line properties have been measured, enabling the derivation of un-biased virial BH mass estimates for the majority of high-luminosity, high-redshift, spectroscopically confirmed quasars in the literature.Comment: Accepted for publication in MNRAS; fixed typo in CIV wavelengt

A mathematics peer assessment process for flexible modes of delivery

Educators have experienced significant challenges managing assessment processes over the last two years, particularly when converting in-person interactive and groupbased activities to an online format. This was of immediate concern during the initial stage of the Covid-19 pandemic, when interim measures for online assessment were introduced rapidly without the benefit of prior planning and design. As we emerge from the emergency phase of the pandemic, it appears there will be lasting changes to delivery and assessment in higher education, involving more hybrid and blended solutions. This paper discusses how an on-campus peer feedback assessment process for mathematics has been converted to a digital format to facilitate flexible modes of delivery either on-campus or online. A weekly paper-based peer-feedback process had been previously established in our large (150+) first-year engineering mathematics class. The new process involves weekly submission of work through the university Learning Management System (LMS), Canvas, which is peer marked by students using model video solutions for selected questions. Students complete a rubric and provide comments. After each session, students complete a reflective journal, considering their work over the week and the comments they have received. Engagement with the new flexible process has been shown to be comparable to the old system, while the quality of feedback given to peers in the online process is superior to those provided in the paper-based system. The system has been shown to be robust when rapid changes in delivery modes occur

The Interstellar Medium Properties of Heavily Reddened Quasars & Companions at z~2.5 with ALMA & JVLA

We study the interstellar medium (ISM) properties of three heavily reddened quasars at $z\sim2.5$ as well as three millimetre-bright companion galaxies near these quasars. New JVLA and ALMA observations constrain the CO(1-0), CO(7-6) and [CI]$^3$P$_2-^3$P$_1$ line emission as well as the far infrared to radio continuum. The gas excitation and physical properties of the ISM are constrained by comparing our observations to photo-dissociation region (PDR) models. The ISM in our high-redshift quasars is composed of very high-density, high-temperature gas which is already highly enriched in elements like carbon. One of our quasar hosts is shown to be a close-separation ($<$2 arcsec) major merger with different line emission properties in the millimeter-bright galaxy and quasar components. Low angular resolution observations of high-redshift quasars used to assess quasar excitation properties should therefore be interpreted with caution as they could potentially be averaging over multiple components with different ISM conditions. Our quasars and their companion galaxies show a range of CO excitation properties spanning the full extent from starburst-like to quasar-like spectral line energy distributions. We compare gas masses based on CO, CI and dust emission, and find that these can disagree when standard assumptions are made regarding the values of $\alpha_{\rm{CO}}$, the gas-to-dust ratio and the atomic carbon abundances. We conclude that the ISM properties of our quasars and their companion galaxies are diverse and likely vary spatially across the full extent of these complex, merging systems.Comment: Accepted for publication in MNRAS (18 pages, 10 figures and 5 tables