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- Deka, P. P., et al.
(författare)
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The MeerKAT Absorption Line Survey (MALS) Data Release. I. Stokes I Image Catalogs at 1-1.4 GHz
- 2024
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Ingår i: Astrophysical Journal, Supplement Series. - 1538-4365 .- 0067-0049. ; 270:2
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Tidskriftsartikel (refereegranskat)abstract
- The MeerKAT Absorption Line Survey (MALS) has observed 391 telescope pointings at the L band (900-1670 MHz) at delta less than or similar to +20 degrees. We present radio continuum images and a catalog of 495,325 (240,321) radio sources detected at a signal-to-noise ratio (S/N) > 5 over an area of 2289 deg(2) (1132 deg(2)) at 1006 MHz (1381 MHz). Every MALS pointing contains a central bright radio source (S 1 GHz greater than or similar to 0.2 Jy). The median spatial resolution is 12 ''(8 ''). The median rms noise away from the pointing center is 25 mu Jy beam(-1) (22 mu Jy beam-1) and is within similar to 15% of the achievable theoretical sensitivity. The flux density scale ratio and astrometric accuracy deduced from multiply observed sources in MALS are <1% (8% scatter) and 1 '', respectively. Through comparisons with NVSS and FIRST at 1.4 GHz, we establish the catalog's accuracy in the flux density scale and astrometry to be better than 6% (15% scatter) and 0.'' 8, respectively. The median flux density offset is higher (9%) for an alternate beam model based on holographic measurements. The MALS radio source counts at 1.4 GHz are in agreement with literature. We estimate spectral indices (alpha) of a subset of 125,621 sources (S/N > 8), confirm the flattening of spectral indices with decreasing flux density, and identify 140 ultra-steep-spectrum (alpha < -1.3) sources as prospective high-z radio galaxies (z > 2). We have identified 1308 variable and 122 transient radio sources comprising primarily active galactic nuclei that demonstrate long-term (26 yr) variability in their observed flux densities. The MALS catalogs and images are publicly available at https://mals.iucaa.in.
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| 4. |
- Öman, Cecilia B., et al.
(författare)
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Strategy for strengthening scientific capacity in developing countries on water and sanitation related issues
- 2009
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Ingår i: Desalination. - : Elsevier BV. - 0011-9164 .- 1873-4464. ; 248:1-3, s. 658-665
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Tidskriftsartikel (refereegranskat)abstract
- It is generally accepted that scientific research offers a tool for meeting the development demands in the area of water and sanitation. It is stressed by the authors that research should be performed by researchers in the countries most affected, on topics identified by these researchers and in their own environment. For researchers in developing countries the resources and scientific infrastructure constitutes a hindrance to scientific research. To address the situation this paper presents a strategy for scientific capacity strengthening. The strategy builds on a number of activities including; training courses on scientific methodology, literature review, fundraising, sampling, laboratory practices, statistical methods, experimental designs, participatory approaches, oral presentation, posters and manuscript development, as well as thematic workshops, workshop for revision of proposals, contacts with end-users, research grants, networks, purchasing and maintaining scientific equipment and scientific conferences. The strategy builds heavily on collaboration with local organisations. It has been concluded through assessments of activities arranged in Bangladesh, Benin, Burkina Faso, Cameroon, Ivory Coast, Ghana, Mali, Niger, Nigeria, Nepal, Sri Lanka and Togo that the strategy has been successful.
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