| 1. |
- Acharya, B. S., et al.
(författare)
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Introducing the CTA concept
- 2013
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Ingår i: Astroparticle physics. - : Elsevier BV. - 0927-6505 .- 1873-2852. ; 43, s. 3-18
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Tidskriftsartikel (övrigt vetenskapligt/konstnärligt)abstract
- The Cherenkov Telescope Array (CTA) is a new observatory for very high-energy (VHE) gamma rays. CTA has ambitions science goals, for which it is necessary to achieve full-sky coverage, to improve the sensitivity by about an order of magnitude, to span about four decades of energy, from a few tens of GeV to above 100 TeV with enhanced angular and energy resolutions over existing VHE gamma-ray observatories. An international collaboration has formed with more than 1000 members from 27 countries in Europe, Asia, Africa and North and South America. In 2010 the CTA Consortium completed a Design Study and started a three-year Preparatory Phase which leads to production readiness of CTA in 2014. In this paper we introduce the science goals and the concept of CTA, and provide an overview of the project. (C) 2013 Elsevier B.V. All rights reserved.
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| 2. |
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| 3. |
- Muller, Sebastien, 1976, et al.
(författare)
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An ALMA Early Science survey of molecular absorption lines toward PKS 1830-211 Analysis of the absorption profiles
- 2014
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Ingår i: Astronomy and Astrophysics. - : EDP Sciences. - 0004-6361 .- 1432-0746. ; 566
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Tidskriftsartikel (refereegranskat)abstract
- We present the first results of an ALMA spectral survey of strong absorption lines for common interstellar species in the z = 0.89 molecular absorber toward the lensed blazar PKS 1830-211. The dataset brings essential information on the structure and composition of the absorbing gas in the foreground galaxy. In particular, we find absorption over large velocity intervals (greater than or similar to 100 km s(-1)) toward both lensed images of the blazar. This suggests either that the galaxy inclination is intermediate and that we sample velocity gradients or streaming motions in the disk plane, that the molecular gas has a large vertical distribution or extraplanar components, or that the absorber is not a simple spiral galaxy but might be a merger system. The number of detected species is now reaching a total of 42 different species plus 14 different rare isotopologues toward the SW image, and 14 species toward the NE line-of-sight. The abundances of CH, H2O, HCO+, HCN, and NH3 relative to H-2 are found to be comparable to those in the Galactic diffuse medium. Of all the lines detected so far toward PKS 1830-211, the ground-state line of ortho-water has the deepest absorption. We argue that ground-state lines of water have the best potential for detecting diffuse molecular gas in absorption at high redshift.
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| 4. |
- Marti-Vidal, Ivan, 1980, et al.
(författare)
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Probing the jet base of the blazar PKS 1830-211 from the chromatic variability of its lensed images. Serendipitous ALMA observations of a strong gamma-ray flare
- 2013
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Ingår i: Astronomy and Astrophysics. - : EDP Sciences. - 0004-6361 .- 1432-0746. ; 558, s. 123-
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Tidskriftsartikel (refereegranskat)abstract
- The launching mechanism of the jets of active galactic nuclei is poorly constrained observationally, owing to the large distances to these objects and the very small scales (sub-parsec) involved. To better constrain theoretical models, it is especially important to get information from the region close to the physical base of the jet, where the plasma acceleration takes place. In this paper, we report multi-epoch and multifrequency continuum observations of the z = 2.5 blazar PKS 1830−211 with ALMA, serendipitously coincident with a strong γ-ray flare reported by Fermi-LAT. The blazar is lensed by a foreground z = 0.89 galaxy, with two bright images of the compact core separated by 1′′. Our ALMA observations individually resolve these two images (although not any of their substructures), and we study the change in their relative flux ratio with time (four epochs spread over nearly three times the time delay between the two lensed images) and frequency (between 350 and 1050 GHz, rest frame of the blazar), during the γ-ray flare. In particular, we detect a remarkable frequency-dependent behavior of the flux ratio, which implies the presence of a chromatic structure in the blazar (i.e., a core-shift effect). We rule out the possibility of micro- and milli-lensing effects and propose instead a simple model of plasmon ejection in the blazar’s jet to explain the time and frequency variability of the flux ratio. We suggest that PKS 1830−211 is likely to be one of the best sources to probe the activity at the base of a blazar’s jet at submillimeter wavelengths, thanks to the peculiar geometry of the system. The implications of the core shift in absorption studies of the foreground z = 0.89 galaxy (e.g., constraints on the cosmological variations of fundamental constants) are discussed.
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| 5. |
- Molin, Anna-Maja, et al.
(författare)
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A novel microdeletion syndrome at 3q13.31 characterised by developmental delay, postnatal overgrowth, hypoplastic male genitals, and characteristic facial features
- 2012
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Ingår i: Journal of Medical Genetics. - : BMJ. - 0022-2593 .- 1468-6244. ; 49:2, s. 104-109
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Tidskriftsartikel (refereegranskat)abstract
- Background Congenital deletions affecting 3q11q23 have rarely been reported and only five cases have been molecularly characterised. Genotype. phenotype correlation has been hampered by the variable sizes and breakpoints of the deletions. In this study, 14 novel patients with deletions in 3q11q23 were investigated and compared with 13 previously reported patients. Methods Clinical data were collected from 14 novel patients that had been investigated by high resolution microarray techniques. Molecular investigation and updated clinical information of one cytogenetically previously reported patient were also included. Results The molecular investigation identified deletions in the region 3q12.3q21.3 with different boundaries and variable sizes. The smallest studied deletion was 580 kb, located in 3q13.31. Genotype. phenotype comparison in 24 patients sharing this shortest region of overlapping deletion revealed several common major characteristics including significant developmental delay, muscular hypotonia, a high arched palate, and recognisable facial features including a short philtrum and protruding lips. Abnormal genitalia were found in the majority of males, several having micropenis. Finally, a postnatal growth pattern above the mean was apparent. The 580 kb deleted region includes five RefSeq genes and two of them are strong candidate genes for the developmental delay: DRD3 and ZBTB20. Conclusion A newly recognised 3q13.31 microdeletion syndrome is delineated which is of diagnostic and prognostic value. Furthermore, two genes are suggested to be responsible for the main phenotype.
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| 6. |
- Muller, Sebastien, 1976, et al.
(författare)
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Detection of chloronium and measurement of the Cl-35/Cl-37 isotopic ratio at z=0.89 toward PKS 1830-211
- 2014
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Ingår i: Astronomy and Astrophysics. - : EDP Sciences. - 0004-6361 .- 1432-0746. ; 566
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Tidskriftsartikel (refereegranskat)abstract
- We report the first extragalactic detection of chloronium (H2Cl+) in the z = 0.89 absorber in front of the lensed blazar PKS 1830-211. The ion is detected through its 1(11)-0(00) line along two independent lines of sight toward the North-East and South-West images of the blazar. The relative abundance of H2Cl+ is significantly higher (by a factor similar to 7) in the NE line of sight, which has a lower H-2/H fraction, indicating that H2Cl+ preferably traces the diffuse gas component. From the ratio of the (H2Cl+)-Cl-35 and (H2Cl+)-Cl-37 absorptions toward the SW image, we measure a Cl-35/Cl-37 isotopic ratio of 3.1(-0.2)(+0.3) at z = 0.89, similar to that observed in the Galaxy and the solar system.
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| 7. |
- Schultz, J. A., et al.
(författare)
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What is an endangered species worth? Threshold costs for protecting imperilled fishes in Canada
- 2013
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Ingår i: Marine Policy. - : Elsevier BV. - 0308-597X. ; 42, s. 125-132
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Tidskriftsartikel (refereegranskat)abstract
- The protection of imperilled fish species is increasingly urgent given ongoing fisheries declines and the degradation of aquatic habitats. In Canada, threatened aquatic species were less likely than terrestrial species to be listed under the Species at Risk Act (SARA), the main legal instrument for bestowing protection, in the early years of the Act's implementation. In this paper, the existence of economic thresholds that might have hampered the protection of Canadian marine and freshwater fishes is examined. The analysis of the socio-economic data used to inform listing decisions about threatened fish taxa over the past decade reveals that the likelihood of being listed declines non-linearly with increasing estimated costs of protection but does not vary with proposed threat status. The estimated threshold cost (i.e., the point at which the likelihood of not being listed=0.5) was ∼$5,000,000 (∼$1,400,000 to ∼$31,400,000, 95% CI) per decade for freshwater species but only ∼$90,000 ($∼50,000 to ∼$140,000, 95% CI) per decade for marine fish taxa. In fact, no marine fish species with an anticipated cost of listing greater than zero was listed for protection. The presence of existing management legislation and qualitative statements about negative impacts of listing on exploitation generally led to denying protection to marine but not to freshwater species. These findings highlight both a large and inconsistent emphasis on costs of protection in SARA listing decisions, to the detriment of marine fish species.
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