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| 2. |
- Aartsen, M. G., et al.
(författare)
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Very high-energy gamma-ray follow-up program using neutrino triggers from IceCube
- 2016
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Ingår i: Journal of Instrumentation. - 1748-0221. ; 11
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Tidskriftsartikel (refereegranskat)abstract
- We describe and report the status of a neutrino-triggered program in IceCube that generates real-time alerts for gamma-ray follow-up observations by atmospheric-Cherenkov telescopes (MAGIC and VERITAS). While IceCube is capable of monitoring the whole sky continuously, high-energy gamma-ray telescopes have restricted fields of view and in general are unlikely to be observing a potential neutrino-flaring source at the time such neutrinos are recorded. The use of neutrino-triggered alerts thus aims at increasing the availability of simultaneous multi-messenger data during potential neutrino flaring activity, which can increase the discovery potential and constrain the phenomenological interpretation of the high-energy emission of selected source classes (e. g. blazars). The requirements of a fast and stable online analysis of potential neutrino signals and its operation are presented, along with first results of the program operating between 14 March 2012 and 31 December 2015.
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| 3. |
- Abeysekara, A. U., et al.
(författare)
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A Luminous and Isolated Gamma-Ray Flare from the Blazar B2 1215+30
- 2017
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Ingår i: Astrophysical Journal. - : Institute of Physics Publishing (IOPP). - 0004-637X .- 1538-4357. ; 836:2
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Tidskriftsartikel (refereegranskat)abstract
- B2 1215+30 is a BL-Lac-type blazar that was first detected at TeV energies by the MAGIC atmospheric Cherenkov telescopes and subsequently confirmed by the Very Energetic Radiation Imaging Telescope Array System (VERITAS) observatory with data collected between 2009 and 2012. In 2014 February 08, VERITAS detected a large-amplitude flare from B2. 1215+30 during routine monitoring observations of the blazar 1ES. 1218+304, located in the same field of view. The TeV flux reached 2.4 times the Crab Nebula flux with a variability timescale of <3.6 hr. Multiwavelength observations with Fermi-LAT, Swift, and the Tuorla Observatory revealed a correlated high GeV flux state and no significant optical counterpart to the flare, with a spectral energy distribution where the gamma-ray luminosity exceeds the synchrotron luminosity. When interpreted in the framework of a onezone leptonic model, the observed emission implies a high degree of beaming, with Doppler factor delta > 10, and an electron population with spectral index p < 2.3.
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| 4. |
- Hakansson, M C, et al.
(författare)
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The electronic structure of In- and As-terminated InAs(001) surfaces
- 1997
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Ingår i: Surface Science. - 0039-6028 .- 1879-2758. ; 374:1-3, s. 73-79
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Tidskriftsartikel (refereegranskat)abstract
- The InAs(001) 2 x 4 and 4 x 2 surfaces have been investigated by angle-resolved photoemission. The X(3) and X(5) points were found to be located 6.0 and 2.7 eV below the valence band maximum, respectively, and the dispersion of bulk bands along the Gamma-X direction in the bulk Brillouin zone were well described by a theoretical calculation. From angle-resolved valence band spectra measured along the high symmetry directions [110] and [1(1) over bar0$], three surface induced stares were identified on both the InAs(001)4 x 2 and the InAs(001)2 x 4 surface. (C) 1997 Elsevier Science B.V.
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| 5. |
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| 6. |
- Andersson, C B M, et al.
(författare)
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Surface atomic structure of InAs((111)over-bar)2x2 and InSb((111)over-bar)2x2 studied by core level spectroscopy
- 1996
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Ingår i: Surface Science. - : Elsevier BV. - 0039-6028 .- 1879-2758. ; 347:1-2, s. 199-206
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Tidskriftsartikel (refereegranskat)abstract
- Surface sensitive high resolution core level spectroscopy has been applied to the molecular beam epitaxy grown InAs((111) over bar)2 x 2 and InSb((111) over bar)2 x 2 surfaces. For both systems the In 4d core level consists of one dominating component while the Group V core levels are deconvoluted into four components. This analysis is consistent with a surface model where the topmost layer consists entirely of arsenic or antimony. In this model, Group V atoms form trimers bound to Group V atoms in the first double layer, leaving a single Group V rest atom per unit cell.
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| 7. |
- Olsson, L O, et al.
(författare)
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Core level and valence-band studies of the (111)2x2 surfaces of InSb and InAs
- 1996
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Ingår i: Physical Review B Condensed Matter. - 0163-1829 .- 1095-3795. ; 53:8, s. 4734-4740
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Tidskriftsartikel (refereegranskat)abstract
- The valence and core electronic surface states on the (111)2X2 surfaces of InSb and InAs have been studied by angle-resolved photoelectron spectroscopy. Similarities in data show that the vacancy-buckling model, which is known to describe the InSb(111)2x2 surface, also applies to InAs(111)2X2. Three surface valence bands are identified and their dispersions are mapped along symmetry directions in the surface Brillouin zone. The In 4d core levels show one surface shifted component while no surface shifted components of the Sb 4d or As 3d core levels could be resolved.
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| 8. |
- ANDERSSON, CBM, et al.
(författare)
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SPUTTERED AND ANNEALED INAS(111)OVER-BAR - AN UNRECONSTRUCTED SURFACE
- 1994
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Ingår i: Surface Science. - : Elsevier BV. - 0039-6028 .- 1879-2758. ; 307, s. 885-889
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Tidskriftsartikel (refereegranskat)abstract
- The electronic structure of the InAs(111BAR)1 X 1 surface has been investigated by angle resolved photoelectron spectroscopy along the symmetry lines GAMMAKBAR, GAMMAMBAR, and GAMMAMBAR of the surface Brillouin zone. The bulk valence band structure was calculated using a combination of the linear augmented plane-wave method and the relativistic augmented plane-wave method. We have projected the theoretical bulk band structure onto the surface Brillouin zone to separate surface states from surface resonances. Two surface related structures, S1 and S2, have been observed and their E(i)(k(parallel-to)) dispersions are established. Both S1 and S2 show the symmetry of the 1 X 1 surface Brillouin zone, which is consistent with the observed 1 X 1 LEED pattern. We identify S1 as the As-derived dangling bond state, and S2 is associated with the backbonds connecting the As atoms in the surface layer with the underlying In layer.
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| 9. |
- Eriksson, P, et al.
(författare)
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Neonatal exposure to DDT and its fatty acid conjugate: effects on cholinergic and behavioural variables in the adult mouse
- 1990
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Ingår i: NeuroToxicology. - 1872-9711. ; 11:2, s. 345-354
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Tidskriftsartikel (refereegranskat)abstract
- We have recently observed that DDT and a DDT metabolite, DDOH, conjugated to a fatty acid, palmitic acid, DDOH-PA, affects muscarinic cholinergic receptors (MAChR) in the neonatal mouse brain when given to suckling mice during rapid brain growth. This early exposure of the neonatal mouse also affects the behaviour of the animals as adults. When DDT and DDOH-PA was given as a single low oral dose of 1.4 mumol/kg body weight, DDT (0.5 mg), DDOH-PA (0.7 mg) and a 20% fat emulsion vehicle (10 ml) per kg body weight to 10-day-old NMRI mice, behavioural tests at adult age of four months, indicated disruption of a simple, non-associative learning process, i.e. habituation, in both DDT and DDOH-PA treated mice. There was also a significant increase in the potassium evoked release of ACh from slices of cerebral cortex and a tendency towards a decrease in the density of MAChR in mice receiving DDT. These effects in the adult mice could not be correlated to the concentration of DDT in the adult brain since DDT one month after its administration to the 10-day-old mouse no longer is present in the brain.
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| 10. |
- OLSSON, LO, et al.
(författare)
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ANOMALOUS QUENCHING OF PHOTOEMISSION FROM BULK STATES BY DEPOSITION OF CS ON INAS(100)
- 1995
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Ingår i: Physical Review B Condensed Matter. - 0163-1829 .- 1095-3795. ; 52:3, s. 1470-1473
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Tidskriftsartikel (refereegranskat)abstract
- The effect of angle-resolved valence-hand photoelectron spectra from adsorption of small amounts of Cs on InAs(100)4 X 2 has been studied. It is shown that a bulk interband transition is totally quenched at a coverage of Cs that leaves the 4 X 2 reconstruction practically intact. The surface order was monitored by low-energy electron diffraction and photoemission from surface states. A shift of the surface Fermi level to well above the conduction-band minimum is also observed. It is proposed that the resulting development of a two-dimensional electron gas at the surface affects the bulk states probed in photoemission.
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| 11. |
- OLSSON, LO, et al.
(författare)
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SURFACE ELECTRONIC-STRUCTURE OF INSB(100)4X1 STUDIED BY ANGLE-RESOLVED PHOTOELECTRON-SPECTROSCOPY
- 1995
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Ingår i: Surface Science. - : Elsevier BV. - 0039-6028 .- 1879-2758. ; 331, s. 1176-1180
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Tidskriftsartikel (refereegranskat)abstract
- The surface electronic structure of the In-rich InSb(100)4 X 1 surface has been studied by angle-resolved photoelectron spectroscopy. To determine the origin of different contributions in spectra, direct bulk interband transitions were first identified using a semi-empirical band structure calculation and assuming direct transitions into free electron-like final bands. Three surface-induced features were identified and their dispersions have been mapped along symmetry directions of the surface Brillouin zone.
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