| 1. |
- Abdelhameed, A. H., et al.
(författare)
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First results on sub-GeV spin-dependent dark matter interactions with Li-7
- 2019
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Ingår i: European Physical Journal C. - : Springer Science and Business Media LLC. - 1434-6044 .- 1434-6052. ; 79:7
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Tidskriftsartikel (refereegranskat)abstract
- In this work, we want to highlight the potential of lithium as a target for spin-dependent dark matter search in cryogenic experiments, with a special focus on the low-mass region of the parameter space. We operated a prototype detector module based on a Li2MoO4 target crystal in an above-ground laboratory. Despite the high background environment, the detector sets a competitive limit on spin-dependent interactions of dark matter particles with protons and neutrons for masses between 1.5 GeV/c(2).
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| 2. |
- Abdelhameed, A. H., et al.
(författare)
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First results from the CRESST-III low-mass dark matter program
- 2019
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Ingår i: Physical Review D. - 2470-0010 .- 2470-0029. ; 100:10
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Tidskriftsartikel (refereegranskat)abstract
- The CRESST experiment is a direct dark matter search which aims to measure interactions of potential dark matter particles in an Earth-bound detector. With the current stage, CRESST-III, we focus on a low energy threshold for increased sensitivity towards light dark matter particles. In this paper we describe the analysis of one detector operated in the first run of CRESST-III (05/2016-02/2018) achieving a nuclear recoil threshold of 30.1 eV. This result was obtained with a 23.6 g CaWO4 crystal operated as a cryogenic scintillating calorimeter in the CRESST setup at the Laboratori Nazionali del Gran Sasso (LNGS). Both the primary phonon (heat) signal and the simultaneously emitted scintillation light, which is absorbed in a separate silicon-on-sapphire light absorber, are measured with highly sensitive transition edge sensors operated at similar to 15 mK. The unique combination of these sensors with the light element oxygen present in our target yields sensitivity to dark matter particle masses as low as 160 MeV/c(2).
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| 3. |
- Abdelhameed, A. H., et al.
(författare)
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Geant4-based electromagnetic background model for the CRESST dark matter experiment
- 2019
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Ingår i: European Physical Journal C. - : Springer Science and Business Media LLC. - 1434-6044 .- 1434-6052. ; 79:10
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Tidskriftsartikel (refereegranskat)abstract
- The CRESST (Cryogenic Rare Event Search with Superconducting Thermometers) dark matter search experiment aims for the detection of dark matter particles via elastic scattering off nuclei in CaWO4 crystals. To understand the CRESST electromagnetic background due to the bulk contamination in the employed materials, a model based on Monte Carlo simulations was developed using the Geant4 simulation toolkit. The results of the simulation are applied to the TUM40 detector module of CRESST-II phase 2. We are able to explain up to (68 +/- 16)% of the electromagnetic background in the energy range between 1 and 40 keV.
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| 4. |
- Angloher, G., et al.
(författare)
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Limits on dark matter effective field theory parameters with CRESST-II
- 2019
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Ingår i: European Physical Journal C. - : Springer Science and Business Media LLC. - 1434-6044 .- 1434-6052. ; 79:1
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Tidskriftsartikel (refereegranskat)abstract
- CRESST is a direct dark matter search experiment, aiming for an observation of nuclear recoils induced by the interaction of dark matter particles with cryogenic scintillating calcium tungstate crystals. Instead of confining ourselves to standard spin-independent and spin-dependent searches, we re-analyze data from CRESST-II using a more general effective field theory (EFT) framework. On many of the EFT coupling constants, improved exclusion limits in the low-mass region (< 3–4 GeV/c2) are presented.
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| 5. |
- Bento, J., et al.
(författare)
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HATS-22b, HATS-23b and HATS-24b : three new transiting super-Jupiters from the HATSouth project
- 2017
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Ingår i: Monthly notices of the Royal Astronomical Society. - : Oxford University Press (OUP). - 0035-8711 .- 1365-2966. ; 468:1, s. 835-848
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Tidskriftsartikel (refereegranskat)abstract
- We report the discovery of three moderately high-mass transiting hot Jupiters from the HATSouth survey: HATS-22b, HATS-23b and HATS-24b. These planets add to the number of known planets in the similar to 2MJ regime. HATS-22b is a 2.74 +/- 0.11MJ mass and 0.953(-0.029)(+0.048) R-J radius planet orbiting a V = 13.455 +/- 0.040 sub-solar mass (M-* = 0.759 +/- 0.019M(circle dot); R-* = 0.759 +/- 0.019 R-circle dot) K-dwarf host star on an eccentric (e = 0.079 +/- 0.026) orbit. This planet's high planet-to-stellar mass ratio is further evidence that migration mechanisms for hot Jupiters may rely on exciting orbital eccentricities that bring the planets closer to their parent stars followed by tidal circularization. HATS-23b is a 1.478 +/- 0.080M(J) mass and 1.69 +/- 0.24 R-J radius planet on a grazing orbit around a V = 13.901 +/- 0.010 G-dwarf with properties very similar to those of the Sun (M* = 1.115 +/- 0.054; R-* = 1.145 +/- 0.070). HATS24b orbits a moderately bright V = 12.830 +/- 0.010 F-dwarf star (M-* = 1.218 +/- 0.036M circle dot; R-* = 1.194(-0.041)(+0.066) R circle dot). This planet has a mass of 2.39+0.21 -0.12MJ and an inflated radius of 1.516(-0.065)(+0.085) R-J.
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| 6. |
- de Val-Borro, M., et al.
(författare)
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HATS-31B THROUGH HATS-35B : FIVE TRANSITING HOT JUPITERS DISCOVERED BY THE HATSOUTH SURVEY
- 2016
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Ingår i: Astronomical Journal. - : American Astronomical Society. - 0004-6256 .- 1538-3881. ; 152:6
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Tidskriftsartikel (refereegranskat)abstract
- We report the discovery of five new transiting hot-Jupiter planets discovered by the HATSouth survey, HATS-31b through HATS-35b. These planets orbit moderately bright stars with V magnitudes within the range of 11.9-14.4 mag while the planets span a range of masses of. 0.88-1.22 M-J. and have somewhat inflated radii between 1.23 and 1.64 R-J. These planets can be classified as typical hot Jupiters, with HATS-31b and HATS-35b being moderately inflated gas giant planets with radii of 1.64 +/- 0.22 R-J and 1.464(-0.044)(+0.069) R-J, respectively, that can be used to constrain inflation mechanisms. All five systems present a higher Bayesian evidence for a fixed-circular-orbit model than for an eccentric orbit. The orbital periods range from 1.8209993 +/- 0.0000016 day for HATS-35b) to 3.377960 +/- 0.000012 day for HATS-31b. Additionally, HATS-35b orbits a relatively young F star with an age of 2.13 +/- 0.51 Gyr. We discuss the analysis to derive the properties of these systems and compare them in the context of the sample of well-characterized transiting hot Jupiters known to date.
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| 7. |
- Henning, Th., et al.
(författare)
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HATS-50b through HATS-53b : Four Transiting Hot Jupiters Orbiting G-type Stars Discovered by the HATSouth Survey
- 2018
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Ingår i: Astronomical Journal. - : American Astronomical Society. - 0004-6256 .- 1538-3881. ; 155:2
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Tidskriftsartikel (refereegranskat)abstract
- We report the discovery of four close-in transiting exoplanets (HATS-50b through HATS-53b), discovered using the HATSouth three-continent network of homogeneous and automated telescopes. These new exoplanets belong to the class of hot Jupiters and orbit G-type dwarf stars, with brightness in the range V = 12.5-14.0 mag. While HATS-53 has many physical characteristics similar to the Sun, the other three stars appear to be metal-rich ([Fe/H]= 0.2-0.3), larger, and more massive. Three of the new exoplanets, namely HATS-50b, HATS-51b, and HATS-53b, have low density (HATS-50b: 0.39 +/- 0.10 M-J, 1.130 +/- 0.075 R-J; HATS-51b: 0.768 +/- 0.045 M-J, 1.41 +/- 0.19 R-J; HATS-53b: 0.595 +/- 0.089 M-J, 1.340 +/- 0.056 R-J) and similar orbital periods (3.8297 days, 3.3489 days, 3.8538 days, respectively). Instead, HATS-52b is more dense (mass 2.24. +/- 0.15 M-J and radius 1.382 +/- 0.086 R-J) and has a shorter orbital period (1.3667 days). It also receives an intensive radiation from its parent star and, consequently, presents a high equilibrium temperature (T-eq = 1834 +/- 73 K). HATS-50 shows a marginal additional transit feature consistent with an ultra-short-period hot super Neptune (upper mass limit 0.16 M-J), which will be able to be confirmed with TESS photometry.
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| 8. |
- Meyer, Heather M, et al.
(författare)
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Fluctuations of the transcription factor ATML1 generate the pattern of giant cells in the Arabidopsis sepal
- 2017
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Ingår i: eLife. - 2050-084X.
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Tidskriftsartikel (refereegranskat)abstract
- Multicellular development produces patterns of specialized cell types. Yet, it is often unclear how individual cells within a field of identical cells initiate the patterning process. Using live imaging, quantitative image analyses and modeling, we show that during Arabidopsis thaliana sepal development, fluctuations in the concentration of the transcription factor ATML1 pattern a field of identical epidermal cells to differentiate into giant cells interspersed between smaller cells. We find that ATML1 is expressed in all epidermal cells. However, its level fluctuates in each of these cells. If ATML1 levels surpass a threshold during the G2 phase of the cell cycle, the cell will likely enter a state of endoreduplication and become giant. Otherwise, the cell divides. Our results demonstrate a fluctuation-driven patterning mechanism for how cell fate decisions can be initiated through a random yet tightly regulated process.
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