| 1. |
- Graslund, S, et al.
(författare)
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Protein production and purification
- 2008
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Ingår i: Nature methods. - : Springer Science and Business Media LLC. - 1548-7105 .- 1548-7091. ; 5:2, s. 135-146
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Tidskriftsartikel (refereegranskat)
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| 2. |
- Cristina Baglio, Maria, et al.
(författare)
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A Wildly Flickering Jet in the Black Hole X-Ray Binary MAXI J1535-571
- 2018
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Ingår i: Astrophysical Journal. - : American Astronomical Society. - 1538-4357 .- 0004-637X. ; 867:2
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Tidskriftsartikel (refereegranskat)abstract
- We report on the results of optical, near-infrared (NIR), and mid-infrared observations of the black hole X-ray binary candidate (BHB) MAXI J1535-571 during its 2017/2018 outburst. During the first part of the outburst (MJD 58004-58012), the source shows an optical-NIR spectrum that is consistent with an optically thin synchrotron power law from a jet. After MJD 58015, however, the source faded considerably, the drop in flux being much more evident at lower frequencies. Before the fading, we measure a dereddened flux density of 100 mJy in the mid-infrared, making MAXI J1535-571 one of the brightest mid-infrared BHBs known so far. A significant softening of the X-ray spectrum is evident contemporaneous with the infrared fade. We interpret it as being due to the suppression of the jet emission, similar to the accretion-ejection coupling seen in other BHBs. However, MAXI J1535-571 did not transition smoothly to the soft state, instead showing X-ray hardness deviations associated with infrared flaring. We also present the first mid-IR variability study of a BHB on minute timescales, with a fractional rms variability of the light curves of ∼15%-22%, which is similar to that expected from the internal shock jet model, and much higher than the optical fractional rms (≲7%). These results represent an excellent case of multiwavelength jet spectral timing and demonstrate how rich, multiwavelength time-resolved data of X-ray binaries over accretion state transitions can help in refining models of the disk-jet connection and jet launching in these systems.
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| 3. |
- Merabet, S., et al.
(författare)
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A structurally plastic extension of the homeodomain recognition helix orchestrates central Hox protein activity
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Annan publikation (övrigt vetenskapligt/konstnärligt)abstract
- Protein function is encoded within the amino acid coding sequence and the variation in this sequence, and subsequent structure, provide the bases for functional diversification at the molecular and organismal levels. However, how separate protein domainscooperate to build protein activity remains largely unknown. Focusing on three domains of central Hox transcription factors, we mutagenized combinations of their domains to investigate their intrinsic functional organization. Our results demonstrate a high degree of domain interactivity, with an orchestrating role of a structurally plastic C-terminal extension of the homeodomain (HD). This domain provides, in a folding dependant manner, a topologically constrained contact with the Hox cofactor Extradenticle, which impacts the positioning of the recognition helix in the major groove of DNA. These findings provide novel insights in HD/DNA target recognition and, given the phylogeny of this C-terminal extension, also shed light on the molecular bases underlying the functional diversification of paralogous Hox families.
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| 4. |
- Paice, J. A., et al.
(författare)
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The evolution of rapid optical/X-ray timing correlations in the initial hard state of MAXIJ1820+070
- 2021
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Ingår i: Monthly notices of the Royal Astronomical Society. - : Oxford University Press (OUP). - 0035-8711 .- 1365-2966. ; 505:3, s. 3452-3469
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Tidskriftsartikel (refereegranskat)abstract
- We report on a multiepoch campaign of rapid optical/X-ray timing observations of the superbright 2018 outburst of MAXIJ1820+070, a black hole low-mass X-ray binary system. The observations spanned 80 d in the initial hard state and were taken with NTT/ULTRACAM and GTC/HiPERCAM in the optical (u(s)g(s)r(s)i(s)z(s) filters at time resolutions of 8-300Hz) and with ISS/NICER in X-rays. We find (i) a growing anticorrelation between the optical and X-ray light curves, (ii) a steady, positive correlation at an optical lag of similar to 0.2s (with a longer lag at longer wavelengths) present in all epochs, and (iii) a curious positive correlation at negative optical lags in the last, X-ray softest epoch, with longer wavelengths showing a greater correlation and a more negative lag. To explain these, we postulate the possible existence of two synchrotron-emitting components - a compact jet and a hot flow. In our model, the significance of the jet decreases over the outburst, while the hot flow remains static (thus, relatively, increasing in significance). We also discuss a previously discovered quasi-periodic oscillation and note how it creates coherent optical time lags, stronger at longer wavelengths, during at least two epochs.
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| 6. |
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| 7. |
- Törngren, Martin, 1963-, et al.
(författare)
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Characterization, Analysis, and Recommendations for Exploiting the Opportunities of Cyber-Physical Systems
- 2016
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Ingår i: Cyber-Physical Systems: Foundations, Principles and Applications. - : Elsevier. - 9780128038741 - 9780128038017 ; , s. 3-14
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Bokkapitel (refereegranskat)abstract
- Leveraging on a comprehensive analysis of cyber-physical systems (CPSs) in Europe, this chapter presents overall findings focusing on (1) a characterization of CPS, (2) opportunities and challenges in representative CPS application domains, and (3) recommendations for action resulting from a cross-domain analysis. The characterization enables a high-level description of a CPS, or classes of CPS, according to their technical emphasis, cross-cutting aspects, level of automation, and life-cycle integration. We illustrate how these characteristics can be used to relate to design issues, systems, and related terms.The recommendations are to: (1) strengthen cross-disciplinary research collaboration, (2) foster CPS education and training, (3) stimulate public-private partnerships for CPS technology experimentation and to ensure dependable information and communication technology (ICT) infrastructure, (4) promote interoperability of CPS technology, (5) anticipate new business models and support open innovation, (6) ensure trustworthiness including safety and security, and (7) favor human-centered approaches to CPS.
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| 8. |
- Vincentelli, Federico M., et al.
(författare)
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A shared accretion instability for black holes and neutron stars
- 2023
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Ingår i: Nature. - : Springer Science and Business Media LLC. - 0028-0836 .- 1476-4687. ; 615:7950, s. 45-49
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Tidskriftsartikel (refereegranskat)abstract
- Accretion disks around compact objects are expected to enter an unstable phase at high luminosity1. One instability may occur when the radiation pressure generated by accretion modifies the disk viscosity, resulting in the cyclic depletion and refilling of the inner disk on short timescales2. Such a scenario, however, has only been quantitatively verified for a single stellar-mass black hole3-5. Although there are hints of these cycles in a few isolated cases6-10, their apparent absence in the variable emission of most bright accreting neutron stars and black holes has been a continuing puzzle11. Here we report the presence of the same multiwavelength instability around an accreting neutron star. Moreover, we show that the variability across the electromagnetic spectrum-from radio to X-ray-of both black holes and neutron stars at high accretion rates can be explained consistently if the accretion disks are unstable, producing relativistic ejections during transitions that deplete or refill the inner disk. Such a new association allows us to identify the main physical components responsible for the fast multiwavelength variability of highly accreting compact objects.
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| 9. |
- Vincentelli, F. M., et al.
(författare)
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Fast infrared variability from the black hole candidate MAXI J1535-571 and tight constraints on the modelling
- 2021
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Ingår i: Monthly notices of the Royal Astronomical Society. - : Oxford University Press (OUP). - 0035-8711 .- 1365-2966. ; 503:1, s. 614-624
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Tidskriftsartikel (refereegranskat)abstract
- We present the results regarding the analysis of the fast X-ray/infrared (IR) variability of the black hole transient MAXI J1535-571. The data studied in thiswork consist of two strictly simultaneous observations performed with XMM-Newton (X-rays: 0.7-10 keV), VLT/HAWK-I (K-s band, 2.2 mu m) andVLT/VISIR (Mand PAH2 2 bands, 4.85 and 11.88 mu m, respectively). The cross-correlation function between the X-ray and near-IR light curves shows a strong asymmetric anticorrelation dip at positive lags. We detect a near-IR QPO (2.5 sigma) at 2.07 +/- 0.09 Hz simultaneously with an X-ray QPO at approximately the same frequency (f(0) = 2.25 +/- 0.05). From the cross-spectral analysis, a lag consistent with zero was measured between the two oscillations. We also measure a significant correlation between the average near-IR and mid-IR fluxes during the second night, but find no correlation on short time-scales. We discuss these results in terms of the two main scenarios for fast IR variability (hot inflow and jet powered by internal shocks). In both cases, our preliminary modelling suggests the presence of a misalignment between the disc and jet.
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