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1. From spherical stars to disk-like structures: 3D common-envelope evolution of massive binaries beyond inspiral

Author

Vetter, M., Roepke, F. K., Schneider, F. R. N., Pakmor, R., Ohlmann, S. T., Lau, M. Y. M., and Andrassy, R.

Subjects
Astrophysics - Solar and Stellar Astrophysics, Astrophysics - High Energy Astrophysical Phenomena, General Relativity and Quantum Cosmology
Abstract

Three-dimensional simulations usually fail to cover the entire dynamical common-envelope phase of gravitational wave progenitor systems due to the vast range of spatial and temporal scales involved. We investigated the common-envelope interactions of a $10\,M_\odot$ red supergiant primary star with a black hole and a neutron star companion, respectively, until full envelope ejection (${\gtrsim}\,97 \,\mathrm{\%}$ of the envelope mass). We find that the dynamical plunge-in of the systems determines largely the orbital separations of the core binary system, while the envelope ejection by recombination acts only at later stages of the evolution and fails to harden the core binaries down to orbital frequencies where they qualify as progenitors of gravitational-wave-emitting double-compact object mergers. As opposed to the conventional picture of a spherically symmetric envelope ejection, our simulations show a new mechanism: The rapid plunge-in of the companion transforms the spherical morphology of the giant primary star into a disk-like structure. During this process, magnetic fields are amplified, and the subsequent transport of material through the disk around the core binary system drives a fast jet-like outflow in the polar directions. While most of the envelope material is lost through a recombination-driven wind from the outer edge of the disk, about $7\,\mathrm{\%}$ of the envelope leaves the system via the magnetically driven outflows. We further explored the potential evolutionary pathways of the post-common-envelope systems given the expected remaining lifetime of the primary core ($2.97\,M_\odot$) until core collapse ($6{\times}10^{4}\,\mathrm{yr}$), most likely forming a neutron star. We find that the interaction of the core binary system with the circumbinary disk increases the likelihood of giving rise to a double-neutron star merger. (abridged), Comment: 17 Pages, 9 Figures, accepted by A&A

Published
2024
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3. Rejuvenated accretors have less bound envelopes: Impact of Roche lobe overflow on subsequent common envelope events

Author

Renzo, M., Zapartas, E., Justham, S., Breivik, K., Lau, M., Farmer, R., Cantiello, M., and Metzger, B. D.

Subjects
Astrophysics - Solar and Stellar Astrophysics, Astrophysics - High Energy Astrophysical Phenomena
Abstract

Common-envelope (CE) evolution is an outstanding open problem in stellar evolution, critical to the formation of compact binaries including gravitational-wave sources. In the ``classical'' isolated binary evolution scenario for double compact objects, the CE is usually the second mass transfer phase. Thus, the donor star of the CE is the product of a previous binary interaction, often stable Roche-lobe overflow (RLOF). Because of the accretion of mass during the first RLOF, the main-sequence core of the accretor star grows and is ``rejuvenated''. This modifies the core-envelope boundary region and decreases significantly the envelope binding energy for the remaining evolution. Comparing accretor stars from self-consistent binary models to stars evolved as single, we demonstrate that the rejuvenation can lower the energy required to eject a CE by $\sim 42-96\%$ for both black hole and neutron star progenitors, depending on the evolutionary stage and final orbital separation. Therefore, binaries experiencing first stable mass transfer may more easily survive subsequent CE events and result in possibly wider final separations compared to current predictions. Despite their high mass, our accretors also experience extended ``blue loops'', which may have observational consequences for low-metallicity stellar populations and asteroseismology., Comment: accepted for publication in ApJL, reproducible at https://github.com/mathren/CE_accretors

Published
2022
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7. Space Telescope and Optical Reverberation Mapping Project. XII. Broad-Line Region Modeling of NGC 5548

Author

Williams, P. R., Pancoast, A., Treu, T., Brewer, B. J., Peterson, B. M., Barth, A. J., Malkan, M. A., De Rosa, G., Horne, Keith, Kriss, G. A., Arav, N., Bentz, M. C., Cackett, E. M., Bontà, E. Dalla, Dehghanian, M., Done, C., Ferland, G. J., Grier, C. J., Kaastra, J., Kara, E., Kochanek, C. S., Mathur, S., Mehdipour, M., Pogge, R. W., Proga, D., Vestergaard, M., Waters, T., Adams, S. M., Anderson, M. D., Arévalo, P., Beatty, T. G., Bennert, V. N., Bigley, A., Bisogni, S., Borman, G. A., Boroson, T. A., Bottorff, M. C., Brandt, W. N., Breeveld, A. A., Brotherton, M., Brown, J. E., Brown, J. S., Canalizo, G., Carini, M. T., Clubb, K. I., Comerford, J. M., Corsini, E. M., Crenshaw, D. M., Croft, S., Croxall, K. V., Deason, A. J., De Lorenzo-Cáceres, A., Denney, K. D., Dietrich, M., Edelson, R., Efimova, N. V., Ely, J., Evans, P. A., Fausnaugh, M. M., Filippenko, A. V., Flatland, K., Fox, O. D., Gardner, E., Gates, E. L., Gehrels, N., Geier, S., Gelbord, J. M., Gonzalez, L., Gorjian, V., Greene, J. E., Grupe, D., Gupta, A., Hall, P. B., Henderson, C. B., Hicks, S., Holmbeck, E., Holoien, T. W. -S., Hutchison, T., Im, M., Jensen, J. J., Johnson, C. A., Joner, M. D., Jones, J., Kaspi, S., Kelly, P. L., Kennea, J. A., Kim, M., Kim, S., Kim, S. C., King, A., Klimanov, S. A., Knigge, C., Krongold, Y., Lau, M. W., Lee, J. C., Leonard, D. C., Li, Miao, Lira, P., Lochhaas, C., Ma, Zhiyuan, Manne-Nicholas, E. R., MacInnis, F., Mauerhan, J. C., McGurk, R., Hardy, I. M. Mc, Montuori, C., Morelli, L., Mosquera, A., Mudd, D., Müller-Sánchez, F., Nazarov, S. V., Norris, R. P., Nousek, J. A., Nguyen, M. L., Ochner, P., Okhmat, D. N., Papadakis, I., Parks, J. R., Pei, L., Penny, M. T., Pizzella, A., Poleski, R., Pott, J. -U., Rafter, S. E., Rix, H. -W., Runnoe, J., Saylor, D. A., Schimoia, J. S., Scott, B., Sergeev, S. G., Shappee, B. J., Shivvers, I., Siegel, M., Simonian, G. V., Siviero, A., Skielboe, A., Somers, G., Spencer, M., Starkey, D., Stevens, D. J., Sung, H. -I., Tayar, J., Tejos, N., Turner, C. S., Uttley, P., Van Saders, J., Vaughan, S. A., Vican, L., Villanueva Jr., S., Villforth, C., Weiss, Y., Woo, J. -H., Yan, H., Young, S., Yuk, H., Zheng, W., Zhu, W., and Zu, Y.

Subjects
Astrophysics - Astrophysics of Galaxies
Abstract

We present geometric and dynamical modeling of the broad line region for the multi-wavelength reverberation mapping campaign focused on NGC 5548 in 2014. The dataset includes photometric and spectroscopic monitoring in the optical and ultraviolet, covering the H$\beta$, C IV, and Ly$\alpha$ broad emission lines. We find an extended disk-like H$\beta$ BLR with a mixture of near-circular and outflowing gas trajectories, while the C IV and Ly$\alpha$ BLRs are much less extended and resemble shell-like structures. There is clear radial structure in the BLR, with C IV and Ly$\alpha$ emission arising at smaller radii than the H$\beta$ emission. Using the three lines, we make three independent black hole mass measurements, all of which are consistent. Combining these results gives a joint inference of $\log_{10}(M_{\rm BH}/M_\odot) = 7.64^{+0.21}_{-0.18}$. We examine the effect of using the $V$ band instead of the UV continuum light curve on the results and find a size difference that is consistent with the measured UV-optical time lag, but the other structural and kinematic parameters remain unchanged, suggesting that the $V$ band is a suitable proxy for the ionizing continuum when exploring the BLR structure and kinematics. Finally, we compare the H$\beta$ results to similar models of data obtained in 2008 when the AGN was at a lower luminosity state. We find that the size of the emitting region increased during this time period, but the geometry and black hole mass remain unchanged, which confirms that the BLR kinematics suitably gauge the gravitational field of the central black hole., Comment: 26 pages, 19 figures, 1 table, accepted for publication in ApJ

Published
2020
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8. Neutron Star Extreme Matter Observatory: A kilohertz-band gravitational-wave detector in the global network

Author

Ackley, K., Adya, V. B., Agrawal, P., Altin, P., Ashton, G., Bailes, M., Baltinas, E., Barbuio, A., Beniwal, D., Blair, C., Blair, D., Bolingbroke, G. N., Bossilkov, V., Boublil, S. Shachar, Brown, D. D., Burridge, B. J., Bustillo, J. Calderon, Cameron, J., Cao, H. Tuong, Carlin, J. B., Chang, S., Charlton, P., Chatterjee, C., Chattopadhyay, D., Chen, X., Chi, J., Chow, J., Chu, Q., Ciobanu, A., Clarke, T., Clearwater, P., Cooke, J., Coward, D., Crisp, H., Dattatri, R. J., Deller, A. T., Dobie, D. A., Dunn, L., Easter, P. J., Eichholz, J., Evans, R., Flynn, C., Foran, G., Forsyth, P., Gai, Y., Galaudage, S., Galloway, D. K., Gendre, B., Goncharov, B., Goode, S., Gozzard, D., Grace, B., Graham, A. W., Heger, A., Vivanco, F. Hernandez, Hirai, R., Holland, N. A., Holmes, Z. J., Howard, E., Howell, E., Howitt, G., Hübner, M. T., Hurley, J., Ingram, C., Hamedan, V. Jaberian, Jenner, K., Ju, L., Kapasi, D. P., Kaur, T., Kijbunchoo, N., Kovalam, M., Choudhary, R. Kumar, Lasky, P. D., Lau, M. Y. M., Leung, J., Liu, J., Loh, K., Mailvagan, A., Mandel, I., McCann, J. J., McClelland, D. E., McKenzie, K., McManus, D., McRae, T., Melatos, A., Meyers, P., Middleton, H., Miles, M. T., Millhouse, M., Mong, Y. Lun, Mueller, B., Munch, J., Musiov, J., Muusse, S., Nathan, R. S., Naveh, Y., Neijssel, C., Neil, B., Ng, S. W. S., Oloworaran, V., Ottaway, D. J., Page, M., Pan, J., Pathak, M., Payne, E., Powell, J., Pritchard, J., Puckridge, E., Raidani, A., Rallabhandi, V., Reardon, D., Riley, J. A., Roberts, L., Romero-Shaw, I. M., Roocke, T. J., Rowell, G., Sahu, N., Sarin, N., Sarre, L., Sattari, H., Schiworski, M., Scott, S. M., Sengar, R., Shaddock, D., Shannon, R., SHI, J., Sibley, P., Slagmolen, B. J. J., Slaven-Blair, T., Smith, R. J. E., Spollard, J., Steed, L., Strang, L., Sun, H., Sunderland, A., Suvorova, S., Talbot, C., Thrane, E., Töyrä, D., Trahanas, P., Vajpeyi, A., van Heijningen, J. V., Vargas, A. F., Veitch, P. J., Vigna-Gomez, A., Wade, A., Walker, K., Wang, Z., Ward, R. L., Ward, K., Webb, S., Wen, L., Wette, K., Willcox, R., Winterflood, J., Wolf, C., Wu, B., Yap, M. Jet, You, Z., Yu, H., Zhang, J., Zhao, C., and Zhu, X.

Subjects
Astrophysics - High Energy Astrophysical Phenomena, Astrophysics - Instrumentation and Methods for Astrophysics, General Relativity and Quantum Cosmology
Abstract

Gravitational waves from coalescing neutron stars encode information about nuclear matter at extreme densities, inaccessible by laboratory experiments. The late inspiral is influenced by the presence of tides, which depend on the neutron star equation of state. Neutron star mergers are expected to often produce rapidly-rotating remnant neutron stars that emit gravitational waves. These will provide clues to the extremely hot post-merger environment. This signature of nuclear matter in gravitational waves contains most information in the 2-4 kHz frequency band, which is outside of the most sensitive band of current detectors. We present the design concept and science case for a neutron star extreme matter observatory (NEMO): a gravitational-wave interferometer optimized to study nuclear physics with merging neutron stars. The concept uses high circulating laser power, quantum squeezing and a detector topology specifically designed to achieve the high-frequency sensitivity necessary to probe nuclear matter using gravitational waves. Above one kHz, the proposed strain sensitivity is comparable to full third-generation detectors at a fraction of the cost. Such sensitivity changes expected event rates for detection of post-merger remnants from approximately one per few decades with two A+ detectors to a few per year, and potentially allows for the first gravitational-wave observations of supernovae, isolated neutron stars, and other exotica., Comment: Accepted for publication in PASA

Published
2020
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9. Space Telescope and Optical Reverberation Mapping Project. IX. Velocity-Delay Maps for Broad Emission Lines in NGC 5548

Author

Horne, Keith, De Rosa, G., Peterson, B. M., Barth, A. J., Ely, J., Fausnaugh, M. M., Kriss, G. A., Pei, L., Adams, S. M., Anderson, M. D., Arevalo, P., Beatty, T G., Bennert, V. N., Bentz, M. C., Bigley, A., Bisogni, S., Borman, G. A., Boroson, T. A., Bottorff, M. C., Brandt, W. N., Breeveld, A. A., Brotherton, M., Brown, J. E., Brown, J. S., Cackett, E. M., Canalizo, G., Carini, M. T., Clubb, K. I., Comerford, J. M., Corsini, E. M., Crenshaw, D. M., Croft, S., Croxall, K. V., Bonta, E. Dalla, Deason, A. J., Dehghanian, M., De Lorenzo-Caceres, A., Denney, K. D., Dietrich, M., Done, C., Edelson, R., Efimova, N. V., Eracleous, M., Evans, P. A., Ferland, G. J., Filippenko, A. V., Flatland, K., Fox, O. D., Gardner, E., Gates, E. L., Gehrels, N., Geier, S., Gelbord, J. M., Goad, M. R., Gonzalez, L., Gorjian, V., Greene, J. E., Grier, C. J., Grupe, D., Gupta, A., Hall, P. B., Henderson, C. B., Hicks, S., Holmbeck, E., Holoien, T. W. -S., Hutchison, T., Im, M., Jensen, J. J., Johnson, C. A., Joner, M. D., Jones, J., Kaastra, J., Kaspi, S., Kelly, P. L., Kennea, J. A., Kim, M., Kim, S., Kim, S. C., King, A., Klimanov, S. A., Kochanek, C. S., Korista, K. T., Krongold, Y., Lau, M. W., Lee, J. C., Leonard, D. C., Li, Miao, Lira, P., Lochhaas, C., Ma, Zhiyuan, MacInnis, F., Malkan, M. A., Manne-Nicholas, E. R., Mathur, S., Mauerhan, J. C., McGurk, R., Hardy, I. M. Mc, Montuori, C., Morelli, L., Mosquera, A., Mudd, D., Mueller-Sanchez, F., Nazarov, S. V., Netzer, H., Norris, R. P., Nousek, J. A., Nguyen, M. L., Ochner, P., Okhmat, D. N., Pancoast, A., Papadakis, I., Parks, J. R., Penny, M. T., Pizzella, A., Pogge, R. W., Poleski, R., Pott, J. -U., Proga, D., Rafter, S. E., Rix, H. -W., Runnoe, J., Saylor, D. A., Schimoia, J. S., Schnuelle, K., Scott, B., Sergeev, S. G., Shappee, B. J., Shivvers, I., Siegel, M., Simonian, G. V., Siviero, A., Skielboe, A., Somers, G., Spencer, M., Starkey, D., Stevens, D. J., Strauss, M. A., Sung, H. -I., Tayar, J., Teems, K. G., Tejos, N., Treu, T., Turner, C. S., Uttley, P., Van Saders, J ., Vestergaard, M., Vican, L., Villanueva Jr, S., Villforth, C., Weiss, Y., Woo, J. -H., Yan, H., Young, S., Yuk, H., Zakamska, N. L., Zheng, W., Zhu, W., and Zu, Y.

Subjects
Astrophysics - Astrophysics of Galaxies
Abstract

We report velocity-delay maps for prominent broad emission lines, Ly_alpha, CIV, HeII and H_beta, in the spectrum of NGC5548. The emission-line responses inhabit the interior of a virial envelope. The velocity-delay maps reveal stratified ionization structure. The HeII response inside 5-10 light-days has a broad single-peaked velocity profile. The Ly_alpha, CIV, and H_beta responses peak inside 10 light-days, extend outside 20 light-days, and exhibit a velocity profile with two peaks separated by 5000 km/s in the 10 to 20 light-day delay range. The velocity-delay maps show that the M-shaped lag vs velocity structure found in previous cross-correlation analysis is the signature of a Keplerian disk with a well-defined outer edge at R=20 light-days. The outer wings of the M arise from the virial envelope, and the U-shaped interior of the M is the lower half of an ellipse in the velocity-delay plane. The far-side response is weaker than that from the near side, so that we see clearly the lower half, but only faintly the upper half, of the velocity--delay ellipse. The delay tau=(R/c)(1-sin(i))=5 light-days at line center is from the near edge of the inclined ring, giving the inclination i=45 deg. A black hole mass of M=7x10^7 Msun is consistent with the velocity-delay structure. A barber-pole pattern with stripes moving from red to blue across the CIV and possibly Ly_alpha line profiles suggests the presence of azimuthal structure rotating around the far side of the broad-line region and may be the signature of precession or orbital motion of structures in the inner disk. Further HST observations of NGC 5548 over a multi-year timespan but with a cadence of perhaps 10 days rather than 1 day could help to clarify the nature of this new AGN phenomenon., Comment: 19 pages, 9 figures, ApJ in press

Published
2020
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11. Space Telescope and Optical Reverberation Mapping Project. VIII. Time Variability of Emission and Absorption in NGC 5548 Based on Modeling the Ultraviolet Spectrum

Author

Kriss, G. A., De Rosa, G., Ely, J., Peterson, B. M., Kaastra, J., Mehdipour, M., Ferland, G. J., Dehghanian, M., Mathur, S., Edelson, R., Korista, K. T., Arav, N., Barth, A. J., Bentz, M. C., Brandt, W. N., Crenshaw, D. M., Bontà, E. Dalla, Denney, K. D., Done, C., Eracleous, M., Fausnaugh, M. M., Gardner, E., Goad, M. R., Grier, C. J., Horne, Keith, Kochanek, C. S., Mchardy, I. M., Netzer, H., Pancoast, A., Pei, L., Pogge, R. W., Proga, D., Silva, C., Tejos, N., Vestergaard, M., Adams, S. M., Anderson, M. D., Arévalo, P., Beatty, T G., Behar, E., Bennert, V. N., Bianchi, S., Bigley, A., Bisogni, S., Boissay-Malaquin, R., Borman, G. A., Bottorff, M. C., Breeveld, A. A., Brotherton, M., Brown, J. E., Brown, J. S., Cackett, E. M., Canalizo, G., Cappi, M., Carini, M. T., Clubb, K. I., Comerford, J. M., Coker, C. T., Corsini, E. M., Costantini, E., Croft, S., Croxall, K. V., Deason, A. J., De Lorenzo-Cáceres, A., De Marco, B., Dietrich, M., Di Gesu, L., Ebrero, J., Evans, P. A., Filippenko, A. V., Flatland, K., Gates, E. L., Gehrels, N., Geier, Z S., Gelbord, J. M., Gonzalez, L., Gorjian, V., Grupe, D., Gupta, A., Hall, P. B., Henderson, C. B., Hicks, S., Holmbeck, E., Holoien, T. W. -S., Hutchison, T. A., Im, M., Jensen, J. J., Johnson, C. A., Joner, M. D., Kaspi, S., Kelly, B. C., Kelly, P. L., Kennea, J. A., Kim, M., Kim, S. C., Kim, S. Y., King, A., Klimanov, S. A., Krongold, Y., Lau, M. W., Lee, J. C., Leonard, D. C., Li, Miao, Lira, P., Lochhaas, C., Ma, Zhiyuan, Macinnis, F., Malkan, M. A., Manne-Nicholas, E. R., Matt, G., Mauerhan, J. C., Mcgurk, R., Montuori, C., Morelli, L., Mosquera, A., Mudd, D., Müller-Sánchez, F., Nazarov, S. V., Norris, R. P., Nousek, J. A., Nguyen, M. L., Ochner, P., Okhmat, D. N., Paltani, S., Parks, J. R., Pinto, C., Pizzella, A., Poleski, R., Ponti, G., Pott, J. -U., Rafter, S. E., Rix, H. -W., Runnoe, J., Saylor, D. A., Schimoia, J. S., Schnülle, K., Scott, B., Sergeev, S. G., Shappee, B. J., Shivvers, I., Siegel, M., Simonian, G. V., Siviero, A., Skielboe, A., Somers, G., Spencer, M., Starkey, D., Stevens, D. J., Sung, H. -I., Tayar, J., Teems, K. G., Treu, T., Turner, C. S., Uttley, P., Van Saders, J ., Vican, L., Villforth, C., Villanueva Jr., S., Walton, D. J., Waters, T., Weiss, Y., Woo, J. -H., Yan, H., Yuk, H., Zheng, W., Zhu, W., and Zu, Y.

Subjects
Astrophysics - Astrophysics of Galaxies
Abstract

We model the ultraviolet spectra of the Seyfert 1 galaxy NGC~5548 obtained with the Hubble Space Telescope during the 6-month reverberation-mapping campaign in 2014. Our model of the emission from NGC 5548 corrects for overlying absorption and deblends the individual emission lines. Using the modeled spectra, we measure the response to continuum variations for the deblended and absorption-corrected individual broad emission lines, the velocity-dependent profiles of Ly$\alpha$ and C IV, and the narrow and broad intrinsic absorption features. We find that the time lags for the corrected emission lines are comparable to those for the original data. The velocity-binned lag profiles of Ly$\alpha$ and C IV have a double-peaked structure indicative of a truncated Keplerian disk. The narrow absorption lines show delayed response to continuum variations corresponding to recombination in gas with a density of $\sim 10^5~\rm cm^{-3}$. The high-ionization narrow absorption lines decorrelate from continuum variations during the same period as the broad emission lines. Analyzing the response of these absorption lines during this period shows that the ionizing flux is diminished in strength relative to the far-ultraviolet continuum. The broad absorption lines associated with the X-ray obscurer decrease in strength during this same time interval. The appearance of X-ray obscuration in $\sim\,2012$ corresponds with an increase in the luminosity of NGC 5548 following an extended low state. We suggest that the obscurer is a disk wind triggered by the brightening of NGC 5548 following the decrease in size of the broad-line region during the preceding low-luminosity state., Comment: 50 pages, 30 figures, uses aastex62.cls. Accepted for publication in ApJ, 07/06/2019. High-level products page in MAST will go live after 7/15/2019. Replaced Figure 4 on 7/12/2019 to be more red/green color-blind friendly

Published
2019
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14. Space Telescope and Optical Reverberation Mapping Project. VII. Understanding the UV anomaly in NGC 5548 with X-Ray Spectroscopy

Author

Mathur, S., Gupta, A., Page, K., Pogge, R. W., Krongold, Y., Goad, M. R., Adams, S. M., Anderson, M. D., Arevalo, P., Barth, A. J., Bazhaw, C., Beatty, T. G., Bentz, M. C., Bigley, A., Bisogni, S., Borman, G. A., Boroson, T. A., Bottorff, M. C., Brandt, W. N., Breeveld, A. A., Brown, J. E., Brown, J. S., Cackett, E. M., Canalizo, G., Carini, M. T., Clubb, K. I., Comerford, J. M., Coker, C. T., Corsini, E. M., Crenshaw, D. M., Croft, S., Croxall, K. V., Bonta, E. Dalla, Deason, A. J., Denney, K. D., De Lorenzo-Caceres, A., De Rosa, G., Dietrich, M., Edelson, R., Ely, J., Eracleous, M., Evans, P. A., Fausnaugh, M. M., Ferland, G. J., Filippenko, A. V., Flatland, K., Fox, O. D., Gates, E. L., Gehrels, N., Geier, S., Gelbord, J. M., Gorjian, V., Greene, J. E., Grier, C. J., Grupe, D., Hall, P. B., Henderson, C. B., Hicks, S., Holmbeck, E., Holoien, T. W. -S., Horenstein, D., Horne, Keith, Hutchison, T., Im, M., Jensen, J. J., Johnson, C. A., Joner, M. D., Jones, J., Kaastra, J., Kaspi, S., Kelly, B. C., Kelly, P. L., Kennea, J. A., Kim, M., Kim, S., Kim, S. C., King, A., Klimanov, S. A., Kochanek, C. S., Korista, K. T., Kriss, G. A., Lau, M. W., Lee, J. C., Leonard, D. C., Li, M., Lira, P., Ma, Z., MacInnis, F., Manne-Nicholas, E. R., Malkan, M. A., Mauerhan, J. C., McGurk, R., McHardy, I. M., Montouri, C., Morelli, L., Mosquera, A., Mudd, D., Muller-Sanchez, F., Musso, R., Nazarov, S. V., Netzer, H., Nguyen, M. L., Norris, R. P., Nousek, J. A., Ochner, P., Okhmat, D. N., Ou-Yang, B., Pancoast, A., Papadakis, I., Parks, J. R., Pei, L., Peterson, B. M., Pizzella, A., Poleski, R., Pott, J. -U., Rafter, S. E., Rix, H. -W., Runnoe, J., Saylor, D. A., Schimoia, J. S., Schnülle, K., Sergeev, S. G., Shappee, B. J., Shivvers, I., Siegel, M., Simonian, G. V., Siviero, A., Skielboe, A., Somers, G., Spencer, M., Starkey, D., Stevens, D. J., Sung, H. -I., Tayar, J., Tejos, N., Turner, C. S., Uttley, P., Van Saders, J., Vestergaard, M., Vican, L., VillanuevaJr., S., Villforth, C., Weiss, Y., Woo, J. -H., Yan, H., Young, S., Yuk, H., Zheng, W., Zhu, W., and Zu, Y.

Subjects
Astrophysics - Astrophysics of Galaxies
Abstract

During the Space Telescope and Optical Reverberation Mapping Project (STORM) observations of NGC 5548, the continuum and emission-line variability became de-correlated during the second half of the 6-month long observing campaign. Here we present Swift and Chandra X-ray spectra of NGC 5548 obtained as a part of the campaign. The Swift spectra show that excess flux (relative to a power-law continuum) in the soft X-ray band appears before the start of the anomalous emission-line behavior, peaks during the period of the anomaly, and then declines. This is a model-independent result suggesting that the soft excess is related to the anomaly. We divide the Swift data into on- and off-anomaly spectra to characterize the soft excess via spectral fitting. The cause of the spectral differences is likely due to a change in the intrinsic spectrum rather than being due to variable obscuration or partial covering. The Chandra spectra have lower signal-to-noise ratios, but are consistent with Swift data. Our preferred model of the soft excess is emission from an optically thick, warm Comptonizing corona, the effective optical depth of which increases during the anomaly. This model simultaneously explains all the three observations: the UV emission line flux decrease, the soft-excess increase, and the emission line anomaly., Comment: ApJ in press. Replaced with the accepted version

Published
2017
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15. Space Telescope and Optical Reverberation Mapping Project. V. Optical Spectroscopic Campaign and Emission-Line Analysis for NGC 5548

Author

Pei, L., Fausnaugh, M. M., Barth, A. J., Peterson, B. M., Bentz, M. C., De Rosa, G., Denney, K. D., Goad, M. R., Kochanek, C. S., Korista, K. T., Kriss, G. A., Pogge, R. W., Bennert, V. N., Brotherton, M., Clubb, K. I., Bontà, E. Dalla, Filippenko, A. V., Greene, J. E., Grier, C. J., Vestergaard, M., Zheng, W., Adams, Scott M., Beatty, Thomas G., Bigley, A., Brown, Jacob E., Brown, Jonathan S., Canalizo, G., Comerford, J. M., Coker, Carl T., Corsini, E. M., Croft, S., Croxall, K. V., Deason, A. J., Eracleous, Michael, Fox, O. D., Gates, E. L., Henderson, C. B., Holmbeck, E., Holoien, T. W. -S., Jensen, J. J., Johnson, C. A., Kelly, P. L., Kim, S., King, A., Lau, M. W., Li, Miao, Lochhaas, Cassandra, Ma, Zhiyuan, Manne-Nicholas, E. R., Mauerhan, J. C., Malkan, M. A., McGurk, R., Morelli, L., Mosquera, Ana, Mudd, Dale, Sanchez, F. Muller, Nguyen, M. L., Ochner, P., Ou-Yang, B., Pancoast, A., Penny, Matthew T., Pizzella, A., Poleski, Radosław, Runnoe, Jessie, Scott, B., Schimoia, Jaderson S., Shappee, B. J., Shivvers, I., Simonian, Gregory V., Siviero, A., Somers, Garrett, Stevens, Daniel J., Strauss, M. A., Tayar, Jamie, Tejos, N., Treu, T., Van Saders, J., Vican, L., Villanueva Jr., S., Yuk, H., Zakamska, N. L., Zhu, W., Anderson, M. D., Arévalo, P., Bazhaw, C., Bisogni, S., Borman, G. A., Bottorff, M. C., Brandt, W. N., Breeveld, A. A., Cackett, E. M., Carini, M. T., Crenshaw, D. M., De Lorenzo-Cáceres, A., Dietrich, M., Edelson, R., Efimova, N. V., Ely, J., Evans, P. A., Ferland, G. J., Flatland, K., Gehrels, N., Geier, S., Gelbord, J. M., Grupe, D., Gupta, A., Hall, P. B., Hicks, S., Horenstein, D., Horne, Keith, Hutchison, T., Im, M., Joner, M. D., Jones, J., Kaastra, J., Kaspi, S., Kelly, B. C., Kennea, J. A., Kim, M., Kim, S. C., Klimanov, S. A., Lee, J. C., Leonard, D. C., Lira, P., MacInnis, F., Mathur, S., McHardy, I. M., Montouri, C., Musso, R., Nazarov, S. V., Netzer, H., Norris, R. P., Nousek, J. A., Okhmat, D. N., Papadakis, I., Parks, J. R., Pott, J. -U., Rafter, S. E., Rix, H. -W., Saylor, D. A., Schnülle, K., Sergeev, S. G., Siegel, M., Skielboe, A., Spencer, M., Starkey, D., Sung, H. -I., Teems, K. G., Turner, C. S., Uttley, P., Villforth, C., Weiss, Y., Woo, J. -H., Yan, H., Young, S., and Zu, Y.

Subjects
Astrophysics - Astrophysics of Galaxies
Abstract

We present the results of an optical spectroscopic monitoring program targeting NGC 5548 as part of a larger multi-wavelength reverberation mapping campaign. The campaign spanned six months and achieved an almost daily cadence with observations from five ground-based telescopes. The H$\beta$ and He II $\lambda$4686 broad emission-line light curves lag that of the 5100 $\AA$ optical continuum by $4.17^{+0.36}_{-0.36}$ days and $0.79^{+0.35}_{-0.34}$ days, respectively. The H$\beta$ lag relative to the 1158 $\AA$ ultraviolet continuum light curve measured by the Hubble Space Telescope is roughly $\sim$50% longer than that measured against the optical continuum, and the lag difference is consistent with the observed lag between the optical and ultraviolet continua. This suggests that the characteristic radius of the broad-line region is $\sim$50% larger than the value inferred from optical data alone. We also measured velocity-resolved emission-line lags for H$\beta$ and found a complex velocity-lag structure with shorter lags in the line wings, indicative of a broad-line region dominated by Keplerian motion. The responses of both the H$\beta$ and He II $\lambda$4686 emission lines to the driving continuum changed significantly halfway through the campaign, a phenomenon also observed for C IV, Ly $\alpha$, He II(+O III]), and Si IV(+O IV]) during the same monitoring period. Finally, given the optical luminosity of NGC 5548 during our campaign, the measured H$\beta$ lag is a factor of five shorter than the expected value implied by the $R_\mathrm{BLR} - L_\mathrm{AGN}$ relation based on the past behavior of NGC 5548., Comment: 22 pages, 13 figures, accepted to ApJ

Published
2017
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17. Formative Study on the Wearability and Usability of a Large-Volume Patch Injector

Author

Lange J, Schneider A, Jordi C, Lau M, and Disher T

Subjects
self-medication, subcutaneous injection, large-volume injection, bolus dose, drug delivery, usability, medical devices, Medical technology, R855-855.5
Abstract

Jakob Lange,1 Andreas Schneider,1 Christoph Jordi,1 Michael Lau,2 Timothy Disher2 1Ypsomed Delivery Systems, Ypsomed AG, Burgdorf, Switzerland; 2Insight Product Development, Chicago, IL, USACorrespondence: Jakob LangeYpsomed AG, Brunnmattstrasse 06, Burgdorf, 3401, SwitzerlandTel +41 34 424 31 87Email jakob.lange@ypsomed.comBackground: The subcutaneous self-administration of biologics using a single large-volume bolus dose requires novel large-volume patch injectors. However, the usability and wearability of such on-body devices has rarely been investigated thus far. Therefore, this formative simulated use experiment studies the overall handling and acceptability in terms of the size and weight of a novel 10 mL large-volume patch injector device platform.Methods: Twenty-three participants, including patients and healthcare professionals, simulated two injections with the large-volume patch injector, each lasting 17 min. During the injections, the patient participants performed predefined movements and activities with the on-body devices. Perceived usability and wearability were assessed through observation by the moderator and participant-reported feedback using five-point Likert scales and open-ended interviews.Results: All participants successfully completed the simulated injections. Only non-serious usability issues were identified. Users rated the device acceptability in terms of wearability and usability with high ratings.Conclusion: The results suggest the safe and effective usage of a novel prefilled large-volume patch injector that enables the subcutaneous delivery of a single bolus dose of up to 10 mL with an injection duration of 15 min. The participants of the simulated use study successfully used the device regardless of the disease state, age, or body size and habitus.Keywords: self-medication, subcutaneous injection, large-volume injection, bolus dose, drug delivery, usability, medical devices

Published
2021

24. Long-term impacts of egg quiescence and Wolbachia infection on lipid profiles in Aedes aegypti: Ovarian roles in lipid synthesis during reproduction

Author

Lau, M-J, Nie, S, Ross, PA, Endersby-Harshman, NM, Hoffmann, AA, Lau, M-J, Nie, S, Ross, PA, Endersby-Harshman, NM, and Hoffmann, AA

Abstract

Wolbachia, an endosymbiotic bacterium, relies on nutrients from its host to complete its life cycle. The presence of Wolbachia strain wAlbB in the mosquito Aedes aegypti during egg or larval stages affects the host's development, leading to the absence of developed and visible ovaries in adult mosquito females. In this study, we investigated the impacts of egg quiescence and Wolbachia infection on lipid profiles of adult Ae. aegypti females, and discerned the role of ovaries in lipid synthesis in the reproductive process. The lipidomes of Wolbachia infected and uninfected female individuals at various developmental stages were quantitatively analyzed by LC-MS/MS. Lipidomic change patterns were systematically further investigated in wAlbB-infected fertile females and infertile females following blood feeding. Prolonged egg quiescence induced a shortage of acyl-carnitine (CAR) and potentially impacted some molecules of diacyl-phospholipid (diacyl-PL) and sphingolipid (SL) in young adult mosquitoes. After the first gonotrophic cycle, infertile females accumulated more CAR and lyso-phospholipid (lyso-PL) than fertile females. Then in the second gonotrophic cycle, the patterns of different lipid groups remained similar between fertile and infertile females. Only a small proportion of molecules of triglyceride (TG), phospholipid (lyso-PL and diacyl-PL) and ceramide (Cer) increased exclusively in fertile females from 0 h to 16 h post blood meal, suggesting that the generation or prescence of these lipids rely on ovaries. In addition, we found cardiolipins (CL) might be impacted by Wolbachia infection at the egg stage, and infected mosquitoes also showed distinct patterns between fertile and infertile females at their second gonotrophic cycle. Our study provides new insights into the long-term influence of Wolbachia on lipid profiles throughout various life stages of mosquitoes. Additionally, it suggests a role played by ovaries in lipid synthesis during mosquito reproducti

Published
2024

25. The effect of repeat feeding on dengue virus transmission potential in Wolbachia-infected Aedes aegypti following extended egg quiescence

Author

Voronin, D, Lau, M-J, Valdez, AR, Jones, MJ, Aranson, I, Hoffmann, AA, McGraw, EA, Voronin, D, Lau, M-J, Valdez, AR, Jones, MJ, Aranson, I, Hoffmann, AA, and McGraw, EA

Abstract

As Wolbachia pipientis is more widely being released into field populations of Aedes aegypti for disease control, the ability to select the appropriate strain for differing environments is increasingly important. A previous study revealed that longer-term quiescence in the egg phase reduced the fertility of mosquitoes, especially those harboring the wAlbB Wolbachia strain. This infertility was also associated with a greater biting rate. Here, we attempt to quantify the effect of this heightened biting behavior on the transmission potential of the dengue virus using a combination of assays for fitness, probing behavior, and vector competence, allowing repeat feeding, and incorporate these effects in a model of R0. We show that Wolbachia-infected infertile mosquitoes are more interested in feeding almost immediately after an initial blood meal relative to wild type and Wolbachia-infected fertile mosquitoes and that these differences continue for up to 8 days over the period we measured. As a result, the infertile Wolbachia mosquitoes have higher virus prevalence and loads than Wolbachia-fertile mosquitoes. We saw limited evidence of Wolbachia-mediated blocking in the disseminated tissue (legs) in terms of prevalence but did see reduced viral loads. Using a previously published estimate of the extrinsic incubation period, we demonstrate that the effect of repeat feeding/infertility is insufficient to overcome the effects of Wolbachia-mediated blocking on R0. These estimates are very conservative, however, and we posit that future studies should empirically measure EIP under a repeat feeding model. Our findings echo previous work where periods of extensive egg quiescence affected the reproductive success of Wolbachia-infected Ae. aegypti. Additionally, we show that increased biting behavior in association with this infertility in Wolbachia-infected mosquitoes may drive greater vector competence. These relationships require further exploration, given their ability to aff

Published
2024

27. Astrophysics with the Laser Interferometer Space Antenna

Author

Amaro-Seoane, P, Andrews, J, Arca Sedda, M, Askar, A, Baghi, Q, Balasov, R, Bartos, I, Bavera, S, Bellovary, J, Berry, C, Berti, E, Bianchi, S, Blecha, L, Blondin, S, Bogdanović, T, Boissier, S, Bonetti, M, Bonoli, S, Bortolas, E, Breivik, K, Capelo, P, Caramete, L, Cattorini, F, Charisi, M, Chaty, S, Chen, X, Chruślińska, M, Chua, A, Church, R, Colpi, M, D’Orazio, D, Danielski, C, Davies, M, Dayal, P, De Rosa, A, Derdzinski, A, Destounis, K, Dotti, M, Duţan, I, Dvorkin, I, Fabj, G, Foglizzo, T, Ford, S, Fouvry, J, Franchini, A, Fragos, T, Fryer, C, Gaspari, M, Gerosa, D, Graziani, L, Groot, P, Habouzit, M, Haggard, D, Haiman, Z, Han, W, Istrate, A, Johansson, P, Khan, F, Kimpson, T, Kokkotas, K, Kong, A, Korol, V, Kremer, K, Kupfer, T, Lamberts, A, Larson, S, Lau, M, Liu, D, Lloyd-Ronning, N, Lodato, G, Lupi, A, Ma, C, Maccarone, T, Mandel, I, Mangiagli, A, Mapelli, M, Mathis, S, Mayer, L, Mcgee, S, Mckernan, B, Miller, M, Mota, D, Mumpower, M, Nasim, S, Nelemans, G, Noble, S, Pacucci, F, Panessa, F, Paschalidis, V, Pfister, H, Porquet, D, Quenby, J, Ricarte, A, Röpke, F, Regan, J, Rosswog, S, Ruiter, A, Ruiz, M, Runnoe, J, Schneider, R, Amaro-Seoane P., Andrews J., Arca Sedda M., Askar A., Baghi Q., Balasov R., Bartos I., Bavera S. S., Bellovary J., Berry C. P. L., Berti E., Bianchi S., Blecha L., Blondin S., Bogdanović T., Boissier S., Bonetti M., Bonoli S., Bortolas E., Breivik K., Capelo P. R., Caramete L., Cattorini F., Charisi M., Chaty S., Chen X., Chruślińska M., Chua A. J. K., Church R., Colpi M., D’Orazio D., Danielski C., Davies M. B., Dayal P., De Rosa A., Derdzinski A., Destounis K., Dotti M., Duţan I., Dvorkin I., Fabj G., Foglizzo T., Ford S., Fouvry J. B., Franchini A., Fragos T., Fryer C., Gaspari M., Gerosa D., Graziani L., Groot P., Habouzit M., Haggard D., Haiman Z., Han W. B., Istrate A., Johansson P. H., Khan F. M., Kimpson T., Kokkotas K., Kong A., Korol V., Kremer K., Kupfer T., Lamberts A., Larson S., Lau M., Liu D., Lloyd-Ronning N., Lodato G., Lupi A., Ma C. P., Maccarone T., Mandel I., Mangiagli A., Mapelli M., Mathis S., Mayer L., McGee S., McKernan B., Miller M. C., Mota D. F., Mumpower M., Nasim S. S., Nelemans G., Noble S., Pacucci F., Panessa F., Paschalidis V., Pfister H., Porquet D., Quenby J., Ricarte A., Röpke F. K., Regan J., Rosswog S., Ruiter A., Ruiz M., Runnoe J., Schneider R., Amaro-Seoane, P, Andrews, J, Arca Sedda, M, Askar, A, Baghi, Q, Balasov, R, Bartos, I, Bavera, S, Bellovary, J, Berry, C, Berti, E, Bianchi, S, Blecha, L, Blondin, S, Bogdanović, T, Boissier, S, Bonetti, M, Bonoli, S, Bortolas, E, Breivik, K, Capelo, P, Caramete, L, Cattorini, F, Charisi, M, Chaty, S, Chen, X, Chruślińska, M, Chua, A, Church, R, Colpi, M, D’Orazio, D, Danielski, C, Davies, M, Dayal, P, De Rosa, A, Derdzinski, A, Destounis, K, Dotti, M, Duţan, I, Dvorkin, I, Fabj, G, Foglizzo, T, Ford, S, Fouvry, J, Franchini, A, Fragos, T, Fryer, C, Gaspari, M, Gerosa, D, Graziani, L, Groot, P, Habouzit, M, Haggard, D, Haiman, Z, Han, W, Istrate, A, Johansson, P, Khan, F, Kimpson, T, Kokkotas, K, Kong, A, Korol, V, Kremer, K, Kupfer, T, Lamberts, A, Larson, S, Lau, M, Liu, D, Lloyd-Ronning, N, Lodato, G, Lupi, A, Ma, C, Maccarone, T, Mandel, I, Mangiagli, A, Mapelli, M, Mathis, S, Mayer, L, Mcgee, S, Mckernan, B, Miller, M, Mota, D, Mumpower, M, Nasim, S, Nelemans, G, Noble, S, Pacucci, F, Panessa, F, Paschalidis, V, Pfister, H, Porquet, D, Quenby, J, Ricarte, A, Röpke, F, Regan, J, Rosswog, S, Ruiter, A, Ruiz, M, Runnoe, J, Schneider, R, Amaro-Seoane P., Andrews J., Arca Sedda M., Askar A., Baghi Q., Balasov R., Bartos I., Bavera S. S., Bellovary J., Berry C. P. L., Berti E., Bianchi S., Blecha L., Blondin S., Bogdanović T., Boissier S., Bonetti M., Bonoli S., Bortolas E., Breivik K., Capelo P. R., Caramete L., Cattorini F., Charisi M., Chaty S., Chen X., Chruślińska M., Chua A. J. K., Church R., Colpi M., D’Orazio D., Danielski C., Davies M. B., Dayal P., De Rosa A., Derdzinski A., Destounis K., Dotti M., Duţan I., Dvorkin I., Fabj G., Foglizzo T., Ford S., Fouvry J. B., Franchini A., Fragos T., Fryer C., Gaspari M., Gerosa D., Graziani L., Groot P., Habouzit M., Haggard D., Haiman Z., Han W. B., Istrate A., Johansson P. H., Khan F. M., Kimpson T., Kokkotas K., Kong A., Korol V., Kremer K., Kupfer T., Lamberts A., Larson S., Lau M., Liu D., Lloyd-Ronning N., Lodato G., Lupi A., Ma C. P., Maccarone T., Mandel I., Mangiagli A., Mapelli M., Mathis S., Mayer L., McGee S., McKernan B., Miller M. C., Mota D. F., Mumpower M., Nasim S. S., Nelemans G., Noble S., Pacucci F., Panessa F., Paschalidis V., Pfister H., Porquet D., Quenby J., Ricarte A., Röpke F. K., Regan J., Rosswog S., Ruiter A., Ruiz M., Runnoe J., and Schneider R.

Abstract

The Laser Interferometer Space Antenna (LISA) will be a transformative experiment for gravitational wave astronomy, and, as such, it will offer unique opportunities to address many key astrophysical questions in a completely novel way. The synergy with ground-based and space-born instruments in the electromagnetic domain, by enabling multi-messenger observations, will add further to the discovery potential of LISA. The next decade is crucial to prepare the astrophysical community for LISA’s first observations. This review outlines the extensive landscape of astrophysical theory, numerical simulations, and astronomical observations that are instrumental for modeling and interpreting the upcoming LISA datastream. To this aim, the current knowledge in three main source classes for LISA is reviewed; ultra-compact stellar-mass binaries, massive black hole binaries, and extreme or interme-diate mass ratio inspirals. The relevant astrophysical processes and the established modeling techniques are summarized. Likewise, open issues and gaps in our understanding of these sources are highlighted, along with an indication of how LISA could help making progress in the different areas. New research avenues that LISA itself, or its joint exploitation with upcoming studies in the electromagnetic domain, will enable, are also illustrated. Improvements in modeling and analysis approaches, such as the combination of numerical simulations and modern data science techniques, are discussed. This review is intended to be a starting point for using LISA as a new discovery tool for understanding our Universe.

Published
2023

32. Gas permeation rates of ultrathin graphite sealed SiO2 cavities.

Author

Liu, Yan-Xin, Ambjørner, Hjalte Rørbech, Bonczyk, Tobias G., Dollekamp, Edwin, Kaas, Lau M., and Vesborg, Peter C. K.

Subjects
MOLECULAR sieves, GRAPHENE, GASES
Abstract

Despite the proven impermeability of graphene toward most standard gases, graphene/graphite sealed SiO2 cavities always exhibit a nonzero leak rate, and the physical leakage mechanism is still unclear. By measuring leak rates of different gases for the same cavities sealed by ultrathin graphite under identical conditions, we find that the leak rates generally depend on the kinetic diameter of the gas molecules, which implies that the leakage is caused by a molecular sieving mechanism. By comparing different samples, we find that the leak rate of any gas in a particular sample is well predicted by the leak rate of N2 in that sample. In addition, we observe enhanced leak rates of water-soluble molecules. We infer that the leakage path (i.e., the graphene/graphite–SiO2 interface) favors hydrophilic species. [ABSTRACT FROM AUTHOR]

Published
2022
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33. The Influence of Form- and Meaning-Based Predictions on Cortical Speech Processing Under Challenging Listening Conditions: A MEG Study

Author

Carine Signoret, Lau M. Andersen, Örjan Dahlström, Rina Blomberg, Daniel Lundqvist, Mary Rudner, and Jerker Rönnberg

Subjects
speech perception, MEG, predictability, working memory, semantic knowledge, phonological knowledge, Neurosciences. Biological psychiatry. Neuropsychiatry, RC321-571
Abstract

Under adverse listening conditions, prior linguistic knowledge about the form (i.e., phonology) and meaning (i.e., semantics) help us to predict what an interlocutor is about to say. Previous research has shown that accurate predictions of incoming speech increase speech intelligibility, and that semantic predictions enhance the perceptual clarity of degraded speech even when exact phonological predictions are possible. In addition, working memory (WM) is thought to have specific influence over anticipatory mechanisms by actively maintaining and updating the relevance of predicted vs. unpredicted speech inputs. However, the relative impact on speech processing of deviations from expectations related to form and meaning is incompletely understood. Here, we use MEG to investigate the cortical temporal processing of deviations from the expected form and meaning of final words during sentence processing. Our overall aim was to observe how deviations from the expected form and meaning modulate cortical speech processing under adverse listening conditions and investigate the degree to which this is associated with WM capacity. Results indicated that different types of deviations are processed differently in the auditory N400 and Mismatch Negativity (MMN) components. In particular, MMN was sensitive to the type of deviation (form or meaning) whereas the N400 was sensitive to the magnitude of the deviation rather than its type. WM capacity was associated with the ability to process phonological incoming information and semantic integration.

Published
2020
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34. Attentional modulation of the auditory steady-state response across the cortex

Author

Cassia Low Manting, Lau M. Andersen, Balazs Gulyas, Fredrik Ullén, and Daniel Lundqvist

Subjects
ASSR, Frequency-tagging, Selective auditory attention, Amplitude-modulation, Diotic, Music, Neurosciences. Biological psychiatry. Neuropsychiatry, RC321-571
Abstract

Selective auditory attention allows us to focus on relevant sounds within noisy or complex auditory environments, and is essential for the processing of speech and music. The auditory steady-state response (ASSR) has been proposed as a neural measure for tracking selective auditory attention, even within continuous and complex soundscapes. However, the current literature is inconsistent on how the ASSR is influenced by selective attention, with findings based primarily on attention being directed to either ear rather than to sound content. In this experiment, a mixture of melody streams was presented to both ears identically (diotically) as we examined if selective auditory attention to sound content influences the ASSR. Using magnetoencephalography (MEG), we assessed the stream-specific ASSRs from three frequency-tagged melody streams when attention was directed between each melody stream, based on their respective pitch and timing. Our main results showed that selective attention enhances the ASSR power of an attended melody stream by 14% at a general sensor level. This ability to readily capture attentional changes in a stimuli-precise manner makes the ASSR a useful tool for studying selective auditory attention, especially in complex auditory environments. As a secondary aim, we explored the distribution of cortical ASSR sources and their respective attentional modulation using a distributed source model of the ASSR activity. Notably, we uncovered the existence of ASSR attentional modulation outside the temporal cortices. Across-subject averages of the attentional enhancement over the cortical surface suggest that frontal regions show up to ~80% enhancement, while temporal and parietal cortices were enhanced by 20–25%. Importantly, this work advocates a novel ‘beyond the temporal cortex’ perspective on ASSR modulation and also serves as a template for future studies to precisely pin-point which cortical sites are more susceptible to ASSR attentional modulation.

Published
2020
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35. Can EEG and MEG detect signals from the human cerebellum?

Author

Lau M. Andersen, Karim Jerbi, and Sarang S. Dalal

Subjects
Neurosciences. Biological psychiatry. Neuropsychiatry, RC321-571
Abstract

The cerebellum plays a key role in the regulation of motor learning, coordination and timing, and has been implicated in sensory and cognitive processes as well. However, our current knowledge of its electrophysiological mechanisms comes primarily from direct recordings in animals, as investigations into cerebellar function in humans have instead predominantly relied on lesion, haemodynamic and metabolic imaging studies. While the latter provide fundamental insights into the contribution of the cerebellum to various cerebellar-cortical pathways mediating behaviour, they remain limited in terms of temporal and spectral resolution. In principle, this shortcoming could be overcome by monitoring the cerebellum’s electrophysiological signals. Non-invasive assessment of cerebellar electrophysiology in humans, however, is hampered by the limited spatial resolution of electroencephalography (EEG) and magnetoencephalography (MEG) in subcortical structures, i.e., deep sources. Furthermore, it has been argued that the anatomical configuration of the cerebellum leads to signal cancellation in MEG and EEG. Yet, claims that MEG and EEG are unable to detect cerebellar activity have been challenged by an increasing number of studies over the last decade. Here we address this controversy and survey reports in which electrophysiological signals were successfully recorded from the human cerebellum. We argue that the detection of cerebellum activity non-invasively with MEG and EEG is indeed possible and can be enhanced with appropriate methods, in particular using connectivity analysis in source space. We provide illustrative examples of cerebellar activity detected with MEG and EEG. Furthermore, we propose practical guidelines to optimize the detection of cerebellar activity with MEG and EEG. Finally, we discuss MEG and EEG signal contamination that may lead to localizing spurious sources in the cerebellum and suggest ways of handling such artefacts.This review is to be read as a perspective review that highlights that it is indeed possible to measure cerebellum with MEG and EEG and encourages MEG and EEG researchers to do so. Its added value beyond highlighting and encouraging is that it offers useful advice for researchers aspiring to investigate the cerebellum with MEG and EEG.

Published
2020
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36. On-scalp MEG sensor localization using magnetic dipole-like coils: A method for highly accurate co-registration

Author

Christoph Pfeiffer, Silvia Ruffieux, Lau M. Andersen, Alexei Kalabukhov, Dag Winkler, Robert Oostenveld, Daniel Lundqvist, and Justin F. Schneiderman

Subjects
Magnetoencephalography (MEG), On-scalp MEG, Co-registration, Sensor localization, Magnetic dipole, Coil, Neurosciences. Biological psychiatry. Neuropsychiatry, RC321-571
Abstract

Source modelling in magnetoencephalography (MEG) requires precise co-registration of the sensor array and the anatomical structure of the measured individual’s head. In conventional MEG, the positions and orientations of the sensors relative to each other are fixed and known beforehand, requiring only localization of the head relative to the sensor array. Since the sensors in on-scalp MEG are positioned on the scalp, locations of the individual sensors depend on the subject’s head shape and size. The positions and orientations of on-scalp sensors must therefore be measured at every recording. This can be achieved by inverting conventional head localization, localizing the sensors relative to the head - rather than the other way around.In this study we present a practical method for localizing sensors using magnetic dipole-like coils attached to the subject’s head. We implement and evaluate the method in a set of on-scalp MEG recordings using a 7-channel on-scalp MEG system based on high critical temperature superconducting quantum interference devices (high-Tc SQUIDs). The method allows individually localizing the sensor positions, orientations, and responsivities with high accuracy using only a short averaging time (≤ 2 ​mm, < 3° and < 3%, respectively, with 1-s averaging), enabling continuous sensor localization. Calibrating and jointly localizing the sensor array can further improve the accuracy of position and orientation (< 1 ​mm and < 1°, respectively, with 1-s coil recordings).We demonstrate source localization of on-scalp recorded somatosensory evoked activity based on co-registration with our method. Equivalent current dipole fits of the evoked responses corresponded well (within 4.2 ​mm) with those based on a commercial, whole-head MEG system.

Published
2020
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41. Active vibration control at machinery feet

Author

Lau, M. W. S.

Subjects
624.1, Mechanical Engineering
Abstract

The unmitigated transmission of undesirable vibration can result in problems by way of causing human discomfort, machinery and equipment failure, and affecting the quality of a manufacturing process. When identifiable transmission paths are discernible, vibrations from the source can be isolated from the rest of the system and this prevents or minimises the problems. The approach proposed here for vibration isolation is active force cancellation at points close to the vibration source. It uses force feedback for multiple-input and multiple-output control at the mounting locations. This is particularly attractive for rigid mounting of machine on relative flexible base where machine alignment and motions are to be restricted. The force transfer function matrix is used as a disturbance rejection performance specification for the design of MIMO controllers. For machine soft-mounted via flexible isolators, a model for this matrix has been derived. Under certain conditions, a simple multiplicative uncertainty model is obtained that shows the amount of perturbation a flexible base has on the machine-isolator-rigid base transmissibility matrix. Such a model is very suitable for use with robust control design paradigm. A different model is derived for the machine on hard-mounts without the flexible isolators. With this model, the level of force transmitted from a machine to a final mounting structure using the measurements for the machine running on another mounting structure can be determined. The two mounting structures have dissimilar dynamic characteristics. Experiments have verified the usefulness of the expression. The model compares well with other methods in the literature. The disadvantage lies with the large amount of data that has to be collected. Active force cancellation is demonstrated on an experimental rig using an AC industrial motor hard-mounted onto a relative flexible structure. The force transfer function matrix, determined from measurements, is used to design H and Static Output Feedback controllers. Both types of controllers are stable and robust to modelling errors within the identified frequency range. They reduce the RMS of transmitted force by between 30?80% at all mounting locations for machine running at 1340 rpm. At the rated speed of 1440 rpm only the static gain controller is able to provide 30?55% reduction at all locations. The H controllers on the other hand could only give a small reduction at one mount location. This is due in part to the deficient of the model used in the design. Higher frequency dynamics has been ignored in the model. This can be resolved by the use of a higher order model that can result in a high order controller. A low order static gain controller, with some tuning, performs better. But it lacks the analytical framework for analysis and design.

Published
2000
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42. Graphene Seals for in situ TEM in Catalysis

Author

Bjørnlund, Anton S, primary, Ambjørner, Hjalte R, additional, Bonczyk, Tobias G, additional, Dollekamp, Edwin, additional, Kaas, Lau M, additional, Colding-Fagerholt, Sofie, additional, Mølhave, Kristian S, additional, Damsgaard, Christian D, additional, Helveg, Stig, additional, and Vesborg*, Peter C K, additional

Published
2023
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45. Lipidomic Profiling Reveals Concerted Temporal Patterns of Functionally Related Lipids in Aedes aegypti Females Following Blood Feeding

Author

Lau, M-J, Nie, S, Yang, Q, Harshman, LG, Mao, C, Williamson, NA, Hoffmann, AA, Lau, M-J, Nie, S, Yang, Q, Harshman, LG, Mao, C, Williamson, NA, and Hoffmann, AA

Abstract

We conducted a lipidomic analysis of the whole body of female Aedes aegypti mosquitoes at different time points over the course of feeding and reproduction. There were temporal biphasic increases of more than 80% of lipids identified at the time of feeding and from 16 h to 30 h post blood meal (PBM). During these two increases, the abundance of many lipids dropped while body weight remained stable, probably reflecting blood lipid digestion and the synthesis of vitellogenin in this period. A concerted temporal pattern was particularly strong at the second peak for membrane and signalling lipids such as phosphatidylethanolamine (PE), phosphatidylinositol (PI), cardiolipin (CL), hexosylceramide (HexCer) and lyso-phosphatidic acid (LPA). Lyso-glycerophospholipids showed three distinct change patterns that are functionally related: Lyso-PE and Lyso-phosphatidylcholine (LPC), which are membrane lipids, showed little change; LPA, a signalling lipid, showed a significant increase from 16 to 30 h PBM; Lyso-PI, a bioactive lipid, and both lyso-phosphatidylglycerol (LPG) and lyso-phosphatidylserine (LPS), which are bacterial membrane lipids, showed one significant increase from the time of feeding to 16 h post blood meal. The result of our study on the anautogenous insect Ae. aegypti point to specific lipids likely to be important in the reproductive process with a role in the formation and growth of ovarian follicles.

Published
2023

46. Histopathology images predict multi-omics aberrations and prognoses in colorectal cancer patients

Author

Tsai, P.-C. (Pei-Chen), Lee, T.-H. (Tsung-Hua), Kuo, K.-C. (Kun-Chi), Su, F.-Y. (Fang-Yi), Lee, T. M. (Tsung-Lu Michael), Marostica, E. (Eliana), Ugai, T. (Tomotaka), Zhao, M. (Melissa), Lau, M. C. (Mai Chan), Väyrynen, J. P. (Juha P.), Giannakis, M. (Marios), Takashima, Y. (Yasutoshi), Kahaki, S. M. (Seyed Mousavi), Wu, K. (Kana), Song, M. (Mingyang), Meyerhardt, J. A. (Jeffrey A.), Chan, A. T. (Andrew T.), Chiang, J.-H. (Jung-Hsien), Nowak, J. (Jonathan), Ogino, S. (Shuji), Yu, K.-H. (Kun-Hsing), Tsai, P.-C. (Pei-Chen), Lee, T.-H. (Tsung-Hua), Kuo, K.-C. (Kun-Chi), Su, F.-Y. (Fang-Yi), Lee, T. M. (Tsung-Lu Michael), Marostica, E. (Eliana), Ugai, T. (Tomotaka), Zhao, M. (Melissa), Lau, M. C. (Mai Chan), Väyrynen, J. P. (Juha P.), Giannakis, M. (Marios), Takashima, Y. (Yasutoshi), Kahaki, S. M. (Seyed Mousavi), Wu, K. (Kana), Song, M. (Mingyang), Meyerhardt, J. A. (Jeffrey A.), Chan, A. T. (Andrew T.), Chiang, J.-H. (Jung-Hsien), Nowak, J. (Jonathan), Ogino, S. (Shuji), and Yu, K.-H. (Kun-Hsing)

Abstract

Histopathologic assessment is indispensable for diagnosing colorectal cancer (CRC). However, manual evaluation of the diseased tissues under the microscope cannot reliably inform patient prognosis or genomic variations crucial for treatment selections. To address these challenges, we develop the Multi-omics Multi-cohort Assessment (MOMA) platform, an explainable machine learning approach, to systematically identify and interpret the relationship between patients’ histologic patterns, multi-omics, and clinical profiles in three large patient cohorts (n = 1888). MOMA successfully predicts the overall survival, disease-free survival (log-rank test P-value<0.05), and copy number alterations of CRC patients. In addition, our approaches identify interpretable pathology patterns predictive of gene expression profiles, microsatellite instability status, and clinically actionable genetic alterations. We show that MOMA models are generalizable to multiple patient populations with different demographic compositions and pathology images collected from distinctive digitization methods. Our machine learning approaches provide clinically actionable predictions that could inform treatments for colorectal cancer patients.

Published
2023

47. Spatially resolved multimarker evaluation of CD274 (PD-L1)/PDCD1 (PD-1) immune checkpoint expression and macrophage polarisation in colorectal cancer

Author

Elomaa, H. (Hanna), Ahtiainen, M. (Maarit), Väyrynen, S. A. (Sara A.), Ogino, S. (Shuji), Nowak, J. A. (Jonathan A.), Lau, M. C. (Mai Chan), Helminen, O. (Olli), Wirta, E.-V. (Erkki-Ville), Seppälä, T. T. (Toni T.), Böhm, J. (Jan), Mecklin, J.-P. (Jukka-Pekka), Kuopio, T. (Teijo), Väyrynen, J. P. (Juha P.), Elomaa, H. (Hanna), Ahtiainen, M. (Maarit), Väyrynen, S. A. (Sara A.), Ogino, S. (Shuji), Nowak, J. A. (Jonathan A.), Lau, M. C. (Mai Chan), Helminen, O. (Olli), Wirta, E.-V. (Erkki-Ville), Seppälä, T. T. (Toni T.), Böhm, J. (Jan), Mecklin, J.-P. (Jukka-Pekka), Kuopio, T. (Teijo), and Väyrynen, J. P. (Juha P.)

Abstract

Background: The CD274 (PD-L1)/PDCD1 (PD-1) immune checkpoint interaction may promote cancer progression, but the expression patterns and prognostic significance of PD-L1 and PD-1 in the colorectal cancer microenvironment are inadequately characterised. Methods: We used a custom 9-plex immunohistochemistry assay to quantify the expression patterns of PD-L1 and PD-1 in macrophages, T cells, and tumour cells in 910 colorectal cancer patients. We evaluated cancer-specific mortality according to immune cell subset densities using multivariable Cox regression models. Results: Compared to PD-L1⁻ macrophages, PD-L1⁺ macrophages were more likely M1-polarised than M2-polarised and located closer to tumour cells. PD-L1⁺ macrophage density in the invasive margin associated with longer cancer-specific survival [Ptrend= 0.0004, HR for the highest vs. lowest quartile, 0.52; 95% CI: 0.34–0.78]. T cell densities associated with longer cancer-specific survival regardless of PD-1 expression (Ptrend < 0.005 for both PD-1⁺ and PD-1⁻ subsets). Higher densities of PD-1⁺ T cell/PD-L1⁺ macrophage clusters associated with longer cancer-specific survival (Ptrend < 0.005). Conclusions: PD-L1⁺ macrophages show distinct polarisation profiles (more M1-like), spatial features (greater co-localisation with tumour cells and PD-1⁺ T cells), and associations with favourable clinical outcome. Our comprehensive multimarker assessment could enhance the understanding of immune checkpoints in the tumour microenvironment and promote the development of improved immunotherapies.

Published
2023

48. Bayesian risk prediction model for colorectal cancer mortality through integration of clinicopathologic and genomic data

Author

Zhao, M. (Melissa), Lau, M. C. (Mai Chan), Haruki, K. (Koichiro), Väyrynen, J. P. (Juha P.), Gurjao, C. (Carino), Väyrynen, S. A. (Sara A.), Costa, A. D. (Andressa Dias), Borowsky, J. (Jennifer), Fujiyoshi, K. (Kenji), Arima, K. (Kota), Hamada, T. (Tsuyoshi), Lennerz, J. K. (Jochen K.), Fuchs, C. S. (Charles S.), Nishihara, R. (Reiko), Chan, A. T. (Andrew T.), Ng, K. (Kimmie), Zhang, X. (Xuehong), Meyerhardt, J. A. (Jeffrey A.), Song, M. (Mingyang), Wang, M. (Molin), Giannakis, M. (Marios), Nowak, J. A. (Jonathan A.), Yu, K.-H. (Kun-Hsing), Ugai, T. (Tomotaka), Ogino, S. (Shuji), Zhao, M. (Melissa), Lau, M. C. (Mai Chan), Haruki, K. (Koichiro), Väyrynen, J. P. (Juha P.), Gurjao, C. (Carino), Väyrynen, S. A. (Sara A.), Costa, A. D. (Andressa Dias), Borowsky, J. (Jennifer), Fujiyoshi, K. (Kenji), Arima, K. (Kota), Hamada, T. (Tsuyoshi), Lennerz, J. K. (Jochen K.), Fuchs, C. S. (Charles S.), Nishihara, R. (Reiko), Chan, A. T. (Andrew T.), Ng, K. (Kimmie), Zhang, X. (Xuehong), Meyerhardt, J. A. (Jeffrey A.), Song, M. (Mingyang), Wang, M. (Molin), Giannakis, M. (Marios), Nowak, J. A. (Jonathan A.), Yu, K.-H. (Kun-Hsing), Ugai, T. (Tomotaka), and Ogino, S. (Shuji)

Abstract

Routine tumor-node-metastasis (TNM) staging of colorectal cancer is imperfect in predicting survival due to tumor pathobiological heterogeneity and imprecise assessment of tumor spread. We leveraged Bayesian additive regression trees (BART), a statistical learning technique, to comprehensively analyze patient-specific tumor characteristics for the improvement of prognostic prediction. Of 75 clinicopathologic, immune, microbial, and genomic variables in 815 stage II–III patients within two U.S.-wide prospective cohort studies, the BART risk model identified seven stable survival predictors. Risk stratifications (low risk, intermediate risk, and high risk) based on model-predicted survival were statistically significant (hazard ratios 0.19–0.45, vs. higher risk; P < 0.0001) and could be externally validated using The Cancer Genome Atlas (TCGA) data (P = 0.0004). BART demonstrated model flexibility, interpretability, and comparable or superior performance to other machine-learning models. Integrated bioinformatic analyses using BART with tumor-specific factors can robustly stratify colorectal cancer patients into prognostic groups and be readily applied to clinical oncology practice.

Published
2023

49. Justitsministeren behandler forskere som politiske modstandere

Author

Autzen, Anton A. A., Vallgårda, Karen, Pristed, Birgitte Beck, Kropp, Kristoffer, Jønsson, Alexandra B. R., Hansen, Niels Chr., Kristensen, Peter Marcus, Laustsen-Kiel, Andreas Hougaard, Andersen, Peter Ebert, Høyland-Kroghsbo, Nina Molin, Eriksen, Janus Juul, Jensen, Louise Kruse, Bjørk, Anders Anker, Damgaard, Rune Busk, Clemmensen, Christoffer, Danbolt, Mathias, Sylow, Lykke, Andersen, Lau M., Kristensen, Line Burholt, Autzen, Anton A. A., Vallgårda, Karen, Pristed, Birgitte Beck, Kropp, Kristoffer, Jønsson, Alexandra B. R., Hansen, Niels Chr., Kristensen, Peter Marcus, Laustsen-Kiel, Andreas Hougaard, Andersen, Peter Ebert, Høyland-Kroghsbo, Nina Molin, Eriksen, Janus Juul, Jensen, Louise Kruse, Bjørk, Anders Anker, Damgaard, Rune Busk, Clemmensen, Christoffer, Danbolt, Mathias, Sylow, Lykke, Andersen, Lau M., and Kristensen, Line Burholt

Abstract

De lever i en parallelvirkelighed, mener Peter Hummelgaard om de forskere, der modsiger hans politiske forslag. Men når forskere på den måde bliver behandlet som politiske modstandere, skader det i længden både samfundet og politikerne selv.

Published
2023

50. Vaccine-preventable hospitalisations in adult mental health service users: a population study.

Author

Sara, G, Gould, P, Curtis, J, Chen, W, Lau, M, Ramanuj, P, Currow, D, Burgess, P, Sara, G, Gould, P, Curtis, J, Chen, W, Lau, M, Ramanuj, P, Currow, D, and Burgess, P

Abstract

BACKGROUND: Vaccine-preventable conditions cause preventable illness and may increase mortality in people living with mental illness. We examined how risks of hospitalisation for a wide range of vaccine-preventable conditions varied by age and sex among mental health (MH) service users. METHODS: Linked population data from New South Wales (NSW), Australia were used to identify vaccine-preventable hospitalisations (VPH) for 19 conditions from 2015 to 2020. Adult MH service users (n = 418 915) were compared to other NSW residents using incidence rates standardised for age, sex and socioeconomic status. Secondary analyses examined admissions for COVID-19 to September 2021. RESULTS: We identified 94 180 VPH of which 41% were influenza, 33% hepatitis B and 10% herpes zoster. MH service users had more VPH admissions [adjusted incidence rate ratio (aIRR) 3.2, 95% CI 3.1-3.3]. Relative risks were highest for hepatitis (aIRR 4.4, 95% CI 4.3-4.6), but elevated for all conditions including COVID-19 (aIRR 2.0, 95% CI 1.9-2.2). MH service users had a mean age of 9 years younger than other NSW residents at first VPH admission, with the largest age gap for vaccine-preventable pneumonias (11-13 years younger). The highest relative risk of VPH was among MH service users aged 45-65. CONCLUSIONS: MH service users have increased risk of hospitalisation for many vaccine-preventable conditions. This may be due to reduced vaccination rates, more severe illness requiring hospitalisation, greater exposure to infectious conditions or other factors. People living with mental illness should be prioritised in vaccination strategies.

Published
2023

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