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Characterization of filter photometer artifacts in soot and dust measurements - laboratory and ambient experiments using a traceably calibrated aerosol absorption reference
No full textAbstract. A novel reference absorption instrument based on photothermal interferometry – the dual-wavelength photothermal aerosol absorption monitor PTAAM-2λ – and scattering measurements are used to characterize filter photometer artifacts in measurements of absorption coefficients of soot- and dust-dominated aerosol samples within laboratory and ambient campaigns. We provide, for different aerosol types, reference values of the multiple-scattering parameter, quantifying the artifact introduced by the interaction between the light, the particles, and the filter. The Aethalometer AE33 and the Continuous Light Absorption Photometer (CLAP) were characterized during a laboratory campaign where different soot and mineral dust samples were measured. Furthermore, ambient measurements during a campaign in Granada, Spain, were used to characterize the AE33 and MAAP (Multiangle Absorption Photometer), a pseudo-reference absorption instrument. The laboratory campaign showed significant wavelength dependence of the calibration parameter, the multiple-scattering parameter C. The C of the AE33 at 450 and 808 nm was 4.08 and 3.95 and 6.25 and 5.27 for propane soot and diesel soot, respectively. For the CLAP, the C was 5.10 and 4.26 and 6.79 and 5.80 for propane and diesel soot, respectively. For the different mineral dust samples analyzed in the laboratory, the C at 450 nm ranged between 2.74 and 3.03 for the AE33 and between 2.50 and 2.80 for the CLAP. The ambient measurements at Granada showed an overall C of 4.72 at 450 nm and of 3.90 at 808 nm for the AE33. The results for both the AE33 and the CLAP show a dependence with the particle size, with fine particles having the highest C values and with the C being reduced and leveling off for larger particles. Both the laboratory and the ambient measurements of the AE33 showed overlapping results. The cross-sensitivity to scattering was smaller for the CLAP than for the AE33. The values of the cross-sensitivity parameter ms at 450 and 808 nm were 3.0 % and 1.5 % for the AE33 and 2.4 % and 0.9 % for the CLAP. The intercomparison of the MAAP with the PTAAM-2λ during the ambient campaign in Granada showed that the MAAP overestimates the absorption coefficients for 47 % at 637 nm and features a cross-sensitivity to scattering of 2.4 %
Confronting the dark matter capture rate with a continuous gravitational wave probe of local neutron stars
No full textContinuous gravitational waves (CGWs) from various astrophysical sources are one of the many future probes of upcoming gravitational wave (GW) search missions. Neutron stars (NSs) with deformity are one of the leading sources of CGW emissions. In this work, for the first time, a novel attempt to estimate the dark matter (DM) capture rate is performed using CGW as the probe to the local NS population. Competitive bounds on DM capture from the local NS population are reported when compared with DM direct search experiments and other astrophysical observations
Dark matter gamma-ray searches in galaxy clusters
No full textGalaxy clusters are the largest structures in the Universe, being dark matter (DM) dominated objects. For DM decay, they yield the highest expected fluxes with respect to other prime targets. ForDMannihilation, clusters can provide fluxes comparable to dwarf spheroidal galaxies, as long as the contribution from substructures is taken into account. We present the analysis of 12 years of Fermi-LAT data in the direction of 49 clusters. We modelled the expected substructure population in these objects, providing benchmark models to quantify the uncertainty on their contribution to the annihilation flux. From the combined search, we found a signal of 2.5-3.0σ significance, potentially associated with DM or hadronic induced emission from the intracluster region by cosmic rays. Looking into the future, we discuss the prospects of the Cherenkov Telescope Array Observatory (CTAO), to detect diffuse γ-ray emission from the Perseus galaxy cluster. With its improvement in sensitivy of more than one order of magnitude with respect to current IACTs, we derive the tightest constraints for DM decay scenarios in the TeV range, reaching values of τDM ∼ 1027s
Validation of torus mapping dealiasing method on Doppler velocities for use in numerical weather prediction
No full textTraces of queerness
No full textThis presentation looks at queer zines and magazines from Poland and Slovenia in the late socialist and early postsocialist period, a moment of political upheaval and
cultural experimentation. These publications were not
simply reproductions of mainstream media forms, but they
carved out new spaces where sexuality, politics, and
aesthetics intersected. The analysis unfolds in three
steps. First, it provides context for these zines within
their cultural and political moment, as well as tries to
define them. Second, it considers how they crossed media
boundaries by incorporating literary texts, and shows
possible ways of approaching the literary material, from
mapping and cataloguing to discourse analysis. This part
also raises the question of how the use of literature
shaped processes of community-building. Third, we frame
these practices through Sara Ahmed’s notion of queer use
(2019), which emphasizes how objects and spaces can be
repurposed against the grain, releasing latent potentials
and leaving behind queer traces. Ultimately, the
presentation argues that Polish and Slovene queer zines
were not marginal ephemera, but crucial laboratories of
queer world-making, where new forms of communication,
belonging, and cross-border solidarity were tested and
imagined