المؤلفون: Powell, Diana, Feinstein, Adina D., Lee, Elspeth K. H., Zhang, Michael, Tsai, Shang-Min, Taylor, Jake, Kirk, James, Bell, Taylor, Barstow, Joanna K., Gao, Peter, Bean, Jacob L., Blecic, Jasmina, Chubb, Katy L., Crossfield, Ian J. M., Jordan, Sean, Kitzmann, Daniel, Moran, Sarah E., Morello, Giuseppe, Moses, Julianne I., Welbanks, Luis, Yang, Jeehyun, Zhang, Xi, Ahrer, Eva-Maria, Bello-Arufe, Aaron, Brande, Jonathan, Casewell, S. L., Crouzet, Nicolas, Cubillos, Patricio E., Demory, Brice-Olivier, Dyrek, Achrène, Flagg, Laura, Hu, Renyu, Inglis, Julie, Jones, Kathryn D., Kreidberg, Laura, López-Morales, Mercedes, Lagage, Pierre-Olivier, Valdés, Erik A. Meier, Miguel, Yamila, Parmentier, Vivien, Piette, Anjali A. A., Rackham, Benjamin V., Radica, Michael, Redfield, Seth, Stevenson, Kevin B., Wakeford, Hannah R., Aggarwal, Keshav, Alam, Munazza K., Batalha, Natalie M., Batalha, Natasha E., Benneke, Björn, Berta-Thompson, Zach K., Brady, Ryan P., Caceres, Claudio, Carter, Aarynn L., Désert, Jean-Michel, Harrington, Joseph, Iro, Nicolas, Line, Michael R., Lothringer, Joshua D., MacDonald, Ryan J., Mancini, Luigi, Molaverdikhani, Karan, Mukherjee, Sagnick, Nixon, Matthew C., Oza, Apurva V., Palle, Enric, Rustamkulov, Zafar, Sing, David K., Steinrueck, Maria E., Venot, Olivia, Wheatley, Peter J., Yurchenko, Sergei N.

المصدر: Nature 626, 979-983 (2024)

مصطلحات موضوعية: Astrophysics - Earth and Planetary Astrophysics

الوصف: The recent inference of sulphur dioxide (SO$_2$) in the atmosphere of the hot ($\sim$1100 K), Saturn-mass exoplanet WASP-39b from near-infrared JWST observations suggests that photochemistry is a key process in high temperature exoplanet atmospheres. This is due to the low ($<$1 ppb) abundance of SO$_2$ under thermochemical equilibrium, compared to that produced from the photochemistry of H$_2$O and H$_2$S (1-10 ppm). However, the SO$_2$ inference was made from a single, small molecular feature in the transmission spectrum of WASP-39b at 4.05 $\mu$m, and therefore the detection of other SO$_2$ absorption bands at different wavelengths is needed to better constrain the SO$_2$ abundance. Here we report the detection of SO$_2$ spectral features at 7.7 and 8.5 $\mu$m in the 5-12 $\mu$m transmission spectrum of WASP-39b measured by the JWST Mid-Infrared Instrument (MIRI) Low Resolution Spectrometer (LRS). Our observations suggest an abundance of SO$_2$ of 0.5-25 ppm (1$\sigma$ range), consistent with previous findings. In addition to SO$_2$, we find broad water vapour absorption features, as well as an unexplained decrease in the transit depth at wavelengths longer than 10 $\mu$m. Fitting the spectrum with a grid of atmospheric forward models, we derive an atmospheric heavy element content (metallicity) for WASP-39b of $\sim$7.1-8.0 $\times$ solar and demonstrate that photochemistry shapes the spectra of WASP-39b across a broad wavelength range.
Comment: Published in Nature

الوصول الحر: http://arxiv.org/abs/2407.07965Test

المؤلفون: Feinstein, Zachary, Halaj, Grzegorz, Sojmark, Andreas

مصطلحات موضوعية: Quantitative Finance - Risk Management, Quantitative Finance - Mathematical Finance

الوصف: We build a balance sheet-based model to capture run risk, i.e., a reduced potential to raise capital from liquidity buffers under stress, driven by depositor scrutiny and further fueled by fire sales in response to withdrawals. The setup is inspired by the Silicon Valley Bank (SVB) meltdown in March 2023 and our model may serve as a supervisory analysis tool to monitor build-up of balance sheet vulnerabilities. Specifically, we analyze which characteristics of the balance sheet are critical in order for banking system regulators to adequately assess run risk and resilience. By bringing a time series of SVB's balance sheet data to our model, we are able to demonstrate how changes in the funding and respective asset composition made SVB prone to run risk, as they were increasingly relying on held-to-maturity, aka hidden-to-maturity, accounting standards, masking revaluation losses in securities portfolios. Finally, we formulate a tractable optimisation problem to address the designation of held-to-maturity assets and quantify banks' ability to hold these assets without resorting to remarking. By calibrating this to SVB's balance sheet data, we shed light on the bank's funding risk and implied risk tolerance in the years 2020--22 leading up to its collapse.

الوصول الحر: http://arxiv.org/abs/2407.03285Test

المؤلفون: Nedkova, Kalina V., Häußler, Boris, Marchesini, Danilo, Brammer, Gabriel B., Feinstein, Adina D., Johnston, Evelyn J., Kartaltepe, Jeyhan S., Koekemoer, Anton M., Martis, Nicholas S., Muzzin, Adam, Rafelski, Marc, Shipley, Heath V., Skelton, Rosalind E., Stefanon, Mauro, van der Wel, Arjen, Whitaker, Katherine E.

مصطلحات موضوعية: Astrophysics - Astrophysics of Galaxies

الوصف: Using deep imaging from the CANDELS and HFF surveys, we present bulge+disc decompositions with GalfitM for $\sim$17,000 galaxies over $0.2 \leq z\leq 1.5$. We use various model parameters to select reliable samples of discs and bulges, and derive their stellar masses using an empirically calibrated relation between mass-to-light ratio and colour. Across our entire redshift range, we show that discs follow stellar mass-size relations that are consistent with those of star-forming galaxies, suggesting that discs primarily evolve via star formation. In contrast, the stellar mass-size relations of bulges are mass-independent. Our novel dataset further enables us to separate components into star-forming and quiescent based on their specific star formation rates. We find that both star-forming discs and star-forming bulges lie on stellar mass-size relations that are similar to those of star-forming galaxies, while quiescent discs are typically smaller than star-forming discs and lie on steeper relations, implying distinct evolutionary mechanisms. Similar to quiescent galaxies, quiescent bulges show a flattening in the stellar mass-size relation at $\sim$10$^{10}$M$_\odot$, below which they show little mass dependence. However, their best-fitting relations have lower normalisations, indicating that at a given mass, bulges are smaller than quiescent galaxies. Finally, we obtain rest-frame colours for individual components, showing that bulges typically have redder colours than discs, as expected. We visually derive UVJ criteria to separate star-forming and quiescent components and show that this separation agrees well with component colour. HFF bulge+disc decomposition catalogues used for these analyses are publicly released with this paper.
Comment: 30 pages, 18 figures, and 6 tables. Resubmitted to MNRAS after addressing a thorough and constructive referee report

الوصول الحر: http://arxiv.org/abs/2406.14613Test

المؤلفون: Aubert, M., Rosnet, P., Popovic, B., Ruppin, F., Smith, M., Rigault, M., Dimitriadis, G., Goobar, A., Johansson, J., Barjou-Delayre, C., Burgaz, U., Carreres, B., Feinstein, F., Fouchez, D., Galbany, L., Ginolin, M., de Jaeger, T., Kasliwal, M. M., Kim, Y. -L., Lacroix, L., Masci, F. J., Müller-Bravo, T. E., Racine, B., Ravoux, C., Regnault, N., Riddle, R. L., Rosselli, D., Rusholme, B., Smith, R., Sollerman, J., Terwel, J. H., Townsend, A.

مصطلحات موضوعية: Astrophysics - Cosmology and Nongalactic Astrophysics

الوصف: The unprecedented statistics of detected Type Ia supernovae (SNe Ia) brought by the Zwicky Transient Facility enables us to probe the impact of the Large-Scale Structure on the properties of these objects. The goal of this paper is to explore the possible impact of the under-dense part of the large-scale structure on the intrinsic SALT2 light curve properties of SNe Ia and uncover possible biases in SN Ia analyses. With a volume-limited selection of ZTF-Cosmo-DR2 Type Ia supernovae overlapping with the SDSS-DR7 survey footprint, we investigate the distribution of their properties with regard to voids detected in the SDSS-DR7 galaxy sample. We further use Voronoi volumes as proxy for local density environments within the large-scale structure. We find a moderate dependency of the stretch toward the localisation around the void centre and none when considering colour. The local Voronoi volumes mostly affect the fraction of low/high stretch supernovae. With the current statistics available, we consider that the impact of high or low local density environment can be considered as a proxy for the colour of the host galaxy. Under-dense environments should not cause any biases in supernova analyses.
Comment: 10 pages, 8 figures. Submitted to A&A

الوصول الحر: http://arxiv.org/abs/2406.11680Test

المؤلفون: Popovic, B., Rigault, M., Smith, M., Ginolin, M., Goobar, A., Kenworthy, W. D., Ganot, C., Ruppin, F., Dimitriadis, G., Johansson, J., Amenouche, M., Aubert, M., Barjou-Delayre, C., Burgaz, U., Carreres, B., Feinstein, F., Fouchez, D., Galbany, L., de Jaeger, T., Kim, Y. -L., Lacroix, L., Nugent, P. E., Racine, B., Rosselli, D., Rosnet, P., Sollerman, J., Hale, D., Laher, R., Müller-Bravo, T. E., Reed, R., Rusholme, B., Terwel, J.

مصطلحات موضوعية: Astrophysics - Cosmology and Nongalactic Astrophysics, Astrophysics - Astrophysics of Galaxies

الوصف: Type Ia supernova (SNIa) are excellent probes of local distance, and the increasing sample sizes of SNIa have driven an increased need to study the associated systematic uncertainties and improve the standardisation methods in preparation for the next generation of cosmological surveys into the dark energy equation-of-state $w$. We aim to probe the potential change in the SNIa standardisation parameter $c$ with redshift and the host-galaxy of the supernova. Improving the standardisation of SNIa brightnesses will require accounting for the relationship between the host and the SNIa, and potential shifts in the SNIa standardisation parameters with redshift will cause biases in the recovered cosmology. Here, we assemble a volume-limited sample of ~3000 likely SNIa across a redshift range of $z = 0.015$ to $z = 0.36$. This sample is fitted with changing mass and redshift bins to determine the relationship between intrinsic properties of SNe Ia and their redshift and host galaxy parameters. We then investigate the colour-luminosity parameter $\beta$ as a further test of the SNIa standardisation process. We find that the changing colour distribution of SNe Ia with redshift is driven by dust at a confidence of $>4\sigma$. Additionally, we show a strong correlation between the host galaxy mass and the colour-luminosity coefficient $\beta$ ($> 4\sigma$), even when accounting for the quantity of dust in a host galaxy.

الوصول الحر: http://arxiv.org/abs/2406.06215Test

المؤلفون: Rigault, M., Smith, M., Regnault, N., Kenworthy, D. W., Maguire, K., Goobar, A., Dimitriadis, G., Amenouche, M., Aubert, M., Barjou-Delayre, C., Bellm, C. E., Burgaz, U., Carreres, B., Copin, Y., Deckers, M., de Jaeger, T., Dhawan, S., Feinstein, F., Fouchez, D., Galbany, L., Ginolin, M., Graham, J. M., Kim, Y. -L., Kowalski, M., Kuhn, D., Kulkarni, R. S., Muller-Bravo, E. T., Nordin, K., Popovic, M., Purdum, J., Rosnet, P., Rosselli, D., Racine, B., Ruppin, F., Sollerman, J., Terwel, H. J., Townsend, A.

مصطلحات موضوعية: Astrophysics - Cosmology and Nongalactic Astrophysics

الوصف: Type Ia supernova (SN Ia) cosmology relies on the estimation of lightcurve parameters to derive precision distances that leads to the estimation of cosmological parameters. The empirical SALT2 lightcurve modeling that relies on only two parameters, a stretch x1, and a color c, has been used by the community for almost two decades. In this paper we study the ability of the SALT2 model to fit the nearly 3000 cosmology-grade SN Ia lightcurves from the second release of the Zwicky Transient Facility (ZTF) cosmology science working group. While the ZTF data was not used to train SALT2, the algorithm is modeling the ZTF SN Ia optical lightcurves remarkably well, except for lightcurve points prior to -10 d from maximum, where the training critically lacks statistics. We find that the lightcurve fitting is robust against the considered choice of phase-range, but we show the [-10; +40] d range to be optimal in terms of statistics and accuracy. We do not detect any significant features in the lightcurve fit residuals that could be connected to the host environment. Potential systematic population differences related to the SN Ia host properties might thus not be accountable for by the addition of extra lightcurve parameters. However, a small but significant inconsistency between residuals of blue- and red-SN Ia strongly suggests the existence of a phase-dependent color term, with potential implications for the use of SNe Ia in precision cosmology. We thus encourage modellers to explore this avenue and we emphasize the importance that SN Ia cosmology must include a SALT2 retraining to accurately model the lightcurves and avoid biasing the derivation of cosmological parameters.
Comment: 10 pages, 9 figures. Submitted to Astronomy and Astrophysics

الوصول الحر: http://arxiv.org/abs/2406.02073Test

المؤلفون: Ginolin, M., Rigault, M., Copin, Y., Popovic, B., Dimitriadis, G., Goobar, A., Johansson, J., Maguire, K., Nordin, J., Smith, M., Aubert, M., Barjou-Delayre, C., Burgaz, U., Carreres, B., Dhawan, S., Deckers, M., Feinstein, F., Fouchez, D., Galbany, L., Ganot, C., de Jaeger, T., Kim, Y. -L., Kuhn, D., Lacroix, L., Müller-Bravo, T. E., Nugent, P., Racine, B., Rosnet, P., Rosselli, D., Ruppin, F., Sollerman, J., Terwel, J. H., Townsend, A., Dekany, R., Graham, M., Kasliwal, M., Groom, S. L., Purdum, J., Rusholme, B., van der Walt, S.

مصطلحات موضوعية: Astrophysics - Cosmology and Nongalactic Astrophysics, Astrophysics - Astrophysics of Galaxies

الوصف: As Type Ia supernova cosmology transitions from a statistics dominated to a systematics dominated era, it is crucial to understand leftover unexplained uncertainties affecting their luminosity, such as the ones stemming from astrophysical biases. Indeed, SNe Ia are standardisable candles, whose absolute magnitude reach a 0.15~mag scatter once empirical correlations with their lightcurve stretch and colour and with their environment are accounted for. In this paper, we investigate how the standardisation process of SNe Ia depends on environment, to ultimately reduce their scatter in magnitude, focusing on colour standardisation. We use the volume-limited ZTF SN Ia DR2 sample, which offers unprecedented statistics for the low redshift ($z<0.06$) range. We first study the colour distribution, focusing on the effects of dust, to then select a dustless subsample of objects from low stellar mass environments and from the outskirts of their host galaxies. We then look at the colour-residuals relation and its associated parameter $\beta$. Finally, we investigate the colour dependency of the environment-dependent magnitude offsets (steps), to try to disentangle intrinsic and extrinsic colour origin. Our sample probes well the red tail of the colour distribution, up to $c=0.8$. The dustless sample exhibits a significantly lower red tail ($4.6\sigma$) in comparison to the whole sample. This suggests that reddening above $c\geq0.2$ is dominated by host interstellar dust absorption. Looking at the colour-residuals relation, we find it to be linear with lightcurve colour. We show hints of a potential evolution of $\beta$ with host stellar mass at a $2.5\sigma$ level. Finally, unlike recent claims from the literature, we see no evolution of steps as a function of lightcurve colour, suggesting that dust may not be the dominating mechanism responsible for the environmental dependency of SNe Ia magnitude.
Comment: 10 pages, 7 figures, submitted to Astronomy and Astrophysics

الوصول الحر: http://arxiv.org/abs/2406.02072Test

المؤلفون: Ruppin, F., Rigault, M., Ginolin, M., Dimitriadis, G., Goobar, A., Johansson, J., Maguire, K., Nordin, J., Smith, M., Aubert, M., Biedermann, J., Copin, Y., Burgaz, U., Carreres, B., Feinstein, F., Fouchez, D., Muller-Bravo, T. E., Galbany, L., Groom, S. L., Kenworthy, W. D., Kim, Y. -L., Laher, R. R., Nugent, P., Popovic, B., Purdum, J., Racine, B., Rosnet, P., Rosselli, D., Sollerman, J., Terwel, J. H.

مصطلحات موضوعية: Astrophysics - Cosmology and Nongalactic Astrophysics

الوصف: Understanding the impact of the astrophysical environment on Type Ia supernova (SN Ia) properties is crucial to minimize systematic uncertainties in cosmological analyses based on this probe. We investigate the dependence of the SN Ia SALT2.4 light-curve stretch on the distance from their nearest galaxy cluster to study a potential effect of the intracluster medium (ICM) environment on SN Ia intrinsic properties. We use the largest SN Ia sample to date and cross-match it with existing X-ray, Sunyaev-Zel'dovich, and optical cluster catalogs in order to study the dependence between stretch and distance to the nearest detected cluster from each SN Ia. We model the underlying stretch distribution with a Gaussian mixture with relative amplitudes that depend on redshift and cluster-centric distance. We find a significant improvement of the fit quality of the stretch distribution if we include the distance-dependant term in the model with a variation of the Akaike information criterion $\rm{\Delta AIC} = -10.2$. Because of the known correlation between galaxy age and distance from cluster center, this supports previous evidence that the age of the stellar population is the underlying driver of the bimodial shape of the SN Ia stretch distribution. We further compute the evolution of the fraction of quenched galaxies as a function of distance with respect to cluster center from our best-fit model of the SNe Ia stretch distribution and compare it to previous results obtained from $H\alpha$ line measurements, optical broadband photometry, and simulations. We find our estimate to be compatible with these results. The results of this work indicate that SNe Ia searches at high redshift targeted towards clusters to maximize detection probability should be considered with caution as the stretch distribution of the detected sample would be strongly biased towards the old sub-population of SNe Ia.
Comment: Submitted to Astronomy & Astrophysics

الوصول الحر: http://arxiv.org/abs/2406.01108Test

المؤلفون: Ginolin, M., Rigault, M., Smith, M., Copin, Y., Ruppin, F., Dimitriadis, G., Goobar, A., Johansson, J., Maguire, K., Nordin, J., Amenouche, M., Aubert, M., Barjou-Delayre, C., Betoule, M., Burgaz, U., Carreres, B., Deckers, M., Dhawan, S., Feinstein, F., Fouchez, D., Galbany, L., Ganot, C., Harvey, L., de Jaeger, T., Kenworthy, W. D., Kim, Y. -L., Kowalski, M., Kuhn, D., Lacroix, L., Muller-Bravo, T. E., Nugent, P., Popovic, B., Racine, B., Rosnet, P., Rosselli, D., Sollerman, J., Terwel, J. H., Townsend, A., Brugger, J., Bellm, E. C., Kasliwal, M. M., Kulkarni, S., Laher, R. R., Masci, F. J., Riddle, R. L., Sharma, Y.

مصطلحات موضوعية: Astrophysics - Cosmology and Nongalactic Astrophysics

الوصف: To get distances, Type Ia Supernovae magnitudes are corrected for their correlation with lightcurve width and colour. Here we investigate how this standardisation is affected by the SN environment, with the aim to reduce scatter and improve standardisation. We first study the SN Ia stretch distribution, as well as its dependence on environment, as characterised by local and global (g-z) colour and stellar mass. We then look at the standardisation parameter $\alpha$, which accounts for the correlation between residuals and stretch, along with its environment dependence and linearity. We finally compute magnitude offsets between SNe in different astrophysical environments after colour and stretch standardisation, aka steps. This analysis is made possible due to the unprecedented statistics of the ZTF SN Ia DR2 volume-limited sample. The stretch distribution exhibits a bimodal behaviour, as previously found in literature. However, we find the distribution means to decrease with host stellar mass at a 9.0$\sigma$ significance. We demonstrate, at the 14.3$\sigma$ level, that the stretch-magnitude relation is non-linear, challenging the usual linear stretch-residuals relation. Fitting for a broken-$\alpha$ model, we indeed find two different slopes between stretch regimes ($x_1<-0.49\pm0.06$): $\alpha_{low}=0.28\pm0.01$ and $\alpha_{high}=0.09\pm0.01$, a $\Delta_{\alpha}=-0.19\pm0.01$ difference. As the relative proportion of SNe Ia in the high-/low-stretch modes evolves with redshift and environment, this implies that a linear $\alpha$ also evolves with redshift and environment. Concerning the environmental magnitude offset $\gamma$, we find it to be greater than 0.14 mag regardless of the considered environmental tracer used (local or global colour and stellar mass), all measured at the $\geq 6\sigma$ level, increased to $\sim0.18\pm0.01$ mag when accounting for the stretch-non linearity.
Comment: 15 pages, 9 figures, submitted to Astronomy and Astrophysics

الوصول الحر: http://arxiv.org/abs/2405.20965Test

المؤلفون: Carreres, B., Rosselli, D., Bautista, J. E., Feinstein, F., Fouchez, D., Racine, B., Ravoux, C., Sanchez, B., Dimitriadis, G., Goobar, A., Johansson, J., Nordin, J., Rigault, M., Smith, M., Amenouche, M., Aubert, M., Barjou-Delayre, C., Burgaz, U., Kenworthy, W. D'Arcy, De Jaeger, T., Dhawan, S., Galbany, L., Ginolin, M., Kuhn, D., Kowalski, M., Müller-Bravo, T. E., Nugent, P. E., Popovic, B., Rosnet, P., Ruppin, F., Sollerman, J., Terwel, J. H., Townsend, A., Groom, S. L., Kulkarni, S. R., Purdum, J., Rusholme, B., Sravan, N.

مصطلحات موضوعية: Astrophysics - Cosmology and Nongalactic Astrophysics

الوصف: SNe Ia are used to determine the distance-redshift relation and build the Hubble diagram. Neglecting their host-galaxy peculiar velocities (PVs) may bias the measurement of cosmological parameters. The smaller the redshift, the larger the effect is. We use realistic simulations of SNe Ia observed by the Zwicky Transient Facility (ZTF) to investigate the effect of different methods to take into account PVs. We study the impact of neglecting galaxy PVs and their correlations in an analysis of the SNe Ia Hubble diagram. We find that it is necessary to use the PV full covariance matrix computed from the velocity power spectrum to take into account the sample variance. Considering the results we have obtained using simulations, we determine the PV systematic effects in the context of the ZTF DR2 SNe Ia sample. We determine the PV impact on the intercept of the Hubble diagram, $a_B$, which is directly linked to the measurement of $H_0$. We show that not taking into account PVs and their correlations results in a shift of the $H_0$ value of about $1.0$km.s$^{-1}$.Mpc$^{-1}$ and a slight underestimation of the $H_0$ error bar.
Comment: 12 pages, 4 figures

الوصول الحر: http://arxiv.org/abs/2405.20409Test