Cosmology and Nongalactic Astrophysics
Is Dark Energy Changing? Probing the Universe's Expansion with present and future astronomical probes
Mehdi Rezaei, Supriya Pan, Weiqiang Yang et al. (+1 more)
This study explores the possibility of a time-varying dark energy (DE) equation of state (EoS) deviating from -1. We employ a comprehensive
dataset of usual astronomical probes (Type Ia
supernovae,
baryon acoustic oscillations, Big Bang nucleosynthesis, Hubble data, and Planck 2018 CMB) alongside future mock gravitational wave (GW) distance measurements from the Einstein
Telescope. We utilize the Pad'e approximation, a versatile framework encompassing well-known DE models like constant EoS, Chevallier-Polarski-Linder parametrization and other time-evolving DE parametrizations. Within Pad'e parametrization, we examine three specific forms (Pad'e-I, SPad'e-I, Pad'e-II) applied to both spatially flat and non-flat universes. Pad'e-II exhibits particularly interesting features in terms of the evidence of dynamical DE at many standard deviations. Our results can be summarized as follows. Flat Universe: When analyzing the combined
dataset of standard probes (including CMB) with Pad'e-II in a flat universe, we find a strong preference (6.4{\sigma}) for a dynamical (time-varying) DE EoS. This preference remains significant (4.7{\sigma}) even when incorporating future GW data. Non-Flat Universe: In a non-flat universe, the combined standard
datasets (without or with CMB) also indicate dynamical DE EoS at a high confidence level (6.2{\sigma} and 6.4{\sigma}, respectively). The addition of GW data slightly reduces the evidence (3.8{\sigma} and 5.1{\sigma}, respectively), but the preference persists. These results collectively suggest a robust case for dynamical DE in the dark sector. While a non-flat universe is not strongly favored, Pad'e-II hints at a possible closed universe when CMB data is included (with or without GW data).
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All authors Mehdi Rezaei, Supriya Pan, Weiqiang Yang, David F. Mota
Cosmology and Nongalactic Astrophysics
FLAMINGO: Baryonic effects on the weak lensing scattering transform
Mariia Marinichenko, Marcel P. van Daalen, Elena Sellentin et al. (+3 more)
The scattering transform is a wavelet-based statistic capable of capturing non-Gaussian features in weak
lensing (WL) convergence maps and has been proven to tighten cosmological parameter constraints by accessing information beyond two-point functions. However, its application in cosmological inference requires a clear understanding of its sensitivity to astrophysical systematics, the most significant of which are baryonic effects. These processes substantially modify the matter distribution on small to intermediate scales ($k\gtrsim 0.1\,h\,\mathrm{Mpc}^{-1}$), leaving scale-dependent imprints on the WL convergence field. We systematically examine the impact of baryonic feedback on scattering coefficients using full-sky WL convergence maps with Stage IV survey characteristics, generated from the FLAMINGO simulation suite. These simulations include a broad range of feedback models, calibrated to match the observed cluster gas fraction and
galaxy stellar mass function, including systematically shifted variations, and incorporating either thermal or jet-mode AGN feedback. We characterise baryonic effects using a baryonic transfer function defined as the ratio of hydrodynamical to dark-matter-only scattering coefficients. While the coefficients themselves are sensitive to both cosmology and feedback, the transfer function remains largely insensitive to cosmology and shows a strong response to feedback, with suppression reaching up to $10\%$ on scales of $k\gtrsim 0.1\,h\,\mathrm{Mpc}^{-1}$. We also demonstrate that shape noise significantly diminishes the sensitivity of the scattering coefficients to baryonic effects, reducing the suppression from $\sim 2 - 10 \;\%$ to $\sim 1\;\%$, even with 1.5 arcmin Gaussian smoothing. This highlights the need for noise mitigation strategies and high-resolution data in future WL surveys.
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All authors Mariia Marinichenko, Marcel P. van Daalen, Elena Sellentin, Jeger C. Broxterman, Matthieu Schaller, Joop Schaye
High Energy Astrophysical Phenomena
JWST Spectroscopy of SN Ia 2022aaiq and 2024gy: Evidence for Enhanced Central Stable Ni Abundance and a Deflagration-to-Detonation Transition
Lindsey A. Kwok, Chang Liu, Saurabh W. Jha et al. (+48 more)
We present optical + near-infrared (NIR) + mid-infrared (MIR) observations of the normal Type Ia
supernovae (SN Ia) 2022aaiq and 2024gy in the nebular phase, continuously spanning 0.35-28 microns. Medium-resolution JWST spectroscopy reveals novel narrow ($v_{\mathrm{FWHM}}<1500$ km s$^{-1}$) [Ni II] 1.94 and 6.64 micron cores in both events. The MIR [Ni II] 6.64 micron line exhibits a distinct narrow core atop a broader base, indicating a central enhancement of stable Ni. This structure points to high central densities consistent with a near-Chandrasekhar-mass ($M_{\text{Ch}}$) progenitor or a high-
metallicity sub-$M_{\text{Ch}}$ progenitor. From detailed line-profile inversions of SN 2024gy, we derive emissivity profiles for stable iron-group elements (IGEs), radioactive material, and intermediate-mass elements (IMEs), revealing spatially distinct ejecta zones. The [Ni III] 7.35 micron line shows a shallow-to-steep slope transition - a "broken-slope" morphology - that matches predictions for delayed detonation explosions with separated deflagration and detonation ashes. We also reanalyze and compare to archival JWST spectra of SN 2021aefx and the subluminous SN 2022xkq. From the stable Ni luminosities, we infer that SN 2024gy produced ~5-10 times more stable Ni mass than SN 2022xkq, favoring a near-$M_{\text{Ch}}$ scenario for SN 2024gy and sub-$M_{\text{Ch}}$ scenario for SN 2022xkq. These results demonstrate that resolved line profiles, now accessible with JWST, provide powerful diagnostics of explosion geometry, central density, and progenitor mass in SN Ia.
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All authors Lindsey A. Kwok, Chang Liu, Saurabh W. Jha, Stéphane Blondin, Conor Larison, Adam A. Miller, Mi Dai, Ryan J. Foley, Alexei V. Filippenko, Jennifer E. Andrews, Moira Andrews, Katie Auchettl, Carles Badenes, K. Azalee Bostroem, Thomas G. Brink, Cristine Koelln, Kyle W. Davis, Andreas Flörs, Lluís Galbany, Or Graur, D. Andrew Howell, Sahana Kumar, Réka Könyves-Tóth, Natalie LeBaron, Colin W. Macrie, Keiichi Maeda, Kate Maguire, Curtis McCully, Nicolas E. Meza-Retamal, Estefania Padilla Gonzalez, Rüdiger Pakmor, Jeniveve Pearson, Anthony L. Piro, Abigail Polin, Nabeel Rehemtulla, César Rojas-Bravo, David J. Sand, Chita Sangkachan, Michaela Schwab, Huei Sears, Mridweeka Singh, Bhagya M. Subrayan, Kirsty Taggart, Tea Temim, Jacco H. Terwel, Samaporn Tinyanont, József Vinkó, Xiaofeng Wang, J. Craig Wheeler, Yi Yang, WeiKang Zheng
Instrumentation and Methods for Astrophysics
GMIMS-DRAGONS: A Faraday Depth Survey of the Northern Sky Covering 350-1030 MHz
Anna Ordog, Rebecca A. Booth, T.L. Landecker et al. (+25 more)
Polarized synchrotron emission at meter to centimeter wavelengths provides an effective tracer of the
Galactic magnetic field. Calculating Faraday depth, the most useful parameter for mapping the line-of-sight
magnetic field, requires observations covering wide frequency bands with many channels. As part of the Global Magneto-Ionic Medium Survey (GMIMS), we have observed polarized emission spanning 350-1030 MHz over the northern sky, in the declination range ${-20^{\circ}}\leq{\delta}\leq{90^{\circ}}$. We used the 15 m
telescope at the Dominion
Radio Astrophysical Observatory (DRAO), equipped to receive orthogonal circular polarizations, with the Onsala Space Observatory band 1 feed developed for the SKA Project. Angular resolution varies across the band from $1.3^{\circ}$ to $3.6^{\circ}$. A digital spectrometer provided 42 kHz frequency resolution. Data were taken with the
telescope moving rapidly in azimuth and are absolutely calibrated in intensity. Approximately 25% of the data were lost due to
radio-frequency interference. The resolution in Faraday depth is $\sim6$ rad m$^{-2}$, and features as wide as $\sim38$ rad m$^{-2}$ are represented. The median sensitivity of the Faraday depth cube is 11 mK. Approximately 55% of sight-lines in this survey show Faraday complexity. This
dataset, called “DRAO GMIMS of the Northern Sky” (DRAGONS), is the first to probe Faraday depth of the northern sky in its frequency range and will support many scientific investigations. The data will be used to calibrate surveys with higher angular resolution, particularly
Galactic foreground maps from the Canadian Hydrogen Intensity Mapping Experiment, and to provide information on large structures for aperture-synthesis
telescopes, particularly the DRAO Synthesis
Telescope. The data are available through the Canadian Astronomy Data Centre.
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All authors Anna Ordog, Rebecca A. Booth, T.L. Landecker, Ettore Carretti, Alex S. Hill, Jo-Anne C. Brown, Artem Davydov, Leonardo Moutinho Caffarello, Luca B. Galler, Jonas Flygare, Jennifer L. West, A.G. Willis, Mehrnoosh Tahani, G.J. Hovey, Dustin Lagoy, Stephen Harrison, Michael A. Smith, Charl Baard, Rob H. Messing, D. A. Del Rizzo, Benoit Robert, Timothy Robishaw, John M. Dickey, George Morgan, Ian R. Kennedy, Marijke Haverkorn, Andrea Bracco, John Conway
Instrumentation and Methods for Astrophysics
Time-Dilation Methods for Extreme Multiscale Timestepping Problems
Philip F. Hopkins and Elias R. Most
Many astrophysical simulations involve extreme dynamic range of timescales around 'special points' in the domain (e.g. black holes,
stars,
planets, disks,
galaxies, shocks, mixing interfaces), where processes on small scales couple strongly to those on large scales. Adaptive resolution, multi-physics, and hybrid numerical methods have enabled tremendous progress on the spatial, physics, and numerical challenges involved. But often the limiter for following the long timescales of global
evolution is the extremely short numerical timestep required in some subdomains (which leads to their dominating simulation costs). Recently several approaches have been developed for tackling this in problems where the short timescale solution is sampled and then projected as an effective subgrid model over longer timescales (e.g. 'zooming in and out'). We generalize these to a family of models where time
evolution is modulated by a variable but continuous in space-and-time dilation/stretch factor $a({\bf x},\,t)$. This extends previous well-studied approaches (including reduced-speed-of-light and binary orbital dynamics methods), and ensures that the system comes to correct local steady-state solutions, and derive criteria that the dilation factor/timesteps/resolution must obey to ensure good behavior. We present a variety of generalizations to different physics or coupling scales. Compared to previous approaches, this method makes it possible to avoid imprinting arbitrary scales where there is no clear scale-separation, and couples well to Lagrangian or Eulerian methods. It is flexible and easily-implemented and we demonstrate its validity (and limitations) in test problems. We discuss the relationship between these methods and physical time dilation in GRMHD. We demonstrate how this can be used to obtain effective speedup factors exceeding $\gtrsim 10^{4}$ in multiphysics simulations.
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Astrophysics of Galaxies
MaNGA AGN dwarf galaxies (MAD) – IV. Revealing hidden AGN in dwarf galaxies with radio observations
I. Flores, M. Mezcua and V. Rodríguez Morales
Low-mass black holes hosted by
dwarf galaxies offer valuable insights into
galaxy formation and the growth of the massive black holes found in massive
galaxies. Their detection as AGN is challenging due to their low luminosity and compact size. This can be circumvented employing multi-wavelength observational strategies, such as combining optical and
radio observations, which enables the detection of AGN features that may be hidden in single-wavelength analyses We aim to detect any jet-like emission indicative of the presence of an AGN in a sample of four
dwarf galaxies with AGN signatures based on spatially resolved emission line diagnostic diagrams with SDSS MaNGA. Confirming the presence of an AGN will prove IFU spectroscopy to be a resourceful tool for identifying hidden or switched-off AGN. Using VLA
radio observations, we image the
radio emission of the four
dwarf galaxies and derive their integrated
radio flux and luminosity. We compare these to that expected from
star formation processes to determine the origin of the
radio emission and probe if it is consistent with the results of the emission line diagnostic diagrams. We find that one out of the four
galaxies shows AGN
radio emission consistent with the analysis of the MaNGA IFU data. The kinetic jet power of this source is Qjet ~ 1e42 erg / s, indicating that
dwarf galaxies can host
radio jets as powerful as those of massive
radio galaxies. This
galaxy exhibits an AGN
outflow able to escape the gravitational bound produced by the dark matter
halo, along with a decrease in the
star formation rate of the central region. This suggests the presence of negative feedback from the AGN, which could be suppressing
star formation. The other three
galaxies exhibit regions of
radio emission consistent with a
stellar origin and overlapping with the
star-forming regions found in the IFU spectroscopy.
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Astrophysics of Galaxies
BEES: Quasar lifetime measurements from extended rest-optical emission line nebulae at $z\sim6$
Dominika Ďurovčíková, Anna-Christina Eilers, Yuzo Ishikawa et al. (+13 more)
Measurements of
quasar lifetimes at high
redshift indicate that the earliest billion-
solar-mass supermassive black holes (SMBHs) have only been active as luminous
quasars for less than a million years. Recently, extended Ly$\alpha$ nebulae around $z\sim6$
quasars have revealed that these short observed lifetimes are unlikely a sightline-dependent effect. However, the interpretation of Ly$\alpha$ emission is not straightforward due to its resonant nature. In this work, we use rest-frame optical emission lines, which more directly trace photoionization by the
quasar, to unambiguously validate the short line-of-sight
quasar lifetimes observed at early
cosmic epochs. We use deep James Webb Space
Telescope/NIRSpec IFU observations of five $z\sim 6$
quasars with small proximity zones to search for their extended emission line nebulae in H$\alpha$ and [O III]$5007$, and detect extended emission in both emission lines around four
quasars in our sample. We then use the light-crossing time of these nebulae to measure
quasar lifetimes along transverse sightlines. Using their H$\alpha$ nebulae, we also confirm that recombination is likely the dominant emission mechanism behind their previously detected Ly$\alpha$ nebulae. Our results confirm the existence of high-
redshift quasars with extremely short lifetimes, $t_{\rm Q} \lesssim 10^{5}\ {\rm yr}$, hosting billion-
solar-mass black holes, indicating that rapid
accretion is likely responsible for the assembly of SMBHs in the early Universe.
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All authors Dominika Ďurovčíková, Anna-Christina Eilers, Yuzo Ishikawa, Minghao Yue, Marianne Vestergaard, Frederick B. Davies, Jan-Torge Schindler, Xiaohui Fan, Fabrizio Arrigoni Battaia, Marta Volonteri, Robert A. Simcoe, Joseph F. Hennawi, Laura Blecha, Irham T. Andika, Sarah E. I. Bosman, Rebekka Bieri
Astrophysics of Galaxies
The dark matter wake of a galactic bar revealed by multichannel Singular Spectral Analysis
Jason A. S. Hunt, Michael S. Petersen, Martin D. Weinberg et al. (+7 more)
The Milky Way is known to contain a
stellar bar, as are a significant fraction of disc
galaxies across the universe. Our understanding of bar
evolution, both theoretically and through analysis of simulations indicates that bars both grow in amplitude and slow down over time through interaction and angular momentum exchange with the
galaxy's dark matter
halo. Understanding the physical mechanisms underlying this coupling requires modelling of the structural deformations to the potential that are mutually induced between components. In this work we use Basis Function Expansion (BFE) in combination with multichannel Singular Spectral Analysis (mSSA) as a non-parametric analysis tool to illustrate the coupling between the bar and the dark
halo in a single high-resolution isolated barred disc
galaxy simulation. We demonstrate the power of mSSA to extract and quantify explicitly coupled dynamical modes, determining growth rates, pattern speeds and phase lags for different stages of
evolution of the
stellar bar and the dark matter response. BFE & mSSA together grant us the ability to explore the importance and physical mechanisms of bar-
halo coupling, and other dynamically coupled structures across a wide range of dynamical environments.
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All authors Jason A. S. Hunt, Michael S. Petersen, Martin D. Weinberg, Kathryn V. Johnston, Marcel Bernet, Kathryne J. Daniel, Sóley Ó. Hyman, Adrian M. Price-Whelan, Arpit Arora, the EXP Collaboration
Cosmology and Nongalactic Astrophysics
The effect of a short mean free path on HII regions and 21-cm tomography during reionization
Michael M. Wyatt, Steven R. Furlanetto and Mary H. Minasyan
Recent measurements of the mean free path (MFP) of ionizing
photons at $z=6$ find that it is significantly shorter than extrapolations from lower $z$. This has a substantial impact on the
topology of reionization and thus the prospects of
tomography of the 21-cm signal from upcoming
radio interferometers. In this work we develop the first analytic model of reionization which explicitly incorporates the MFP as a free parameter, allowing us to transparently explore its effect on the process. Our model is based on the excursion set formalism with an ionization condition which accounts for absorptions parameterized through the MFP. With the goal of observational comparison, we include additional modifications which make our model particularly suitable for predicting one-point statistics of the ionization field (and 21-cm signal), which are among the fundamental quantities for
tomography. We find that the effect of the MFP is much more significant during the later stages of reionization, and that including a shorter MFP reduces the size of HII regions by around an order of magnitude towards the end of reionization compared with analytic models which do not account for the MFP. We find that the reported MFP value produces a contrast in the 21-cm signal of $\mathcal{O}$(1 mK) or less at resolutions $\theta \sim $ 15–35 arcmin, an order of magnitude below naive estimates and up to a factor of several smaller than when using a larger MFP value extrapolated from low $z$, requiring significantly more sensitivity for imaging. We compare the contrast to noise estimates for arrays similar in size to HERA and SKA-Low and find that SKA has sufficient sensitivity for direct imaging (at the largest scales considered), while the predicted signal will be challenging for arrays similar in size to HERA. Our model indicates that more detailed sensitivity estimates are warranted in the context of a short MFP.
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Instrumentation and Methods for Astrophysics
The Importance of Being Adaptable: An Exploration of the Power and Limitations of Domain Adaptation for Simulation-Based Inference with Galaxy Clusters
Michelle Ntampaka, A. Ciprijanovic, Ana Maria Delgado et al. (+4 more)
The application of deep machine learning methods in astronomy has exploded in the last decade, with new models showing remarkably improved performance on
benchmark tasks. Not nearly enough
attention is given to understanding the models' robustness, especially when the test data are systematically different from the training data, or "out of domain." Domain shift poses a significant challenge for simulation-based inference, where models are trained on simulated data but applied to real observational data. In this paper, we explore domain shift and test domain adaptation methods for a specific scientific case: simulation-based inference for estimating
galaxy cluster masses from X-ray profiles. We build
datasets to mimic simulation-based inference: a training set from the Magneticum simulation, a scatter-augmented training set to capture uncertainties in scaling relations, and a test set derived from the IllustrisTNG simulation. We demonstrate that the Test Set is out of domain in subtle ways that would be difficult to detect without careful analysis. We apply three deep learning methods: a standard neural network (NN), a neural network trained on the scatter-augmented input catalogs, and a Deep Reconstruction-Regression Network (DRRN), a semi-supervised deep model engineered to address domain shift. Although the NN improves results by 17% in the Training Data, it performs 40% worse on the out-of-domain Test Set. Surprisingly, the Scatter-Augmented Neural Network (SANN) performs similarly. While the DRRN is successful in mapping the training and Test Data onto the same latent space, it consistently underperforms compared to a straightforward Yx scaling relation. These results serve as a warning that simulation-based inference must be handled with extreme care, as subtle differences between training simulations and observational data can lead to unforeseen biases creeping into the results.
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All authors Michelle Ntampaka, A. Ciprijanovic, Ana Maria Delgado, John Soltis, John F. Wu, Mikaeel Yunus, John ZuHone
High Energy Astrophysical Phenomena
Characterizing Power Spectra of Density Fluctuations in GRMHD Simulations of Black Hole Accretion Using Taylor's Frozen-in Hypothesis
Pravita Hallur, Lia Medeiros, Pierre Christian et al. (+1 more)
We characterize the spatial power spectrum of density fluctuations in magnetohydrodynamic flows in a suite of high-resolution, long-time-span general relativistic magnetohydrodynamic (GRMHD) simulations. Extracting the local spatial power spectrum in curved spacetime directly from GRMHD simulations can be challenging for several conceptual and mechanical reasons, including choices of the reference frame, the non-uniform co-ordinate grid of the outputs and limited resolution. Taylor's frozen-in hypothesis describes a mapping between the temporal and spatial power spectrum of
turbulence, which we apply to density fluctuations. We explore the validity of the assumptions underlying Taylor's hypothesis and evaluate its applicability in extracting spatial power spectra of density fluctuations of black hole
accretion flows. Using outputs from the GRMHD code KORAL, we explore models with strong and ordered
magnetic fields (MAD, Magnetically Arrested Disks) as well as weak and disordered
magnetic fields (SANE, Standard and Normal
Evolution). We explore the effects of black hole
spin on the power spectra and characterize their spectral properties as a function of distance from the black hole. The observed power spectra follow a broken power law with two slopes separated by a break frequency. Our analysis shows a decrease in break frequency with increasing radius, with distinct trends between SANE and MAD flows. We also observe the first slope to be steeper for SANE flows and some notable distinctions between prograde and retrograde
spins.
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All authors Pravita Hallur, Lia Medeiros, Pierre Christian, George N. Wong
High Energy Astrophysical Phenomena
Luminous Fast Blue Optical Transients as "Failed" Gravitational-wave Sources: Helium Core$-$Black Hole Mergers Following Delayed Dynamical Instability
Jakub Klencki and Brian D. Metzger
Binaries in which a massive donor
star undergoes an extended ($\gtrsim$ kyr) phase of stable mass transfer onto a black hole (BH) accretor offer a promising channel for creating LIGO gravitational wave sources. However, in many systems the mass transfer terminates prematurely in a dynamical instability at orbital periods of a few days, culminating in the BH plunging into the donor and potentially disrupting and accreting its helium core at highly super-Eddington rates. Combining a suite of binary
evolution models with analytic estimates and population synthesis, we predict the population of luminous transients from delayed dynamical instability (DDI) and attribute them to the "luminous" class of fast blue optical transients (LFBOTs). The initial plunge of the BH into the partially stripped envelope typically ejects $\sim 10M_{\odot}$ of H/He-enriched material at speeds $\sim 10^{2}-10^{3}$ km s$^{-1}$, generating a compact circumstellar medium (CSM) of radius $\lesssim 1000R_{\odot}$ by the time the BH meets and tidally disrupts the HeC. Rapid BH
accretion generates a highly aspherical wind-driven explosion into the environment, powering UV/optical emission via CSM interaction and X-ray reprocessing that rises over a few days to a luminosity $\sim 10^{44}-10^{45}$ erg s$^{-1}$ before fading as the disk spreads outwards and
accretion rate drops. Luminous
radio/sub-mm emission is generated over several months as the jet collides with the slow quasi-spherical binary
outflow, generated by the stable mass transfer preceding DDI, extending to radii $\sim 10^{17}$ cm, in agreement with the inferred CSM environments of LFBOTs. We estimate local rates of DDI merger transients $5-300$ Gpc$^{-3}$ yr$^{-1}$, with a preference for low-
metallicities, in agreement with LFBOT demographics. Taken together, our results support LFBOTs as being luminous signposts of "failed" gravitational wave sources.
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High Energy Astrophysical Phenomena
No Sign of a Magnetar Remnant Following the Kilonova-Producing Long GRB 211211A $\sim 1.7~$Years Later
Genevieve Schroeder, Ben Margalit, Brian D. Metzger et al. (+9 more)
In addition to a $\gamma$-ray burst (GRB), the merger of two
neutron stars may produce a temporarily or indefinitely stable
neutron star remnant with a strong
magnetic field (a "magnetar"). As this magnetar remnant
spins down, it can deposit its rotational energy into the surrounding kilonova ejecta, producing synchrotron emission that peaks in the
radio bands $\sim$months-years after the merger ("boosted kilonova"). The nearby ($z=0.0763$) long-duration GRB 211211A, which has an apparent kilonova counterpart and likely
neutron star merger progenitor, may have produced such a remnant. We observed the location of GRB 211211A at 6 GHz with the NSF's Karl G. Jansky Very Large Array (VLA) spanning $\approx 0.54$-$1.7~$years after the burst. We do not detect any
radio emission, placing strong limits on the energy deposited into the ejecta by any remnant to $\lesssim 4.4 \times 10^{52}~{\rm erg}$. Due to the proximity of the event, we are also able to place limits on a kilonova afterglow that did not receive any additional energy deposition, though it is possible such emission will be suppressed until $\sim 4~{\rm years}$ after the burst, when the kilonova is expected to overtake the forward shock of the GRB. Future observations with the VLA and next-generation
radio facilities will be able to further constrain the magnetar-boosted kilonova and kilonova afterglow scenarios, as well as directly constrain models in the scenario that GRB 211211A was instead produced by a collapsar.
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All authors Genevieve Schroeder, Ben Margalit, Brian D. Metzger, Wen-fai Fong, Benjamin P. Gompertz, Kate D. Alexander, Edo Berger, Tanmoy Laskar, Gavin P. Lamb, Andrew Levan, Charles D. Kilpatrick, Jillian C. Rastinejad
Astrophysics of Galaxies
Elusive Plunges and Heavy Intermediate-mass-ratio Inspirals from Single and Binary Supermassive Black Holes
Lazaros Souvaitzis, Antti Rantala and Thorsten Naab
The most massive
galaxies in the Universe also host the largest supermassive black holes (SMBHs), with masses of $10^9 \: \mathrm{M_{\odot}}$ and above. During their hierarchical assembly, these
galaxies have experienced only a few major mergers at low
redshift, but have accreted many low-mass
galaxies across
cosmic time, possibly hosting intermediate mass black holes (IMBHs). If some of these IMBHs migrate to the
galactic center, they may form compact subsystems around the central SMBH. We investigate the
evolution of such subsystems, consisting of ten $10^5 \: \mathrm{M_{\odot}}$ IMBHs at three different concentrations around a $10^9 \: \mathrm{M_{\odot}}$ SMBH. We evolve these systems both in isolation and in the presence of a companion SMBH, using MSTAR, a regularized integration method including relativistic effects up to post-Newtonian order 3.5PN. Our analysis focuses on gravitational–wave–driven intermediate–mass–ratio inspirals (heavy IMRIs) and direct plunges. We show that perturbations from a secondary SMBH enhance the number of IMBH direct plunges by more than a factor of two, making them the dominant merger channel. These plunges and IMRIs with a central $10^9 \: \mathrm{M_{\odot}}$ SMBH will contribute to SMBH growth but will likely evade detection with future gravitational-wave interferometers and
pulsar timing arrays (PTAs). However, for
galaxies with lower–mass SMBHs ($M_\bullet \lesssim 10^8 \:\mathrm{M_{\odot}}$), heavy IMRIs will be detectable with the
Laser Interferometer Space
Antenna (LISA) and can provide direct observational constraints on the existence of IMBHs, while the more numerous plunges will still remain hidden.
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High Energy Astrophysical Phenomena · Cross-listed from gr-qc
The Gravitational Wave Memory from Binary Neutron Star Mergers
Jamie Bamber, Antonios Tsokaros, Milton Ruiz et al. (+4 more)
The gravitational wave signal produced by the merger of two compact objects includes both an oscillatory transient and a non-oscillatory part, the so-called
memory effect. This produces a permanent displacement of test masses and has not yet been measured. We use general relativistic magnetohydrodynamic simulations, including
neutrinos, with several representative viable equations of state, to quantify–for the first time–the effects of the
neutron star magnetic field,
neutrino emission, and the ejected mass on the linear and nonlinear displacement
memory in binary
neutron star mergers. We find that the additional contributions due to the emission of electromagnetic radiation,
neutrinos and baryonic ejecta can be ~15% of the total
memory for moderate
magnetic fields and up to ~50% for extreme
magnetic fields. The
memory is most affected by changes in the equation of state, the binary mass, and the
magnetic field. In particular, for moderate premerger field strengths, the dominant impact of the electromagnetic field is the change in the gravitational wave luminosity, and the associated gravitational wave null
memory, due to the unstable growth of the
magnetic field and the resulting redistribution of angular momentum it induces in the remnant. While the direct electromagnetic contribution to the null
memory is additive, the change in the gravitational wave null
memory can–in some cases–result in the total
memory being smaller than that from the corresponding nonmagnetized binary. Furthermore, in contrast to binary black hole mergers, the growth of the
memory in binary
neutron star mergers is extended due to the long emission timescale of electromagnetic fields,
neutrinos, and ejecta. These results necessitate the consideration of the
magnetic field, as well as the equation of state, for accurate parameter estimation in future analyses of gravitational wave
memory data.
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All authors Jamie Bamber, Antonios Tsokaros, Milton Ruiz, Stuart L. Shapiro, Marc Favata, Matthew Karlson, Fabrizio Venturi Piñas
Astrophysics of Galaxies
Catalog of Mock Stellar Streams in Milky Way-Like Galaxies
Colin Holm-Hansen, Yingtian Chen and Oleg Y. Gnedin
Dynamically cold
stellar streams from tidally dissolved globular clusters (GCs) serve as excellent tools to measure the
Galactic mass distribution and show promise to probe the nature of dark matter. For successful application of these tools to observations, it is essential to have models of
stellar stream properties on the
Galactic scale. To this end we produce a mock catalog of
stellar streams in four Milky Way-mass
galaxies from cosmological simulations. We build the catalog with three main components: a model for the formation and disruption of globular clusters based on cosmological simulations, time-dependent potentials constructed with basis function expansions for integrating stream orbits, and an improved particle-spray
algorithm for efficient generation of
stellar streams. We generate mock photometry for
Gaia, LSST, and Roman, and find that the latter two surveys will increase the number of observable
stars in GC
stellar streams by several orders of magnitude, with LSST alone being able to observe 1000 or more
stars in 40-100 streams beyond the
stellar disk. In addition, we find that the observable widths and lengths of mock streams as a function of galactocentric radius are well described by power-laws with slopes of $-1.8$ and $-2$ for streams beyond 10~kpc. Our full catalog, containing stream populations across four different
galaxy realizations, is publicly available and can be used to study stream population statistics and to calibrate models which use
stellar streams to understand our
Galaxy.
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Cosmology and Nongalactic Astrophysics
Anchoring the Universe with Characteristic Redshifts using Raychaudhuri Equation Informed Reconstruction Algorithm (REIRA)
Shibendu Gupta Choudhury, Purba Mukherjee and Anjan Ananda Sen
We study the robustness and physical implications of a set of characteristic
redshifts that capture key features of the late-time Universe. Using both model-independent reconstructions as well as different dark energy (DE) parameterizations, we show that these
redshifts remain stable across cosmological models and reconstruction
algorithm, making them reliable
geometric anchors of the expansion history. Moreover, the Alcock-Paczyński corrections at these
redshift anchors are found to be unity with high statistical significance, making them natural isotropy points in the comoving distance-
redshift relation. We also find that certain
redshifts anchors $(z < 1)$ coincide with epochs where strong deviations from the Planck $\Lambda$CDM baseline are apparent irrespective of DE parametrisation like CPL or reconstruction
algorithm, indicating their potential as probes of new physics in cosmological
evolution. Finally, we demonstrate, for the first time, that a Raychaudhuri Equation Informed Reconstruction
Algorithm, substantially enhances the precision of the inferred distance measures and the Hubble expansion rate as well as results tighter constraints in the DE parameter space. These results demonstrate that combining
geometric reconstruction with physics-informed kinematic information offers a powerful and consistent
algorithm to probe new physics in the late-time dynamics of our Universe.
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Solar and Stellar Astrophysics
JWST Observations of SN 2024ggi II: NIRSpec Spectroscopy and CO Modeling at 285 and 385 Days Past the Explosion
T. Mera, C. Ashall, P. Hoeflich et al. (+20 more)
We present James Webb Space
Telescope (JWST) NIRSpec observations of SN~2024ggi, spanning wavelengths of 1.7–5.5 micron at +285.51 and +385.27 days post-explosion. These nebular spectra are dominated by asymmetric emission lines from atomic species including H, Ca, Ar, C, Mg, Ni, Co, and Fe, indicative of an aspherical explosion. The other strong features are molecular CO vibrational bands from the fundamental and first overtone. We introduce a novel, data-driven approach using non-LTE 3D radiative transfer simulations to model the CO emission with high fidelity. This method enables us to constrain the three-dimensional CO distribution and its radial temperature structure. CO formation is found to occur prior to day +285, with subsequent
evolution characterized by progressive evaporation. The CO mass decreases from approximately 8.7 to 1.3*E-3 Mo, while the average temperature drops from about 2900 K to 2500 K. Concurrently, the CO distribution transitions from nearly homogeneous to highly clumped (density contrast increasing from fc=1.2 to 2). The minimum velocity of the CO-emitting region remains nearly constant (v1 = 1200 to 1100 km/s), significantly above the receding photosphere velocity (v(ph) = 500 km/s), suggesting the photosphere resides within Si-rich layers. However, the temperature profile indicates that only a narrow zone reaches the conditions necessary for SiO formation. Due to a lack of observational constraints, SiO clumping is not modeled, and thus, synthetic SiO profiles for mass estimates are not highlighted. We discuss the implications of these findings for
dust formation processes in SN~2024ggi.
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All authors T. Mera, C. Ashall, P. Hoeflich, K. Medler, M. Shahbandeh, C. R. Burns, E. Baron, J. M. DerKacy, N. Morrell, J. Lu, J. T. Hinkle, P. A. Mazzali, E. Fereidouni, C. M. Pfeffer, S. Shiber, T. Temim, L. Galbany, D. A. Coulter, L. Ferrari, W. B. Hoogendam, E. Y. Hsiao, M. M. Phillips, B. J. Shappee
Cosmology and Nongalactic Astrophysics
Deep uGMRT observations for enhanced calibration of 21 cm arrays – I. First image and source catalogue
Khandakar Md Asif Elahi, Samir Choudhuri, Nirupam Roy et al. (+3 more)
Radio-interferometric arrays require very precise calibration to detect the Epoch of Reionization 21-cm signal. A remarkably complete and accurate sky model is therefore needed in the patches of the sky used to perform the calibration. Instruments such as HERA, which use a redundant calibration strategy, also require a reference sky model to fix degenerate gain solutions. We have carried out a deep (20 hours) observation using the upgraded GMRT to make a high-fidelity sky model of one of the HERA calibration fields GLEAM 02H (J0200$-$3053). Here, we present the results from a $16.7\,\rm{MHz}$ bandwidth data centred at $147.4\,\rm{MHz}$. Using multiple GMRT pointings, we have made a $6.9^\circ\times6.9^\circ$ mosaic, which yields a median rms of $3.9^{+3.7}_{-1.4}\,{\rm mJy/beam}$ that reduces to $\sim2\,{\rm mJy/beam}$ at source-free regions. In the overlapping patch, this rms is deeper than the GLEAM catalogue, which is used for HERA calibration. We produce a catalogue of $640$ sources ($26\%$ extended) in the flux range $0.01-19.08\,{\rm Jy}$. The catalogue has a sub-arcsec positional accuracy, and the estimated fluxes are consistent with existing catalogues. The differential source counts are found to be deeper than GLEAM and consistent with LoTSS. Preliminary simulations of the sky models from GLEAM and our catalogue show $\sim 10-25\%$ difference in the visibility amplitude, with relatively small phase difference ($\approx 2^\circ$). Future work is planned for larger survey areas and wider bandwidth to reduce the rms and measure the in-band source spectral indices, which are expected to enhance the fidelity of the HERA calibration model.
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All authors Khandakar Md Asif Elahi, Samir Choudhuri, Nirupam Roy, Md Rashid, Philip Bull, Dharam Vir Lal
High Energy Astrophysical Phenomena
SN 2021lwz: Another Exotic Luminous and Fast Evolving Optical Stripped Envelope Supernova ?
F. Poidevin, S. L. West, C. M. B. Omand et al. (+25 more)
Current large-scale, high-cadence surveys, such as the ZTF, provide detections of new and rare types of transients and
supernovae whose physical origins are not well understood. We investigate the nature of SN 2021lwz at a
redshift $z=0.065$, an overluminous
supernova (SN) of absolute magnitude, $M_{g} \sim -20.1$ AB, falling in the lower range of superluminous
supernovae (SLSNe) luminosities, and discovered in a faint
dwarf galaxy with an absolute magnitude of $M_{g} \simeq -14.5$ AB. SN 2021lwz is studied using optical spectroscopy, photometry and imaging linear polarimetry obtained during several follow-up campaigns. All the data are used to analyse and model the
evolution of the explosion. Comparisons with other SNe of well known or rarer types are investigated. SN 2021lwz belongs to the rare class of rapidly evolving transients. The bolometric light curve rises in about $7$ days to a peak luminosity of about $5 \times 10^{43}$ erg/s, at a rate of 0.2 mag day$^{-1}$ close to the peak. Spectroscopy modelling reveals more similarities with a normal Type Ic-like SN than with a SLSN before peak, showing slightly broadened lines after peak. Light curve modelling shows that the Arnett model of the bolometric light curve using a radioactive source ($^{56}$ Ni) is not able to reasonably explain the light curve
evolution. A magnetar model seems more appropriate, suggesting that the explosion of low ejecta mass ($M_{\rm ej} \sim 0.24 ~M_\odot$) took place in a low mass ($M \sim 10^{6.66}~M_\odot$)
dwarf galaxy of specific
star-formation rate about ten times larger than typical
star-forming
galaxies. In conclusion SN 2021lwz is an uncommon transient showing many similarities with several classes of transients, and with rare transients. It may be an interesting example pointing on how differences in ejecta mass and engine parameters could produce a wide range of engine-driven SESNe.
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All authors F. Poidevin, S. L. West, C. M. B. Omand, R. Könyves-Tóth, S. Schulze, L. Yan, T. Kangas, I. Pérez-Fournon, S. Geier, J. Sollerman, P. J. Pessi, C. M. Gutiérrez, T.-W. Chen, K-Ryan Hinds, R. Marques-Chaves, R. Shirley, C. Jimenez Angel, R. Lunnan, D. A. Perley, N. Sarin, Y. Yao, R. Dekany, J. Purdum, A. Wold, R. R. Laher, M. J. Graham, M. M. Kasliwal, T. Jegou Du Laz
Astrophysics of Galaxies
Galaxy Underdensities Host the Clearest IGM Ly$\alpha$ Transmission and Indicate Anisotropic Reionization
Yongda Zhu, George D. Becker, Anson D'Aloisio et al. (+6 more)
How
galaxies drive reionization and what governs its geometry remain fundamental questions. We present JWST/NIRCam wide-field slitless spectroscopy (WFSS) observations toward two of the most Ly$\alpha$-transmissive QSO sightlines near the end of reionization. We find that regions at $z \sim 5.7$ along both sightlines previously found to be low-density in Ly$\alpha$ emitters are also underdense in [O III] emitters, with densities less than half the
cosmic mean. Other transmissive regions, however, are found to coincide with average-density environments, indicating that multiple pathways may produce high IGM transmission. For the first time, we measure the two-dimensional cross-correlation between IGM transmission and
galaxy positions, revealing evidence for anisotropic ionization geometry. Specifically, we detect enhanced transmission at transverse distances of $\Delta r \sim 0.8$ times the mean free path, consistent with ionizing
photons escaping preferentially along large-scale structures that are aligned with, but offset from, the line of sight. This anisotropic escape may contribute to the observed patchiness of reionization and challenges the assumption of isotropic ionized bubble growth in current models.
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All authors Yongda Zhu, George D. Becker, Anson D'Aloisio, Ryan Endsley, Nakul Gangolli, Christopher Cain, Charlotte A. Mason, Seyedazim Hashemi, Hui Hong
Cosmology and Nongalactic Astrophysics
Andrea Rubiola, Matteo Zennaro, Carlos García-García et al. (+2 more)
We present constraints on the amplitude of matter fluctuations from the clustering of
galaxies and their cross-correlation with the gravitational
lensing convergence of the
cosmic microwave background (CMB), focusing on low
redshifts ($z\lesssim0.3$), where potential deviations from a perfect cosmological constant dominating the growth of structure could be more prominent. Specifically, we make use of data from the 2MASS photometric survey (\tmpz) and the \wisc
galaxy survey, in combination with CMB
lensing data from \planck. Using a hybrid effective field theory (HEFT) approach to model
galaxy bias we obtain constraints on the combination $S_8=\sigma_8\sqrt{\Omega_m/0.3}$, where $\sigma_8$ is the amplitude of matter fluctuations, and $\Omega_m$ is the non-relativistic matter fraction. Using a prior on $\Omega_m$ based on the
baryon acoustic oscillation measurements of DESI, we find $S_8=0.79\pm0.06$, in reasonable agreement with CMB constraints. We also find that, in the absence of this prior, the data favours a value of $\Omega_m=0.245\pm0.024$, that is 2.8$\sigma$ lower than \planck. This result is driven by the broadband shape of the
galaxy auto-correlation, and may be affected by theoretical uncertainties in the HEFT power spectrum templates. We further reconstruct the low-
redshift growth history, finding it to be compatible with the \planck predictions, as well as existing constraints from
lensing tomography. Finally, we study our constraints on the HEFT bias parameters of the
galaxy samples studied, finding them to be in reasonable agreement with coevolution predictions.
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All authors Andrea Rubiola, Matteo Zennaro, Carlos García-García, David Alonso, Raul Angulo
High Energy Astrophysical Phenomena
Direct observation of the X-ray counterpart of the H{\alpha} filaments and of the sloshing spiral in the Perseus galaxy cluster
Adrien Picquenot, Fabio Acero, Valeria Olivares et al. (+2 more)
Deep Chandra observations of the Perseus
galaxy cluster have allowed for the discovery of X-ray counterparts to the H{\alpha} filamentary structures and of a sloshing spiral. However, both components are extremely faint, and their study is largely hindered by the volume-filling hot intracluster medium (ICM). Using the Poisson General Morphological Component Analysis (pGMCA)
algorithm, a blind source separation method adapted for Poissonian statistics, we were able to extract detailed, clean morphological maps of these components. We then introduced a template fitting method to investigate their spectral characteristics. We report the first direct observation of about 1.35 keV low-energy emission from the sloshing spiral, and produce the most detailed and unpolluted map of the X-rays filaments thus far obtained.
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All authors Adrien Picquenot, Fabio Acero, Valeria Olivares, Michela Negro, Gabriel W. Pratt
Instrumentation and Methods for Astrophysics
Hierarchical Progressive Survey (HiPS) format: moving from visualisation to scientific analysis
Fabrizio Giordano, Yago Ascasibar, Luca Cortese et al. (+2 more)
Context. In the current era of multi-wavelength and multi-messenger astronomy, international organisations are actively working on the definition of new standards for the publication of astronomical data, and substantial effort is devoted to make them available through public archives. Aims. We present a set of tools that allow user-friendly access and basic scientific analysis of observations in Hierarchical Progressive Survey (HiPS) format, and we use them to gauge the quality of representative skymaps at ultraviolet, optical, and infrared wavelengths. Methods. We apply a fully-automatic procedure to derive aperture photometry in 10 different bands for the 323 nearby
galaxies in the Herschel Reference Sample (HRS), and compare its results with the rigorous analyses involving specialised knowledge and human intervention carried out by the HRS team. Results. Our experiment shows that 9 of the 10 skymaps considered preserve the original quality of the data, and the photometric fluxes returned by our pipeline are consistent with the HRS measurements within a few per cent. In the case of Herschel PACS maps at 100 {\mu}m, we uncovered a systematic error that we ascribe to an inconsistent combination of data products with different spatial resolution. For the remaining skymaps, the estimated statistical uncertainties provide a realistic indication of the differences with respect to the HRS catalogue. Conclusions. In principle, the currently available HiPS skymaps in Flexible Image Transport System (FITS) format allow to carry out broadband photometric analyses with an accuracy of the order of a few percent, but some level human intervention is still required. In addition to assessing data quality, we also propose a series of recommendations to realise the full potential of the HiPS format for the scientific analysis of large astronomical data sets.
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All authors Fabrizio Giordano, Yago Ascasibar, Luca Cortese, Ivan Valtchanov, Bruno Merín
Cosmology and Nongalactic Astrophysics
Extending CSST Emulator to post-DESI era
Zhao Chen and Yu Yu
The recent DESI BAO measurements have revealed a potential deviation from a cosmological constant, suggesting a dynamic nature of dark energy. To rigorously test this result, complementary probes such as weak gravitational
lensing are crucial, demanding highly accurate and efficient predictions of the nonlinear matter power spectrum within the $w_0w_a$CDM framework. However, most existing emulators fail to cover the full parameter posterior from DESI DR2+CMB constraints in the $w_0\mbox{-}w_a$ plane. In this work, we extend the spectral equivalence method outlined in Casarini et al. 2016 to use auxiliary $w_0w_a$CDM models for approximating the power spectrum of a target $w_0w_a$CDM cosmology, moving beyond the previous use of $w$CDM auxiliaries. Incorporating this enhanced module, the extended CSST Emulator achieves a prediction accuracy of $\leq1\%$ over the $1\sigma$ confidence region from DESI DR2+CMB constraints for $z\leq3$, with a mild degradation in accuracy outside this posterior region. This performance is rigorously validated by additional simulations of dynamic dark energy cosmologies. The emulator's applicable parameter space has been generalized to fully encompass the $2\sigma$ region, greatly enhancing its utility for cosmological analysis in the post-DESI era.
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Astrophysics of Galaxies
What is the contribution of gravitational infall on the mass assembly of star-forming clouds? A case study in a numerical simulation of the interstellar medium
Noé Brucy, Enrique Vázquez-Semadeni, Tine Colman et al. (+2 more)
Star formation in
galaxies is a complex phenomenon occurring on a very wide range of scales, and molecular clouds are at the heart of this process. The formation of these structures and the subsequent collapse of the gas within them to form new
stars remain unresolved scientific questions. In particular, the role and importance of
gravity at between the disk scale height and prestellar cores (100 to 0.01 pc) are still topics of debate. In this work, we conduct a case study examining the mass assembly and
evolution of a
giant molecular cloud complex in a numerical stratified-box simulation of the interstellar medium with photo-ionizing and
supernova driving and resolving down to scales $\gtrsim 1$ pc and densities up to $10^3$ cm$^{-3}$. By introducing tracer particles to precisely track the forces acting on the gas during its
evolution towards and within the clouds, we are able to quantify how much of the mass inflow is driven by the self-
gravity of the gas and the
gravity from the
stellar disk. We find that up to 20% of the gas is
gravity-driven at a scale of 100 pc, contributing 10% of the inflow from the warm to the cold phase and 20% from the cold phase to the individual molecular clouds, reaching up to 45% inside the molecular gas, at densities $\gtrsim 400$ cm$^{-3}$. However, at the 100 pc scale, the contribution of
gravity-driven gas on the linewidth is negligible. We conclude that the bulk of the gas motions assembling the clouds in our simulation are caused by the
supernova-driven supersonic
turbulence, which results in locally convergent flows, with a small contribution from the
stellar gravitational potential.
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All authors Noé Brucy, Enrique Vázquez-Semadeni, Tine Colman, Jérémy Fensch, Ralf S. Klessen
Cosmology and Nongalactic Astrophysics
Generalized Distributions of Host Dispersion Measures in the Fast Radio Burst Cosmology
Jing-Yi Jia, Da-Chun Qiang, Lin-Yu Li et al. (+1 more)
Fast
radio bursts (FRBs) can provide a measure of the Hubble constant $H_0$ that is independent of the constraints set by the
cosmic microwave background (CMB) and the type Ia
supernovae (SNIa), thereby arbitrating the Hubble tension. In the literature, the methodology proposed by Macquart et al. has been widely used, in which the contributions to the dispersion measure (DM) from the intergalactic medium (IGM, $\rm DM_{IGM}$) and the host
galaxy ($\rm DM_{host}$) are described by probability distribution functions. Within the Macquart et al. methodology, it has been found that the parameter $F$, which quantifies the strength of the
baryon feedback in
galaxies, must be bound by an artificially narrow prior to result in a Hubble constant $H_0$ that is consistent with the ones derived from the CMB and SNIa studies. A recent study using ${\cal O}(100)$ localized FRBs found that this also causes the fraction of
baryon mass in the IGM, $f_{\rm IGM}$, to approach its upper bound of 1. In the present work, using 125 localized FRBs, we find an unusually low $H_0$ when using a model with a loose prior on $F$. This model is in fact strongly preferred to the model with the narrow prior when considering the
Bayesian evidence and the Akaike and
Bayesian information criteria. Instead of modifying $\sigma_\Delta=Fz^{-0.5}$ in the distribution of $\rm DM_{IGM}$, we explore an alternative method of resolving the tension by generalizing the distribution of $\rm DM_{host}$ with varying location and scale parameters $\ell$ and $e^\mu$, respectively. We find that $H_0$ can be well consistent with the ones of Planck 2018 and SH0ES for all the models considered in this work, while these generalized models are all strongly preferred to the model with a narrow prior on $F$. Our findings indicate that more realistic distributions of $\rm DM_{host}$ could be the key to using FRBs as an independent measure of $H_0$.
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All authors Jing-Yi Jia, Da-Chun Qiang, Lin-Yu Li, Hao Wei
Cosmology and Nongalactic Astrophysics
The choice of Planck CMB likelihood in cosmological analyses
Hidde Jense, Marc Viña, Erminia Calabrese et al. (+1 more)
We compare cosmological parameters from different Planck sky maps and likelihood pipelines, assessing robustness of cosmological results with respect to the choice of the latest Planck maps-likelihood combination. We show that, for the Planck multipole range retained in combination with ground-based observations, different products give very similar cosmological solutions; small remaining differences are reduced by the addition of other CMB
datasets to Planck. In particular, constraints on extended cosmological models benefit from the addition of small-scale power from ground-based experiments and are completely insensitive to the choice of Planck maps and likelihood. For this work we derive and release a nuisance-marginalized
dataset and CamSpec-NPIPE-lite likelihood for the Planck NPIPE data injected into the CamSpec likelihood - which are usually used to obtain the reference Planck PR4 cosmology. Using the extracted CMB spectra we show that the additional constraining power for cosmology is coming from polarization at all scales and from temperature at multipoles above 1500 when going from PR3 to PR4. We also show that full marginalization over the CamSpec foreground nuisance parameters can impact parameter inference and model selections when truncating some scales; our new likelihood enables correct combinations with other CMB
datasets.
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All authors Hidde Jense, Marc Viña, Erminia Calabrese, J. Colin Hill
Cosmology and Nongalactic Astrophysics
Safely simplifying redshift drift computations in inhomogeneous cosmologies: Insights from LTB Swiss-cheese models
David Rønne Sallingboe and Sofie Marie Koksbang
One of the most important discoveries in cosmology is the accelerated expansion of the Universe. Yet, the accelerated expansion has only ever been measured indirectly.
Redshift drift offers a direct observational probe of the Universe's expansion history, with its sign revealing whether there has been acceleration or deceleration between source and observer. Its detection will mark a major milestone in cosmology, offering the first direct measurement of an evolving expansion rate. Given its epistemic importance, it is essential to understand how its measurements can be biased. One possibility of bias comes from cosmological structures. However, theoretical estimates of such effects are difficult to obtain because computing
redshift drift in general inhomogeneous cosmologies is computationally demanding, requiring the solution of 24 coupled ordinary differential equations. In this work, we use Lemaitre-Tolman-Bondi Swiss-cheese models to show that only the two dominant contributions are needed to achieve percent-level accuracy up to $z = 1$. This allows the reduction of the full system of 24 ODEs to the standard null geodesic equations, significantly simplifying the calculation. \newline\indent Although our analysis is based on idealized Swiss-cheese models with spherical structures, we expect that similar simplifications apply to more complex scenarios, including cosmological N-body simulations. Our analysis thus underpins a practical and robust framework for efficient
redshift drift computations applicable to a wider range of inhomogeneous cosmologies.
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Earth and Planetary Astrophysics · Cross-listed from physics.geo-ph
Interactions between syn-rift magmatism and tectonic extension at intermediate rifted margins
Peng Yang, Marta Perez-Gussinye, Shaowen Liu et al. (+2 more)
Intermediate rifted margins exhibit neither seaward dipping reflectors nor exhumed mantle at the continent-ocean transition (COT). Instead, they transition into normal-thickness, magmatic Penrose-type oceanic crust, and thus diverge from the classic magma-rich and magma-poor end-member models. However, several intermediate margins, such as the South China Sea (SCS), display detachment faulting similar to magma-poor margins and magmatic underplating typical of magma-rich ones. How tectonics and magmatism interact in these intermediate environments is poorly understood. Here we use 2D numerical models to demonstrate that the elevated initial geotherm inherited from prior plate subduction in the SCS explains several key observations: an early phase of wide rifting, subsequent localization onto core complexes with substantial footwall magmatic intrusions, and eventual formation of normal igneous oceanic crust at break-up. Thermal weakening caused by syn-rift footwall magmatic intrusions facilitates lower crustal ductile flow, promoting the development of rolling-hinge type detachment faults and exhumation of core complexes. These structures are associated with accelerated tectonic subsidence, which is later moderated by detachment-related doming, as observed in the SCS. Normal-thickness oceanic crust occurs after break-up, even under ultra-slow extension rates used in our simulations, highlighting the importance of inheritance in determining margin architecture, the spatio-temporal distribution of syn-rift magmatism, and the nature of the COT. This behavior contrasts sharply with magma-poor margins, where a cooler lithosphere and similar ultra-slow extension produce no syn-rift magmatism, leading instead to crustal embrittlement, mantle serpentinization and exhumation at the COT.
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All authors Peng Yang, Marta Perez-Gussinye, Shaowen Liu, Javier Garcia-Pintado, Gudipati RaghuRam