Cosmology and Nongalactic Astrophysics
Stars Would Remember a Recent Gravitational Transition: Testing G-step Resolutions of the Hubble Tension with Red Dwarfs
Jeremy Sakstein and Harry Desmond
We test the hypothesis that Newton's gravitational constant underwent a rapid transition approximately $73$-$130\,{\rm Myr}$ ago, as proposed in some resolutions of the Hubble tension. Fully convective red dwarf
stars with masses below $\sim0.35\,M_\odot$ have thermal timescales comparable to the proposed transition look-back times, so an appreciable present-day
memory can remain. We show that a rapid step in $G$ induces measurable changes in their radii and confront these predictions with mass-radius measurements of eight red dwarfs in detached eclipsing binaries. We find that the $G$-step models proposed to resolve the Hubble tension, corresponding to a $4\%$ change in $G$ at a look-back time of $73\,{\rm Myr}$ and an $11\%$ change at $130\,{\rm Myr}$, are excluded at significances of $3.1\sigma$ and $4.0\sigma$, respectively.
Read the full abstract ▾
High Energy Astrophysical Phenomena
A concordance model of neutron star kicks
Cheyanne Shariat, Kareem El-Badry and Smadar Naoz
Neutron stars (NSs) receive natal kicks during
supernovae that affect their survival in binaries and motion through the
Galaxy. The global distribution of these kick velocities across the NS population remains uncertain. Here, we combine the orbital properties and birth rates of Gaia NS and Be+NS binaries with velocity constraints from young isolated
pulsars to construct a concordance model of NS natal kicks. We find that all three populations can be jointly described by a shared bimodal kick distribution. The low-velocity component follows a lognormal distribution with $\mu_{\ln v}=1.87^{+0.65}_{-0.53}$ and $\sigma_{\ln v}=0.55^{+0.85}_{-0.44}$, corresponding to a median speed of $6.5^{+5.9}_{-2.7}~{\rm km~s^{-1}}$. The high-velocity component is consistent with the distribution inferred from young
pulsars, which peaks near $200~{\rm km~s^{-1}}$. The low-velocity component contributes only $\sim10\%$ of all NS births, but produces most Gaia NS binaries and roughly half of Be+NS binaries. The same model predicts systemic recoil velocities consistent with the observed kinematics of Gaia NSs, Be+NS binaries, and NS low-mass X-ray binaries. For Gaia NSs, whose formation history remains unknown, we use this kick distribution to constrain their progenitors. We favor pre-
supernova binaries containing intermediate-mass stripped
stars with $\sim1~{\rm M_\odot}$ companions in au-scale orbits, and predict $\sim300$ such binaries in the Milky Way today, $\sim40$ in the LMC, and $\sim30$ in the SMC. Finally, we consider the implications of these kicks for NSs in hierarchical triples. We find that 2-10$\%$ of Gaia NS triples and 3-23$\%$ of Be+NS triples retain their tertiary after the
supernova. Overall, our results suggest that a shared natal kick law can account for isolated
pulsars and surviving NS binaries, where most NSs receive large kicks and low kicks are common among surviving binaries.
Read the full abstract ▾
High Energy Astrophysical Phenomena
A Unified Multi-Band Secular Framework for the Hierarchical Triple PSR J0435+3233 System
Achamveedu Gopakumar, Vidit Singh, Abhimanyu Susobhanan et al. (+9 more)
The millisecond
pulsar PSR J0435+3233, discovered by FAST, exhibits an unusually large apparent
spin-down rate, potentially reflecting line-of-sight acceleration from a distant companion. Recent investigations reveal a hierarchical triple consisting of an inner
pulsar-helium white dwarf binary with an orbital period of ~8 days, orbited by a G-type subgiant tertiary on an eccentric ~74 yr orbit. The current timing description admits two distinct geometrical solutions. We develop a singly averaged (SA) formulation that averages over the inner orbit while retaining the instantaneous phase of the eccentric outer orbit, thereby capturing the time-dependent quadrupolar perturbations induced by the tertiary. We show how this physical three-body description can be incorporated naturally into
pulsar-timing analyses and use it to forward-propagate the two currently viable configurations, Tv1 and Tv2, to forecast when their timing signatures become distinguishable with FAST. The SA
evolution predicts that the two configurations will become distinguishable in the coming years, with the effective projected semi-major axis, $x_{1,\mathrm{eff}}$, providing the earliest discriminating observable. We further extend the framework to predict the tertiary's spectroscopic radial-velocity and astrometric
evolution, linking FAST timing with LAMOST time-domain spectroscopy and Gaia astrometry. This multi-band framework has the potential to establish PSR J0435+3233 as an exceptionally well-constrained laboratory for three-body dynamics, compact-binary and stellar
evolution, and gravitational physics.
Read the full abstract ▾
All authors Achamveedu Gopakumar, Vidit Singh, Abhimanyu Susobhanan, Mauri J. Valtonen, Sayantan Bhattacharya, Di Li, Hong-Liang Yan, Jianping Yuan, Na Wang, Pei Wang, Qingdong Wu, De Zhao
Astrophysics of Galaxies
The Merian Survey: A Statistical Census of Bright Satellites of Sub-Milky Way-Mass Galaxies
Lucas S. Mandacarú Guerra, Jiaxuan Li, Yue Pan et al. (+9 more)
Satellite populations provide sensitive tests of the
galaxy-
halo connection, but studies have largely focused on Milky Way (MW)-mass host
galaxies or a small number of nearby dwarf
galaxy hosts. Here we present a statistical census of bright,
star-forming satellite
galaxies around sub-MW-mass hosts using the first data release of the Merian Survey. Our sample consists of 357 hosts with stellar mass $10^{9.5}<M_{\star,\text{host}}<10^{10.5} \ \text{M}_\odot$ at
redshifts $0.07<z<0.09$, all selected to be central
galaxies. Merian's medium-band imaging isolates H$\alpha$ and [O iii] emission lines for
galaxies in this
redshift range, enabling efficient selection of
star-forming satellites down to $M_{\star,\text{sat}}\gtrsim 10^{7.5} \,\text{M}_\odot$. We identify 471 satellite candidates within the projected virial radii of these hosts. After statistically subtracting the contribution from foreground and background
galaxies, we find $148\pm 7$ satellite candidates associated with the host sample. We find that $\mathord{\sim} 60\%$ of hosts have $N_{\rm sat}< 1$ massive satellites within their virial radii, $\mathord{\sim} 22\%$ have $1\leq N_{\rm sat}< 2$, $\mathord{\sim} 10\%$ have $2\leq N_{\rm sat}< 3$, and $\mathord{\sim} 8\%$ have $N_{\rm sat} > 3$. Satellite abundance increases with host stellar mass across the sub-MW regime, extending the observed trend from dwarf to MW-mass
galaxies and broadly agreeing with predictions from the TNG50 simulation. The radial distribution of satellites around sub-MW-mass hosts is similar to that around MW-mass hosts and broadly consistent with TNG50. Together, these results extend our empirical view of satellite populations across the previously sparsely sampled transition between dwarf and MW-mass hosts.
Read the full abstract ▾
All authors Lucas S. Mandacarú Guerra, Jiaxuan Li, Yue Pan, Jenny E. Greene, Shany Danieli, Joy Bhattacharyya, Alyson M. Brooks, Song Huang, Alexie Leauthaud, Yifei Luo, Annika H. G. Peter, Conghao Zhou
Earth and Planetary Astrophysics
The Nearest, Brightest Debris Disk Host Stars: Updated Photosphere Models and Dust Properties for Stars with Saturated 2MASS Photometry
Inbok Yea, Sarah Dodson-Robinson, Cesar Julian Bustos Sanchez et al. (+1 more)
To discover and characterize debris disks, one must obtain high-quality photometry in order to accurately fit photosphere models for the host
stars. Since the $K$ band always falls on the Rayleigh-Jeans side of a
star's spectral energy distribution (SED), its reliability is particularly important for uncovering mid-infrared excess emission from dust. While Two Micron All Sky Survey (2MASS) photometry is the near-infrared
benchmark for most
stars that host debris disks discovered by Spitzer and the Wide Field Infrared Survey Explorer (WISE), the brightest
stars ($K_s < 5$) saturated the 2MASS detectors. To accurately model debris disks that orbit the nearest, brightest
stars, we construct new photosphere models by replacing saturated 2MASS data with $JHK$ photometry from the NASA Catalog of Infrared Observations, archival $R_C I_C$ photometry, and saturation-corrected WISE W1 photometry. We estimate the dust temperature and minimum distance from the
star by fitting blackbody and modified blackbody models to infrared photometry from WISE, Spitzer, and Herschel. Our models allow us to identify disks that subtend large angles on the sky; these disks are candidates for follow-up with ground-based angular differential imaging, the Space
Telescope Imaging Spectrograph (STIS) on the Hubble Space
Telescope (HST), and NIRCam on JWST. Finally, we find that the disk surrounding $\gamma$~Tri likely has warm dust that could be resolvable with JWST's MIRI instrument at $23$ or $25.5 \micron$. Multiwavelength observations provide
benchmarks for collisional cascade models and may reveal
planet–disk interactions.
Read the full abstract ▾
All authors Inbok Yea, Sarah Dodson-Robinson, Cesar Julian Bustos Sanchez, John E. Gizis
Cosmology and Nongalactic Astrophysics
Baryonic Imprints on DM Halos: characterizing the full concentration-mass probability distribution with CAMELS
Elisa J. Gao and Dhayaa Anbajagane
The
halo concentration, which represents the distribution of matter within a
halo, is a vital tool for modeling the matter distribution on scales ranging from megaparsecs to sub-kiloparsecs. While significant progress has been made on connecting the impact of astrophysics on the mean concentration as a function of
halo mass, the same connection to higher moments of the concentration distribution remains far less explored. We employ the IllustrisTNG runs in the CAMELS simulation suite to simultaneously quantify the astrophysics and cosmology dependence of the first four moments of the concentration-mass relation; the mean, the scatter, the skewness, and the kurtosis. We use normalizing flows to model the concentration distribution as a function of
halo mass,
redshift, and six cosmological/astrophysical parameters. We focus on the mass range $M_{\rm vir} \in [10^{11}, 10^{14.5}] M_{\odot}/h$, and the
redshift range $z \in [0, 1]$. All higher-order moments exhibit a mass-dependent sensitivity to both astrophysics and cosmology. The behavior in dark matter-only simulations follows the known effects of active mergers and of tidal stripping in smaller
halos. Once
galaxy formation is included, the scatter shows non-monotonic behavior at the Milky Way (MW) mass-scale, and the amplitude of this behavior is strongly influenced by the baryon fraction and
supernovae (SNe) feedback parameters. The skewness has a large sensitivity to the baryon fraction as well and is mostly insensitive to the other parameters, while the kurtosis follows the behavior set by the skewness. Results for the ASTRID simulation suite show similar behavior as that of IllustrisTNG. The cosmology and astrophysics dependence of these higher-order moments impact analyses that are sensitive to the full distribution of the concentration-mass relation, particularly for
halos at/below the MW mass scale.
Read the full abstract ▾
High Energy Astrophysical Phenomena
Polarimetry of Black Hole Spin and Axisymmetric Emission Geometry
Vadim Bernshteyn, Daniel C. M. Palumbo, Dominic Chang et al. (+1 more)
The Event Horizon
Telescope array has measured the average polarimetric spiral morphology of black hole
accretion disks using the so-called “$\beta_2$” coefficient. This measurement is dominated by the weakly lensed, direct ($n=0$, counting
photon half-orbits) image of the disk, providing insight into
magnetic field structure around the M87* black hole. The future space-based Black Hole Explorer mission is expected to extend these capabilities, allowing for $\beta_2$ measurement of the strongly lensed $n=1$ image. In this paper, we explore the constraints $\beta_2$ measurements would impose on spacetime and
plasma geometries using a semi-analytic conical emission model. We show that
magnetic field orientation with respect to the emission cone qualitatively changes the dependence of $\beta_2$ modes on model parameters. For cone-aligned
magnetic fields, we find that the leading-order theoretical prediction from equatorial emitters of $\beta_{2,\, n=0} \approx\beta_{2,\, n=1}^*$ is the dominant trend even in off-equatorial models. Specifically, we show $\arg(\beta_{2,\, n=0}\,\beta_{2,\, n=1}^*) \approx 4\chi$, where $\chi$ is the angle determining in-cone
magnetic field orientation. We also find that $\arg(\beta_{2,\, n=0}\beta_{2,\, n=1})$ minimizes the effect of
magnetic field geometry while preserving a dependence on
spin that may be used to measure
spin direction. We find that observations of the
photon ring's $\beta_2$ complement the constraint from direct image polarization, and can greatly constrain
magnetic field structure even with an unknown external rotation measure. We also find that black hole
spin and emission cone opening angle would not be tightly constrained by $\beta_2$ alone, unless strong priors are placed on the
magnetic field geometry.
Read the full abstract ▾
All authors Vadim Bernshteyn, Daniel C. M. Palumbo, Dominic Chang, Tintin Nguyen
Astrophysics of Galaxies
The differences in the Narrow Line Region of nearby QSOs 1 and QSOs 2: II - Signatures of kinetic feedback
Gabriel R. Hauschild-Roier, Thaisa Storchi-Bergmann, Rogério Riffel et al. (+2 more)
We compare the integrated kinematic properties of the Narrow-Line Region (NLR) of ~1500 type 1 and ~700 type 2 QSOs at 0.4 < z < 0.5 using emission-line profiles from SDSS-IV spectra. The NLR [OIII] 5007 and Hbeta emission lines are fitted using a two-component model comprising a narrow (v_n, sigma_n) and a broad component (v_b, sigma_b), while fainter lines are fitted with a single Gaussian component. Both QSO types exhibit similar median narrow-component velocities (v_n ~ 0) and velocity dispersions (sigma < 200 km s^-1), consistent with motion driven by the host
galaxy's gravitational potential. However, parameters associated with the broad, high-velocity gas component (v_b, v_05, v_10, v_[NeV], sigma_b, W80 and W90) differ: QSOs 1 display larger blueshifts and broader emission lines than QSOs 2. This suggests that these components trace Active Galactic
Nuclei (AGN) outflows, that appear stronger in QSOs 1, leading to higher estimated mass-outflow rates (\dot{M}_out) and kinetic powers (\dot{{E}_out). Rather than offering absolute determinations of \dot{M}_out and \dot{E}_out – which remain subject to physical uncertainties – this statistical study supports the higher NLR excitation found for QSOs 1 in Paper I, as an orientation effect: in QSOs 1, we observe gas closer to the AGN core, where velocities and velocity dispersions are intrinsically higher. Nevertheless, the trend of QSOs 2 exhibiting higher average [OIII] luminosities than QSOs 1 suggests an evolutionary contribution, where QSOs 2 represent an early obscured AGN phase followed by a blowout phase that reveals the central core as a QSO 1.
Read the full abstract ▾
All authors Gabriel R. Hauschild-Roier, Thaisa Storchi-Bergmann, Rogério Riffel, Vincenzo Mainieri, Lara Gatto
Cosmology and Nongalactic Astrophysics
Weak lensing, Big Magnification: Recovering hidden lensing information from galaxy positions
Alex Alarcon and Carles Sánchez
Galaxy clustering and weak gravitational
lensing are powerful cosmological probes, traditionally combined through
galaxy clustering and
galaxy-
galaxy lensing in a $2\times2$pt analysis. An alternative is the foreground-background clustering cross-correlation induced by
lensing magnification, but measurements have achieved lower signal-to-noise than shear-based
lensing. We show that, for deep photometric samples, cancellation between
galaxies with positive and negative magnification responses can suppress this signal. Using DES Year 6 photometry and Balrog synthetic-source injections, we explore high-
redshift ($z\simeq0.7$-$2.5$) samples split by the sign and amplitude of their magnification response. This separation reduces cancellation and can increase both signal-to-noise and cosmological constraining power. We call the combination of foreground clustering and foreground-background cross-correlations with response-selected background samples BigMag. Forecasts with DES-like simulated data vectors show that, for an optimistic sample configuration and sufficiently precise response calibration, BigMag can achieve constraining power comparable to traditional $2\times2$pt using
galaxy positions alone. The same samples also enhance inverse
galaxy-
galaxy lensing (IGGL), a position-shear correlation dominated by magnification when the position sample lies behind the shape sample. Combining BigMag and IGGL further self-calibrates the magnification responses and yields marginalized $S_8$ constraints comparable to traditional $3\times2$pt analyses, and tighter for the more precise calibration scenarios considered here. The framework also enables near-zero-response samples for traditional $3\times2$pt and
geometric lensing-ratio analyses. These results motivate further optimization and validation of
galaxy selections to realize magnification as a complementary cosmological probe. [Abrg.]
Read the full abstract ▾
High Energy Astrophysical Phenomena
Blasts from the Past: UHECR Excesses from a Population of GRB 21009A-like Transients
Nestor Mirabal
The most prominent feature in the ultra-high-energy
cosmic ray (UHECR) sky is a significant excess of events from the vicinity of Centaurus A (Cen A). In this paper we investigate whether the excess may be caused by a past GRB 221009A-like event rather than Cen A itself. If an extraordinary gamma-ray burst (GRB) went off in one of the dwarf
galaxies within the Cen A/M83 group, intergalactic
magnetic deflections would naturally spread out and delay its
cosmic ray signal, making it visible for $\sim 2\times 10^{5}$ years. Scaling this up, we model a local population of these exceptionally bright, narrow-jet transients within the \text{Greisen–Zatsepin–Kuzmin} (GZK) horizon. For a local volumetric rate of $\dot n_0\simeq4\times10^{-8}\ {\rm Mpc^{-3}\,yr^{-1}}$ and a jet half-opening angle of $0.8^\circ$, we estimate $\simeq3-7$ UHECR excesses across the sky at any given time. Varying the jet opening angle, GZK volume, and visibility time results in a broader range of excess values. It is possible to test this hypothesis by comparing the population predictions against existing and upcoming UHECR anisotropy data obtained by the Pierre Auger Observatory and the
Telescope Array.
Read the full abstract ▾
Instrumentation and Methods for Astrophysics
The Nancy Grace Roman Space Telescope Wide Field Instrument: Characterization of the Brighter-Fatter Effect in a Roman H4RG-10 Detector using the Talbot Effect
Jennie Paine, Ami Choi, Christopher Merchant et al. (+14 more)
The Nancy Grace Roman Space
Telescope will conduct several community-driven surveys using its Wide Field Instrument (WFI), which contains 18 Teledyne H4RG-10 near-infrared detectors in the focal plane. Roman's wide area survey to measure weak gravitational
lensing places particularly stringent requirements on point spread function (PSF) precision for the WFI. The brighter-fatter effect (BFE) is a nonlinear detector effect caused by the deflection of new charge away from pixels with previously accumulated charge during an exposure. As a result, the PSF measured at the detector depends on the charge contrast between pixels, and therefore the effective PSF for astronomical sources is a function of flux contrast and integration time. We present characterization of the BFE observed in a non-flight H4RG by projecting a grid of bright point sources onto the detector using the Talbot Illuminator at the NASA Goddard Space Flight Center Detector Characterization Lab. We find that the effective area of a pixel decreases by $(-2.18\pm0.04) \times 10^{-6}$ per electron of charge contrast with its neighbors, corresponding to a measurable increase in the effective PSF size over the course of an exposure. Despite charge migration, the total signal detected in the vicinity of a bright source is roughly conserved. We also analyze flat field statistics for the same detector to measure the total inter-pixel nonlinearity (IPNL), which is dominated by BFE. We present a method to correct BFE in H4RG images using the flat field IPNL results, adapted from an extant optical correction technique. The correction reduces the observed BFE by about a factor of 25 as measured by the effective pixel area change, but there is remaining nonlinearity in the corrected data. We discuss possible sources of residual nonlinearity and suggest avenues to investigate optimal BFE correction in Roman survey images.
Read the full abstract ▾
All authors Jennie Paine, Ami Choi, Christopher Merchant, Timothy D. Brandt, Jeffrey Kruk, Joshua E. Schlieder, Edward J. Wollack, Analia Cillis, Jahmour J. Givans, Robert Hill, Christopher Hirata, Dana R. Louie, Gregory Mosby, Anna Porredon, Bernard J. Rauscher, Maxime J. Rizzo, Rujula Yete
High Energy Astrophysical Phenomena
The Virgo Cluster as a Case Study for Ancient Cosmic Ray Halos in Radio and X-rays
Philip F. Hopkins, Emily M. Silich, Jack Sayers et al. (+2 more)
Virgo is the nearest cool core (CC)
galaxy cluster, and is archetypal of the class of X-ray weak CCs. Despite the X-ray continuum implying a large cooling rate ($\gtrsim 10\,{\rm M_{\odot}\,yr^{-1}}$), measurements of cooler gas phases, dust, and
star formation show almost no cooling outside the M87
nucleus. It is also known that M87$^{\ast}$ is a prodigious source of
cosmic ray (CR) leptons observed in
radio and $\gamma$-rays, and recent
radio observations have shown that the M87
radio halo is low-frequency and its spectral index steepens rapidly away from the injection region+jets, consistent with an aging, low-energy CR population. We demonstrate that coupling X-ray and
radio to newer Faraday rotation limits on the
magnetic field, this implies the CRs within the CC radius ($\lesssim 40$kpc) must contribute significantly to the total pressure and soft X-ray emission, through a combination of Coulomb heating the gas and inverse-Compton (IC) scattering microwave background
photons to $\sim$keV. We show this can explain the apparent correspondence between jet/
radio power and X-ray cooling luminosity, and why the X-ray inferred cooling rate appears much larger than otherwise observed. This would also explain why the central X-ray inferred
metallicity at $\lesssim 10\,$kpc appears to be suppressed relative to the UV/optical inferred
metallicity (in a wavelength-dependent manner). Compared to more extreme
radio+X-ray sources like Perseus, we find the observations require a softer 'escaping' CR spectrum (escaping or accelerated outside $\gtrsim 1\,$kpc from M87$^{\ast}$).
Read the full abstract ▾
All authors Philip F. Hopkins, Emily M. Silich, Jack Sayers, Sam B. Ponnada, Isabel S. Sands
Astrophysics of Galaxies
Internal Radiative Feedback Triggers Global Collapse and Direct-Collapse Black Hole Formation in Metal-free Atomic-Cooling Haloes
Masaki Kiyuna, Sunmyon Chon, Kazuyuki Omukai et al. (+1 more)
The formation of heavy seed black holes from the collapse of supermassive
stars (SMSs) is a promising pathway to the supermassive black holes (SMBHs). In the conventional direct-collapse scenario, however, SMS formation requires an extremely strong external far-ultraviolet (FUV) field to suppress H$_2$ cooling and fragmentation. Here, we use cosmological radiation-hydrodynamic simulations to show that SMSs can form in metal-free atomic-cooling
haloes even under subcritical FUV backgrounds with $J_{21}=1$-$10^2$. We follow the
evolution for $\sim1$-$2~{\rm Myr}$ after the onset of
star formation, including FUV and ionizing radiation from
stars formed within the
halo.
Star formation proceeds through a characteristic two-stage
evolution. H$_2$ cooling initially induces fragmentation and the formation of ordinary Pop III
stars. Internal FUV radiation from these
stars then photodissociates H$_2$ and suppresses further fragmentation, while the surrounding warm gas reservoir contracts under self-
gravity and undergoes global collapse through atomic cooling. This collapse drives inflow rates of $\sim0.1$-$1~{\rm M_\odot~yr^{-1}}$ and produces rapidly accreting protostars that reach $\sim2$-$6\times10^4~{\rm M_\odot}$ by the simulations end. Since rapid
accretion is still ongoing, these objects are expected to grow to $\sim10^5~{\rm M_\odot}$ SMSs and then form direct-collapse black holes (DCBHs). The global collapse is accompanied by clustered
star formation, producing a compact, top-heavy stellar system around the SMSs. The estimated DCBH abundance, $n_{\rm DCBH}\sim10^{-3}$-$10^{-2}~{\rm cMpc^{-3}}$, is high enough to provide a plausible progenitor population for Little Red Dots and present-day SMBHs. Our results demonstrate that internal stellar feedback can trigger, rather than prevent, SMS formation, substantially relaxing the external FUV requirement for heavy-seed formation.
Read the full abstract ▾
All authors Masaki Kiyuna, Sunmyon Chon, Kazuyuki Omukai, Raffaella Schneider
Cosmology and Nongalactic Astrophysics
Anisotropic cosmic birefringence estimates for forthcoming CMB experiments
Matteo Longo Minnolo, Matteo Billi and Giuseppe Puglisi
Cosmic Birefringence (CB) is a unique probe of physics beyond the Standard Model, potentially sourced by an
axion-like field coupled to
photons via a Chern-Simons interaction. Recent Planck analyses have strengthened evidence for a non-zero isotropic rotation angle, yet its anisotropic component remains undetected, despite being the key to distinguishing a homogeneous quintessence-like field from spatially varying
axion-like dark matter. We forecast the sensitivity of forthcoming ground- and space-based CMB experiments to anisotropic CB, applying a patch-based localization technique to simulated CMB-plus-noise maps with white noise levels representative of Simons Observatory SAT- and LiteBIRD-like sensitivities. Local rotation angles are reconstructed on independent sky patches by minimizing the $\chi^2_{EB}$ statistic built from the $EB$ D-
estimator. Under our idealized simulations, the forecast angular power spectrum improves current Planck-based constraints on the CB anisotropy statistical uncertainty by a factor of 26-40 for a satellite-like mission and 11-15 for a realistic ground-based footprint. Translating these into constraints on the scale-invariant amplitude, fitting the reconstructed bandpowers with a scale-invariant amplitude model, we forecast with a 95 % C.L. $A_{\rm CB} < 3.5\times10^{-4}\,{\rm deg}^2$ for the space-like mission and $A_{\rm CB} < 7.1\times10^{-4}\,{\rm deg}^2$ for the ground-based footprint, improving on the current full-sky Planck constraint by a factor of about 20 and 10, respectively. These values represent upper bounds on the achievable gain, and indicate that forthcoming CMB experiments will be able to further shed light on anisotropic CB.
Read the full abstract ▾
Solar and Stellar Astrophysics
Spectroscopic monitoring of long secondary period variables. The case of J-type carbon stars
L. Planquart, A. Jorissen and H. Van Winckel
Long-secondary-period (LSP) variables are a subclass of long-period variables whose origin is a matter of debate. J-type carbon
stars are a subclass of carbon
stars enriched in 13C, and the origin of this chemical peculiarity is unclear. In this paper, we report on the discovery of a LSP in two J-type carbon
stars: VZ Per and UV Cam. Methods. A decade-long spectroscopic monitoring was used to obtain a long-term radial-velocity curve for the two
stars. From a frequency analysis, we isolated a LSP signal. The retrieved periodicity was then compared with changes in spectral profiles and available light-curve variability to further constrain the origin of the modulation. Results. For VZ Per, the LSP derived from the radial-velocity curve (~960 days) is correlated with the light-curve dimming event and a variation in the Balmer absorption line profile. These results translate into changes in the gas and dust column densities with the phase of the LSP, with the maximum gas column density occurring ahead of the dust. For UV Cam, the radial velocity monitoring yields a period of ~1178 d with an amplitude of about 1 km/s. Interpreting the RV modulation as a Keplerian signal for both
stars, a low-mass (<0.1Msun) close companion is found. In this scenario, variations in gas and dust column densities with (orbital) phase trace the material in the expanding comet-like tail trailing the substellar companion. Conclusions. These observations provide time-dependent variations of the gas and dust in LSP variables that are consistent with the current binary scenario. Furthermore, the detection of LSP among J-type carbon
stars anchors their current evolutionary status in the dust-producing region of the thermally-pulsing AGB phase.
Read the full abstract ▾
Astrophysics of Galaxies
SCALES. II. The Internal Composition of Giant Star-Forming Clumps at $z = 1 - 4$
Boris S. Kalita, Adélaïde Claeyssens, Luis C. Ho et al. (+12 more)
Star-forming structures of scale $\sim0.5-1\,\mathrm{kpc}$, dubbed 'giant'
star-forming clumps, are routinely detected in unlensed surveys of $z > 1$
galaxies. Two scenarios are usually invoked to explain their existence – genuine physical structures or resolution-driven artifacts – yet distinguishing between them requires characterizing their internal structure. In this work, part of the
Star-Forming Clumps As Layered Emergent Structures (SCALES) series, we hence ask: What is inside a giant clump? We analyze 23 lensed
galaxies at $z=1-4$ with JWST/NIRCam using difference-of-Gaussian decomposition to model (lensed) clumps at $\sim 100-300\,\mathrm{pc}$ scales, and the surrounding extended component (EC) at giant clump scales. Associating clumps to ECs, we effectively identify 44 giant clumps. Characterizing giant clump stellar mass composition using the most massive member clump and the remaining constituent clumps, we find it consistent with random sampling of the host
galaxy's clump population, and hence the clump stellar mass function. This conclusion agrees qualitatively with both prevailing scenarios – (I) dominant long-lived giant clumps, although requiring constant renewal of their constituents, and (II) giant clumps as mere blended clump associations. However, most models make no strong claims about their internal mass distribution beyond order-of-magnitude statements, and our observations thus provide an empirical constraint against which such models can be re-evaluated. Finally, using the total mass budget of clumps and ECs, we find that the clump stellar mass function cannot be described by a single power law of slope $\approx 2$, but requires a break to a shallower slope at $\sim 10^{7.4}\,\mathrm{M_{\odot}}$.
Read the full abstract ▾
All authors Boris S. Kalita, Adélaïde Claeyssens, Luis C. Ho, Miroslava Dessauges-Zavadsky, Natascha M. Förster Schreiber, Emanuele Daddi, John D. Silverman, Naval Kishor Bhadari, Changhao Chen, Fangzhou Jiang, Ke Wang, Jinning Liang, Alvaro Segovia Otero, Jinyi Shangguan, Francesco Sinigaglia
Astrophysics of Galaxies
SCALES. I. Bridging Lensed Clump - Giant Clump Scales in Lensed Galaxies at $z=1-4$
Boris S. Kalita, Adélaïde Claeyssens, Luis C. Ho et al. (+12 more)
Dense
star-forming regions in $z>1$
galaxies, often termed 'clumps', have been studied across two distinct regimes of
telescope resolution, each motivating interpretations in tension with the other. In the SCALES series (
Star-Forming Clumps As Layered Emergent Structures), we aim to connect
star-forming structures across scales, from the $\sim100\,\mathrm{pc}$ clumps in lensed studies to the $\sim\mathrm{kpc}$-scale ”giant” clumps in unlensed surveys. In this first paper, we present a difference-of-Gaussian (DoG) decomposition that simultaneously models $\sim100-300\,\mathrm{pc}$ (lensed) clumps and $\sim\mathrm{kpc}$-scale component (the extended component, or EC), which would together constitute the giant clumps seen at lower resolution. Here the EC is treated as a scale-separated local background rather than a physical object, absorbing all light that is not a compact clump. Applying this to 23 moderately lensed ($\mu \approx 2-9$)
galaxies at $z_{spec} = 1-4$ to evaluate clump properties (deferring ECs and giant clumps to the next work), we find their stellar mass to be capped at $\sim 10^{8.5}\,M_{\odot}$. We measure clump stellar mass function slope of $2.19 \pm 0.06$, which is higher than typical, and may reflect a physical truncation at the massive end. We also show that empirical correlations of clump surface densities and clump-to-host mass ratio with
redshift are exaggerated by
redshift-dependent detection bias, so $\sim100-300\,\mathrm{pc}$ clumps are largely co-similar across our range ($z = 1-4$). Finally, combining clump mass, size and age estimates with literature gas-dispersion measurements at similar scales, we argue that $\sim100\,\mathrm{pc}$ clumps are themselves composed of
star-cluster-like sub-components at much smaller scales.
Read the full abstract ▾
All authors Boris S. Kalita, Adélaïde Claeyssens, Luis C. Ho, Miroslava Dessauges-Zavadsky, Natascha M. Förster Schreiber, Emanuele Daddi, John D. Silverman, Naval Kishor Bhadari, Changhao Chen, Fangzhou Jiang, Ke Wang, Jinning Liang, Alvaro Segovia Otero, Jinyi Shangguan, Francesco Sinigaglia
Instrumentation and Methods for Astrophysics
Ana Sofía M. Uzsoy, Claire Lamman, Peixin Zhu et al. (+1 more)
We present SONDE (SOrted Neighbor Distance
Embedding): a scalable
manifold learning approach to create a nuanced, continuous, low-dimensional representation of the geometry of
galaxies' local environments. SONDE is a variation on Isomap that uses similarity distances between
galaxy neighborhoods to create an
embedding space, within which
galaxies cluster according to their neighborhood geometries. We additionally present a novel method to project different
datasets into the same
embedding space, enabling comparisons of environmental
embeddings across
redshifts. We demonstrate this method on the TNG100 simulations at $z = 0 - 5$ and show that the
embedding values evolve with
redshift and correlate with
galaxies' physical properties. We train a neural network to predict physical properties based on environmental features and show that our first
embedding dimension outperforms a standard environmental quantifier, the number of neighbors, while the top three dimensions encode as much environmental information as a ten-bin radial profile. Our results are consistent with known density correlations, including
galaxy halo mass, central vs. satellite status, and quenching. SONDE provides a straightforward way to encode subtleties of
galaxy environments that could have significant implications for future analysis of
galaxy-environment interactions.
Read the full abstract ▾
All authors Ana Sofía M. Uzsoy, Claire Lamman, Peixin Zhu, Melanie Weber
Cosmology and Nongalactic Astrophysics · Cross-listed from hep-th
Comment on ”Chiral electromagnetic surface waves on Chern-Simons interfaces” Phys.Rev.D114(2026)L051903 and on arXiv:2606.12513 by N. Kaloper
Igor Bandos and Bohdan Zvorskyi
We demonstrate that Maxwell electrodynamics interacting with a planar Chern-Simons interface does not have plane wave solutions localized on the interface. We re-examine the derivation of such waves presented by N. Kaloper in [Phys.Rev.D114(2026)L051903] and show that at an intermediate step certain terms were missed in an equation therein. Taking these terms into account changes the final conclusion of [Phys.Rev.D114(2026)L051903]. We also show that the method used in [arXiv:2606.12513 [hep-th]] to reproduce the same result is not consistent.
Read the full abstract ▾
Cosmology and Nongalactic Astrophysics
Map-based asymmetric beam treatment: application of real-space beam patterns in CMB data analysis
Artem Basyrov
Real
telescope beams are asymmetric, breaking the simple $B_{\ell}$ factorisation in harmonic space and coupling modes across $\ell$ and $m$. We develop a map-domain treatment in which beam convolution is a local, scan-dependent operation applied directly to the time-ordered data (TOD), accommodating the full beam shape and giving a direct handle on intensity-to-polarisation ($I \rightarrow P$) leakage. A noiseless validation against spherical-harmonic convolution reproduces the input temperature and $B$-mode power spectra up to $\ell \simeq 1000$, well beyond the range of primordial $B$-mode science. We outline how the operation maps onto a sparse linear BeamOperator for modular map-making.
Read the full abstract ▾
Cosmology and Nongalactic Astrophysics · Cross-listed from hep-ph
Higgsino dark matter compatible with the LUX-ZEPLIN high-energy nuclear-recoil event and IceCube constraints
Katherine Freese and Dionysios P. Theodosopoulos
We examine Higgsino dark matter (DM) as a potential explanation of the $248~\mathrm{keV}$ nuclear-recoil event of interest reported by the LUX-ZEPLIN (LZ) experiment, taking into account IceCube constraints on DM annihilation in the Sun. In the nearly pure Higgsino limit, two neutral Majorana states separated by a small mass splitting $\delta$ are connected by an off-diagonal coupling to the $Z$
boson, providing a natural realization of inelastic DM. Using a likelihood analysis, we identify 90% confidence regions compatible with the LZ event and consistent with the null results of IceCube searches, both with and without including a constraint from the absence of events in the LZ high-energy sideband. In our LZ analysis, we consider the DM distribution in the Standard
Halo Model alone as well as possible enhancements of the high-speed tail induced by the Large Magellanic Cloud (LMC). We present four variants of bounds from IceCube on Higgsino dark matter, depending on various assumptions on cooling channels in the Sun, motivated by severe theoretical uncertainties about Higgsino-nucleon elastic scattering (unimportant for direct detection but crucial for IceCube bounds). Whereas the thermal Higgsino with a mass of $1.1~\mathrm{TeV}$ remains only marginally compatible with both the LZ event and the IceCube limits when the LMC-induced high-speed tail is included and both elastic cooling in the Sun and the LZ high-energy sideband constraint are neglected, higher mass Higgsinos are excellent candidates for the LZ event in light of IceCube constraints. Depending on the
halo distribution, cooling interactions, and whether the LZ high-energy sideband is included, the compatible regions in the Higgsino parameter space $(m_\chi,\delta)$ extend from masses of $\sim2~\mathrm{TeV}$ to hundreds of TeV or higher, with mass splittings ranging approximately from $350$ to $525~\mathrm{keV}$.
Read the full abstract ▾
Earth and Planetary Astrophysics
Temporal Variability of Titan's Middle-Atmospheric Zonal Winds from Southern Fall to Late Winter (2016-2023)
Martin A. Cordiner, Yuan Lian, Juan M. Lora et al. (+10 more)
Previous ALMA observations have revealed unexpectedly strong and rapid variations in Titan's high-altitude equatorial zonal winds, which present a challenge to our understanding of this moon's atmospheric dynamics. Here we report further measurements of Titan's zonal wind field at middle atmospheric altitudes $\approx200$-490 km, based on ALMA observations of spatially and spectrally resolved CH$_3$CN emission between 2016-2023 (corresponding to a solar longitude $L_s=81.6^{\circ}$-$156.4^{\circ}$, spanning Titan's late southern autumn to late winter). These observations indicate substantial, ongoing, rapid temporal variability of Titan's zonal winds, on timescales as short as $\approx1$ Earth month ($0.9^{\circ}$ in $L_s$). The strongest variability is at (near-)equatorial latitudes where the zonal winds are fastest (up to $240\pm26$ ms$^{-1}$), with repeated $\sim40$ ms$^{-1}$ fluctuations occurring between $L_s=146.0^{\circ}$-$156.4^{\circ}$. The observed longer-term trends are qualitatively well-reproduced by two independent, state-of-the-art general circulation models (GCMs), which match the observed decrease in zonal wind speeds over a broad range of latitudes between $L_s=81.6^{\circ}$-$146.0^{\circ}$, followed by a more moderate increase between $L_s=146.0^{\circ}$-$156.4^{\circ}$. The wind speeds at mid-to-high latitudes ($\sim-45^{\circ}$ south) are also typically reasonably well reproduced by the GCMs (differing by $\lesssim30$%). However, the equatorial wind speeds are up to a factor of $\sim2$ faster than model predictions (with the greatest discrepancy around solstice; $L_s\approx90^{\circ}$). Rapid temporal variability of the retrieved zonal winds indicates the presence of strong atmospheric instabilities that are not well reproduced by models, suggesting a need for future GCM improvements.
Read the full abstract ▾
All authors Martin A. Cordiner, Yuan Lian, Juan M. Lora, Nicholas A. Lombardo, Lucy Wright, Jonathon Nosowitz, Richard Cosentino, Nicholas A. Teanby, Conor A. Nixon, Alexander E. Thelen, Claire E. Newman, Steven B. Charnley, Eliot F. Young
Astrophysics of Galaxies
Searching for Green Pea Galaxies in the SFACT Survey
Kristin N. Baker, John J. Salzer, Brooke Kimsey-Miller et al. (+5 more)
Green Pea
galaxies (GPs) are a class of rare, extreme
star-forming
galaxies whose physical properties closely resemble high-
redshift Ly-{\alpha} emitting
galaxies. Their high equivalent width [O III] emission lines make them readily identifiable in surveys of emission-line
galaxies like the on-going deep, narrowband
Star Formation Across
Cosmic Times (SFACT) survey. In this study, we use broadband gri colors and [O III] equivalent widths derived from narrowband images to select a new sample of ~120 GP candidates from a catalog of [O III]-detected
galaxies identified in the SFACT survey. All SFACT GP candidates have spectroscopically confirmed
redshift in the range z = 0.31-0.51. The median apparent magnitude of our sample is g = 22.9. We compare the properties of our GP candidate sample to other samples of known GPs. We find that the excellent depth of SFACT allows us to detect GP candidates to lower luminosities than these comparison samples. This is the first catalog of SFACT GP candidates; additional candidates will be added as the spectroscopic follow-up of the SFACT survey is completed.
Read the full abstract ▾
All authors Kristin N. Baker, John J. Salzer, Brooke Kimsey-Miller, Samantha W. Brunker, David J. Carr, Jennifer Sieben, Steven Janowiecki, Samir Salim
Cosmology and Nongalactic Astrophysics
Baryonic Imprints on DM Halos: the concentration-mass relation and its dependence on 28 model parameters in the CAMELS suite
Cami Delgado and Dhayaa Anbajagane
The
evolution of baryons in
halos, as well as their gravitational impact on the total-matter phase space, has a rich phenomenology and is vital in answering many questions in both cosmology and astrophysics. We use the CAMELS simulation suite to quantify the impact of twenty-three different
galaxy formation parameters/processes (as well as five cosmological parameters) on the concentration–mass relation, $c_{\rm vir}$ - $M_{\rm vir}$, which characterizes the radial density distribution in
halos. We construct a simulation-informed nonlinear model for concentration as a function of
halo mass,
redshift, and twenty-eight cosmological/astrophysical parameters. This is done using 2048 simulations of the IllustrisTNG
galaxy formation model from the CAMELS suite. We extract the imprints of
galaxy formation across a wide range in mass $M_{\rm vir} \in [10^{11}, 10^{14.5}]$ $M_{\odot}/h$ and in
redshift $z \in [0, 3]$, finding clear mass- and
redshift-dependent features in each of the different feedback mechanisms. From our measurements, we construct a three-component phenomenological model that can include astrophysical imprints in the concentration–mass relation in a fast and simple manner.
Read the full abstract ▾
Cosmology and Nongalactic Astrophysics
Probing Early Phases of the Epoch of Reionization with the $\mathrm{kSZ}^{2}\times21\,\mathrm{cm}^{2}$ Cross-Correlation
Wen-Qing Guo, Yin-Zhe Ma, Adam Lidz et al. (+2 more)
Observations of the Epoch of Reionization (EoR) provide key insights into the nature of the first luminous sources and the thermal state of the intergalactic medium (IGM). Cross-correlations between the kinetic Sunyaev–Zel'dovich (kSZ) effect and neutral hydrogen (HI) 21-cm emission offer a promising probe of this era, sensitive to both the ionization and thermal histories of the early Universe. We investigate the cross-correlation of the squared kSZ field with the squared 21-cm intensity-mapping field ($\mathrm{kSZ}^{2}\times21\mathrm{cm}^{2}$) over $z\simeq9$–$16$, focusing on the impact of spatial fluctuations in the HI
spin temperature. This higher-order statistic avoids line-of-sight cancellations in the kSZ signal, while squaring the 21-cm field enables non-vanishing correlations with pairs of equal and opposite high-$k_\parallel$ modes accessible outside the foreground wedge. We forecast the cumulative signal-to-noise ratio ($\mathrm{S/N}$) for several combinations of 21-cm and CMB experiments, including realistic instrumental noise. For a fiducial heating history and an optimistic foreground-avoidance scenario ($k_\parallel\leq0.1\,h\,\mathrm{Mpc}^{-1}$), we find $\mathrm{S/N}\simeq5.89$ for SKA-Low AA$^\ast\times$CMB-HD and $\simeq3.62$ for HERA$\times$CMB-HD. If the foreground wedge extends to the horizon, these decrease to $2.94$ and $2.85$, respectively. Our results demonstrate that $\mathrm{kSZ}^{2}\times21\mathrm{cm}^{2}$ is sensitive to the thermal
evolution of the IGM as well as its ionization structure, providing complementary constraints on the high-
redshift thermal and reionization histories.
Read the full abstract ▾
All authors Wen-Qing Guo, Yin-Zhe Ma, Adam Lidz, Steven Murray, Hemanth Potluri
Instrumentation and Methods for Astrophysics
Design, Fabrication, and Free-Space Characterization of a Two-Photon-Polymerized Nano-printed Photonic Lantern
Kyra Watts, Natasha Popenoe, Benjamin Gerard et al. (+6 more)
Photonic lanterns provide an interface between multimode optical fields and arrays of single-mode waveguides, making them promising components for modal filtering, wavefront sensing, and high-contrast astronomical instrumentation. We present the design, simulation, two-
photon-polymerization fabrication, and free-space characterization of a compact photonic lantern optimized for operation at $ 1050~\mathrm{nm} $. The device was designed to transform a multimode input into five nominally single-mode output waveguides. Eigenmode-expansion simulations in Ansys Lumerical MODE were used to optimize the lantern geometry while minimizing insertion loss and output-channel power nonuniformity. The optimized structure was fabricated using a Nanoscribe Photonic Professional GT2 two-
photon-polymerization system and developed as a standalone
polymer-waveguide component. The fabricated lantern was characterized using a free-space optical setup consisting of a $ 635~\mathrm{nm} $
laser for preliminary characterization, collimation and focusing optics, and camera-based imaging of the transmitted fields. Measurements were used to assess optical throughput, output intensity distribution, and light-guiding performance. Differences between simulated and measured results may arise from the wavelength mismatch, fabrication tolerances, material and surface-scattering losses,
alignment errors, and deviations from the idealized material and
geometric parameters used in simulation. These results demonstrate a compact, additively manufactured photonic-lantern platform and establish a pathway toward free-space-coupled astrophotonic systems for future high-contrast
exoplanet-imaging instrumentation.
Read the full abstract ▾
All authors Kyra Watts, Natasha Popenoe, Benjamin Gerard, Paul Pax, Dominic Sanchez, David Feng, C. Cole Dunn, Cari Johnston, Xiaoxing Xia
Cosmology and Nongalactic Astrophysics
A novel, fast, and accurate code for cosmological loop calculations
Tjark Harder, Luca Amendola, Thiago S. Pereira et al. (+1 more)
We introduce neckar, a public code for the one-loop matter and
galaxy power spectrum, as well as correlation function, in the Eulerian Effective Field Theory of Large-Scale Structure (EFTofLSS). It is based on the FFTLog expansion, and is designed for fast and accurate parameter inference from large-scale structure data, making it a powerful tool for high-dimensional
Bayesian analyses of current and upcoming
galaxy surveys. neckar combines several numerical and analytical improvements, including the separation between pre-computable and cosmology-dependent contributions, a semi-analytic treatment of the Alcock-Paczynski effect for power spectrum multipoles, and an implementation of the
symmetry-based bootstrap kernels, allowing straightforward applications to a broader class of cosmological models. The code also incorporates an improved infrared resummation scheme that corrects previous implementation inaccuracies, and which led to errors of the order of 1% for the quadrupole, and of 10% for the hexadecapole at scales $k \gtrsim 0.1 h \textrm{Mpc}^{-1}$, as well as an asymptotic treatment that extends the range of accurate predictions into mildly non-linear scales $k \sim 0.4 h \textrm{Mpc}^{-1}$. This leads to relevant corrections in the correlation function around the BAO peak. Taken altogether, these improvements render neckar up to two orders of magnitude faster than similar existing codes without relying on emulators, and at the same time improving numerical accuracy. The code is written in C and is distributed with a Python wrapper for convenience.
Read the full abstract ▾
All authors Tjark Harder, Luca Amendola, Thiago S. Pereira, Miguel Quartin
High Energy Astrophysical Phenomena
Forward Bayesian Inference for the Binary Black Hole Populations
Poulami Dutta Roy, Tanmaya Mishra, Achal Kumar et al. (+1 more)
We present PopCWB, a
Bayesian framework for the inference of the binary black hole (BBH) population based on the unmodeled search pipeline coherent WaveBurst (cWB). The standard population analysis takes an inverse approach by inferring the underlying population model parameters for a given set of detected events using the individual posterior samples. In PopCWB, we take a forward approach to population inference by varying population models to identify the most optimal one which describes the observed events. Rather than using event-level posterior samples, PopCWB uses a large set of simulated events reconstructed by cWB and their total mass, estimated with a machine-learning regression, to construct marginal probability distributions. These marginal probabilities are then used in the construction of the likelihood. We apply PopCWB to BBH events detected by cWB during the third observing run (O3) of the LIGO–Virgo–KAGRA detectors. We constrain an astrophysically motivated BBH population model that incorporates the effects of pulsational pair-instability
supernovae and dynamical mergers. The analysis predicts a maximum black hole mass of $\mathbf{45.5^{+5.3}_{-6.5} M_{\odot}}$ from stellar
evolution and an inferred local BBH merger rate of $\mathbf{23.1^{+11.3}_{-8.4} \, Gpc^{-3} yr^{-1}}$. We compare these results with the existing population models from the literature.
Read the full abstract ▾
All authors Poulami Dutta Roy, Tanmaya Mishra, Achal Kumar, Sergey Klimenko
Cosmology and Nongalactic Astrophysics · Cross-listed from hep-ph
Big Bang Nucleosynthesis Constraint on $B$-mesogenesis
James M. Cline, Jonas Frerick, Sebastian A. Naja et al. (+1 more)
$B$-mesogenesis is a low-temperature baryogenesis mechanism, that uses $CP$-violation of the $B$
mesons in the standard model to fulfill the Sakharov conditions. It requires a late period of matter domination by a scalar field $\Phi$ that decays into $b\bar b$
quarks, reheating the Universe below the QCD phase transition. We investigate the impact of this mechanism on Big Bang Nucleosynthesis, with respect to the reheating temperature $T_{rh}$, and the mass of $\Phi$. Injection of
hadrons skewing
neutron/
proton interconversions are the most important effect, followed by
neutrino heating from $\Phi$ decays. For $M_\Phi\lesssim 100\,$GeV, $T_{rh}$ must be $\gtrsim 10\,$MeV.
Read the full abstract ▾
All authors James M. Cline, Jonas Frerick, Sebastian A. Naja, Yong Xu
Cosmology and Nongalactic Astrophysics
Dark Energy Survey Year 6 Results: fast and interpretable posterior predictive checks for correlated cosmic probes
C. Doux, J. Muir, A. Ferté et al. (+59 more)
We present a fast and numerically stable framework for conducting posterior predictive distribution (PPD) tests of internal consistency in correlated cosmological probes. Our method, developed as a validation check for the Dark Energy Survey (DES) Year 6 combined analysis of weak
lensing and
galaxy clustering, employs a Gaussian-mixture model to efficiently approximate the high-dimensional PPD and introduces a scalar consistency metric, $\Delta_{\rm PPD}$, defined as the fraction of the PPD at lower probability density than the observed data. This method avoids challenges related to calibration and numerical stability that impacted PPD methods previously used in DES Year 3. After demonstrating performance with a toy model, we confirm that when applied to DES Year 3 measurements, $\Delta_{\rm PPD}$ identifies the same inter-probe tensions as published, calibrated PPD results while requiring only minutes per test. We further validate the method on several noise realizations of simulated DES Y6 analyses, demonstrating that $\Delta_{\rm PPD}$ responds coherently to injected inconsistency, while highlighting two effects which can complicate the interpretation of PPD tests for increasingly complex models. First, internal tensions that can be absorbed as shifts in nuisance parameters become more difficult to detect. Second, poorly constrained directions in parameter space can induce projection effects in PPDs for disjoint sets of observables, producing reports of tension even for consistent data. We conclude that $\Delta_{\rm PPD}$ provides a practical PPD-based diagnostic for multiprobe unblinding, to be interpreted with care alongside other validation checks. This framework has already played an important role in DES analyses and is well suited for application to forthcoming Stage-IV surveys such as LSST, Euclid, and Roman, where fast, robust internal consistency tests will be essential.
Read the full abstract ▾
All authors C. Doux, J. Muir, A. Ferté, M. Raveri, D. Sanchez Cid, N. Weaverdyck, E. J. Baxter, W. d'Assignies, T. Karwal, A. Amon, D. Anbajagane, F. Andrade-Oliveira, M. R. Becker, J. Blazek, A. Carnero Rosell, C. Chang, J. M. Coloma-Nadal, M. Crocce, J. DeRose, S. Dodelson, G. Giannini, E. Krause, E. Legnani, N. MacCrann, J. Mena-Fernández, A. Porredon, J. Prat, C. Preston, M. Rodriguez-Monroy, P. Rogozenski, R. Rosenfeld, S. Samuroff, E. Sanchez, I. Sevilla-Noarbe, M. Soares-Santos, C. To, M. A. Troxel, M. Yamamoto, B. Yin, J. Zuntz, S. Allam, M. Aguena, D. Bacon, D. Brooks, R. Camilleri, R. Cawthon, L. N. da Costa, S. Desai, P. Doel, K. Glazebrook, K. Honscheid, D. Huterer, K. Kuehn, J. L. Marshall, R. Miquel, M. Paterno, A. A. Plazas Malagón, M. Smith, E. Suchyta, D. L. Tucker, V. Vikram, J. Weller