Astrophysics of Galaxies
PEARLS: Two Distinct Populations of AGN Hosts Moving Between Star Formation and Quiescence
Gibson B. Bowling, Rafael Ortiz III, S. P. Willner et al. (+29 more)
We present the results of AGN–host-
galaxy decomposition using JWST/NIRCam, HST/ACS, and HST/WFC3 imaging of the North Ecliptic Pole Time Domain Field (NEP-TDF). The light-profiles of 36 NIRCam-selected AGN candidates are modeled for measurement of their point sources, and point source-subtracted host-
galaxy emission is used in SED modeling for
star formation rate (SFR) estimation. Offsets from the canonical
star-forming main sequence (SFMS) show that the host
galaxies form two distinct groups distinguished by their
star formation: a “bridge” between the moderate SFRs of
radio sources and low SFRs of X-ray sources, and a cleanly-separated “branch” above $\Delta \rm SFMS = -1$ whose SFR trends positively with AGN fraction. Branch
galaxies include late-type
galaxies with X-ray and
radio detections and more dominant point sources that are most certainly AGN, while bridge
galaxies have predominantly early-type morphologies with weaker point sources that may be due to compact
stellar bulges. Both groups show evidence of recent transition between
star formation and quiescence, but neither group shows preference for higher or lower
stellar mass or
redshift, suggesting that
star formation in NIRCam-selected AGN-hosts is more strongly determined by AGN activity than by
stellar mass.
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All authors Gibson B. Bowling, Rafael Ortiz III, S. P. Willner, Seth H. Cohen, Timothy Carleton, Rogier A. Windhorst, Rolf A. Jansen, Christopher N. A. Willmer, W. Peter Maksym, Anton M. Koekemoer, Madeline A. Marshall, Rosalia O'Brien, Payaswini Saikia, Massimo Ricotti, Jordan C. J. D'Silva, Dan Coe, Christopher J. Conselice, Jose M. Diego, Simon P. Driver, Brenda L. Frye, Norman A. Grogin, Rachel Honor, Jake Summers, Nor Pirzkal, Aaron Robotham, Russell E. Ryan Jr., Brent M. Smith, Haojing Yan, Cheng Cheng, Liam Nolan, Heidi B. Hammel, Stefanie N. Milam
Cosmology and Nongalactic Astrophysics
Optimization of Weak Lensing Lightcone Simulations for Higher-Order Statistics in the LSST era
J. Mena-Fernández, C. Doux, J. Harnois-Déraps et al. (+9 more)
We present a framework for generating lightcone simulations tailored to the analysis of Stage-IV
cosmic shear data using Higher-Order Statistics (HOS). We revisit key design choices from previous simulation campaigns and re-optimize several internal parameters, benchmarking accuracy through changes in $\chi^2$ of
cosmic shear statistics under survey conditions mimicking 10 years of observations from the Legacy Survey of Space and Time (LSST). We find that discretizing the lightcone uniformly in scale factor yields higher accuracy than commonly adopted schemes such as uniform spacing in
redshift or comoving distance. While $N_{\rm part} = 1024^3$ simulation particles (corresponding to a mass resolution of $m_{\rm part} = 2.08\times10^{10}M_\odot$) is sufficient to model two-point statistics up to $\ell = 5000$, we observed significant instabilities on our full suite of HOS as the number of mass shells used in the lightcone construction, $N_{\rm shells}$, is varied. In contrast, simulations with $N_{\rm part} = 2048^3$ particles ($m_{\rm part} = 2.60\times10^{9}M_\odot$) robustly reproduce all statistics considered. In this higher-resolution configuration, $N_{\rm shells}$ can be reduced to $\sim50$ with only minor deviations, no larger than $0.1-0.3\sigma$ relative to our highest-resolution case ($N_{\rm shells}\sim100$). This has been explicitly verified through a comparison between our fiducial lightcone production mode based on slicing particle snapshots and an exact lightcone mode where individual particle trajectories are solved for at runtime. We further show that the particle density per pixel can be downsampled by a significant amount for $z>1.5$, saving large computational resources with no impact on the resulting statistics. These results guide the design of upcoming simulation campaigns geared towards forward-modeling and emulation-based analyses of Stage-IV data.
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All authors J. Mena-Fernández, C. Doux, J. Harnois-Déraps, K. Heitmann, C. Combet, P. Larsen, N. Frontiere, A. Bera, S. Samario-Nava, L. Castiblanco, C. Uhlemann, the LSST Dark Energy Science Collaboration
Cosmology and Nongalactic Astrophysics
$4\times3$ Point Correlation Functions in Galaxy Surveys: Impact of Baryonic Feedback
Avijit Bera, Joachim Harnois-Déraps, Juan Mena-Fernández et al. (+5 more)
We investigate the impact of baryonic feedback on two-point and three-point correlation functions (2PCFs and 3PCFs hereafter, respectively) involving
galaxy density fields (g) and weak
lensing shear fields (G), from simulated photometric catalogs of
galaxies. Specifically, we baryonify high-resolution simulation using a baryonic correction model (BCM) and explore the consequences down to sub-arcminute (arcmin) scales, varying two model parameters with the largest impact on our probes: $M_{\rm c}$, which governs the amount of gas expelled beyond the
halo boundary, and $\theta_{\rm ej}$, which encodes the maximal ejection radius relative to
halo boundary. We create
lensing maps and
galaxy catalogs assuming survey properties of the upcoming Year-10 data for the Vera C. Rubin Observatory's Legacy Survey of Space and Time (LSST), and investigate the impact of baryonic feedback on the observed correlations, including the
galaxy–
galaxy–shear (ggG) and the
galaxy–shear–shear (gGG) 3PCFs, which are measured, for the first time from simulations, with TreeCorr. Focusing on equilateral 3PCFs, we find that small scales are more heavily affected by baryonic effects than the corresponding 2PCFs, by up to 90 percent depending on the probe,
redshift and BCM model. The
galaxy–
galaxy–
galaxy (ggg) 3PCF is significantly affected at scales smaller than about 4 arcmin; a similar effect occurs at 10 arcmin for the ggG 3PCF, at 40 arcmin for the gGG 3PCF, and at about a degree for the shear–shear–shear (GGG) 3PCF. These four three-point statistics, which are collectively referred to as the $4\times3$PCFs, can be used at large scales to robustly constrain cosmological parameters. At smaller scales, their enhanced sensitivity to baryonic effects provides valuable leverage for constraining the BCM parameters and supplying informative priors. [Abridged]
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All authors Avijit Bera, Joachim Harnois-Déraps, Juan Mena-Fernández, Mike Jarvis, Cyrille Doux, Katrin Heitmann, Mustapha Ishak, The LSST Dark Energy Science Collaboration
Solar and Stellar Astrophysics
Investigating the Unresolved Binary Population in Gaia DR3 Using Multi-Wavelength Photometry
Andrew Malcolm Graham Soon
The
Gaia DR3 and Non-Single-
Star (NSS) catalogs are currently the definitive sources for binary systems (
Gaia Collaboration 2023). While this affords an invaluable asset to the astronomical community, there are suspected limitations. To address these constraints, we introduce a filtering regime that can be applied to raw data. This study introduces the "Triple Constraint" framework for use on
Gaia DR3 data through the application of multi-wavelength cogent evidence. Using Topcat, we cross-matched the WDS Supplement with the
Gaia DR3, 2MASS, and Pan-STARRS catalogs. The derived "Base-sample" (N = 199,786) and "Quad-sample" (N = 120,418) provide the basis for the examination employed to establish systemic limits within the
Gaia single-
star model. To verify the results and eliminate any bias introduced by employing the WDSS as the basis for the Base and Quad-samples, we exploited an independent sample of
Gaia-2MASS cross-matched audit
stars, the "Audit-sample" (N = 22,371). Only
stars selected at high northern declinations (delta > 60 degrees) were employed for this sample to avoid potential distortions resulting from crowding. All of these samples manifested a -0.75 magnitude offset, indicating the presence of two
stars of equal magnitude, creating a "Detection Gap" across all populations. We conclude, reinforced by a peer-reviewed independent external spectroscopic study, that a 7% floor of global sensitivity exists, representing a limitation of the
Gaia pipeline. This suggests that local
stellar mass density models require a quantifiable correction to accurately reflect the local baryonic mass budget.
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High Energy Astrophysical Phenomena
Upstream neutrino production and delayed jet emission in the blazar GB6 J1542+6129
Emma Kun, Imre Bartos, Breshna Hadi et al. (+7 more)
We present a multimessenger case study of the blazar GB6 J1542+6129, examining whether its multiwavelength behavior is consistent with
neutrino production in a compact region near the central black hole, or with the parsec-scale
radio jet. We perform a multimessenger analysis combining ~17 years of
Fermi-LAT gamma-ray data with ~14 years of VLBI/MOJAVE. These are compared to the temporal properties of a suspected IceCube
neutrino flare with a duration of $147^{+110}_{-25}$ days, enabling a direct test of spatial and causal connections between
neutrino and electromagnetic emission regions. We find that the suspected
neutrino flare appears to precede both a $\gamma$-ray
flare and a pronounced increase in the VLBI core Doppler factor by up to ~1 year. The duration of the post-
flare $\gamma$-ray activity is comparable to that of the
neutrino flare, which, in our framework, is consistent with both signatures originating from a single propagating disturbance whose temporal structure is preserved during the propagation. The gamma-ray spectral energy distribution remains consistent in shape across the full,
flare, and post-
flare intervals, indicating stable particle acceleration conditions. The temporal ordering, taken at face value, places the
neutrino production site upstream of the VLBI core. The observations of GB6 J1542+6129 are consistent with a disturbance-driven, multi-zone scenario in which
neutrinos are produced in a compact,
photon-rich inner region upstream of the parsec-scale VLBI core, plausibly at the coronal region, while the same disturbance later enhances Doppler-boosted leptonic emission once it reaches the
radio core. While the data alone do not strictly establish this scenario on a population level, they show how time-domain multimessenger observations of a single AGN can localize
neutrino emission relative to the parsec-scale
radio jet in a particular source.
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All authors Emma Kun, Imre Bartos, Breshna Hadi, Anna Göblyös, Julia Becker Tjus, Peter L. Biermann, Anna Franckowiak, Francis Halzen, Santiago del Palacio, Claudio Ricci
Solar and Stellar Astrophysics
Magnetic loops in the solar transition region
Zhenghua Huang
Transition region (TR) loops are arcade-like features in the
solar transition region, with temperatures roughly between $2\times10^4$ K and $6\times10^5$ K. They are a fundamental building block of TR, which are results of the coupling between the
magnetic field and the TR
plasma. Their dynamics is closely related to the transport of energy and mass through the TR. Studies on this class of loops since the launch of the Interface Region Imaging Spectrograph (IRIS) have revealed that they are distinct from coronal loops. Observations have revealed that they are associated with many small-scale dynamic phenomena in the TR, from which one can infer the physics behind the energy and mass transfer in a magnetically confined environment at TR temperature. This review summarises the observational results of TR loops, showing their morphology, dynamics,
plasma parameters, their relationship with flux emergence, their heating properties, and their implication in the heating of the
solar atmosphere. This class of
magnetic loops is much less well understood than their coronal counterparts. This review also concludes with several critical questions that need to be answered in the coming era with more advanced observational techniques and more precise and realistic simulations.
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Astrophysics of Galaxies
Life After the Quasar: Overmassive Black Holes and Remnant Ionised Bubbles in and Around Two z~6.6 Galaxies
Romain A. Meyer, Pascal A. Oesch, Callum Witten et al. (+7 more)
Supermassive black holes (SMBH, $M_{\rm{BH}} > 10^8 M_\odot$) powering luminous
quasars already exist one billion years after the Big Bang, yet their connection to their
star-forming host
galaxies, their relation to the general
galaxy population and their contribution to Reionisation remains deeply enigmatic. JWST is finding numerous Active
Galactic Nuclei (AGN) in high-
redshift galaxies with black hole masses that appear to be over-massive compared to their host's
stellar mass, but rarely as massive as those found in luminous
quasars. Here we report JWST/NIRSpec observations revealing overmassive SMBH in two ultra-luminous Lyman-$\alpha$ emitters at $z\sim6.6$ that exhibit rare double-peaked Lyman-alpha profiles. The broad Balmer lines indicate black hole masses $M_{\rm{BH}}\simeq 2\times10^8 M_\odot$, matching that found in faint $z\sim 6-7$
quasars, and very high BH-to-
stellar-mass ratio ($\sim 0.1-0.2$) that exceed the local relation by a factor $\sim$400-800.
Stellar population modelling favours young ages ($<50$ Myr), inconsistent with the sustained average Eddington-rate
accretion required to reach the observed BH masses by $z=6.6$. The double-peak Lyman-$\alpha$ profiles require a large ionised bubble and high photoionisation rate that is consistent with the ionising output of
quasars powered by black holes of similar mass, thus constraining the cessation of the last
quasar episode to $<1$ Myr. We interpret both systems as post-
quasar galaxies in which AGN feedback has delayed
stellar mass assembly, and propose that episodic
quasar activity partially explains the unexpected prevalence of large ionised bubbles deep into the Epoch of Reionisation.
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All authors Romain A. Meyer, Pascal A. Oesch, Callum Witten, Richard S. Elllis, Sarah E. I. Bosman, Fred Davies, Alyssa B. Drake, Nicolas Laporte, Jorryt Matthee, Fabian Walter
Cosmology and Nongalactic Astrophysics
DESI and Gravitational Wave Constraints Challenge Quintessential {\alpha}-Attractor Inflation
Changcheng Jing, George Alestas and Sachiko Kuroyanagi
Quintessential inflation models provide a framework that simultaneously describes inflation and dynamical dark energy, the latter of which has recently received growing support from DESI observations. A distinctive feature of these models is the kination phase after inflation, which enhances
primordial gravitational waves at high frequencies. In this work, we study a class of alpha-attractor quintessential inflation models using a fully numerical approach that follows the scalar-field
evolution from inflation to the dark-energy-dominated era, allowing us to compute with high precision both the dynamics of dark energy and the
primordial gravitational wave spectrum. Using the latest observational data, including DESI and ACT, we constrain the model parameters and show that the model becomes disfavored once constraints from the gravitational-wave contribution to the effective number of relativistic degrees of freedom, {\Delta} Neff, are included. This is because the model predicts a scalar spectral index ns that becomes too small to remain consistent with observations when the gravitational-wave abundance is constrained to stay below the {\Delta} Neff bound. Finally, we present the resulting
primordial gravitational wave power spectrum computed using our constrained parameter values, which highlights prospects for detection by future CMB B-mode experiments at low frequencies and by gravitational-wave interferometer experiments at high frequencies.
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High Energy Astrophysical Phenomena
A bright wideband radio burst from the isolated neutron star 2XMM J104608.7$-$594306
J. Tian, K. M. Rajwade, I. Pastor-Marazuela et al. (+6 more)
We present the discovery of a second coherent
radio burst from the thermally emitting
neutron star 2XMM J104608.7$-$594306 in our follow-up observations with the Murriyang Ultra-Wideband Low receiver. This burst shows complex morphology with multiple components and wideband emission spanning from 704 to 4032MHz. We measured a steep spectral index of $\alpha=-2.18\pm0.16$. Our polarimetric analysis demonstrates that the burst is highly polarised with a linear and circular polarisation fraction of 54% and 22%, respectively. We identified an orthogonal jump in the polarisation position angles of the burst, resembling those seen in
radio pulsars. We compared this burst with the first
radio burst detected from the source with MeerKAT. These two bursts detected in a total of 40 hours on source with MeerKAT and Murriyang, combined, show that 2XMM J104608.7$-$594306 can emit sporadic
radio emission with luminosity jumps comparable to those seen in the bright bursts from SGR 1935+2154. This suggests that previously thought
radio-quiet
neutron stars such as X-ray dim isolated
neutron stars and central compact objects could exhibit rare
radio bursting activity.
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All authors J. Tian, K. M. Rajwade, I. Pastor-Marazuela, B. W. Stappers, M. Caleb, K. Shaji, S. Singh, E. D. Barr, M. Kramer
Instrumentation and Methods for Astrophysics
Beyond Bragg-Mirrors for Gravitational Wave Telescopes: A Fabrication Tolerant Hybrid Metasurface-Bragg Mirror Design
Christian Kranhold, Mika Gaedtke, Markus Walther et al. (+3 more)
Coating thermal noise in high-reflectivity test-mass mirrors is a major limitation for future gravitational-wave detectors, especially in the 10–300 Hz band. ET-Pathfinder therefore requires mirror coatings that combine very high reflectance at 1.55 micrometer with low thermal noise under cryogenic conditions. Conventional dielectric Bragg mirrors provide high reflectance but require thick coatings, whereas metasurface mirrors can reduce coating-related noise but are limited by fabrication tolerances and line-edge roughness. We present a hybrid metasurface–Bragg mirror concept tailored to ET-Pathfinder. The design combines a fabrication-tolerant one-layer metasurface, an anti-resonant Fabry–Perot spacer, and a reduced dielectric Bragg stack. Optical performance is evaluated using full-wave electromagnetic simulations, while fabrication robustness is assessed with a truncated-Gaussian Monte Carlo analysis. Line-edge roughness is included as a systematic edge-smoothing effect. The resulting reflectance distributions are used to determine the minimum Bragg-stack support required to meet system-level specifications. The ideal metasurface exceeds 99.999% reflectance. When fabrication uncertainties and line-edge roughness are included, the metasurface reflectance is limited to about 99.9% at the 95% yield level. The remaining transmission can be compensated by a supporting Bragg stack with as few as seven layer pairs. For this configuration, the hybrid mirror achieves a total thermal displacement noise about one order of magnitude below the projected ET-Pathfinder coating-noise budget. These results show that fabrication-limited metasurface reflectance can be compensated within a hybrid architecture, enabling reduced coating thickness and thermal noise for next-generation gravitational-wave detectors.
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All authors Christian Kranhold, Mika Gaedtke, Markus Walther, Falk Eilenberger, Stefanie Kroker, Thomas Siefke
Earth and Planetary Astrophysics
The Rocky Planet Picture Show: Implementation of Surface Reflection and Emission in $\texttt{POSEIDON}$ with Application to and Interpretation of JWST Data
Elijah Mullens, Ryan J. MacDonald, Marina E. Gemma et al. (+3 more)
The surface characterization of rocky
exoplanets via emission spectroscopy represents a frontier of current (JWST) and future (HWO) observational efforts. Here, we implement new features in the open-source
retrieval code $\texttt{POSEIDON (v1.4)}$ to fully account for an emitting and reflecting planetary surface and an overlying absorbing and scattering atmosphere. We show that realistic rocky surfaces (with wavelength-dependent albedos derived from laboratory measurements) affect emission spectra by imparting mid-infrared diagnostic absorption features, imprinting pseudo-features due to atmospheric transparency windows, and flipping absorption features to emission via surface-atmosphere interface pseudo-temperature inversions. We demonstrate that current JWST spectral data can distinguish between tenuous (low surface pressure, $\leq$ 1 bar) and thick (high surface pressures, $\geq$ 0.1 bar) atmospheres by performing atmosphere + surface
retrievals on published JWST emission data of the rocky worlds TOI-1685b and 55 Cancri e. We then explore JWST MIRI LRS's capability to constrain surface geology of rocky worlds, finding that with sufficient SNR
retrievals can distinguish between granite-like and basaltic surfaces for synthetic
datasets. Finally, we provide an open-source database of lab-derived surface albedos (in the form of directional-hemispherical reflectances), organized by geologic classification and include supplemental tables developed to foster future collaboration between geology and
exoplanet science. Our atmosphere + surface
retrieval technique provides a pathway to probe geologic processes on rocky
exoplanets, showing that upcoming JWST data for terrestrial worlds will enable a deeper exploration of rocky surfaces beyond our
Solar System.
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All authors Elijah Mullens, Ryan J. MacDonald, Marina E. Gemma, Ishan Mishra, Esteban Gazel, Nikole K. Lewis
Astrophysics of Galaxies
Kinematic properties of the TW Hya association
Vadim V. Bobylev
A kinematic analysis of the young
stellar association TWHya has been performed. The components of the displacement
matrix in the Ogorodnikov-Milne linear model have been estimated both graphically and by solving the basic kinematic equations. The association's volume expansion with a coefficient of $K_{xyz}=103\pm9$ km s$^{-1}$ kpc$^{-1}$ was confirmed, which yields a dynamical age estimate of $t=9.7 \pm0.8$ Myr. Using the graphical method, estimates of the association's proper rigid-body rotation parameters $\omega$ around the
galactic axes x and y have been obtained for the first time, with velocity values in the range of 50-70 km s$^{-1}$ kpc$^{-1}$ and errors in their determination of 14-19 km s$^{-1}$ kpc$^{-1}$. However, these values are not confirmed by another method. For example, when solving kinematic equations only using proper motions, all three components of rigid body rotation do not differ significantly from zero, $(\omega_x,\omega_y,\omega_z)=(4,7,11)\pm(5,5,5)$ km s$^{-1}$ kpc$^{-1}$.
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Astrophysics of Galaxies
The NIKA2 Cosmological Legacy Survey in COSMOS: Final 1.2mm and 2mm source catalogs and redshift distribution of dusty star-forming galaxies
C. R. Carvajal-Bohorquez, G. Lagache, A. Beelen et al. (+64 more)
We present the final 1.2mm and 2mm source catalogs and the
redshift distribution of the mm-selected population from the NIKA2 Cosmological Legacy Survey (N2CLS) in the COSMOS field. Our aim is to provide a comprehensive
dataset for studying the physical properties and
evolution of high-
redshift DSFGs. N2CLS covers ~1070 arcmin2 with median noise levels of 315$\mu$Jy and 91$\mu$Jy at 1.2 and 2mm, respectively. Sources are extracted with a S/N threshold of 3.9, ensuring >80% purity. Multi-wavelength counterparts are identified using high-resolution interferometric (sub-)mm data (NOEMA, ALMA) and
radio observations (VLA, MeerKAT).
Redshifts are compiled from spectroscopic and photometric catalogs (e.g., COSMOSWeb). The N2CLS master catalog includes 323 sources detected at >80% purity, with 104 sources detected in both bands, 197 only at 1.2mm, and 22 only at 2mm. Multi-wavelength identifications are secured for ~89% of the sample. The
redshift distribution of 1.2mm sources peaks at 2.8$\pm$0.1, consistent with the epoch of peak
cosmic star formation. In the total sample, we lack
redshift for ~2% of the identified
galaxies, plus 34 sources for which no accurate positional proxy is available, preventing the identification of a multi-wavelength counterpart. We identify 66
galaxies at z>4. The observed
redshift distribution agrees well with the SIDES simulations, while four other
galaxy evolution models are statistically inconsistent with the data. N2CLS is the largest contiguous deep survey to date with this depth and homogeneous coverage. This homogeneous coverage is important, as 25% of N2CLS sources lack a SCUBA2 850 mic counterpart, likely because the strongly non-uniform noise distribution of the SCUBA2 map results in lower sensitivity in parts of the field.The released data products provide a legacy
dataset for studying
dust-obscured
galaxy evolution.
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All authors C. R. Carvajal-Bohorquez, G. Lagache, A. Beelen, R. Adam, P. Ade, H. Ajeddig, S. Amarantidis, P. André, M. Aravena, H. Aussel, A. Benoît, S. Berta, M. Béthermin, L.-J. Bing, A. Bongiovanni, J. Bounmy, O. Bourrion, M. Calvo, Caitlin M.Casey, A. Catalano, D. Chérouvrier, U. Chowdhury, M. De Petris, F.-X. Désert, S. Doyle, E. F. C. Driessen, G. Ejlali, A.L. Faisst, A. Ferragamo, A. Gomez, J. Goupy, C. Hanser, Shuowen Jin, Jeyhan S. Kartaltepe, S. Katsioli, F. Kéruzoré, C. Kramer, B. Ladjelat, S. Leclercq, J.-F. Lestrade, J. F. Macías-Pérez, S. C. Madden, Felix Martinez III, A. Maury, F. Mayet, A. Monfardini, A. Moyer-Anin, M. Muñoz-Echeverría, I. Myserlis, R. Neri, A. Paliwal, L. Perotto, G. Pisano, N. Ponthieu, V. Revéret, A. J. Rigby, A. Ritacco, H. Roussel, F. Ruppin, M. Sánchez-Portal, S. Savorgnano, K. Schuster, A. Sievers, S. Toft, C. Tucker, Jorge A. Zavala, R. Zylka
Cosmology and Nongalactic Astrophysics · Cross-listed from hep-ph
Anisotropy of Cosmic Background Photons from Annihilating/Decaying Dark Matter
Ryosuke Kasuya and Kazunori Nakayama
We provide a detailed formulation for calculating the angular power spectrum of the
cosmic background
photons arising from the dark matter decay or annihilation in a comprehensive manner. We pay particular
attention to the case of dark matter decaying or annihilating into line
photons. It is pointed out that taking account of the energy resolution of the detector is essential to correctly evaluate the angular power spectrum. We apply our formulation to the observational data from infrared, optical, X-ray and gamma-ray
telescopes.
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High Energy Astrophysical Phenomena
Red Quasars: Selecting Candidates in SDSS DR16 and Estimating Their Physical Parameters
M.Yu. Piotrovich, S.D. Buliga and T.M. Natsvlishvili
Using ”color cut” method we obtained from SDSS DR16 catalog 733 red
quasar candidates which amounted to approximately 4% of the objects from the initial sample. Then we estimated the radiative efficiency,
spins, inclination angles, and corresponding new SMBH masses for all 733 objects using three theoretical models. Obtained
spin distributions contain a large percentage of objects with retrograde rotation. It may indicate that these are either very young objects or objects that formed as a result of mergers. The dependencies of the estimated
spin values on SMBH masses show strong correlation with linear fit slope 0.9-1.0 which allows us to assume that red
quasars are likely to contain both Seyferts and NLS1, and that the main mechanism of SMBH mass growth in these objects is disk
accretion.
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High Energy Astrophysical Phenomena
Multi-messenger Constraints on a Primordial Black Hole Origin of the KM3-230213A Event
Yuber F. Perez-Gonzalez
Black holes are expected to end their lifetime in a burst of Hawking radiation, emitting all Standard Model particles at ultra-high energies. The evaporation of a nearby
primordial black hole (PBH) has been proposed as an explanation for the high-energy
neutrino-like event reported by KM3NeT. Such a scenario requires the source to be extremely close to Earth, implying detectable gamma-ray and
cosmic-ray emission. Accounting for the time-dependent field of view of gamma-ray observatories, we find that current experiments should have observed a pre-burst signal, while
neutrino telescopes would also detect lower-energy events before the burst. The absence of such multimessenger signals strongly disfavors a PBH origin of the KM3-230213A event in the minimal 4D Schwarzschild scenario.
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Astrophysics of Galaxies · Cross-listed from physics.chem-ph
High-resolution ro-vibrational and rotational spectroscopy of the open-shell, linear CCH$^+$ ion ($^3\Pi$)
Kim Steenbakkers, Weslley G.D.P. Silva, Oskar Asvany et al. (+5 more)
In this work, we report on the high-resolution infrared spectrum of CCH$^+$ ($^3\Pi$) recorded in the range $3066-3184$~cm$^{-1}$ by means of leak-out spectroscopy. This spectral range covers the fundamental of the CH stretching mode and a highly excited bending vibrational mode. Based on this data (385 ro-vibrational lines), accurate spectroscopic descriptions of the ground and the two vibrationally excited states of CCH$^+$ were obtained. Besides the band origins,
spin-orbit coupling constants, rotational constants, centrifugal distortion constants and $\Lambda$-doubling constants for the ground and excited vibrational states have been derived. This effective
Hamiltonian analysis allowed a search for pure rotational lines of CCH$^+$ in its electronic and vibrational ground state using a two-color millimeterwave - infrared scheme. We observed all rotational transitions from $J^{\prime\prime} = 2$ up to $J^{\prime\prime} = 6$ within the $\Omega = 2$ lowest energy fine structure component with resolved hyperfine splittings. This data has already guided the first detection of CCH$^+$ in space toward the Orion Bar photo-dissociation region, and has the potential to support further astronomical searches for CCH$^+$ either through
radio or infrared spectroscopy, for example with the James Webb Space
Telescope.
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All authors Kim Steenbakkers, Weslley G.D.P. Silva, Oskar Asvany, Gerrit C. Groenenboom, Pavol Jusko, Britta Redlich, Sandra Brünken, Stephan Schlemmer
Astrophysics of Galaxies
XMAGNET – Stir before serving: a Lagrangian perspective on mixing-driven condensation in the intracluster medium
M. Fournier, P. Grete, M. Brüggen et al. (+4 more)
We aim to characterize the thermodynamic and dynamical conditions leading to condensation in cluster cores, and to assess the role of
magnetic fields. We implement a Monte-Carlo tracer particle
algorithm in the GPU-accelerated code AthenaPK, and run a purely hydrodynamical and a magnetohydrodynamical (MHD) simulations of an idealized cool-core cluster. We identify the subset of hot ICM tracers that undergo a transition to the cold phase and reconstruct their histories over a lookback time of $300\,\mathrm{Myr}$ prior to condensation. In both runs, the large majority of tracers transitioning to the cold phase follow a thermodynamic pathway driven by mixing, whereby hot ambient gas is entrained onto low-
entropy seed clumps that subsequently grow into larger clouds and filaments. In the hydrodynamical run, these seeds form mainly via in-situ cooling at the edges of AGN cavities. In the MHD run, the cold gas cycle is more complex: AGN
outflows occasionally shred portions of existing filaments into fragments which are then uplifted, seeding further condensation. In the MHD run, the properties of condensing tracers begin to diverge from the background ICM significantly earlier than in the hydrodynamical run (${\sim}150\,\rm Myr$ before the cooling transition versus ${\sim}30\,\rm Myr$), with vorticity and
magnetic energy growing together. The turbulent Mach number at condensation is also systematically lower than in the hydrodynamical run. We examine the post-condensation
evolution of individual cold structures in the MHD run, namely a massive core filament and two isolated clouds in quiescent regions. We find that
magnetic tension dominates over ram pressure as the primary drag force, significantly reducing the clouds' terminal velocity. Our results demonstrate that
magnetic fields substantially impact the assembly history and kinematic properties of the cold phase in cool-core clusters.
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All authors M. Fournier, P. Grete, M. Brüggen, B. W. O'Shea, G. M. Voit, B. D. Wibking, D. Prasad
High Energy Astrophysical Phenomena · Cross-listed from hep-ph
Bounds on massive graviton-like particles from searches for axion-like particles coupling to photons
Jordan Gué and David d'Enterria
Limits on
spin-0
axion-like-particles (ALPs) coupling to
photons are reinterpreted as constraints on massive
spin-2 graviton-like-particles (GLPs) with universal coupling $\alpha_\text{G}/M_\text{P}$ (where $M_\text{P}$ is the reduced Planck mass) to the Standard Model fields. A minimally model-dependent recasting is performed, exploiting the formally analogous production and detection mechanisms for both particle types, based on the Primakoff and Gertsenshtein effects, i.e.,
photon-
axion/graviton conversion. Constraints originally derived in the ALP mass vs.
photon-coupling plane ($m_\text{a}, g_{\text{a}\gamma}$) are translated into the corresponding bounds in the GLP ($m_\text{G}, \alpha_\text{G}/M_\text{P}$) parameter space over the full mass range, $m_\text{a,G} \approx 10^{-20}$–$10^{14}$eV probed in current and future experimental setups including cavity-based detectors (haloscopes and resonant upconversion devices), helioscopes, magnetometers, optical interferometers, beam dumps, fixed-target, and
collider experiments, as well as astrophysical and cosmological constraints. Generic scenarios are considered in which GLPs are a dark matter candidate and not. Whereas current ALP searches do not set stronger bounds on massive
spin-2 particles than fifth-force tests, future magnetometers, two-beam interferometers, and upconversion experiments have the potential to provide very strong sensitivity, down to $\alpha_\text{G}/M_\text{P} \approx 10^{-32} \text{GeV}^{-1}$, for light graviton-like particles with $m_\text{G}\lesssim 10^{-8}$eV. These future detectors exhibit comparatively greater sensitivity to massive gravitons than to
axions. For massive gravitons at the TeV scale, exclusive diphoton decay searches, employed in ALP studies, offer a complementary approach to standard searches for
spin-2 resonances in other inclusive final states.
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Cosmology and Nongalactic Astrophysics
A consistent formulation of stochastic inflation I: Non-Markovian effects and issues beyond linear perturbations
Diego Cruces and Tomotaka Kuroda
We investigate the origin of non-Markovianity in
stochastic inflation and its implications for nonlinear perturbation theory. In the Schwinger–Keldysh formulation, the noise terms sourcing the infrared (IR) Langevin equations are determined by ultraviolet (UV) modes evolving on top of the
stochastic IR background. Since the UV-mode
evolution generally depends on the past history of the IR sector, the resulting
stochastic dynamics is intrinsically non-Markovian. Working perturbatively, we derive the UV-mode solutions up to second order and decompose the corresponding noise contributions into two parts. The first is a “deterministic” contribution, generated by the functional Taylor expansion of the first-order UV solution around the background trajectory. The second is a genuinely “
stochastic” contribution, originating from terms in the UV-mode equations that are quadratic in the noise variables and are usually neglected in the standard formulation of
stochastic inflation. Under this conventional truncation, the deterministic contribution reduces to a Markovian correction in attractor backgrounds, whereas it could become history dependent in non-attractor phases and gives rise to non-Markovian terms involving integrals over first-order IR perturbations. We finally show that the
stochastic contribution is of the same perturbative order as the deterministic one, which indicate that the conventional truncation is generically inconsistent and quadratic-noise terms may be required for a consistent treatment of nonlinear perturbations in
stochastic inflation. Our analysis clarifies the perturbative structure of non-Markovianity and provides the basis for a systematic treatment of quadratic-noise effects beyond the standard formulation.
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Cosmology and Nongalactic Astrophysics
Measuring $f\sigma_8$ and BAO scale in the Local Universe: a joint real and redshift space analysis from CosmicFlows-4++
C. Franco, H. M. Courtois and A. Bernui
The large-scale clustering of
galaxies encodes both
geometric and dynamical information about the Universe. The
Baryon Acoustic Oscillations (BAO) phenomenon provides a standard ruler that constrains the
cosmic expansion history, while
Redshift Space Distortions (RSD) probe the growth of structure through the peculiar velocity field. In this work, we present a joint analysis of BAO and growth rate parameter, $f\sigma_{8}$, in the Local Universe out to $z = 0.1$, using the $65,331$
galaxy distances of CosmicFlows-4++ database. A distinctive property of this catalogue is the availability of real space
galaxy positions in addition to the
redshift space coordinates. Fitting an empirical model to the measurements we obtain $r_{\rm{BAO}}^{\rm{real}} = 132\pm 8\,h^{-1}\,{\rm Mpc}$ in real space, and $r_{\rm{BAO}}^{z} = 139 \pm 7\,h^{-1}\,{\rm Mpc}$ in
redshift space, at
redshift $z = 0.07$. Modeling the enhancement of the correlation function within the Kaiser formalism, we derive a constraint on the growth rate parameter $f\sigma_8 = 0.344 \pm 0.105$. This analysis demonstrates how the combination of real and
redshift space clustering measurements enables a simultaneous probe of important observables of the large-scale structure. Their joint detection in the same
dataset, therefore, provides a self consistent view of the structure and
evolution of the Local Universe. This study may be used for consistency analyses of upcoming surveys, as DESI and 4MOST, that will also provide data in both real and
redshift space.
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High Energy Astrophysical Phenomena
Maximal mass of neutron stars constrained by neutron star observations
Gábor Kasza and György Wolf
We investigate constraints on the high-density equation of state (EOS) of
neutron star matter by analyzing the probability distributions of the endpoints of mass-radius M(R) sequences within a
Bayesian weighting framework. Starting from two representative hadronic baseline EOSs, SFHo and DD2, matched at higher densities to an extended linear sigma model description and constrained to approach perturbative QCD (pQCD) results, we construct families of causal hybrid EOSs spanning a broad range of stiffness at supranuclear densities. Observational constraints from the binary
neutron-
star merger GW170817, mass-radius measurements from the
Neutron Star Interior Composition Explorer (NICER), and candidate low-mass and mass-gap compact objects are incorporated through
Bayesian likelihood weighting. This approach allows us to determine probability distributions for the maximum
neutron-
star mass M$_{\rm TOV}$ and the corresponding radius R$_{\rm TOV}$, i.e., the endpoints of the M(R) sequences. We find that the maximum-mass distributions are largely determined by observational constraints and show only weak sensitivity to the choice of baseline EOS, favoring values around 2.2-2.3 M$_\odot$ when the most robust constraints are applied. In contrast, the corresponding radius distributions exhibit a stronger dependence on the underlying hadronic EOS, with typical preferred values near $12\pm 1$ km. Additional
tidal-deformability constraints further restrict the allowed parameter space and disfavor very stiff EOS realizations when interpreted together with the possible mass-gap
neutron-
star candidate. Our results demonstrate that endpoint distributions of M(R) sequences provide a sensitive and complementary diagnostic for constraining the high-density behavior of the
neutron-
star EOS within a multimessenger
Bayesian framework.
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Instrumentation and Methods for Astrophysics
Training a neural network to rapidly identify candidate gravitational-wave events in the lower mass gap
Nayyer Raza, Man Leong Chan, Daryl Haggard et al. (+5 more)
The physics governing the boundary between the most massive
neutron stars (NSs) and the least massive black holes (BHs) is currently uncertain, but could potentially be constrained with new observations. While NSs have been observed with masses up to $\sim2~M_{\odot}$, there is a dearth of electromagnetic observations of compact objects in the $\sim2-5~M_{\odot}$ range, known as the lower mass gap. Recent observations of gravitational-wave (GW) signals from binary mergers detected by the LIGO-Virgo-KAGRA (LVK) collaboration indicate that this gap is likely not empty. Rapidly distinguishing whether a candidate GW event has components in this purported mass gap can indicate the likelihood of a detectable electromagnetic counterpart, and thus inform decisions for follow-up observations. In this work we train a neural network model, GWSkyNet-MassGap, that simultaneously predicts the probability that a candidate merger has a component in the lower mass gap ($P_{\mathrm{MassGap}}$) and the probability that it involves a NS ($P_{\mathrm{NS}}$). We find that the model is able to infer information about the source chirp mass to predict $P_{\mathrm{MassGap}}$ and $P_{\mathrm{NS}}$, leading to correct predictions for high-mass mergers with $\mathcal{M}_c\gtrsim15~M_{\odot}$, but less accurate predictions for lower-mass systems which require knowledge of the binary mass ratio to break the mass degeneracy. For candidate events in the first part of LVK's fourth observing run (O4a), the model has a mean prediction error of 9% for $P_{\mathrm{MassGap}}$ and 6% for $P_{\mathrm{NS}}$. The model could be further developed to rapidly predict the source chirp mass for candidate events in future observing runs.
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All authors Nayyer Raza, Man Leong Chan, Daryl Haggard, Ashish Mahabal, Jess McIver, Audrey Durand, Alexandre Larouche, Hadi Moazen
High Energy Astrophysical Phenomena
Random Polarization Position Angle Behaviors across Bursts of Repeating Fast Radio Bursts
Xiaohui Liu, Jiarui Niu, Tiancong Wang et al. (+27 more)
Fast
radio bursts (FRBs), highly polarized, mostly have a nearly constant polarization position angle (PA) during each burst. Their PAs are observed to vary from burst to burst, with the statistical properties remaining stable across different observation sessions. We found that the intrinsic PAs of repeating FRBs are approximately Gaussian distributed, suggesting that the emission likely originates from a localized region within the
neutron star's magnetosphere. A periodicity search of the PA time series using the Lomb-Scargle periodogram reveals no credible periodic signal in the period range from 10 ms to $10^7$ ms, and similar analyses of several active observations also yield null detections. We interpret these properties by extending the rotating vector model to include a dynamically evolving magnetosphere, in which the effective
magnetic axis varies from burst to burst due to
stochastic perturbations. In this framework, the observed PA distributions can naturally arise from
geometric projection effects, and the absence of periodicity reflects the random wandering of the
magnetic axis within a confined region. This scenario provides a natural explanation for both repeating and apparently non-repeating FRBs.
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All authors Xiaohui Liu, Jiarui Niu, Tiancong Wang, Jun-Shuo Zhang, Yuanhong Qu, Jinchen Jiang, Yongkun Zhang, Heng Xu, Dejiang Zhou, Wei-Yang Wang, Weiwei Zhu, Bing Zhang, Xuelei Chen, Xiang-Han Cui, Jinlin Han, Kejia Lee, Di Li, Jiawei Luo, Rui Luo, Chengwei Liang, Chenhui Niu, Wan-Peng Sun, Bojun Wang, Fayin Wang, Pei Wang, Qin Wu, Ziwei Wu, Jiangwei Xu, Yuan-Pei Yang, Shiqian Zhao
Astrophysics of Galaxies
A Universal Dance of Galactic Disks: Ubiquitous Precession and Its Implications
Yuan Wang, Xiong Luo, Huiyuan Wang et al. (+5 more)
Precession is a very common phenomenon for small-scale astronomical objects. However, the precession of
galactic disks, occurring on a scale larger than kilo-parsec, has barely been studied in the literature. Quantifying this precession in observations remains challenging due to the lack of high-resolution dynamical data. Cosmological simulations, where gravitational interactions are self-consistently modeled, offer a unique avenue for investigating disk precession. Leveraging the IllustrisTNG simulations, we trace the
evolution of
spin orientation in Milky Way-like
galaxies over
cosmic time. We find that disk precession is ubiquitous in
galaxies and significantly affects
galaxy evolution. The precession is driven by the external
tidal torque originating from the anisotropic matter distribution within $30\ \mathrm{kpc}$, and is violent at $\mathrm{z} > 1$ and becomes gentler but significant at $\mathrm{z} \sim 0$, when the disks are considered dynamically settled. Disk precession can induce significant cold gas warp, which is often observed in the Milky Way and nearby
galaxies. We predict that the Milky Way is precessing at a rate of $\simeq3-10$ degrees per billion years at current epoch based on its observed warp. Violent precession can heat the orbits of
stars, which may eventually produce prolate elliptical
galaxies. The
tidal torque from central
galaxies can cause the precession of nearby satellite
galaxies and causes their disks to point towards the centrals, which explains the observational radial
alignment. We also find that the precession of accreted cold gas stream, regulated by the
galaxies' torque, is crucial for the
evolution of disk
galaxies.
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All authors Yuan Wang, Xiong Luo, Huiyuan Wang, Enci Wang, Hao Li, Federico Marinacci, Xuejian Shen, Mark Vogelsberger
Solar and Stellar Astrophysics
Exploring RR Lyrae Variable Stars in the Vera C. Rubin Observatory Data Preview 1
Chow-Choong Ngeow and Anupam Bhardwaj
We investigate the properties of known RR Lyrae in the Vera C. Rubin Observatory Data Preview 1 (DP1) fields and compare those with the predictions based on
stellar pulsation models tailored to the Legacy Survey of Space and Time (LSST) filters. The cross-match of the DP1 data with two public variable
star catalogs resulted in $\sim 600$ RR Lyrae with adequate light curve sampling in five (out of seven) DP1 fields. The majority of RR Lyrae are in the 47 Tucanae and Fornax fields. We estimated photometric
metallicities for these RR Lyrae using the theoretical
metallicity-color relation based on $gri$-band data, and find a good agreement with literature values where the light curve sampling is sufficient for fitting template light curves accurately. The distance modulus to all RR Lyrae in DP1 fields were determined using the theoretical period-luminosity-
metallicity (PLZ) relations and the $W_{gr}$ period-Wesenheit-
metallicity (PWZ) relation which has the smallest
metallicity term. The distances based on PWZ relations are in good agreement with the literature values with a mean offset of $0.01\pm0.36$~mag. However, the PLZ-based distance
moduli are systematically large which could be due to the theoretical calibration uncertainties that include evolved horizontal branch models. The predicted period-amplitude relations based on evolved models are also inconsistent with the amplitudes based on DP1 light curves. We conclude that the
metallicity and distance estimates are sensitive to the template fitting to sparsely sampled light curves in DP1 data and future data release will significantly improve these determinations for RR Lyrae
stars.
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