bluuebunny/crossref_metadata_2025_split huggingface dataset:
Supervirial hot phase in Milky Way circumgalactic medium: further evidences
Authors: McClain Rebecca L , Mathur Smita , Das Sanskriti , Krongold Yair , Gupta Anjali 
Published: November 2023

ABSTRACT
Recent discoveries of a supervirial hot phase of the Milky Way circumgalactic medium (CGM) have launched new questions regarding the multiphase structure of the CGM around the Galaxy. We use 1.05 Ms of archival Chandra/high-energy transmission grating observations to characterize highly ionized metal absorption at z = 0 along the line of sight of the quasar NGC 3783. We detect two distinct temperature phases with T$_1 = 5.83^{+0.15}_{-0.07}$ K, warm–hot virial temperature, and T$_2=6.61^{+0.12}_{-0.06}$ K, hot supervirial temperature. The supervirial hot phase coexisting with the warm–hot virial phase has been detected in absorption along only two other sightlines and in one stacking analysis. There is scatter in temperature of the hot as well as warm–hot gas. Similar to previous observations, we detect supersolar abundance ratios of metals in the hot phase, with a Ne/O ratio 2σ above solar mixtures. These new detections continue the mystery of the mechanism behind the supervirial hot phase, but provide evidence that this is a true property of the CGM rather than an isolated observation. The supervirial CGM could hold the key to understanding the physical and chemical history of the Milky Way.
Reconsidering photometric estimation of local star formation environment and its correlation with Type Ia supernova luminosity
Authors: Kim Y-L , Briday M , Copin Y , Hook I , Rigault M , Smith M 
Published: November 2023

ABSTRACT
Recent studies on the environmental dependence of Type Ia supernova (SN Ia) luminosity focus on the local environment where the SN exploded, considering that this is more directly linked to the SN progenitors. However, there is a debate about the local environmental, specifically local star formation rate (SFR), dependence of the SN Ia luminosity. A recent study claims that the dependence is insignificant (0.051 ± 0.020 mag; 2.6σ), based on the local SFR measurement by fitting local ugrizy photometry data. However, we find that this photometric local SFR measurement is inaccurate. We argue this based on the theoretical background of SFR measurement and the methodology used to make that claim with their local ugrizy photometry data, especially due to a limited range of extinction parameters used when fitting the data. Therefore, we reanalyse the same host galaxies with the same fitting code, but with more physically motivated extinction treatments and global ugriz photometry of host galaxies. We estimate global stellar mass and SFR. Then, local star formation environments are inferred by using the method which showed that SNe Ia in globally passive galaxies have locally passive environments, while those in globally star-forming low-mass galaxies have locally star-forming environments. We find that there is significant local environmental dependence of SN Ia luminosities: SNe Ia in locally star-forming environments are 0.072 ± 0.021 mag (3.4σ) fainter than those in locally passive environments, even though SN Ia luminosities have been further corrected by the BEAMS with Bias Corrections method that reduces the size of the dependence.
Swift, NuSTAR, and INTEGRAL observations of the symbiotic X-ray binary IGR J16194-2810
Authors: Bozzo E , Romano P , Ferrigno C , Ducci L 
Published: November 2023

ABSTRACT
We report on a simultaneous observational campaign with both Swift/XRT and NuSTAR targeting the symbiotic X-ray binary (SyXB) IGR J16194-2810. The main goal of the campaign was to investigate the possible presence of cyclotron scattering absorption features in the broad-band spectrum of the source, and help advance our understanding of the process of neutron star formation via the accretion-induced collapse of a white dwarf. The 1–30 keV spectrum of the source, as measured during our campaign, did not reveal the presence of any statistically significant absorption feature. The spectrum could be well described using a model comprising a thermal black-body hot component, most likely emerging from the surface of the accreting neutron star, and a power law with no measurable cut-off energy (and affected by a modest absorption column density). Compared to previous analyses in the literature, we could rule out the presence of a colder thermal component emerging from an accretion disc, compatible with the idea that IGR J16194-2810 is a wind-fed binary (as most of the SyXBs). Our results were strengthened by exploiting the archival XRT and INTEGRAL data, extending the validity of the spectral model used up to 0.3–40 keV and demonstrating that IGR J16194-2810 is unlikely to undergo significant spectral variability over time in the X-ray domain.
Prospective dark matter annihilation signals from the Sagittarius Dwarf Spheroidal
Authors: Venville Thomas A A , Duffy Alan R , Crocker Roland M , Macias Oscar , Tepper-García Thor 
Published: November 2023

ABSTRACT
The Sagittarius Dwarf Spheroidal galaxy (Sgr) is investigated as a target for dark matter (DM) annihilation searches utilizing J-factor distributions calculated directly from a high-resolution hydrodynamic simulation of the infall and tidal disruption of Sgr around the Milky Way. In contrast to past studies, the simulation incorporates DM, stellar and gaseous components for both the Milky Way and the Sgr progenitor galaxy. The simulated distributions account for significant tidal disruption affecting the DM density profile. Our estimate of the J-factor value for Sgr, JSgr = 1.48 × 1010 M$_\odot ^2$ kpc−5 (6.46 × 1016 GeV cm−5), is significantly lower than found in prior studies. This value, while formally a lower limit, is likely close to the true J-factor value for Sgr. It implies a DM cross-section incompatibly large in comparison with existing constraints would be required to attribute recently observed gamma-ray emission from Sgr to DM annihilation. We also calculate a J-factor value using a NFW profile fitted to the simulated DM density distribution to facilitate comparison with past studies. This NFW J-factor value supports the conclusion that most past studies have overestimated the dark matter density of Sgr on small scales. This, together with the fact that the Sgr has recently been shown to emit gamma-rays of astrophysical origin, complicate the use of Sgr in indirect DM detection searches.
Warp and flare of the old Galactic disc as traced by the red clump stars
Authors: Uppal Namita , Ganesh Shashikiran , Schultheis Mathias 
Published: November 2023

ABSTRACT
Our study aims to investigate the outer disc structure of the Milky Way Galaxy using the red clump (RC) stars. We analysed the distribution of the largest sample of RC stars to date, homogeneously covering the entire Galactic plane in the range of 40° ≤ ℓ ≤ 340° and −10° ≤ b ≤ +10°. This sample allows us to model the RC star distribution in the Galactic disc to better constrain the properties of the flare and warp of the Galaxy. Our results show that the scale length of the old stellar disc weakly depends on azimuth, with an average value of 1.95 ± 0.26 kpc. On the other hand, a significant disc flaring is detected, where the scale height of the disc increases from 0.38 kpc in the solar neighbourhood to ∼2.2 kpc at R ≈15 kpc. The flare exhibits a slight asymmetry, with ∼1 kpc more scale height below the Galactic plane as compared to the Northern flare. We also confirm the warping of the outer disc, which can be modelled with Zw = (0.0057 ± 0.0050) [R − (7358 ± 368)(pc)]1.40 ± 0.09sin (ϕ − (− 2${_{.}^{\circ}}$03 ± 0${_{.}^{\circ}}$18)). Our analysis reveals a noticeable north–south asymmetry in the warp, with a greater amplitude observed in the southern direction compared to the northern. Comparing our findings with younger tracers from the literature, we observe an age dependency of both the flare and warp. An increase in flare strength with age suggests the secular evolution of the disc as the preferred mechanism for forming the flare. The increase of the maximum warp amplitude with age indicates that the warp dynamics could be the possible cause of the variation in the warp properties with age.
Planetary entropy production as a thermodynamic constraint for exoplanet habitability
Authors: Petraccone Luigi 
Published: November 2023

ABSTRACT
Any biosphere emerges, lives, and grows producing entropy. Entropy production is a thermodynamic function crucial in the framework of non-equilibrium thermodynamics as it is directly related to the dynamical behaviour of far-from equilibrium systems. The extent of entropy production is proportional to the ability of such systems to dissipate free energy and thus to ‘live’, to evolve, to grow in complexity. Generally, a certain threshold of entropy production must be exceeded for the emergence of complex self-organizing structures. Thus, the entropy production can be considered as the thermodynamic thrust that drives life emergence and evolution. In this perspective, we propose that the value of the planetary entropy production (PEP) can provide a first order estimate of the thermodynamic potential of planetary environment to sustain a complex biosphere. Here we use a simplified approach to evaluate the upper limit to the PEP and to the corresponding free energy as function of stellar temperature and orbital parameters of the planet. We found that only Earth-like planets in the circumstellar habitable zone (CHZ) of G and F stars can have a PEP value higher than the Earth value. Further significant thermodynamic differences exist between the inner and outer edge of the CHZ, with the inner edge being thermodynamically more advantageous for the development of complex biospheres. Interestingly, among the recently proposed habitable exoplanets, the ones belonging to the Hycean planets appear the thermodynamically best candidates.
Towards future challenges in the measurement and modelling of night sky brightness
Authors: Barentine John C , Wallner Stefan , Kocifaj Miroslav 
Published: November 2023

ABSTRACTIn ground-based astronomy, the brightness of the night sky is the limiting factor that determines the efficacy of any particular telescope in terms of detecting faint objects. Proper measurement and monitoring of night sky brightness (NSB) is therefore key to protecting sites of astronomical observatories from light pollution and maximizing their scientific productivity. However, current data sources and modelling approaches exhibit practical shortcomings that significantly limit their utility. By considering the current situation in measuring light pollution, we identify opportunities for improvements. These include defaulting to spatially resolved sky brightness measurements, routinely incorporating spectral information and polarization, and collecting simultaneous meteorological data. Given the acute threat to astronomy posed by rapidly increasing NSB around the world, we argue that the time has come for the standardization of NSB measurement and monitoring methods and protocols.
Measuring distances to galaxies with globular cluster velocity dispersions
Authors: Beasley Michael A , Fahrion Katja , Gvozdenko Anastasia 
Published: November 2023

ABSTRACT
Accurate distances are key to obtaining intrinsic properties of astronomical objects such as luminosity or size. Globular clusters (GCs) follow a well-defined relation between their absolute magnitudes and internal stellar velocity dispersions (σ), offering an independent way to measure distances to their host galaxies via high-resolution spectroscopy. This is reminiscent of the ‘Faber–Jackson’ for elliptical galaxies. However, unlike galaxies, GCs have a very narrow range of mass-to-light ratios and simple star formation histories. Here, we show that the GC MV−log10(σ) relation is linear, whose slope is identical for the Milky Way and M31 GC systems. Based on this, we use 94 Milky Way GCs which have distances from GAIA parallaxes, or proper-motion dispersion profiles to derive a ‘GC velocity dispersion’ distance (GCVD) to M31, obtaining (m − M)0 = 24.51 ± 0.08 (d = 798 ± 28 kpc), in excellent agreement with independent measurements. Combining data for these two galaxies to create a fiducial relation using 296 GCs with high-quality measurements, we obtain a zero-point uncertainty (±0.06 mag) corresponding to a distance uncertainty of $\sim 3~{{\ \rm per\ cent}}$. We then use GCVD to obtain a distance to the giant elliptical galaxy NGC 5128 (Centaurus A), finding (m − M)0 = 27.95 ± 0.09 (d = 3.89 ± 0.16 Mpc). This is in excellent agreement with, and in some cases more precise than, literature estimates from the tip of the red giant branch or surface brightness fluctuations. We apply GCVD to Local Group galaxies with appropriate data and find good agreement with literature values even in cases with only one GC velocity dispersion measurement.
Clouds of Theseus: long-lived molecular clouds are composed of short-lived H2 molecules
Authors: Jeffreson Sarah M R , Semenov Vadim A , Krumholz Mark R 
Published: November 2023

ABSTRACT
We use passive gas tracer particles in an Arepo simulation of a dwarf spiral galaxy to relate the Lagrangian evolution of star-forming gas parcels and their H2 molecules to the evolution of their host giant molecular clouds. We find that the median chemical lifetime of H2 is 4 Myr, with an interquartile range between 2 and 9 Myr. This chemical lifetime is independent of the lifetime of the host molecular cloud, which may extend up to 90 Myr, with around 50 per cent of star formation occurring in longer lived clouds (&gt;25 Myr). The rapid ejection of gas from around young massive stars by early stellar feedback is responsible for the short H2 survival time, driving down the density of the surrounding gas, so that its H2 molecules are dissociated by the interstellar radiation field. This ejection of gas from the H2-dominated state is balanced by the constant accretion of new gas from the galactic environment, constituting a ‘competition model’ for molecular cloud evolution. Gas ejection occurs at a rate that is proportional to the molecular cloud mass, so that the cloud lifetime is determined by the accretion rate, which may be as high as 4 × 104 M⊙ Myr−1 in the longest lived clouds. Our findings therefore resolve the conflict between observations of rapid gas ejection around young massive stars and observations of long-lived molecular clouds in galaxies. We show that the fastest-accreting, longest lived, highest mass clouds drive supernova clustering on sub-cloud scales, which in turn is a key driver of galactic outflows.
Nature of 4FGL J1838.2+3223: A flaring ‘spider’ pulsar candidate
Authors: Zyuzin D A , Kirichenko A Yu , Karpova A V , Shibanov Yu A , Zharikov S V , Gilfanov M R , Perez Tórtola C 
Published: November 2023

ABSTRACT
An unidentified γ-ray source 4FGL J1838.2+3223 has been proposed as a pulsar candidate. We present optical time-series multiband photometry of its likely optical companion obtained with the 2.1-m telescope of Observatorio Astronómico Nacional San Pedro Mártir, Mexico. The observations and the data from the Zwicky Transient Facility revealed the source brightness variability with a period of ≈4.02 h likely associated with the orbital motion of the binary system. The folded light curves have a single sine-like peak per period with an amplitude of about three magnitudes accompanied by fast sporadic flares up to one magnitude level. We reproduce them modelling the companion heating by the pulsar. As a result, the companion side facing the pulsar is strongly heated up to 11300 ± 400 K, while the temperature of its back side is only 2300 ± 700 K. It has a mass of 0.10 ± 0.05 M⊙ and underfills its Roche lobe with a filling factor of $0.60^{+0.10}_{-0.06}$. This implies that 4FGL J1838.2+3223 likely belongs to the ‘spider’ pulsar family. The estimated distance of ≈3.1 kpc is compatible with Gaia results. We detect a flare from the source in X-rays and ultraviolet using Swift archival data and another one in X-rays in the eROSITA all-sky survey. Both flares have X-ray luminosity of ∼1034 erg s−1 which is two orders of magnitude higher than the upper limit in quiescence obtained from eROSITA assuming spectral shape typical for spider pulsars. If the spider interpretation is correct, these flares are among the strongest observed from non-accreting spider pulsars.
Unipolar solar flares as a manifestation of ‘topological’ magnetic reconnection
Authors: Dumin Yurii V , Somov Boris V 
Published: November 2023

ABSTRACT
Solar flares – the most prominent manifestation of solar activity – typically manifest themselves as a single or a set of luminous arcs (magnetic flux tubes) rooted in regions of opposite polarity in the photosphere. However, a careful analysis of archival data from the Hinode satellite reveals occasional surprising cases of flaring arcs whose footpoints belong to regions of the same polarity or to areas without any appreciable magnetic field. Despite the counterintuitive nature of this phenomenon, it can be reasonably interpreted in the framework of the so-called ‘topological model’ of magnetic reconnection, whereby a magnetic null point is formed owing to a specific superposition of influences from remote sources rather than by local current systems. As a result, the energy release propagates along the separator of a flipping two-dome structure rather than along a fixed magnetic field line. Therefore, the luminous arc no longer needs to be associated immediately with the magnetic sources. Here, we report observational cases of the above-mentioned type and provide a theoretical model and numerical simulations.
Higher beta-hydroxybutyrate ketone levels associated with a slower kidney function decline in ADPKD
Authors: Knol Martine G E , Bais Thomas , Geertsema Paul , Connelly Margery A , Bakker Stephan J L , Gansevoort Ron T , van Gastel Maatje D A ,   the DIPAK Consortium, Drenth J P H , de Fijter J W , Peters D J M , Salih M , Hoorn E J , Nijenhuis T , Meijer E 
Published: November 2023

ABSTRACT

Background
Dysregulated energy metabolism is a recently discovered key feature of autosomal dominant polycystic kidney disease (ADPKD). Cystic cells depend on glucose and are poorly able to use other energy sources such as ketone bodies. Raising ketone body concentration reduced disease progression in animal models of polycystic kidney diseases. Therefore, we hypothesized that higher endogenous plasma beta-hydroxybutyrate (BHB) concentrations are associated with reduced disease progression in patients with ADPKD.

Methods
We analyzed data from 670 patients with ADPKD participating in the Developing Intervention Strategies to Halt Progression of ADPKD (DIPAK) cohort, a multi-center prospective observational cohort study. BHB was measured at baseline using nuclear magnetic resonance spectroscopy. Participants were excluded if they had type 2 diabetes, were using disease-modifying drugs (e.g. tolvaptan, somatostatin analogs), were not fasting or had missing BHB levels, leaving 521 participants for the analyses. Linear regression analyses were used to study cross-sectional associations and linear mixed-effect modeling for longitudinal associations.

Results
Of the participants, 61% were female, with an age of 47.3 ± 11.8 years, a height-adjusted total kidney volume (htTKV) of 834 [interquartile range (IQR) 495–1327] mL/m and an estimated glomerular filtration rate (eGFR) of 63.3 ± 28.9 mL/min/1.73 m2. The median concentration of BHB was 94 (IQR 68–147) µmol/L. Cross-sectionally, BHB was associated neither with eGFR nor with htTKV. Longitudinally, BHB was positively associated with eGFR slope {B = 0.35 mL/min/1.73 m2 [95% confidence interval (CI) 0.09 to 0.61], P = .007}, but not with kidney growth. After adjustment for potential confounders, every doubling in BHB concentration was associated with an improvement in the annual rate of eGFR by 0.33 mL/min/1.73 m2 (95% CI 0.09 to 0.57, P = .008).

Conclusion
These observational analyses support the hypothesis that interventions that raise BHB concentration could reduce the rate of kidney function decline in patients with ADPKD.
Evolution of Influenza A(H3N2) Viruses in 2 Consecutive Seasons of Genomic Surveillance, 2021–2023
Authors: Fall Amary , Han Lijie , Yunker Madeline , Gong Yu-Nong , Li Tai-Jung , Norton Julie M , Abdullah Omar , Rothman Richard E , Fenstermacher Katherine Z J , Morris C Paul , Pekosz Andrew , Klein Eili , Mostafa Heba H 
Published: November 2023

Abstract

Background
The circulation and the genomic evolution of influenza A(H3N2) viruses during the 2021/2022 and 2022/2023 seasons were studied and associated with infection outcomes.

Methods
Remnant influenza A–positive samples following standard-of-care testing from patients across the Johns Hopkins Health System (JHHS) were used for the study. Samples were randomly selected for whole viral genome sequencing. The sequence-based pEpitope model was used to estimate the predicted vaccine efficacy (pVE) for circulating H3N2 viruses. Clinical data were collected and associated with viral genomic data.

Results
A total of 121 683 respiratory specimens were tested for influenza at JHHS between 1 September 2021 and 31 December 2022. Among them, 6071 (4.99%) tested positive for influenza A. Of these, 805 samples were randomly selected for sequencing, with hemagglutinin (HA) segments characterized for 610 samples. Among the characterized samples, 581 were H3N2 (95.2%). Phylogenetic analysis of HA segments revealed the exclusive circulation of H3N2 viruses with HA segments of the 3C.2a1b.2a.2 clade. Analysis of a total of 445 complete H3N2 genomes revealed reassortments; 200 of 227 of the 2022/2023 season genomes (88.1%) were found to have reassorted with clade 3C.2a1b.1a. The pVE was estimated to be −42.53% for the 2021/2022 season and 30.27% for the 2022/2023 season. No differences in clinical presentations or admissions were observed between the 2 seasons.

Conclusions
The increased numbers of cases and genomic diversity of influenza A(H3N2) during the 2022/2023 season were not associated with a change in disease severity compared to the previous influenza season.
Characterizing juvenile dispersal dynamics of invasive Barred Owls: Implications for management
Authors: Watson Whitney A , Hofstadter Daniel F , Jones Gavin M , Kramer H Anu , Kryshak Nicholas F , Zulla Ceeanna J , Whitmore Sheila A , O’Rourke Virginia , Keane John J , Gutiérrez R J , Peery M Zachariah 
Published: November 2023

Abstract
Characterizing natal dispersal can help manage the spread of invasive species expanding their ranges in response to land use and climate change. The Barred Owl (Strix varia) is a prominent example of an apex predator undergoing a rapid range expansion, having spread from eastern to western North America where it is now hyperabundant—threatening the Northern Spotted Owl (Strix occidentalis caurina) with extinction and potentially endangering many other native species. We attached satellite tags to 31 Barred Owl juveniles at the southern leading edge of the Barred Owl’s expanding range in California to characterize natal dispersal patterns and inform management. Juveniles traveled up to 100 km from natal territories and experienced high mortality (annual survival = 0.204). At landscape scales, juveniles preferentially used forests, shrublands, and lower elevations during dispersal and avoided grasslands and burned areas. At finer scales, juveniles preferred shorter (younger) forests, lower elevations, and drainages, and avoided unforested areas. Our results suggest that the Barred Owl range expansion is being driven primarily by high reproductive rates and densities despite low juvenile survival rates and dispersal through putatively suboptimal younger forests as a result of exclusion from high-quality habitat by territorial individuals. These findings also point to several strategies for conserving Spotted Owls and other native species in the Barred Owl’s expanded range, including: (1) creating and maintaining Barred Owl-free reserves bounded by open or high elevation areas, (2) creating reserves large enough to reduce immigration by long-distance dispersers, and (3) removing Barred Owls from large riparian corridors.