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Solar flares are regularly observed in extreme-ultraviolet soft X-rays (SXRs) and hard X-rays (HXRs). However, those in near- and mid-ultraviolet are sparse. The Solar Ultraviolet Imaging Telescope (SUIT) on board the Aditya-L1, launched on 2023 September 2, provides regular observations in the 200–400 nm wavelength range through 11 filters. Here, we report the observation of the X6.3 flare on 2024 February 22 using eight narrowband (NB) filters of SUIT. We have also used co-spatiotemporal observations from Solar Dynamics Observatory/Atmospheric Imaging Assembly (SDO/AIA), Solar Orbiter/STIX, GONG H α , Aditya-L1/SoLEXS, and GOES. We obtained light curves over the flaring region from AIA 1600 and 1700 Å and GONG H α and compared them with the disk-integrated light curve obtained from GOES and SoLEXS SXRs and STIX HXRs. We find that the flare peaks in SUIT NB01, NB03, NB04, and NB08 filters simultaneously with HXRs 1600 and 1700 Å, along with the peak temperature obtained from SoLEXS. In contrast, in NB02 and NB05, the flare peaks ∼2 min later than the HXR peak, while in NB06 and NB07, the flare peaks ∼3 min after the GOES SXR peak. To the best of our knowledge, this is the first observation of a flare in these wavelengths (except in NB03, NB04, and NB05). Moreover, for the first time, we show the presence of a bright kernel in NB02. These results demonstrate the capabilities of SUIT observations in flare studies.

Most stripped-envelope supernova progenitors are thought to be formed through binary interaction, losing hydrogen and/or helium from their outer layers. Ultrastripped supernovae are an emerging class of transient that are expected to be produced through envelope stripping by a neutron star companion. However, relatively few examples are known, and the outcomes of such systems can be diverse and are poorly understood at present. Here we present spectroscopic observations and high-cadence, multiband photometry of SN 2023zaw, a rapidly evolving supernova with a low ejecta mass. SN 2023zaw was discovered in a nearby spiral galaxy at D = 39.7 Mpc. It has significant Milky Way extinction, E ( B − V ) _MW = 0.21, and significant (but uncertain) host extinction. Bayesian evidence comparison reveals that nickel is not the only power source and that an additional energy source is required to explain our observations. Our models suggest that an ejecta mass of M _ej ∼ 0.07 M _⊙ and a synthesised nickel mass of M _Ni ∼ 0.007 M _⊙ are required to explain the observations. We find that additional heating from a central engine, or interaction with circumstellar material, can power the early light curve.

The study presents the first electron density profile of the Lunar ionosphere when the Moon is inside the geomagnetic tail region. This observation used S -band telemetry and telecommand radio signals in a two-way radio occultation experiment from Chandrayaan-2 (CH-2) orbiting the Moon. The radio signals were tracked using an 18 m diameter antenna at the Indian Deep Space Network (IDSN). The IDSN served as an active source for generating and receiving the radio signal, while the onboard oscillator on CH-2 was used as a passive receiver and transmitter. The transmitted radio signal passed twice through the lunar plasma medium before reaching the receiver end. The study found a high electron density of approximately ∼2.5 × 10 ^4 per cm ^−3 close to the surface of the Moon. Three-dimensional lunar ionospheric model simulations show that to achieve such high plasma density, the plasma should be in photochemical equilibrium, which is possible inside the geomagnetic tail only in the presence of lunar crustal magnetic fields. The model also introduced a localized reduction in Ar and Ne neutral density to align with previous observations near the lunar pole.

On 2024 May 27, the Wide-field X-ray Telescope on board the Space Sciences, University of Chinese Academy of Einstein Probe (EP) mission detected enhanced X-ray emission from a new transient source in the Small Magellanic Cloud during its commissioning phase. Prompt follow-up with the EP Follow-up X-ray Telescope, the Swift X-ray Telescope. and NICER have revealed a very soft, thermally emitting source ( kT ~ 0.1 keV at the outburst peak) with an X-ray luminosity of L ~ 4 × 10 ^38 erg s ^−1 , labeled EP J005245.1−722843. This supersoft outburst faded very quickly in a week's time. Several emission lines and absorption edges were present in the X-ray spectrum, including deep nitrogen (0.67 keV) and oxygen (0.87 keV) absorption edges. The X-ray emission resembles the supersoft source phase of typical nova outbursts from an accreting white dwarf (WD) in a binary system, despite the X-ray source being historically associated with an O9-B0e massive star exhibiting a 17.55 day periodicity in the optical band. The discovery of this supersoft outburst suggests that EP J005245.1−722843 is a BeWD X-ray binary: an elusive evolutionary stage where two main-sequence massive stars have undergone a common envelope phase and experienced at least two episodes of mass transfer. In addition, the very short duration of the outburst and the presence of Ne features hint at a rather massive, i.e., close to the Chandrasekhar limit, Ne–O WD in the system.

Fast radio bursts (FRBs) are millisecond-duration pulses occurring at cosmological distances with a mysterious origin. Observations show that at least some FRBs are produced by magnetars. All magnetar-powered FRB models require some triggering mechanisms, among which the most popular is the cracking of the crust of a neutron star, which is called a starquake. However, so far there has been no decisive evidence for this speculation. Here we report the energy functions of the three most active repeating FRBs, which show a universal break around 10 ^38 erg. Such a break is similar to that of the frequency–magnitude relationship of earthquakes. The break, and the change in the power-law indices below and above it, can be well understood within the framework of FRBs triggered by starquakes in the magnetar models. The seed of weak FRBs can grow both on the magnetar surface and in the deeper crust. In contrast, the triggering of strong FRBs is confined by the crustal thickness, and the seed of strong FRBs can only grow on the surface. This difference in dimensionality causes a break in the scaling properties from weak to strong FRBs, occurring at a point where the penetration depth of starquakes equals the crustal thickness. Our result, together with the earthquake-like temporal properties of these FRBs, strongly supports the idea that FRBs are triggered by starquakes, providing a new opportunity to study the physical properties of the crust of a neutron star.

The discovery and localization of FRB 20240209A by the Canadian Hydrogen Intensity Mapping Fast Radio Burst (CHIME/FRB) experiment marks the first repeating FRB localized with the CHIME/FRB Outriggers and adds to the small sample of repeating FRBs with associated host galaxies. Here we present Keck and Gemini observations of the host that reveal a redshift z = 0.1384 ± 0.0004. We perform stellar population modeling to jointly fit the optical through mid-IR data of the host and infer a median stellar mass log( M _* / M _⊙ ) = 11.35 ± 0.01 and a mass-weighted stellar population age ~11 Gyr, corresponding to the most massive and oldest FRB host discovered to date. Coupled with a star formation rate

Fast X-ray transients (FXTs) are extragalactic bursts of X-rays first identified in archival X-ray data and are now routinely discovered in real time by the Einstein Probe, which is continuously surveying the night sky in the soft (0.5–4 keV) X-ray regime. In this Letter, we report the discovery of the second optical counterpart (AT 2024gsa) to an FXT (EP 240414a). EP 240414a is located at a projected radial separation of 27 kpc from its likely host galaxy at z = 0.4018 ± 0.0010. The optical light curve of AT 2024gsa displays three distinct components. The initial decay from our first observation is followed by a rebrightening episode, displaying a rapid rise in luminosity to an absolute magnitude M _r ∼ −21 after two rest-frame days. While the early optical luminosity and decline rate are similar to those of luminous fast blue optical transients, the color temperature of AT 2024gsa is distinctly red and we show that the peak flux is inconsistent with a thermal origin. The third component peaks at M _i ∼ −19 at ≳16 rest-frame days post-FXT, and is compatible with an emerging supernova. We fit the riz -band data with a series of power laws and find that the decaying components are in agreement with gamma-ray burst afterglow models, and that the rebrightening may originate from refreshed shocks. By considering EP 240414a in context with all previously reported known-redshift FXT events, we propose that Einstein Probe FXT discoveries may predominantly result from (high-redshift) gamma-ray bursts, and thus appear to be distinct from the previously discovered lower-redshift, lower-luminosity population of FXTs.

We present multifrequency (5–345 GHz) and multiresolution radio observations of 1ES 1927+654, widely considered one of the most unusual and extreme changing-look active galactic nuclei (CL-AGNs). The source was first designated a CL-AGN after an optical outburst in late 2017 and has since displayed considerable changes in X-ray emission, including the destruction and rebuilding of the X-ray corona in 2019–2020. Radio observations prior to 2023 show a faint and compact radio source typical of a radio-quiet AGN. Starting in 2023 February, 1ES 1927+654 began exhibiting a radio flare with a steep exponential rise, reaching a peak 60 times previous flux levels, and has maintained this higher level of radio emission for over a year to date. The 5–23 GHz spectrum is broadly similar to gigahertz-peaked radio sources, which are understood to be young radio jets less than ∼1000 yr old. Recent high-resolution Very Long Baseline Array observations at 23.5 GHz now show resolved extensions on either side of the core, with a separation of ∼0.15 pc, consistent with a new and mildly relativistic bipolar outflow. A steady increase in the soft X-ray band (0.3–2 keV) concurrent with the radio may be consistent with jet-driven shocked gas, though further observations are needed to test alternate scenarios. This source joins a growing number of CL-AGNs and tidal disruption events that show late-time radio activity, years after the initial outburst.

This Letter reports 12 novel spectroscopic detections of warm circumstellar dust orbiting polluted white dwarfs using the JWST Mid-Infrared Instrument (MIRI). The disks span 2 orders of magnitude in fractional infrared brightness and more than double the number of white dwarf dust spectra available for mineralogical study. Among the highlights are (i) the two most subtle infrared excesses yet detected, (ii) the strongest silicate emission features known for any debris disk orbiting any main-sequence or white dwarf star, (iii) one disk with a thermal continuum but no silicate emission, and (iv) three sources with likely spectral signatures of silica glass. The near ubiquity of solid-state emission requires small dust grains that are optically thin and thus must be replenished on year-to-decade timescales by ongoing collisions. The disk exhibiting a featureless continuum can only be fit by dust temperatures in excess of 2000 K, implying highly refractory material comprised of large particles, or non-silicate mineral species. If confirmed, the glassy silica orbiting three stars could be indicative of high-temperature processes and subsequent rapid cooling, such as occur in high-velocity impacts or vulcanism. These detections have been enabled by the unprecedented sensitivity of MIRI low-resolution spectrometer spectroscopy and highlight the capability and potential for further observations in future cycles.

The light curves of old G dwarfs obtained in the visible and near-infrared wavelength ranges are highly irregular. This significantly complicates the detectability of the rotation periods of stars similar to the Sun in large photometric surveys, such as Kepler and TESS. In this study, we show that light curves collected in the ultraviolet (UV) wavelength range are much more suitable for measuring rotation periods. Motivated by the observation that the Sun’s rotational period is clearly discernible in the UV part of the spectrum, we study the wavelength dependence of the rotational period detectability. We employ the Spectral and Total Irradiance Reconstructions model to characterize the detectability of the solar rotation period across various wavelengths using the autocorrelation technique. We find that at wavelengths above 400 nm, the probability of detecting the rotation period of the Sun observed at a random phase of its activity cycle is approximately 20%. The probability increases to 80% at wavelengths shorter than 400 nm. These findings underscore the importance of UV stellar photometry.

Assessing the prevalence of atmospheres on rocky planets around M-dwarf stars is a top priority of exoplanet science. High-energy activity from M dwarfs can destroy the atmospheres of these planets, which could explain the lack of atmosphere detections to date. Volcanic outgassing has been proposed as a mechanism to replenish the atmospheres of tidally heated rocky planets. L 98-59 b, a sub-Earth transiting a nearby M dwarf, was recently identified as the most promising exoplanet to detect a volcanic atmosphere. We present the transmission spectrum of L 98-59 b from four transits observed with JWST NIRSpec G395H. Although the airless model provides an adequate fit to the data based on its χ ^2 , an SO _2 atmosphere is preferred by 3.6 σ over a flat line in terms of the Bayesian evidence. Such an atmosphere would likely be in a steady state where volcanism balances escape. If so, L 98-59 b must experience at least eight times as much volcanism and tidal heating per unit mass as Io. If volcanism is driven by runaway melting of the mantle, we predict the existence of a subsurface magma ocean in L 98-59 b extending up to R _p ∼ 60%–90%. An SO _2 -rich volcanic atmosphere on L 98-59 b would be indicative of an oxidized mantle with an oxygen fugacity of f O _2 > IW + 2.7, and it would imply that L 98-59 b must have retained some of its volatile endowment despite its proximity to its star. Our findings suggest that volcanism may revive secondary atmospheres on tidally heated rocky planets around M dwarfs.

We present the discovery of a large extended radio jet associated with the extremely radio-loud quasar J1601+3102 at z ∼​​​​​ 5 from subarcsecond resolution imaging at 144 MHz with the International LOFAR Telescope. These large radio lobes have been argued to remain elusive at z > 4 due to energy losses in the synchrotron emitting plasma as a result of scattering of the strong cosmic microwave background at these high redshifts. Nonetheless, the 0 $\mathop{.}\limits^{{\rm{^{\prime} }}{\rm{^{\prime} }}}$ 3 resolution radio image of J1601+3102 reveals a northern and a southern radio lobe located at 9 and 57 kpc from the optical quasar, respectively. The measured jet size of 66 kpc makes J1601+3102 the largest extended radio jet at z > 4 to date. However, it is expected to have an even larger physical size in reality due to projection effects brought about by the viewing angle. Furthermore, we observe the rest-frame UV spectrum of J1601+3102 with Gemini/GNIRS to examine its black hole properties, which results in a mass of 4.5 × 10 ^8 M _⊙ with an Eddington luminosity ratio of 0.45. The black hole mass is relatively low compared to the known high- z quasar population, which suggests that a high black hole mass is not strictly necessary to generate a powerful jet. This discovery of the first ∼​​​​​100 kpc radio jet at z > 4 shows that these objects exist despite energy losses from inverse Compton scattering and can put invaluable constraints on the formation of the first radio-loud sources in the early Universe.

We present the results of our multiwavelength (X-ray to radio) follow-up campaign of the Einstein Probe transient EP240408a. The initial 10 s trigger displayed bright soft X-ray (0.5–4 keV) radiation with peak luminosity L _X ≳ 10 ^49 (10 ^50 ) erg s ^−1 for an assumed redshift z ≳ 0.5 (2.0). The Neil Gehrels Swift Observatory and Neutron star Interior Composition ExploreR discovered a fading X-ray counterpart lasting for ∼5 days (observer frame), which showed a long-lived (∼4 days) plateau-like emission ( t ^−0.5 ) before a sharp power-law decline ( t ^−7 ). The plateau emission was in excess of L _X ≳ 10 ^46 (10 ^47 ) erg s ^−1 at z ≳ 0.5 (2.0). Deep optical and radio observations resulted in nondetections of the transient. Our observations with Gemini South revealed a faint potential host galaxy ( r ≈ 24 AB mag) near the edge of the X-ray localization. The faint candidate host, and lack of other potential hosts ( r ≳ 26 AB mag; J ≳ 23 AB mag), imply a higher redshift origin ( z ≳ 0.5), which produces extreme X-ray properties that are inconsistent with many known extragalactic transient classes. In particular, the lack of a bright gamma-ray counterpart, with the isotropic-equivalent energy (10–10,000 keV) constrained by GECam and Konus-Wind to E _γ _,iso ≲ 4 × 10 ^50 (6 × 10 ^51 ) erg at z ≈ 0.5 (2.0), conflicts with known gamma-ray bursts of similar X-ray luminosities. We therefore favor a jetted tidal disruption event as the progenitor of EP240408a at z ≳ 1.0, possibly caused by the disruption of a white dwarf by an intermediate-mass black hole. The alternative is that EP240408a may represent a new, previously unknown class of transient.

We present a comprehensive analysis of 66 interplanetary shocks observed by the Parker Solar Probe between 2018 November and 2024 January. Among these, 33 events fulfilled the Rankine–Hugoniot (R-H) conditions, ensuring reliable asymptotic plasma parameter solutions. The remaining 33 events could not be confirmed by the standard R-H approach—potentially including wave-like structures—yet were analyzed via averaging and mixed-data methods to obtain robust shock parameters. Utilizing our ShOck Detection Algorithm database, the shocks are categorized into fast-forward, fast-reverse, slow-forward, and slow-reverse types. We investigate the statistical properties of these shocks, focusing on correlations between key parameters—magnetic field compression, density compression, shock normal angle, and change in velocity—and heliocentric distance. Significant positive correlations are identified between heliocentric distance and both magnetic field compression and density compression, suggesting that shocks strengthen as they propagate away from the Sun, largely due to the high local magnetosonic speeds closer to the Sun that can suppress shock formation except in extremely fast events. These findings provide new insights into the dynamic processes governing shock evolution in the inner heliosphere, including scenarios where the near-radial magnetic field geometry may lead to predominantly quasi-parallel shock configurations and thus affect near-Sun particle acceleration efficiency. We also provide strong evidence for the existence of slow-mode shocks near the Sun, contributing to the understanding of shock formation and evolution in the inner heliosphere.

We present the first X-ray polarization measurements of GX 339–4. IXPE observed this source twice during its 2023–2024 outburst, once in the soft-intermediate state and again during a soft state. The observation taken during the intermediate state shows a significant (4 σ ) polarization degree P _X = 1.3% ± 0.3% and polarization angle θ _X = −74° ± 7° only in the 3–8 keV band. FORS2 at the Very Large Telescope observed the source simultaneously, detecting optical polarization in the B , V , R , and I bands (between ∼0.1% and ∼0.7%), all roughly aligned with the X-ray polarization. We also detect a discrete jet knot from radio observations with the Australia Telescope Compact Array taken later in time; this knot would have been ejected from the system around the same time as the hard-to-soft X-ray state transition, and a bright radio flare occurred ∼3 months earlier. The proper motion of the jet knot provides a direct measurement of the jet orientation angle on the plane of the sky at the time of the ejection. We find that both the X-ray and optical polarization angles are aligned with the direction of the ballistic jet.

The NANOGrav 15 yr data provide compelling evidence for a stochastic gravitational-wave (GW) background at nanohertz frequencies. The simplest model-independent approach to characterizing the frequency spectrum of this signal consists of a simple power-law fit involving two parameters: an amplitude A and a spectral index γ . In this Letter, we consider the next logical step beyond this minimal spectral model, allowing for a running (i.e., logarithmic frequency dependence) of the spectral index, ${\gamma }_{{\rm{run}}}(f)=\gamma +\beta \mathrm{ln}\left(f/{f}_{{\rm{ref}}}\right)$ . We fit this running-power-law (RPL) model to the NANOGrav 15 yr data and perform a Bayesian model comparison with the minimal constant-power-law (CPL) model, which results in a 95% credible interval for the parameter β consistent with no running, $\beta \in \left[-0.80,2.96\right]$ , and an inconclusive Bayes factor, ${ \mathcal B }\left({\rm{RPL}}\,{\rm{versus}}\,{\rm{CPL}}\right)=0.69\pm 0.01$ . We thus conclude that, at present, the minimal CPL model still suffices to adequately describe the NANOGrav signal; however, future data sets may well lead to a measurement of nonzero β . Finally, we interpret the RPL model as a description of primordial GWs generated during cosmic inflation, which allows us to combine our results with upper limits from Big Bang nucleosynthesis, the cosmic microwave background, and LIGO–Virgo–KAGRA.

Recent solar observations of bipolar light bridges (BLBs) in sunspots have, in a few individual cases, revealed magnetic fields up to 8.2 kG, which is at least twice as strong as typical values measured in sunspot umbrae. However, the small number of such observations hinted that such strong fields in these bright photospheric features that separate two opposite-polarity umbrae are a rare phenomenon. We determine the field strength in a large sample of BLBs with the aim of establishing how prevalent such strong fields are in BLBs. We apply a state-of-the-art inversion technique that accounts for the degradation of the data by the intrinsic point-spread function of the telescope, to the so far largest set of spectropolarimetric observations, by Hinode/Solar Optical Telescope spectropolarimeter, of sunspots containing BLBs. We identified 98 individual BLBs within 51 distinct sunspot groups. Since 66.3% of the BLBs were observed multiple times, a total of 630 spectropolarimetric scans of these 98 BLBs were analyzed. All analyzed BLBs contain magnetic fields stronger than 4.5 kG at unit optical depth. The field strengths decrease faster with height than the fields in umbrae and penumbrae. BLBs display a unique continuum intensity and field strength combination, forming a population well separated from umbrae and the penumbrae. The high brightness of BLBs in spite of their very strong magnetic fields points to the presence of a so far largely unexplored regime of magnetoconvection.

Robust inference of galaxy stellar masses from photometry is crucial for constraints on galaxy assembly across cosmic time. Here, we test a commonly used spectral energy distribution (SED) fitting code using simulated galaxies from the S phinx ^20 cosmological radiation hydrodynamics simulation with JWST NIRCam photometry forward-modeled with radiative transfer. Fitting the synthetic photometry with various star formation history models, we show that recovered stellar masses are, encouragingly, generally robust to within a factor of ∼3 for galaxies in the range M _⋆ ∼ 10 ^7 −10 ^9 M _⊙ at z = 5−10. These results are in stark contrast to recent work claiming that stellar masses can be underestimated by as much as an order of magnitude in these mass and redshift ranges. However, while >90% of masses are recovered to within 0.5 dex, there are notable systematic trends, with stellar masses typically overestimated for low-mass galaxies ( M _⋆ ≲ 10 ^8 M _⊙ ) and slightly underestimated for high-mass galaxies ( M _⋆ ≳ 10 ^9 M _⊙ ). We demonstrate that these trends arise due to the SED fitting code poorly modeling the impact of strong emission lines on broadband photometry. These systematic trends, which exist for all star formation history parameterizations tested, have a tilting effect on the inferred stellar mass function, with the number densities of massive galaxies underestimated (particularly at the lowest redshifts studied) and the number densities of lower-mass galaxies typically overestimated. Overall, this work suggests that we should be optimistic about our ability to infer the masses of high- z galaxies observed with JWST (notwithstanding contamination from active galactic nuclei) but careful when modeling the impact of strong emission lines on broadband photometry.

The assembly of supermassive black hole (SMBH) mass ( M _• ) and stellar mass ( M _* ) in galaxies can be studied via the redshift evolution of the M _• – M _* relation, but the ways in which selection bias and physical assembly channels affect this evolution are uncertain. To address this, we compare the M _• – M _* relation for local massive ( M _* > 10 ^10.5 M _⊙ ) quiescent early-type galaxies (ETGs) to that for massive ETGs hosting active galactic nuclei (AGN) at z ∼ 0.8. The restrictions on stellar mass and galaxy type limit the assembly channels that may connect the two relations. For the local sample we find $\mathrm{log}({M}_{\bullet })=8.80+1.10(\mathrm{log}{M}_{* }-11)$ , in line with prior work. For the z ∼ 0.8 sample we find a bias-corrected relation: $\mathrm{log}({M}_{\bullet })=7.80+1.25(\mathrm{log}{M}_{* }-11)$ . We show, however, that this relation depends on the stellar and SMBH mass functions used to compute the selection bias, the virial relation, the virial factor, and the active fraction, which together introduce uncertainty of up to ​​​​​​∼0.6 dex in the z ∼ 0.8 relation. Adopting reasonable choices of these parameters then our z ∼ 0.8 relation lies above that for z ∼ 0 AGN by ∼0.5 dex, but below our z ∼ 0 ETG relation by 0.4–1 dex in SMBH mass. We discuss possible sources of this offset, including further bias corrections, “downsizing” in SMBH mass assembly, and preferential SMBH growth. Our results highlight the need to reduce uncertainties from selection and measurement bias in SMBH and stellar masses at all redshifts.

Electrodeposition of CdTeSe thin films with two-electrode electrodeposition method in potentiostatic mode was performed at different TeO _2 concentrations of 0.075, 0.150, 0.225, 0.30, and 0.375 mM. The structural, optical, surface morphology, surface roughness, and compositional properties of as-deposited (AD) and annealed (HT) CdTeSe thin film samples were investigated by using x-ray diffraction (XRD), ultraviolet-visible (UV-Vis) spectrophotometry, scanning electron microscopy, scanning probe microscopy and energy-dispersive x-ray spectroscopy, respectively. The XRD results confirmed that CdSe thin films are of hexagonal structure. After TeO _2 was added, the CdTeSe films were found to have mixed hexagonal and cubic phases. The UV-Vis spectrophotometry results confirmed that the absorbance and band gap of the materials varied as the TeO _2 concentration changed. For AD samples, the energy band gap was found to be (1.45–1.75) eV; for HT samples, it varied from (1.53–1.86) eV with TeO _2 concentration. The average surface roughness was 93.17 nm and 79.59 nm for the AD and HT un-doped CdSe films, respectively. The average surface roughness values for the AD TeO _2 doped (CdTeSe) samples were observed to be 23.00, 162.29, and 26.90 nm, and for the HT samples, they were 25.80, 153.10, and 19.35 nm for TeO _2 -concentrations of 0.075,0.150, and 0.375 mM respectively. Compositional analysis verified the presence of Cd, Te, and Se in the films. The results show that CdSeTe thin films have potential applications in thin-film solar cell device technology.

Molecular gas in the central region of the starburst galaxy NGC 253 is complicated because of the combination of different gas kinematics, including stellar feedback, noncircular motions, and magnetic activity. In paper I, we used the latest multitransition, multi-isotope CO-line data sets obtained with the Atacama Large Millimeter/submillimeter Array to classify the molecular gas within the central 850 pc in radius into 28 coherent structures, and we proposed a three-dimensional geometric structure for the gas in the central region of this galaxy. In this paper, we utilize intensity ratios between ^12 CO ( J = 3–2), ^12 CO ( J = 1–0), HCN ( J = 4–3), and SiO ( J = 2–1) to investigate the physical properties of each coherent structure, comparing the distributions with (proto-)star clusters, known as superbubble candidates, and stars. We found that the excitation state of the gas tends to increase toward the galactic center, and we identified high-excitation states in the gas with noncircular motions. From analyses of HCN ( J = 4–3) and SiO ( J = 2–1), we found that the dense, star-forming clumps that drive the starburst reside either at the points connecting any two streams or in the central region where two oppositely directed, accretion flows terminate. Based on analyses of the intensity ratios and the proposed geometric structure, we suggest that some superbubbles may instead be the overlap of the coherent structures rather than an expanding shell. From all these results, we propose a scenario in which the starburst was triggered by cloud–cloud collisions caused by interactions of streams and/or by magnetic flotation and/or efficient accretion along a stellar bar.

Optical tweezers have emerged as a powerful, versatile approach for a range of studies in cellular and molecular biology. A particular highlight has been its use for microrheology measurements in miniscule sample volumes. In this study, we demonstrate the application of optical tweezers to investigate the viscosity of the extracellular matrix surrounding mammalian oocytes and determine whether this is associated with oocyte developmental potential. By analysing the motion of a trapped particle, we can quantify the mechanical properties of this matrix, thus overcoming limitations of traditional passive microrheology techniques that rely on free diffusion. We utilise two maturation methods— in vivo and in vitro —to generate oocytes with differing developmental potential. Our findings indicate that oocytes matured in vivo exhibit higher viability post-fertilisation compared to their in vitro counterparts and we establish a positive correlation between extracellular matrix viscosity and oocyte developmental potential. This work demonstrates that optical tweezers are a novel, non-invasive tool for assessing oocyte quality, contributing to valuable insights to the field of reproductive biology.

The Dark Energy Spectroscopic Instrument (DESI) cosmology survey includes a Bright Galaxy Survey (BGS), which will yield spectra for over 10 million bright galaxies ( r 2, which are either faint quasars with nearby projected companions or very bright quasars with strong absorption features including the Ly α forest, metal absorbers, and/or broad absorption lines.

We present the discovery and characterization of a sub-Saturn exoplanet, TOI-6038 A b, using the PARAS-2 spectrograph. The planet orbits a bright ( m _V = 9.9), metal-rich late F-type star, TOI-6038 A, with T _eff = 6110 ± 100 K, $\mathrm{log}\,g=4.11{8}_{-0.025}^{+0.015}$ , and $[{\rm{Fe/H}}]=0.12{4}_{-0.077}^{+0.079}$ dex. The system also contains a wide-orbit binary companion, TOI-6038 B, an early K-type star at a projected separation of ≈3217 au. We combined radial velocity data from PARAS-2 with photometric data from the Transiting Exoplanet Survey Satellite for joint modeling. TOI-6038 A b has a mass of $78.{5}_{-9.9}^{+9.5}\,{M}_{\oplus }$ and a radius of $6.4{1}_{-0.16}^{+0.20}\,{R}_{\oplus }$ , orbiting in a circular orbit with a period of $5.826731{1}_{-0.0000068}^{+0.0000074}$ days. Internal structure modeling suggests that ≈74% of the planet's mass is composed of dense materials, such as rock and iron, forming a core, while the remaining mass consists of a low-density H/He envelope. TOI-6038 A b lies at the transition regime between the recently identified Neptunian ridge and savanna. Having a density of ${\rho }_{{\rm{P}}}=1.6{2}_{-0.24}^{+0.23}\,{{\rm{g}}\,{\rm{cm}}}^{-3}$ , TOI-6038 A b is compatible with the population of dense ridge planets ( ρ _P ≃ 1.5–2.0 g cm ^−3 ), which have been proposed to have reached their close-in locations through high-eccentricity tidal migration (HEM). First-order estimates suggest that the secular perturbations induced by TOI-6038 B may be insufficient to drive the HEM of TOI-6038 A b. Therefore, it is not clear whether HEM driven by a still undetected companion or early disk-driven migration brought TOI-6038 A b to its present-day close-in orbit. Interestingly, its bright host star makes TOI-6038 A b a prime target for atmospheric escape and orbital architecture observations, which will help us to better understand its overall evolution.

Presently, SOLPS-ITER does not replicate the levels of plasma-molecular interactions seen during deep detachment on the Super-X divertors of MAST-Upgrade and TCV. At low temperatures ( $T_{\mathrm{e}} \lt 1\,\mathrm{eV}$ ) relevant to deep detachment, the AMJUEL reaction database contains discrepancies for detachment relevant molecular processes. In order to correct this the vibrationally resolved ground state Yacora model for H _2 (Yacora $H_{2}(X^{1},v)$ ) has been used to calculate the vibrational distribution and thus from the cross-sections of the Yacora $H_{2}(X^{1},v)$ model effective rate coefficients for these molecular processes. Reduced and extended implementations of Yacora $H_{2}(X^{1},v)$ were constructed to form EIRENE-style databases for use in SOLPS-ITER. The reduced implementation utilises the same processes as EIRENE, but with updated cross-sectional data, whilst the extended implementation adds additional processes. The improved cross-sectional data lowers the threshold for molecular charge exchange (MCX) compared to AMJUEL, whilst the inclusion of the additional processes boosts the vibrational excitation in the molecular ground state providing the additional excitation energy required for MCX to be significant at low temperatures ( $T_{\mathrm{e}} \lt 5\,\mathrm{eV}$ ). When applied to a SOLPS-ITER isolated divertor leg setup, both implementations produce greater levels of MCX that result in elevated molecular ion densities ( $D_{2}^{+}$ ) than the default rate setup. The higher levels of $D_{2}^{+}$ contribute to detachment via increased levels of Molecular Activated Recombination and Molecular Activated Dissociation. These plasma-molecular interactions elevate the neutral population. During detachment this has a strong impact on power and momentum losses, as well as elevated levels of Balmer α line emission and an earlier onset of the ion target flux rollover. These effects are strongest when the extended database is used.

In the pursuit of understanding the multiplicity of massive stars, the OWN Survey has undertaken spectroscopic monitoring of hundreds of targets over the past 20 yr. This effort has led to the discovery of new single-lined spectroscopic binaries. Characterizing the unseen companions of these systems is crucial to deriving precise stellar parameters, including the mass of each component, and constraining formation models for massive binary systems. In this paper, we aim to physically and evolutionarily characterize the stellar components of the massive binary HD 165246. We analyzed spectra obtained by the OWN Survey and used Kepler's second mission (K2) photometry, from which we determined the physical parameters of the system. Thanks to the high-resolution capabilities of the new echelle spectrograph Gemini/GHOST, we could directly detect spectral features of the secondary component for the first time. A very low mass ratio for the system is confirmed ( q ~ 0.16), making this binary one of the few extremely low mass ratio systems known. The primary star has a mass of M _a = 22 ± 1 M _⊙ and a radius of R _a = 7.0 ± 0.1 R _⊙ , while the secondary star has a mass of M _b = 3.4 ± 0.1 M _⊙ and a radius of R _b = 2.22 ± 0.02 R _⊙ . Stellar evolution models indicate that the system has undergone approximately two million years of evolution since its formation. Moreover, the secondary star is identified as a pre-main-sequence object, progressing toward the zero-age main sequence. This paper illustrates the power of high-resolution spectrographs such as GHOST in finding much lower mass, previously unseen stellar components of binary star systems.

We investigate the effect of the spin–orbit (SO) and Rabi couplings on the localization of the spin-1/2 condensate trapped in a one-dimensional random potential. Our studies reveal that the spin-dependent couplings create distinct localization regimes, resulting in various relations between localization and spin-related properties. First, we examine the localization in the linear condensate and find that the SO coupling can lead to a transition of the localized state from the ‘basin-like’ to the ‘void’ region of the potential. For a weak random potential upon an increase in the SO coupling, we find a re-entrant transition from a broad to narrow localized state and back at a higher SO coupling. Further, we analyze the competing role of inter-species and intra-species interactions on the localization of the condensate. We find the appearance of spin-dependent localization as the interactions increase beyond threshold values for a sufficiently strong disorder. Our findings on controlling spin-dependent localization may be useful for future ultracold atomic experiments and corresponding spin-related quantum technologies.

Solar irradiance and its variations in the ultraviolet (UV) control the photochemistry in Earth's atmosphere and influence Earth's climate. The variability in the Mg ii h and k core-to-wing ratio, also known as the Mg ii index, is highly correlated with the solar UV irradiance variability. Because of this, the Mg ii index is routinely used as a proxy for solar UV irradiance variability, which can help to get insights into the influence of solar UV irradiance variability on Earth's climate. Measurements of the Mg ii index, however, have only been carried out since 1978 and do not cover climate-relevant timescales longer than a few decades. Here we present a model to calculate the Mg ii index and its variability based on the well-established Spectral And Total Irradiance REconstruction (SATIRE) model. We demonstrate that our model calculations yield an excellent agreement with the observed Mg ii index variations, both on the solar activity cycle and on the solar rotation timescales. Using this model, we synthesize the Mg ii index time series on climate-relevant timescales of decades and longer. Here we present the time series of the Mg ii index spanning nearly three centuries.

Galaxy interactions can significantly affect the star formation in galaxies, but it remains a challenge to achieve a consensus on the star formation rate (SFR) enhancement in galaxy pairs. Here, we investigate the SFR enhancement of gas-rich galaxy pairs detected by the Widefield ASKAP L -band Legacy All-sky Blind surveY. We construct a sample of 278 paired galaxies spanning a stellar mass ( M _* ) range from 10 ^7.6 to 10 ^11.2 M _⊙ . We obtain individual masses of atomic hydrogen (H i ) for these paired galaxies using a novel deblending algorithm for H i data cubes. Quantifying the interaction stages and strengths with parameters motivated by first-principles analysis, we find that, at fixed stellar and H i mass, the alteration in the SFR of galaxy pairs starts when their dark matter halos are encountered. For galaxies with a stellar mass lower than 10 ^9 M _⊙ , their SFRs show tentative suppression of 1.4 σ after the halo encounter, and then become enhanced when their H i disks overlap, regardless of mass ratios. In contrast, the SFRs of galaxies with M _* > 10 ^9 M _⊙ increase monotonically toward smaller projected distances and radial velocity offsets. When a close companion is present, a pronounced SFR enhancement is found for the most H i -poor high-mass galaxies in our sample. Collecting the observational evidence, we provide a coherent picture of the evolution of galaxy pairs and discuss how the tidal effects and hydrodynamic processes shape the SFR enhancement. Our results provide a coherent picture of gas-rich galaxy interactions and impose constraints on the underlying physical processes.

The HAWC Observatory collected 6 yr of extensive data, providing an ideal platform for long-term monitoring of blazars in the very high energy (VHE) band, without bias toward specific flux states. HAWC continuously monitors blazar activity at TeV energies, focusing on sources with a redshift of z ≤ 0.3, based on the Third Fermi-LAT Catalog of High-Energy sources. We specifically focused our analysis on Mrk 421 and Mrk 501, as they are the brightest blazars observed by the HAWC Observatory. With a data set of 2143 days, this work significantly extends the monitoring previously published, which was based on 511 days of observation. By utilizing HAWC data for the VHE γ -ray emission in the 300 GeV–100 TeV energy range, in conjunction with Swift-XRT data for the 0.3–10 keV X-ray emission, we aim to explore potential correlations between these two bands. For Mrk 501, we found evidence of a long-term correlation. Additionally, we identified a period in the light curve where the flux was very low for more than 2 yr. On the other hand, our analysis of Mrk 421 measured a strong linear correlation for quasi-simultaneous observations collected by HAWC and Swift-XRT. This result is consistent with a linear dependence and a multiple-zone synchrotron self-Compton model to explain the X-ray and γ -ray emission. Finally, as suggested by previous findings, we confirm a harder-when-brighter behavior in the spectral evolution of the flux properties for Mrk 421. These findings contribute to the understanding of blazar emissions and their underlying mechanisms.

We present an observational study of the S284-RE region, a low-metallicity area associated with the extended S284 H ii region. A thermally supercritical filament (mass ∼2402 M _⊙ and length ∼8.5 pc) is investigated using the Herschel column density map. The Spitzer ratio 4.5 μ m/3.6 μ m map traces the H _2 outflows in this filament, where previously reported young stellar objects (YSOs) are spatially distributed. Analysis of the YSO distribution has revealed three active star-forming clusters (YCl1, YCl2, and YCl3) within the filament. YCl3 seems to be the most evolved and YCl2 the youngest, while YCl1 displays signs of nonthermal fragmentation. The JWST (F470N+F444W)/F356W ratio map reveals at least seven bipolar H _2 outflows, with four (olc1–olc4) in YCl1 and three (ol1–ol3) in YCl2. The driving sources of these outflows are identified based on outflow geometry, Atacama Large Millimeter/submillimeter Array (ALMA) continuum peaks, and YSO positions. Two ALMA continuum sources—#2 and #3—from the M – R _eff plot are recognized as potential massive star formation candidates. ALMA continuum source #2 hosts at least three outflow-driving sources, whereas ALMA continuum source #3 contains two. The bipolar outflow olc1, driven by an embedded object within continuum source #2, is likely a massive protostar, as indicated by the Br- α and PAH emissions depicted in the JWST (F405N+F444W)/F356W ratio map. The presence of H _2 knots in the outflows olc1 and ol1 suggests episodic accretion. Overall, the study investigates a massive protostar candidate, driving the ∼2.7 pc H _2 outflow olc1 and undergoing episodic accretion.

We present ∼115 new spectroscopically identified members of the GD-1 tidal stream observed with the 5000-fiber Dark Energy Spectroscopic Instrument (DESI). We confirm the existence of a “cocoon,” which is a broad (FWHM ∼ 2 $\mathop{.}\limits^{\unicode{x000b0}}$ 932 ∼ 460 pc) and kinematically hot (velocity dispersion, σ ∼ 5–8 km s ^−1 ) component that surrounds a narrower (FWHM ∼ 0 $\mathop{.}\limits^{\unicode{x000b0}}$ 353 ∼ 55 pc) and colder [( σ = 3.09 ± 0.76 km s ^−1 )] thin stream component (based on a median per star velocity precision of 2.7 km s ^−1 ). The cocoon extends over at least a 30 ^∘ segment of the stream observed by DESI. The thin and cocoon components have similar mean values of [Fe/H]: −2.54 ± 0.04 dex and −2.47 ± 0.06 dex, suggestive of a common origin. The data are consistent with the following scenarios for the origin of the cocoon. The progenitor of the GD-1 stream was an accreted globular cluster (GC) and: (a) the cocoon was produced by pre-accretion tidal stripping of the GC while it was still inside its parent dwarf galaxy; (b) the cocoon comprises debris from the parent dwarf galaxy; (c) an initially thin GC tidal stream was heated by impacts from dark subhalos in the Milky Way; (d) an initially thin GC stream was heated by a massive Sagittarius dwarf galaxy; or a combination of some of these. Future DESI spectroscopy and detailed modeling may enable us to distinguish between these possible origins.

Fast X-ray transients (FXTs) are a new observational class of phenomena with no clear physical origin. This is at least partially a consequence of limited multiwavelength follow-up of this class of transients in real time. Here we present deep optical ( g - and i -band) photometry with Keck, and prompt radio observations with the Very Large Array of FXT 210423 obtained at δ t ≈ 14–36 days since the X-ray trigger. We use these multiband observations, combined with publicly available data sets, to constrain the presence and physical properties of on-axis and off-axis relativistic jets such as those that can be launched by neutron star mergers and tidal disruption events, which are among the proposed theoretical scenarios of FXTs. Considering a wide range of possible redshifts z ≤ 3.5, circumstellar medium density n = 10 ^−6 –10 ^−1 cm ^−3 , and isotropic-equivalent jet kinetic energy E _k _,iso = 10 ^48 –10 ^55 erg, we find that we can rule out wide jets with opening angle θ _j = 15° viewed within 10° off-axis. For more collimated jets ( θ _j = 3°) we can only rule out on-axis ( θ _obs = 0°) orientations. This study highlights the constraining power of prompt multiwavelength observations of FXTs discovered in real time by current (e.g., Einstein Probe) and future facilities.

On 2022 September 26, the Double Asteroid Redirection Test (DART) spacecraft intentionally collided with Dimorphos, the moon of the binary asteroid system 65803 Didymos. This collision provided the first full-scale test of a kinetic impactor for planetary defense. Images from DART’s DRACO camera revealed Dimorphos to be an oblate spheroid covered in boulders of varying sizes and shapes. Very little was known about Dimorphos prior to DART’s impact, including its shape, structure, and material properties. Approach observations and those following the DART impact have provided crucial knowledge that narrows the parameter space relevant to modeling the impact into Dimorphos. Here we present the results of a suite of hydrocode simulations of the DART impact on Dimorphos. Despite remaining uncertainties, initial models of DART’s kinetic impact provide important information about the results of DART (e.g., potential crater size and morphology, ejecta mass) and the properties of Dimorphos. Simulations here suggest that Dimorphos has near-surface strength ranging from a few Pascals to tens of kPa, which corresponds to crater sizes of ∼40–60 m. Simulated crater sizes provide a crucial comparison metric for the European Space Agency Hera mission when it arrives at the Didymos system. Hera’s measurement of crater size in combination with measurement of Dimorphos’s mass will allow us to assess our simulations and provide the information needed to make the DART impact experiment both the first test of a planetary defense mitigation mission and the first full-scale planetary defense simulation validation exercise.

Producing optimized and accurate transmission spectra of exoplanets from telescope data has traditionally been a manual and labor intensive procedure. Here we present the results of the first attempt to improve and standardize this procedure by using artificial-intelligence-based (AI-based) processing of light curves and spectroscopic data from transiting exoplanets observed with the Hubble Space Telescope's (HST) Wide Field Camera (WFC3) instrument. We implement an AI-based parameter optimizer that autonomously operates the Eureka! pipeline to produce homogeneous transmission spectra of publicly available HST WFC3 datasets, spanning exoplanet types from hot Jupiters to sub-Neptunes. Surveying 42 exoplanets with temperatures between 280 and 2580 K, we confirm modeled relationships between the amplitude of the water band at 1.4 μ m of hot Jupiters and their equilibrium temperatures. We also identify a similar, novel trend in Neptune/sub-Neptune atmospheres, but shifted to cooler temperatures. Excitingly, a planet-mass versus equilibrium-temperature diagram reveals a “Clear Sky Corridor,” where planets between 700 and 1700 K (depending on the mass) show stronger 1.4 μ m H _2 O band measurements. This novel trend points to metallicity as a potentially important driver of aerosol formation. With HST sculpting this foundational understanding for aerosol formation in various exoplanet types ranging from Jupiters to sub-Neptunes, we present a compelling platform for the James Webb Space Telescope to discover similar atmospheric trends for more planets across a broader wavelength range.

The molecular Kennicutt–Schmidt Law has been key for understanding star formation (SF) in galaxies across all redshifts. However, recent subkiloparsec observations of nearby galaxies reveal deviations from the nearly unity slope ( N ) obtained with disk-averaged measurements. We study SF and molecular gas (MG) distribution in the early-stage luminous infrared galaxy merger Arp 240 (NGC 5257-8). Using Very Large Array radio continuum (RC) and Atacama Large Millimeter/submillimeter Array CO(2–1) observations at 500 pc scale, with a uniform grid analysis, we estimate SF rates and MG surface densities (Σ _SFR and ${{\rm{\Sigma }}}_{{{\rm{H}}}_{2}}$ , respectively). In Arp 240, N is sublinear at 0.52 ± 0.17. For NGC 5257 and NGC 5258, N is 0.52 ± 0.16 and 0.75 ± 0.15, respectively. We identify two SF regimes: high surface brightness (HSB) regions in RC with N ~ 1, and low surface brightness (LSB) regions with shallow N (ranging 0.15 ± 0.09–0.48 ± 0.04). Median CO(2–1) linewidth and MG turbulent pressure ( P _turb ) are 25 km s ^−1 and 9 × 10 ^5 K cm ^−3 . No significant correlation was found between Σ _SFR and CO(2–1) linewidth. However, Σ _SFR correlates with P _turb , particularly in HSB regions ( ρ > 0.60). In contrast, SF efficiency moderately anticorrelates with P _turb in LSB regions but shows no correlation in HSB regions. Additionally, we identify regions where peaks in SF and MG are decoupled, yielding a shallow N (≤0.28 ± 0.18). Overall, the range of N reflects distinct physical properties and distribution of both the SF and MG, which can be masked by disk-averaged measurements.

A multiwavelength, multiscale study of the Mon R2 hub–filament system (HFS) reveals a spiral structure, with the central hub containing more mass than its filaments. C ^18 O(1–0) emission detected by the Atacama Large Millimeter/submillimeter Array (ALMA) reveals several accreting filaments connected to a molecular ring (size ∼0.18 pc × 0.26 pc). The molecular ring surrounds the infrared (IR) ring (size ~0.12 pc × 0.16 pc), which is not usually observed. The IR ring encircles IR-quiet regions and a population of embedded near-IR sources, including the massive stars IRS 1 and IRS 2. ALMA HNC(3–2) line data reveal a mirrored B-shaped feature (extent ∼19,000 au × 39,000 au) toward the eastern part of the molecular ring, suggesting expansion at ~2.25 km s ^−1 . Distinct HNC substructures in both redshifted and blueshifted velocity components are investigated toward the B-shaped feature. The presence of these braid-like substructures in each velocity component strongly suggests instability in photon-dominated regions. A dusty shell-like feature (extent ~0.04 pc × 0.07 pc; mass ~7 M _⊙ ) hosting IRS 1 is identified in the ALMA 1.14 mm continuum map, centered toward the base of the B-shaped feature. The IR and dense molecular rings are likely shaped by feedback from massive stars, driven by high pressures of between 10 ^−8 and 10 ^−10 dyn cm ^−2 , observed within a 1 pc range of the B0 zero-age main-sequence star powering the ultracompact H ii region. Overall, these outcomes support the idea that the Mon R2 HFS transitioned from IR-quiet to IR-bright, driven by the interaction between gas accretion and feedback from massive stars.

Identifying Galactic PeVatrons (PeV particle accelerators) from ultrahigh-energy (UHE, >100 TeV) γ -ray sources plays a crucial role in revealing the origin of Galactic cosmic rays. The UHE source 1LHAASO J1857+0203u is suggested to be associated with HESS J1858+020, which may be attributed to the possible PeVatron candidate supernova remnant (SNR) G35.6−0.4 or H ii region G35.6−0.5. We perform detailed analysis on the very-high-energy and UHE γ -ray emissions toward this region with data from the Large High Altitude Air Shower Observatory (LHAASO). 1LHAASO J1857+0203u is detected with a significance of 11.6 σ above 100 TeV, indicating the presence of a PeVatron. It has an extent of ∼0 $\mathop{.}\limits^{\unicode{x000B0}}$ 18 with a power-law (PL) spectral index of ∼2.5 at 1–25 TeV and pointlike emission with a PL spectral index of ∼3.2 above 25 TeV. Using archival CO and H i data, we identify some molecular and atomic clouds that may be associated with the TeV γ -ray emissions. Our modeling indicates that the TeV γ -ray emissions are unlikely to arise from clouds illuminated by the protons that escaped from SNR G35.6−0.4. In the scenario in which H ii region G35.6−0.5 could accelerate particles to the UHE band, the observed GeV–TeV γ -ray emission could be well explained by a hadronic model with a PL spectral index of ∼2.0 and cutoff energy of ∼450 TeV. However, an origin in an evolved pulsar wind nebula cannot be ruled out.

We present the discovery of TOI-7041 b (TIC 201175570 b), a hot Saturn transiting a red giant star with measurable stellar oscillations. We observe solar-like oscillations in TOI-7041 with a frequency of maximum power of ${\nu }_{{\rm{\max }}}\,=\,$ 218.50 ± 2.23 μ Hz and a large frequency separation of Δ ν = 16.5282 ± 0.0186 μ Hz. Our asteroseismic analysis indicates that TOI-7041 has a mass of 1.07 ± 0.05(stat) ± 0.02(sys) M _⊙ and a radius of 4.10 ± 0.06(stat) ± 0.05(sys) R _⊙ , making it one of the largest stars around which a transiting planet has been discovered with the Transiting Exoplanet Survey Satellite (TESS), and the mission's first oscillating red giant with a transiting planet. TOI-7041 b has an orbital period of 9.691 ± 0.006 days and a low eccentricity of e = 0.04 ± 0.04. We measure a planet radius of 1.02 ± 0.03 R _Jup with TESS photometry, and a planet mass of 0.36 ± 0.16 M _Jup (114 ± 51 M _⊕ ) with ground-based radial velocity measurements. TOI-7041 b appears less inflated than similar systems receiving equivalent incident flux, and its circular orbit indicates that it is not undergoing tidal heating due to circularization. The asteroseismic analysis of the host star provides some of the tightest constraints on the stellar properties of a TESS planet host and enables precise characterization of the hot Saturn. This system joins a small number of TESS-discovered exoplanets orbiting stars that exhibit clear stellar oscillations and indicates that extended TESS observations of evolved stars will similarly provide a path to improved exoplanet characterization.

In this study, we have investigated the structural, electronic, optical, and magnetic properties of LiFePO _4 (LFP), which is a prominent cathode material for lithium-ion batteries (LIBs). In order to analyse the properties of LFP, we have carried out the calculations using Density Functional Theory (DFT) combined with the Hubbard (U) correction (i.e., DFT + U), as implemented in the quantum-espresso (QE) code. We performed the structural optimization and found that LFP has a stable olivine structure with equilibrium parameters of a = 4.64 Å, b = 5.98 Å, and c = 10.34 Å. It is shown that LFP has a direct band gap value of 3.82 eV, which is very close to experiment values of 3.6-4.0 eV. The projected density of states (PDOS) of the LFP closely matches with experimental reports of the electronic structure of the material, where the Fe 3 d states form tight bands above the O 2 p band. The analysis of optical properties shows a significant absorption property in the visible spectrum, reflecting its additional potential for photoactive application. We have also examined the magnetic properties, which reveal that LFP exhibits antiferromagnetic ordering, which plays a critical role in the stability of the material during lithium cycling. The investigated properties of LFP in this work, thus, highlight its viability as an effective cathode material for the next-generation battery technologies with a multifaced applications.

Using data from the first flight of Spider and from the Planck High Frequency Instrument, we probe the properties of polarized emission from interstellar dust in the Spider observing region. Component-separation algorithms operating in both the spatial and harmonic domains are applied to probe their consistency and to quantify modeling errors associated with their assumptions. Analyses of diffuse Galactic dust emission spanning the full Spider region demonstrate (i) a spectral energy distribution that is broadly consistent with a modified-blackbody (MBB) model with a spectral index of β _d = 1.45 ± 0.05 (1.47 ± 0.06) for E ( B )-mode polarization, slightly lower than that reported by Planck for the full sky; (ii) an angular power spectrum broadly consistent with a power law; and (iii) no significant detection of line-of-sight polarization decorrelation. Tests of several modeling uncertainties find only a modest impact (∼10% in σ _r ) on Spider ’s sensitivity to the cosmological tensor-to-scalar ratio. The size of the Spider region further allows for a statistically meaningful analysis of the variation in foreground properties within it. Assuming a fixed dust temperature T _d = 19.6 K, an analysis of two independent subregions of that field results in inferred values of β _d = 1.52 ± 0.06 and β _d = 1.09 ± 0.09, which are inconsistent at the 3.9 σ level. Furthermore, a joint analysis of Spider and Planck 217 and 353 GHz data within one subregion is inconsistent with a simple MBB at more than 3 σ , assuming a common morphology of polarized dust emission over the full range of frequencies. This evidence of variation may inform the component-separation approaches of future cosmic microwave background polarization experiments.

Morphological features in galaxies—like spiral arms, bars, rings, and tidal tails, etc.—carry information about their structure, origin, and evolution. It is therefore important to catalog and study such features and to correlate them with other basic galaxy properties, the environments in which the galaxies are located, and their interactions with other galaxies. The volume of present and future data on galaxies is so large that traditional methods, which involve expert astronomers identifying morphological features through visual inspection, are no longer sufficient. It is therefore necessary to use AI-based techniques like machine learning and deep learning to find morphological structures quickly and efficiently. We report in this study the application of deep learning for finding ring-like structures in galaxy images from the Sloan Digital Sky Survey (SDSS) DR18. We use a catalog by R. J. Buta of ringed galaxies from SDSS to train the network, reaching good accuracy and recall, and generate a catalog of 29,420 galaxies, of which 4855 have ring-like structures with prediction confidence exceeding 90%. Using a catalog of barred galaxy images identified by S. Abraham et. al. with deep-learning techniques, we identify a set of 2087 galaxies with bars as well as rings. The catalog should be very useful in understanding the origin of these important morphological structures. As an example of the usefulness of the catalog, we explore the environments and star formation characteristics of the ring galaxies in our sample.

The structure and chemistry of the dusty interstellar medium (ISM) are shaped by complex processes that depend on the local radiation field, gas composition, and dust grain properties. Of particular importance are polycyclic aromatic hydrocarbons (PAHs), which emit strong vibrational bands in the mid-infrared, and play a key role in the ISM energy balance. We recently identified global correlations between PAH band and optical line ratios across three nearby galaxies, suggesting a connection between PAH heating and gas ionization throughout the ISM. In this work, we perform a census of the PAH heating–gas ionization connection using ∼700,000 independent pixels that probe scales of 40–150 pc in 19 nearby star-forming galaxies from the PHANGS survey. We find a universal relation between $\mathrm{log}$ PAH(11.3 μ m/7.7 μ m) and $\mathrm{log}$ ([S ii ]/H α ) with a slope of ∼0.2 and a scatter of ∼0.025 dex. The only exception is a group of anomalous pixels that show unusually high (11.3 μ m/7.7 μ m) PAH ratios in regions with old stellar populations and high starlight-to-dust emission ratios. Their mid-infrared spectra resemble those of elliptical galaxies. Active galactic nucleus hosts show modestly steeper slopes, with a ∼​​​​​​10% increase in PAH(11.3 μ m/7.7 μ m) in the diffuse gas on kiloparsec scales. This universal relation implies an emerging simplicity in the complex ISM, with a sequence that is driven by a single varying property: the spectral shape of the interstellar radiation field. This suggests that other properties, such as gas-phase abundances, gas ionization parameter, and grain charge distribution, are relatively uniform in all but specific cases.

Hub-filament systems (HFSs) are potential sites of massive star formation (MSF). To understand the role of filaments in MSF and the origin of HFSs, we conducted a multiscale and multiwavelength observational investigation of the molecular cloud G321.93–0.01. The ^13 CO( J = 2–1) data reveal multiple HFSs, namely, HFS-1, HFS-2, and a candidate HFS (C-HFS). HFS-1 and HFS-2 exhibit significant mass accretion rates ( ${\dot{M}}_{| | }$ > 10 ^−3 M _⊙ yr ^−1 ) to their hubs (i.e., Hub-1 and Hub-2, respectively). Hub-1 is comparatively massive, having higher ${\dot{M}}_{| | }$ than Hub-2, allowing to derive a relationship ${\dot{M}}_{| | }\propto {M}_{{\rm{hub}}}^{\beta }$ , with β ~ 1.28. Detection of three compact H ii regions within Hub-1 using MeerKAT 1.28 GHz radio continuum data and the presence of a clump (ATL-3), which meets Kauffmann and Pillai's criteria for MSF, confirm the massive star-forming activity in HFS-1. We find several low-mass Atacama Large Millimeter/submillimeter Array cores (1–9 M _⊙ ) inside ATL-3. The presence of a compact H ii region at the hub of C-HFS confirms that it is active in MSF. Therefore, HFS-1 and C-HFS are in relatively evolved stages of MSF, where massive stars have begun ionizing their surroundings. Conversely, despite a high ${\dot{M}}_{| | }$ , the nondetection of radio continuum emission toward Hub-2 suggests it is in the relatively early stages of MSF. Analysis of ^13 CO( J = 2–1) data reveals that the formation of HFS-1 was likely triggered by the collision of a filamentary cloud about 1 Myr ago. In contrast, the relative velocities (≳1 km s ^−1 ) among the filaments of HFS-2 and C-HFS indicate their formation through the merging of filaments.

We present JWST NIRCam imaging targeting 13 z ~ 3 infrared-luminous ( L _IR ∼ 5 × 10 ^12 L _⊙ ) galaxies from the ALESS survey with uniquely deep, high-resolution (0 $\mathop{.}\limits^{\unicode{x02033}}$ 08–0 $\mathop{.}\limits^{^{\prime\prime} }$ 16) Atacama Large Millimeter/submillimeter Array 870 μ m imaging. The 2.0–4.4 μ m (observed frame) NIRCam imaging reveals the rest-frame near-infrared stellar emission in these submillimeter-selected galaxies at the same (sub)kiloparsec resolution as the 870 μ m dust continuum. The newly revealed stellar morphologies show striking similarities with the dust continuum morphologies at 870 μ m, with the centers and position angles agreeing for most sources, clearly illustrating that the spatial offsets reported previously between the 870 μ m and Hubble Space Telescope morphologies were due to strong differential dust obscuration. The F444W sizes are 78% ± 21% larger than those measured at 870 μ m, in contrast to recent results from hydrodynamical simulations that predict larger 870 μ m sizes. We report evidence for significant dust obscuration in F444W for the highest-redshift sources, emphasizing the importance of longer-wavelength MIRI imaging. The majority of the sources show evidence that they are undergoing mergers/interactions, including tidal tails/plumes—some of which are also detected at 870 μ m. We find a clear correlation between NIRCam colors and 870 μ m surface brightness on ∼1 kpc scales, indicating that the galaxies are primarily red due to dust—not stellar age—and we show that the dust structure on ∼kpc scales is broadly similar to that in nearby galaxies. Finally, we find no strong stellar bars in the rest-frame near-infrared, suggesting the extended bar-like features seen at 870 μ m are highly obscured and/or gas-dominated structures that are likely early precursors to significant bulge growth.

Recent ground- and space-based surveys have shown that planets between Earth and Neptune in size, known as “super-Earths,” are among the most frequently found planets in the Galaxy. Although the JWST era has provided high-quality atmospheric data on many such super-Earths, modeling tools are crucial for understanding their unobservable interiors. Consequently, interior studies represent the next essential step in gaining a comprehensive understanding of this class of exoplanets. This study investigates the interior structure, thermal evolution, and atmospheric dynamics of the super-Earth GJ 486b using SERPINT , a 1D self-consistent coupled interior structure and evolution model, aiming to understand the planet’s thermal evolution based on an Earth-like structure. Our results indicate that GJ 486b’s core is approximately 1.34 times larger than Earth’s, with a core pressure of about 1171 GPa. The thermal evolution model predicts that the planet’s mantle cools and solidifies over approximately 0.93 Myr. As the magma ocean cools, water is released from the melt, forming a water-rich atmosphere during early solidification. Photolysis of water vapor and subsequent hydrogen escape lead to oxygen accumulation, forming a water- and oxygen-rich secondary atmosphere. Future high-sensitivity JWST observations, with improved wavelength coverage and the detection of additional trace gases, will enable a detailed analysis of the planet’s atmospheric composition, providing crucial insights into the interior, surface, and subsurface properties of GJ 486b.

A transiting planet was recently discovered around a star in the Taurus star-forming region, IRAS 04125+2902, making it one of the youngest known planets. The discovery paper cited two age estimates for IRAS 04125+2902, one based on a comparison to two sets of model isochrones in the Hertzsprung–Russell diagram and a second age reported by an earlier study for a putative population in Taurus that includes IRAS 04125+2902 (D4-North). However, the model isochrones in question differ significantly for most temperatures and luminosities of young low-mass stars, and do not reproduce the observed sequences for the TW Hya and 32 Ori associations (10 and 21 Myr). Meanwhile, as found in my previous work, D4-North is a collection of field stars and fragments of several distinct Taurus groups and older associations, so its quoted age is not meaningful. The true parent population for IRAS 04125+2902 is a small group that is ∼35 pc behind the L1495 and B209 clouds (B209N). I have analyzed the age of B209N through a comparison to TW Hya and 32 Ori. The M-star sequences in the latter two associations have the same shapes, but the sequence for B209N is flatter, indicating that >M4 stars at ages of