Search

Precise direct cosmic-ray (CR) measurements provide an important probe to study the energetic particle sources in our Galaxy, and the interstellar environment through which these particles propagate. Uncertainties on hadronic models, ion-nucleon cross sections in particular, are currently the limiting factor towards obtaining more accurate CR ion flux measurements with calorimetric space-based experiments. We present an energy-dependent measurement of the inelastic cross section of protons and helium-4 nuclei (alpha particles) on a Bi$_4$Ge$_3$O$_{12}$ target, using 88 months of data collected by the DAMPE space mission. The kinetic energy range per nucleon of the measurement points ranges from 18 GeV to 9 TeV for protons, and from 5 GeV/n to 3 TeV/n for helium-4 nuclei. Our results lead to a significant improvement of the CR flux normalisation. In the case of helium-4, these results correspond to the first cross section measurements on a heavy target material at energies above 10 GeV/n., Comment: 17 pages, submitted to PRD

The GLOSTAR survey studies star formation with the VLA and the Effelsberg 100m telescope in the Galactic plane (-2d

We present results on simultaneous observations of Class~I methanol masers at 25, 36, and 44 GHz towards 22 Galactic targets carried out with the Effelsberg 100-m telescope. The study investigates relations between the hyperfine (HF) structure of the torsion-rotation transitions in CH3OH and maser activity. By analyzing the radial velocity shifts between different maser lines together with the patterns of the HF structure based on laboratory measurements and quantum-chemical calculations, we find that in any source only one specific HF transition forms the maser emission and that this transition changes from source to source. The physical conditions leading to this selective behavior are still unclear. Using accurate laboratory rest frequencies for the 25 GHz transitions, we have refined the centre frequencies for the HF multiplets at 36, 44, and 95 GHz: f_36 = (36169.2488 +/- 0.0002_stat +/- 0.0004_sys) MHz. f_44 = (44069.4176 +/- 0.0002_stat +/- 0.0004_sys) MHz, and f_95 = (95169.4414 +/- 0.0003_stat +/- 0.0004_sys) MHz. Comparison with previous observations of 44 GHz masers performed 6-10 years ago with a Korean 21-m KVN telescope towards the same targets confirms the kinematic stability of Class~I maser line profiles during this time interval and reveals a systematic radial velocity shift of 0.013 +/- 0.005 km/s between the two telescopes., Comment: 24 pages, 8 figures, 9 tables; accepted for publication in MNRAS

Studies of Galactic HII regions are of crucial importance for studying star formation and the evolution of the interstellar medium. Gaining an insight into their physical characteristics contributes to a more comprehensive understanding of these phenomena. The GLOSTAR project aims to provide a GLObal view on STAR formation in the Milky Way by performing an unbiased and sensitive survey. This is achieved by using the extremely wideband (4{-}8 GHz) C-band receiver of the Karl G. Jansky Very Large Array and the Effelsberg 100 m telescope. Using radio recombination lines observed in the GLOSTAR survey with the VLA in D-configuration with a typical line sensitivity of 1{\sigma} {\sim} 3.0 mJy beam{^-1} at {\sim} 5 km s{^-1} and an angular resolution of 25", we cataloged 244 individual Galactic HII regions and derived their physical properties. We examined the mid-infrared (MIR) morphology of these HII regions and find that a significant portion of them exhibit a bubble-like morphology in the GLIMPSE 8 {\mu}m emission. We also searched for associations with the dust continuum and sources of methanol maser emission, other tracers of young stellar objects, and find that 48\% and 14\% of our HII regions, respectively, are coextensive with those. We measured the electron temperature for a large sample of HII regions within Galactocentric distances spanning from 1.6 to 13.1 kpc and derived the Galactic electron temperature gradient as {\sim} 372 {\pm} 28 K kpc{^-1} with an intercept of 4248 {\pm} 161 K, which is consistent with previous studies., Comment: Accepted for publication in A&A

The kinetic temperature structure of the massive filament DR21 has been mapped using the IRAM 30 m telescope. This mapping employed the para-H$_2$CO triplet ($J_{\rm K_aK_c}$ = 3$_{03}$--2$_{02}$, 3$_{22}$--2$_{21}$, and 3$_{21}$--2$_{20}$) on a scale of $\sim$0.1 pc. By modeling the averaged line ratios of para-H$_{2}$CO with RADEX under non-LTE assumptions, the kinetic temperature of the dense gas was derived at a density of $n$(H$_{2}$) = 10$^{5}$ cm$^{-3}$. The para-H$_2$CO lines reveal significantly higher temperatures than NH$_3$ (1,1)/(2,2) and FIR wavelengths. The dense clumps appear to correlate with the notable kinetic temperature. Among the four dense cores (N44, N46, N48, and N54), temperature gradients are observed on a scale of $\sim$0.1-0.3 pc. This suggests that the warm dense gas is influenced by internal star formation activity. With the exception of N54, the temperature profiles of these cores were fitted with power-law indices ranging from $-$0.3 to $-$0.5. This indicates that the warm dense gas is heated by radiation emitted from internally embedded protostar(s) and/or clusters. While there is no direct evidence supporting the idea that the dense gas is heated by shocks resulting from a past explosive event in the DR21 region, our measurements toward the DR21W1 region provide compelling evidence that the dense gas is indeed heated by shocks originating from the western DR21 flow. Higher temperatures appear to be associated with turbulence. The physical parameters of the dense gas in the DR21 filament exhibit a remarkable similarity to the results obtained in OMC-1 and N113. This may imply that the physical mechanisms governing the dynamics and thermodynamics of dense gas traced by H$_{2}$CO in diverse star formation regions may be dominated by common underlying principles despite variations in specific environmental conditions. (abbreviated), Comment: 16 pages, 8 figures, 3 tabels. Accepted for publication by Astronomy & Astrophysics

Recently, a surge of 3D style transfer methods has been proposed that leverage the scene reconstruction power of a pre-trained neural radiance field (NeRF). To successfully stylize a scene this way, one must first reconstruct a photo-realistic radiance field from collected images of the scene. However, when only sparse input views are available, pre-trained few-shot NeRFs often suffer from high-frequency artifacts, which are generated as a by-product of high-frequency details for improving reconstruction quality. Is it possible to generate more faithful stylized scenes from sparse inputs by directly optimizing encoding-based scene representation with target style? In this paper, we consider the stylization of sparse-view scenes in terms of disentangling content semantics and style textures. We propose a coarse-to-fine sparse-view scene stylization framework, where a novel hierarchical encoding-based neural representation is designed to generate high-quality stylized scenes directly from implicit scene representations. We also propose a new optimization strategy with content strength annealing to achieve realistic stylization and better content preservation. Extensive experiments demonstrate that our method can achieve high-quality stylization of sparse-view scenes and outperforms fine-tuning-based baselines in terms of stylization quality and efficiency.

We report the observation of a coalescing compact binary with component masses $2.5\text{-}4.5~M_\odot$ and $1.2\text{-}2.0~M_\odot$ (all measurements quoted at the 90% credible level). The gravitational-wave signal GW230529_181500 was observed during the fourth observing run of the LIGO-Virgo-KAGRA detector network on 2023 May 29 by the LIGO Livingston Observatory. The primary component of the source has a mass less than $5~M_\odot$ at 99% credibility. We cannot definitively determine from gravitational-wave data alone whether either component of the source is a neutron star or a black hole. However, given existing estimates of the maximum neutron star mass, we find the most probable interpretation of the source to be the coalescence of a neutron star with a black hole that has a mass between the most massive neutron stars and the least massive black holes observed in the Galaxy. We provisionally estimate a merger rate density of $55^{+127}_{-47}~\text{Gpc}^{-3}\,\text{yr}^{-1}$ for compact binary coalescences with properties similar to the source of GW230529_181500; assuming that the source is a neutron star-black hole merger, GW230529_181500-like sources constitute about 60% of the total merger rate inferred for neutron star-black hole coalescences. The discovery of this system implies an increase in the expected rate of neutron star-black hole mergers with electromagnetic counterparts and provides further evidence for compact objects existing within the purported lower mass gap., Comment: 45 pages (10 pages author list, 13 pages main text, 1 page acknowledgements, 13 pages appendices, 8 pages bibliography), 17 figures, 16 tables. Update to match version published in The Astrophysical Journal Letters. Data products available from https://zenodo.org/records/10845779

We present the results of a search for ammonia maser emission in 119 Galactic high-mass star-forming regions (HMSFRs) known to host 22 GHz H$_2$O maser emission. Our survey has led to the discovery of non-metastable NH$_3$ inversion line masers toward 14 of these sources. This doubles the number of known non-metastable ammonia masers in our Galaxy, including nine new very high excitation ($J,K$)~=~(9,6) maser sources. These maser lines, including NH$_3$ (5,4), (6,4), (6,5), (7,6), (8,6), (9,6), (9,8), (10,8), and (11,9), arise from energy levels of 342 K, 513 K, 465 K, 606 K, 834 K, 1090 K, 942 K, 1226 K, and 1449 K above the ground state. Additionally, we tentatively report a new metastable NH$_3$ (3,3) maser in G048.49 and an NH$_3$ (7,7) maser in G029.95. Our observations reveal that all of the newly detected NH$_3$ maser lines exhibit either blueshifted or redshifted velocities with respect to the source systemic velocities. Among the non-metastable ammonia maser lines, larger velocity distributions, offset from the source systemic velocities, are found in the ortho-NH$_3$ ($K=3n$) than in the para-NH$_3$ ($K\neq3n$) transitions., Comment: 14 pages, 4 tables, 9 figures. Accepted for publication in A&A

Neural radiance fields (NeRFs) have achieved impressive view synthesis results by learning an implicit volumetric representation from multi-view images. To project the implicit representation into an image, NeRF employs volume rendering that approximates the continuous integrals of rays as an accumulation of the colors and densities of the sampled points. Although this approximation enables efficient rendering, it ignores the direction information in point intervals, resulting in ambiguous features and limited reconstruction quality. In this paper, we propose an anisotropic neural representation learning method that utilizes learnable view-dependent features to improve scene representation and reconstruction. We model the volumetric function as spherical harmonic (SH)-guided anisotropic features, parameterized by multilayer perceptrons, facilitating ambiguity elimination while preserving the rendering efficiency. To achieve robust scene reconstruction without anisotropy overfitting, we regularize the energy of the anisotropic features during training. Our method is flexiable and can be plugged into NeRF-based frameworks. Extensive experiments show that the proposed representation can boost the rendering quality of various NeRFs and achieve state-of-the-art rendering performance on both synthetic and real-world scenes.

As part of the GLOSTAR (GLObal view of STAR formation in the Milky Way) survey, we present the high-resolution continuum source catalog for the regions (l = 2-28, 36-40, 56-60, &|b|<1.0), observed with the Karl G. Jansky Very Large Array (VLA) in its B-configuration. The continuum images are optimized to detect compact sources on angular scales up to 4", and have a typical noise level of 1sigma ~ 0.08mJy/beam for an angular resolution of 1", which makes GLOSTAR currently the highest resolution as well as the most sensitive radio survey of the northern Galactic plane at 4-8GHz. We extracted 13354 sources above a threshold of 5sigma and 5437 sources above 7sigma that represent the high-reliability catalog. We determined the in-band spectral index (alpha) for the sources in the 7sigma-threshold catalog. The mean value is alpha=-0.6, which indicates that the catalog is dominated by sources emitting non-thermal radio emission. We identified the most common source types detected in radio surveys: 251 HII region candidates (113 new), 282 planetary nebulae (PNe) candidates (127 new), 784 radio star candidates (581 new), and 4080 extragalactic radio source candidates (2175 new). A significant fraction of HII regions and PNe candidates have alpha<-0.1 indicating that these candidates could contain radio jets, winds or outflows from high-mass and low-mass stellar objects. We identified 245 variable radio sources by comparing the flux densities of compact sources from the GLOSTAR survey and the Co-Ordinated Radio `N' Infrared Survey for High-mass star formation (CORNISH), and find that most of them are infrared quiet. The catalog is typically 95% complete for point sources at a flux density of 0.6 mJy (i.e. typical 7sigma level) and the systematic positional uncertainty is <= 0.1". The GLOSTAR data and catalogs are available online at https://glostar.mpifr-bonn.mpg.de., Comment: 25pages, 21 figures, has been accepted for publication in Astronomy & Astrophysics (A&A)

Sulfur isotope ratios have emerged as a promising tool for tracing stellar nucleosynthesis, quantifying stellar populations, and investigating the chemical evolution of galaxies. While extensively studied in the Milky Way, in extragalactic environments they remain largely unexplored. We focus on investigating the sulfur isotope ratios in the Large Magellanic Cloud (LMC) to gain insights into sulfur enrichment in this nearby system and to establish benchmarks for such ratios in metal-poor galaxies. We conducted pointed observations of CS and its isotopologues toward N113, one of the most prominent star-formation regions in the LMC, utilizing the Atacama Pathfinder EXperiment 12~m telescope. We present the first robust detection of C$^{33}$S in the LMC by successfully identifying two C$^{33}$S transitions on a large scale of $\sim$5 pc. Our measurements result in an accurate determination of the $^{34}$S/$^{33}$S isotope ratio, which is 2.0$\pm$0.2. Our comparative analysis indicates that the $^{32}$S/$^{33}$S and $^{34}$S/$^{33}$S isotope ratios are about a factor of 2 lower in the LMC than in the Milky Way. Our findings suggest that the low $^{34}$S/$^{33}$S isotope ratio in the LMC can be attributed to a combination of the age effect, low metallicity, and star formation history., Comment: 6 pages, 1 figures, 2 tables, accepted for publication in A&A, adjusted to the final version

Participant selection (PS) helps to accelerate federated learning (FL) convergence, which is essential for the practical deployment of FL over mobile devices. While most existing PS approaches focus on improving training accuracy and efficiency rather than residual energy of mobile devices, which fundamentally determines whether the selected devices can participate. Meanwhile, the impacts of mobile devices' heterogeneous wireless transmission rates on PS and FL training efficiency are largely ignored. Moreover, PS causes the staleness issue. Prior research exploits isolated functions to force long-neglected devices to participate, which is decoupled from original PS designs. In this paper, we propose a residual energy and wireless aware PS design for efficient FL training over mobile devices (REWAFL). REW AFL introduces a novel PS utility function that jointly considers global FL training utilities and local energy utility, which integrates energy consumption and residual battery energy of candidate mobile devices. Under the proposed PS utility function framework, REW AFL further presents a residual energy and wireless aware local computing policy. Besides, REWAFL buries the staleness solution into its utility function and local computing policy. The experimental results show that REW AFL is effective in improving training accuracy and efficiency, while avoiding "flat battery" of mobile devices.

Protonated hydrogen cyanide, HCNH$^{+}$, plays a fundamental role in astrochemistry because it is an intermediary in gas-phase ion-neutral reactions within cold molecular clouds. However, the impact of the environment on the chemistry of HCNH$^{+}$ remains poorly understood. With the IRAM-30 m and APEX-12 m observations, we report the first robust distribution of HCNH$^{+}$ in the Serpens filament and in Serpens South. Our data suggest that HCNH$^{+}$ is abundant in cold and quiescent regions, but is deficit in active star-forming regions. The observed HCNH$^{+}$ fractional abundances relative to H$_{2}$ range from $3.1\times 10^{-11}$ in protostellar cores to $5.9\times 10^{-10}$ in prestellar cores, and the HCNH$^{+}$ abundance generally decreases with increasing H$_{2}$ column density, which suggests that HCNH$^{+}$ coevolves with cloud cores. Our observations and modeling results suggest that the abundance of HCNH$^{+}$ in cold molecular clouds is strongly dependent on the H$_{2}$ number density. The decrease in the abundance of HCNH$^{+}$ is caused by the fact that its main precursors (e.g., HCN and HNC) undergo freeze-out as the number density of H$_{2}$ increases. However, current chemical models cannot explain other observed trends, such as the fact that the abundance of HCNH$^{+}$ shows an anti-correlation with that of HCN and HNC, but a positive correlation with that of N$_{2}$H$^{+}$ in the southern part of the Serpens South northern clump. This indicates that additional chemical pathways have to be invoked for the formation of HCNH$^{+}$ via molecules like N$_{2}$ in regions in which HCN and HNC freeze out. Both the fact that HCNH$^{+}$ is most abundant in molecular cores prior to gravitational collapse and the fact that low-$J$ HCNH$^{+}$ transitions have very low H$_{2}$ critical densities make this molecular ion an excellent probe of pristine molecular gas., Comment: 25 pages, 26 figures, accepted for publication in A&A

Cygnus X is one of the closest and most active high-mass star-forming regions in our Galaxy, making it one of the best laboratories for studying massive star formation. As part of the GLOSTAR Galactic plane survey, we performed large scale simultaneous H$_{2}$CO (1$_{1,0}$-1$_{1,1}$) spectral line and radio continuum imaging observations toward Cygnus X at $\lambda\sim$6 cm with the Karl G. Jansky Very Large Array and the Effelsberg-100 m radio telescope. Our Effelsberg observations reveal widespread H$_{2}$CO (1$_{1,0}$-1$_{1,1}$) absorption with a spatial extent of $\gtrsim$50 pc in Cygnus~X for the first time. On large scales of 4.4 pc, the relative orientation between local velocity gradient and magnetic field tends to be more parallel at H$_{2}$ column densities of $\gtrsim$1.8$\times 10^{22}$~cm$^{-2}$. On the smaller scale of 0.17 pc, our VLA+Effelsberg combined data reveal H$_{2}$CO absorption only toward three bright H{\scriptsize II} regions. Our observations demonstrate that H$_{2}$CO (1$_{1,0}$-1$_{1,1}$) is commonly optically thin. Kinematic analysis supports the assertion that molecular clouds generally exhibit supersonic motions on scales of 0.17-4.4 pc. We show a non-negligible contribution of the cosmic microwave background radiation in producing extended absorption features in Cygnus X. Our observations suggest that H$_{2}$CO ($1_{1,0}-1_{1,1}$) can trace molecular gas with H$_{2}$ column densities of $\gtrsim 5 \times 10^{21}$ cm$^{-2}$. The ortho-H$_{2}$CO fractional abundance with respect to H$_{2}$ has a mean value of 7.0$\times 10^{-10}$. A comparison of velocity dispersions on different linear scales suggests that the dominant $-3$ km s$^{-1}$ velocity component in the prominent DR21 region has nearly identical velocity dispersions on scales of 0.17-4.4 pc, which deviates from the expected behavior of classic turbulence., Comment: 27 pages, 23 figures, accepted for publication in A&A

Hub-filament systems are suggested to be the birth cradles of high-mass stars and clusters. We apply the FILFINDER algorithm to the integrated intensity maps of the 13CO (3-2) line to identify filaments in the G333 complex, and extract the velocity and intensity along the filament skeleton from moment maps. Clear velocity and density fluctuations are seen along the filaments, allowing us to fit velocity gradients around the intensity peaks. The velocity gradients fitted to the LAsMA data and ALMA data agree with each other over the scales covered by ALMA observations in the ATOMS survey. Changes of velocity gradient with scale indicate a ''funnel'' structure of the velocity field in PPV space, indicative of a smooth, continuously increasing velocity gradient from large to small scales, and thus consistent with gravitational acceleration. The typical velocity gradient corresponding to a 1 pc scale is ~1.6km/s/pc. Assuming free-fall, we estimate a kinematic mass within 1 pc of ~1190 M$_\odot$, which is consistent with typical masses of clumps in the ATLASGAL survey. We find direct evidence for gravitational acceleration from comparison of the observed accelerations to those predicted by free-fall onto dense hubs. On large scales, we find that the inflow may be driven by the larger scale structure, consistent with hierarchical structure in the molecular cloud and gas inflow from large to small scales. The hub-filament structures at different scales may be organized into a hierarchical system extending up to the largest scales probed, through the coupling of gravitational centers at different scales. We argue that the ''funnel'' structure in PPV space can be an effective probe for the gravitational collapse motions in molecular clouds. The large scale gas inflow is driven by gravity, implying that the molecular clouds in G333 complex may be in the state of global gravitational collapse.

We analyzed the 3-mm wavelength spectral line survey of 408 ATLASGAL clumps observed with the IRAM 30m-telescope, focusing on the class I methanol masers with frequencies near 84, 95 and 104.3 GHz. We detect narrow, maser-like features towards 54, 100 and 4 sources in the maser lines near 84, 95 and 104.3 GHz, respectively. Among them, fifty 84 GHz masers, twenty nine 95 GHz masers and four rare 104.3 GHz masers are new discoveries. The new detections increase the number of known 104.3 GHz masers from 5 to 9. The 95 GHz class I methanol maser is generally stronger than the 84 GHz maser counterpart. We find 9 sources showing class I methanol masers but no SiO emission, indicating that class I methanol masers might be the only signpost of protostellar outflow activity in extremely embedded objects at the earliest evolutionary stage. Class I methanol masers that are associated with sources that show SiO line wings are more numerous and stronger than those without such wings. The total integrated intensity of class I methanol masers is well correlated with the integrated intensity and velocity coverage of the SiO (2--1) emission. The properties of class I methanol masers are positively correlated with the bolometric luminosity, clump mass, peak H$_2$ column density of their associated clumps but uncorrelated with the luminosity-to-mass ratio, dust temperature, and mean H$_2$ volume density. We suggest that the properties of class I masers are related to shocks traced by SiO. Based on our observations, we conclude that class I methanol masers at 84 and 95 GHz can trace a similar evolutionary stage as H$_2$O maser, and appear prior to 6.7 and 12.2 GHz methanol and OH masers. Despite their small number, the 104.3 GHz class I masers appear to trace a short and more evolved stage compared to the other class I masers. [abridged], Comment: 23 pages, 27 figures, 8 tables, accepted for publication in A&A

FU Orionis (FUor) and EX Lupi (EXor) type objects are two groups of peculiar and rare pre-main sequence low-mass stars that are undergoing powerful accretion outbursts during their early stellar evolution. Water masers are widespread in star forming regions and are powerful probes of mass accretion and ejection, but little is known about the prevalence of them toward FUors/EXors. We perform the first systematic search for the 22.2 GHz water maser line in FUors/EXors to determine its overall incidence to perform follow-up high angular resolution observations. We used the Effelsberg 100-m radio telescope to observe the 22.2 GHz H2O maser toward a sample of 51 objects. We detect 5 water masers; 3 are associated with eruptive stars, resulting in a 6% detection rate for eruptive sources. These detections include one EXor, V512 Per (also known as SVS 13 or SVS 13A), and two FUors, Z CMa and HH 354 IRS. This is the first reported detection of water maser emission towards HH 354 IRS. We detect water maser emission in our pointing towards the FUor binary RNO 1B/1C, which most likely originates from the nearby deeply embedded source IRAS 00338+6312 (~4'', from RNO 1B/1C). Emission was also detected from H$_2$O(B) (also known as SVS 13C), a Class 0 source ~30'', from the EXor V512 Per. The peak flux density of H$_2$O(B) in our observations, 498.7 Jy, is the highest observed to date. In addition to the two non-eruptive Class 0 sources (IRAS 00338+6312 and H$_2$O(B) /SVS 13C), we detect maser emission towards one Class 0/I (HH 354 IRS) and two Class I (V512 Per and Z CMa) eruptive stars. We demonstrate the presence of 22.2 GHz water maser emission in FUor/EXor systems, opening the way to radio interferometric observations to study these eruptive stars on small scales. Comparing our data with historical observations suggest that multiple water maser flares have occurred in both V512 Per and H$_2$O(B)., Comment: 12 pages, 8 figures, accepted for publication in Astronomy & Astrophysics

Recent observations of the light component of the cosmic-ray spectrum have revealed unexpected features that motivate further and more precise measurements up to the highest energies. The Dark Matter Particle Explorer is a satellite-based cosmic-ray experiment that has been operational since December 2015, continuously collecting data on high-energy cosmic particles with very good statistics, energy resolution, and particle identification capabilities. In this work, the latest measurements of the energy spectrum of proton+helium in the energy range from 46 GeV to 464 TeV are presented. Among the most distinctive features of the spectrum, a spectral hardening at 600 GeV has been observed, along with a softening at 29 TeV measured with a 6.6{\sigma} significance. Moreover, the detector features and the analysis approach allowed for the extension of the spectral measurement up to the sub-PeV region. Even if with small statistical significance due to the low number of events, data suggest a new spectral hardening at about 150 TeV., Comment: Published on PRD

FU Orionis (FUor) and EX Lupi (EXor) type objects represent two small, but rather spectacular groups of low-mass, young eruptive stars. Outbursts of several magnitudes are observed, attributed to enhanced accretion from the circumstellar disk onto the central protostar. The host molecular environments of FUors/EXors are poorly explored due to the scarcity of systematic molecular line observations. We carried out the first dedicated survey of the molecular environments of a large sample of FUors/EXors, observing a total of 51 sources with the aim of studying the ammonia (NH$_3$) emission in their host environments. We observed the ammonia (J,K)=(1,1), (2,2), and (3,3) inversion transitions using the Effelsberg 100-m radio telescope. We derived H$_2$ column densities and dust temperatures using archival Herschel SPIRE data. We detected the (1,1) transition toward 28 sources and the (2,2) transition toward 12 sources, while the (3,3) transition was detected toward only two sources. We find kinetic temperatures between ~12 K and 21 K, ammonia column densities from $5.2\times10^{13}\,cm^{-2}$ to $3.2\times10^{15}\,cm^{-2}$, and fractional ammonia abundances with respect to H$_{2}$ from $4.7\times10^{-9}$ to $1.5\times10^{-7}$. The results are comparable to those found in infrared dark clouds (IRDCs). Kinetic analysis suggests that most of the eruptive stars in our sample reside in rather quiescent (sonic or transonic) host environments. Our NH$_3$ observations and analysis of the SPIRE dust-based H$_2$ column density maps confirm the presence of dense material toward 7 sources in our sample; additional sources might also harbour dense gas based on their NH$_2$ (2,2) detections, might indicate an earlier phase than originally classified. Based on our results, we suggest observations targeting additional molecular lines would help to refine the evolutionary classification of eruptive stars., Comment: 20 pages, 2 figures, accepted for publication in A&A

We carried out a high time-resolution, multicolour optical observing campaign for eight $\gamma$-ray detected blazars during 2010-2020. We analyze flux variations, correlations between magnitudes and colours on different timescales. Intraday variability (IDV) is detected in all eight sources of our sample. A bluer-when-brighter (BWB) chromatic trend is dominant on intraday timescales. On the short timescales, the BWB trend only shows up in ON 231, 3C 279, BL Lacertae and 1E 1458.8+2249. There is a BWB trend in 3C 279 on the long timescale. We estimate the upper limits of black hole mass for three blazars (i.e. ON 321, 1ES 1426+42.8, PKS 1510-089) using variability timescales. On April 13, 2010 a potential quasi-periodic oscillation (QPO) with the period of $P=48.67\pm13.90$ minutes is found in 1ES 1426+42.8. The light curve on March 16, 2021 further shows the existence of the QPO phenomenon. The QPO in this target deserves further observation and confirmation., Comment: 18 pages, 8 figures, accepted in MNRAS

With the IRAM 30 meter telescope, we performed observations of the $J$ = 2-1 transitions of CS, C$^{33}$S, C$^{34}$S, C$^{36}$S, $^{13}$CS, $^{13}$C$^{33}$S, and $^{13}$C$^{34}$S as well as the $J$ = 3-2 transitions of C$^{33}$S, C$^{34}$S, C$^{36}$S, and $^{13}$CS toward a large sample of 110 HMSFRs. We measured the $^{12}$C/$^{13}$C, $^{32}$S/$^{34}$S, $^{32}$S/$^{33}$S, $^{32}$S/$^{36}$S, $^{34}$S/$^{33}$S, $^{34}$S/$^{36}$S, and $^{33}$S/$^{36}$S abundance ratios with rare isotopologs of CS, thus avoiding significant saturation effects. With accurate distances obtained from parallax data, we confirm previously identified $^{12}$C/$^{13}$C and $^{32}$S/$^{34}$S gradients as a function of galactocentric distance (RGC). In the CMZ, $^{12}$C/$^{13}$C ratios are higher than suggested by a linear fit to the disk values as a function of RGC. While $^{32}$S/$^{34}$S ratios near the Galactic center and in the inner disk are similar, this is not the case for $^{12}$C/$^{13}$C, when comparing central values with those near RGC of 5 kpc. As was already known, there is no $^{34}$S/$^{33}$S gradient but the average ratio of 4.35~$\pm$~0.44 derived from the $J$ = 2-1 transition lines of C$^{34}$S and C$^{33}$S is well below previously reported values. A comparison between solar and local interstellar $^{32}$S/$^{34}$S and $^{34}$S/$^{33}$S ratios suggests that the Solar System may have been formed from gas with a particularly high $^{34}$S abundance. For the first time, we report positive gradients of $^{32}$S/$^{33}$S, $^{34}$S/$^{36}$S, $^{33}$S/$^{36}$S, and $^{32}{\rm S}/^{36}{\rm S}$ in our Galaxy. The predicted $^{12}$C/$^{13}$C ratios from the latest GCE models are in good agreement with our results. While $^{32}$S/$^{34}$S and $^{32}$S/$^{36}$S ratios show larger differences at larger RGC, $^{32}$S/$^{33}$S ratios show an offset across the entire inner 12 kpc of the Milky Way., Comment: HMSFRs: high-mass star-forming regions. CMZ: central molecular zone. GCE: Galactic chemical evolution. 68 pages, 12 tables, 18 figures. Accepted for publication in A&A

Context. While over 1000 supernova remnants (SNRs) are estimated to exist in the Milky Way, only less than 400 have been found to date. In the context of this apparent deficiency, more than 150 SNR candidates were recently identified in the D-configuration Very Large Array (VLA-D) continuum images of the 4--8 GHz global view on star formation (GLOSTAR) survey, in the Galactic longitude range $-2^\circ

As part of the GLOSTAR survey we have used the VLA in its B-configuration to observe the part of the Galactic plane between longitudes of 28d and 36d and latitudes from -1d to +1d at the C-band (4--8 GHz). To reduce the contamination of extended sources that are not well recovered by our coverage of the (u, v)-plane we discarded short baselines that are sensitive to emission on angular scales $<4"$. The resulting radio continuum images have an angular resolution of 1.0", and sensitivity of $\sim60 \mu$Jy~beam$^{-1}$; making it the most sensitive radio survey covering a large area of the Galactic plane with this angular resolution. An automatic source extraction algorithm was used in combination with visual inspection to identify a total of 3325 radio sources. A total of 1457 radio sources are $\geq7\sigma$ and comprise our highly reliable catalog; 72 of these are grouped as 22 fragmented sources, e.g., multiple components of an extended and resolved source. To explore the nature of the catalogued radio sources we searched for counterparts at millimeter and infrared wavelengths. Our classification attempts resulted in 93 HII region candidates, 104 radio stars, 64 planetary nebulae, while most of the remaining radio sources are suggested to be extragalactic sources. We investigated the spectral indices ($\alpha$, $S_\nu\propto\nu^\alpha$) of radio sources classified as HII region candidates and found that many have negative values. This may imply that these radio sources represent young stellar objects that are members of the star clusters around the high mass stars that excite the HII regions, but not these HII regions themselves. By comparing the peak flux densities from the GLOSTAR and CORNISH surveys we have identified 49 variable radio sources, most of them with an unknown nature. Additionally, we provide the list of 1866 radio sources detected within 5 to 7$\sigma$ levels., Comment: 25 pages, 15 figures, and 6 tables, Accepted for publication in the Astronomy \& Astrophysics

We report the discovery of widespread maser emission in non-metastable inversion transitions of NH$_3$ toward various parts of the Sagittarius B2 molecular cloud/star forming region complex: We detect masers in the $J,K = $ (6,3), (7,4), (8,5), (9,6), and (10,7) transitions toward Sgr B2(M) and Sgr B2(N), an NH$_3$ (6,3) maser in Sgr B2(NS), and NH$_3$ (7,4), (9,6), and (10,7) masers in Sgr B2(S). With the high angular resolution data of the Karl G. Jansky Very Large Array (JVLA) in A-configuration we identify 18 maser spots. Nine maser spots arise from Sgr B2(N), one from Sgr B2(NS), five from Sgr B2(M), and three in Sgr B2(S). Compared to our Effelsberg single dish data, the JVLA data indicate no missing flux. The detected maser spots are not resolved by our JVLA observations. Lower limits to the brightness temperature are $>$3000~K and reach up to several 10$^5$~K, manifesting the lines' maser nature. In view of the masers' velocity differences with respect to adjacent hot molecular cores and/or UCH{\scriptsize II} regions, it is argued that all the measured ammonia maser lines may be associated with shocks caused either by outflows or by the expansion of UCH{\scriptsize II} regions. Overall, Sgr B2 is unique in that it allows us to measure many NH$_3$ masers simultaneously, which may be essential to elucidate their so far poorly understood origin and excitation., Comment: 17 pages, 14 figures, 7 tables. Accepted for publication in A&A Letter

More than a century after the performance of the oil drop experiment, the possible existence of fractionally charged particles FCP still remains unsettled. The search for FCPs is crucial for some extensions of the Standard Model in particle physics. Most of the previously conducted searches for FCPs in cosmic rays were based on experiments underground or at high altitudes. However, there have been few searches for FCPs in cosmic rays carried out in orbit other than AMS-01 flown by a space shuttle and BESS by a balloon at the top of the atmosphere. In this study, we conduct an FCP search in space based on on-orbit data obtained using the DArk Matter Particle Explorer (DAMPE) satellite over a period of five years. Unlike underground experiments, which require an FCP energy of the order of hundreds of GeV, our FCP search starts at only a few GeV. An upper limit of $6.2\times 10^{-10}~~\mathrm{cm^{-2}sr^{-1} s^{-1}}$ is obtained for the flux. Our results demonstrate that DAMPE exhibits higher sensitivity than experiments of similar types by three orders of magnitude that more stringently restricts the conditions for the existence of FCP in primary cosmic rays., Comment: 19 pages, 6 figures, accepted by PRD

Smoke detection has become a significant task in associated industries due to the close relationship between the petrochemical industry's smoke emission and its safety production and environmental damage. There are several production situations in the real industrial production environment, including complete combustion of exhaust gas, inadequate combustion of exhaust gas, direct emission of exhaust gas, etc. We discovered that the datasets used in previous research work can only determine whether smoke is present or not, not its type. That is, the dataset's category does not map to the real-world production situations, which are not conducive to the precise regulation of the production system. As a result, we created a multi-categories smoke detection database that includes a total of 70196 images. We further employed multiple models to conduct the experiment on the proposed database, the results show that the performance of the current algorithms needs to be improved and demonstrate the effectiveness of the proposed database.

Class II methanol (CH$_{3}$OH) masers are amongst the clearest signposts of recent high-mass star formation (HMSF). A complete catalogue outlines the distribution of star formation in the Galaxy, the number of young star-forming cores, and the physical conditions of their environment. The Global View on Star Formation (GLOSTAR) survey, which is a blind survey in the radio regime of 4$-$8 GHz, maps the Galactic mid-plane in the radio continuum, 6.7 GHz methanol line, the 4.8 GHz formaldehyde line, and several radio recombination lines. We present the analysis of the observations of the 6.7 GHz CH$_{3}$OH maser transition using data from the D-configuration of the Very Large Array (VLA). We analyse the data covering Galactic longitudes from $-2^{\circ}< l <60^{\circ}$ and Galactic latitudes of $|\textit{b}|<1^{\circ}$. We detect a total of 554 methanol masers, out of which 84 are new, and catalogue their positions, velocity components, and integrated fluxes. With a typical noise level of $\sim$18 mJy beam$^{-1}$, this is the most sensitive unbiased methanol survey for methanol masers to date. We search for dust continuum and radio continuum associations, and find that 97% of the sources are associated with dust, and 12% are associated with radio continuum emission., Comment: Accepted in A&A July 18, 2022

Biomarker detection is the key to identifying health risks. However, designing sensitive biosensors in a single-use mode for disease diagnosis remains a major challenge. Here, we report sub-monolayer biolasers with remarkable repeatability for ultrasensitive and disposable biomarker detection. The biolaser sensors are designed by employing the telecom optical fibers as distributed optical microcavities and pushing the gain molecules down to the sub-monolayer level. We observe a status transition from the monolayer biolaser to the sub-monolayer biolaser by tuning the specific conjugation. By reducing the fluorophores down to the threshold density (~ 3.2 x 10-13 mol/cm2), we demonstrate an ultimate sensitivity of sub-monolayer biolaser with six orders of magnitude enhancement compared with the monolayer biolasers. We further achieved ultrasensitive immunoassay for Parkinson's disease biomarker, alpha-synuclein, with a lower limit of detection of 0.32 pM in serum. This biosensor with massive fabrication capability at ultralow cost provides a general method for the ultrasensitive disposable biodetection of disease biomarkers., Comment: 27 pages, 15 figures

We carried out a cyanopolyyne line survey towards a large sample of HMSFRs using the Shanghai Tian Ma 65m Radio Telescope (TMRT). Our sample consisted of 123 targets taken from the TMRT C band line survey. It included three kinds of sources, namely those with detection of the 6.7 GHz CH3OH maser alone, with detection of the radio recombination line (RRL) alone, and with detection of both (hereafter referred to as Maser-only, RRL-only, and Maser-RRL sources, respectively). We detected HC3N in 38 sources, HC5N in 11 sources, and HC7N in G24.790+0.084, with the highest detection rate being found for Maser-RRL sources and a very low detection rate found for RRL-only sources. Their column densities were derived using the rotational temperature measured from the NH3 lines. And we constructed and fitted the far-infrared (FIR) spectral energy distributions. Based on these, we derive their dust temperatures, H2 column densities, and abundances of cyanopolyynes relative to H2. The detection rate, the column density, and the relative abundance of HC3N increase from Maser-only to Maser-RRL sources and decrease from Maser-RRL to RRL-only sources. This trend is consistent with the proposed evolutionary trend of HC3N under the assumption that our Maser-only, Maser-RRL, and RRL-only sources correspond to massive young stellar objects, ultra-compact HII regions, and normal classical HII regions, respectively. Furthermore, a statistical analysis of the integrated line intensity and column density of HC3N and shock-tracing molecules (SiO, H2CO) enabled us to find positive correlations between them. This suggests that HC3N may be another tracer of shocks, and should therefore be the subject of further observations and corresponding chemical simulations. Our results indirectly support the idea that the neutral--neutral reaction between C2H2 and CN is the dominant formation pathway of HC3N., Comment: 23 pages, 5 figures, 4 tables, Accepted to A&A

Winds from massive stars have recently been deemed promising sites for investigating relativistic particle acceleration. Particularly, the resulting bow shock from the interaction of the winds of runaway stars with interstellar matter has been observed at multiple wavelengths. Here we investigate the O4If star, BD+433654, the bow shock of which is, so far, the only one proven to radiate both thermally and non-thermally at radio frequencies. We also consider NGC7635 as a bow shock candidate and examine its apex for indications of thermal and non-thermal radio emission. We observed both sources with the VLA at 4-8 GHz and 8-12 GHz, and with the Effelsberg telescope at 4-8 GHz. We analysed data from both telescopes individually and combined, obtained their spectral index maps and calculated their Spectral Energy Distributions. We present the first high-resolution maps of radio emission from NGC7635. We find that both emit non-thermal emission in the radio regime, with the clearest evidence for NGC7635. Our results are less conclusive for BD+433654, as the emission from its bow shock becomes weaker and fainter at higher radio frequencies. Our results extend the previous radio results for the BD+433654 bow shock to higher frequencies. Modelling of our data for both sources shows that accelerated electrons at the wind termination shock are a plausible source for the non-thermal radio emission, but energetics arguments suggest that any non-thermal X-ray and $\gamma$-ray emission could be significantly below existing upper limits. Enhanced synchrotron emission from compressed Galactic cosmic rays in the radiative bow shock could also explain the radio emission from the BD+433654 bow shock but not NGC7635. Non-detection of point-like radio emission from BD+433654 puts an upper limit on the mass-loss rate of the star that is lower than values quoted in the literature. [abridged], Comment: 17 pages, 13 figures

Gravitational collapse is one of the most important processes in high-mass star formation. Compared with the classic blue-skewed profiles, redshifted absorption against continuum emission is a more reliable method to detect inward motions within high-mass star formation regions. We aim to test if methanol transitions can be used to trace infall motions within high-mass star formation regions. Using the Effelsberg-100 m, IRAM-30 m, and APEX-12 m telescopes, we carried out observations of 37 and 16 methanol transitions towards two well-known collapsing dense clumps, W31C (G10.6-0.4) and W3(OH), to search for redshifted absorption features or inverse P-Cygni profiles. Redshifted absorption is observed in 14 and 11 methanol transitions towards W31C and W3(OH), respectively. The infall velocities fitted from a simple two-layer model agree with previously reported values derived from other tracers, suggesting that redshifted methanol absorption is a reliable tracer of infall motions within high-mass star formation regions. Our observations indicate the presence of large-scale inward motions, and the mass infall rates are roughly estimated to be $\gtrsim$10$^{-3}$ $M_{\odot}$yr$^{-1}$, which supports the global hierarchical collapse and clump-fed scenario. With the aid of bright continuum sources and the overcooling of methanol transitions leading to enhanced absorption, redshifted methanol absorption can trace infall motions within high-mass star formation regions hosting bright H{\scriptsize II} regions., Comment: 21 pages, 13 figures, 5 tables. Accepted for publication in A&A

Molecular maser lines are signposts of high-mass star formation, probing excitation and kinematics of very compact regions in the close environment of young stellar objects and providing useful targets for trigonometric parallax measurements. Only a few NH$_{3}$ (9,6) masers were known so far, and their origin is still poorly understood. Here we aim to find new NH$_{3}$ (9,6) masers to provide a better observational basis to study their role in high-mass star-forming regions. We carried out NH$_{3}$ (9,6) observations toward Cepheus A and G34.26$+$0.15 with the Effelsberg-100 m telescope and the Karl G. Janksy Very Large Array. We discovered new NH$_{3}$ (9,6) masers in Cep A and G34.26$+$0.15, which increases the number of high-mass star-forming regions hosting NH$_{3}$ (9,6) masers from five to seven. Long term monitoring (20 months) at Effelsberg shows that the intensity of the (9,6) maser in G34.26$+$0.15 is decreasing, while the Cep A maser remains stable. Compared to the Effelsberg data and assuming linear variations between the epochs of observation, the JVLA data indicate no missing flux. This suggests that the NH$_3$ (9,6) emission arises from single compact emission regions that are not resolved by the interferometric measurements. As JVLA imaging shows, the NH$_{3}$ (9,6) emission in Cep A originates from a sub-arcsecond sized region, slightly to the west of the peak position of the 1.36\,cm continuum object, HW2. In G34.26$+$0.15, three NH$_{3}$ (9,6) maser spots are observed: one is close to the head of the cometary ultracompact \h2 region C and the other two are emitted from a compact region to the west of the hypercompact \h2 region A. The newly found (9,6) masers appear to be related to outflows. Higher angular resolution of JVLA and VLBI observations are needed to provide more accurate positions and constraints for pumping scenarios., Comment: 10 pages, 6 figures, 3 tables. Publicated in A&A

The Nearby Evolved Stars Survey (NESS) is a volume-complete sample of $\sim$850 Galactic evolved stars within 3\,kpc at (sub-)mm wavelengths, observed in the CO $J = $ (2$-$1) and (3$-$2) rotational lines, and the sub-mm continuum, using the James Clark Maxwell Telescope and Atacama Pathfinder Experiment. NESS consists of five tiers, based on distances and dust-production rate (DPR). We define a new metric for estimating the distances to evolved stars and compare its results to \emph{Gaia} EDR3. Replicating other studies, the most-evolved, highly enshrouded objects in the Galactic Plane dominate the dust returned by our sources, and we initially estimate a total DPR of $4.7\times 10^{-5}$ M$_\odot$ yr$^{-1}$ from our sample. Our sub-mm fluxes are systematically higher and spectral indices are typically shallower than dust models typically predict. The 450/850 $\mu$m spectral indices are consistent with the blackbody Rayleigh--Jeans regime, suggesting a large fraction of evolved stars have unexpectedly large envelopes of cold dust., Comment: 20 pages, 13 figures, 5 tables, accepted for publications in MNRAS

Atomic gas in the diffuse interstellar medium (ISM) is organized in filamentary structures. These structures usually host cold and dense molecular clumps. The Galactic magnetic field is considered to play an important role in the formation of these clumps. Our goal is to explore the role of the magnetic field in the HI - H$_{2}$ transition process. We targeted a filamentary cloud where gas transitions from atomic to molecular. This cloud is located at the edges of an expanding structure, known as the North Celestial Pole Loop (NCPL). We probed the magnetic field properties of the cloud with optical polarization observations. We performed multi-wavelength spectroscopic observations of different species in order to probe the gas phase properties of the cloud. We identified two distinct sub-regions within the cloud. One of the regions hosts purely atomic gas, while the other is dominated by molecular gas although most of it is CO-dark. The estimated plane-of-the-sky magnetic field strength between the two regions remains constant within uncertainties and lies in the range 20 ~ 30$~\mu$G. The total magnetic field strength does not scale with density which implies that gas is compressed along the field lines. We also found that turbulence is sub-Alfv\'enic. The HI velocity gradients are in general perpendicular to the mean magnetic field orientation, except for the region close to the CO clump where they tend to become parallel. The latter is likely related to gas undergoing gravitational infall. The magnetic field morphology of the target cloud is parallel to the HI column density structure of the cloud in the atomic region, while it tends to become perpendicular to the HI structure in the molecular region. If this is verified in more cases it has important consequences for the ISM magnetic field modeling with HI data., Comment: Accepted for publication in A&A

We mapped the kinetic temperature structure of two massive star-forming regions, N113 and N159W, in the Large Magellanic Cloud (LMC). We have used $\sim$1\hbox{$\,.\!\!^{\prime\prime}$}6\,($\sim$0.4\,pc) resolution measurements of the para-H$_2$CO\,$J_{\rm K_ aK_c}$\,=\,3$_{03}$--2$_{02}$, 3$_{22}$--2$_{21}$, and 3$_{21}$--2$_{20}$ transitions near 218.5\,GHz to constrain RADEX non-LTE models of the physical conditions. The gas kinetic temperatures derived from the para-H$_2$CO line ratios 3$_{22}$--2$_{21}$/3$_{03}$--2$_{02}$ and 3$_{21}$--2$_{20}$/3$_{03}$--2$_{02}$ range from 28 to 105\,K in N113 and 29 to 68\,K in N159W. Distributions of the dense gas traced by para-H$_2$CO agree with those of the 1.3\,mm dust and \emph{Spitzer}\,8.0\,$\mu$m emission, but do not significantly correlate with the H$\alpha$ emission. The high kinetic temperatures ($T_{\rm kin}$\,$\gtrsim$\,50\,K) of the dense gas traced by para-H$_2$CO appear to be correlated with the embedded infrared sources inside the clouds and/or YSOs in the N113 and N159W regions. The lower temperatures ($T_{\rm kin}$\,$<$\,50\,K) are measured at the outskirts of the H$_2$CO-bearing distributions of both N113 and N159W. It seems that the kinetic temperatures of the dense gas traced by para-H$_2$CO are weakly affected by the external sources of the H$\alpha$ emission. The non-thermal velocity dispersions of para-H$_2$CO are well correlated with the gas kinetic temperatures in the N113 region, implying that the higher kinetic temperature traced by para-H$_2$CO is related to turbulence on a $\sim$0.4\,pc scale. The dense gas heating appears to be dominated by internal star formation activity, radiation, and/or turbulence. It seems that the mechanism heating the dense gas of the star-forming regions in the LMC is consistent with that in Galactic massive star-forming regions located in the Galactic plane., Comment: Accepted for publication in A&A