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we present the results of 850 μm polarization and c18o (3 - 2) line observations toward the western hub-filament structure (w-hfs) of the dark streamer in ic 5146 using the james clerk maxwell telescope scuba-2/pol-2 and harp instruments. we aim to investigate how the relative importance of the magnetic field, gravity,... | evolution of the hub-filament structures in ic 5146 in the context of the energy balance of gravity, turbulence, and magnetic field |
we present the turbulence spectra of magnetic and electron density fluctuations in situ measured by voyager 1 in the local interstellar medium from 2012 to 2019. the magnetic spectrum shows a kolmogorov power law with a one-dimensional power-law index -5/3 at mk ≤ 10-8.8, where k is a wavenumber and m is the unit meter... | turbulence spectra of electron density and magnetic field fluctuations in the local interstellar medium |
the ordered magnetic field observed via polarised synchrotron emission in nearby disc galaxies can be explained by a mean-field dynamo operating in the diffuse interstellar medium (ism). additionally, vertical-flux initial conditions are potentially able to influence this dynamo via the occurrence of the magnetorotatio... | dynamo saturation in direct simulations of the multi-phase turbulent interstellar medium |
we present high-precision optical polarimetric observations of the black hole x-ray binary cygnus x-1 that span several cycles of its 5.6-day orbital period. the week-long observations on two telescopes located in opposite hemispheres allowed us to track the evolution of the polarization within one orbital cycle with t... | peering into the tilted heart of cyg x-1 with high-precision optical polarimetry |
our simultaneous three-colour (bvr) polarimetric observations of the low-mass black hole x-ray binary v404 cyg show a small but statistically significant change of polarization degree (δp ∼ 1 per cent) between the outburst in 2015 june and the quiescence. the polarization of v404 cyg in the quiescent state agrees withi... | high-precision optical polarimetry of the accreting black hole v404 cyg during the 2015 june outburst |
we describe the first complete polarimetric data set of the entire outburst of a low-mass black hole x-ray binary system and discuss the constraints for geometry and radiative mechanisms it imposes. during the decaying hard state, when the optical flux is dominated by the non-thermal component, the observed polarizatio... | disc and wind in black hole x-ray binary maxi j1820+070 observed through polarized light during its 2018 outburst |
fluctuation dynamos are thought to play an essential role in the evolution of magnetized galaxies, saturating within ∼0.01 gyr and thus potentially acting as seeds for large-scale mean-field dynamos. however, unambiguous observational confirmation of the fluctuation dynamo action in a galactic environment is still miss... | magnetic fields in elliptical galaxies: an observational probe of the fluctuation dynamo action |
context. observations of synchrotron emission at low radio frequencies reveal a labyrinth of polarised galactic structures. however, the explanation for the wealth of structures remains uncertain due to the complex interactions between the interstellar medium and the magnetic field. a multi-tracer approach to the analy... | faraday tomography of lotss-dr2 data. i. faraday moments in the high-latitude outer galaxy and revealing loop iii in polarisation |
we solve the linearised vlasov-fokker-planck (vfp) equation to show that heat flow or an electrical current in a magnetized collisional plasma is unstable to the growth of a circularly polarised transverse perturbation to a zeroth order uniform magnetic field. the braginskii (1965) transport equations exhibit the same ... | instability in a magnetised collisional plasma driven by a heat flow or a current |
we investigate how observations of synchrotron intensity fluctuations can be used to probe the sonic and alfvénic mach numbers of interstellar turbulence, based on mock observations performed on simulations of magnetohydrodynamic turbulence. we find that the structure function slope and a diagnostic of anisotropy that ... | radio synchrotron fluctuation statistics as a probe of magnetized interstellar turbulence |
understanding how the galactic magnetic field threads the multiphase interstellar medium (ism) remains a considerable challenge, as different magnetic field tracers probe dissimilar phases and field components. we search for evidence of a common magnetic field shared between the ionized and neutral ism by comparing 1.4... | a comparison of multiphase magnetic field tracers in a high galactic latitude region of the filamentary interstellar medium |
when the pulsar signal propagates in the interstellar medium (ism), the high frequency and low frequency components of the signal reach the radio telescope with a certain delay. therefore, the pulsar signal will appear energy dispersion, which will broaden the pulse profile, decrease the signal to noise ratio, and even... | research on a coherent dedispersion algorithm for pulsar baseband data |
pulsars are rotating neutron stars emitting lighthouse-like beams. owing to their unique properties, pulsars are a unique astrophysical tool to test general relativity, inform on matter in extreme conditions, and probe galactic magnetic fields. understanding pulsar physics and emission mechanisms is critical to these a... | determining the rotation direction in pulsars |
much of our present observational knowledge of the interstellar magnetic field of our galaxy comes from two different sources, both of which involve mechanisms operating at radio wavelengths: the first one is the faraday rotation of linearly-polarized radio waves propagating through the magneto-ionic interstellar mediu... | faraday tomography: a new, three-dimensional probe of the interstellar magnetic field |
we present a comprehensive study of the rotational and emission properties of psr j0738-4042 using a combination of observations taken by the deep space network, hartebeesthoek, parkes (murriyang) and molonglo observatories between 1972 and 2023. our timing of the pulsar is motivated by previously reported profile/spin... | rotational and radio emission properties of psr j0738-4042 over half a century |
we present simultaneous optical and near-infrared (nir) polarimetric results for the black hole binary v404 cyg spanning the duration of its seven-day-long optically brightest phase of its 2015 june outburst. the simultaneous r- and ks -band light curves showed almost the same temporal variation except for the isolated... | no evidence of intrinsic optical/near-infrared linear polarization for v404 cygni during its bright outburst in 2015: broadband modeling and constraint on jet parameters |
wolf-rayet stars have strong, hot winds, with mass-loss rates at least a factor of 10 greater than their o-star progenitors, although their terminal wind speeds are similar. in this paper, we use the technique of multiband linear polarimetry to extract information on the global asymmetry of the wind in a sample of 47 b... | a multiwavelength search for intrinsic linear polarization in wolf-rayet winds |
a critical challenge in the observation of the redshifted 21 cm line is its separation from bright galactic and extragalactic foregrounds. in particular, the instrumental leakage of polarized foregrounds, which undergo significant faraday rotation as they propagate through the interstellar medium, may harmfully contami... | constraining polarized foregrounds for eor experiments. ii. polarization leakage simulations in the avoidance scheme |
recently we have demonstrated that high-precision polarization observations can detect the polarization resulting from the rotational distortion of a rapidly rotating b-type star. here, we investigate the extension of this approach to an a-type star. linear-polarization observations of α oph (a5iv) have been obtained o... | the rotation of α oph investigated using polarimetry |
we report the detection of a curved magnetic field in the ring-like shell of the bubble n4, derived from near-infrared polarization of reddened diskless stars located behind this bubble. the magnetic field in the shell is curved and parallel to the ring-like shell, and its strength is estimated to be ∼ 120 μ {{g}} in t... | a curved magnetic field in the ring-like shell of bubble n4 |
aims: we report on the follow-up of the extremely bright long gamma-ray burst (grb) grb 210619b with optical polarimetry.methods: we conducted optopolarimetric observations of the optical afterglow of grb 210619b in the sdss-r band in the time window ∼5967 − 8245 s after the burst, using the robopol instrument at the s... | grb 210619b optical afterglow polarization |
the detection of the redshifted cosmological 21-cm line signal requires the removal of the galactic and extragalactic foreground emission, which is orders of magnitude brighter anywhere in the sky. foreground cleaning methods currently used are efficient in removing spectrally smooth components. however, they struggle ... | simulations of galactic polarized synchrotron emission for epoch of reionization observations |
linearly polarized emission is described, in general, in terms of the stokes parameters q and u, from which the polarization intensity and polarization angle can be determined. although the polarization intensity and polarization angle provide an intuitive description of the polarization, they are affected by the limit... | advanced diagnostics for the study of linearly polarized emission. i. derivation |
we present 850 μm polarization and c18o (3-2) molecular line observations toward the x-shaped nebula in the california molecular cloud using james clerk maxwell telescope (jcmt)'s scuba-2/pol-2 and harp instruments. the 850 μm emission shows that the observed region includes two elongated filamentary structures (fil1 a... | magnetic fields and fragmentation of filaments in the hub of california-x |
ammonia molecules have an important role in the radiation-induced chemistry that occurs on grains in the cold interstellar medium and leads to the formation of nitrogen containing molecules. such grains and surfaces are primarily covered by water ices; however, these conditions allow the growth of solid ammonia films a... | spontaneous polarization of thick solid ammonia films |
diagnostics of polarized emission provide us with valuable information on the galactic magnetic field and the state of turbulence in the interstellar medium, which cannot be obtained from synchrotron intensity alone. in paper i, we derived polarization diagnostics that are rotationally and translationally invariant in ... | advanced diagnostics for the study of linearly polarized emission. ii. application to diffuse interstellar radio synchrotron emission |
due to the inevitable accumulation of observational information in the direction of the line of sight, it is difficult to measure the local magnetic field of magnetohydrodynamic (mhd) turbulence. however, a correct understanding of the local magnetic field is a prerequisite for reconstructing the galactic 3d magnetic f... | studying the local magnetic field and anisotropy of magnetic turbulence by synchrotron polarization derivative |
we present version x of the hammurabi package, the healpix-based numeric simulator for galactic polarized emission. improving on its earlier design, we have fully renewed the framework with modern c++ standards and features. multithreading support has been built in to meet the growing computational workload in future r... | hammurabi x: simulating galactic synchrotron emission with random magnetic fields |
collisional energy transfer under cold conditions is of great importance from the fundamental and applicative point of view. here, we investigate low temperature collisions of the sh- anion with he. we have generated a three-dimensional potential energy surface (pes) for the sh-(x1σ+)-he(1s) van der waals complex. the ... | cold collisions of sh- with he: potential energy surface and rate coefficients |
we observed seven epochs of spectropolarimetry in optical wavelengths for the type iib sn 2011hs, ranging from -3 to +40 d with respect to v-band maximum. a high degree of interstellar polarization was detected (up to ∼3 per cent), with a peak lying blueward of 4500 å. similar behaviours have been seen in some type ia ... | the 3d shape of type iib sn 2011hs |
on the basis of the modern understanding of mhd turbulence, we propose a new way of using synchrotron radiation, namely using synchrotron intensity gradients for tracing astrophysical magnetic fields. we successfully test the new technique using synthetic data obtained with the 3d mhd simulations and provide the demons... | erratum: “synchrotron intensity gradients as tracers of interstellar magnetic fields” (2017, apj, 842, 1, 30) |
currently, about 100 carbon-containing molecules have been detected in interstellar and circumstellar environments, and this list includes isomeric substances. in most cases, the minimum energy principle is able to explain the ratio of abundances of the isomeric compounds but in some cases is not. trying to rationalize... | polarizability of isomeric and related interstellar compounds in the aspect of their abundance |
the radio arc is a system of organized nonthermal filaments (ntfs) located within the galactic center (gc) region of the milky way. recent observations of the radio arc ntfs revealed a magnetic field that alternates between being parallel and rotated with respect to the orientation of the filaments. this pattern is in ... | analyzing the intrinsic magnetic field in the galactic center radio arc |
based on statistical analysis of synchrotron polarization intensity, we study the anisotropic properties of compressible magnetohydrodynamic (mhd) turbulence. the second-order normalized structure function, quadrupole ratio modulus, and anisotropic coefficient are synergistically used to characterize the anisotropy of ... | studying the anisotropy of compressible magnetohydrodynamic turbulence by synchrotron polarization intensity |
observations of synchrotron polarization at multiple frequencies in the presence of faraday rotation can provide a way to reconstruct the 3d magnetic field distribution. in this paper we compare the well known faraday tomography (ft) technique to a new approach, synchrotron polarization gradients (spgs). we compare the... | a comparison between faraday tomography and synchrotron polarization gradients |
magnetic fields play important roles in many astrophysical processes. however, there is no universal diagnostic for the magnetic fields in the interstellar medium (ism) and each magnetic tracer has its limitation. any new detection method is thus valuable. theoretical studies have shown that submillimetre fine-structur... | polarization of submillimetre lines from interstellar medium |
bright-rimmed clouds (brcs) form on the edges of h ii regions affected by high-energy radiation from a central ionizing source. the uv radiation from the ionizing source results in compression and ionization, causing either cloud disruption or further star formation. in this work, we present r-band polarization measure... | magnetic fields in multiple bright-rimmed clouds in different directions of h ii region ic 1396 |
aims: our aim is to study the mass transfer, accretion environment, and wind outflows in the ss 433 system, concentrating on the so-called stationary lines.methods: we used archival high-resolution (x-shooter) and low-resolution (emmi) optical spectra, new optical multi-filter polarimetry, and low-resolution optical sp... | an optical spectroscopic and polarimetric study of the microquasar binary system ss 433 |
we present our observational results of the 0.87 mm polarized dust emission in the class 0 protostar b335 obtained with the atacama large millimeter/submillimeter array (alma) at a 0"2 (20 au) resolution. we compared our data at 0.87 mm with those at 1.3 mm from the alma archive. the observed polarization orientations ... | transition from ordered pinched to warped magnetic field on a 100 au scale in the class 0 protostar b335 |
we made r-band polarization measurements of 234 stars towards the direction of the mbm 33-39 cloud complex. the distance of the mbm 33-39 complex was determined as 120 ± 10 pc using polarization results and near-infrared photometry from the 2mass survey. the magnetic field geometry of the individual clouds inferred fro... | polarization of seven mbm clouds at high galactic latitude |
cool evolved stars are known to be significant contributors to the enrichment of the interstellar medium through their dense and dusty stellar winds. high resolution observations of these outflows have shown them to possess high degrees of morphological complexity. we observed the asymptotic giant branch (agb) star ep ... | a detailed view on the circumstellar environment of the m-type agb star ep aquarii. i. high-resolution alma and sphere observations |
we present a study of the relative orientation between the magnetic field and elongated cloud structures for the ρ oph a and ρ oph e regions in l1688 in the ophiuchus molecular cloud. combining inferred magnetic field orientation from hawc+ 154 μm observations of polarized thermal emission with column density maps crea... | hawc+/sofia polarimetry in l1688: relative orientation of magnetic field and elongated cloud structure |
context. both simulations and observations of the interstellar medium show that the study of the relative orientations between filamentary structures and the magnetic field can bring new insight into the role played by magnetic fields in the formation and evolution of filaments and in the process of star formation.aims... | fildreams. ii. application to the analysis of the relative orientations between filaments and the magnetic field in four herschel fields |
fast radio bursts (frbs) are energetic millisecond phenomena in the radio band. polarimetric studies of repeating frbs indicate that many of these sources occupy extreme and complex magnetoionized environments. recently, a frequency-dependent depolarization has been discovered in several repeating frbs. however, the te... | temporal evolution of depolarization and magnetic field of fast radio burst 20201124a |
we present near-infrared polarimetric observations of the black hole x-ray binaries swift j1357.2-0933 and a0620-00. in both sources, recent studies have demonstrated the presence of variable infrared synchrotron emission in quiescence, most likely from weak compact jets. for swift j1357.2-0933, we find that the synchr... | polarized synchrotron emission in quiescent black hole x-ray transients |
highly reddened type ia supernovae (sne ia) with low total-to-selective visual extinction ratio values, rv, also show peculiar linear polarization wavelength dependencies with peak polarizations at short wavelengths (λmax ≲ 0.4 μm). it is not clear why sightlines to sne ia display such different continuum polarization ... | spectropolarimetry of galactic stars with anomalous extinction sightlines |
bow shocks and related density enhancements produced by the winds of massive stars moving through the interstellar medium provide important information regarding the motions of the stars, the properties of their stellar winds, and the characteristics of the local medium. since bow-shock nebulae are aspherical structure... | polarization simulations of stellar wind bow-shock nebulae - i. the case of electron scattering |
the next generation balloon-borne large aperture submillimeter telescope (blast-tng) is a submillimeter mapping experiment planned for a 28 day long-duration balloon (ldb) flight from mcmurdo station, antarctica during the 2018-2019 season. blast-tng will detect submillimeter polarized interstellar dust emission, traci... | preflight characterization of the blast-tng receiver and detector arrays |
we present an analysis of archival multi-frequency very large array monitoring data of the two-image gravitational lens system class b1600+434, including the polarization properties at 8.5 ghz. from simulating radio light curves incorporating realistic external variability in image a, we find time delays consistent at ... | the time delay of class b1600+434 from vla multi-frequency and polarization monitoring |
afterglows of gamma-ray bursts (grbs) are emitted from expanding forward shocks, which are expected to have magnetic fields much stronger than the interstellar field, although the origin of the field is a long-standing problem. two field amplification mechanisms, plasma kinetic instabilities and magnetohydrodynamic ins... | synchrotron polarization of gamma-ray burst afterglow shocks with hydrodynamic-scale turbulent magnetic field |
interstellar dust grains are often aligned. if the grain alignment direction varies along the line of sight, the thermal emission becomes circularly polarized. in the diffuse interstellar medium, the circular polarization at far-infrared and submillimeter wavelengths is predicted to be very small, and probably unmeasur... | on far-infrared and submillimeter circular polarization |
we present a study of the continuum polarization over the 400-600 nm range of 19 sne ia obtained with fors at the vlt. we separate them into those that show na i d lines at the velocity of their hosts and those that do not. continuum polarization of the sodium sample near maximum light displays a broad range of values,... | continuum foreground polarization and na i absorption in type ia sne |
synchrotron intensity and polarization gradients (sig and spg), proposed by lazarian et al. and lazarian & yuen, present a new way to recover the mean magnetic field direction in the plane of the sky. to measure the magnetization level, lazarian et al. suggested that the methods used in the context of the "velocity... | synchrotron intensity and polarization gradients: tools to obtain the magnetization level in a turbulent medium |
we establish a theoretical framework for solving the equations of motion for an arbitrarily shaped, inhomogeneous dust particle in the presence of radiation pressure. the repeated scattering problem involved is solved using a state-of-the-art volume integral equation-based t-matrix method. a fortran implementation of t... | dynamics of small particles in electromagnetic radiation fields: a numerical solution |
the potential energy surface is computed at the explicitly correlated coupled cluster with simple, second and perturbative triple excitation method (ccsd(t)-f12) in connection with the augmented-correlation consistent-polarized valence triple zeta (aug-cc-pvtz) gaussian basis set for the neh+ -he system. the calculatio... | collisional rates based on the first potential energy surface of the neh+ -he system |
context. many galaxies contain magnetic fields supported by galactic dynamo action. the investigation of these magnetic fields can be helpful for understanding galactic evolution; however, nothing definitive is known about magnetic fields in ring galaxies.aims: here we investigate large-scale magnetic fields in a previ... | magnetic fields in ring galaxies |
we compare two rotationally invariant decomposition techniques on linear polarization data: the spin-2 spherical harmonic decomposition in two opposite parities, the e- and b-mode, and the multiscale analysis of the gradient of linear polarization, |\nabla p|. we demonstrate that both decompositions have similar proper... | a new perspective on turbulent galactic magnetic fields through comparison of linear polarization decomposition techniques |
the quantum mechanical treatment of quadrupole radiation due to bremsstrahlung exact to all orders in the coulomb interaction of two nonrelativistically colliding charged spin-0 and unpolarized spin-1/2 particles is presented. we calculate the elements of the quadrupole tensor, and present analytical solutions for the ... | exact theory of nonrelativistic quadrupole bremsstrahlung |
we have investigated the grain alignment and dust properties towards the direction of the cluster ngc 2345 using the multiband optical polarimetric observations. for the majority of the stars, the observed polarization is found to be due to the interstellar medium with average values of maximum polarization and wavelen... | polarization, polarizing efficiency, and grain alignment towards the direction of the cluster ngc 2345 |
in the laboratory, the photo-and thermochemical evolution of ices, made of simple molecules of astrophysical relevance, always leads to the formation of semi-refractory water-soluble organic residues. targeted searches for specific molecules do reveal the notable presence of two families of important molecular ''bricks... | interstellar ices: a possible scenario for symmetry breaking of extraterrestrial chiral organic molecules of prebiotic interest |
radiative transfer models were developed to understand the optical polarizations in edge-on galaxies, which are observed to occur even outside the geometrically thin dust disk, with a scale height of ≈0.2 kpc. in order to reproduce the vertically extended polarization structure, we find that it is essential to include ... | polarization as a probe of thick dust disks in edge-on galaxies: application to ngc 891 |
we present results based on the optical r-band observations of the polarization of 280 stars distributed toward the dark globule ldn 1225. parallaxes from gaia data release 2 along with the polarization data of ∼200 stars have been used to (a) constrain the distance of ldn 1225 as 830 ± 83 pc, (b) determine the contrib... | polarimetric and photometric investigation of the dark globule ldn 1225: distance, extinction law, and magnetic fields |
magnetic fields play an important role in shaping the structure and evolution of the interstellar medium (ism) of galaxies, but the details of this relationship remain unclear. with ska1, the 3d structure of galactic magnetic fields and its connection to star formation will be revealed. a highly sensitive probe of the ... | magnetic field tomography in nearby galaxies with the square kilometre array |
we present the new open-source c++-based python library costuum that can be used to generate infrared absorption and emission coefficients for arbitrary mixtures of spheroidal dust grains that are (partially) aligned with a magnetic field. we outline the algorithms underlying the software, demonstrate the accuracy of o... | costuum: polarized thermal dust emission by magnetically oriented spheroidal grains |
we provide a procedure for identification of dominating compressible and alfvenic mhd modes or isotropic turbulence in synchrotron emission polarization maps of galactic objects. the results for the region of north galactic pole, orion molecular cloud complex and the star-forming complex cygnus x are presented. | identification of mhd compressible modes in interstellar plasma with synchrotron emission polarization |
the discovery of interstellar communication signals is complicated by the presence of radio interference. consequently, interstellar communication signals are hypothesized to have properties that favor discovery in high levels of local planetary radio interference. a hypothesized type of interstellar signal, delta-t de... | radio interference reduction in interstellar communications: methods and observations |
pre-stellar cores within molecular clouds provide the very initial conditions in which stars are formed. fest 1-457 is a prototypical starless core and the most chemically evolved among those isolated, embedded in the most pristine part of the pipe nebula, the bowl. we use the iram 30 m telescope and the pdbi to study ... | a correlation between chemistry, polarization, and dust properties in the pipe nebula starless core fest 1-457 |
multiband linear polarimetric observations of 125 stars in the region of the cluster ngc 1817 have been carried out intending to study properties of interstellar dust and grains in that direction. the polarization is found to be wavelength-dependent, being maximum in the v band with an average value of 0.95%. the foreg... | broadband linear polarization in the region of the open star cluster ngc 1817 |
we study the effects of ambipolar diffusion (ad) on hydromagnetic turbulence. we consider the regime of large magnetic prandtl number, relevant to the interstellar medium. in most of the cases, we use the single-fluid approximation where the drift velocity between charged and neutral particles is proportional to the lo... | ambipolar diffusion in large prandtl number turbulence |
the nature of dust in the diffuse interstellar medium can be best investigated by means of reddening curves where only a single interstellar cloud lies between the observer and the background source. published reddening curves often suffer from various systematic uncertainties. we merged a sample of 820 reddening curve... | dark dust. iii. the high-quality single-cloud reddening curve sample: scrutinizing extinction curves in the milky way |
we present b-, v-, r-, and i-band linear polarimetric observations of 73 stars in the direction of open star cluster casado alessi 1 (hereafter alessi 1). we aim to use polarimetry as a tool to investigate the properties and distribution of dust grains toward the direction of the cluster. the polarimetric observations ... | optical linear polarization toward the open star cluster casado alessi 1 |
this paper presents the results of full polarization observations of the massive star-forming region w75n, conducted with ~3″ spatial resolutions at 345 ghz using the submillimeter array. the magnetic field structures in the dense cores of the region are derived using the linearly polarized continuum emission. the over... | submillimeter observations of magnetic fields in massive star-forming region w75n |
investigating interstellar (is) dust properties in external galaxies is important not only to infer the intrinsic properties of astronomical objects but also to understand the star/planet formation in the galaxies. from the non-milky way-like extinction and interstellar polarization (isp) observed in reddened type ia s... | diversity of dust properties in external galaxies confirmed by polarization signals from type ii supernovae |
the large-scale magnetic fields observed in spiral disc galaxies are often thought to result from dynamo action in the disc plane. however, the increasing importance of faraday depolarization along any line of sight towards the galactic plane suggests that the strongest polarization signal may come from well above (∼0.... | the origin of the structure of large-scale magnetic fields in disc galaxies |
we present a new optical polarimetric catalog for the small magellanic cloud (smc). it contains a total of 7207 stars, located in the northeast (ne) and wing sections of the smc and part of the magellanic bridge. this new catalog is a significant improvement compared to previous polarimetric catalogs for the smc. we us... | a new optical polarization catalog for the small magellanic cloud: the magnetic field structure |
although it was found that the feh lines exist in the spectra of some stars, none of the spectral features in the interstellar medium (ism) have been assigned to this molecule. we suggest that iron atoms interact with hydrogen and produce fe-h nanoparticles which sometimes contain many h atoms. we calculate infrared sp... | missing fe: hydrogenated iron nanoparticles |
we present 230 ghz continuum polarization observations with the atacama large millimeter/submillimeter array at a resolution of 0.″1 (~540 au) in the high-mass star-forming regions w51 e2 and e8. these observations resolve a network of core-connecting dust lanes, marking a departure from earlier coarser, more spherical... | a multiscale picture of the magnetic field and gravity from a large-scale filamentary envelope to core-accreting dust lanes in the high-mass star-forming region w51 |
accurately measuring the magnetic field in the ism is essential for understanding star formation processes. we searched archival data of the submillimeter array for evidence of circular polarization in common molecular tracers, most notably co. this circular polarization possibly arises from anisotropic resonant scatte... | non-zeeman circular polarization of molecular spectral lines in the ism |
we analyse the observational signatures of galactic magnetic fields that are self-consistently generated in magnetohydrodynamic simulations of the interstellar medium through turbulence driven by supernova (sn) explosions and differential rotation. in particular, we study the time evolution of the faraday rotation meas... | observational signatures of galactic turbulent dynamos |
the intense line emission of oh masers is a perfect tracer of regions where new stars are born aswell as of evolved stars, shedding large amounts of processed matter into the interstellar medium. from ska deep surveys at 18 cm, where the maser lines from the ground-state of the oh molecule arise, we predict the discove... | oh masers in the milky way and local group galaxies in the ska era |
a high level electronic structure calculation of the born-oppenheimer (bo) potential, scalar-relativistic effect and adiabatic correction is performed for the x1σ+ ground state of astronomically important isotopologues of the arh+ cation. particular attention is paid to both short and long distances, where experimental... | an accurate ab initio electronic structure calculation for interstellar argonium |
sn 1993j is one of the best-studied type iib supernovae. spectropolarimetric data analyses were published over two decades ago at a time when the field of supernova spectropolarimetry was in its infancy. here, we present a new analysis of the spectropolarimetric data of sn 1993j and an improved estimate of its interste... | the shape of sn 1993j re-analysed |
how many bits of information can a single photon carry? intuition says "one", but this is incorrect. with an alphabet based on the photon's time of arrival, energy, and polarization, several bits can be encoded. in this introduction to photon information efficiency, we explain how to calculate the maximum number of bit... | interstellar communication. v. introduction to photon information efficiency (in bits per photon) |
recent \herschel\ and \planck\ observations of submillimeter dust emission revealed the omnipresence of filamentary structures in the interstellar medium (ism). the ubiquity of filaments in quiescent clouds as well as in star-forming regions indicates that the formation of filamentary structures is a natural product of... | properties of interstellar filaments as derived from $herschel$, $planck$, and molecular line observations |
faraday tomography, the study of the distribution of extended polarized emission by strength of faraday rotation, is a powerful tool for studying magnetic fields in the interstellar medium of our galaxy and nearby galaxies. the strong frequency dependence of faraday rotation results in very different observational stre... | the power of low frequencies: faraday tomography in the sub-ghz regime |
density functional theory calculations, using the b3lyp parameterisation, were performed to determine structures, vibrational frequencies, and binding energies for complexation of ni+ and ni2+ cations with benzene and naphthalene molecules and clusters. the calculations employed the stuttgart basis set with ecp pseudo ... | structures and binding energies for complexations of different spin states of ni+ and ni2+ to aromatic molecules |
asymptotic giant branch (agb) stars are, together with supernovae, the main contributors of stellar dust to the interstellar medium (ism). dust grains formed by agb stars are thought to be large. however, as dust nucleation and growth within their outflows are still not understood, the dust-grain size distribution (gsd... | chemical modelling of dust-gas chemistry within agb outflows - ii. effect of the dust-grain size distribution |
in this work we performed a spectral energy distribution (sed) analysis in the optical/infrared band of the host galaxy of a proto-brightest bluster galaxy (bcg, nvss j103023 + 052426) in a proto-cluster at z = 1.7. we found that it features a vigorous star formation rate (sfr) of ∼570 m⊙/yr and a stellar mass of m*∼3.... | multi-wavelength study of a proto-bcg at z = 1.7 |
we present bvri polarimetric measurements of 23 stars in the direction of the open cluster ngc 6709. fifteen stars display wavelength-dependence of polarization which is typically due to selective extinction in the interstellar medium and could be fitted to the serkwoski equation. based on these stars, we obtained an a... | interstellar extinction and polarization of stars in the open cluster ngc 6709 |
models of interstellar dust alignment assume that dust grains are elongated, but none of these models explain why dust grains should be elongated. on the other hand, models of interstellar dust grain growth assume that dust grains are spherical and not elongated. we show that when dusty plasma effects and the dipole mo... | why interstellar ice dust grains should be elongated |
rotational inelastic scattering of silyl cyanide (sih3cn) molecule with helium (he) atoms is investigated. three-dimensional potential energy surface (3d-pes) for the sih3cn-he interacting system is carried out. the ab initio 3d-pes is computed using explicitly correlated coupled cluster approach with single, double, a... | inelastic scattering of interstellar silyl cyanide (sih3cn) by helium atoms : cross-sections and rate coefficients for a- and e-sih3cn |
high precision polarization measurements, such as those from the planck satellite, open new opportunities for the study of the magnetic field structure as traced by polarimetric measurements of the interstellar dust emission. the polarization parameters suffer from bias in the presence of measurement noise. it is criti... | polarization measurement analysis. iii. analysis of the polarization angle dispersion function with high precision polarization data |
the alignment of interstellar dust grains with magnetic fields provides a key method for measuring the strength and morphology of the fields. in turn, this provides a means to study the role of magnetic fields from diffuse gas to dense star-forming regions. the physical mechanism for aligning the grains has been a long... | a far-infrared observational test of the directional dependence in radiative grain alignment |
monitoring thermal processes occurring in molecular films on surfaces can provide insights into physical events such as morphology changes and phase transitions. here, we demonstrate that temperature-programmed contact potential difference (tp-δcpd) measurements employed by a kelvin probe under ultrahigh vacuum conditi... | the role of thermal history on spontaneous polarization and phase transitions of amorphous solid water films studied by contact potential difference measurements |
polican is a near-infrared imaging linear polarimeter developed for the cananea near-infrared camera (canica) at the 2.1 m telescope of the guillermo haro astrophysical observatory (oagh) located in cananea, sonora, méxico. polican is mounted ahead of canica and consist of a rotating super-achromatic (1-2.7 μm) half-wa... | polican: a near-infrared imaging polarimeter at the 2.1m oagh telescope |
considering the spatially separated polarization radiation and faraday rotation regions to simulate complex interstellar media, we study synchrotron polarization gradient techniques' measurement capabilities. we explore how to trace the direction of projected magnetic field of emitting-source region at the multifrequen... | gradient measurement of synchrotron polarization diagnostic: application to spatially separated emission and faraday rotation regions |
filaments are considered to be basic structures, and molecular clouds consist of filaments. filaments are often observed as extending in the direction perpendicular to the interstellar magnetic field. the structure of filaments has been studied based on a magnetohydrostatic equilibrium model. here we simulate the expec... | polarization structure of filamentary clouds |
we present photometry, spectra, and spectropolarimetry of supernova (sn) 2014ab, obtained through ~200 d after peak brightness. sn 2014ab was a luminous type iin sn (mv < -19.14 mag) discovered after peak brightness near the nucleus of its host galaxy, vv 306c. pre-discovery upper limits constrain the time of explos... | sn 2014ab: an aspherical type iin supernova with low polarization |
faraday rotation measures (rms) should be interpreted with caution because there could be multiple magneto-ionized medium components that contribute to the net faraday rotation along sightlines. we introduce a simple test using galactic diffuse polarized emission that evaluates whether structures evident in rm observat... | distant probes of rotation measure structure: where is the faraday rotation towards the magellanic leading arm? |
complete studies of the radiative processes of thermal emission from the amorphous dust from microwave through far-infrared wavebands are presented by taking into account, self-consistently for the first time, the standard two-level systems (tls) model of amorphous materials. the observed spectral energy distributions ... | thermal emission from the amorphous dust: an alternative possibility of the origin of the anomalous microwave emission |
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