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the nsf's karl g. jansky very large array (vla) is used to observe 122 magnetic cataclysmic variables (mcvs) during three observing semesters (13b, 15a, and 18a). we report radio detections of 33 stars with fluxes in the range 6-8031 μjy. twenty-eight stars are new radio sources, increasing the number of radio detected... | radio observations of magnetic cataclysmic variables |
aims: observations of millimeter wavelength radio recombination lines (mm-rrls) are used to search for h ii regions in an unbiased way that is complementary to many of the more traditional methods previously used (e.g., radio continuum, far-infrared colors, maser emission). the mm-rrls can be used to derive physical pr... | atlasgal-selected massive clumps in the inner galaxy. iv. millimeter hydrogen recombination lines from associated h ii regions |
we conducted a very long baseline array (vlba) observation of the low mass active galactic nucleus (agn) in galaxy ngc 4293 (z = 0.003). the object is associated with a low-ionization nuclear emission-line region (liner). its black hole mass is estimated as ~105 or ${\sim}10^7 \, \mathrm{m}_\odot$. the vlba 1.5 ghz ima... | a compact symmetric ejection from the low mass agn in the liner galaxy ngc 4293 |
the non-thermal radio emission of main-sequence early-type stars is a signature of stellar magnetism. we present multiwavelength (1.6-16.7 ghz) atca measurements of the early-type magnetic star ρ-=ophc, which is a flat-spectrum non-thermal radio source. the ρ-=ophc radio emission is partially circularly polarized with ... | the auroral radio emission of the magnetic b-type star ρ-=ophc |
context. the s-type asymptotic giant branch (agb) star π1 gru has a known companion at a separation of 2.̋7 (≈400 au). previous observations of the circumstellar envelope (cse) show strong deviations from spherical symmetry. the envelope structure, including an equatorial torus and a fast bipolar outflow, is rarely see... | the extended molecular envelope of the asymptotic giant branch star π1 gruis as seen by alma. i. large-scale kinematic structure and co excitation properties |
we report the discovery of a population of deeply embedded protostellar candidates in the 20 km s-1 cloud, one of the massive molecular clouds in the central molecular zone (cmz) of the milky way, using interferometric submillimeter continuum and h2o maser observations. the submillimeter continuum emission shows five 1... | deeply embedded protostellar population in the 20 km s-1 cloud of the central molecular zone |
the thermal emission of trans-neptunian objects and centaurs has been observed at mid- and far-infrared wavelengths—with the biggest contributions coming from the spitzer and herschel space observatories—and the brightest ones also at submillimeter and millimeter wavelengths. these measurements allowed to determine the... | trans-neptunian objects and centaurs at thermal wavelengths |
we constrain the emission mechanisms responsible for the prodigious electromagnetic output generated by active galactic nuclei (agns) and their host galaxies with a novel state-of-the-art agn radio-to-x-ray spectral energy distribution model fitting code (arxsed). arxsed combines multiple components to fit the spectral... | disentangling the agn and star formation contributions to the radio-x-ray emission of radio-loud quasars at 1 < z < 2 |
context. the quiet solar corona emits meter-wave thermal bremsstrahlung. coronal radio emission can only propagate above that radius, rω, where the local plasma frequency equals the observing frequency. the radio interferometer low frequency array (lofar) observes in its low band (10-90 mhz) solar radio emission origin... | lofar observations of the quiet solar corona |
reanalyzing cassini radio observations performed during jupiter's flyby of 2000-2001, we study the internal (rotational) versus external (solar wind) control of jupiter's radio emissions, from kilometer to decameter wavelengths, and the relations between the different auroral radio components. for that purpose, we buil... | jupiter's auroral radio emissions observed by cassini: rotational versus solar wind control, and components identification |
we report atacama large millimeter/submillimeter array (alma) observations of a one-sided, high-velocity (∼80 km s-1) co(j = 2\to 1) jet powered by the intermediate-mass protostellar source serpens smm1-a. the highly collimated molecular jet is flanked at the base by a wide-angle cavity; the walls of the cavity can be ... | an extremely high velocity molecular jet surrounded by an ionized cavity in the protostellar source serpens smm1 |
the majority of searches for radio emission from exoplanets have to date focused on short period planets, i.e., the so-called hot jupiter type planets. however, these planets are likely to be tidally locked to their host stars and may not generate sufficiently strong magnetic fields to emit electron cyclotron maser emi... | a search for radio emission from exoplanets around evolved stars |
to study a molecular-cloud-scale chemical composition, we conducted a mapping spectral line survey toward the galactic molecular cloud w3(oh), which is one of the most active star-forming regions in the perseus arm. we conducted our survey through the use of the nobeyama radio observatory 45 m telescope, and observed t... | molecular-cloud-scale chemical composition. ii. mapping spectral line survey toward w3(oh) in the 3 mm band |
we present a deep radio-polarimetric observation of the stellar bow shock eb27 associated with the massive star bd+43○3654. this is the only stellar bow shock confirmed to have non-thermal radio emission. we used the jansky very large array in s band (2-4 ghz) to test whether this synchrotron emission is polarized. the... | high-sensitivity radio study of the non-thermal stellar bow shock eb27 |
we use the 21-cm emission-line data from the deep investigation of neutral gas origin-very large array (dingo-vla) project to study the atomic hydrogen gas h i of the universe at redshifts z < 0.1. results are obtained using a stacking analysis, combining the h i signals from 3622 galaxies extracted from 267 vla poi... | measuring cosmic density of neutral hydrogen via stacking the dingo-vla data |
the atacama large millimeter/submillimeter array (alma) serendipitously detected h2o $j_{k_{\rm a}, k_{\rm c}} = 10_{2,9}$-93, 6 emission at 321 ghz in ngc 1052. this is the first submillimeter maser detection in a radio galaxy and the most luminous 321 ghz h2o maser known to-date with the isotropic luminosity of $1090... | alma detection of 321 ghz water maser emission in the radio galaxy ngc 1052 |
we have carried out a study of radio emission from a small sample of magnetic o- and b-type stars using the giant metrewave radio telescope, with the goal of investigating their magnetospheres at low frequencies. these are the lowest frequency radio measurements ever obtained of hot magnetic stars. the observations wer... | detection of 610-mhz radio emission from hot magnetic stars |
context. the nançay radioheliograph (nrh) routinely produces snapshot images of the full sun (field of view ~3 r⊙) at 6 or 10 frequencies between 150 and 450 mhz, with typical resolution 3 arcmin and time cadence 0.2 s. combining visibilities from the nrh and from the giant meterwave radio telescope (gmrt) allows us to... | the structure of solar radio noise storms |
we use gemini near-infrared integral field spectrograph (nifs) observations of the inner 3.5 × 3.5 kpc2 of the radio galaxy cygnus a to map the gas excitation and kinematics at a spatial resolution of 200 pc. the emission of the ionized gas shows a biconical morphology, with half-opening angle of 45○ and oriented along... | powerful multiphase outflows in the central region of cygnus a |
we present a simple, unified model that can explain two of the brightest, large-scale, diffuse, polarized radio features in the sky, the north polar spur (nps) and the fan region, along with several other prominent loops. we suggest that they are long, magnetized, and parallel filamentary structures that surround the l... | a unified model for the fan region and the north polar spur: a bundle of filaments in the local galaxy |
context. class i methanol masers are known to be associated with shocked outflow regions around massive protostars, indicating a possible link between the maser properties and those of their host clumps.aims: the main goals of this study are (1) to search for new class i methanol masers, (2) to statistically study the ... | atlasgal: 3 mm class i methanol masers in high-mass star formation regions |
we present subarcsecond angular resolution observations carried out with the submillimeter array (sma) at 880 μm centered at the b0-type protostar ggd27 mm1, the driving source of the parsec scale hh 80-81 jet. we constrain its polarized continuum emission to ≲0.8% at this wavelength. its submillimeter spectrum is domi... | the circumestellar disk of the b0 protostar powering the hh 80-81 radio jet |
jupiter's magnetosphere is often said to be rotationally driven, with strong centrifugal stresses due to large spatial scales and a rapid planetary rotation period. while the solar wind is therefore expected to have a relatively small influence on jupiter's magnetosphere and aurora, there is considerable observational ... | solar wind interaction with jupiter's magnetosphere: a statistical study of galileo in situ data and modeled upstream solar wind conditions |
herein, we present 12co (j = 1-0) and 13co (j = 1-0) emission-line observations via the forest unbiased galactic plane imaging survey with the nobeyama 45 m telescope (fugin) toward spitzer bubble n4. we observed clouds at three discrete velocities: 16, 19, and 25 km s-1. their masses were 0.1 × 104 m ⊙, 0.3 × 104 m ⊙,... | fugin: molecular gas in spitzer bubble n4—possible evidence for a cloud-cloud collision as a trigger of massive star formations |
electrostatic (es) waves generated in space plasmas, e.g., langmuir and ion-acoustic waves, are subject to multiple applications, such as plasma diagnosis, generation of radio emissions, and the acceleration and heating of resonant populations. the dispersion properties of these waves are well known for idealized plasm... | about the effects of solar wind suprathermal electrons on electrostatic waves |
coherent radio emission via electron cyclotron maser emission (ecme) from hot magnetic stars was discovered more than two decades ago, but the physical conditions that make the generation of ecme favourable remain uncertain. only recently was an empirical relation, connecting ecme luminosity with the stellar magnetic f... | testing a scaling relation between coherent radio emission and physical parameters of hot magnetic stars |
merging binary neutron stars are thought to be formed predominantly via isolated binary evolution. in this standard formation scenario, the first-born neutron star goes through a recycling process and might be rapidly spinning during the final inspiral, whereas the second-born star is expected to have effectively zero ... | characterizing astrophysical binary neutron stars with gravitational waves |
deep and wide-field optical photometric observations along with multiwavelength archival data sets have been employed to study the physical properties of the cluster ngc 6910. the study also examines the impact of massive stars on their environment. the age, distance, and reddening of the cluster are estimated to be ∼4... | unveiling the physical conditions in ngc 6910 |
context. level population inversion of hydrogen atoms in ionized gas may lead to stimulated emission of hydrogen recombination lines, and the level populations can in turn be affected by powerful stimulated emissions.aims: in this work the interaction of the radiation fields and the level population inversion of hydrog... | inverted level populations of hydrogen atoms in ionized gas |
we mapped the kinetic temperature structure of the orion molecular cloud 1 (omc-1) with para-h2co (jkakc = 303-202, 322-221, and 321-220) using the apex 12 m telescope. this is compared with the temperatures derived from the ratio of the nh3 (2, 2)/(1, 1) inversion lines and the dust emission. using the radex non-lte m... | kinetic temperature of massive star-forming molecular clumps measured with formaldehyde. iii. the orion molecular cloud 1 |
we performed a multiwavelength study toward the infrared dark cloud (irdc) g34.43+0.24. new maps of 13co j = 1-0 and c18o j = 1-0 were obtained from the purple mountain observatory (pmo) 13.7 m radio telescope. at 8 μm (spitzer-irac), irdc g34.43+0.24 appears to be a dark filament extended by 18‧ along the north-south ... | gas kinematics and star formation in the filamentary irdc g34.43+0.24 |
to probe star formation (sf) processes, we present results of an analysis of the molecular cloud g35.20-0.74 (hereafter mcg35.2) using multi-frequency observations. the mcg35.2 is depicted in a velocity range of 30-40 km s-1. an almost horseshoe-like structure embedded within the mcg35.2 is evident in the infrared and ... | star formation activity in the molecular cloud g35.20-0.74: onset of cloud-cloud collision |
we report the first 5σ detection of h i 21 cm emission from a star-forming galaxy at redshift z ~ 1.3 (nearly 9 billion years ago) using upgraded giant metrewave radio telescope (ugmrt). this is the highest redshift h i detection in emission from an individual galaxy to date. the emission is strongly boosted by the gra... | detection of h i 21 cm emission from a strongly lensed galaxy at z 1.3 |
the discovery that many classical novae produce detectable gev γ-ray emission has raised the question of the role of shocks in nova eruptions. here, we use radio observations of nova v809 cep (nova cep 2013) with the jansky very large array to show that it produced non-thermal emission indicative of particle accelerati... | shocks and dust formation in nova v809 cep |
we present a multiwavelength study of the h ii region sh 2-301 (s301) using deep optical data, near-infrared data, radio continuum data, and other archival data at longer wavelengths. a cluster of young stellar objects (ysos) is identified in the northeast (ne) direction of s301. the hα and radio continuum images trace... | sh 2-301: a blistered h ii region undergoing star formation |
glasses have a wide variety of applications in different types of devices, including solid-state lasers, fiber-optic amplifiers, medical imaging, radiation dosimeter, solar cells, neutron imaging, and scintillators. among several rare-earth (re) ions, ce3+ exhibits short decay time and offers promising scintillation wh... | synthesis and characterization of cef3−doped (74.5-x)p2o5:20li2o:5al2o3:x(gdf3, laf3 and yf3) glasses |
aims: ar scorpii is unique amongst known white dwarf binaries in showing powerful pulsations extending to radio frequencies. here we aim to investigate the multi-frequency radio emission of ar sco in detail, in order to constrain its origin and emission mechanisms.methods: we present interferometric radio frequency ima... | vla radio observations of ar scorpii |
we mapped the kinetic temperature structure of two massive star-forming regions, n113 and n159w, in the large magellanic cloud (lmc). we have used ~1.′′6 (~0.4 pc) resolution measurements of the para-h2co jkakc = 303-202, 322-221, and 321-220 transitions near 218.5 ghz to constrain radex non local thermodynamic equilib... | kinetic temperature of massive star-forming molecular clumps measured with formaldehyde. iv. the alma view of n113 and n159w in the lmc |
we present the results from a survey, designed to investigate the accretion process of massive young stellar objects (mysos) through near-infrared narrow-band imaging using the h2 ν=1-0 s(1) transition filter. a sample of 353 myso candidates was selected from the red msx source survey using photometric criteria at long... | a survey of extended h2 emission from massive ysos |
context. highly collimated jets and wide-angle outflows are two related components of the mass-ejection activity associated with stellar birth. despite decades of research, the relation between these two components remains poorly understood.aims: we study the relation between the jet and the outflow in the iras 04166+2... | anatomy of the internal bow shocks in the iras 04166+2706 protostellar jet |
we present the results of a wideband (720-2400 mhz) study of psr b1821-24a (j1824-2452a, m28a), an energetic millisecond pulsar (msp) visible in radio, x-rays and γ-rays. in radio, the pulsar has a complex average profile that spans ≳85% of the spin period and exhibits strong evolution with observing frequency. for the... | a broadband radio study of the average profile and giant pulses from psr b1821-24a |
context. the opacity of the ionosphere prevents comprehensive earth-based surveys of low frequency ν ≲ 10 mhz astrophysical radio emissions. the limited available data in this frequency regime show a downturn in the mean sky brightness at ν ≲ 3 mhz in a divergence from the synchrotron emission power-law that is observe... | the l = 2 spherical harmonic expansion coefficients of the sky brightness distribution between 0.5 and 7 mhz |
detection of the global h i 21 cm signal from the cosmic dawn and the epoch of reionization is the key science driver for several ongoing ground-based and future ground-/space-based experiments. the crucial spectral features in the global 21 cm signal (turning points) occur at low radio frequencies ≲ 100 {{mhz}}. in ad... | the effects of the ionosphere on ground-based detection of the global 21 cm signal from the cosmic dawn and the dark ages |
the recently discovered colliding-wind binary (cwb) apep has been shown to emit luminously from radio to x-rays, with the emission driven by a binary composed of two wolf-rayet (wr) stars of one carbon-sequence (wc8) and one nitrogen-sequence (wn4-6b). mid-infrared imaging revealed a giant spiral dust plume that is rem... | au-scale radio imaging of the wind collision region in the brightest and most luminous non-thermal colliding wind binary apep |
we have performed a multi-wavelength study of the mid-infrared bubble s44 to investigate the origin of isolated high-mass star(s) and the star-formation process around the bubble formed by the h ii region. we report on the results of new co observations (12co, 13co j = 1-0, and 12co j = 3-2) toward the isolated bubble ... | co observations toward the isolated mid-infrared bubble s44: external triggering of o-star formation by a cloud-cloud collision |
a multiwavelength observing campaign of the t tauri star (tts) gm aur was undertaken in 2019 december. this campaign obtained swift x-ray and nuv fluxes, hst nuv spectra, lcogt ${u}^{{\prime} }> ${g}^{{\prime} }> ${r}^{{\prime} }> ${i}^{{\prime} }> and tess photometry, chiron hα spectra, atacama large milli... | testing the potential for radio variability in disks around t tauri stars with observations and chemical modeling |
context. this study is a follow up to the previous analysis of lower-angular resolution data in which the kinematics and structure of the circumstellar envelope (cse) around the s-type asymptotic giant branch (agb) star π1 gruis were investigated. the agb star has a known companion (at a separation of 400 au) that cann... | the extended molecular envelope of the asymptotic giant branch star π1 gruis as seen by alma. ii. the spiral-outflow observed at high-angular resolution |
understanding the origins of stellar radio emission can provide invaluable insight into the strength and geometry of stellar magnetic fields and the resultant space weather environment experienced by exoplanets. here, we present the first model capable of predicting radio emission through the electron cyclotron maser i... | simulating radio emission from low-mass stars |
we present the longest term timing study so far of three rotating radio transients (rrats) - j1819-1458, j1840-1419, and j1913+1330 - performed using the lovell, parkes, and green bank telescopes over the past decade. we study long-term and short-term variations of the pulse emission rate from these rrats and report a ... | a long-term study of three rotating radio transients |
we present the first optical polarimetric study of the two transitional pulsars psr j1023+0038 and xss j12270-4859. this work is focused on the search for intrinsically linearly polarised optical emission from the two systems. to this aim, we carried out multiband optical (bvri) and near-infrared (nir; jhk) photo-polar... | different twins in the millisecond pulsar recycling scenario: optical polarimetry of psr j1023+0038 and xss j12270-4859 |
we present the first results from the malt-45 (millimetre astronomer's legacy team-45 ghz) galactic plane survey. we have observed 5 square degrees (l = 330°-335°, b = ±0.5°) for spectral lines in the 7 mm band (42-44 and 48-49 ghz), including cs (1-0), class i ch3oh masers in the 7(0,7)-6(1,6) a+ transition and sio (1... | malt-45: a 7 mm survey of the southern galaxy - i. techniques and spectral line data |
we present the results of meerkat radio observations of 11 nearby nova-like cataclysmic variables (cvs). we have detected radio emission from im eri, rw sex, v3885 sgr, and v603 aql. while rw sex, v3885 sgr, and v603 aql had been previously detected, this is the first reported radio detection of im eri. our observation... | a meerkat survey of nearby nova-like cataclysmic variables |
the 10.7 cm radio flux (f10.7) is widely used as a proxy for solar uv forcing of the upper atmosphere. however, radio emissions at other centimetric wavelengths have been routinely monitored since the 1950 s, thereby offering prospects for building proxies that may be better tailored to space weather needs. here we adv... | the 30 cm radio flux as a solar proxy for thermosphere density modelling |
we present high-angular-resolution radio observations of the arches cluster in the galactic centre, one of the most massive young clusters in the milky way. the data were acquired in two epochs and at 6 and 10 ghz with the karl g. jansky very large array. the rms noise reached is three to four times better than during ... | radio observations of massive stars in the galactic centre: the arches cluster |
context. to constrain present star formation models, we need to simultaneously establish the dynamical and physical properties of disks and jets around young stars.aims: we previously observed the star-forming region g16.59-0.05 through interferometric observations of both thermal and maser lines, and identified a high... | a 10-m⊙ yso with a keplerian disk and a nonthermal radio jet |
the arecibo ultra-deep survey (auds) is a blind h i survey aimed at detecting galaxies beyond the local universe in the 21-cm emission line of neutral hydrogen (h i). the arecibo l-band feed array (alfa) was used to image an area of 1.35 deg2 to a redshift depth of 0.16, using a total on-source integration time of over... | the arecibo ultra-deep survey |
we report the detection of widespread ch2ohcho and hoch2ch2oh emission in galactic center giant molecular cloud sagittarius b2 using the shanghai tianma 65 m radio telescope. our observations show for the first time that the spatial distribution of these two important prebiotic molecules extends over 15 arcmin, corresp... | widespread presence of glycolaldehyde and ethylene glycol around sagittarius b2 |
context. electron-cyclotron maser emission (ecme) is the favored mechanism for solar radio spikes and has been investigated extensively since the 1980s. most studies relevant to solar spikes employ a loss-cone-type distribution of energetic electrons, generating waves mainly in the fundamental x/o mode (x1/o1), with a ... | harmonic electron-cyclotron maser emissions driven by energetic electrons of the horseshoe distribution with application to solar radio spikes |
although significant progress has been achieved in recent surveys of the magnetism in massive stars, the origin of the detected magnetic fields remains to be the least understood topic in their studies. we present an analysis of 61 high-resolution spectropolarimetric observations of 36 systems with o-type primaries, am... | are magnetic fields universal in o-type multiple systems? |
solar flares show remarkable variety in the energy partitioning between thermal and nonthermal components. those with a prominent nonthermal component but only a modest thermal one are particularly well suited for study of the direct effect of the nonthermal electrons on plasma heating. here, we analyze such a well-obs... | spatiotemporal energy partitioning in a nonthermally dominated two-loop solar flare |
the magnetic and thermal evolution of neutron stars is a very complex process with many non-linear interactions. for a decent understanding of neutron star physics, these evolutions cannot be considered isolated. a brief overview is presented, which describes the main magneto-thermal interactions that determine the fat... | magneto-thermal evolution of neutron stars with emphasis to radio pulsars |
low radio frequencies are favourable for the identification of emission from non-thermal processes such as synchrotron emission. the massive protostellar jet associated with iras 18162-2048 (also known as the hh80-81 system) has been imaged at low radio frequencies: 325, 610 and 1300 mhz, using the giant metrewave radi... | detection of non-thermal emission from the massive protostellar jet hh80-81 at low radio frequencies using gmrt |
in the centre of our galaxy lies a supermassive black hole, identified with the radio source sagittarius a⋆. this black hole has an estimated mass of around 4 million solar masses. although sagittarius a⋆ is quite dim in terms of total radiated energy, having a luminosity that is a factor of 1010 lower than its eddingt... | examining molecular clouds in the galactic centre region using x-ray reflection spectra simulations |
we study cool neutral gas traced by nad absorption in 140 local (z < 0.1) early-type red geyser galaxies. these galaxies show unique signatures in spatially resolved strong line emission maps that have been interpreted as large-scale active galactic nucleus-driven ionized winds. to investigate the possible fuel sour... | signatures of inflowing gas in red geyser galaxies hosting radio active galactic nuclei |
the solar atmosphere contains thermal plasma at a wide range of temperatures. this plasma is often quantified, in both observations and models, by a differential emission measure (dem). the dem is a distribution of the thermal electron density squared over temperature. in observations, the dem is computed along a line ... | gyroresonance and free-free radio emissions from multithermal multicomponent plasma |
we detect the neutral hydrogen (h i) radial brightness temperature profile in large-scale haloes by stacking 48 430 galaxies selected from the 2dfgrs catalogue on to a set of 21-cm intensity maps obtained with the parkes radio telescope, spanning a total area of ∼1300 deg2 on the sky and covering the redshift range 0.0... | the neutral hydrogen distribution in large-scale haloes from 21-cm intensity maps |
we present a detailed multiwavelength follow-up of the nuclear radio flare vt j154843.06+220812.6, hereafter vt j1548. vt j1548 was selected as a ~1 mjy radio flare in 3 ghz observations from the very large array sky survey. it is located in the nucleus of a low-mass ( $\mathrm{log}{m}_{\mathrm{bh}}/{m}_{\odot }\sim 6$... | the nascent milliquasar vt j154843.06+220812.6: tidal disruption event or extreme accretion state change? |
we present the results of atacama large millimeter/submillimeter array (alma) band-5 (∼170 ghz) observations of the merging ultraluminous infrared galaxy, the 'superantennae' (iras 19254-7245), at z = 0.0617, which has been diagnosed as containing a luminous obscured active galactic nucleus (agn). in addition to dense ... | alma detection of millimetre 183 ghz h2o maser emission in the superantennae galaxy at z ∼ 0.06 |
we present the results of multiband observations of the blazar s5 0716+714 intra-night variability performed during 23 nights in the period from 04.2014 through 04.2015. the bluer-when-brighter trend is detected in both intra- and inter-night data. we assume that the jet component crossing the region where the medium b... | a geometrical interpretation for the properties of multiband optical variability of the blazar s5 0716+714 |
we develop a model of the ionospheric electron population of jupiter's moon callisto using a prescribed neutral atmosphere composed of o2, co2 and h2o. a kinetic description of ionospheric suprathermal electrons coupled with a fluid description of ionospheric thermal electrons is well suited to jointly analyze and inte... | structure and density of callisto's atmosphere from a fluid-kinetic model of its ionosphere: comparison with hubble space telescope and galileo observations |
context. infrared dark clouds (irdcs) are ubiquitous in the milky way, yet they play a crucial role in breeding newly-formed stars.aims: with the aim of further understanding the dynamics, chemistry, and evolution of irdcs, we carried out multiwavelength observations on a small sample.methods: we performed new observat... | a multiwavelength observation and investigation of six infrared dark clouds |
the dark ages radio experiment (dare) seeks to study the cosmic dark ages approximately 80 to 420 million years after the big bang. observations require truly quiet radio conditions, shielded from sun and earth electromagnetic (em) emissions, on the far side of the moon. dare's science orbit is a frozen orbit with resp... | dare mission design: low rfi observations from a low-altitude frozen lunar orbit |
ngc 7538 irs 1 is a very young embedded o star driving an ionized jet and accreting mass with an accretion rate >10-4 ${m}_{\odot }$ yr-1, which is quenching the hypercompact h ii region. we use sofia great data, herschel pacs and spire archive data, sofia forcast archive data, onsala 20 m and carma data, and jcmt a... | ngc 7538 irs1—an o star driving an ionized jet and giant n-s outflow |
jets are ubiquitous in the star-forming process since accretion is intimately associated with outflow. weak free-free continuum emission in the centimeter domain is associated with these jets. observations in the cm range are most useful to trace the base of the ionized jets, close to the yso and its accretion disk, wh... | radio jets in young stellar objects with the ska |
radio haloes are extended (∼mpc), steep spectrum sources found in the central region of dynamically disturbed clusters of galaxies. only a handful of radio haloes have been reported to reside in galaxy clusters with a mass $m_{500}\lesssim 5\times 10^{14}\, \mathrm{ m}_\odot$ . in this paper, we present a low frequency... | lofar detection of a low-power radio halo in the galaxy cluster abell 990 |
magnetic reconnection is a fundamental physical process converting magnetic energy into not only plasma energy but also particle energy in various astrophysical phenomena. in this letter, we show a unique data set of a solar flare where various plasmoids were formed by a continually stretched current sheet. extreme ult... | observational signatures of tearing instability in the current sheet of a solar flare |
context. 22 ghz water masers are the most intense and widespread masers in star-forming regions. they are commonly associated with protostellar winds and jets emerging from low- and high-mass young stellar objects (yso).aims: we wish to perform for the first time a statistical study of the location and motion of indivi... | protostellar outflows at the earliest stages (poets). iv. statistical properties of the 22 ghz h2o masers |
the ionosphere is a dynamic layer which generally changes according to radiation emitted by the sun, the movement of the earth around the sun, and sunspot activity. variations can generally be categorized as regular or irregular variations. both types of variation have a huge effect on radio wave propagation. in this s... | comparison between iri-2012 and gps-tec observations over the western black sea |
sausage modes are a leading mechanism for interpreting short-period quasi-periodic pulsations (qpps) of solar flares. forward modeling their radio emission is crucial for identifying sausage modes observationally and for understanding their connections with qpps. using the numerical outputs from three-dimensional magne... | influence of fine structures on gyrosynchrotron emission of flare loops modulated by sausage modes |
we use broadband sensitive lofar observations in the 25-80 mhz frequency range to study the single-pulse emission properties of the mode-switching pulsar b0943+10. we review the derivation of magnetospheric geometry, originally based on low-frequency radio data, and show that the geometry is less strongly constrained t... | psr b0943+10: low-frequency study of subpulse periodicity in the bright mode with lofar |
transitional millisecond pulsars are systems that alternate between an accreting low-mass x-ray binary (lmxb) state and a non-accreting radio pulsar state. when at the lmxb state, their x-ray and optical light curves show rapid flares and dips, the origin of which is not well understood. we present results from our opt... | variable polarisation and doppler tomography of psr j1023+0038 - evidence for the magnetic propeller during flaring? |
we report observations with the atacama large millimetre array (alma) of six submillimetre galaxies (smgs) within 3 arcmin of the distant red core (drc) at z = 4.0, a site of intense cluster-scale star formation, first reported by oteo et al. we find new members of drc in three smg fields; in two fields, the smgs are s... | alma unveils wider environment of distant red protocluster core |
glitches - sudden increases in spin rate - are observed in many pulsars. one mechanism advanced to explain glitches in the youngest pulsars is that they are caused by a starquake, a sudden rearrangement of the crust of the neutron star. starquakes have the potential to excite some of the oscillation modes of the neutro... | developing a model for neutron star oscillations following starquakes |
owing to their quiet evolutionary histories, nearby dwarf galaxies (stellar masses $m_\star \lesssim 3 \times 10^9 \, \mathrm{m}_\odot$) have the potential to teach us about the mechanism(s) that 'seeded' the growth of supermassive black holes, and also how the first stellar mass black holes formed and interacted with ... | multiwavelength scrutiny of x-ray sources in dwarf galaxies: ulxs versus agns |
we present alma images of the dust and molecular line emission in the orion hot core at 349 ghz. at 0.″2 angular resolution the images reveal multiple clumps in an arc ∼1″ east of orion source i, the protostar at the center of the kleinmann-low nebula, and another chain of peaks from irc7 toward the southwest. the mole... | alma images of the orion hot core at 349 ghz |
centimeter continuum emission from protostars offers insight into the innermost part of the outflows, as shock-ionized gas produces free-free emission. we observed a complete population of class 0 and i protostars in the perseus molecular cloud at 4.1 and 6.4 cm with resolution and sensitivity superior to previous surv... | the vla nascent disk and multiplicity survey of perseus protostars (vandam). iii. extended radio emission from protostars in perseus |
we have observed the h ii region rcw175 with the 64 m parkes telescope at 8.4 ghz and 13.5 ghz in total intensity, and at 21.5 ghz in both total intensity and polarization. high angular resolution ranging from 1 to 2.4 arcmin, high sensitivity, and polarization capability enable us to perform a detailed study of the di... | new radio observations of anomalous microwave emission in the h ii region rcw175 |
we studied the sulfur chemistry of massive star-forming regions through single-dish submillimeter spectroscopy. ocs, o13cs, 13cs, h2s, and so transitions were observed toward a sample of massive star-forming regions with embedded uch ii or ch ii regions. these sources could be divided into h ii-hot core and h ii-only s... | sulfur-bearing molecules in massive star-forming regions: observations of ocs, cs, h2s, and so |
we present a multiwavelength study of the sh2-138, a galactic compact h ii region. the data comprise of optical and near-infrared (nir) photometric and spectroscopic observations from the 2-m himalayan chandra telescope, radio observations from the giant metrewave radio telescope (gmrt), and archival data covering radi... | sh2-138: physical environment around a small cluster of massive stars |
we have carried out a multi-epoch simultaneous survey of 22 ghz h2o and 44 ghz class i ch3oh masers toward 103 ultracompact h ii regions (uch iis) between 2010 and 2017. we detected h2o and ch3oh maser emission in 74 (72%) and 55 (53%) uch iis, respectively. among them, three h2o and 27 ch3oh maser sources are new dete... | simultaneous 22 ghz water and 44 ghz methanol maser survey of ultracompact h ii regions |
we have imaged 35 yr of archival very large array observations of the nearby (dl = 3.15 mpc) type ia supernovae sn 1972e and sn 1895b between 9 and 121 yr post-explosion. no radio emission is detected, constraining their radio luminosities to be lν,8.5ghz < 6.0 × 1023 erg s-1 hz-1 45 yr post-explosion and lν,8.5ghz ... | thirty years of radio observations of type ia sn 1972e and sn 1895b: constraints on circumstellar shells |
we have performed a molecular line search towards the flaring 6.7-ghz masers g 24.33+0.13, and g 359.6-0.24 using the australia telescope compact array. we present spectra of the 6.7-ghz class ii methanol and 22.2-ghz water masers towards these sources and provide a comparison with other recent flaring events these sou... | molecular line search towards the flaring 6.7-ghz methanol masers of g 24.33+0.13 and g 359.62-0.24: rare maser transitions detected |
new results on the radio-quiet type 2 quasar, known as the teacup galaxy (sdssj1430+1339), based on the long-slit and 3d spectroscopic data obtained at the russian 6-m telescope, are presented. the ionized gas giant nebula, which extends up to r=56 kpc in the [o iii] emission line, was mapped with the scanning fabry–pe... | gas and stars in the teacup quasar looking with the 6-m telescope |
magnetohydrodynamic (mhd) waves are often invoked to interpret quasiperiodic pulsations (qpps) in solar flares. we study the response of a straight flare loop to a kink-like velocity perturbation using three-dimensional mhd simulations and forward model the microwave emissions using the fast gyrosynchrotron code. kink ... | excitation of multiperiodic kink motions in solar flare loops: possible application to quasiperiodic pulsations |
aims: we seek to study the physical properties of the ionized jet emission in the vicinity of an o-type young stellar object (yso) and to estimate the efficiency of the transfer of energy and momentum from small- to large-scale outflows.methods: we conducted karl g. jansky very large array (vla) observations, at both 2... | momentum-driven outflow emission from an o-type yso. comparing the radio jet with the molecular outflow |
jets of highly energized plasma with relativistic velocities are associated with black holes ranging in mass from a few times that of the sun to the billion-solar-mass black holes at the centres of galaxies. a popular but unconfirmed hypothesis to explain how the plasma is energized is the `internal shock model', in wh... | a kiloparsec-scale internal shock collision in the jet of a nearby radio galaxy |
the planck galactic cold clumps (pgccs) are possible representations of the initial conditions and very early stages of star formation. with the objective of understanding better the star and star cluster formation, we probe the molecular cloud associated with pgcc g108.37-01.06 (hereafter pg108.3), which can be traced... | the planck cold clump g108.37-01.06: a site of complex interplay between h ii regions, young clusters, and filaments |
we report the observational findings of the sh2-112 h ii region by using the multiwavelength data analysis ranging from optical to radio wavelengths. this region is powered by the massive o8v-type star bd +45 3216. the surface density distribution and minimum spanning tree analyses of the young stellar object (yso) can... | star formation and evolution of blister-type h ii region sh2-112 |
quasi-periodic rapidly propagating wave trains are frequently observed in extreme ultraviolet observations of the solar corona, or are inferred by the quasi-periodic modulation of radio emission. the dispersive nature of fast magnetohydrodynamic waves in coronal structures provides a robust mechanism to explain the det... | dispersive evolution of nonlinear fast magnetoacoustic wave trains |
aims: our knowledge of the chemical properties of the circumstellar ejecta of the most massive evolved stars is particularly poor. we aim to study the chemical characteristics of the prototypical yellow hypergiant star, irc +10420. for this purpose, we obtained full line surveys at 1 and 3 mm atmospheric windows.method... | a λ 3 mm and 1 mm line survey toward the yellow hypergiant irc +10420. n-rich chemistry and ir flux variations |
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