Galactic Pulsars Research Articles

Implications for Galactic Electron Density Structure from Pulsar Sightlines Intersecting H ii Regions

Recent radio surveys have revealed pulsars with dispersion and scattering delays induced by ionized gas that are larger than the rest of the observed pulsar population, in some cases with electron column densities (or dispersion measures, DMs) larger than the maximum predictions of Galactic electron density models. By cross-matching the observed pulsar population against H ii region catalogs, we show that the majority of pulsars with DM > 600 pc cm−3 and scattering delays τ(1 GHz) > 10 ms lie behind H ii regions, and that H ii region intersections may be relevant to as much as a third of the observed pulsar population. The fraction of the full pulsar population with sightlines intersecting H ii regions is likely larger. Accounting for H ii regions resolves apparent discrepancies where Galactic electron density models place high-DM pulsars beyond the Galactic disk. By comparing emission measures inferred from recombination line observations to pulsar DMs, we show that H ii regions can contribute tens to hundreds of parsecs per cubic centimeter in electron column density along a pulsar line of sight. We find that nearly all pulsars with significant excess (and deficit) scattering from the mean τ–DM relation are spatially coincident with known discrete ionized gas structures, including H ii regions. Accounting for H ii regions is critical to the interpretation of radio dispersion and scattering measurements as electron density tracers, both in the Milky Way and in other galaxies.

First Detection of X-Ray Polarization in Galactic Ultraluminous X-Ray Pulsar Swift J0243.6+6124 with IXPE

We report the results of first ever spectropolarimetric analyses of the Galactic ultraluminous X-ray pulsar Swift J0243.6+6124 during the 2023 outburst using quasi-simultaneous IXPE, NICER, and NuSTAR observations. A pulsation of period ∼9.79 s is detected in IXPE and NuSTAR observations with pulse fractions (PFs) ∼18% (2–8 keV) and ∼28% (3–78 keV), respectively. Energy-dependent study of the pulse profiles with NuSTAR indicates an increase in PF from ∼27% (3–10 keV) to ∼50% (40–78 keV). Further, epoch-dependent polarimetric measurements during the decay phase of the outburst confirm the detection of significant polarization, with the polarization degree (PD) and polarization angle ranging between ∼2%–3.1% and ∼8.°6–10.°8, respectively, in the 2–8 keV energy range. We also observe that the PD increases up to ∼4.8% at higher energies (≳5 keV) with dominating bbodyrad flux contribution (1.5 ≲ F BB/F PL ≲ 3.4) in the IXPE spectra. The phase-resolved polarimetric study yields PD as ∼1.7%–3.1% suggesting a marginal correlation with the pulse profiles. Moreover, the broadband (0.6–70 keV) energy spectrum of combined NICER and NuSTAR observations is well described by the combination of bbodyrad and cutoffpl components with seed photon temperature (kT bb) ∼0.86 ± 0.03 keV and photon index (Γ) ∼0.98 ± 0.01. With the above findings, we infer that the observed “low” PD in Swift J0243.6+6124 is attributed possibly due to the “vacuum resonance” effect between the overheated and relatively cooler regions of the neutron star boundary layer.

Deceleration of kicked objects due to the Galactic potential

Context. Various stellar objects experience a velocity kick at some point in their evolution. These include neutron stars and black holes at their birth, or binary systems when one of the two components goes supernova. For most of these objects, the magnitude of the kick and its impact on the object dynamics remains a topic of debate. Aims. We investigate how kicks alter the velocity distribution of objects born in the Milky Way disc, both immediately after the kick and at later times, and whether these kicks are encoded in the observed population of Galactic neutron stars. Methods. We simulated the Galactic trajectories of point masses on circular orbits in the disc after being perturbed by an isotropic kick, with a Maxwellian distribution where σ = 265 km s−1. Then, we simulated the motion of these point masses for 200 Myr. These trajectories were then evaluated, either for the Milky Way population as a whole or for those passing within two kiloparsecs of the Sun, to get the time evolution of the velocities. Results. During the first 20 Myr, the bulk velocity of kicked objects becomes temporarily aligned with the cylindrical radius, implying an anisotropy in the velocity orientations. Beyond this age, the velocity distribution shifts towards lower values and settles to a median of ∼200 km s−1. Around the Sun, the distribution also loses its upper tail, primarily due to unbound objects escaping the Galaxy. We compared this to the velocities of Galactic pulsars and find that pulsars show a similar evolution with characteristic age. Conclusions. The shift in the velocity distribution is due to bound objects spending most of their orbits at larger radii after the kick. They are, therefore, decelerated by the Galactic potential. We find the same deceleration for nearby objects and the total population, and conclude that it is also observed in Galactic pulsars. Because of this effect, the (scalar) speeds of old neutron stars provide little information about their kicks at birth.

The Curious Case of Twin Fast Radio Bursts: Evidence for Neutron Star Origin?

Fast radio bursts (FRBs) are brilliant short-duration flashes of radio emission originating at cosmological distances. The vast diversity in the properties of currently known FRBs and the fleeting nature of these events make it difficult to understand their progenitors and emission mechanism(s). Here we report high time resolution polarization properties of FRB 20210912A, a highly energetic event detected by the Australian Square Kilometre Array Pathfinder (ASKAP) in the Commensal Real-time ASKAP Fast Transients survey, which show intraburst position angle (PA) variation similar to Galactic pulsars and unusual variation of Faraday rotation measure (RM) across its two sub-bursts. The observed intraburst PA variation and apparent RM variation pattern in FRB 20210912A may be explained by a rapidly spinning neutron star origin, with rest-frame spin periods of ∼1.1 ms. This rotation timescale is comparable to the shortest known rotation period of a pulsar and close to the shortest possible rotation period of a neutron star. Curiously, FRB 20210912A exhibits a remarkable resemblance to the previously reported FRB 20181112A, including similar rest-frame emission timescales and polarization profiles. These observations suggest that these two FRBs may have similar origins.

Isolated Pulsar Population Synthesis with Simulation-based Inference

We combine pulsar population synthesis with simulation-based inference (SBI) to constrain the magnetorotational properties of isolated Galactic radio pulsars. We first develop a framework to model neutron star birth properties and their dynamical and magnetorotational evolution. We specifically sample initial magnetic field strengths, B, and spin periods, P, from lognormal distributions and capture the late-time magnetic field decay with a power law. Each lognormal is described by a mean, μlogB,μlogP , and standard deviation, σlogB,σlogP , while the power law is characterized by the index, a late. We subsequently model the stars’ radio emission and observational biases to mimic detections with three radio surveys, and we produce a large database of synthetic P– Ṗ diagrams by varying our five magnetorotational input parameters. We then follow an SBI approach that focuses on neural posterior estimation and train deep neural networks to infer the parameters’ posterior distributions. After successfully validating these individual neural density estimators on simulated data, we use an ensemble of networks to infer the posterior distributions for the observed pulsar population. We obtain μlogB=13.10−0.10+0.08 , σlogB=0.45−0.05+0.05 and μlogP=−1.00−0.21+0.26 , σlogP=0.38−0.18+0.33 for the lognormal distributions and alate=−1.80−0.61+0.65 for the power law at the 95% credible interval. We contrast our results with previous studies and highlight uncertainties of the inferred a late value. Our approach represents a crucial step toward robust statistical inference for complex population synthesis frameworks and forms the basis for future multiwavelength analyses of Galactic pulsars.

Anatomy of astrophysical echoes from axion dark matter

If the dark matter in the Universe is made of μeV axion-like particles (ALPs), then a rich phenomenology can emerge in connection to their stimulated decay into two photons. We discuss the ALP stimulated decay induced by electromagnetic radiation from Galactic radio sources. Three signatures, made by two echoes and one collinear emission, are associated with the decay, and can be simultaneously detected, offering a unique opportunity for a clear ALP identification. We derive the formalism associated with such signatures starting from first principles, and providing the relevant equations to be applied to study the ALP phenomenology.We then focus on the case of Galactic pulsars as stimulating sources and derive forecasts for future observations, which will be complementary to helioscopes and haloscopes results.

The FAST Galactic Plane Pulsar Snapshot Survey – V. PSR J1901+0658 in a double neutron star system

ABSTRACT Double neutron star (DNS) systems offer excellent opportunities to test gravity theories. We report the timing results of PSR J1901+0658, the first pulsar discovered in the FAST Galactic Plane Pulsar Snapshot (GPPS) Survey. Based on timing observations by FAST over 5 yr, we obtain the phase-coherent timing solution and derive the precise measurements of its position, spin parameters, orbital parameters, and dispersion measure. It has a period of 75.7 ms, a period derivative of 2.169(6) × 10−19 s s−1, and a characteristic age of 5.5 Gyr. This pulsar is in an orbit with a period of 14.45 d and an eccentricity of 0.366. One post-Keplerian parameter, periastron advance, has been well-measured as being 0.00531(9) deg yr−1, from which the total mass of this system is derived to be 2.79(7) M⊙. The pulsar has the mass upper limit of 1.68 M⊙, so the lower limit for the companion mass is 1.11 M⊙. Because PSR J1901+0658 is a partially recycled pulsar in an eccentric binary orbit with such a large companion mass, it should be in a DNS system according to the evolution history of the binary system.

Deep Synoptic Array Science: Polarimetry of 25 New Fast Radio Bursts Provides Insights into Their Origins

We report on a full-polarization analysis of the first 25 as yet nonrepeating fast radio bursts (FRBs) detected at 1.4 GHz by the 110-antenna Deep Synoptic Array (DSA-110) during commissioning observations. We present details of the data-reduction, calibration, and analysis procedures developed for this novel instrument. Faraday rotation measures (RMs) are searched between ±106 rad m−2 and detected for 20 FRBs, with magnitudes ranging from 4 to 4670 rad m−2. Fifteen out of 25 FRBs are consistent with 100% polarization, 10 of which have high (≥70%) linear-polarization fractions and two of which have high (≥30%) circular-polarization fractions. Our results disfavor multipath RM scattering as a dominant depolarization mechanism. Polarization-state and possible RM variations are observed in the four FRBs with multiple subcomponents. We combine the DSA-110 sample with polarimetry of previously published FRBs, and compare the polarization properties of FRB subpopulations and FRBs with Galactic pulsars. Although FRB polarization fractions are typically higher than those of Galactic pulsars, and cover a wider range than those of pulsar single pulses, they resemble those of the youngest (characteristic ages <105 yr) pulsars. Our results support a scenario wherein FRB emission is intrinsically highly linearly polarized, and propagation effects can result in conversion to circular polarization and depolarization. Young pulsar emission and magnetospheric propagation geometries may form a useful analogy for the origin of FRB polarization.

Overlap reduction function for pulsar timing arrays in an expanding Universe

Since it was confirmed two decades ago that the expansion of the Universe is accelerating, it would be of theoretical interests to figure out what is the influence from cosmological constant on detection of stochastic gravitational wave background. This paper studies the overlap reduction functions in de-Sitter space-time for a pair of one-way tracking gravitational wave detectors. It is shown to be non-trivial in an expanding Universe, because the propagation of light along line of sight also has effect on the response of GW detectors. It is found that the expansion of the Universe can enhance the value of magnitude of the overlap reduction functions, when the detector pairs are close to each other. For nanohertz gravitational waves, this effect can dominate the values of overlap reduction functions when the galactic pulsar pairs are separated by milliarcsecond.

Deep Synoptic Array Science: Implications of Faraday Rotation Measures of Fast Radio Bursts Localized to Host Galaxies

Faraday rotation measures (RMs) of fast radio bursts (FRBs) offer the prospect of directly measuring extragalactic magnetic fields. We present an analysis of the RMs of 10 as yet nonrepeating FRBs detected and localized to host galaxies with robust redshift measurements by the 63-antenna prototype of the Deep Synoptic Array (DSA-110). We combine this sample with published RMs of 15 localized FRBs, nine of which are repeating sources. For each FRB in the combined sample, we estimate the host-galaxy dispersion measure (DM) contributions and extragalactic RM. We find compelling evidence that the extragalactic components of FRB RMs are often dominated by contributions from the host-galaxy interstellar medium (ISM). Specifically, we find that both repeating and as yet nonrepeating FRBs show a correlation between the host DM and host RM in the rest frame, and we find an anticorrelation between extragalactic RM (in the observer frame) and redshift for nonrepeaters, as expected if the magnetized plasma is in the host galaxy. Important exceptions to the ISM origin include a dense, magnetized circumburst medium in some repeating FRBs, and the intracluster medium of host or intervening galaxy clusters. We find that the estimated ISM magnetic-field strengths, , are characteristically ∼1–2 μG larger than those inferred from Galactic radio pulsars. This suggests either increased ISM magnetization in FRB hosts in comparison with the Milky Way, or that FRBs preferentially reside in regions of increased magnetic-field strength within their hosts.

The FAST Galactic Plane Pulsar Snapshot Survey – III. Timing results of 30 newly discovered pulsars

ABSTRACT Timing observations are crucial for determining the basic parameters of newly discovered pulsars. Using the Five-hundred-meter Aperture Spherical radio Telescope (FAST) with the L-band 19-beam receiver covering the frequency range of 1.0–1.5 GHz, the FAST Galactic Plane Pulsar Snapshot (GPPS) Survey has discovered more than 600 faint pulsars with flux densities of only a few or a few tens of μJy at 1.25 GHz. To obtain accurate position, spin parameters and dispersion measure of a pulsar, and to calculate derived parameters such as the characteristic age and surface magnetic field, we collect available FAST pulsar data obtained either through targeted follow-up observations or through coincidental survey observations with one of the 19 beams of the receiver. From these data we obtain time of arrival (TOA) measurements for 30 newly discovered pulsars as well as for 13 known pulsars. We demonstrate that the TOA measurements acquired by the FAST from any beams of the receiver in any observation mode (e.g. the tracking mode or the snapshot mode) can be combined to get timing solutions. We update the ephemerides of 13 previously known pulsars and obtain the first phase-coherent timing results for 30 isolated pulsars discovered in the FAST GPPS Survey. Notably, PSR J1904+0853 is an isolated millisecond pulsar, PSR J1906+0757 is a disrupted recycled pulsar, and PSR J1856+0211 has a long period of 9.89 s that can constrain pulsar death lines. Based on these timing solutions, all available FAST data have been added together to obtain the best pulse profiles for these pulsars.

Quasi-regular variations of subpulse drifting for PSR J1857+0057

ABSTRACT During observations of the Galactic Plane Pulsar Snapshot survey by the Five-hundred-meter Aperture Spherical radio Telescope, varying subpulse drifting of PSR J1857+0057 is detected. The follow-up observation confirms the quasi-regular changes of the drifting rate about every 50 periods. We determine the drift rate D through a linear fit to the pulse-central longitudes of subpulses in a drifting band, and determine P3 from the cross-points of two fitted lines at the zero longitude for two neighbouring drifting bands. The low frequency modulation of about every 50 periods is found on variations of not only pulse intensity but also drift parameters. In most of low frequency modulation cycles, the integrated pulse intensity I and the absolute drift rate |D| tend to increase first and then decrease, and the drifting periodicity P3 varies just in the opposite. In addition, the phase-forward intensity-enhancement is observed in many modulation cycles. Based on our polarization data, the average position angle curve for pulses with a smaller |D| and larger P3 is slightly steep in the leading edge of pulse profile compared with that of the fully averaged profile.

The FAST Galactic Plane Pulsar Snapshot Survey. II. Discovery of 76 Galactic Rotating Radio Transients and the Enigma of RRATs

We have carried out the Galactic Plane Pulsar Snapshot (GPPS) survey by using the Five-hundred-meter Aperture Spherical radio Telescope (FAST), the most sensitive systematic pulsar survey in the Galactic plane. In addition to more than 500 pulsars already discovered through normal periodical search, we report here the discovery of 76 new transient radio sources with sporadic strong pulses, detected by using the newly developed module for a sensitive single-pulse search. Their small DM values suggest that they all are Galactic rotating radio transients (RRATs). They show different properties in the follow-up observations. More radio pulses have been detected from 26 transient radio sources but no periods can be found due to a limited small number of pulses from all FAST observations. The follow-up observations show that 16 transient sources are newly identified as being the prototypes of RRATs with a period already determined from more detected sporadic pulses, and 10 sources are extremely nulling pulsars, and 24 sources are weak pulsars with sparse strong pulses. On the other hand, 48 previously known RRATs have been detected by the FAST, either during verification observations for the GPPS survey or through targeted observations of applied normal FAST projects. Except for one RRAT with four pulses detected in a session of 5-minute observation and four RRATs with only one pulse detected in a session, sensitive FAST observations reveal that 43 RRATs are just generally weak pulsars with sporadic strong pulses or simply very nulling pulsars, so that the previously known RRATs always have an extreme emission state together with a normal hardly detectable weak emission state. This is echoed by the two normal pulsars J1938+2213 and J1946+1449 with occasional brightening pulses. Though strong pulses of RRATs are very outstanding in the energy distribution, their polarization angle variations follow the polarization angle curve of the averaged normal pulse profile, suggesting that the predominant sparse pulses of RRATs are emitted in the same region with the same geometry as normal weak pulsars.

FAST Pulsar Database. I. Polarization Profiles of 682 Pulsars

Pulsar polarization profiles form a very basic database for understanding the emission processes in a pulsar magnetosphere. After careful polarization calibration of the 19-beam L-band receiver and verification of beam-offset observation results, we obtain polarization profiles of 682 pulsars from observations by the Five-hundred-meter Aperture Spherical radio Telescope (FAST) during the Galactic Plane Pulsar Snapshot survey and other normal FAST projects. Among them, polarization profiles of about 460 pulsars are observed for the first time. The profiles exhibit diverse features. Some pulsars have a polarization position angle curve with a good S-shaped swing, some with orthogonal modes; some have components with highly linearly polarized components or strong circularly polarized components; some have a very wide profile, coming from an aligned rotator, and some have an interpulse from a perpendicular rotator; some wide profiles are caused by interstellar scattering. We derive geometric parameters for 190 pulsars from the S-shaped position angle curves or with orthogonal modes. We find that the linear and circular polarization or the widths of pulse profiles have various frequency dependencies. Pulsars with a large fraction of linear polarization are more likely to have a large Edot.

The FAST Galactic Plane Pulsar Snapshot survey – IV. Discovery of five fast radio bursts

ABSTRACT We report five new fast radio bursts (FRBs) discovered from the Galactic Plane Pulsar Snapshot (GPPS) survey by the Five-hundred-meter Aperture Spherical radio Telescope (FAST): FRB 20210126, FRB 20210208, FRB 20210705, FRB 20211005, and FRB 20220306. To date, no repeating bursts from these FRB sources have been detected in the follow-up monitoring observations, leading to their classification as potential one-off events. We obtain the basic parameters for these bursts, including position, dispersion measure, pulse width, spectral index, scattering time-scale, etc. The fluences and flux densities are generally lower in comparison to the values observed in one-off bursts discovered by other telescopes. Among the observed bursts, polarization data for four bursts were recorded during observations. Consequently, we obtain polarization profiles and Faraday rotation measures for these bursts.

Flux Calibration of CHIME/FRB Intensity Data

Fast radio bursts (FRBs) are bright radio transients of microsecond to millisecond duration and unknown extragalactic origin. Central to the mystery of FRBs are their extremely high characteristic energies, which surpass the typical energies of other radio transients of similar duration, like Galactic pulsar and magnetar bursts, by orders of magnitude. Calibration of FRB-detecting telescopes for burst flux and fluence determination is crucial for FRB science, as these measurements enable studies of the FRB energy and brightness distribution in comparison to progenitor theories. The Canadian Hydrogen Intensity Mapping Experiment (CHIME) is a radio interferometer of cylindrical design. This design leads to a high FRB detection rate but also leads to challenges for CHIME/FRB flux calibration. This paper presents a comprehensive review of these challenges, as well as the automated flux calibration software pipeline that was developed to calibrate bursts detected in the first CHIME/FRB catalog, consisting of 536 events detected between 2018 July 25 and 2019 July 1. We emphasize that, due to limitations in the localization of CHIME/FRB bursts, flux and fluence measurements produced by this pipeline are best interpreted as lower limits, with uncertainties on the limiting value.

H i Galaxy Detections in the Zone of Avoidance with FAST

The Zone of Avoidance (ZoA) is a region of low galactic latitude that is heavily obscured by the Milky Way. Observations with radio telescopes are basically unaffected by dust extinction and can unveil the structure behind it through the Milky Way. One of the scientific goals of the Five-hundred-meter Aperture Spherical radio Telescope (FAST) is to search for the neutral hydrogen and understand the large-scale physics to explore the origin and evolution of the universe. We take the 15,500 IRAS (the Infrared Astronomical Satellite) galaxies from PSCz (“Point Source Catalog”) survey to reconstruct the density field of the local universe, obtain the distribution of the relative density of galaxies in the ZoA region with a redshift z below 0.07, and the number of detectable galaxies with FAST is estimated by using the neutral hydrogen mass function of the ALFA (Arecibo L-band Feed Array) survey. We conclude that FAST can observe more than 2000 ZoA galaxies within a distance of 300 Mpc , and present preliminary results of the partial GPPS (the FAST Galactic Plane Pulsar Snapshot survey) data, compared with ALFA ZoA (The Arecibo L-band Feed Array Zone of Avoidance), show that FAST has a higher detection sensitivity to search for H i galaxies in the ZoA area.

The Spin-down Accretion Regime of Galactic Ultraluminous X-Ray Pulsar Swift J0243.6+6124

The relatively high fluxes of the Galactic ultraluminous X-ray pulsar Swift J0243 allow a detailed study of its spin-down regime in the quiescent state for the first time. After the 2017 giant outburst, its spin frequency shows a linearly decreasing trend with some variations due to minor outbursts. The linear spin-down rate is ∼ −1.9 × 10−12 Hz s−1 during the period of lowest luminosity, from which one can infer a dipole field of ∼1.75 × 1013 G. The relation during the spin-down regime is complex, and is close to zero when the luminosity reaches both the high end (L 38 ∼ 0.3) and the lowest value (L 38 ∼ 0.03). The luminosity of zero torque is different for the giant outburst and other minor outbursts. This is likely due to different accretion flows for different types of outburst, as evidenced by the differences in the spectra and pulse profiles at a similar luminosity for different types of outburst (giant or not). The pulse profile changes from double peaks in the spin-up state to a single broad peak in the low spin-down regime, indicating the emission beam/region is larger in the low spin-down regime. These results show that accretion is still ongoing in the low spin-down regime, for which the neutron star is supposed to be in a propeller state.

Probing ensemble properties of vortex-avalanche pulsar glitches with a stochastic gravitational-wave background search

A stochastic gravitational-wave background (SGWB) is expected to be produced by the superposition of individually undetectable, unresolved gravitational-wave (GW) signals from cosmological and astrophysical sources. Such a signal can be searched with dedicated techniques using the data acquired by a network of ground-based GW detectors. In this work, we consider the astrophysical SGWB resulting from pulsar glitches, which are sudden increases in the rotational pulsar frequency, within our Galaxy. More specifically, we assume glitches to be associated with quantized, superfluid, vortex avalanches in the pulsars, and we model the SGWB from the superposition of GW bursts emitted during the glitching phase. We perform a cross-correlation search for this SGWB-like signal employing the data from the first three observation runs of Advanced LIGO and Virgo. Not having found any evidence for a SGWB signal, we set upper limits on the dimensionless energy density parameter ${\mathrm{\ensuremath{\Omega}}}_{\mathrm{gw}}(f)$ for two different power-law SGWBs, corresponding to two different glitch regimes. We obtain ${\mathrm{\ensuremath{\Omega}}}_{\mathrm{gw}}(f)\ensuremath{\le}7.5\ifmmode\times\else\texttimes\fi{}{10}^{\ensuremath{-}10}$ at 25 Hz for a spectral index $5/2$, and ${\mathrm{\ensuremath{\Omega}}}_{\mathrm{gw}}(f)\ensuremath{\le}5.7\ifmmode\times\else\texttimes\fi{}{10}^{\ensuremath{-}17}$ at 25 Hz for a spectral index $17/2$. We then use these results to set constraints on the average glitch duration and the average radial motion of the vortices during the glitches for the population of the glitching Galactic pulsars, as a function of the Galactic glitch rate.

Multiclass classification of Fermi-LAT sources with hierarchical class definition

ABSTRACT In this paper, we develop multiclass classification of Fermi-large area telescope (LAT) gamma-ray sources using machine learning with hierarchical determination of classes. One of the main challenges in the multiclass classification of the Fermi-LAT sources is that the size of some of the classes is relatively small, for example with less than 10 associated sources belonging to a class. In this paper, we propose a hierarchical structure for the determination of the classes. This enables us to have control over the size of classes and to compare the performance of the classification for different numbers of classes. In particular, the class probabilities in the two-class case can be computed either directly by the two-class classification or by summing probabilities of children classes in multiclass classification. We find that the classifications with few large classes have comparable performance with classifications with many smaller classes. Thus, on one hand, the few-class classification can be recovered by summing probabilities of classification with more classes while, on the other hand, the classification with many classes gives a more detailed information about the physical nature of the sources. As a result of this work, we construct three probabilistic catalogues, which are available online. This work opens up a possibility to perform population studies of sources including unassociated sources and to narrow down searches for possible counterparts of unassociated sources, such as active galactic nuclei, pulsars, or millisecond pulsars.