Ru-Shuang Zhao

We present a catalog of 5595 giant radio source (GRS) candidates, defined by a largest (projected) linear size (LLS) exceeding 0.7 Mpc. Of these, 4566 would be new discoveries if confirmed. These candidates were identified through a systematic and automated search of the first Alternative Data Release of the TIFR GMRT Sky Survey (TGSS ADR1) using a deep learning–based pipeline that incorporates a radio source detection model and the likelihood ratio method. Across the full sample, the LLS reaches up to ∼4.5 Mpc, with redshifts ranging from z = 0.056 to at least z = 2.385. The catalog comprises 4210 giant radio galaxies and 1030 giant radio quasars, with the remaining 355 candidates currently unclassified. We systematically analyze the distributions of their key physical properties, including spectral index, bending angle (BA), radio power ( P ₁₅₀ ), and r -band absolute magnitude. Our results show that GRS candidates are predominantly straight (a median BA of 11 . ° 0) and follow an “L-shaped” BA–LLS distribution. The radio power versus LLS ( P ₁₅₀ – D ) diagram reveals a concentration at P ₁₅₀ < 10 ²⁸ W Hz ⁻¹ , while rare high-power outliers (>10 ^28.5 W Hz ⁻¹ ) with LLS > 1 Mpc challenge self-similar evolutionary models. Additionally, 286 GRS candidates are found to be associated with cataloged galaxy clusters.

Fast radio bursts (FRBs) are millisecond-duration extragalactic radio transients, some of which are associated with compact persistent radio sources (PRSs), hinting at a physical connection. While several models have been proposed to explain PRSs and their connection to FRBs, direct observational tests remain limited. Here, we report for the first time a correlated trend between the long-term variation of the PRS flux density and the burst energetics of FRB 20190520B and FRB 20240114A, suggesting a physical coupling between the PRS and FRB activity. We further examine additional repeaters with compact PRSs and find no clear correlation between PRS luminosity and burst activity, likely due to the limited observations. These results are consistent with scenarios in which both the PRS and FRB activity may be powered by a common energy reservoir, such as the magnetic or rotational energy of a magnetar.

Polarization measurements of fast radio bursts (FRBs) probe the magnetized plasma surrounding their central engines. FRB 20240114A is an exceptionally active repeating source, with 17,356 bursts detected between 2024 January 28 and 2025 May 30 by FAST, enabling studies of the temporal evolution of its polarization properties. In this work, we present a polarimetric catalog of 6131 bright bursts (with a signal-to-noise ratio (S/N) ≥ 20, 35.3% of the total sample), including arrival time (MJD _topo ), dispersion measure (DM), burst width ( W _eff ), bandwidth, Faraday rotation measure (RM), linear and circular polarization degrees ( L / I , V / I ), and intrinsic polarization angle (PA ₀ ). We confirm a clear temporal evolution of RM: after an initial stable phase, it decreases linearly by ∼200 rad m ⁻² over 200 days, forming a bimodal distribution, whereas DM remains stable at 529.3 ± 1.2 pc cm ⁻³ . The linear polarization fraction is generally high, with the 3 σ lower bound around 76%, while circular polarization is low, with 1157 of 17,356 bursts (6.67%) having ∣ V ∣/ I ≥ 10%. We perform a power-law fit between ∣ V ∣/ I and ∣RM∣, which yields an index of −2.98 ± 0.80. It is found that the combined 2D distribution of L / I versus V / I remains stable, implying that the emission mechanism is largely invariant. Our PA ₀ measurements show a broad, nonuniform distribution, implying a complex emission geometry. These results suggest that FRB 20240114A resides in a dynamically evolving magneto-ionic environment. This catalog provides a foundation for studies of repeating FRB progenitors and their environments.

We present phase-connected timing solutions, total-intensity and polarized profiles for two newly discovered pulsars, PSRs J1929+4105 and J2359+4239, identified by the Five-hundred-meter Aperture Spherical radio Telescope (FAST) in the Commensal Radio Astronomy FAST Survey (or CRAFTS). PSR J1929+4105 has a spin period of 41.59 ms and is in a 63 days orbit with an eccentricity of 0.00042. PSR J2359+4239, with a spin period of 60.53 ms, is in a 4 days orbit with an eccentricity of 0.0003. Since no post-Keplerian parameters have been measured for either system, we can only constrain the companion masses based on the mass function. The minimum companion masses for PSRs J1929+4105 and J2359+4239 are 0.72 M _⊙ and 0.467 M _⊙ , respectively. Given the small eccentricities of these systems, which rule out the possibility of double neutron star systems, we propose that both systems consist of a pulsar and a massive white dwarf companion. Simulations of the formation processes for these two systems were conducted using the rapid binary population synthesis code COMPAS. We estimated their distances using the NE2001 and YMW16 electron-density models, thereby contributing new data to the Galactic electron-density distribution. Motivated by the numerous discoveries of millisecond pulsar binaries by FAST, we further studied their height distribution in the Galaxy.

We present a systematic study of giant pulses (GPs) from the Crab pulsar (PSR J0534+2200) using ultra-wideband observations with the Parkes radio telescope. We introduce an empirical classification scheme based on the cumulative distribution function (CDF) of pulse energy in frequency, separating the detected events into narrow-band and broadband GPs, with the former dominating the present sample. The narrow-band events concentrate most of their energy within limited frequency ranges, whereas broadband events show more extended spectral coverage. Spectral fitting shows that most narrow-band GPs have negative spectral indices, while a few events exhibit positive slopes, indicating substantial spectral diversity within the sample. The 3σ widths of narrow-band main pulse GPs appear to cluster around two characteristic ranges, although this feature should be interpreted with caution given the time resolution of the data. The energy distribution of narrow-band main pulse GPs is broadly consistent with a log-normal form at low-to-intermediate energies and a power-law-like tail at the high-energy end. The waiting-time distribution can be described by a Weibull function, while a sliding-window comparison with Monte Carlo Poisson realizations shows no statistically significant deviation from temporal independence over the present 18.9-minute observing span. These results provide observational constraints on the phenomenology of Crab giant pulses and may be useful for future studies of pulsar coherent emission and related radio transients.

We present a catalog of 971 FR I radio galaxies (FR Is) identified from the Very Large Array Faint Images of the Radio Sky at Twenty centimeters (FIRST) survey. The identifications were made using a hybrid method that combines deep learning with ridgeline flux density distribution analysis. Among these sources, 845 are new discoveries. The catalog comprises sources characterized by edge-darkened double jets, an absence of significant bent morphology, and angular sizes ranging from 23″ to 159″. Optical and/or infrared counterparts have been identified for 813 FR Is. Among these, the host galaxies are predominantly (88.1%) red galaxies, with the remainder (11.9%) being blue galaxies; notably, most blue galaxies exhibit high radio power. The FR I sample spans a radio power range of 1.20 × 10 ²¹ ≤ P ₁₄₀₀ ≤ 3.55 × 10 ²⁷ W Hz ⁻¹ at 1400 MHz and reaches redshifts up to z = 2.307. The host galaxies have r -band absolute magnitudes in the range of −24 ≲ M _r ≲ −20 mag. For the 512 FR Is with estimates, the black hole masses fall within 10 ⁷ ≲ M _BH ≲ 7.94 × 10 ⁹ M _⊙ . Based on optical emission-line ratios and mid-infrared colors, spectroscopic classification shows that 571 hosts are low-excitation radio galaxies and 59 are high-excitation radio galaxies.