The follow-up timing observations were carried out for 24 pulsars discovered with the Five-hundred-meter Aperture Spherical radio Telescope (FAST) in Commensal Radio Astronomy FAST Survey (CRAFTS). We report their phase-connected timing ephemeris, polarization pulse profiles and Faraday rotation measurements. With their spin periods spanning from 2.995 ms to 4.34 s, their period derivative were determined to spread between 7.996(8) × 10⁻²¹ s/s and 9.83(3) × 10⁻¹⁵ s/s, which imply that they have characteristic ages from 1.97 × 10⁶ yr to 5.93 × 10⁹ yr. It is inferred that PSRs J0211+4235 and J0518+2431 are beyond the ‘traditional death line’. PSR J0211+4235 is beyond the ‘death valley’. The death line model of Zhang et al (2000) also cannot explain the radio presence of PSR J0211+4235. This suggests that radiation theory needs to be improved. Besides, ten of the 22 canonical pulsars show nulling phenomena. Moreover, PSR J1617+1123 exhibits variation of emission and J0540+4542 shows subpulse drifting. The DM of five pulsars is larger than the estimated by the YMW16 electron density model, which could suggest that electron density models need updates for higher Galactic latitude regions. PSRs J0447+2447 and J1928−0548 are isolated millisecond pulsars. With their flux densities spanning from 5(1) μJy – 553(106) μJy, some of these new pulsars found by FAST are distant, dim, and low-|$\dot{E}$| ones and are suitable for testing pulsar emission theories.

The study of polarization and micro-structure is very important for understanding the radiation mechanism of Rotating Radio Transients (RRATs). Due to the limitations of telescope sensitivity and time resolution, studies of the polarization and micro-structure of RRATs have been rare in the past. In this work, we report on a high-time resolution and full polarization observation of RRAT J0139+3336 with the Five-hundred-meter Aperture Spherical Radio Telescope (FAST). A total of 96 burst pulses were detected in the 3-h observation. The degrees of linear and circular polarization and the shape of the polarization position angle (PPA) of the single pulses vary significantly. The average profile displays a small degree of linear and circular polarization, and the PPA exhibits a remarkably smooth and steep S-shaped curve, which are also characteristics of pulsars. The circular polarization in some single pulses demonstrates a clear sign change. We discuss the geometric structure of the emission beam based on the results from fitting the RVM model to the changes in the PPA. Using an autocorrelation analysis, the quasi-periodic micro-structure in the single pulse emission is detected with a median period of about 0.91 ms. We show that the position of RRAT J0139+3336 on the P–P_μ diagram falls in the normal pulsar (NP) region . The radio emission of RRAT J0139+3336 shows unique properties, such as the sign change in the circular polarization and quasi-periodicity in the micro-structure, which will provide important clues to the emission mechanism of RRATs.

Bent-tail radio galaxies (BTRGs) are characterized by bent radio lobes. This unique shape is mainly caused by the movement of the galaxy within a cluster, during which the radio jets are deflected by the intracluster medium. A combined method, which involves a deep learning-based radio source finder along with visual inspection, has been utilized to search for BTRGs from the Faint Images of the Radio Sky at Twenty cm survey images. Consequently, a catalog of 4876 BTRGs has been constructed, among which 3871 are newly discovered. Based on the classification scheme of the opening angle between the two jets of the galaxy, BTRGs are typically classified as either wide-angle-tail (WAT) sources or narrow-angle-tail (NAT) sources. Our catalog comprises 4424 WATs and 652 NATs. Among these, optical counterparts are identified for 4193 BTRGs. This catalog covers luminosities in the range of 1.91 × 10²⁰ ≤ L _{1.4 GHz} ≤ 1.45 × 10²⁸ W Hz⁻¹ and redshifts from z = 0.0023 to z = 3.43. Various physical properties of these BTRGs and their statistics are presented. Particularly, by the nearest neighbor method, we found that 1825 BTRGs in this catalog belong to galaxy clusters reported in literature.

We report a high-resolution study of the radio radiation properties of RRAT J1913 + 1330 based on data obtained from three observing epochs over 4 months using the Five-hundred-meter Aperture Spherical Radio telescope (FAST). Segments of bursts and nulls are detected from the RRAT, which are in agreement with earlier results. From our observations, we identify nine burst segments, and the pulse profile is different for burst segments. We obtain polarization profile for the RRAT J1913 + 1330, and study the polarization, energy distribution, and the wait time distribution between pulses for different burst states. The results show that there are significant differences in the polarization profiles and linear polarization position angle (PA) across different burst states. In addition, pulses in the burst states are discontinuous, and there is no short-term correlation of the arrival time of single pulses in our observations. More interestingly, we find that the PA from some single pulses with high linear polarization demonstrates very different characteristics. The unique radiation characteristics of RRAT J1913 + 1330 will provide important clues for studying its radiation mechanism.

PSR B0820 + 02 is known to exhibit the subpulse drifting phenomenon, which carries vital information about the pulsar radiation process. In this work, we studied the subpulse drifting of PSR B0820 + 02 at a central frequency of 1250 MHz using the Five-hundred-meter Aperture Spherical radio Telescope (FAST). Thanks to the superior sensitivity of FAST, we found that PSR B0820 + 02 shows four distinct subpulse drifting modes (A, B, C, and D), the last three of which have not been reported before. The drifting periodicities of these four modes are found to be 4.3P₁, 6.4P₁, 8.2P₁, and 10.3P₁ (P₁ is the pulse period), respectively. No null pulse is found in our FAST observation. By comparing the energy distribution of single pulses of all four modes, we found that mode A has the highest energy and mode D has the lowest energy. Finally, we interpreted the drift modes in terms of the carousel model, and showed that if B0820 + 02’s different drift modes are due to aliasing effects, the carousel rotation period of P₄ lies in the range 29P₁–33P₁. The new subpulse drifting phenomena of PSR B0820 + 02 reported here provide a unique opportunity for understanding the mechanism and radiation geometry of pulsar radio radiation.

We discover three new weak pulse components in two known pulsars, one in PSR J0304+1932 and two in PSR J1518+4904. These components are emitted about halfway between the main emission beam and the interpulse beam (beam from the opposite pole). They are separated from their main pulse peak by 99° ± 3° for J0304+1932 and 123.°6 ± 0.°7 (leading) and 93° ± 0.°4 (trailing) for J1518+4904. Their peak-intensity ratios to main pulses are ∼ 0.06% for J0304+1932 and ∼0.17% and ∼0.83% for J1518+4904. We also analyzed the flux fluctuations and profile variations of the emissions for the two pulsars. The results show correlations between the weak pulses and their main pulses, indicating that these emissions come from the same pole. We estimated the emission altitude of these weak pulses and derived a height of about half of the pulsar’s light-cylinder radius. These pulse components are a unique sample of high-altitude emissions from pulsars, and challenge the current pulsar emission models.