A pulsar's scintillation bandwidth is inversely proportional to the scattering delay, making accurate measurements of scintillation bandwidth critical to characterize unmitigated delays in efforts to measure low-frequency gravitational waves with pulsar timing arrays. In this pilot work, we searched for a subset of known pulsars within ∼97% of the data taken with the Puerto Rico Ultimate Pulsar Processing Instrument for the AO327 survey with the Arecibo telescope, attempting to measure the scintillation bandwidths in the data set by fitting to the 2D autocorrelation function of their dynamic spectra. We successfully measured 38 bandwidths from 23 pulsars (six without prior literature values), finding that: almost all of the measurements are larger than the predictions from NE2001 and YMW16 (two popular galactic models); NE2001 is more consistent with our measurements than YMW16; Gaussian fits to the bandwidth are more consistent with both electron density models than Lorentzian ones; and for the 17 pulsars with prior literature values, the measurements between various sources often vary by a few factors. The success of Gaussian fits may be due to the use of Gaussian fits to train models in previous work. The variance of literature values over time could relate to the scaling factor used to compare measurements, but also seems consistent with time-varying interstellar medium parameters. This work can be extended to the rest of AO327 to further investigate these trends, highlighting the continuing importance of large archival data sets for projects beyond their initial conception.
Nulling pulsars are pulsars whose observed flux occasionally disappears, but the mechanism behind the cessation is not well understood. Motivated by the correlation between pulse width and nulling fraction found in Sheikh & MacDonald, we compile all 378 nulling pulsars to date with their pulse widths in a machine-readable table. We also include the observing frequency and time resolution of each pulse width measurement. Such a table will be useful for future studies of this population.
Suborbital rockets that fly focal-plane cameras that need to be cooled to optimize their operation face a series of challenges around their operation.These include maintaining a high-quality vacuum and the cooling of the detectors in a controlled way. These challenges are further heightened by the requirement that no current flows through the payload systems while the rocket motors are being armed. This paper discusses the novel pumping and cooling system implemented for the 2022 launch of the Rockets for Extended-source X-ray Spectroscopy (tREXS), including the use of a magnetic umbilical to connect the vacuum foreline to the rocket skin.