2014/12/31 by A. V. Bilous, Timothy T. Pennucci, T. T. Pennucci +3 · 1 citation
Physics and Astronomy · #Astronomy #Astrophysical Phenomena and Observations #Astrophysics #Astrophysics and Cosmic Phenomena #Broadband #Crab Pulsar #Millisecond pulsar #Optics #Physics #Polarization (electrochemistry) #Pulsar #Pulsars and Gravitational Waves Research #Radio spectrum #astro-ph.HE #astro-ph.SR
paper · pdf · doi:10.1088/0004-637x/803/2/83
16 pages, 8 figures, accepted to ApJ
arxiv created 2015/02/22 · openalex publication_date 2015/04/21 · arxiv updated 2015/06/23 · openalex created_date 2025/10/10 · openalex updated_date 2026/08/05
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 first time we measure phase-resolved polarization properties and spectral indices of radio emission throughout almost all of the on-pulse window. We synthesize our findings with high-energy information to compare M28A to other known γ -ray MSPs and to speculate that M28A's radio emission originates in multiple regions within its magnetosphere (i.e., both in the slot or outer gaps near the light cylinder and at lower altitudes above the polar cap). M28A is one of a handful of pulsars that are known to emit giant radio pulses (GRPs)—short, bright radio pulses of unknown nature. We report a drop in the linear polarization of the average profile in both windows of GRP generation and also a "W"-shaped absorption feature (resembling a double notch), partly overlapping with one of the GRP windows. The GRPs themselves have broadband spectra consisting of multiple patches with Δ ν / ν ∼ 0.07. Although our time resolution was not sufficient to resolve the GRP structure on the μ s scale, we argue that GRPs from this pulsar most closely resemble the GRPs from the main pulse of the Crab pulsar, which consist of a series of narrowband nanoshots.