Pulsars don’t have a single “pulsar frequency” the way spectral lines do.
Pulsars don’t have a single “pulsar frequency” the way spectral lines do — instead they emit broadband radio noise with periodic pulses, and what we observe are:
- Spin frequency (how fast the pulsar rotates), and
- Radio observing frequency (what RF band we tune to).
Here are the key ranges:
1. Spin frequencies (rotation rates)
Pulsars rotate between:
- 0.1–30 Hz for “normal” pulsars
- 30–716 Hz for millisecond pulsars (fastest known rotates at ~716 Hz)
So a pulsar with a 1-second period has a spin frequency of 1 Hz, while a 1.4-ms MSP has a spin frequency ≈ 716 Hz.
2. Radio observing frequencies (RF bands we use)
Pulsars emit broadband radio, but the most productive observing windows are:
Low frequency (30–300 MHz)
- LOFAR, LWA observations
- Strong but heavily affected by dispersion and scattering
Mid frequency (300 MHz – 3 GHz)
- Most common for pulsar astronomy
- 350 MHz, 430 MHz, 610 MHz, 1.4 GHz (L-band) are standard
- 1.4 GHz is the most widely used because dispersion/scattering are manageable
High frequency (>3 GHz)
- Used for heavily scattered pulsars, Galactic Center pulsars
- Observations at 4.5–9 GHz are common for precision timing
Summary
- Pulsars don’t emit at a single RF line — they produce broadband radio pulses.
- Spin frequency: ~0.1 to 716 Hz
- Typical observing RF: 350 MHz to 3 GHz (especially 1.4 GHz)