Using the Green Bank Telescope (GBT), astronomers have made a significant discovery in the globular cluster known as Terzan 6. They detected a new millisecond pulsar (MSP) that is likely associated with this cluster. This finding was detailed in a research paper published on September 17 on the pre-print server arXiv.
What are Pulsars?
Pulsars are highly magnetized, rotating neutron stars that emit beams of electromagnetic radiation. The most rapidly rotating pulsars, known as millisecond pulsars (MSPs), have rotation periods of less than 30 milliseconds. It is believed that MSPs form in binary systems when a more massive star evolves into a neutron star and is subsequently spun up through the accretion of matter from its companion star.
Overview of Terzan 6
Terzan 6 is a metal-rich core-collapsed Galactic globular cluster located approximately 21,800 light years from Earth. Despite being known for decades, no pulsars had been detected in this cluster until now. However, its high stellar encounter rate suggests it could harbor dozens of such objects.
The Discovery
A team of astronomers led by Shi-Jie Gao from Nanjing University, China, reported the detection of a new MSP, which may be the first known pulsar in Terzan 6. This discovery resulted from a targeted search of the cluster using the GBT at C-band (4–8 GHz).
Characteristics of PSR J1751–3116A
- Pulsar Name: PSR J1751–3116A
- Spin Period: Approximately 5.33 milliseconds
- Dispersion Measure: About 383.08 pc/cm³
The dispersion measure obtained strongly supports the association between PSR J1751–3116A and Terzan 6.
Flux Density Measurements
The study found that the flux density of PSR J1751–3116A at 6.0 GHz is approximately 3.0 µJy. Assuming a spectral index of -1.4, the estimated flux density at 1.44 GHz is around 23 µJy.
Implications of the Discovery
The authors suggest that PSR J1751–3116A is an isolated millisecond pulsar, aligning with the classification of Terzan 6 as a core-collapsed cluster. They theorize that PSR J1751–3116A may have formed through dynamical interactions within the cluster.
Future Research Directions
The researchers hope to discover more pulsars in Terzan 6 using existing radio telescopes at higher frequencies. They emphasize the need for more sensitive searches, such as using GBT and MeerKAT, as part of projects like TRAPUM, which could lead to further pulsar discoveries in Terzan 6.
Conclusion
The detection of PSR J1751–3116A marks an exciting advancement in the study of globular clusters and pulsars. The findings highlight the potential for ongoing research and exploration in Terzan 6, given its high stellar encounter rate.
Multiple Choice Questions (MCQs):
- What is the spin period of the newly discovered pulsar PSR J1751–3116A?
- A) 3.0 milliseconds
- B) 5.33 milliseconds
- C) 30 milliseconds
- D) 21,800 milliseconds
Answer: B) 5.33 milliseconds
- What type of astronomical object is a pulsar?
- A) A type of black hole
- B) A rotating neutron star
- C) A red giant star
- D) A white dwarf star
Answer: B) A rotating neutron star
- What is the approximate distance of Terzan 6 from Earth?
- A) 3,000 light years
- B) 10,000 light years
- C) 21,800 light years
- D) 50,000 light years
Answer: C) 21,800 light years
- Which telescope was used to detect the new millisecond pulsar?
- A) Hubble Space Telescope
- B) MeerKAT
- C) Green Bank Telescope
- D) Very Large Telescope
Answer: C) Green Bank Telescope
- What does the study suggest about the formation of PSR J1751–3116A?
- A) It formed in isolation
- B) It formed through binary interactions
- C) It formed through dynamical interactions in the cluster
- D) It formed from a supernova
Answer: C) It formed through dynamical interactions in the cluster.