Galactic Shapiro delay to the Crab pulsar and limit on weak equivalence principle violation

Desai, Shantanu and Kahya, Emre (2018) Galactic Shapiro delay to the Crab pulsar and limit on weak equivalence principle violation. The European Physical Journal C, 78 (2). pp. 1-4. ISSN 1434-6044

European Physical Journal C_78_2_1-4_2018.pdf - Published Version

Download (472kB) | Preview


We calculate the total galactic Shapiro delay to the Crab pulsar by including the contributions from the dark matter as well as baryonic matter along the line of sight. The total delay due to dark matter potential is about 3.4 days. For baryonic matter, we included the contributions from both the bulge and the disk, which are approximately 0.12 and 0.32 days respectively. The total delay from all the matter distribution is therefore 3.84 days. We also calculate the limit on violations of Weak equivalence principle by using observations of “nano-shot” giant pulses from the Crab pulsar with time-delay < 0.4 ns, as well as using time differences between radio and optical photons observed from this pulsar. Using the former, we obtain a limit on violation of Weak equivalence principle in terms of the PPN parameter 2.41 × 10 -15. From the time-difference between simultaneous optical and radio observations, we get 1.54 × 10 -9. We also point out differences in our calculation of Shapiro delay and that from two recent papers (Yang and Zhang, Phys Rev D 94(10):101501, 2016; Zhang and Gong, Astrophys J 837:134, 2017), which used the same observations to obtain a corresponding limit on Δγ.

[error in script]
IITH Creators:
IITH CreatorsORCiD
Desai, Shantanu
Item Type: Article
Subjects: Physics
Divisions: Department of Physics
Depositing User: Team Library
Date Deposited: 19 Feb 2018 07:00
Last Modified: 19 Feb 2018 07:00
Publisher URL:
OA policy:
Related URLs:

Actions (login required)

View Item View Item
Statistics for RAIITH ePrint 3796 Statistics for this ePrint Item