| Name: | Rahul Sharan |
| Affiliation: | NCRA-TIFR, Pune |
| Conference ID: | ASI2025_323 |
| Title: | Detection of nulling in millisecond pulsars using uGMRT observations |
| Authors: | Rahul Sharan, Bhaswati Bhattacharyya |
| Authors Affiliation: | Rahul Sharan, Bhaswati Bhattacharyya: National Centre for Radio Astrophysics, Pune-411007, India |
| Mode of Presentation: | Oral |
| Abstract Category: | Stars, Interstellar Medium, and Astrochemistry in Milky Way |
| Abstract: | Nulling pulsars are characterized by the absence of detectable pulsed signals. These are mostly seen in normal pulsars, and none of the millisecond pulsars (MSPs; pulsars with a spin period less than 30 ms) are known to show nulling to date. With a wide frequency coverage from 300-1500 MHz and a large collecting area, uGMRT becomes an ideal telescope for nulling studies on MSPs. We present results from an investigation, showing that the MSPs are exhibiting nulling phenomena using uGMRT observations. Our observations captured nulling in a few MSPs (J2144-5237, 0248+4230, J1646-2142 to name a few) in multiple observing epochs. We note that the effect of ionospheric scintillation is manifested in flux density variation over time and frequency, which can create confusion while identifying the underlying mechanism for nulling. We developed a new algorithm for searching nulls in time-pulse phase space, and compared our results with previous algorithms (Ritchings 1976, Kaplan et al. 2018) applied on normal pulsars. Since MSPs are intrinsically faint sources, they are classified as Intermittent Nuller (as per Konar & Deka 2019), which show nulling in a few seconds but single pulse nulls are not detected. We averaged for a few seconds and estimated the Nulling fraction (NF) and Nulling lengths (NL) of the MSPs. Finally, our study indicates that the phenomenon of nulling was not previously detected for the MSPs because of their faint nature; sensitive observations with upcoming and ongoing facilities aided with careful searching for nulling would enable us to increase the sample of nulling MSPs. This will be an important step for understanding the emission mechanism of MSPs and judging the likenesses of similar emission mechanisms for normal pulsars and MSPs. |
