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Please use this identifier to cite or link to this item: http://hdl.handle.net/2289/7805
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dc.contributor.authorKrishnakumar, M.A.-
dc.contributor.authorManoharan, P.K.-
dc.contributor.authorJoshi, B.C.-
dc.contributor.authorGirgaonkar, R.-
dc.contributor.authorDesai, S.-
dc.contributor.authorBagchi, M.-
dc.contributor.authorNobleson, K.-
dc.contributor.authorDey, L.-
dc.contributor.authorSusobhanan, A.-
dc.contributor.authorSusarla, S.C.-
dc.contributor.authorSurnis, M.P.-
dc.contributor.authorMaan, Y.-
dc.contributor.authorGopakumar, A.-
dc.contributor.authorBasu, A.-
dc.contributor.authorBatra, N.D.-
dc.contributor.authorChoudhary, A.-
dc.contributor.authorDe, K.-
dc.contributor.authorGupta, Y.-
dc.contributor.authorNaidu, A.K.-
dc.contributor.authorPathak, D.-
dc.contributor.authorSingha, J.-
dc.contributor.authorPrabu, T.-
dc.date.accessioned2021-07-27T06:24:59Z-
dc.date.available2021-07-27T06:24:59Z-
dc.date.issued2021-07-
dc.identifier.citationAstronomy and Astrophysics, 2021, Vol.651, Article No.A5en_US
dc.identifier.issn0004-6361-
dc.identifier.issn1432-0746 (Online)-
dc.identifier.urihttp://hdl.handle.net/2289/7805-
dc.descriptionOpen Accessen_US
dc.description.abstractContext. Pulsar radio emission undergoes dispersion due to the presence of free electrons in the interstellar medium (ISM). The dispersive delay in the arrival time of the pulsar signal changes over time due to the varying ISM electron column density along the line of sight. Accurately correcting for this delay is crucial for the detection of nanohertz gravitational waves using pulsar timing arrays. Aims. We aim to demonstrate the precision in the measurement of the dispersion delay achieved by combining 400−500 MHz (BAND3) wide-band data with those at 1360−1460 MHz (BAND5) observed using the upgraded GMRT, employing two different template alignment methods. Methods. To estimate the high precision dispersion measure (DM), we measure high precision times-of-arrival (ToAs) of pulses using carefully generated templates and the currently available pulsar timing techniques. We use two different methods for aligning the templates across frequency to obtain ToAs over multiple sub-bands and therefrom measure the DMs. We study the effects of these two different methods on the measured DM values in detail. Results. We present in-band and inter-band DM estimates of four pulsars over the timescale of a year using two different template alignment methods. The DMs obtained using both these methods show only subtle differences for PSRs J1713+0747 and J1909−3744. A considerable offset is seen in the DM of PSRs J1939+2134 and J2145−0750 between the two methods. This could be due to the presence of scattering in the former and profile evolution in the latter. We find that both methods are useful but could have a systematic offset between the DMs obtained. Irrespective of the template alignment methods followed, the precision on the DMs obtained is about 10−3 pc cm−3 using only BAND3 and 10−4 pc cm−3 after combining data from BAND3 and BAND5 of the uGMRT. In a particular result, we detected a DM excess of about 5 × 10−3 pc cm−3 on 24 February 2019 for PSR J2145−0750. This excess appears to be due to the interaction region created by fast solar wind from a coronal hole and a coronal mass ejection observed from the Sun on that epoch. A detailed analysis of this interesting event is presented.en_US
dc.language.isoenen_US
dc.publisherEDP Sciencesen_US
dc.relation.urihttps://ui.adsabs.harvard.edu/abs/2021A%26A...651A...5K/abstracten_US
dc.relation.urihttps://arxiv.org/abs/2101.05334en_US
dc.relation.urihttps://doi.org/10.1051/0004-6361/202140340-
dc.rights2021 ESOen_US
dc.subjectpulsars: generalen_US
dc.subjectISM: generalen_US
dc.subjectSun: coronal mass ejections (CMEs)en_US
dc.subjectgravitational wavesen_US
dc.titleHigh precision measurements of interstellar dispersion measure with the upgraded GMRTen_US
dc.typeArticleen_US
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