Discovery and Timing of Three Millisecond Pulsars in Radio and Gamma-Rays with the Giant Metrewave Radio Telescope and Fermi Large Area Telescope

Bhattacharyya, Bhaswati; Roy, Jayanta; Johnson, T. J.; Ray, Paul S.; Freire, P. C. C.; Gupta, Yashwant; Bhattacharya, Dipankar; A., Kaninghat,; Stappers, B. W.; Ferrara, E. C.; Sengupta, Sujan; Rathour, Rajeev Singh; Kerr, M.; Smith, David A.; Parkinson, P. M. Saz; Ransom, Scott M.; Michelson, P. F.

doi:10.3847/1538-4357/abe4d5

Cited by 16 publications

(11 citation statements)

References 48 publications

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“…LoTSS sources associated with the TULIPP pulsar discoveries or re-detections of known pulsars are noted using and †, respectively, and they are also summarised in Table 2. Furthermore, the LoTSS source noted using * is coincident with PSR J0248+4230, recently discovered using the GMRT at 322 MHz (Bhattacharyya et al 2021) and further discussed in Section 5.2.…”

Section: Pulsar Search Pipelinesmentioning

confidence: 61%

“…Two TULIPP candidates coincident with γ-ray sources have indeed been searched for radio pulsations at higher radio frequencies. The linearly polarised source ILT J024831.01+423020.3, coincident with 4FGL J0248.6+4230 (Abdollahi et al 2020), was (more recently than our TULIPP observations) discovered to be an MSP (PSR J0248+4230) using a 30-min Giant Metrewave Radio Telescope (GMRT) observation at 322 MHz (Bhattacharyya et al 2021). PSR J0248+4230 is an isolated MSP with P = 2.6 ms, DM=48.2 pc cm −3 (the pulse profile shows significant dispersion smearing at 322 MHz), a steep spectral index (α = −3.3), and < 2σ agreement between the sky positions from the LoTSS and GMRT images (Bhattacharyya et al 2021).…”

Section: Non-detection Of Other Polarised Sources As Pulsarsmentioning

confidence: 70%

“…The linearly polarised source ILT J024831.01+423020.3, coincident with 4FGL J0248.6+4230 (Abdollahi et al 2020), was (more recently than our TULIPP observations) discovered to be an MSP (PSR J0248+4230) using a 30-min Giant Metrewave Radio Telescope (GMRT) observation at 322 MHz (Bhattacharyya et al 2021). PSR J0248+4230 is an isolated MSP with P = 2.6 ms, DM=48.2 pc cm −3 (the pulse profile shows significant dispersion smearing at 322 MHz), a steep spectral index (α = −3.3), and < 2σ agreement between the sky positions from the LoTSS and GMRT images (Bhattacharyya et al 2021). After we re-examined the Presto outputs from the two LOFAR observations of ILT J024831.01+423020.3, we found that PSR J0248+4230 was only detected as a 9σ candidate (ranked 29 out of 200) in one observation.…”

Section: Non-detection Of Other Polarised Sources As Pulsarsmentioning

confidence: 70%

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Searching for pulsars associated with polarised point sources using LOFAR: Initial discoveries from the TULIPP project

Sobey

Bassa

O’Sullivan

et al. 2022

A&A

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Discovering radio pulsars, particularly millisecond pulsars (MSPs), is important for a range of astrophysical applications, such as testing theories of gravity or probing the magneto-ionic interstellar medium. We aim to discover pulsars that may have been missed in previous pulsar searches by leveraging known pulsar observables (primarily polarisation) in the sensitive, low-frequency radio images from the Low-Frequency Array (LOFAR) Two-metre Sky Survey (LoTSS), and have commenced the Targeted search, using LoTSS images, for polarised pulsars (TULIPP) survey. For this survey, we identified linearly and circularly polarised point sources with flux densities brighter than 2 mJy in LoTSS images at a centre frequency of 144 MHz with a 48 MHz bandwidth. Over 40 known pulsars, half of which are MSPs, were detected as polarised sources in the LoTSS images and excluded from the survey. We have obtained beam-formed LOFAR observations of 30 candidates, which were searched for pulsations using coherent de-dispersion. Here, we present the results of the first year of the TULIPP survey. We discovered two pulsars, PSRs J1049+5822 and J1602+3901, with rotational periods of P = 0.73 s and 3.7 ms, respectively. We also detected a further five known pulsars (two slowly-rotating pulsars and three MSPs) for which accurate sky positions were not available to allow a unique cross-match with LoTSS sources. This targeted survey presents a relatively efficient method by which pulsars, particularly MSPs, may be discovered using the flexible observing modes of sensitive radio telescopes such as the Square Kilometre Array and its pathfinders/precursors, particularly since wide-area all-sky surveys using coherent de-dispersion are currently computationally infeasible.

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Section: Pulsar Search Pipelinesmentioning

confidence: 61%

Section: Non-detection Of Other Polarised Sources As Pulsarsmentioning

confidence: 70%

Section: Non-detection Of Other Polarised Sources As Pulsarsmentioning

confidence: 70%

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Searching for pulsars associated with polarised point sources using LOFAR: Initial discoveries from the TULIPP project

Sobey

Bassa

O’Sullivan

et al. 2022

A&A

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“…The GMRT has long been one of the most sensitive telescopes at low radio frequencies, and for that reason, it has played an important role in discovering steep-spectrum pulsars (e.g. Freire et al 2004;Bhattacharyya et al 2016;Joshi et al 2009;Bhattacharyya et al 2021). With the recently installed sensitive receivers operating at lower system temperatures covering a wide bandwidth of ∼ 200 MHz (more than ten times that of the GMRT), along with the installation of a real-time coherent de-dispersion facility, the uGMRT represents a significant improvement in sensitivity compared to the GMRT.…”

Section: Introductionmentioning

confidence: 99%

Upgraded GMRT survey for pulsars in globular clusters

Gautam

Ridolfi

Freire

et al. 2022

A&A

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Context. Globular clusters (GCs) contain a unique pulsar population, with many exotic systems that can form only in their dense stellar environments. Such systems are potentially very interesting for new tests of gravity theories and neutron-star mass measurements. Aims. The leap in sensitivity of the upgraded Giant Metrewave Radio Telescope (uGMRT) in India, especially at low radio frequencies (< 1 GHz), motivated a new search for radio pulsars in a group of eight southern GCs. We aim to image these clusters in order to have independent measurements of the radio fluxes of known pulsars and the identification of bright radio sources that could be pulsars missed by pulsation search pipelines due to their inherent limitations. Methods. The observations were conducted at 650 MHz (Band 4 receivers) on Terzan 5, NGC 6441, NGC 6440, and NGC 6544, and at 400 MHz (Band 3 receivers) on NGC 6652, NGC 6539, NGC 1851, and M 30. Segmented acceleration and jerk searches were performed on the data. Simultaneously, we obtained interferometric data on these clusters, which were later converted into radio images.Results. We discovered PSR J1835−3259B, a 1.83-ms pulsar in NGC 6652; this is in a near-circular wide orbit of 28.7-hr with an unidentified low-mass (∼ 0.2) companion, likely a helium white dwarf. We derived a ten-year timing solution for this system. We also present measurements of scattering, flux densities, and spectral indices for some of the previously known pulsars in these GCs. Conclusions. A significant fraction of the pulsars in these clusters have steep spectral indices. Additionally, we detected eight radio point sources not associated with any known pulsar positions in the radio images. There are four newly identified sources, three in NGC 6652 and one in NGC 6539, as well as one previously identified source in NGC 1851, NGC 6440, NGC 6544, and Terzan 5. Surprisingly, our images show that our newly discovered pulsar, PSR J1835−3259B, is the brightest pulsar in all GCs we have imaged; like other pulsars with broad profiles (Terzan 5 C and O), its flux density in the radio images is much larger than in its pulsations. This indicates that their pulsed emission is only a fraction of their total emission. The detection of radio sources outside the core radii but well within the tidal radii of these clusters show that future GC surveys should complement the search analysis by using the imaging capability of interferometers, and preferentially synthesise large number of search beams in order to obtain a larger field of view.

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“…The Large Area Telescope on the Fermi Gamma-ray Space Telescope detects many known and new MSPs. 2 Of the 276 γray pulsars detected to date, 127 are MSPs, of which 95 are Fermi discoveries, e.g., Bhattacharyya et al (2021). Follow-up radio pulsar searches of unidentified Fermi source positions identifies the pulsar counterpart, and continued timing measures its orbital parameters.…”

Section: Introductionmentioning

confidence: 99%

Luminous Optical and X-Ray Flaring of the Putative Redback Millisecond Pulsar 1FGL J0523.5–2529

Halpern

Perez

Bogdanov

2022

ApJ

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Several redback and black widow millisecond pulsar binaries have episodes of flaring in X-rays and optical. We initially detected such behavior from the Fermi selected redback candidate 1FGL J0523.5–2529 during optical time-series monitoring. Triggered observations with the Neil Gehrels Swift Observatory over the next ≈100 days showed episodic flaring in X-rays with luminosity up to 8 × 1033 erg s−1 (∼100 times the minimum), and a comparable luminosity in the optical/UV, with similar power-law spectra of f ν ∝ ν −0.7. These are the most luminous flares seen in any nonaccreting “spider” pulsar system, which may be related to the large size of the companion through the fraction of the pulsar wind that it or its ablated wind intercepts. Simultaneously with an optical flare, we see Balmer line and He i emission, not previously known in this object, which is evidence of a stellar wind that may also inhibit detection of radio pulsations. The quiescent optical light curves, while dominated by ellipsoidal modulation, show evidence of variable nonuniform temperature that could be due either to large starspots or asymmetric heating of the companion by the pulsar. This may explain a previous measurement of unusual nonzero orbital eccentricity as, alternatively, distortion of the radial-velocity curve by the surface temperature distribution of the large companion.

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Discovery and Timing of Three Millisecond Pulsars in Radio and Gamma-Rays with the Giant Metrewave Radio Telescope and Fermi Large Area Telescope

Cited by 16 publications

References 48 publications

Searching for pulsars associated with polarised point sources using LOFAR: Initial discoveries from the TULIPP project

Searching for pulsars associated with polarised point sources using LOFAR: Initial discoveries from the TULIPP project

Upgraded GMRT survey for pulsars in globular clusters

Luminous Optical and X-Ray Flaring of the Putative Redback Millisecond Pulsar 1FGL J0523.5–2529

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