Wide-band, low-frequency pulse profiles of 100 radio pulsars with LOFAR

Pilia, M.; Hessels, J. W. T.; Stappers, B. W.; Kondratiev, V. I.; Krämer, M.; Leeuwen, J. van; Weltevrede, P.; Lyne, A. G.; Zagkouris, K.; Hassall, T. E.; Bilous, A. V.; Breton, R. P.; Falcke, H.; Grießmeier, Jean-Mathias; Keane, E. F.; Karastergiou, A.; Kuniyoshi, M.; Noutsos, A.; Osłowski, S.; Serylak, M.; Sobey, C.; Veen, S. ter; Alexov, A.; Anderson, J. M.; Asgekar, A.; Avruch, I. M.; Bell, M. E.; Bentum, Mark J.; Bernardi, G.; Bîrzan, L.; Bonafede, A.; Breitling, F.; Broderick, J. W.; Brüggen, M.; Ciardi, B.; Corbel, S.; Geus, E. de; Jong, A. de; Deller, Adam T.; Duscha, S.; Eislöffel, J.; Fallows, R. A.; Fender, R. P.; Ferrari, C.; Frieswijk, W.; Garrett, M. A.; Gunst, A. W.; Hamaker, J. P.; Heald, G.; Horneffer, A.; Jonker, P. G.; Juette, E.; Küper, G.; Maat, P.; Mann, G.; Markoff, Sera; McFadden, R.; McKay-Bukowski, D.; Miller-Jones, J. C. A.; Nelles, A.; Paas, H.; Pandey-Pommier, M.; Pietka, M.; Pizzo, R.; Polatidis, A. G.; Reich, W.; Röttgering, H. J. A.; Rowlinson, A.; Schwarz, Dominik J.; Smirnov, O.; Steinmetz, Matthias; Stewart, A.; Swinbank, J.; Tagger, M.; Tang, Y.; Tasse, C.; Thoudam, Satyendra; Toribio, M. C.; Horst, A. J. van der; Vermeulen, R. C.; Vocks, C.; Weeren, R. J. van; Wijers, R. A. M. J.; Wijnands, Rudy; Wijnholds, Stefan J.; Wucknitz, O.; Zarka, Philippe

doi:10.1051/0004-6361/201425196

Cited by 69 publications

(49 citation statements)

References 79 publications

(122 reference statements)

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“…This is different from what is generally observed in normal pulsars (see e.g. Thorsett 1991;Xilouris et al 1996;Pilia et al 2016), and may result from a small radio emission region in the very compact magnetospheres of MSPs. Kramer et al (1998) also show that MSPs are somewhat less luminous and less efficient radio emitters than normal pulsars, with isolated MSPs being even less luminous than their binary counterparts.…”

Section: Introductioncontrasting

confidence: 96%

A LOFAR census of millisecond pulsars

Kondratiev

Verbiest

Hessels

et al. 2016

A&A

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109

148

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We report the detection of 48 millisecond pulsars (MSPs) out of 75 observed thus far using the LOw-Frequency ARray (LOFAR) in the frequency range 110-188 MHz. We have also detected three MSPs out of nine observed in the frequency range 38-77 MHz. This is the largest sample of MSPs ever observed at these low frequencies, and half of the detected MSPs were observed for the first time at frequencies below 200 MHz. We present the average pulse profiles of the detected MSPs, their effective pulse widths, and flux densities and compare these with higher observing frequencies. The flux-calibrated, multifrequency LOFAR pulse profiles are publicly available via the European Pulsar Network Database of Pulsar Profiles. We also present average values of dispersion measures (DM) and discuss DM and profile variations. About 35% of the MSPs show strong narrow profiles, another 25% exhibit scattered profiles, and the rest are only weakly detected. A qualitative comparison of the LOFAR MSP profiles with those at higher radio frequencies shows constant separation between profile components. Similarly, the profile widths are consistent with those observed at higher frequencies, unless scattering dominates at the lowest frequencies. This is very different from what is observed for normal pulsars and suggests a compact emission region in the MSP magnetosphere. The amplitude ratio of the profile components, on the other hand, can dramatically change towards low frequencies, often with the trailing component becoming dominant. As previously demonstrated this can be caused by aberration and retardation. This data set enables high-precision studies of pulse profile evolution with frequency, dispersion, Faraday rotation, and scattering in the interstellar medium. Characterising and correcting these systematic effects may improve pulsar-timing precision at higher observing frequencies, where pulsar timing array projects aim to directly detect gravitational waves.

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Section: Introductioncontrasting

confidence: 96%

A LOFAR census of millisecond pulsars

Kondratiev

Verbiest

Hessels

et al. 2016

A&A

Self Cite

109

148

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“…We should note that the pulsar population represented in this census is biased by the selection method, essentially based on the previous detections of (Stovall et al 2015;Pilia et al 2016;Kondratiev et al 2016;Bilous et al 2016). It does not take into account pulsars that have not been detected in the HBA range.…”

Section: Resultsmentioning

confidence: 99%

“…B0611+22 and B0656+14 were previously reported as a detections with flux densities (Izvekova et al 1981, 180 mJy and 60 mJy at 85 MHz respectively), which are compatible with our upper limits of 337 mJy and 77 mJy. We expected to detect J0921+6254 (detected in Pilia et al 2016, but with no measured flux density). The pulsar was detected by the LOFAR core LBA census (Bilous et al 2019) with a mean flux density of 41±22 mJy, which is consistent with our upper limit of 58 mJy.…”

Section: Upper Limits For Non-detectionsmentioning

confidence: 89%

“…At frequencies below 100 MHz, the number of pulsars detected via their periodic, pulsed radio emission is considerably lower: 40 pulsars have been detected by UTR-2 (Zakharenko et al 2013); 44 by LWA (Dowell et al 2013;Stovall et al 2015); 28 non-recycled pulsars and 3 millisecond pulsars by LOFAR-LBA (Pilia et al 2016;Kondratiev et al 2016); and 2 millisecond pulsars by MWA (Bhat et al 2018). Two additional pulsars have been previously reported at low significance (<5σ) by Reyes et al (1980) and Deshpande & Radhakrishnan (1992), and three additional pulsars have been reported by Izvekova et al (1981, without pulse profiles).…”

Section: Introductionmentioning

confidence: 99%

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A census of the pulsar population observed with the international LOFAR station FR606 at low frequencies (25–80 MHz)

Bondonneau

Grießmeier

Theureau

et al. 2020

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Context. To date, only 69 pulsars have been identified with a detected pulsed radio emission below 100 MHz. A LOFARcore LBA census and a dedicated campaign with the Nançay LOFAR station in stand-alone mode were carried out in the years 2014−2017 in order to extend the known population in this frequency range. Aims. In this paper, we aim to extend the sample of known radio pulsars at low frequencies and to produce a catalogue in the frequency range of 25-80 MHz. This will allow future studies to probe the local Galactic pulsar population, in addition to helping explain their emission mechanism, better characterising the low-frequency turnover in their spectra, and obtaining new information about the interstellar medium through the study of dispersion, scattering, and scintillation. Methods. We observed 102 pulsars that are known to emit radio pulses below 200 MHz and with declination above −30 • . We used the the Low Band Antennas (LBA) of the LOw Frequency ARray (LOFAR) international station FR606 at the Nançay Radio Observatory in stand-alone mode, recording data between 25-80 MHz. Results. Out of our sample of 102 pulsars, we detected 64. We confirmed the existence of ten pulsars detected below 100 MHz by the LOFAR LBA census for the first time (Bilous et al. 2019) and we added two more pulsars that had never before been detected in this frequency range. We provided average pulse profiles, DM values, and mean flux densities (or upper limits in the case of non-detections). The comparison with previously published results allows us to identify a hitherto unknown spectral turnover for five pulsars, confirming the expectation that spectral turnovers are a widespread phenomenon.

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“…The study highlighted the importance of low-frequency study of polarisation properties to probe both the effects of pulsar magnetosphere and the interstellar medium that are more pronounced. Pilia et al (2016) studied the pulse profiles of 100 pulsars with the LOFAR HBAs at frequencies of 120−167 MHz and 26 pulsars with the LOFAR Low Band Antennas (LBAs) at frequencies of 15−62 MHz, and compared them with archival observations at 350 and 1400 MHz. They found that the frequency evolution of most of the pulsars follow the radius-frequency-mapping model (RFM model, Ruderman & Sutherland 1975;Cordes 1978), where the width of the pulse profile of a pulsar increases with decreasing observing frequency.…”

mentioning

confidence: 99%

The LOFAR Tied-Array all-sky survey: Timing of 21 pulsars including the first binary pulsar discovered with LOFAR

Tan

Bassa

Cooper

et al. 2020

Monthly Notices of the Royal Astronomical Society

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We report on the multi-frequency timing observations of 21 pulsars discovered in the LOFAR Tied-Array All-Sky Survey (LOTAAS). The timing data were taken at central frequencies of 149 MHz (LOFAR) as well as 334 and 1532 MHz (Lovell Telecope). The sample of pulsars includes 20 isolated pulsars and the first binary pulsar discovered by the survey, PSR J1658+3630. We modelled the timing properties of the pulsars, which showed that they have, on average, larger characteristic ages. We present the pulse profiles of the pulsars across the three observing bands, where PSR J1643+1338 showed profile evolution that appears not to be well-described by the radius-to-frequencymapping model. Furthermore, we modelled the spectra of the pulsars across the same observing bands, using a simple power law, and found an average spectral index of −1.9 ± 0.5. Amongst the pulsars studied here, PSR J1657+3304 showed large flux density variations of a factor of 10 over 300 days, as well as mode changing and nulling on timescales of a few minutes. We modelled the rotational and orbital properties of PSR J1658+3630, which has a spin period of 33 ms in a binary orbit of 3.0 days with a companion of minimum mass of 0.87M , likely a Carbon-Oxygen or Oxygen-Neon-Magnesium type white dwarf. PSR J1658+3630 has a dispersion measure of 3.0 pc cm −3 , making it possibly one of the closest binary pulsars known.

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Wide-band, low-frequency pulse profiles of 100 radio pulsars with LOFAR

Cited by 69 publications

References 79 publications

A LOFAR census of millisecond pulsars

A LOFAR census of millisecond pulsars

A census of the pulsar population observed with the international LOFAR station FR606 at low frequencies (25–80 MHz)

The LOFAR Tied-Array all-sky survey: Timing of 21 pulsars including the first binary pulsar discovered with LOFAR

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