Six faint gamma-ray pulsars seen with the<i>Fermi</i>Large Area Telescope

Hou, X.; Smith, David A.; Guillemot, L.; Cheung, C. C.; Cognard, I.; Craig, H. A.; Espinoza, C. M.; Johnston, S.; Krämer, M.; Reimer, O.; Reposeur, T.; Shannon, R. M.; Stappers, B. W.; Weltevrede, P.

doi:10.1051/0004-6361/201424294

Cited by 25 publications

(33 citation statements)

References 52 publications

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“…We also emphasize that taking L max to be the same as that observed for the nearby MSPs is a critical assumption in these arguments and is subject to uncertainties from both the small sample size of highluminosity MSPs and large errors in MSP distances and luminosities [64][65][66]. In any case, for all but the high end of the range of L max that we consider, it is likely that the total number of point sources that are over the detection threshold is less than or comparable to the number of unassociated detected sources in the Inner Galaxy.…”

Section: Point-source Excessmentioning

confidence: 99%

Distinguishing dark matter from unresolved point sources in the Inner Galaxy with photon statistics

Lee

Lisanti

Safdi

2015

J. Cosmol. Astropart. Phys.

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Data from the Fermi Large Area Telescope suggests that there is an extended excess of GeV gamma-ray photons in the Inner Galaxy. Identifying potential astrophysical sources that contribute to this excess is an important step in verifying whether the signal originates from annihilating dark matter. In this paper, we focus on the potential contribution of unresolved point sources, such as millisecond pulsars (MSPs). We propose that the statistics of the photons-in particular, the flux probability density function (PDF) of the photon counts below the point-source detection threshold-can potentially distinguish between the darkmatter and point-source interpretations. We calculate the flux PDF via the method of generating functions for these two models of the excess. Working in the framework of Bayesian model comparison, we then demonstrate that the flux PDF can potentially provide evidence for an unresolved MSP-like point-source population.

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Section: Point-source Excessmentioning

confidence: 99%

Distinguishing dark matter from unresolved point sources in the Inner Galaxy with photon statistics

Lee

Lisanti

Safdi

2015

J. Cosmol. Astropart. Phys.

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“…For many pulsars, LAT data covering several years of observation time are needed for significant pulsation detection (e.g. Hou et al 2014). Searching for pulsations requires assigning every gamma-ray photon with the pulsar's rotational phase Φ (defined in rotations throughout the paper) at the time of emission.…”

Section: Searchmentioning

confidence: 99%

Detection and Timing of Gamma-Ray Pulsations from the 707 Hz Pulsar J0952−0607

Nieder

Clark

Bassa

et al. 2019

ApJ

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The Low-Frequency Array radio telescope discovered the 707 Hz binary millisecond pulsar (MSP) J0952−0607 in a targeted radio pulsation search of an unidentified Fermi gamma-ray source. This source shows a weak energy flux of F γ = 2.6 × 10 −12 erg cm −2 s −1 in the energy range between 100 MeV and 100 GeV. Here we report the detection of pulsed gamma-ray emission from PSR J0952−0607 in a very sensitive gamma-ray pulsation search. The pulsar's rotational, binary, and astrometric properties are measured over seven years of Fermi-Large Area Telescope data. For this we take into account the uncertainty on the shape of the gamma-ray pulse profile. We present an updated radio-timing solution now spanning more than two years and show results from optical modeling of the black-widow-type companion based on new multi-band photometric data taken with HiPERCAM on the Gran Telescopio Canarias on La Palma and ULTRACAM on the New Technology Telescope at ESO La Silla a) . PSR J0952−0607 is now the fastest-spinning pulsar for which the intrinsic spindown rate has been reliably constrained (Ṗ int 4.6 × 10 −21 s s −1 ). The inferred surface magnetic field strength of B surf 8.2 × 10 7 G is among the ten lowest of all known pulsars. This discovery is another example of an extremely fast spinning black-widow pulsar hiding within an unidentified Fermi gamma-ray source. In the future such systems might help to pin down the maximum spin frequency and the minimum surface magnetic field strength of MSPs.

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“…The density is highly structured for most of these pulsars, with unphysical steps, dips, and spikes, especially for the first few kpc: see Fig. 4 of Hou et al (2014) for examples. The DM value is small (<25 pc cm −3 ) for half of these MSPs, making Notes.…”

Section: Pulsar Selectionmentioning

confidence: 99%

The gamma-ray millisecond pulsar deathline, revisited

Guillemot

Smith

Laffon

et al. 2016

A&A

Self Cite

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Context. Millisecond pulsars (MSPs) represent nearly half of the more than 160 currently known γ-ray pulsars detected by the Large Area Telescope on the Fermi satellite, and a third of all known MSPs are seen in γ rays. The least energetic γ-ray MSPs enable us to probe the so-called deathline for high-energy emission, i.e., the spin-down luminosity limit under which pulsars (PSRs) cease to produce detectable high-energy radiation. Characterizing the MSP luminosity distribution helps to determine their contribution to the Galactic diffuse γ-ray emission. Aims. Because of the Shklovskii effect, precise proper motion and distance measurements are key ingredients for determining the spin-down luminosities of MSPs accurately. Our aim is to obtain new measurements of these parameters for γ-ray MSPs when possible, and clarify the relationship between the γ-ray luminosity of pulsars and their spin-down luminosity. Detecting low spin-down luminosity pulsars in γ rays and characterizing their spin properties is also particularly interesting for constraining the deathline for high-energy emission. Methods. We made use of the high-quality pulsar timing data recorded at the Nançay Radio Telescope over several years to characterize the properties of a selection of MSPs. For one of the pulsars, the dataset was complemented with Westerbork Synthesis Radio Telescope observations. The rotation ephemerides derived from this analysis were also used to search the LAT data for new γ-ray MSPs. Results. For the MSPs considered in this study, we obtained new transverse proper motion measurements or updated the existing ones, and placed new distance constraints for some of them, with four new timing parallax measurements. We discovered significant GeV γ-ray signals from four MSPs, i.e., PSRs J0740+6620, J0931−1902, J1455−3330, and J1730−2304. The latter is now the least energetic γ-ray pulsar found to date. Despite the improvedĖ and L γ estimates, the relationship between these two quantities remains unclear, especially at lowĖ values.

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Six faint gamma-ray pulsars seen with theFermiLarge Area Telescope

Cited by 25 publications

References 52 publications

Distinguishing dark matter from unresolved point sources in the Inner Galaxy with photon statistics

Distinguishing dark matter from unresolved point sources in the Inner Galaxy with photon statistics

Detection and Timing of Gamma-Ray Pulsations from the 707 Hz Pulsar J0952−0607

The gamma-ray millisecond pulsar deathline, revisited

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