Discovery of a 50 millisecond pulsar in the Large Magellanic Cloud

Seward, F. D.; Harnden, F. R.; Helfand, D. J.

doi:10.1086/184388

Cited by 156 publications

(120 citation statements)

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“…With these statistics, the extended gamma-ray emission from the LMC can be resolved into several components. The brightest emission feature is located near (α J2000 , δ J2000 ) ≈ (05 h 40 m , −69 • 15 ), which is close to the massive star-forming region 30 Doradus (30 Dor) that houses the two Crab-like pulsars PSR J0540−6919 and PSR J0537−6910 (Seward et al 1984;Marshall et al 1998). Excess gamma-ray emission is also seen toward the north and the west of 30 Dor.…”

Section: Counts Mapmentioning

confidence: 93%

Observations of the Large Magellanic Cloud withFermi

Abdo

Ackermann

Ajello

et al. 2010

A&A

120

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Context. The Large Magellanic Cloud (LMC) is to date the only normal external galaxy that has been detected in high-energy gamma rays. Highenergy gamma rays trace particle acceleration processes and gamma-ray observations allow the nature and sites of acceleration to be studied. Aims. We characterise the distribution and sources of cosmic rays in the LMC from analysis of gamma-ray observations. Methods. We analyse 11 months of continuous sky-survey observations obtained with the Large Area Telescope aboard the Fermi Gamma-Ray Space Telescope and compare it to tracers of the interstellar medium and models of the gamma-ray sources in the LMC. Results. The LMC is detected at 33σ significance. The integrated >100 MeV photon flux of the LMC amounts to (2.6 ± 0.2) × 10 −7 ph cm −2 s −1 which corresponds to an energy flux of (1.6 ± 0.1) × 10 −10 erg cm −2 s −1 , with additional systematic uncertainties of < ∼ 16%. The analysis reveals the massive star forming region 30 Doradus as a bright source of gamma-ray emission in the LMC in addition to fainter emission regions found in the northern part of the galaxy. The gamma-ray emission from the LMC shows very little correlation with gas density and is rather correlated to tracers of massive star forming regions. The close confinement of gamma-ray emission to star forming regions suggests a relatively short GeV cosmic-ray proton diffusion length. Conclusions. The close correlation between cosmic-ray density and massive star tracers supports the idea that cosmic rays are accelerated in massive star forming regions as a result of the large amounts of kinetic energy that are input by the stellar winds and supernova explosions of massive stars into the interstellar medium.

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Section: Counts Mapmentioning

confidence: 93%

Observations of the Large Magellanic Cloud withFermi

Abdo

Ackermann

Ajello

et al. 2010

A&A

120

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“…PSR J0540−6919 is a 50 ms pulsar associated with the ∼1100-year old SNR 0540−69.3 and PWN N 158A (Seward et al 1984;Williams et al 2008;Brantseg et al 2014). With a spin-down luminosity ofĖ = 1.5 × 10 38 erg s −1 , it has the third largest spin-down power of any pulsar currently known, right behind that of the Crab pulsar, 4.5 × 10 38 erg s −1 (see the ATNF catalogue 6 ).…”

Section: P1: Pulsar Psr J0540−6919mentioning

confidence: 99%

Deep view of the Large Magellanic Cloud with six years ofFermi-LAT observations

Ackermann¹,

Albert²,

Atwood³

et al. 2016

A&A

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Context. The nearby Large Magellanic Cloud (LMC) provides a rare opportunity of a spatially resolved view of an external star-forming galaxy in γ-rays. The LMC was detected at 0.1-100 GeV as an extended source with CGRO/EGRET and using early observations with the Fermi-LAT. The emission was found to correlate with massive star-forming regions and to be particularly bright towards 30 Doradus. Aims. Studies of the origin and transport of cosmic rays (CRs) in the Milky Way are frequently hampered by line-of-sight confusion and poor distance determination. The LMC offers a complementary way to address these questions by revealing whether and how the γ-ray emission is connected to specific objects, populations of objects, and structures in the galaxy. Methods. We revisited the γ-ray emission from the LMC using about 73 months of Fermi-LAT P7REP data in the 0.2-100 GeV range. We developed a complete spatial and spectral model of the LMC emission, for which we tested several approaches: a simple geometrical description, template-fitting, and a physically driven model for CR-induced interstellar emission. Results. In addition to identifying PSR J0540−6919 through its pulsations, we find two hard sources positionally coincident with plerion N 157B and supernova remnant N 132D, which were also detected at TeV energies with H.E.S.S. We detect an additional soft source that is currently unidentified. Extended emission dominates the total flux from the LMC. It consists of an extended component of about the size of the galaxy and additional emission from three to four regions with degree-scale sizes. If it is interpreted as CRs interacting with interstellar gas, the large-scale emission implies a large-scale population of ∼1-100 GeV CRs with a density of ∼30% of the local Galactic value. On top of that, the three to four small-scale emission regions would correspond to enhancements of the CR density by factors 2 to 6 or higher, possibly more energetic and younger populations of CRs compared to the large-scale population. An alternative explanation is that this is emission from an unresolved population of at least two dozen objects, such as pulsars and their nebulae or supernova remnants. This small-scale extended emission has a spatial distribution that does not clearly correlate with known components of the LMC, except for a possible relation to cavities and supergiant shells. Conclusions. The Fermi-LAT GeV observations allowed us to detect individual sources in the LMC. Three of the newly discovered sources are associated with rare and extreme objects. The 30 Doradus region is prominent in GeV γ-rays because PSR J0540−6919 and N 157B are strong emitters. The extended emission from the galaxy has an unexpected spatial distribution, and observations at higher energies and in radio may help to clarify its origin.

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“…Interestingly enough, the X-ray/radio pulsar PSR B0540−69 (Seward et al 1984;Manchester et al 1993) in the Large Magellanic Clouds (LMC) has not been observed yet in the IR. With a spin-down age of ∼1700 yr, it is one of the youngest pulsars so far and is similar to the Crab in its spin period (P = 50 ms), dipolar magnetic field (B ∼ 5 × 10 12 G), and rotational energy loss rate (Ė ∼ 1.5 × 10 38 erg s −1 ).…”

Section: Introductionmentioning

confidence: 99%

The near-infrared detection of PSR B0540–69 and its nebula

Mignani

Luca

Hummel

et al. 2012

A&A

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Context. The ∼1700 year old PSR B0540−69 in the Large Magellanic Clouds (LMC) is considered the twin of the Crab pulsar because of its similar spin parameters, magnetic field, and energetics. PSR B0540−69 (V ∼ 22.5) is also one of the very few pulsars for which both optical pulsations and polarised emission have been measured. Its optical spectrum is fit by a power-law, ascribed to synchrotron radiation, like for the young Crab and Vela pulsars. At variance with them, however, a double break is required to join the X-ray and optical power-law spectra, with the first one possibly occurring in the near ultraviolet (nUV). Aims. Near-infrared (nIR) observations, never performed for PSR B0540−69, are crucial to determine whether the optical power-law spectrum extends to longer wavelengths or a new break occurs, like it happens for both the Crab and Vela pulsars in the mid-infrared (mIR), hinting at an even more complex particle energy and density distribution in the pulsar magnetosphere. Methods. We observed PSR B0540−69 in the J, H, and K S bands with the Very Large Telescope (VLT) to detect it, for the first time, in the nIR and characterise its optical-to-nIR spectrum. To disentangle the pulsar emission from that of its pulsar wind nebula (PWN), we obtained high-spatial resolution adaptive optics images with the NAOS-CONICA instrument (NACO). Results. We could clearly identify PSR B0540−69 in our J, H, and K S -band images and measure its flux (J = 20.14, H = 19.33, K S = 18.55, with an overall error of ±0.1 mag in each band). The joint fit to the available optical and nIR photometry with a powerlaw spectrum F ν ∝ ν −α gives a spectral index α = 0.70 ± 0.04, slightly more precise than measured in the optical only. This clearly implies that there is no spectral break between the optical and the nIR. We also detected, for the first time, the PSR B0540−69 PWN in the nIR. The comparison between our NACO images and Hubble Space Telescope (HST) optical ones does not reveal any apparent difference in the PWN morphology as a function of wavelength. The PWN optical-to-nIR spectrum is also fit by a single power-law, with spectral index α = 0.56 ± 0.03, slightly flatter than the pulsar's. Conclusions. Using NACO at the VLT, we obtained the first detection of PSR B0540−69 and its PWN in the nIR. Due to the small angular scale of the PWN (∼4 ) only the spatial resolution of the James Webb Space Telescope (JWST) will make it possible to extend the study of the pulsar and PWN spectrum towards the mid-IR.

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Discovery of a 50 millisecond pulsar in the Large Magellanic Cloud

Cited by 156 publications

References 0 publications

Observations of the Large Magellanic Cloud withFermi

Observations of the Large Magellanic Cloud withFermi

Deep view of the Large Magellanic Cloud with six years ofFermi-LAT observations

The near-infrared detection of PSR B0540–69 and its nebula

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