Probing the scale of ALP interactions with Fermi blazars

Reesman, Rebecca; Walker, T. W.

doi:10.1088/1475-7516/2014/08/021

Cited by 20 publications

(13 citation statements)

References 63 publications

(121 reference statements)

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“…3. We assume the γ rays will not convert to axionlike particles or avoid absorption via some other exotic mechanism (e.g., de Angelis et al 2007;Sánchez-Conde et al 2009;Reesman & Walker 2014;Meyer et al 2014) and that their absorption is correctly described by the EBL model used. We use three EBL models, the "Model C" model of Finke et al (2010), the lower limit model of Kneiske & Dole (2010), and the model of Franceschini et al (2008).…”

Section: Methods For Constraining Modelsmentioning

confidence: 99%

Constraints on the Intergalactic Magnetic Field With Gamma-Ray Observations of Blazars

Finke

Reyes

Georganopoulos

et al. 2015

ApJ

122

143

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Distant BL Lacertae objects emit γ rays which interact with the extragalactic background light (EBL), creating electron-positron pairs, and reducing the flux measured by ground-based imaging atmospheric Cherenkov telescopes (IACTs) at very-high energies (VHE). These pairs can Comptonscatter the cosmic microwave background, creating a γ-ray signature at slightly lower energies observable by the Fermi Large Area Telescope (LAT). This signal is strongly dependent on the intergalactic magnetic field (IGMF) strength (B) and its coherence length (L B ). We use IACT spectra taken from the literature for 5 VHE-detected BL Lac objects, and combine it with LAT spectra for these sources to constrain these IGMF parameters. Low B values can be ruled out by the constraint that the cascade flux cannot exceed that observed by the LAT. High values of B can be ruled out from the constraint that the EBL-deabsorbed IACT spectrum cannot be greater than the LAT spectrum extrapolated into the VHE band, unless the cascade spectrum contributes a sizable fraction of the LAT flux. We rule out low B values (B 10 −19 G for L B ≥ 1 Mpc) at > 5σ in all trials with different EBL models and data selection, except when using > 1 GeV spectra and the lowest EBL models. We were not able to constrain high values of B.

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Section: Methods For Constraining Modelsmentioning

confidence: 99%

Constraints on the Intergalactic Magnetic Field With Gamma-Ray Observations of Blazars

Finke

Reyes

Georganopoulos

et al. 2015

ApJ

122

143

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“…The γ-ray data have been widely used to search for ALP signals [16][17][18][19][20][21][22][23][24][25]. The Fermi Collaboration searched for ALPs from the radio galaxy NGC 1275, located in the Persus cluster, which has relatively good magnetic field measurements.…”

Section: Introductionmentioning

confidence: 99%

Searching for spectral oscillations due to photon-axionlike particle conversion using the Fermi-LAT observations of bright supernova remnants

et al. 2018

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Axionlike-particles (ALPs) are one promising type of dark matter candidate particle that may generate detectable effects on γ-ray spectra other than the canonical weakly interacting massive particles. In this work we search for such oscillation effects in the spectra of supernova remnants caused by the photon-ALP conversion, using the Fermi Large Area Telescope data. Three bright supernova remnants, IC443, W44, and W51C, are analyzed. The inclusion of photon-ALP oscillations yields an improved fit to the γ-ray spectrum of IC443, which gives a statistical significance of 4.2σ in favor of such spectral oscillation. However, the best-fit parameters of ALPs (ma = 6.6 neV, gaγ = 13.4 × 10 −11 GeV −1 ) are in tension with the upper bound (gaγ < 6.6 × 10 −11 GeV −1 ) set by the CAST experiment. It is difficult to explain the results using the systematic uncertainties of the flux measurements. We speculate that the "irregularity" displayed in the spectrum of IC443 may be due to the superposition of the emission from different parts of the remnant.PACS numbers: 95.35.+d, 95.85.Pw, 98.58.Mj

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“…More explicitly, the conversion between photons and ALPs will lead to oscillation or absorption structures in the observed spectrum, while the signals predicted by a standard astrophysical radiation mechanism usually have continuous spectrum. A wide range of the parameter space of ALP model has been probed according to observations from various target sources [13,14,15,16,17,18,19,20,21,22,23,24,25,26,27,28,29,30,31,32,33] The photon-ALP oscillation can also account for the problem of low observed opacity of the Universe for TeV photons. Very high energy (VHE) photons travelling in the space will interact with the extragalactic background light (EBL) and transform to electron/positron pairs, which prevent them from propagating a long distance.…”

Section: Introductionmentioning

confidence: 99%

Revisiting the analysis of axion-like particles with the Fermi-LAT gamma-ray observation of NGC1275

Cheng,

He,

Liang

et al. 2020

Preprint

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In this work, we re-analyze the Fermi-LAT observation of NGC 1275 to search for axion-like particle (ALP) effects and constrain ALP parameters. Instead of fitting the observed spectrum with ALP models, we adopt a new method for the analysis of this source which calculates the irregularity of the spectrum. With the newly used method, we find no spectral oscillation for the NGC 1275 and rule out couplings g aγ > 3 × 10 −12 GeV −1 around ALP mass of m a ∼ 1 neV at 95% confidence level, which is more stringent than the previous results. We also show that the constraints can be further improved by combining the observation of PKS 2155-304. We suggest that with more sources taken into account, we could obtain a much wider exclusion region.

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Probing the scale of ALP interactions with Fermi blazars

Cited by 20 publications

References 63 publications

Constraints on the Intergalactic Magnetic Field With Gamma-Ray Observations of Blazars

Constraints on the Intergalactic Magnetic Field With Gamma-Ray Observations of Blazars

Searching for spectral oscillations due to photon-axionlike particle conversion using the Fermi-LAT observations of bright supernova remnants

Revisiting the analysis of axion-like particles with the Fermi-LAT gamma-ray observation of NGC1275

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