Logo
ScienceStack
Table of Contents
Fetching ...
Sign In

Search for TeV emission from spider millisecond pulsars with HAWC

R. Alfaro, E. Anita-Rangel, M. Araya, J. C. Arteaga-Velázquez, D. Avila Rojas, H. A. Ayala Solares, R. Babu, P. Bangale, E. Belmont-Moreno, A. Bernal, F. Calore, T. Capistrán, A. Carramiñana, S. Casanova, A. L. Colmenero-Cesar, U. Cotti, J. Cotzomi, S. Coutiño de León, E. De la Fuente, P. Desiati, N. Di Lalla, R. Diaz Hernandez, M. A. DuVernois, J. C. Díaz-Vélez, K. Engel, T. Ergin, C. Espinoza, K. Fang, N. Fraija, S. Fraija, J. A. García-González, F. Garfias, A. Galván-Gámez, N. Ghosh, A. Gonzalez Muñoz, M. M. González, J. A. González, J. A. Goodman, S. Groetsch, D. Guevel, J. Gyeong, J. P. Harding, S. Hernández-Cadena, I. Herzog, D. Huang, F. Hueyotl-Zahuantitla, P. Hüntemeyer, A. Iriarte, S. Kaufmann, D. Kieda, K. Leavitt, W. H. Lee, H. León Vargas, A. L. Longinotti, G. Luis-Raya, K. Malone, S. Manconi, O. Martinez, J. Martínez-Castro, J. A. Matthews, P. Miranda-Romagnoli, J. A. Morales-Soto, M. Mostafá, M. Najafi, L. Nellen, R. Noriega-Papaqui, N. Omodei, M. Osorio-Archila, E. Ponce, Y. Pérez Araujo, C. D. Rho, A. Rodriguez Parra, D. Rosa-González, M. Roth, H. Salazar, A. Sandoval, M. Schneider, J. Serna-Franco, M. Shin, Y. Son, R. W. Springer, O. Tibolla, K. Tollefson, I. Torres, F. Ureña-Mena, E. Varela, X. Wang, Z. Wang, H. Wu, S. Yu, X. Zhang, H. Zhou, C. de León

Abstract

Millisecond pulsars (MSPs) are observed to emit multi-wavelength radiation, from radio to GeV. Spider MSPs, which interact with their low-mass companion in close orbit (orbital periods $< 1$ day), may lead to strong intrabinary shocks that can further accelerate electron and positron pairs produced in the magnetosphere, possibly emitting very-high-energy (0.1--100 TeV; VHE) photons through inverse Compton scattering. Using 2565 days of HAWC Pass 5 data, we search for VHE emission from spider MSPs and present upper limits on individual sources. We also perform a stacking analysis to examine whether the two sets of spider systems, classified as redbacks and black widows depending on the companion mass, exhibit different spectral properties. Our study places constraints on TeV emission from MSPs and suggests that they are unlikely to contribute significantly to the Galactic diffuse emission at TeV and higher energies.

Search for TeV emission from spider millisecond pulsars with HAWC

Abstract

Millisecond pulsars (MSPs) are observed to emit multi-wavelength radiation, from radio to GeV. Spider MSPs, which interact with their low-mass companion in close orbit (orbital periods day), may lead to strong intrabinary shocks that can further accelerate electron and positron pairs produced in the magnetosphere, possibly emitting very-high-energy (0.1--100 TeV; VHE) photons through inverse Compton scattering. Using 2565 days of HAWC Pass 5 data, we search for VHE emission from spider MSPs and present upper limits on individual sources. We also perform a stacking analysis to examine whether the two sets of spider systems, classified as redbacks and black widows depending on the companion mass, exhibit different spectral properties. Our study places constraints on TeV emission from MSPs and suggests that they are unlikely to contribute significantly to the Galactic diffuse emission at TeV and higher energies.

Paper Structure

This paper contains 14 sections, 4 equations, 5 figures, 4 tables.

Table of Contents

  1. Introduction
  2. Method
  3. Telescope and data selection
  4. Millisecond pulsars sample
  5. Minimal source fit
  6. Multi-source fit
  7. Stacking analysis
  8. Results
  9. Minimal source fits
  10. Multi-source fits
  11. Stacking analysis
  12. Systematic Uncertainties
  13. Discussion and conclusion
  14. Acknowledgements

Figures (5)

  • Figure 1: Locations of the 43 spider MSPs in our sample in Galactic coordinates. The 15 redbacks are shown as yellow circles and the 28 black widows are shown as green triangles. The color map indicates the significance of point-like sources in HAWC's field-of-view. The significance is approximated as the square root of the test statistics defined in equation \ref{['eqn:TS']} assuming a spectral index $p=2.7$wilks1938.
  • Figure 2: Significance maps of the data (left), model (middle) and residual emission (right) in the region around PSR J1952+2630 Fig 3. The fit uses a circular ROI of radius $4.0 ^\circ$ centered at the pulsar, indicated by a red circle. A faint extended source, 4HWC J1945+2434, and three bright sources with small extensions (4HWC J1958+2851, 4HWC J1953+2837, 4HWC J1952+2925) are included in the multi-source fit. The white cross indicates the location of PSR J1952+2630. The dashed lines represent the extensions of the 4HWC sources.
  • Figure 3: Same as Figure \ref{['fig:J1952+2630']} but for the region around PSR J1957+2516. This multi-source fit uses a circular ROI of radius $4.0 ^\circ$ (indicated by a red circle) centered at PSR J1957+2516 and includes 4HWC J1945+2434, 4HWC J1958+2851, 4HWC J1953+2837, and 4HWC J1952+2925. The white cross at the center represents the location of PSR J1957+2516.
  • Figure 4: Same as Figure \ref{['fig:J1952+2630']} but for the region around PSR B1957+20. This fit uses a circular ROI of radius $4.0 ^\circ$ (indicated by a red circle) centered at PSR B1957+20 and includes 4HWC J1945+2434. The white cross at the center represents the location of PSR B1957+20.
  • Figure 5: Upper limits as a function of energy on the average flux of MSPs in our sample. The dark and light gray bands correspond to the 68% and 90% containment, respectively, for expected upper limits obtained by performing the same analysis but with simulated background data ($\mathcal{H}_0$). We report the results for the full set, the redbacks only, and the black widows only in the upper-left, upper-right, and lower panels, respectively.