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Title: A Search for Transitions between States in Redbacks and Black Widows Using Seven Years of Fermi -LAT Observations

Abstract

Considering about seven years of Fermi -Large Area Telescope (LAT) data, we present a systematic search for variability that is possibly related to transitions between states in redbacks and black widow systems. The transitions are characterized by sudden and significant changes in the gamma-ray flux that persist on a timescale that is much larger than the orbital period. This phenomenology was already detected in the case of two redback systems, PSR J1023+0038 and PSR J1227−4853, which we present here. We show the existence of only one transition for each of these systems over the past seven years. We determine their spectra, establishing high-energy cutoffs at a few GeV for the high gamma-ray state of PSR J1023+0038, and for both states of PSR J1227−4853. The surveying capability of the Fermi -LAT allows further study of whether similar phenomenology has occurred in other sources. Although we have not found any evidence of a state transition for most of the studied pulsars, we note two black-widow systems, PSR J2234+0944 and PSR J1446−4701, whose apparent variabilities are reminiscent of the transitions in PSR J1023+0038 and PSR J1227−4853. For the other systems, we set limits on potential transitions in their measured gamma-ray light curves.

Authors:
; ; ;  [1]; ;  [2];  [3]
  1. Institute of Space Sciences (IEEC-CSIC), Campus UAB, Carrer de Magrans s/n, E-08193 Barcelona (Spain)
  2. Key Laboratory for Particle Astrophysics, Institute of High Energy Physics, Chinese Academy of Sciences, 19B Yuquan Road, Beijing 100049 (China)
  3. INAF-Osservatorio Astronomico di Roma, via di Frascati 33, I-00040 Monte Porzio Catone, Roma (Italy)
Publication Date:
OSTI Identifier:
22663847
Resource Type:
Journal Article
Resource Relation:
Journal Name: Astrophysical Journal; Journal Volume: 836; Journal Issue: 1; Other Information: Country of input: International Atomic Energy Agency (IAEA)
Country of Publication:
United States
Language:
English
Subject:
79 ASTROPHYSICS, COSMOLOGY AND ASTRONOMY; GAMMA RADIATION; GEV RANGE; PULSARS; STARS; TELESCOPES; VISIBLE RADIATION

Citation Formats

Torres, Diego F., Li, Jian, Rea, Nanda, Wilhelmi, Emma de Oña, Ji, Long, Zhang, Shu, and Papitto, Alessandro. A Search for Transitions between States in Redbacks and Black Widows Using Seven Years of Fermi -LAT Observations. United States: N. p., 2017. Web. doi:10.3847/1538-4357/836/1/68.
Torres, Diego F., Li, Jian, Rea, Nanda, Wilhelmi, Emma de Oña, Ji, Long, Zhang, Shu, & Papitto, Alessandro. A Search for Transitions between States in Redbacks and Black Widows Using Seven Years of Fermi -LAT Observations. United States. doi:10.3847/1538-4357/836/1/68.
Torres, Diego F., Li, Jian, Rea, Nanda, Wilhelmi, Emma de Oña, Ji, Long, Zhang, Shu, and Papitto, Alessandro. Fri . "A Search for Transitions between States in Redbacks and Black Widows Using Seven Years of Fermi -LAT Observations". United States. doi:10.3847/1538-4357/836/1/68.
@article{osti_22663847,
title = {A Search for Transitions between States in Redbacks and Black Widows Using Seven Years of Fermi -LAT Observations},
author = {Torres, Diego F. and Li, Jian and Rea, Nanda and Wilhelmi, Emma de Oña and Ji, Long and Zhang, Shu and Papitto, Alessandro},
abstractNote = {Considering about seven years of Fermi -Large Area Telescope (LAT) data, we present a systematic search for variability that is possibly related to transitions between states in redbacks and black widow systems. The transitions are characterized by sudden and significant changes in the gamma-ray flux that persist on a timescale that is much larger than the orbital period. This phenomenology was already detected in the case of two redback systems, PSR J1023+0038 and PSR J1227−4853, which we present here. We show the existence of only one transition for each of these systems over the past seven years. We determine their spectra, establishing high-energy cutoffs at a few GeV for the high gamma-ray state of PSR J1023+0038, and for both states of PSR J1227−4853. The surveying capability of the Fermi -LAT allows further study of whether similar phenomenology has occurred in other sources. Although we have not found any evidence of a state transition for most of the studied pulsars, we note two black-widow systems, PSR J2234+0944 and PSR J1446−4701, whose apparent variabilities are reminiscent of the transitions in PSR J1023+0038 and PSR J1227−4853. For the other systems, we set limits on potential transitions in their measured gamma-ray light curves.},
doi = {10.3847/1538-4357/836/1/68},
journal = {Astrophysical Journal},
number = 1,
volume = 836,
place = {United States},
year = {Fri Feb 10 00:00:00 EST 2017},
month = {Fri Feb 10 00:00:00 EST 2017}
}