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GCN Circulars

GCN Circulars are rapid astronomical bulletins submitted by and distributed to community members worldwide. They are used to share discoveries, observations, quantitative near-term predictions, requests for follow-up observations, or future observing plans related to high-energy, multi-messenger, and variable or transient astrophysical events. See the documentation for help with subscribing to or submitting Circulars.

Search for Circulars by submitter, subject, or body text (e.g. 'Fermi GRB').
To navigate to a specific circular, enter the associated Circular ID (e.g. 'gcn123', 'Circular 123', or '123').
Advanced Search

To narrow the search results, use advanced search syntax. This allows for specifying which circular field to search (submitter, subject, and/or body). For additional information, refer to the advanced search documentation.

Advanced Search Examples (click to copy):

subject:"Swift"
body:"GRB"
submitter:"Judith Racusin"

2974 results found.

  1. GRB 200216B: Swift-BAT refined analysis
  2. LIGO/Virgo S200213t : No significant candidates in FRAM - OAJ - TAROT - GRANDMA observations
  3. LIGO/Virgo S200213t: No candidates found in J-GEM follow-up observations
  4. LIGO/Virgo S200213t: No counterpart candidates in KAIT observations
  5. LIGO/Virgo S200213t: No Counterparts in DDOTI/OAN Optical Observations
  6. LIGO/Virgo S200208q : No significant candidates in TAROT - FRAM - GRANDMA observations
  7. LIGO/Virgo S200208q: no counterpart candidate in SVOM/C-GFT observations
  8. LIGO/Virgo S200208q: No counterpart candidates in KAIT observations
  9. Fermi trigger No 602817262: Global MASTER-Net observations report
  10. GRB 200205B: Swift-BAT refined analysis
  11. Swift J0840.7-3516 (AKA GRB 200205A): Swift-BAT refined analysis
  12. ZTF20aajnksq: Gemini-North r-band photometry
  13. GRB 200201A: Fermi GBM Final Real-time Localization
  14. IPN triangulation of GRB 200130B
  15. LIGO/Virgo S200128d: no counterpart candidate in SVOM/GWAC observations
  16. LIGO/Virgo S200128d : No significant candidates in FRAM - TAROT - GRANDMA observations
  17. GRB 200130A: Fermi GBM Final Real-time Localization
  18. LIGO/Virgo S200128d: No counterpart candidates in KAIT observations
  19. Fermi-LAT-ANTARES coincidence
  20. Fermi trigger No 601729856: Global MASTER-Net observations report
  21. Fermi trigger No 601677816: Global MASTER-Net observations report
  22. LIGO/Virgo S200114f : No significant candidates in TAROT - FRAM - GRANDMA observations
  23. LIGO/Virgo S200115j : No significant candidates in TAROT - FRAM - GRANDMA observations
  24. LIGO/Virgo S200105ae: More candidates from the Zwicky Transient Facility
  25. IceCube Alert 200117.46: Global MASTER-Net observations report
  26. LIGO/Virgo S200115j: Swift-XRT sources
  27. LIGO/Virgo S200114f: ZTF Forced Photometry of the Swift Source S200114f_X2
  28. LIGO/Virgo S200112r : No significant candidates in TAROT - FRAM - GRANDMA observations.
  29. LIGO/Virgo S200115j: no counterpart candidate in SVOM/GWAC observations
  30. Baksan Neutrino Observatory Alert 200116.22: Global MASTER-Net observations report
  31. GRB 200115A: Swift-BAT refined analysis
  32. Swift GRB200115.49: Global MASTER-Net observations report
  33. LIGO/Virgo S200114f: No counterpart candidates in INTEGRAL SPI-ACS and IBIS prompt observation
  34. GRB 200109A: Fermi GBM observation
  35. LIGO/Virgo S200105ae : No significant candidates in TAROT - FRAM - GRANDMA observations.
  36. Fermi trigger No 600227156: Global MASTER-Net observations report
  37. IceCube-200107A: No counterpart candidates in INTEGRAL SPI-ACS prompt observation
  38. LIGO/Virgo S200105ae: Global MASTER-Net observations report
  39. IPN triangulation of GRB 200101A
  40. IceCube-191231A: No significant detection in HAWC
  41. LIGO/Virgo S191216ap: Two candidate counterparts from UKIRT/WFCAM z-band observations
  42. GRB 191227A: MITSuME Akeno optical upper limits
  43. LIGO/Virgo S191222n : No significant candidates in FRAM-TAROT-GRANDMA observations
  44. LIGO/Virgo S191222n: no counterpart candidate in SVOM/GWAC observations
  45. LIGO/Virgo S191213g : No significant candidates found in GRANDMA citizen science observations
  46. LIGO/Virgo S191216ap: VLA/JAGWAR radio monitoring of the 1-sigma HAWC region
  47. LIGO/Virgo S191216ap : No significant candidates in FRAM-TAROT-GRANDMA observations
  48. Fermi trigger No 598543714: Global MASTER-Net observations report
  49. Swift GRB191220.56: Global MASTER-Net observations report
  50. LIGO/Virgo S191216ap, Swift XRT observations: 16 X-ray sources in the HAWC error region search
  51. LIGO/Virgo S191213g: No counterpart candidate in the NOWT observations
  52. LIGO/Virgo S191216ap: No candidates found in CHES observations of HAWC error region
  53. LIGO/Virgo S191216ap: Nanshan follow-up observations
  54. LIGO/Virgo S191213g: No candidates found in J-GEM follow-up observations
  55. LIGO/Virgo S191215w : No significant candidates in TAROT - FRAM - GRANDMA observations.
  56. IceCube-191215A: No counterpart candidates in INTEGRAL SPI-ACS prompt observation
  57. LIGO/Virgo S191213g: No neutrino candidates at Pierre Auger Observatory
  58. LIGO/Virgo S191213ai: Global MASTER-Net observations report
  59. LIGO/Virgo S191205ah: no counterpart candidate in SVOM/GWAC observations
  60. LIGO/Virgo S191205ah : No significant candidates in FRAM - TAROT – GRANDMA observations
  61. GRB 191203A: Insight-HXMT/HE detection
  62. LIGO/Virgo S191129u : No significant candidates in FRAM-TAROT-GRANDMA observations.
  63. LIGO/Virgo S191204r: No significant candidates in FRAM-TAROT-GRANDMA observations.
  64. LIGO/Virgo S191205ah: Global MASTER-Net observations report
  65. IceCube Alert 191204.95: Global MASTER-Net observations report
  66. GRB 191203A: Fermi GBM Final Real-time Localization
  67. Fermi trigger No 596786686: Global MASTER-Net observations report
  68. Fermi trigger No 596690552: Global MASTER-Net observations report
  69. Fermi trigger No 596387570: Global MASTER-Net observations report
  70. Baksan Neutrino Observatory Alert 191124.13: Global MASTER-Net observations report
  71. LIGO/Virgo S191124be: Global MASTER-Net observations report
  72. GRB 191122A: Swift-BAT refined analysis
  73. GRB 191122A: CHES Optical Observations
  74. LIGO/Virgo S191109d: No significant candidates in FRAM-TAROT-GRANDMA observations
  75. LIGO/Virgo S191105e: No significant candidates in FRAM-TAROT-GRANDMA observations
  76. GRB 191106A: Swift-XRT refined Analysis
  77. Fermi trigger No 594592184: Global MASTER-Net observations report
  78. Swift GRB191105.01: Global MASTER-Net observations report
  79. Swift GRB191105.01: Global MASTER-Net OT detection
  80. SGR 1935+2154: Swift-BAT refined analysis
  81. Fermi trigger No 594563923: Global MASTER-Net observations report
  82. GRB 191031A: Fermi GBM detection
  83. IPN triangulation of GRB 191027A
  84. Fermi trigger No 593176520: Global MASTER-Net observations report
  85. Swift GRB191016.17: Global MASTER-Net observations report
  86. Fermi trigger No 592818648: Global MASTER-Net observations report
  87. ANTARES 191011A: AMON + ANTARES Identification of a High-Energy Neutrino + Fermi LAT Coincidence
  88. Fermi trigger No 592211224: Global MASTER-Net observations report
  89. Konus-Wind observation of GRB 191004B
  90. Konus-Wind observation of GRB 191004A
  91. LIGO/Virgo S190930s: no counterpart candidate in the SVOM/GWAC observations
  92. Swift GRB191004.9: Global MASTER-Net OT detection
  93. LIGO/Virgo S190930s: Upper limits from Insight-HXMT/HE observations
  94. LIGO/Virgo S190930s: No counterpart candidates in KAIT observations
  95. Fermi trigger No 591604915: Global MASTER-Net observations report
  96. Konus-Wind observation of GRB 190928A
  97. LIGO/Virgo S190923y: No significant candidates in TAROT-GRANDMA observations
  98. LIGO/Virgo S190924h: No counterpart candidates in INTEGRAL SPI-ACS and IBIS prompt observation
  99. Baksan Neutrino Observatory Alert 190920.65: Global MASTER-Net observations report
  100. Integral GRB190919.99: Global MASTER-Net observations report

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