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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"

3797 results found.

  1. MAXI GRB200205.29: Global MASTER-Net observations report
  2. ZTF20aajnksq: Gemini-North r-band photometry
  3. GRB 200201A: Fermi GBM Final Real-time Localization
  4. IPN triangulation of GRB 200130B
  5. LIGO/Virgo S200128d: no counterpart candidate in SVOM/GWAC observations
  6. LIGO/Virgo S200128d : No significant candidates in FRAM - TAROT - GRANDMA observations
  7. GRB 200130A: Fermi GBM Final Real-time Localization
  8. LIGO/Virgo S200129m: Coverage and upper limits from MAXI/GSC observations
  9. LIGO/Virgo S200128d: No counterpart candidates in KAIT observations
  10. Fermi-LAT-ANTARES coincidence
  11. LIGO/Virgo S200128d: Coverage and upper limits from MAXI/GSC observations
  12. Fermi trigger No 601729856: Global MASTER-Net observations report
  13. Fermi trigger No 601677816: Global MASTER-Net observations report
  14. LIGO/Virgo S200114f : No significant candidates in TAROT - FRAM - GRANDMA observations
  15. LIGO/Virgo S200115j : No significant candidates in TAROT - FRAM - GRANDMA observations
  16. LIGO/Virgo S200105ae: More candidates from the Zwicky Transient Facility
  17. IceCube Alert 200117.46: Global MASTER-Net observations report
  18. LIGO/Virgo S200115j: Swift-XRT sources
  19. LIGO/Virgo S200114f: ZTF Forced Photometry of the Swift Source S200114f_X2
  20. LIGO/Virgo S200112r : No significant candidates in TAROT - FRAM - GRANDMA observations.
  21. LIGO/Virgo S200115j: no counterpart candidate in SVOM/GWAC observations
  22. Baksan Neutrino Observatory Alert 200116.22: Global MASTER-Net observations report
  23. GRB 200115A: Swift-BAT refined analysis
  24. Swift GRB200115.49: Global MASTER-Net observations report
  25. LIGO/Virgo S200115j: Coverage and upper limits from MAXI/GSC observations
  26. LIGO/Virgo S200114f: No counterpart candidates in INTEGRAL SPI-ACS and IBIS prompt observation
  27. LIGO/Virgo S200114f: Coverage and upper limits from MAXI/GSC observations
  28. LIGO/Virgo S200112r: Coverage and upper limits from MAXI/GSC observations
  29. GRB 200109A: Fermi GBM observation
  30. LIGO/Virgo S200105ae : No significant candidates in TAROT - FRAM - GRANDMA observations.
  31. Fermi trigger No 600227156: Global MASTER-Net observations report
  32. IceCube-200107A: No counterpart candidates in INTEGRAL SPI-ACS prompt observation
  33. LIGO/Virgo S200105ae: Coverage and upper limits from MAXI/GSC observations
  34. LIGO/Virgo S200105ae: Global MASTER-Net observations report
  35. GRB 200105A: MAXI/GSC detection
  36. IPN triangulation of GRB 200101A
  37. IceCube-191231A: No significant detection in HAWC
  38. LIGO/Virgo S191216ap: Two candidate counterparts from UKIRT/WFCAM z-band observations
  39. GRB 191227A: MITSuME Akeno optical upper limits
  40. LIGO/Virgo S191222n : No significant candidates in FRAM-TAROT-GRANDMA observations
  41. LIGO/Virgo S191222n: no counterpart candidate in SVOM/GWAC observations
  42. LIGO/Virgo S191213g : No significant candidates found in GRANDMA citizen science observations
  43. LIGO/Virgo S191222n: Coverage and upper limits from MAXI/GSC observations
  44. LIGO/Virgo S191216ap: VLA/JAGWAR radio monitoring of the 1-sigma HAWC region
  45. LIGO/Virgo S191216ap : No significant candidates in FRAM-TAROT-GRANDMA observations
  46. Fermi trigger No 598543714: Global MASTER-Net observations report
  47. Swift GRB191220.56: Global MASTER-Net observations report
  48. LIGO/Virgo S191216ap, Swift XRT observations: 16 X-ray sources in the HAWC error region search
  49. LIGO/Virgo S191213g: No counterpart candidate in the NOWT observations
  50. LIGO/Virgo S191216ap: No candidates found in CHES observations of HAWC error region
  51. LIGO/Virgo S191216ap: Nanshan follow-up observations
  52. LIGO/Virgo S191213g: No candidates found in J-GEM follow-up observations
  53. LIGO/Virgo S191215w : No significant candidates in TAROT - FRAM - GRANDMA observations.
  54. LIGO/Virgo S191216ap: Coverage and upper limits from MAXI/GSC observations
  55. LIGO/Virgo S191215w: Coverage and upper limits from MAXI/GSC 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 S191213g: Coverage and upper limits from MAXI/GSC observations
  60. LIGO/Virgo S191205ah: no counterpart candidate in SVOM/GWAC observations
  61. LIGO/Virgo S191205ah : No significant candidates in FRAM - TAROT – GRANDMA observations
  62. GRB 191203A: Insight-HXMT/HE detection
  63. LIGO/Virgo S191129u : No significant candidates in FRAM-TAROT-GRANDMA observations.
  64. LIGO/Virgo S191204r: No significant candidates in FRAM-TAROT-GRANDMA observations.
  65. LIGO/Virgo S191205ah: Coverage and upper limits from MAXI/GSC observations
  66. LIGO/Virgo S191205ah: Global MASTER-Net observations report
  67. IceCube Alert 191204.95: Global MASTER-Net observations report
  68. LIGO/Virgo S191204r: Coverage and upper limits from MAXI/GSC observations
  69. GRB 191203A: Fermi GBM Final Real-time Localization
  70. Fermi trigger No 596786686: Global MASTER-Net observations report
  71. LIGO/Virgo S191129u: Coverage and upper limits from MAXI/GSC observations
  72. Fermi trigger No 596690552: Global MASTER-Net observations report
  73. Fermi trigger No 596387570: Global MASTER-Net observations report
  74. Baksan Neutrino Observatory Alert 191124.13: Global MASTER-Net observations report
  75. LIGO/Virgo S191124be: Global MASTER-Net observations report
  76. GRB 191122A: Swift-BAT refined analysis
  77. GRB 191122A: CHES Optical Observations
  78. LIGO/Virgo S191110af: Coverage and upper limits from MAXI/GSC observations
  79. LIGO/Virgo S191109d: No significant candidates in FRAM-TAROT-GRANDMA observations
  80. LIGO/Virgo S191105e: No significant candidates in FRAM-TAROT-GRANDMA observations
  81. LIGO/Virgo S191109d: Coverage and upper limits from MAXI/GSC observations
  82. LIGO/Virgo S191105e: Coverage and upper limits from MAXI/GSC observations
  83. GRB 191106A: Swift-XRT refined Analysis
  84. Fermi trigger No 594592184: Global MASTER-Net observations report
  85. Swift GRB191105.01: Global MASTER-Net observations report
  86. Swift GRB191105.01: Global MASTER-Net OT detection
  87. SGR 1935+2154: Swift-BAT refined analysis
  88. Fermi trigger No 594563923: Global MASTER-Net observations report
  89. GRB 191031A: Fermi GBM detection
  90. IPN triangulation of GRB 191027A
  91. Fermi trigger No 593176520: Global MASTER-Net observations report
  92. Swift GRB191016.17: Global MASTER-Net observations report
  93. Fermi trigger No 592818648: Global MASTER-Net observations report
  94. ANTARES 191011A: AMON + ANTARES Identification of a High-Energy Neutrino + Fermi LAT Coincidence
  95. Fermi trigger No 592211224: Global MASTER-Net observations report
  96. Konus-Wind observation of GRB 191004B
  97. Konus-Wind observation of GRB 191004A
  98. LIGO/Virgo S190930s: no counterpart candidate in the SVOM/GWAC observations
  99. Swift GRB191004.9: Global MASTER-Net OT detection
  100. LIGO/Virgo S190930s: Upper limits from Insight-HXMT/HE observations

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