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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').
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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"

39155 results found.

  1. EP trigger ID 01709065118: Keck/LRIS spectroscopic observations
  2. EP-WXT trigger 01709018832: Lick/Kast spectroscopy with the 3 m Shane telescope
  3. GRB 241120A: Mondy and AbAO optical observations
  4. EP trigger ID 01709122294: the X-ray transient is likely a stellar flare event
  5. EP241119a: GIT optical upper limits
  6. GRB 241113A: Possible ATCA Radio detection
  7. GRB 241120A: Fermi GBM Observation
  8. GRB 241114B: Insight-HXMT/HE detection
  9. Integral GRB241120.25: Global MASTER-Net observations report
  10. EP241119a: Global MASTER-Net observations report
  11. GRB241120A: a long GRB detected by INTEGRAL
  12. GRB 241120A: Fermi GBM Final Real-time Localization
  13. GRB 241115A: CALET Gamma-Ray Burst Monitor detection
  14. GRB 241112B: Mephisto further optical observations
  15. GRB 241119A: Fermi GBM Final Real-time Localization
  16. GRB 241030A: J-band observations
  17. GRB 241115a: PRIME near-infrared upper limits
  18. GRB 241117A: Swift/BAT-GUANO localization skymap of a burst
  19. LIGO/Virgo/KAGRA S241116cq: Upper limits from Swift/BAT-GUANO
  20. GRB 241115B: Fermi GBM Observation
  21. Fermi GRB 241118A: Global MASTER-Net observations report
  22. GRB 241118A: Fermi GBM Final Real-time Localization
  23. GRB 241117A: SVOM/GRM observation of a short burst with extended emission
  24. GRB 241117A: Fermi GBM Detection
  25. Fermi GRB 241117B: Global MASTER-Net observations report
  26. GRB 241117B: Fermi GBM Final Real-time Localization
  27. GRB 241115B: Swift/BAT-GUANO localization skymap of a long burst
  28. Fermi GRB 241117A: Global MASTER-Net observations report
  29. GRB 241117A: Fermi GBM Final Real-time Localization
  30. GRB 241115C: Fermi GBM Observation
  31. GRB 241115A: Swift-XRT afterglow detection
  32. EP241115a/GRB 241115D: Optical upper limits with Kinder observations
  33. GRB 241115A: Mephisto upper limits
  34. GRB 241113B: Mephisto upper limits
  35. EP241115a/GRB 241115D: Swift/XRT follow-up observation
  36. GRB 241115D / EP 241115a: SVOM/GRM observation
  37. GRB 241115A: Fermi GBM Observation
  38. GRB 241115A: LCOGT Optical Upper Limits
  39. GRB 241115C: Swift/BAT-GUANO localization skymap of a burst
  40. Fermi GRB 241115B: Global MASTER-Net observations report
  41. EP241115a: Global MASTER-Net observations report
  42. GRB 241115B: Fermi GBM Final Real-time Localization
  43. EP241113a: No Detection in Fermi-GBM Observations
  44. Swift GRB 241115A: Global MASTER-Net observations report
  45. Fermi GRB 241115A: Global MASTER-Net observations report
  46. GRB 241115A: Swift detection of a burst
  47. GRB 241115A: Fermi GBM Final Real-time Localization
  48. EP 241113a: LBT possible optical counterpart
  49. GRB 241113B: KAIT Optical Afterglow Candidate
  50. LIGO/Virgo/KAGRA S241114bi: Upper limits from Fermi-GBM Observations
  51. GRB 241113A: Swift-BAT refined analysis
  52. GRB 241113A: PRIME near-infrared upper limits
  53. Fermi GRB 241114A: Global MASTER-Net observations report
  54. EP241113a: Global MASTER-Net observations report
  55. GRB 241114A: Fermi GBM Final Real-time Localization
  56. GRB 241113B: J-band upper limit from WINTER
  57. GRB 241113A: J-band observations with WINTER
  58. GRB 241030A: LCO optical observation
  59. GRB 241113B: Swift-XRT observations
  60. GRB 241113A: 1.6m Mephisto and 50cm array optical upper limits
  61. GRB 241113A: KAIT optical observations
  62. EP241113b: Global MASTER-Net observations report
  63. EP241113b/GRB 241113B: EP detection of GRB 241113B
  64. GRB 241113B: SVOM/GRM observation
  65. GRB 241113A: Swift-XRT refined Analysis
  66. GRB 241113A: Swift/UVOT Detection
  67. GRB 241113A: REM detection of the optical/NIR afterglow
  68. Konus-Wind detection of GRB 241107A (short/hard)
  69. Fermi Gamma-ray Burst Monitor trigger 753166198/241113201 is not a GRB
  70. GRB 241113B: Swift ToO observations
  71. GRB 241113A: LCO optical observations
  72. IceCube-241113A - IceCube observation of a high-energy neutrino candidate track-like event
  73. GRB 241112B: GMG Optical Upper Limit
  74. GRB 241113A: Enhanced Swift-XRT position
  75. GRB241113A: LCOGT (40-cm) optical counterpart detection
  76. GRB 241113B : detection of a long GRB by SVOM/ECLAIRs
  77. GRB 241113A: MASTER010615.66-224018.2 optical counterpart detection
  78. GRB 241113A: Swift detection of a burst with an optical counterpart
  79. Swift GRB241113.33: Global MASTER-Net observations report
  80. SVOM/GRM detection of a short burst from SGR 1E1841-045
  81. Fermi trigger No 753166198: Global MASTER-Net observations report
  82. GRB 241105A: ATCA Radio Upper Limits
  83. GRB 241112B: AbAO optical upper limit
  84. GRB 241107A: GROWTH-India telescope optical upper limit
  85. IceCube Alert 241113.02: Global MASTER-Net observations report
  86. Fermi GRB 241112A: Global MASTER-Net observations report
  87. Fermi-GBM Sub-Threshold Detection of GRB 241112B
  88. GRB 241112B: Optical afterglow detection confirmation in revisiting the Mephisto data
  89. GRB 241112B: Swift-XRT afterglow detection
  90. GRB 241112B: LCO optical detection of the SVOM/VT candidate
  91. GRB 241112B: SVOM/GRM observation
  92. GRB 241112B: SVOM/VT afterglow detection
  93. Fermi Gamma-ray Burst Monitor trigger 752995908/241111230 (GRB 241111A) is not a GRB
  94. GRB 241107A: Swift/BAT candidate arcminute localization of a short burst
  95. GRB 241112B: Mephisto optical upper limits
  96. GRB 241112B: GOTO optical upper limits
  97. GRB 241112B: Swift ToO observations
  98. GRB 241112B : detection of a long GRB by SVOM/ECLAIRs
  99. GRB 241107A: INTEGRAL IBIS localization
  100. GRB 241112A: Fermi GBM Final Real-time Localization

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