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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"

45431 results found.

  1. Fermi GRB 241118A: Global MASTER-Net observations report
  2. GRB 241118A: Fermi GBM Final Real-time Localization
  3. Updates to IceCube realtime alert system for muon tracks
  4. GRB 241117A: SVOM/GRM observation of a short burst with extended emission
  5. GRB 241117A: Fermi GBM Detection
  6. Fermi GRB 241117B: Global MASTER-Net observations report
  7. GRB 241117B: Fermi GBM Final Real-time Localization
  8. IceCube-Cascade 241116A: Upper limits from a search for additional neutrino events in IceCube
  9. LIGO/Virgo/KAGRA S241116cq: Updated Sky localization
  10. GRB 241115B: Swift/BAT-GUANO localization skymap of a long burst
  11. Fermi GRB 241117A: Global MASTER-Net observations report
  12. GRB 241117A: Fermi GBM Final Real-time Localization
  13. GRB 241115C: Fermi GBM Observation
  14. GRB 241115A: Swift-XRT afterglow detection
  15. LIGO/Virgo/KAGRA S241116cq: Identification of a GW compact binary merger candidate
  16. EP241115a/GRB 241115D: Optical upper limits with Kinder observations
  17. GRB 241115A: Mephisto upper limits
  18. GRB 241113B: Mephisto upper limits
  19. EP241115a/GRB 241115D: Swift/XRT follow-up observation
  20. GRB 241115D / EP 241115a: SVOM/GRM observation
  21. The EP-WXT trigger 01709120856 is likely a flaring star
  22. EP241113a: Swift XRT weak detection
  23. GRB 241115A: Fermi GBM Observation
  24. GRB 241115A: LCOGT Optical Upper Limits
  25. GRB 241115C: Swift/BAT-GUANO localization skymap of a burst
  26. Fermi GRB 241115B: Global MASTER-Net observations report
  27. LIGO/Virgo/KAGRA S241114bi: Updated Sky localization and EM Bright Classification
  28. EP241115a: Global MASTER-Net observations report
  29. GRB 241115B: Fermi GBM Final Real-time Localization
  30. LIGO/Virgo/KAGRA S241113p: Updated Sky localization
  31. EP241115a: EP detection of a fast X-ray transient
  32. EP241113a: No Detection in Fermi-GBM Observations
  33. Swift GRB 241115A: Global MASTER-Net observations report
  34. Fermi GRB 241115A: Global MASTER-Net observations report
  35. GRB 241115A: Swift detection of a burst
  36. GRB 241115A: Fermi GBM Final Real-time Localization
  37. EP 241113a: LBT possible optical counterpart
  38. GRB 241113B: KAIT Optical Afterglow Candidate
  39. LIGO/Virgo/KAGRA S241114bi: Upper limits from Fermi-GBM Observations
  40. LIGO/Virgo/KAGRA S241114bi: Coverage and upper limits from MAXI/GSC observations
  41. GRB 241113A: Swift-BAT refined analysis
  42. LIGO/Virgo/KAGRA S241114bi: Identification of a GW compact binary merger candidate
  43. GRB 241113A: PRIME near-infrared upper limits
  44. Fermi GRB 241114A: Global MASTER-Net observations report
  45. EP241113a: Global MASTER-Net observations report
  46. GRB 241114A: Fermi GBM Final Real-time Localization
  47. GRB 241113B: J-band upper limit from WINTER
  48. GRB 241113A: J-band observations with WINTER
  49. EP241113a : J-band observations with WINTER
  50. GRB 241030A: LCO optical observation
  51. GRB 241113B: Swift-XRT observations
  52. IceCube-241113A: Upper limits from a search for additional neutrino events in IceCube
  53. GRB 241113A: 1.6m Mephisto and 50cm array optical upper limits
  54. GRB 241113A: KAIT optical observations
  55. EP241113b: Global MASTER-Net observations report
  56. EP241113b/GRB 241113B: EP detection of GRB 241113B
  57. Fermi-LAT gamma-ray observations of IceCube-241113A
  58. GRB 241113B: SVOM/GRM observation
  59. EP241113a: EP on-board trigger and autonomous follow-up observation
  60. LIGO/Virgo/KAGRA S241114y: Identification of a GW compact binary merger candidate
  61. GRB 241113A: Swift-XRT refined Analysis
  62. EP241107a: SOAR upper limits
  63. GRB 241113A: Swift/UVOT Detection
  64. GRB 241113A: REM detection of the optical/NIR afterglow
  65. Konus-Wind detection of GRB 241107A (short/hard)
  66. LIGO/Virgo/KAGRA S241113p: Identification of a GW compact binary merger candidate
  67. Fermi Gamma-ray Burst Monitor trigger 753166198/241113201 is not a GRB
  68. GRB 241113B: Swift ToO observations
  69. GRB 241113A: LCO optical observations
  70. IceCube-241113A - IceCube observation of a high-energy neutrino candidate track-like event
  71. GRB 241112B: GMG Optical Upper Limit
  72. GRB 241113A: Enhanced Swift-XRT position
  73. GRB241113A: LCOGT (40-cm) optical counterpart detection
  74. GRB 241113B : detection of a long GRB by SVOM/ECLAIRs
  75. GRB 241113A: MASTER010615.66-224018.2 optical counterpart detection
  76. GRB 241113A: Swift detection of a burst with an optical counterpart
  77. Swift GRB241113.33: Global MASTER-Net observations report
  78. SVOM/GRM detection of a short burst from SGR 1E1841-045
  79. Fermi trigger No 753166198: Global MASTER-Net observations report
  80. LIGO/Virgo/KAGRA S241111bn: Updated Sky localization
  81. GRB 241105A: ATCA Radio Upper Limits
  82. GRB 241112B: AbAO optical upper limit
  83. GRB 241107A: GROWTH-India telescope optical upper limit
  84. IceCube Alert 241113.02: Global MASTER-Net observations report
  85. Fermi GRB 241112A: Global MASTER-Net observations report
  86. Fermi-GBM Sub-Threshold Detection of GRB 241112B
  87. GRB 241112B: Optical afterglow detection confirmation in revisiting the Mephisto data
  88. GRB 241112B: Swift-XRT afterglow detection
  89. GRB 241112B: LCO optical detection of the SVOM/VT candidate
  90. GRB 241112B: SVOM/GRM observation
  91. GRB 241112B: SVOM/VT afterglow detection
  92. Fermi Gamma-ray Burst Monitor trigger 752995908/241111230 (GRB 241111A) is not a GRB
  93. GRB 241107A: Swift/BAT candidate arcminute localization of a short burst
  94. GRB 241112B: Mephisto optical upper limits
  95. GRB 241112B: GOTO optical upper limits
  96. GRB 241112B: Swift ToO observations
  97. GRB 241112B : detection of a long GRB by SVOM/ECLAIRs
  98. GRB 241107A: INTEGRAL IBIS localization
  99. EP241107a: EP-FXT follow-up observations
  100. GRB 241112A: Fermi GBM Final Real-time Localization

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