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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"

3872 results found.

  1. Fermi Gamma-ray Burst Monitor trigger 743953682/240729575 is not a GRB
  2. Fermi GRB 240727A: Global MASTER-Net observations report
  3. GRB 240718A: GRBAlpha detection
  4. GRB 240627A: GRBAlpha detection
  5. Fermi GRB 240726A: Global MASTER-Net observations report
  6. Fermi trigger No 743345551: Global MASTER-Net observations report
  7. Fermi trigger No 743219692: Global MASTER-Net observations report
  8. Swift GRB240720.02: Global MASTER-Net observations report
  9. Konus-Wind detection of GRB 240718A
  10. Fermi GRB 240718A: Global MASTER-Net observations report
  11. GRB 240718A: Fermi GBM Observation
  12. IceCube-Cascade 240714A: TRT optical observations on the EP/FXT positions
  13. GRB 240718A: Fermi-LAT Detection
  14. GRB 240718A: SVOM/GRM observation
  15. GRB 240718A: BALROG localization (Fermi Trigger 742976945 / GRB 240718270)
  16. GRB 240718A: Fermi GBM Final Real-time Localization
  17. IPN triangulation of GRB 240715A (short)
  18. JinShan confirmation of the EP-WXT source triggered on July 14th due to a flaring star
  19. GRB 240712A: Swift detection of a burst
  20. Fermi trigger No 742317942: Global MASTER-Net observations report
  21. LIGO/Virgo S240615dg: Swift XRT observations, 28 futher X-ray sources
  22. LIGO/Virgo/KAGRA S240629by: Coverage and upper limits from MAXI/GSC observations
  23. Fermi trigger No 741356809: Global MASTER-Net observations report
  24. Fermi GRB 240629A: Global MASTER-Net observations report
  25. Fermi Gamma-ray Burst Monitor trigger 741362867/240629589 is not a GRB
  26. GRB 240629A: BALROG localization (Fermi Trigger 741372837 / GRB 240629704)
  27. GRB 240629A: Fermi GBM Final Real-time Localization
  28. Fermi Gamma-ray Burst Monitor trigger 741356809/240629519 is not a GRB
  29. LIGO/Virgo/KAGRA S240629by: Identification of a GW compact binary merger candidate
  30. Konus-Wind detection of GRB 240619A
  31. Fermi trigger No 740949590: Global MASTER-Net observations report
  32. GRB 240529A: JinShan optical observations
  33. Fermi trigger No 740474239: Global MASTER-Net observations report
  34. LIGO/Virgo S240615dg: Swift XRT observations, 39 X-ray sources
  35. Fermi trigger No 740430582: Global MASTER-Net observations report
  36. Fermi GRB 240616A: Global MASTER-Net observations report
  37. Fermi trigger No 740166710: Global MASTER-Net observations report
  38. GRB 240612A: GRBAlpha detection
  39. Fermi GRB 240611A: Global MASTER-Net observations report
  40. GRB 240529A : MITSuME Akeno optical afterglow detection
  41. Fermi GRB 240604A: Global MASTER-Net observations report
  42. Fermi GRB 240605A: Global MASTER-Net observations report
  43. GRB 240529A: MASTER prompt OT detection
  44. Fermi GRB 240602A: Global MASTER-Net observations report
  45. The EP-WXT source triggered on June 1st is likely a flaring star
  46. GRB 240529A: AKO Optical Afterglow Follow-Up Observations
  47. GRB 240529A: optical photometry from Konkoly
  48. GRB 240529A: GROWTH-India optical follow-up
  49. GRB 240529A: AKO Optical Afterglow Detection
  50. GRB 240529A: J-band detections with WINTER
  51. GRB 240529A: Skynet Optical Observations
  52. LIGO/Virgo S240527fv: GRANDMA/FRAM-Auger Optical Observations
  53. GRB240529A: BOOTES-6/DPRT optical detection
  54. GRB 240529A: NOT optical observations
  55. GRB 240529A: AstroSat CZTI detection
  56. Swift GRB240529.12: Global MASTER-Net observations report
  57. Fermi GRB 240527A: Global MASTER-Net observations report
  58. LAT GRB240527.59: Global MASTER-Net observations report
  59. Fermi trigger No 738348224: Global MASTER-Net observations report
  60. Fermi trigger No 738330463: Global MASTER-Net observations report
  61. Fermi trigger No 737996942: Global MASTER-Net observations report
  62. GRB 240516B: AstroSat CZTI detection
  63. GRB 240516A: Swift-BAT refined analysis
  64. GRB 240502C: Zeiss-1000 at Koshka observations of GOTO24bao optical counterpart candidate
  65. GRB 240516A: GOTO optical upper limit
  66. GRB 240516A: Swift detection of a burst
  67. Fermi GRB 240514B: Global MASTER-Net observations report
  68. LAT GRB240513.31: Global MASTER-Net observations report
  69. Fermi GRB 240513B: Global MASTER-Net observations report
  70. Fermi trigger No 737277727: Global MASTER-Net observations report
  71. Fermi trigger No 737247400: Global MASTER-Net observations report
  72. Fermi trigger No 737168073: Global MASTER-Net observations report
  73. Fermi trigger No 737173236: Global MASTER-Net observations report
  74. Fermi trigger No 737105243: Global MASTER-Net observations report
  75. Fermi trigger No 737152719: Global MASTER-Net observations report
  76. Fermi trigger No 737111207: Global MASTER-Net observations report
  77. EP240506a: CrAO ZTSH optical upper limit
  78. EP240506a: Optical upper limit with Kinder observations
  79. IPN triangulation of GRB 240504A
  80. GRB 240502A: 1.3m DFOT Optical upper limit
  81. GRB 240502C: Zeiss-1000 at Koshka observatory observations of GOTO optical counterpart candidates
  82. GRB 240415A 1.3m DFOT Optical upper limit
  83. Fermi GRB 240502B: Global MASTER-Net observations report
  84. Fermi GRB 240502A: Global MASTER-Net observations report
  85. Fermi trigger No 736197684: Global MASTER-Net observations report
  86. LIGO/Virgo/KAGRA S240501an: Identification of a GW compact binary merger candidate
  87. GRB 240429A: Fermi GBM Final Real-time Localization
  88. LIGO/Virgo/KAGRA S240428dr: Identification of a GW compact binary merger candidate
  89. LIGO/Virgo S240422ed: Swift XRT observation of EP240426a
  90. LIGO/Virgo/KAGRA S240422ed: NOT optical observations of EP240426a
  91. LIGO/Virgo/KAGRA S240422ed: Continued Magellan Observations
  92. LIGO/Virgo/KAGRA S240422ed: EP-FXT detection of a candidate counterpart EP240426a
  93. S240422ed: BlackGEM/MeerLICHT transient detection AT2024hgl/MLTJ080628.10-250116.4
  94. LIGO/Virgo/KAGRA S240422ed: Further near-infrared observations with Subaru/MOIRCS by J-GEM Collaboration
  95. LIGO/Virgo/KAGRA S240422ed: X-ray Upper Limits from EP-FXT for the Potential Electromagnetic Counterparts Reported by Swift and DECam
  96. LIGO/Virgo/KAGRA S240422ed: No significant candidates in GRANDMA/FRAM Observations
  97. LIGO/Virgo/KAGRA S240422ed: Subaru/MOIRCS near-infrared observations by J-GEM Collaboration
  98. LIGO/Virgo/KAGRA S240422ed: GW-MMADS DECam upper limits on the Swift/XRT source S240422ed_X61
  99. LIGO/Virgo/KAGRA S240422ed: AstroSat CZTI non-detection and upper limits
  100. Fermi trigger No 735470374: Global MASTER-Net observations report

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