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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"

2676 results found.

  1. Fermi trigger No 744761058: Global MASTER-Net observations report
  2. GRB 240807A: Fermi GBM Final Localization
  3. EP240807a: EP-WXT detection of a fast X-ray transient
  4. Fermi trigger No 744629911: Global MASTER-Net observations report
  5. Konus-Wind detection of GRB 240802A (EP240802a)
  6. Fermi trigger No 744544656: Global MASTER-Net observations report
  7. Fermi GRB 240805A: Global MASTER-Net observations report
  8. GRB 240802A: AstroSat CZTI detection of a long burst
  9. GRB 240801B: AstroSat CZTI detection of a bright long burst
  10. GRB 240730C: AstroSat CZTI detection of a long burst
  11. Fermi trigger No 744128417: Global MASTER-Net observations report
  12. GRB 240731A: AstroSat CZTI detection
  13. Fermi trigger No 743953682: Global MASTER-Net observations report
  14. Fermi GRB 240727A: Global MASTER-Net observations report
  15. GRB 240727C: AstroSat CZTI detection of a long burst
  16. GRB 240727B: AstroSat CZTI detection
  17. GRB 240726B: AstroSat CZTI detection of a short burst
  18. GRB 240726A: AstroSat CZTI detection of a short burst
  19. Fermi trigger No 743219692: Global MASTER-Net observations report
  20. IceCube Alert 240721.68: Global MASTER-Net observations report
  21. GRB 240720B: AstroSat CZTI detection of a short burst
  22. GRB 240720A: AstroSat CZTI detection
  23. Fermi GRB 240718A: Global MASTER-Net observations report
  24. GRB 240713B: AstroSat CZTI detection of a long burst
  25. LIGO/Virgo/KAGRA S240711cm: Coverage and upper limits from MAXI/GSC observations
  26. LIGO/Virgo S240615dg: Swift XRT observations, 28 futher X-ray sources
  27. EP240703a: Kinder optical follow-up observations
  28. EP240703a/GRB 240703A: TRT and JinShan decaying optical afterglow candidate
  29. Fermi GRB 240702A: Global MASTER-Net observations report
  30. Fermi trigger No 741448122: Global MASTER-Net observations report
  31. GRB 240629A: Fermi GBM Final Real-time Localization
  32. Fermi trigger No 741296200: Global MASTER-Net observations report
  33. GRB 240627A: AstroSat CZTI detection
  34. EP240625a: GRANDMA Optical Upper Limits
  35. EP240625a: NOT optical counterpart candidate
  36. Fermi trigger No 740949590: Global MASTER-Net observations report
  37. IPN triangulation of GRB 240615A (short)
  38. GRB 240619C: AstroSat CZTI detection
  39. Fermi trigger No 740474239: Global MASTER-Net observations report
  40. Fermi trigger No 740430582: Global MASTER-Net observations report
  41. LIGO/Virgo/KAGRA S240618ah: Identification of a GW compact binary merger candidate
  42. Fermi trigger No 740166710: Global MASTER-Net observations report
  43. Fermi GRB 240611A: Global MASTER-Net observations report
  44. GRB240529A: 3.6m TNG NIR detection 8d after the burst
  45. GRB 240607A: AstroSat CZTI detection of bright long burst
  46. Fermi trigger No 739373591: Global MASTER-Net observations report
  47. Fermi GRB 240604A: Global MASTER-Net observations report
  48. Fermi GRB 240605A: Global MASTER-Net observations report
  49. Fermi GRB 240603C: Global MASTER-Net observations report
  50. Fermi GRB 240602A: Global MASTER-Net observations report
  51. GRB 240531A: AstroSat CZTI detection of a short burst
  52. GRB 240529A: J-band detections with WINTER
  53. GRB 240529A: Skynet Optical Observations
  54. LIGO/Virgo S240527fv: GRANDMA/FRAM-Auger Optical Observations
  55. GRB 240529A: AstroSat CZTI detection
  56. LAT GRB240527.59: Global MASTER-Net observations report
  57. Fermi GRB 240527B: Global MASTER-Net observations report
  58. Fermi trigger No 738348224: Global MASTER-Net observations report
  59. Fermi trigger No 737996942: Global MASTER-Net observations report
  60. GRB 240516B: AstroSat CZTI detection
  61. GRB 240519A: AstroSat CZTI detection
  62. Fermi GRB 240517A: Global MASTER-Net observations report
  63. GRB 240516A: AstroSat CZTI detection
  64. MAXI GRB240514.78: Global MASTER-Net observations report
  65. GRB 240514D: AstroSat CZTI detection
  66. Fermi GRB 240514B: Global MASTER-Net observations report
  67. LAT GRB240513.31: Global MASTER-Net observations report
  68. Fermi trigger No 737277727: Global MASTER-Net observations report
  69. GRB 240513B: Fermi GBM Final Real-time Localization
  70. GRB 240513A: AstroSat CZTI detection
  71. Fermi trigger No 737168073: Global MASTER-Net observations report
  72. Fermi trigger No 737152719: Global MASTER-Net observations report
  73. Fermi trigger No 736733320: Global MASTER-Net observations report
  74. Fermi trigger No 736564880: Global MASTER-Net observations report
  75. GRB 240503A: AstroSat CZTI detection
  76. Fermi trigger No 736387941: Global MASTER-Net observations report
  77. Fermi trigger No 736379109: Global MASTER-Net observations report
  78. Fermi GRB 240502A: Global MASTER-Net observations report
  79. GRB 240502B: Fermi GBM Final Real-time Localization
  80. LIGO/Virgo/KAGRA S240422ed: GECKO/KMTNet Transient Candidates
  81. Fermi trigger No 736197684: Global MASTER-Net observations report
  82. GRB 240501B: AstroSat CZTI detection
  83. GRB 240408B: VZLUSAT-2 detection
  84. LIGO/Virgo/KAGRA S240422ed: ENGRAVE VLT/XShooter spectroscopy of the host galaxy of J-GEM24a
  85. GRB 240426A: AstroSat CZTI detection
  86. EP240426a: YAHPT optical upper limit
  87. LIGO/Virgo/KAGRA S240422ed: Continued Magellan Observations
  88. LIGO/Virgo/KAGRA S240422ed: Further near-infrared observations with Subaru/MOIRCS by J-GEM Collaboration
  89. GRB 240425A: Fermi GBM Final Real-time Localization
  90. LIGO/Virgo/KAGRA S240422ed: No significant candidates in GRANDMA/FRAM Observations
  91. LIGO/Virgo S240422ed: Swift-XRT detection of 3 possible counterparts
  92. LIGO/Virgo/KAGRA S240422ed: Continued Imaging of Mag24a
  93. GRB 240421B: GRBAlpha detection
  94. LIGO/Virgo/KAGRA S240422ed: No Counterparts in DDOTI/OAN Optical Observations
  95. GRB 240419A: Possible ATCA radio detection
  96. LIGO/Virgo/KAGRA S240422ed: Magellan Observations
  97. GRB 240414A: radio detection with the VLA
  98. GRB 240421B: AstroSat CZTI detection
  99. GRB240421B: Zadko Observations
  100. Fermi GRB 240421B: Global MASTER-Net observations report

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