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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"

45442 results found.

  1. GRB 240805B Bassano Bresciano Observatory upper limit
  2. GRB240805A: Fermi GBM Observation
  3. GRB 240805B: JinShan optical afterglow detection
  4. GRB 240804B/EP240804a: Correction to the GRB name in GCN 37071
  5. GRB 240805B: AbAO, CrAO, and Terskol optical upper limits
  6. Konus-Wind detection of GRB 240804B (a counterpart of EP240804a)
  7. Fermi Gamma-ray Burst Monitor trigger 240806402/744629911 is not a GRB
  8. EP240806a: EP-FXT detection of the X-ray emission
  9. GRB 240626B: VZLUSAT-2 detection
  10. GRB 240624B: VZLUSAT-2 detection
  11. GRB 240619C: VZLUSAT-2 detection
  12. EP 240806A: LCO optical observations
  13. EP240806a: GSP optical counterpart detection
  14. EP240806a: EP-WXT detection of a fast X-ray transient
  15. GRB 240805B: Optical detection with 1.6m Mephisto
  16. EP240804a: BOOTES-6/DPRT optical detection
  17. GRB 240805B: NUTTelA-TAO / BSTI Optical Limits
  18. GRB 240805B: Swift-XRT refined Analysis
  19. Fermi trigger No 744544656: Global MASTER-Net observations report
  20. GRB 240805B: Swift/UVOT Upper Limits
  21. GRB 240805A: Swift/UVOT Upper Limits
  22. GRB 240805B: BTA optical afterglow candidate
  23. GRB 240805A: SVOM/GRM observation
  24. GRB 240805B: Enhanced Swift-XRT position
  25. GRB 240805B: LCOGT Optical Upper Limits
  26. Swift GRB 240805B: Global MASTER-Net observations report
  27. GRB 240805B: JinShan optical upper limits
  28. EP240801a: BTA BVRI photometry
  29. Fermi GRB 240805A: Global MASTER-Net observations report
  30. Swift GRB 240805A: Global MASTER-Net observations report
  31. Fermi Gamma-ray Burst Monitor trigger 744558410/240805574 is not a GRB
  32. GRB 240805A: Swift-XRT refined Analysis
  33. EP240804a: GSP detects optical candidate counterpart
  34. GRB 240805B: Swift detection of a burst
  35. GRB 240805A: Fermi-LAT detection
  36. GRB 240805A: INTEGRAL spectral analysis
  37. EP240801a: Continued optical observations at ZTSh (CraO)
  38. EP240804a: VLT/X-shooter spectroscopic redshift
  39. EP240804a: LCOGT optical counterpart detection
  40. GRB 240805A: A long GRB detected by INTEGRAL
  41. EP-WXT trigger 00109017646 is not a real source
  42. EP240804a: NOT optical counterpart detection
  43. EP240804a: EP-WXT detection and EP-FXT follow-up observation of a fast X-ray transient
  44. EP240802a: correction of EP-WXT trigger time in GCN 37019
  45. GRB 240805A: Swift detection of a burst
  46. GRB 240805A: Fermi GBM Final Real-time Localization
  47. Fermi GRB 240804A: Global MASTER-Net observations report
  48. EP240802a: Montarrenti Observatory optical upper limit
  49. GRB 240804A: Fermi GBM Final Real-time Localization
  50. Fermi trigger No 744459130: Global MASTER-Net observations report
  51. IPN triangulation of GRB 240802A / EP 240802a
  52. Fermi Gamma-ray Burst Monitor trigger 744459130/240804425 is not a GRB
  53. EP240801a: Osservatorio Astronomico Nastro Verde upper limit
  54. EP240802A: Bassano Bresciano Observatory upper limit
  55. GRB 240802A: SVOM/GRM observation
  56. EP240802a: Time coincidence with GRB 240802A and optical upper limits with Kinder observations
  57. Fermi trigger No 744278264: Global MASTER-Net observations report
  58. EP240802a: EP-WXT detection and EP-FXT follow-up observation of a fast X-ray transient
  59. GRB 240802A: AstroSat CZTI detection of a long burst
  60. EP240801a: further SAO RAS optical observations
  61. EP240801a: optical observations at CrAO and AbAO
  62. EP240801a: GRANDMA and Kilonova-Catcher optical observations
  63. EP240801a: Leavitt Observatory optical observations
  64. EP240801a: GTC spectroscopy and absorption redshift
  65. EP240801a: SAO RAS optical observations
  66. GRB 240801B: AstroSat CZTI Updated classification - likely a solar flare
  67. EP240801a: JinShan optical observations
  68. GRB 240727C: SVOM/GRM observation
  69. EP240801a: NOT optical observations
  70. EP240801a: follow-up observation with LCOGT
  71. Fermi GBM trigger 744179961 / 240801194 can not be confirmed as a GRB
  72. GRB 240730A: Swift-BAT refined analysis
  73. EP240801a: GSP follow-up observations of the candidate counterpart
  74. Fermi trigger No 744204856: Global MASTER-Net observations report
  75. EP240801a: Kinder follow-up observations of the candidate counterpart
  76. EP240708a: Kinder follow-up observations of the candidate counterpart (duplicate submission of GCN 37002)
  77. EP240801a: KAIT optical counterpart observations
  78. EP240801a: GMG observation
  79. EP240801a: TRT optical counterpart detection
  80. EP240801a: EP-WXT detection and EP-FXT follow-up observation of a fast X-ray transient
  81. GRB 240801B: AstroSat CZTI detection of a bright long burst
  82. Fermi GRB 240801A: Global MASTER-Net observations report
  83. GRB 240801A: Fermi GBM Final Real-time Localization
  84. GRB 240730C: AstroSat CZTI detection of a long burst
  85. GRB 240731A: Fermi GBM Final Localization
  86. Fermi trigger No 744128417: Global MASTER-Net observations report
  87. Fermi trigger No 744083370: Global MASTER-Net observations report
  88. GRB 240731A: AstroSat CZTI detection
  89. GRB 240730A: Osservatorio Astronomico Nastro Verde upper limit
  90. GRB240730A: BOOTES-5/JGT early optical upper limit
  91. Fermi Gamma-ray Burst Monitor trigger 744061103/240730818 is not a GRB
  92. Fermi GRB 240730B: Global MASTER-Net observations report
  93. GRB 240730B: Fermi GBM Final Real-time Localization
  94. Swift GRB 240730A: Global MASTER-Net observations report
  95. GRB 240730A: Swift-XRT refined Analysis
  96. GRB 240715A: Swift-XRT afterglow detection
  97. GRB 240730A: KAIT Optical Upper Limit
  98. GRB 240727C: GRBAlpha detection
  99. GRB 240730A: Swift/UVOT Upper Limits
  100. GRB 240730A: Enhanced Swift-XRT position

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