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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').
  1. GRB 240607A: Fermi GBM detection of a very bright burst
  2. GRB 240529A: radio detection with AMI-LA
  3. GRB 240607A: BALROG localization (Fermi Trigger 739450879 / GRB 240607459)
  4. GRB 240607A: Fermi GBM Final Real-time Localization
  5. GRB 240606B: GECAM-B detection a long burst
  6. Fermi trigger No 739373591: Global MASTER-Net observations report
  7. GRB 240606B: Swift-XRT afterglow detection
  8. Swift GRB240606.15: Global MASTER-Net observations report
  9. GRB 240606B: Swift ToO observations
  10. GRB 240606B: Swift/BAT-GUANO arcminute localization of a burst
  11. Konus-Wind detection of GRB 240603A
  12. Swift Trigger 1235109: a possible GRB 240606A
  13. Fermi GRB 240604A: Global MASTER-Net observations report
  14. IPN triangulation of GRB 240531A (short)
  15. Fermi GRB 240605A: Global MASTER-Net observations report
  16. Fermi GRB 240605C: Global MASTER-Net observations report
  17. Fermi Gamma-ray Burst Monitor trigger 739290883/240605607 is not a GRB
  18. LIGO/Virgo/KAGRA S240601co: Updated Sky localization
  19. GRB 240605C: Fermi GBM Final Real-time Localization
  20. IPN triangulation of GRB 240603A
  21. GRB 240605B: Fermi GBM Final Real-time Localization
  22. GRB 240604A: Fermi GBM Final Localization
  23. GRB 240605A: Fermi GBM Final Real-time Localization
  24. GRB 240604A: GECAM detection of a long burst
  25. GRB 240529A: SAO RAS optical observations
  26. Swift Trigger 1232755: likely consistent with noise and not astrophysical
  27. Fermi GRB 240603C: Global MASTER-Net observations report
  28. LIGO/Virgo/KAGRA S240601co: Upper limits from Swift/BAT-GUANO
  29. LIGO/Virgo/KAGRA S240530a: Upper limits from Swift/BAT-GUANO
  30. GRB 240603A: Fermi GBM Final Localization
  31. GRB 240603C: BALROG localization (Fermi Trigger 739102156 / GRB 240603423)
  32. GRB 240603C: Fermi GBM Final Real-time Localization
  33. Swift Trigger 1232465: consistent with noise
  34. GRB 240603B: Swift detection of a possible burst
  35. GRB 240529A: MASTER prompt OT detection
  36. GRB 240603A: GECAM detection of a short burst
  37. GRB 240529A: continued SAO RAS optical observations
  38. Fermi GRB 240602A: Global MASTER-Net observations report
  39. GRB 240529A: OSN optical detection
  40. The EP-WXT source triggered on June 1st is likely a flaring star
  41. GRB 240529A: further SAO RAS optical observations
  42. LIGO/Virgo/KAGRA S240601aj: Updated Sky localization
  43. GRB 240602A: Fermi GBM Final Real-time Localization
  44. LIGO/Virgo/KAGRA S240601co: Identification of a GW compact binary merger candidate
  45. Swift Trigger 1232465 is not a GRB
  46. GRB 240529A: AKO Optical Afterglow Follow-Up Observations
  47. LIGO/Virgo/KAGRA S240530a: Updated Sky localization
  48. LXT 240528A: GSP optical upper limit
  49. GRB 240529A: 1.3m DFOT Optical observations
  50. LIGO/Virgo/KAGRA S240527en: Updated Sky localization
  51. LIGO/Virgo/KAGRA S240601aj: Identification of a GW compact binary merger candidate
  52. GRB 240531A: AstroSat CZTI detection of a short burst
  53. GRB 240529A : Mondy optical observations
  54. Konus-Wind detection of GRB 240529A
  55. IPN triangulation of the initial episode of GRB 240529A
  56. GRB 240529A: SAO RAS optical observations
  57. LIGO/Virgo/KAGRA S240531bp: Updated Sky localization
  58. LIGO/Virgo/KAGRA S240531bp: Identification of a GW compact binary merger candidate
  59. GRB 240529A: MAAO 0.7m telescope optical afterglow detection
  60. GRB 240529A: Insight-HXMT/HE detection
  61. GRB 240529A: optical photometry from Konkoly
  62. GRB 240529A: GROWTH-India optical follow-up
  63. GRB 240529A: T193/MISTRAL observations
  64. GRB 240529A: Redshift from GTC/OSIRIS+
  65. GRB 240529A: AKO Optical Afterglow Detection
  66. LIGO/Virgo/KAGRA S240530a: Identification of a GW compact binary merger candidate
  67. LIGO/Virgo/KAGRA S240527fv: Upper limits from Swift/BAT-GUANO
  68. LIGO/Virgo/KAGRA S240525p: Upper limits from Swift/BAT-GUANO
  69. GRB 240529A: J-band detections with WINTER
  70. GRB 240529A: Skynet Optical Observations
  71. LXT 240528A: LEIA detection of a fast X-ray transient
  72. GRB 240529A: Swift-BAT refined analysis
  73. LIGO/Virgo S240527fv: GRANDMA/FRAM-Auger Optical Observations
  74. GRB 240529A: Swift-XRT refined Analysis
  75. GRB240529A: BOOTES-6/DPRT optical detection
  76. GRB 240529A: Swift/UVOT Detection
  77. GRB 240529A: NOT optical observations
  78. GRB 240529A: AstroSat CZTI detection
  79. GRB 240529A: GOTO optical afterglow detection
  80. GRB 240527B: Swift-XRT afterglow detection
  81. GRB 240529A: Enhanced Swift-XRT position
  82. GRB 240529A: Swift detection of a burst with an optical counterpart
  83. Swift GRB240529.12: Global MASTER-Net observations report
  84. LIGO/Virgo/KAGRA S240527fv: Updated Sky localization
  85. GRB 240527B: Fermi GBM Observation
  86. Fermi GRB 240527A: Global MASTER-Net observations report
  87. LIGO/Virgo/KAGRA S240527fv: Identification of a GW compact binary merger candidate
  88. GRB 240527B: Fermi-LAT detection
  89. LAT GRB240527.59: Global MASTER-Net observations report
  90. LIGO/Virgo/KAGRA S240527en: Identification of a GW compact binary merger candidate
  91. Fermi GRB 240527B: Global MASTER-Net observations report
  92. GRB 240527B: Fermi GBM Final Localization
  93. GRB 240527B: BALROG localization (Fermi Trigger 738511436 / GRB 240527586)
  94. GRB 240527A: Fermi GBM Final Real-time Localization
  95. GRB 240523A: Swift-BAT refined analysis
  96. Fermi trigger No 738348224: Global MASTER-Net observations report
  97. Fermi trigger No 738330463: Global MASTER-Net observations report
  98. LIGO/Virgo/KAGRA S240525p: Updated Sky localization
  99. LIGO/Virgo/KAGRA S240525p: Identification of a GW compact binary merger candidate
  100. GRB 240523A: Swift-XRT refined Analysis

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