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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"

11762 results found.

  1. GRB 230812B: Assy optical observations, possible SN rise
  2. GRB 230812B: SAO RAS RC-500 and Zeiss-1000 observations
  3. Konus-Wind detection of GRB 230818A
  4. GRB 230820A: AstroSat CZTI detection
  5. LIGO/Virgo/KAGRA S230820bq: Identification of a GW compact binary merger candidate
  6. Swift GRB230820.82: Global MASTER-Net observations report
  7. Swift Triggers 1186280 and 1186291 are not GRBs
  8. GRB 230818A: SAO RAS 6-m telescope spectroscopy
  9. GRB 230818A: AstroSat CZTI detection
  10. Fermi GRB 230818A: Global MASTER-Net observations report
  11. Fermi trigger No 713974668: Global MASTER-Net observations report
  12. Swift GRB230818.98: Global MASTER-Net observations report
  13. GRB 230812B: SAO RAS observations, possible re-brightening
  14. GRB 230817A: AstroSat CZTI detection
  15. GRB 230815A: VLT/HAWK-I near-infrared afterglow detection
  16. GRB 230812B: SAO RAS optical observations
  17. GRB 230816A: Tautenburg observations
  18. GRB 230816A: AKO Optical Observations
  19. GRB 230816A: TShAO and Assy optical observations
  20. Swift GRB230816.80: Global MASTER-Net observations report
  21. GRB 230816A: Nanshan/HMT optical afterglow detection
  22. GRB 230815B: GECAM-B and GECAM-C detection of a burst
  23. GRB 230815B: AstroSat CZTI detection
  24. GRB 230812B: continued SAO RAS optical observation
  25. GRB 230812B: Iota Scorpii Observatory, La Spezia, Italy
  26. GRB 230812B: further SAO RAS optical observations
  27. GRB 230812B: GIT optical follow-up
  28. GRB 230812B: Leavitt Observatory optical observations
  29. GRB 230812B : optical observations from Observatoire de Haute-Provence
  30. GRB 230812B: Montarrenti Observatory optical observations
  31. GRB 230812B: SAO RAS optical observations
  32. Konus-Wind detection of GRB 230812B
  33. GRB 230812B: GECAM-C observation of a very bright burst
  34. GRB 230812B: Swift-XRT afterglow detection
  35. GRB 230812B: Improved Swift/XRT localization
  36. GRB 230812B: Fermi-LAT detection
  37. Fermi GRB 230812B: Global MASTER-Net observations report
  38. GRB 230812B: Fermi GBM detection of an extremely bright GRB
  39. GRB 230805B: Iota Scorpii Observatory, La Spezia, Italy upper limit
  40. GRB 230805B: AstroSat CZTI detection
  41. Fermi trigger No 713136868: Global MASTER-Net observations report
  42. The Fermi GBM Trigger 713134237 / 230807868 is not associated with LIGO/Virgo/KAGRA S230807f.
  43. LIGO/Virgo/KAGRA S230807f: Identification of a GW compact binary merger candidate
  44. LIGO/Virgo/KAGRA S230805x: Upper limits from Swift/BAT-GUANO
  45. Konus-Wind detection of GRB 230803A
  46. GRB 230805B : OHP/T193 optical upper limit
  47. LIGO/Virgo/KAGRA S230806ak: Identification of a GW compact binary merger candidate
  48. GRB 230805B: Bassano Bresciano observatory upper limit
  49. GRB 230805B: BOOTES-6/DPRT optical upper limit and 1.5m OSN detection
  50. GRB 230805B: Swift-XRT refined Analysis
  51. GRB 230805B: Swift detection of a burst
  52. GRB 230802B: AstroSat CZTI detection
  53. IPN triangulation of GRB 230803A
  54. GRB 230803A: AstroSat CZTI detection
  55. LIGO/Virgo/KAGRA S230802aq: AstroSat CZTI non-detection and upper limits
  56. Fermi trigger No 712713532: Global MASTER-Net observations report
  57. LIGO/Virgo/KAGRA S230802aq: Coverage and upper limits from MAXI/GSC observations
  58. LIGO/Virgo/KAGRA S230731an: Upper limits from Swift/BAT-GUANO
  59. LIGO/Virgo/KAGRA S230731an: AstroSat CZTI non-detection and upper limits
  60. LIGO/Virgo/KAGRA S230731an: Coverage and upper limits from MAXI/GSC observations
  61. Fermi-LAT gamma-ray observations of IceCube-230727A
  62. GRB 230728A: Fermi GBM Observation
  63. GRB 230728A: Swift-XRT refined Analysis
  64. GRB 230727A: AstroSat CZTI detection
  65. GRB 230728A: Swift detection of a burst
  66. Fermi-LAT gamma-ray observations of IceCube-230725A
  67. Fermi-LAT gamma-ray observations of IceCube-230724A
  68. Konus-Wind detection of GRB 230723A
  69. GRB 230723B: MITSuME Akeno optical afterglow candidate detection
  70. Integral GRB230725.99: Global MASTER-Net observations report
  71. IceCube Alert 230725.90: Global MASTER-Net observations report
  72. GRB 230723B: Osservatorio Astronomico Nastro Verde upper limit
  73. GRB 230723B: Optical afterglow candidate from CAHA
  74. GRB 230723B: Swift-XRT refined Analysis
  75. GRB 230723B: non-detections from Observatoire de Haute-Provence
  76. IceCube Alert 230724.08: Global MASTER-Net observations report
  77. Fermi trigger No 711853834: Global MASTER-Net observations report
  78. GRB 230723B: Optical limit from CAHA
  79. Swift-XRT position for GRB 230723B
  80. Swift GRB230720.30: Global MASTER-Net observations report
  81. IceCube-230707A : MAXI upper limit and NICER follow-up observation of Swift J1753.5-0127
  82. GRB 230709C: Swift/BAT-GUANO detection of a short burst outside the coded FOV
  83. IceCube-230708A: Upper limits from Swift/BAT-GUANO
  84. GRB 230712B: Fermi GBM Final Localization
  85. GRB 230709C: AstroSat CZTI detection
  86. Fermi-LAT gamma-ray observations of IceCube-230708A
  87. Fermi-LAT gamma-ray observations of IceCube-230707B
  88. Fermi-LAT gamma-ray observations of IceCube-230707A
  89. GRB 230707B: Swift/BAT-GUANO detection of a burst outside the coded FOV
  90. IceCube Alert 230708.35: Global MASTER-Net observations report
  91. GRB 230707B: Fermi GBM Final Real-time Localization
  92. Integral GRB230706.70: Global MASTER-Net observations report
  93. Fermi trigger No 710117592: Global MASTER-Net observations report
  94. GRB 230328B: LBT detection of the likely host galaxy
  95. Konus-Wind detection of GRB 220623A
  96. LIGO/Virgo/KAGRA S230627c: Upper limits from Swift/BAT-GUANO
  97. GRB 230625B: AstroSat CZTI detection
  98. GRB 230628E: Swift-XRT refined Analysis
  99. GRB 230628D: BALROG localization (Fermi Trigger 709676556 / GRB 230628849)
  100. GRB 230628D: Fermi GBM Final Real-time Localization

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