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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"

21516 results found.

  1. Swift GRB 230815A: Global MASTER-Net observations report
  2. Fermi GRB 230814A: Global MASTER-Net observations report
  3. GRB 230812B: Iota Scorpii Observatory, La Spezia, Italy
  4. GRB 230812B: Tautenburg observations
  5. GRB 230812B: AMI-LA radio detection of afterglow candidate
  6. GRB 230812B: continued AbAO optical afterglow observations
  7. GRB 230812B: Optical observaions from Rozhen Observatory
  8. GRB 230812B: Further Bassano Bresciano Observatory optical observations
  9. GRB 230812B: further SAO RAS optical observations
  10. GRB 230812B: GRANDMA further observations of ZTF23aaxeacr candidate afterglow
  11. GRB 230812B: CrAO ZTSh optical observations
  12. GRB 230812B: Koshka Zeiss-1000 optical observations
  13. GRB 230812B: Leavitt Observatory optical observations
  14. GRB 230812B : optical observations from Observatoire de Haute-Provence
  15. GRB 230812B: Bassano Bresciano Observatory optical observations
  16. GRB 230812B: Osservatorio Astronomico "Nastro Verde" optical observation
  17. GRB 230812B: OASDG optical observations
  18. GRB 230812B: AbAO optical observations
  19. GRB 230812B: Montarrenti Observatory optical observations
  20. GRB 230812B: SAO RAS optical observations
  21. GRB 230812B: GMG - GRANDMA observations
  22. Konus-Wind detection of GRB 230812B
  23. GRB 230812B: Swift-XRT afterglow detection
  24. GRB 230812: Swift/UVOT Detection
  25. GOTO confirmation and possible host galaxy of GRB230812B optical afterglow
  26. Fermi GRB 230812B: MASTER optical counterpart
  27. GRB 230812B: KAIT Optical Afterglow Candidate
  28. LAT GRB230812.79: Global MASTER-Net observations report
  29. Fermi GRB 230812B: Global MASTER-Net observations report
  30. GRB 230812B: Tiled Swift observations
  31. ZTF23aaoohpy/AT2023lcr: JWST spectroscopy confirmation of an associated type Ic-BL supernova
  32. Fermi trigger No 713525317: Global MASTER-Net observations report
  33. GRB 230805B: Iota Scorpii Observatory, La Spezia, Italy upper limit
  34. GRB 230808A: Swift/BAT-GUANO detection of a burst
  35. Fermi trigger No 713136868: Global MASTER-Net observations report
  36. Fermi trigger No 713205976: Global MASTER-Net observations report
  37. ZTF23aaoohpy/AT2023lcr: JWST observations consistent with the presence of a supernova
  38. transient SPT-SVJ025406.5-702837: ATCA follow-up observations
  39. Fermi GRB 230807A: Global MASTER-Net observations report
  40. Fermi trigger No 713134237: Global MASTER-Net observations report
  41. LIGO/Virgo/KAGRA S230805x: Upper limits from Swift/BAT-GUANO
  42. Konus-Wind detection of GRB 230803A
  43. GRB 230805B : OHP/T193 optical upper limit
  44. GRB 230805B: Swift/UVOT Upper Limits
  45. Fermi trigger No 712991593: Global MASTER-Net observations report
  46. GRB 230805B: Bassano Bresciano observatory upper limit
  47. Fermi trigger No 712987357: Global MASTER-Net observations report
  48. GRB 230805B: NOT optical afterglow confirmation
  49. Fermi GRB 230805A: Global MASTER-Net observations report
  50. GRB 230805B: SAO RAS optical observations
  51. Fermi trigger No 712927418: Global MASTER-Net observations report
  52. Swift GRB 230805B: Global MASTER-Net observations report
  53. Fermi trigger No 712798043: Global MASTER-Net observations report
  54. GRB 230802A: Swift/UVOT Upper Limits
  55. Fermi trigger No 712718833: Global MASTER-Net observations report
  56. Fermi trigger No 712713532: Global MASTER-Net observations report
  57. Fermi trigger No 712651827: Global MASTER-Net observations report
  58. Swift GRB 230802A: Global MASTER-Net observations report
  59. LIGO/Virgo/KAGRA S230802aq: Upper limits from Fermi-GBM Observations
  60. LIGO/Virgo S230802aq: No counterpart candidates in INTEGRAL SPI-ACS prompt observation
  61. LIGO/Virgo/KAGRA S230802aq: Coverage and upper limits from MAXI/GSC observations
  62. IceCube-230724A: JCMT/SCUBA-2 submm observations
  63. IceCube-230707A: JCMT/SCUBA-2 submm observations
  64. LIGO/Virgo/KAGRA S230731an: Upper limits from Swift/BAT-GUANO
  65. LIGO/Virgo/KAGRA S230731an: Coverage and upper limits from MAXI/GSC observations
  66. GRB 230723A: Detection of candidate millimeter-band radiation by SPT-3G
  67. Fermi trigger No 712390645: Global MASTER-Net observations report
  68. Fermi-LAT gamma-ray observations of IceCube-230727A
  69. Fermi trigger No 712306969: Global MASTER-Net observations report
  70. IceCube-230727A: No candidates from the Zwicky Transient Facility
  71. GRB 230728A: Swift/UVOT Upper Limits
  72. GRB 230728A: NOT optical observations and possible host galaxy
  73. IceCube-230724A: No counterparts from the Zwicky Transient Facility
  74. Swift GRB230728.12: Global MASTER-Net observations report
  75. GRB 230727A: Swift/BAT-GUANO detection of a burst
  76. Fermi-LAT gamma-ray observations of IceCube-230725A
  77. Fermi-LAT gamma-ray observations of IceCube-230724A
  78. Fermi trigger No 712143685: Global MASTER-Net observations report
  79. Integral GRB230726.26: Global MASTER-Net observations report
  80. GRB 230723B: Further CAHA observations and host galaxy detection
  81. GRB 230723B: ATCA rapid radio follow-up
  82. Integral GRB230725.99: Global MASTER-Net observations report
  83. IceCube Alert 230725.90: Global MASTER-Net observations report
  84. GRB 230723B: GAD Observatory, La Spezia, Italy upper limit
  85. GRB 230723B: Leavitt Observatory upper limit
  86. GRB 230723B: Osservatorio Astronomico Nastro Verde upper limit
  87. GRB 230723B: Montarrenti Observatory upper limit
  88. GRB 230723B: Optical afterglow candidate from CAHA
  89. GRB 230723B: Bassano Bresciano Observatory upper limit
  90. GRB 230723B: non-detections from Observatoire de Haute-Provence
  91. IceCube Alert 230724.08: Global MASTER-Net observations report
  92. Fermi trigger No 711853834: Global MASTER-Net observations report
  93. Fermi trigger No 711805358: Global MASTER-Net observations report
  94. GRB 230723B: Swift/UVOT Upper Limits
  95. Swift GRB 230723B: Global MASTER-Net observations report
  96. GRB 230723B: Swift-XRT observations
  97. Fermi GRB 230723A: Global MASTER-Net observations report
  98. Swift GRB230720.30: Global MASTER-Net observations report
  99. Fermi trigger No 711088412: Global MASTER-Net observations report
  100. Fermi GRB 230713A: Global MASTER-Net observations report

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