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GCN Circulars

GCN Circulars are rapid bulletins submitted by and distributed to the community. 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"
  1. LIGO/Virgo S230615an: Global MASTER-Net observations report
  2. LIGO/Virgo S230615ak: Global MASTER-Net observations report
  3. GRB 230618A: KAIT Optical Observations
  4. LIGO/Virgo S230617ba: Global MASTER-Net observations report
  5. LIGO/Virgo S230618k: Global MASTER-Net observations report
  6. LIGO/Virgo S230618d: Global MASTER-Net observations report
  7. LIGO/Virgo S230617bc: Global MASTER-Net observations report
  8. LIGO/Virgo S230617aq: Global MASTER-Net observations report
  9. LIGO/Virgo S230617ab: Global MASTER-Net observations report
  10. Swift GRB 230618A: Global MASTER-Net observations report
  11. LIGO/Virgo S230617aj: Global MASTER-Net observations report
  12. GRB230618A: LCOGT Optical Observations
  13. GRB 230618B: Fermi GBM Final Real-time Localization
  14. GRB 230618A: Prompt enhanced Swift-XRT position
  15. GRB 230618A: Swift detection of a burst
  16. GRB 230616A: Swift ToO observations
  17. GRB 230617A: Fermi GBM Final Real-time Localization
  18. LIGO/Virgo/KAGRA S230615az: T80S Search and Candidate Counterpart Identification
  19. LIGO/Virgo/KAGRA S230615az: Non-Detections of GROWTH-India Candidates from GECKO Optical Observations
  20. GRB 230614C: GRBAlpha detection
  21. GRB 230616A: AstroSat CZTI detection
  22. GRB 230616A: Swift/BAT-GUANO detection of a short burst outside the coded FOV
  23. LIGO/Virgo/KAGRA S230615az: Xinglong-2.16m photometric observations of GIT candidates
  24. LIGO/Virgo/KAGRA S230529ay: Upper limits from a two-week IceCube neutrino search
  25. LIGO/Virgo/KAGRA S230615az: GOTO candidate counterparts
  26. LIGO/Virgo S230616s: Global MASTER-Net observations report
  27. LIGO/Virgo S230615be: Global MASTER-Net observations report
  28. LIGO/Virgo S230615af: Global MASTER-Net observations report
  29. LIGO/Virgo S230616j: Global MASTER-Net observations report
  30. LIGO/Virgo/KAGRA S230615az: GROWTH-India candidates
  31. LIGO/Virgo S230615av: Global MASTER-Net observations report
  32. LIGO/Virgo S230615az: Global MASTER-Net observations report
  33. LIGO/Virgo S230615ax: Global MASTER-Net observations report
  34. LIGO/Virgo S230615k: Global MASTER-Net observations report
  35. GRB 230614C: AstroSat CZTI detection
  36. LIGO/Virgo S230615t: Global MASTER-Net observations report
  37. GRB 230614B: Fermi GBM Observation
  38. GRB 230614C: Fermi GBM Detection
  39. LIGO/Virgo S230615i: Global MASTER-Net observations report
  40. LIGO/Virgo S230613at: Global MASTER-Net observations report
  41. LIGO/Virgo S230614ac: Global MASTER-Net observations report
  42. LIGO/Virgo S230614t: Global MASTER-Net observations report
  43. LIGO/Virgo S230614o: Global MASTER-Net observations report
  44. GRB 230614B: Swift/BAT-GUANO detection outside the coded FOV
  45. Fermi trigger No 708426906: Global MASTER-Net observations report
  46. GRB 230614B: Fermi GBM Final Real-time Localization
  47. GRB 230614A: Fermi GBM Final Real-time Localization
  48. GRB 230606A: LCOGT Optical Observations
  49. IceCube-Cascade 230610A: Upper limits from a search for additional neutrino events in IceCube
  50. LIGO/Virgo/KAGRA S230608as: Updated Sky localization
  51. LIGO/Virgo/KAGRA S230606d: Updated Sky localization
  52. LIGO/Virgo S230611be: Global MASTER-Net observations report
  53. LIGO/Virgo S230611l: Global MASTER-Net observations report
  54. LIGO/Virgo/KAGRA S230609u: Updated Sky localization
  55. LIGO/Virgo S230609u: Global MASTER-Net observations report
  56. GRB 230608A: CALET Gamma-Ray Burst Monitor detection
  57. GRB 230608A: AstroSat CZTI detection
  58. GRB 230608A: AGILE detection
  59. LIGO/Virgo S230608aw: Global MASTER-Net observations report
  60. LIGO/Virgo/KAGRA S230609u: Identification of a GW compact binary merger candidate
  61. LIGO/Virgo S230608as: Global MASTER-Net observations report
  62. LIGO/Virgo S230609a: Global MASTER-Net observations report
  63. LIGO/Virgo S230608ah: Global MASTER-Net observations report
  64. LIGO/Virgo S230608q: Global MASTER-Net observations report
  65. ZTF23aamxeqf/AT2023jxk: 1.3m DFOT Optical upper limit
  66. LIGO/Virgo/KAGRA S230608as: Identification of a GW compact binary merger candidate
  67. Fermi GRB 230603A: Global MASTER-Net observations report
  68. Fermi trigger No 707039690: Global MASTER-Net observations report
  69. GRB 230506B: Chandra localization of the X-ray afterglow
  70. ZTF and GIT Observations of the Candidate Optical Afterglow AT2023jxk
  71. GRB 230606A: Swift-BAT refined analysis
  72. GRB 230606A: Gaoyazi/GOT optical upper limit
  73. GRB 230606A: Fermi GBM Observation
  74. GRB 230606A: BOOTES-5/JGT optical upper limit
  75. LIGO/Virgo/KAGRA S230602ap: Zwicky Transient Facility observations
  76. GRB 230606A: Swift-XRT refined Analysis
  77. GRB 230604A: GRBAlpha detection
  78. GRB 230606A: Swift/UVOT Upper Limits
  79. LIGO/Virgo S230606z: Global MASTER-Net observations report
  80. GRB 230606A: Enhanced Swift-XRT position
  81. LIGO/Virgo S230606d: Global MASTER-Net observations report
  82. LIGO/Virgo/KAGRA S230606d: Identification of a GW compact binary merger candidate
  83. GRB 230606A: Swift detection of a burst
  84. Fermi-LAT gamma-ray observations of IceCube-230603A
  85. LIGO/Virgo/KAGRA S230605o: Updated Sky localization
  86. IceCube-230603A: Upper limits from a search for additional neutrino events in IceCube
  87. LIGO/Virgo/KAGRA S230601bf: Updated Sky localization
  88. Super-Kamiokande: Neutrino search for SN2023ixf
  89. GRB 230604A: AstroSat CZTI detection of a short GRB
  90. LIGO/Virgo/KAGRA S230605o: Identification of a GW compact binary merger candidate
  91. LIGO/Virgo S230605o: Global MASTER-Net observations report
  92. LIGO/Virgo S230604z: Global MASTER-Net observations report
  93. IceCube-230603A - IceCube observation of a high-energy neutrino candidate track-like event
  94. GRB 230603A: Fermi GBM Final Real-time Localization
  95. LIGO/Virgo S230603aa: Global MASTER-Net observations report
  96. LIGO/Virgo S230602ap: Global MASTER-Net observations report
  97. LIGO/Virgo/KAGRA S230518h: Upper limits from a two-week IceCube neutrino search
  98. GRB 230521A: VZLUSAT-2 detection
  99. GRB 230522A: GRBAlpha and VZLUSAT-2 joint detection
  100. LIGO/Virgo S230601bf: Global MASTER-Net observations report

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