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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"
  1. GRB 170102A: Astrosat CZTI detection
  2. GRB170104.78 MASTER-Net OT detection
  3. LIGO/Virgo G268556: INTEGRAL search of temporally coincident prompt hard X-ray emission
  4. LIGO/Virgo G268556: Fermi GBM Observations
  5. LIGO/Virgo G268556: Identification of a GW CBC Candidate
  6. GRB 170102A: POLAR observation
  7. Konus-Wind observation of GRB 170101A
  8. GRB 170101B: POLAR observation
  9. GRB 170101B: Lomonosov BDRG gamma ray discovery
  10. GRB 170101A: Lomonosov BDRG gamma ray discovery
  11. Swift trigger 729600 is not an astrophysical event
  12. GRB 161228C: POLAR observation
  13. GRS 1716-249/GRO J1719-24/V2293 Oph, Swift-BAT refined analysis
  14. GRB 170101A: POLAR observation
  15. GRB 161229A: POLAR observation
  16. GRB 170101A: Swift-BAT refined analysis
  17. Trigger 729410: Swift detection of V2293 Oph
  18. GRB 170101B: Astrosat CZTI detection
  19. GRB 170101B: Fermi GBM detection
  20. GRB 170101A: Swift detection of a burst
  21. GRB 161228B: POLAR Observation
  22. GRB 161228A: POLAR Observation
  23. GRB161219B - Anticipated hyperluminal evidence
  24. GRB 161214B: MASTER-Kislovodsk early optical observations
  25. GMRT radio detection of GRB 161219B
  26. GRB 161214A: MASTER-IAC early optical observations
  27. GRB 161219B: Spectroscopic detection of the associated SN with OSIRIS/GTC
  28. Fermi GBM trigger 504490076/161227005 is not a GRB
  29. GRB 161224A: TSHAO optical observations
  30. GRB 161224A: Swift/UVOT Upper limits
  31. GRB 161224A: Swift-XRT refined Analysis
  32. GRB 161224A: Swift-BAT refined analysis
  33. Trigger 728094, Swift-BAT refined analysis
  34. Swift Trigger 728268: a possible GRB
  35. Fermi GBM trigger 504233075/161224301 is not a GRB
  36. Swift Trigger 728094: a possible GRB
  37. GRB 161219B: UKIRT near-IR afterglow detection
  38. GRB 161219B: POLAR Observation
  39. GRB161219.78 MASTER-Net OT detection
  40. Fermi GBM trigger 504061556/161222046 is not a GRB
  41. GRB 161219B: Rapid ALMA Observations & Detection
  42. Correction to GCN 20323 "Konus-Wind observation of GRB 161219B"
  43. Fermi GBM trigger 504043585/161221838 is not a GRB
  44. GRB 161220A: Swift-BAT refined analysis
  45. GRB 161218B: Astrosat CZTI detection
  46. Konus-Wind observation of GRB 161219B
  47. GRB 161219B: SALT observations
  48. GRB 161219B: VLT/X-shooter redshift
  49. Fermi GBM trigger 503982114/161221126 is not a GRB
  50. GRB 161214B: optical spectroscopy of the foreground SDSS object
  51. GRB 161202A: 15 GHz upper limits from AMI
  52. GRB 161129A: 15 GHz upper limits from AMI
  53. GRB 161220A: Swift-XRT refined Analysis
  54. GRB 161220A: LCO-FTS observations
  55. GRB 161219B: MITSuME Akeno Optical Observation
  56. GRB 161219B: VLA Detection
  57. GRB 161220A: GROND Upper Limits
  58. GRB 161217C: POLAR observation
  59. GRB 161217B: POLAR Observation
  60. GRB 161219B: ISON/Terskol optical observations
  61. GRB 161219B: Swift-BAT refined analysis
  62. GRB 161220A: Swift/UVOT Upper Limits
  63. GRB 161219B: Swift/UVOT Detection
  64. GRB 161219B: Watcher optical observations
  65. Konus-Wind observation of GRB 161218B
  66. IPN Triangulation of GRB 161218B (long/very bright)
  67. GRB 161220A: Swift detection of a burst
  68. GRB 161212A: POLAR Detection
  69. GRB 161219B: LCO Sutherland observations
  70. GRB 161219B: GROND afterglow observations
  71. GRB 161219B: Swift-XRT refined Analysis
  72. GRB 161219B: Enhanced Swift-XRT position
  73. GRB 161219B: Swift detection of a burst with an optical afterglow
  74. GRB 161219A: a long GRB detected by INTEGRAL
  75. GRB 161218A: CALET Gamma-Ray Burst Monitor detection
  76. GRB 161218A: Swift-BAT refined analysis
  77. Konus-Wind observation of GRB 161218A
  78. Swift Trigger 727422 is not an astrophysical event.
  79. GRB 161218A: TAROT Calern observatory optical observations
  80. GRB 161217A: TAROT Calern observatory optical observations
  81. GRB 161218B: POLAR observation
  82. GRB 161218A: POLAR observation
  83. GRB 161218B: Fermi GBM detection
  84. GRB 161217A: MITSuME Okayama upper limits
  85. GRB 161217A: Swift-BAT refined analysis
  86. GRB 161218A: Swift detection of a burst
  87. GRB 161217A: Swift/UVOT Upper Limits
  88. GRB 161217A: Swift-XRT refined Analysis
  89. GRB 161214B: AbAO and ISON/Terskol optical observations
  90. GRB 161217A: Enhanced Swift-XRT position
  91. GRB 161207A: POLAR observation
  92. GRB 161217A: Swift detection of a burst
  93. GRB 161214B: Mondy optical observations
  94. GRB 161213A: POLAR Observation
  95. GRB 161207B: POLAR observation
  96. GRB 161205A: POLAR observation
  97. GRB 161210A: POLAR observation
  98. GRB 161214B: Swift-BAT refined analysis
  99. Fermi-LAT Gamma-ray Observations of IceCube-161210
  100. GRB 161214B: Swift/UVOT Afterglow Confirmation

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