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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"

19043 results found.

  1. GRB 160408A: GMG observation limit
  2. GRB 160408A: TLS Tautenburg observations
  3. GRB 160408A: Swift/UVOT Upper Limits
  4. GRB 160408A: Gemini optical observations
  5. GRB 160408A: Enhanced Swift-XRT position
  6. GRB 160408A: Swift detection of a short burst
  7. IPN Triangulation of GRB 160406A (short/hard)
  8. GRB 160401A: Swift-XRT observations
  9. GRB 160401A: Swift/UVOT Upper Limits
  10. GRB 160401A: Zadko observatory - Gingin optical observations
  11. GRB 160401A: Swift ToO observations
  12. GRB 160327A: Continued RATIR Optical and NIR Observations
  13. LIGO/Virgo G211117: LOFAR follow-up
  14. GRB 160327A: Imaging and spectroscopy from GTC
  15. GRB 160327A: Continued RATIR Optical and NIR Observations
  16. GRB 160327A: Mondy optical upper limit
  17. GRB 160327A: Swift/UVOT Upper Limits
  18. GRB 160327A: Enhanced Swift-XRT position
  19. GRB 160327A: RATIR Optical and NIR Afterglow Detection
  20. GRB 160327A: Swift detection of a burst
  21. GRB 160325A: GROND Upper Limits
  22. GRB 160325A: afterglow confirmation
  23. GRB 160325A: Enhanced Swift-XRT position
  24. Swift Trigger 680457 is not a GRB
  25. LIGO/Virgo G211117: CALET GBM Observations
  26. GRB160325A: REM NIR observations
  27. GRB 160325A: Swift detection of a burst
  28. Swift detects GX 301-2 in very high state
  29. GRB 160321A: AbAO optical observations
  30. GRB 160321A: Possible RATIR Optical and NIR Detections
  31. GRB 160321A: Swift/UVOT Upper Limits
  32. GRB 160321A: Swift-XRT refined Analysis
  33. GRB 160316A: CALET Gamma-Ray Burst Monitor detection
  34. GRB 160321A: Enhanced Swift-XRT position
  35. GRB 160321A: Swift detection of a probable burst
  36. GRB 160310A: Terskol 2-m observations
  37. IPN Triangulation of GRB 160310A
  38. LIGO/Virgo G211117: EWE for NOWT follow-up of northern sky
  39. GRB 160310A: A further Swift-XRT observation, no afterglow detected
  40. Swift detection of a likely new SGR: SGR 0755-2933
  41. GRB 160314A: Continued RATIR Optical and NIR Observations
  42. GRB 160313A: Mondy optical upper limit
  43. GRB 160314A: GROND optical/NIR observations
  44. GRB 160314A: ISON-Ussuriysk optical upper limit, updated photometry and correction of GCN 19184
  45. GRB 160314B: Fermi GBM observation
  46. GRB 160314A: RATIR Optical and NIR Observations
  47. GRB 160314A: Mondy optical observations
  48. GRB 160313A: Swift/UVOT Upper Limits
  49. LIGO/Virgo G194575: EWE for NOWT follow-up of northern sky
  50. GRB 160314A: Optical observations from OSN
  51. GRB 160314A: Swift/UVOT Detection
  52. GRB 160228A: GROND afterglow confirmation and X-shooter host candidate redshift
  53. GRB 160314A: Enhanced Swift-XRT position
  54. GRB 160314A: ISON-Ussuriysk optical upper limit
  55. GRB 160314A: Weihai optical upper limit
  56. GRB 160314A: Swift detection of a burst
  57. GRB 160313A: Chante-Perdrix Observatory optical observations
  58. GRB 160313A: Swift-XRT refined Analysis
  59. GRB 160313A: TAROT Calern observatory optical observations
  60. GRB 160313A: Enhanced Swift-XRT position
  61. GRB 160313A: RATIR Optical and NIR Observations
  62. GRB 160313A: SAO RAS observations
  63. GRB 160313A: Swift detection of a burst
  64. GRB 160310A: Further NOT observations
  65. GRB 160310A: Swift/UVOT Upper Limits
  66. GRB 160310A: RATIR Optical and NIR Observations
  67. GRB 160310A: NOT optical observations
  68. GRB 160310A: LCOGT-SAAO optical upper limits
  69. GRB 160303A: GTC imaging of possible host galaxy
  70. GRB 160310A: Swift ToO observations
  71. GRB 160310A: Fermi-LAT detection
  72. LIGO/Virgo G211117: HAWC follow-up of northern sky
  73. Swift trigger 677890 is noise
  74. GRB 160303A: Continued optical monitoring from NOT
  75. GRB160303A: further GROND observations
  76. GRB 160303A: 9.8 GHz VLA upper limit
  77. GRB 160303A, Swift-BAT refined analysis
  78. GRB 160303A: Continued RATIR Optical and NIR Observations
  79. GRB 160303A: GROND Optical Detection
  80. GRB 160303A: Observations from T150 OSN
  81. GRB 160303A: VLT/FORS2 afterglow obervations
  82. GRB 160303A: BOAO R-band Detection
  83. GRB 160303A: McDonald 2.1m CQUEAN Detection
  84. GRB 160303A iTelescope observation
  85. GRB 160303A: Optical observations from the NOT
  86. Swift possibly triggered on IGR17091-3624
  87. GRB 160303A: Swift/UVOT Detection
  88. GRB 160303A: RAPTOR Observations During Gamma-Ray Emitting Interval
  89. GRB 160303A: Enhanced Swift-XRT position
  90. GRB 160303A: RATIR Optical and NIR Afterglow Detection
  91. GRB 160303A: MITSuME Okayama upper limits
  92. GRB 160303A: ISON-NM early optical early limits
  93. GRB 160303A: Swift detection of a burst, possibly short
  94. GRB 160227A: LOAO 1.0m optical detection
  95. GRB 160227A: McDonald 0.8m Detection
  96. GRB 160228A: Swift/UVOT Upper Limits
  97. GRB 160227A: Swift/UVOT Detection
  98. GRB 160228A: Mondy optcial observations
  99. GRB 160228A: RATIR Optical and NIR Observations
  100. GRB 160228A: Swift-XRT refined Analysis

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