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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 180514A: MITSuME Ishigakijima optical upper limits
  2. GRB 180514A: CrAO/ZTSH optical observations and afterglow candidate
  3. GRB 180505A: AstroSat CZTI detection
  4. GRB 180514A: Swift/UVOT Upper Limits
  5. GRB 180514A: MITSuME Akeno optical upper limits
  6. GRB 180514A: Detection limits from 2.5m NOT
  7. GRB 180510A: MITSuME Ishigakijima optical upper limits
  8. GRB 180514A: 1.5m OSN optical observations
  9. GRB 180514A: GOTO Optical Observations
  10. GRB 180514A: Swift-BAT refined analysis
  11. GRB 180514A: Swift-XRT refined Analysis
  12. GRB 180514A: Enhanced Swift-XRT position
  13. GRB 180512A: VLT/HAWK-I NIR Observations
  14. GRB 180514A: Swift detection of a burst
  15. Konus-Wind observation of GRB 180510A
  16. GRB 180512A: Swift-XRT refined Analysis
  17. GRB 180512A: Swift-BAT refined analysis
  18. GRB 180512A: RATIR Optical Observations
  19. GRB 180512A: LBT optical detection
  20. GRB 180512A: Swift/UVOT Upper Limits
  21. GRB 180512A: LT prompt observations
  22. GRB 180512A: Enhanced Swift-XRT position
  23. GRB 180512A: GROND upper limits
  24. GRB 180512A: NOT upper limits
  25. GRB 180512A: OASDG optical observations
  26. GRB 180512A: Upper limits from OSN
  27. GRB 180512A: Swift detection of a burst
  28. GRB 180510A: Swift/UVOT followup observations
  29. GRB 180510B: Swift-XRT refined Analysis
  30. GRB 180510A: Swift-XRT refined Analysis
  31. Swift trigger 831888: misidentification of 4U 1416-62
  32. GRB 180510B: Swift-BAT refined analysis
  33. GRB 180510B: VLT/X-shooter observations
  34. GRB 180510B: GROND detection in all bands
  35. GRB 180510B: TAROT La Silla observatory optical observations
  36. Swift Trigger 831888: a possible GRB or Galactic transient
  37. GRB 180510B: Enhanced Swift-XRT position
  38. GRB 180418A: 15 GHz upper limits from AMI
  39. GRB 180510B: Swift detection of a burst with an optical counterpart
  40. GRB 180510A: Swift detection of a burst
  41. GRB 180427A: AstroSat CZTI detection
  42. Chandra observations of GW170817 reveal a fading afterglow
  43. Chandra observations of GW170817 260 days since merger: first statistically significant evidence for an X-ray decay
  44. GRB 180504A: Swift/UVOT Upper Limits
  45. GRB 180504A: Swift-BAT refined analysis
  46. GRB 180505A: Fermi GBM detection
  47. GRB 180416A: AstroSat CZTI detection
  48. GRB 180504A: ePESSTO NTT NIR observations
  49. Correction to Swift-XRT light curve fit for GRB 180504A in GCN 22685
  50. GRB 180504A: Swift-XRT refined Analysis
  51. GRB 180504A: NOT afterglow candidate
  52. GRB 180504A: Prompt enhanced Swift-XRT position
  53. GRB 180504A: Swift detection of a burst
  54. GRB 180416B: AstroSat CZTI detection
  55. Konus-Wind observation of GRB 180427A
  56. IPN Triangulation of GRB 180427A
  57. GRB 180427A: Fermi GBM detection
  58. Swift Trigger 829046 is probably noise
  59. GRB 180425A: Swift-XRT refined Analysis
  60. GRB 180425A: Swift-BAT refined analysis
  61. GRB 180425A: Swift/UVOT Upper Limits
  62. GRB 180425A: Enhanced Swift-XRT position
  63. GRB 180425A: Swift detection of a burst
  64. GRB 180418A: TAROT La Silla observatory early optical observations
  65. GRB 180418A: MITSuME Ishigakijima Optical Observation
  66. Retraction of IceCube GCN/AMON NOTICE 71165249_130949
  67. GRB 180418A : SQUEAN observations
  68. Fermi GBM trigger 545979055/180421202 is not a GRB
  69. GRB 180418A: Further GROND observations
  70. GRB 180418A: Swift/UVOT Detection
  71. GRB 180418A: Continued RATIR Optical Observations
  72. GRB 180418A: Imaging of the optical afterglow with the 1.3 m DFOT and 3.6 m DOT in ARIES, India
  73. GRB 180418A GROND observations
  74. GRB 180418A: Xinglong TNT optical upper limit
  75. GRB 180418A: NOT optical observations
  76. GRB 180418A: Gemini-North imaging and spectroscopy
  77. GRB 180418A: Swift-BAT refined analysis
  78. GRB 180418A: 1.5m OSN optical observations
  79. GRB 180418A: Fermi GBM observation
  80. GRB 180418A: Swift-XRT refined Analysis
  81. GRB 180416B: CALET Gamma-Ray Burst Monitor detection
  82. GRB 180418A: RATIR Optical Observations
  83. LIGO/Virgo G299232: LOFAR follow-up
  84. GRB 180418A: Enhanced Swift-XRT position
  85. GRB 180418A: Swift-XRT observations
  86. GRB 180418A: LCO FTN afterglow confirmation
  87. GRB 180418A: KAIT Optical Afterglow Candidate
  88. GRB 180418A: Swift detection of a short burst
  89. GRB 180404B: AstroSat CZTI detection
  90. GRB 180416A: Fermi GBM detection
  91. GRB 180409A: Swift-XRT afterglow detection
  92. GRB 180411A: CALET Gamma-Ray Burst Monitor detection
  93. GRB 180411B: CALET Gamma-Ray Burst Monitor detection
  94. Konus-Wind observation of GRB 180411A
  95. GRB 180411A: Swift/UVOT Upper Limit
  96. GRB 180411A: Tautenburg observations
  97. GRB 180410A: Fermi GBM observation
  98. GRB 180409A CALET Gamma-Ray Burst Monitor detection
  99. GRB 180411A: Fermi GBM detection
  100. GRB 180411A: Swift-BAT refined analysis

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