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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"

24828 results found.

  1. GRB 180514A: 1.5m OSN optical observations
  2. GRB 180514A: GOTO Optical Observations
  3. GRB 180514A: Swift-BAT refined analysis
  4. GRB 180514A: Swift-XRT refined Analysis
  5. GRB 180514A: Enhanced Swift-XRT position
  6. GRB 180512A: VLT/HAWK-I NIR Observations
  7. GRB 180514A: Swift detection of a burst
  8. Konus-Wind observation of GRB 180510A
  9. GRB 180512A: Swift-XRT refined Analysis
  10. GRB 180512A: Swift-BAT refined analysis
  11. GRB 180512A: RATIR Optical Observations
  12. GRB 180512A: LBT optical detection
  13. GRB 180512A: Swift/UVOT Upper Limits
  14. GRB 180512A: Enhanced Swift-XRT position
  15. GRB 180512A: GROND upper limits
  16. GRB 180512A: NOT upper limits
  17. GRB 180512A: OASDG optical observations
  18. GRB 180512A: Upper limits from OSN
  19. GRB 180512A: Swift detection of a burst
  20. GRB 180510A: Swift/UVOT followup observations
  21. GRB 180510B: Swift-XRT refined Analysis
  22. GRB 180510A: Swift-XRT refined Analysis
  23. Swift trigger 831888: misidentification of 4U 1416-62
  24. GRB 180510B: Swift-BAT refined analysis
  25. GRB 180510B: VLT/X-shooter observations
  26. GRB 180510B: GROND detection in all bands
  27. GRB 180510B: TAROT La Silla observatory optical observations
  28. Swift Trigger 831888: a possible GRB or Galactic transient
  29. GRB 180510B: Enhanced Swift-XRT position
  30. GRB 180418A: 15 GHz upper limits from AMI
  31. GRB 180510B: Swift detection of a burst with an optical counterpart
  32. GRB 180510A: Swift detection of a burst
  33. Chandra observations of GW170817 reveal a fading afterglow
  34. Chandra observations of GW170817 260 days since merger: first statistically significant evidence for an X-ray decay
  35. GRB 180504A: Swift/UVOT Upper Limits
  36. GRB 180504A: Swift-BAT refined analysis
  37. GRB 180505A: Fermi GBM detection
  38. GRB 180504A: ePESSTO NTT NIR observations
  39. Correction to Swift-XRT light curve fit for GRB 180504A in GCN 22685
  40. GRB 180504A: Swift-XRT refined Analysis
  41. GRB 180504A: NOT afterglow candidate
  42. GRB 180504A: Swift detection of a burst
  43. IPN Triangulation of GRB 180427A
  44. GRB 180427A: Fermi GBM detection
  45. GRB 180425A: Swift-XRT refined Analysis
  46. GRB 180425A: Swift-BAT refined analysis
  47. GRB 180425A: Swift/UVOT Upper Limits
  48. GRB 180425A: Enhanced Swift-XRT position
  49. GRB 180425A: Swift detection of a burst
  50. GRB 180418A: TAROT La Silla observatory early optical observations
  51. GRB 180418A: MITSuME Ishigakijima Optical Observation
  52. GRB 180418A : SQUEAN observations
  53. GRB 180418A: Further GROND observations
  54. GRB 180418A: Swift/UVOT Detection
  55. GRB 180418A: Continued RATIR Optical Observations
  56. GRB 180418A: Imaging of the optical afterglow with the 1.3 m DFOT and 3.6 m DOT in ARIES, India
  57. GRB 180418A GROND observations
  58. GRB 180418A: Gemini-North imaging and spectroscopy
  59. GRB 180418A: Swift-BAT refined analysis
  60. GRB 180418A: Swift-XRT refined Analysis
  61. GRB 180418A: RATIR Optical Observations
  62. LIGO/Virgo G299232: LOFAR follow-up
  63. GRB 180418A: Enhanced Swift-XRT position
  64. GRB 180418A: Swift-XRT observations
  65. GRB 180416A: Fermi GBM detection
  66. GRB 180409A: Swift-XRT afterglow detection
  67. GRB 180411A: Swift/UVOT Upper Limit
  68. GRB 180411A: Tautenburg observations
  69. GRB 180410A: Fermi GBM observation
  70. GRB 180411A: Fermi GBM detection
  71. GRB 180411A: Swift-BAT refined analysis
  72. GRB 180411A: Swift-XRT refined Analysis
  73. GRB 180410A: RATIR Optical Observations
  74. GRB 180411A: Swift detection of a burst
  75. GRB 180410A: Swift-XRT refined Analysis
  76. GRB 180410A: Swift-BAT refined analysis
  77. GRB 180410A: Swift/UVOT Upper Limits
  78. GRB 180409A: Fermi GBM observation
  79. GRB 180409A: Swift-XRT observations
  80. GRB 180410A: Enhanced Swift-XRT position
  81. GRB 180410A: Swift detection of a burst or a Galactic transient.
  82. IPN Triangulation of GRB 180409A
  83. GRB 180402A: ISON-NM early optical limits
  84. GRB 180407A: Swift-BAT refined analysis
  85. Swift Trigger 823014: TAROT Calern observatory optical observations
  86. GRB 180407A: COATLI Upper Limits
  87. Swift Trigger 823014 is probably not a GRB
  88. GRB 180404B: Swift/UVOT Detection
  89. Chandra observations of GRB161219B 400 days after the explosion
  90. GRB 180404A: Swift/UVOT Detection
  91. GRB 180404A: Swift-XRT refined Analysis
  92. GRB 180404B: Swift-BAT refined analysis
  93. GRB 180404A: Swift-BAT refined analysis
  94. GRB 180404B: Swift-XRT refined Analysis
  95. GRB 180404B: Enhanced Swift-XRT position
  96. GRB 180404A: MASTER-OAFA OT observation
  97. GRB 180404A: Enhanced Swift-XRT position
  98. GRB 180404B: Swift detection of a burst with an optical counterpart
  99. GRB 180404A: Swift detection of a burst with an optical afterglow
  100. GRB 180402A: Swift/UVOT Upper Limits

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